Monitoring Winter Body Condition

Cows in moderate body condition (BCS 5 to 6) usually require an average of about 55 to 65 days to resume fertile cycles after calving – meaning that mature cows that calve during the first 35 days of the calving season in moderate body condition should be cycling during the first 21 days of the next breeding season starts. In contrast, cows that calve with a BCS of less than 5 require more days to resume fertile cycles, and have very little chance of having fertile cycles by the start of the next breeding season – possibly not until late in the next breeding season.

Good body condition at calving is even more important for the reproductive performance of young cows that are nursing their first calves compared to mature cows because first-lactation cows often require 80 to 100 days to resume fertile cycles after calving. First-calf cows must have a BCS of 5 or greater (preferably 6) to have acceptable pregnancy rates for their second breeding season. In order to reach or maintain a BCS of 6 for first-lactation cows, they should be separated from the mature cowherd and fed to gain the needed weight.

During the winter months, most cattle in the U.S. are consuming dormant or baled forage. In most situations, the forage is poor to moderate in quality. When cattle graze marginal to low quality forages, supplemental protein or energy is often required to enhance either forage intake or animal performance. Poor quality forages (grazed or hay) have two negative effects on cow diets – the first effect is lower intake. While a 1250 pound cow will consume about 31 pounds (as fed) of moderate to good quality forage, she will only consume about 24 pounds of poor quality forage. The second negative effect is that the amount of energy per pound of intake is reduced compared to higher quality forage.

Because of year-to-year variation in forage quality and weather stress, cow body weight and condition can have important year-to-year variation even when fed what appears to be the same diet. Slightly lower forage quality and increased weather stress can result in cows losing more weight than expected. If cows lose condition over the winter so that that they enter the spring-calving season with a poor body condition, calf health and cow reproductive efficiency will be negatively affected.

In general, mature cows in good body condition that are not nursing a calf and that only need to maintain weight can over-winter on forage alone if forage quality is at least moderate and weather stress is low. If cows in good body condition are forced to consume lower-quality forage or if winter weather is harsh, supplemental high quality forage or concentrate will be required to maintain body weight. If cows are thin and need to gain body weight prior to calving, moderate quality forage will not supply the needed nutrients, and supplemental concentrate or high quality forage must be fed. If only poor quality forage is available, even greater levels of supplement must be fed to add body condition to thin cows prior to calving.

Young cows carrying their first pregnancy require energy and protein for their own growth as well as fetal growth, which makes their nutrient requirements higher than those of adult cows. Most dormant or baled forages do not provide all the calories needed for first-pregnancy cows over the winter, especially if the cattle face any weather stress. Ranchers should plan on providing young cows with supplemental high-quality forage or concentrate for at least part of the winter. The amount of supplement required depends on the quality of the base forage (grazed or baled).

In order to determine the amount of supplement required for the available forage, you need to be able to estimate how much energy reserve the cows’ are storing as body fat. Body condition scores (BCS) are used to describe the relative fatness or body fat reserves of a beef cow. The most commonly used system uses a range of 1 to 9, with a score of 1 representing a very thin cow and 9 representing an extremely fat animal.

Body condition scores are an accurate measure of body fat and are convenient in that cattle do not need to be weighed, merely observed and palpated at a time when other procedures are performed. Depending on mature cow size, there is approximately 80 to over 100 lbs. difference in body weight per BCS. When evaluating body condition, it is important to handle the cattle, so that one is not mistakenly evaluating hair coat, gut fill, or stage of pregnancy. The areas to palpate when determining BCS are: ribs, back, backbone, and tailhead. The entire herd, or a subset of each age group, should be evaluated for BCS during the winter to allow adjustments in winter supplementation to occur before cows lose excessive body weight.

It is very difficult for cows to gain body weight on dormant forage once they have calved and started lactating – even if heavily fed. Therefore, cows should reach their desired breeding body condition by the time they calve. In order to have enough days for thin cows to gain weight, herds should be evaluated 3 to 4 months prior to calving. If evaluated at this time, the weight gain for a BCS 3 cow to reach breeding condition (BCS 5) will be approximately 1.5 to 2.0 pounds per day (which is very possible with good forage and supplementation). In contrast, if cows only have 2 months to gain 2 body condition scores, they will need to gain over 3 pounds daily – a much more challenging task.

Anaplasmosis

By Bob Larson

Anaplasmosis is a serious disease that affects cattle in an increasing larger area of the country. A tiny organism called Anaplasma marginale attaches to red blood cells which leads to destruction of those cells and a decrease in the ability of affected cattle to carry oxygen in their blood. If more red blood cells are destroyed than the animal can replace with new cells – the blood becomes watery, the animal becomes anemic, and other signs of infection can occur, including: fever, depression, dehydration, rapid or difficult breathing, and yellow discoloration of the mucus membranes of the gums, around the eyes, and the vulva. Sometimes affected animals become excited and aggressive when not enough oxygen reaches the brain. Young animals are often able to recover because they can make new red blood cells very quickly, but older animals do not produce new cells very fast and they can quickly become very anemic and have very low oxygen levels in the blood leading to severe illness or death.

            Anaplasmosis is primarily carried from cattle to cattle by ticks, but the movement of blood from infected cattle to susceptible cattle can also be accomplished by biting flies such as horseflies, or by human activities such as via blood-contaminated needles, dehorning instruments, tattoo pliers, or palpation sleeves. The disease has historically been a problem in the southern parts of the United States but has now spread north so that cattlemen in many important beef-producing areas need to be aware of the problem. In herds that become exposed to the organism, cattle of any age can become infected, but the severity of illness is usually mild in young cattle and increases with age. In cattle that become infected when they are 3 years of age or older, 30% to 50% of animals showing signs of the disease are likely to die. If infected cattle are able to survive they are not likely to have severe problems due to the disease in the future, but they remain as carriers for the rest of their life. In some cases these carrier infections can be eliminated using antibiotic treatment.

            The first sign of anaplasmosis in a herd may be the sudden death of adult cattle. If anaplasmosis is identified as a cause of death and disease in a herd, cattle that are obviously sick should be kept as quite as possible and treated with an appropriate injectable antibiotic to kill the organism. In addition, tetracycline can be fed in the mineral mix or supplement to provide additional protection to the herd as directed by a veterinarian through a VFD document.

            For carrier cattle that don’t appear sick but that are infected with the anaplasma organism, your veterinarian can plan a treatment protocol using approved antibiotics administered over several days to clear the organism. However, treatment with antibiotics is not effective for all cattle and those animals that are cleared of the organism become susceptible to re-infection.

            The best plan to minimize disease lose due to anaplasmosis depends greatly on a farm’s or ranch’s geographic location and the number of cattle in the area that are infected. In parts of the country where anaplasmosis infection is rare, a strategy to find and treat and/or remove any carrier-animals is recommended. In contrast, in areas of the country where many cattle are infected, an attempt to remove all carriers from a herd will result in a herd that is susceptible to re-infection and the herd may have greater losses than if other strategies had been used to minimize the disease’s effects.

            If infected cattle are found in a herd in a part of the country where anaplasmosis is rare, one strategy to minimize disease loss is to test the herd for anaplasmosis infection and to treat any test-positive animals with an appropriate antibiotic as directed by your veterinarian. This treatment should be at a time of year when the local tick and fly population is the lowest. Because the treatment does not clear infection from every animal, the animals should be tested again about six months after the treatment and if an animal tests positive at this time, it should be considered a treatment-failure and removed from the herd, either by slaughter or by being sold to a herd in an area where anaplasmosis is common.

            In contrast, in herds located where anaplasmosis is common, rather than trying to avoid infection, some producers may want to allow infection to occur while the cattle are young in order to minimize obvious sickness and death loss. In some countries young animals are purposefully exposed to the organism allowing them to build immunity at a time in their life when the disease is mild. Although they will be infected for life, they are not likely to suffer severe illness. In some states in the U.S., your veterinarian may be able to obtain an experimental anaplasmosis vaccine that does not prevent infection, but is reported to reduce the risk of clinical signs and death. Producers may also elect to feed tetracycline under that direction of a veterinarian when the disease is most prevalent to control active infection and to use insecticides to control tick and fly populations.

            Because the best anaplasmosis control strategy for a particular farm or ranch depends on how likely that herd is to come into to contact with the organism, an important component of a control strategy is a plan to deal with replacement animals. If your herd is free of anaplasmosis and the risk of exposure is low, any replacement animal should be tested before being brought into contact with the herd. A test-positive animal should either be culled or isolated and treated and then re-tested six months after treatment. In contrast, if your herd is infected with anaplasmosis and the organism is common in your area, a test-positive replacement animal is desired, and the greatest health risk is in replacement animals that are not infected with the organism but that will be placed in direct contact with carrier animals. In this situation, one option is vaccination (if available) with close monitoring for clinical signs of the disease and quick treatment if disease is detected.

            Anaplasmosis control requires a good working relationship with your veterinarian to determine your level of risk and best control strategies. The best control strategy for your herd may be very different from that of your neighbors or cattlemen in other parts of the country.

Nutritional Aspects of Cattle Health

Bob L. Larson, DVM, PhD 
Beef Cattle Institute
Kansas State University

Meeting the nutritional needs of cattle is the foundation of a healthy herd. Nutritional needs differ between bulls, dry cows, lactating cows, growing replacement heifers, and post-weaning calves; and the nutrient composition of forages change throughout the year. Because of the interaction between changing animal needs and changing forage conditions, herd managers must be informed and prepared to provide appropriate supplements when needed. In almost all situations when cattle have the opportunity to graze green growing forages that are high-quality and readily digestible, the only supplement needed is salt (and based on local soil and plant characteristics, possibly other minerals). However, even green growing grass has the potential to cause health problems if the concentration of the mineral magnesium is low in the lush leaves at the same time that cows grazing the forage have high magnesium requirements due to being in early lactation or late pregnancy.  

While green growing forage is an excellent feed source for cattle, because of weather factors and growth characteristics of grass, for many weeks of the year cattle only have access to mature or dormant forage that has reduced quality and digestibility. Standing dormant forage and moderate-quality hay can meet most, if not all, of the energy and protein needs of cattle that have relatively low nutritional demands, such as mature cows that are not lactating and bulls that are not active. But if cattle are growing or lactating, dormant forage or hay may be deficient in energy and/or protein and these nutrients must be supplemented to avoid inadequate growth or even weight loss. The maturity and quality of forage when it is cut for hay as well as the conditions in which the hay dries before baling have tremendous impact on the nutrients present. Waiting to cut hay until the forage is very mature may increase the tonnage available, but the quality may be so low that either the cattle will not be provided needed nutrients or the needed supplementation drive up the total diet cost. Because growing replacement heifers, growing bulls, and cows in late stages of pregnancy or early lactation have high nutrient needs, these classes of cattle require higher quality forages or more supplementation of poor-quality forage than adult, non-lactating cattle.     

Because forages and readily available energy and protein supplements vary greatly across North America, knowledge of the local forages and feeds is essential when planning the most cost-efficient diets for cow herds. The types of predominant forage plants and the growth patterns of the different plants in diverse areas of the country greatly impact the quality of the diet for grazing cattle. Many forages and feeds have specific characteristics that affect not only the diet quality but also potential negative effects; and knowledge and experience is needed to avoid health and production problems. Use of some supplemental feeds has to be limited due to adverse effects when fed at higher levels. For example, the high starch content of corn and other grains limits their use in forage-based diets, the potentially high levels of sulfur in corn gluten feed, distillers grain, and some other by-product feeds requires that they be used in moderation, and gossypol in cottonseed meal can cause reduced fertility in bulls which requires that this feed be fed for limited time or in limited amounts in the weeks ahead of the breeding season.  

Cattle that are not receiving adequate amounts of water, energy, protein, salt and required vitamins and minerals can exhibit a wide range of problems that includes poor growth, weight loss, failure to become pregnant, hair and skin lesions, bone and joint problems, and susceptibility to sicknesses such as pneumonia, scours, and nervous system disease. Unless underlying nutritional problems are identified and corrected, use of vaccines, antibiotics, and other interventions will not improve heard health. In many situations, outright disease is not detected, but nutrient deficiencies are negatively impacting body weight and fertility of the herd. 

Fortunately, cattle will thrive on many different types of forages and feeds. The rumen has the ability to convert moderate- and even low-quality feeds into needed nutrients. Because cattle can eat a wide variety of feeds, locally available products that could not be easily shipped to other parts of the country or could not be used in other animal diets can serve as excellent cattle feeds. Knowledge of the nutrient needs of different classes of cattle as well as experience with local forages and feeds will allow cattle producers and their advisors to develop cost-effective diets that meet the needs of cattle to maintain good health and productivity. 

Health Risk when Purchasing Cattle

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

One issue in the buying and selling of cattle that is often not considered until a problem arises is the health aspects of the transaction. While every business deal involves some risk, including health risk, the level of risk is not the same for every transaction and producers and their veterinarians have options to lessen the likelihood and/or extent of negative outcomes.

In general, the less health information that is available for a sale animal, the greater risk the purchaser is taking. In many situations, the seller does not does not possess specific information about the health of the cattle they are selling or the potential negative outcomes that may occur when the purchased cattle are introduced into the buyer’s herd. Because a number of negative health outcomes can follow the introduction of new cattle into a herd, the buyer needs to beware of taking greater risks than should be reasonably expected.

When purchasing cattle to introduce into an existing herd, some potential health risks include: injury during transport, the stress of transport and a new environment causing a purchased animal to break with disease leading to illness of the purchased animal or transfer of germs or parasites to the herd, the purchase of cattle that have not been exposed to the germs commonly found in the home herd leading to illness of the purchased animals, and purchasing an animal that is a persistent carrier for an infectious disease and exposing the home herd to an unfamiliar germ.

The risk of injury can be decreased though careful handling and good loading, unloading, and transport equipment. Good design and maintenance as well as appropriate flooring and bedding in transport trailers along with a transportation plan that includes considerations of length of travel, weather exposure during travel, and skill of the driver to avoid excessive fatigue on the part of the cattle being moved are all considerations to reduce the risk of injury of purchased cattle.

Cattle that are stressed are more likely to become ill and to shed germs and parasites that can be spread to other cattle. Even when healthy cattle are transported to a clean environment in safe transport trailers, some level of stress can be expected. This potential period of greater susceptibility to disease and greater risk of exposing other cattle to disease-causing germs is the reason that veterinarians recommend that cattle being added to a herd are separated (quarantined) from the current herd for a period of at least 30 days so that the new cattle can become completely acclimated and can have recovered from the stress of being transported to a new environment.

Even though the purchaser of new cattle are often concerned about any germs or parasites that the new cattle may be bringing into their current herd, an equally important risk is that newly purchased cattle may be exposed to unfamiliar germs present in the home herd – causing the new cattle to become sick. This risk can be addressed by using a period of time after the original 30 days of complete separation from the current herd to allow limited contact of the new additions with a few cattle from the original herd. Older cows or animals that are being culled are often used for this purpose.

And finally, the risk that many veterinarians and producers consider first when protecting a herd from the risk of introducing new cattle is purchasing an apparently healthy animal that is a persistently infected carrier of a disease that is not currently a problem in the herd. There are a number of important diseases that can enter a herd by the purchase of a carrier animal. In my opinion, the diseases that fall in this category that deserve the greatest attention in many parts of the U.S. are trichomoniasis (trich) and bovine viral diarrhea (BVD). Other diseases that have persistent carriers and that may be of particular concern for some herds include: anaplasmosis, Johne’s, and bovine leukosis virus (BLV).

Because of the amount of loss that can occur and our current disease-control abilities, no herd should tolerate the import of cattle infected with trich or BVD. However, for some of the other diseases that have persistently infected carriers, it is not always wise to insist in imports being free of the disease-causing germs. For example in some parts of the country where anaplasmosis is extremely common, it may be better to purchase cattle that have been exposed to the organism previously and are themselves carriers. In contrast, if you live in an area with very low anaplasmosis risk, you need to protect the home herd by purchasing cattle that are not carriers. For diseases such as Johne’s and BLV, many herds already have carrier animals and insisting that purchased replacements be negative won’t make much impact on the current herd’s health status.

In summary, my advice is to have plans to keep any cattle potentially infected with trich or BVD out of a breeding herd and to know the status of your herd for any other infectious agents you may want to exclude. Work closely with your veterinarian to develop the best for your specific herd to manage the risks of brining in new cattle to your herd. In many situations, it is helpful for your veterinarian to talk to the supplier’s veterinarian so that the health status of your herd and the source herd can be compared. You should have a quarantine time when you can watch herd additions closely for at least 30 days. If any of the purchased cattle show signs of illness during that 30-day period – keep them quarantined longer so that a full 30 days passes after the last episode of illness until the new cattle are allow to have contact with your herd. At the end of the quarantine period, consider exposing the herd additions to older (possibly culls) cattle so that purchased cattle are exposed to the home-herd’s germs and parasites while you can still watch them closely.

Purchasing herd additions that meet the genetic and marketing goals for your ranch is an important part of ranch management. Managing herd additions to limit the health risks involved is an often overlooked consideration in the transaction.

Coccidiosis

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

Coccidiosis is an important disease of cattle caused by a small parasite that invades the cells of the intestinal tract and if enough intestinal cells are damaged, diarrhea or bloody-diarrhea can result. You may have heard of other species that also can suffer from coccidiosis, including poultry and swine. However, although most animal species can be infected with coccidia organisms, the specific types that cause disease in other species will not cause problems for cattle – cattle disease is caused by cattle coccidia. Almost all cattle are infected with at least a few coccida organisms, but problems only occur if the parasite can multiply rapidly – usually when cattle are stressed. The stress of weaning, trucking, weather insults such as winter storms or mud, over-crowding, or poor nutrition can all allow individuals or groups of cattle to suffer from coccidiosis.

Recently weaned cattle, particularly if they are exposed to inclement weather or mud and are shipped to a new location are considered to be at high risk for coccidiosis. Young suckling calves can be affected, particularly in situations with poor sanitation, nutritional stress, and other causes of diarrhea. Adult cattle that remain in the herd are usually immune to the local coccidia, but thin cows can be at risk. In addition, bringing in new cattle can cause an outbreak of coccidiosis in the new animals when they are exposed to the local coccidia – or the new animals may bring in a new species of coccidia and cause an outbreak in the original herd.

The most common signs of coccidiosis are watery diarrhea, diarrhea with blood, straining to defecate, a rough hair coat, and poor weight gain. In addition, some affected cattle in a group can show signs of nervous system problems such as tremors, eye twitching, and convulsions. Many cattle with coccidiosis appear healthy but they have decreased weight gain and feed efficiency. Mild cases that involve a few days of watery feces without noticeable blood where the cattle do not become obviously depressed or off-feed are also common. Severe cases with a week or more of bloody diarrhea can lead to a fever, becoming off-feed, and being depressed and dehydrated. If the infection is mild, death is very rare, but in more severe cases, death is fairly common due to coccidiosis itself or the coccidiosis can increase the risk for other severe diseases such as pneumonia. Cattle with nervous system symptoms have a very high risk of death.

Your veterinarian is most likely to diagnose coccidiosis after examining cattle with bloody diarrhea and ruling out other problems. The organism can often be detected in high numbers in fecal samples, but this test is not always accurate because intestinal damage can occur before large numbers of coccidia are found in the feces. In addition, some cattle may have high numbers of coccidia in their feces, but be nearly recovered from the disease and are in much better shape than cattle with few or no organisms earlier in the disease process.

A number of treatments are available for cattle suffering from coccidiosis, and affected cattle should be separated from the group so they can be kept comfortable while being individually treated with fluids to correct dehydration and with drugs that will kill the organism. Whenever one or more cattle in a group have obvious signs of coccidiosis, you can assume that the rest of the group has been exposed and is likely to be suffering less obvious losses.

To prevent coccidiosis, good animal husbandry practices to improve sanitation and reduce stress are important. The organisms survive very well in the environment and it is probably impossible to completely remove them from areas where cattle live. Young animals should be kept in as mud-free an environment as the weather will allow; and feed and water should be kept off the ground as much as possible to minimize fecal contamination. To reduce stress, castration and dehorning should be done at a young age several weeks ahead of weaning, and low-stress weaning strategies should be implemented wherever possible. In addition to management strategies, a number of treatments such as ionophores, decoquinate, or amprolium can be delivered by feed or water to groups of cattle to minimize the risk of severe disease. A month or more of daily intake of these preventative treatments is necessary to break the life-cycle of the organism.

As with many diseases, good sanitation and animal husbandry are important to prevent and control coccidiosis. In addition, your veterinarian can recommend products to treat affected cattle and preventatives that can be used during periods of highest risk for the disease.

Liver Flukes

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

Liver flukes are a large flat worms that can invade the liver of cattle. The United States Department of Agriculture (USDA) reports that about 5% of slaughtered cattle are infected and their livers are condemned. Liver flukes cause economic loss through liver condemnation at slaughter as well as decreased growth and reproductive efficiency. In addition, Black disease and redwater disease are caused by clostridial bacteria that live in soil (same family as the organism causing blackleg) and if they get a “foothold” in the liver due to damage caused by flukes, these diseases can be fatal.

Because these parasites requires a specific type of water-living snail for some stages of the lifecycle, cattle in many parts of the country are not at risk; but in areas where certain snails are commonly found, a high percentage of adult cows can be infected. Cattle can only be infested by eating snails that have been infected by fluke larva. The most common fluke infesting cattle is Fasciola hepatica. The other common liver fluke is the giant deer fluke or Fascioloides magna.

Cattle most likely to be affected with F. hepatica are those in certain parts of the country that are grazing in low-lying swampy areas, flood irrigation areas, or anywhere that surface water or small, slowly moving streams favor large populations of snails. The snail that serves as the intermediate host of Fasciola hepatica is found in the Gulf Coast states and some western states. The giant deer fluke is a problem in Gulf Coast states, the Great Lakes region and the Pacific Northwest where it naturally infests deer, elk, and moose. Cattle can also become infected with the giant deer fluke and experience liver damage, but this species of fluke cannot fully mature and lay eggs when infecting cattle. In the Gulf Coast states, most fluke transmission occurs between the months of February and June. Transmission stops with the death of fluke eggs, snails, and immature flukes in the first sustained drought of the summer. In the Pacific Northwest, cold winter conditions inhibit snail and fluke reproduction.

Young flukes cause extensive liver damage as they move through the liver, but they are difficult to kill at this stage of the lifecycle. The amount of damage to the liver is related to the number of young flukes migrating through – with some cattle showing few or no signs of problems and other cattle experiencing severe problems such as diarrhea, weight loss, and a yellowing of the membranes around the eyes and vulva in heavily infested cattle. Adult flukes cause very little damage, but are relatively easy to kill with available treatments.

Even though cattle living in many states cannot become infected with flukes, cattle already infected can be transported to any part of the country and be diagnosed far from the source of the flukes. Most cattle infested with liver flukes do not appear unhealthy, and death is very rare. Some mildly infested cattle have no reduction in performance but cattle with a higher level of infestation will have decreased weight gain, poorer body condition, and decreased milk production. The poorer body condition of cows infested with flukes may lead to decreased pregnancy rates. 

Diagnosis often occurs during a necropsy or at slaughter. F. hepatica can sometimes be diagnosed by testing a manure sample, but because fluke eggs are much larger than other cattle parasite eggs, the tests commonly used for other cattle worm eggs may not detect fluke eggs even if they are present. Another problem with relying on manure sample tests to diagnose fluke infections is that flukes less than 2 to 3 months of age are immature and unable to lay eggs. Therefore, cattle can be showing signs of diarrhea and weight loss due to migrating young flukes, but the test will be negative. Even in older infections, few flukes reach adulthood and they pass a small number of eggs – therefore, an animal with a heavy fluke population could have a negative test. Because Fascioloides magna (the giant deer fluke) does not complete its life cycle in cattle, no eggs are produced or passed in the manure, so the only way to diagnose infections with this species is at slaughter or necropsy.

Most dewormers available for treatment of cattle parasites do not affect flukes. Your veterinarian can help you identify one of the available treatments that can be used in fluke infections, but these treatments only are effective against adult F. hepatica flukes (greater than 11 weeks of age) and are almost totally ineffective against Fascioloides magna (giant deer flukes). Timing of fluke treatment is very dependent on your location and grazing pattern, therefore if you live in an area with a risk of liver fluke infection, you should work with your veterinarian to devise an appropriate control plan. Removal of adult flukes will not decrease risk of liver condemnation, because the damage has already been done, but it does enhance performance in severely fluke-infested cattle and may help decrease exposure of snails living in your pastures to the fluke eggs. Prevention in areas of the U.S. that harbor the snails necessary for the liver fluke lifecycle involves draining shallow stagnant ponds, fencing cattle away from shallow bodies of water, or treatment of infested water to remove snails.

Internal Parasites

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

Internal parasites (or worms) have historically been among the most serious health problems facing cattle. A number of types of internal parasites can affect cattle, including: roundworms, liver flukes, and coccidia. Roundworms primarily live in the gut (stomach and intestine) with one exception being lung worms. Roundworms cause problems for cattle through several pathways including damage to the lining of the digestive tract, reduced forage or feed intake, and stimulation of excessive release of chemicals by the body in an effort to destroy the parasites.

Roundworms spend part of their life cycle in the gut of cattle, while some life cycle stages must take place on pasture grasses. Adult roundworms live in cattle and produce eggs that pass out in the manure. The eggs then hatch to form immature stages that must mature on pasture. These immature stages of the parasite are eaten along with grass as cattle graze. How quickly the eggs hatch and how likely the immature forms of the worms are to survive depends on the climate (temperature and moisture), with warm wet conditions leading to rapid development and high likelihood of survival and very hot or very cold and dry conditions leading to reduced survival. In general, it takes about two to three weeks for eggs deposited in manure to develop to the stage where they can infect grazing cattle, and then they can survive for several months on infected pastures. Once inside the cattle, the parasites complete the life cycle in two to eight weeks – when they gain the ability to lay more eggs.

Calves and yearlings are the most likely classes of cattle to exhibit obvious signs of parasite infection – including weight loss, diarrhea, swelling under the jaw, dull hair coat, and unthrifty appearance. Parasite-infected adults often have weight loss or reduced weight gain, but otherwise appear healthy; although even adults can have obvious signs of parasite infection if the exposure is heavy enough or if poor nutrition or disease compromises their overall health. Heaviest exposure to internal parasites tends to occur in parts of the U.S. with warmer climate, high rainfall, and high stocking density with long grazing seasons that allows the worms to have continuous life-cycles throughout the year (i.e. southeast and south-central regions). In colder and dryer climates, the stocking density is lower and the worms have fewer life cycles in a year because there are fewer months of ideal conditions; this results in reduced parasite exposure. Regardless of the climate, the highest risk of severe parasite loads in cowherds is late in the grazing season.

The discovery of chemicals after World War II that can kill or inhibit roundworm parasites with reduced risk of toxicity to animals compared to earlier treatments have given stockmen valuable tools to decrease the health costs of these challenging adversaries. But in order for dewormers to work well and to maintain their effectiveness, parasite control must involve more than just chemical treatments.

Because young calves and yearlings are more negatively affected by internal parasites than adults, and because some pastures have very high parasite contamination while others will have very light contamination, planning a grazing strategy that places the highest risk cattle on the lowest risk pastures is an important method to minimize losses due to worms. In general, because young cattle tend to be highly susceptible to parasite infection and they quickly develop high parasite burdens, young cattle should not be grazed continually on the same pasture in parts of the country with severe worm challenges, nor should one group of young cattle immediately follow another group of young cattle on the same pasture. Pastures that have not been grazed in order to harvest hay, pastures grazed only by adult cows (without calves at-side), crop residue fields, and pastures grazed by other species such as sheep or goats would all be likely to have low parasite contamination and are ideal for young cattle.

Young cattle have very poor immune protection from internal parasites, but starting at about one year of age, cattle gain the ability to mount an effective immune response for most roundworms (and 18 months of age for the Brown Stomach Worm). If cattle can be protected from high parasite exposure until they are 12 to 18 months of age, they will develop a strong immune response without suffering serious loss. By combining grazing management with timely treatment with deworming products, cattle producers can have very effective parasite control while avoiding the over-use (or under-use) of chemical dewormers.

There are three main classes of chemical dewormers available in the U.S. with several product brands within each class. The primary purpose of chemical dewormers is not to treat cattle that have become sick or negatively affected due to high worm burdens; instead, these products should be used to limit parasite contamination of pastures so that cattle are not greatly affected in the first place. In general, cattle should be treated as they are being turned onto a pasture with a low parasite burden when the conditions are good for parasite survival. In regions of the country with heavy stocking rates and favorable environments for worms (e.g. southern U.S.), young cattle may require two or more treatments at three to six-week intervals during periods of the year that are most favorable to the parasites. None of the available products will work well if treated cattle are turned out onto heavily contaminated pasture.

More aggressive treatment and careful monitoring of conditions is vital in the southeast and south-central portions of the U.S. compared to the high plains and western states because of vastly different risks of negative effects due to internal parasites. Because the best roundworm control strategy will vary greatly from one part of the country to another and between different farms and ranches within the same area because of management options, it is important to work with your veterinarian to plan the optimum control strategy.

Lead Poisoning

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

Many times when we think of cattle diseases we concentrate on infectious diseases caused by bacteria and viruses, or we may think of parasites such as worms, lice, and flies. But, it is important to remember that poisons can also cause rapid death and severe illness in cattle. Cattle, especially young calves, can be very curious about unusual items found in their environment, and they often explore with their tongues and mouths. Sometimes cattle will find and consume improperly disposed of farm chemicals or industrial chemicals around discard piles, electrical transformers and power line poles, or oil pump jacks, but the most common form of poisoning in cattle is due to eating lead. The most common sources of lead include batteries from electric fences and discarded vehicles, old radiators, used crankcase oil, grease from machinery, lead shotgun pellets, construction materials such as putty, lead plumbing, and old paint, and ash from fires where lead-contaminated construction materials were burned. If you ranch in an area with lead mines, the soil and water can be high in lead.

High levels of lead in the body affect red blood cells, bone marrow, and small blood vessels. It will cause abnormal signaling between nerve cells, and will severely damage the kidneys and other organs. In fact lead can have many different negative effects on the body because it can interfere with many different types of enzymes and chemicals necessary for normal body function.

Cattle are more sensitive to lead than most other species and don’t have to consume very much lead to have very sudden and severe problems. Many times, the first sign that a rancher notices is one or more dead calves within a day or two of being exposed to a source of lead. Other calves (and occasionally older cattle) in the group may appear to be blind or they may circle or press their heads against solid objects, cattle may have muscle tremors, teeth grinding, frothing at the mouth, or signs of colic. Cattle with any of these symptoms usually die within 12 to 24 hours. These signs can be very similar to other diseases such as grass tetany, polio, nervous coccidiosis, listeriosis, or rabies, so a veterinarian should be called to investigate the problem.

Because cattle are very sensitive to lead, even small amounts cause severe disease and death in at least part of the herd. Other species are not as sensitive to lead and my show mild signs of illness when exposed. Occasionally, rather than dying, older cattle or cattle exposed to very low doses of lead may show digestive tract problems such as going off feed, becoming constipated or colicky, or having diarrhea. This may be followed by signs of brain or nervous system problems such as blindness, head pressing, or staggering. Infertility of both bulls and cows has been reported following exposure to low levels of lead over a long period of time.

If calves that die due to lead poisoning are necropsied (cut open to examine the body organs), the veterinarian may find nothing that indicates the cause of death, or he/she may find some reddened intestines or lungs – which could look like a clostridial disease or pneumonia. Occasionally, the veterinarian may find evidence of unusual stomach contents, but samples of blood or kidneys are the best samples to diagnose lead poisoning.

It is generally not recommended to treat cattle with signs of lead poisoning because the treatment is very unlikely to be successful. Cattle with lead toxicity are not fit for human consumption because high lead levels can be passed to consumers through the meat. In fact, up to a year or longer after a confirmed lead exposure, cattle that were possibly exposed to lead should have a blood sample tested before they are sold into marketing channels leading to human consumption because they may be carrying high levels of the dangerous mineral. There is no known use for lead in the human body and no acceptable level in the human diet because of its severe negative effects; therefore, every attempt must be made to keep lead out of the food chain.

If lead poisoning is suspected, immediately remove all cattle from the pasture. Treatment begun before signs of disease are noticed may be helpful, and you and your veterinarian may choose to treat young calves that were exposed to lead but that are not showing signs of poisoning. There are treatments given by stomach tube to try to flush the lead out of the digestive tract (magnesium sulfate – Epsom salts), high doses of thiamin (a B-vitamin), and a compound administered into the bloodstream (calcium-EDTA) to tie-up lead circulating in the blood. The treatment of lead poisoning requires multiple treatments per day over several days of therapy and calcium-EDTA administered into the blood is expensive.

This serious problem can be prevented by making sure that your cattle cannot come into contact with old cars or farm equipment, batteries, construction materials, lead paint, or old burn piles. Many times, old equipment or trash piles have been present in a pasture for many years with no problems and then because something disturbs the trash, a fence is moved, or younger cattle are placed in the pasture, cattle can suddenly die of lead poisoning.

Research and Innovation

Bob L. Larson, DVM, PhD

Beef Cattle Institute

Kansas State University

Changes in the tools and solutions available to address beef cattle health and production concerns are being driven by both time-tested and new areas of research and innovation. The advances being made in genetics, geographic information systems, nanotechnology, and computing power are exciting and provide researchers with new tools to learn about cattle nutrition, reproduction, grazing, health, and behavior. But all innovations are built on foundational knowledge of animal husbandry and the daily needs and characteristics of cattle.

Genomics and related research areas such as proteinomics, lipidomics, and other “omics” are used to study the molecules that are inside cells including DNA, RNA, proteins, fats, and carbohydrates. New laboratory tools are being developed to allow animal and veterinary scientists to investigate how different cattle respond to different nutrients, disease challenges, and environmental factors at the cellular level.  These types of studies were not possible just a few years ago, and it is hoped that learning about what is happening in the cells will help explain differences we see in living cattle.

Geographical Information Systems (or GIS) uses maps and other data to ask questions about the characteristics of specific places and the animals, plants, and environment associated with those places. From GPS and GIS technologies in our cars, phones, and farm equipment, “precision agriculture” is changing the way food producers think about using land, animals, labor, and other resources so that each square-foot of land or each individual animal is managed for its own optimal production, rather than for optimal production at the herd or field level. GIS also allows researchers with different areas of expertise such as soil health, forage production, water quality, plant health, cattle health and growth, meat science, and economics to add “layers” to the information for each area and animal on a ranch so that scientists can study complex trade-offs between different aspects of cattle production.

Nanotechnology and nanoscience is the use and study of extremely small things (less than 100 nanometers in size) created to serve many different purposes. To understand how small these devices are – there are over 25 million nanometers per inch, so more than 250,000 of the largest nanodevices could fit in an inch. New microscopes that allow scientists to see things as small as an atom have allowed this area of research and innovation to move rapidly from science fiction to marketable products. Nanodevises could be used to deliver small doses of drugs to parts of the body that are affected by disease and to avoid parts of the body that could have a toxic reaction. Other nanotechnology will likely be used to deliver nutrients, detect disease, and improve meat packaging.

All of these areas of innovation are made possible by rapidly increasing computing power which takes the relatively simple task of doing math problems and allows scientists to ask deeper questions about nature and cattle production. The amount of numbers that are generated by studies using genomics (and other “omics”), GIS, and nanoparticles can only be organized and evaluated using computing speed that was not available until recently. New ways of collecting and storing data and doing math are being developed to keep up with growing amounts of information generated from innovations that are investigating both smaller and larger environments associated with cattle production.

It might be easy to become excited (or appalled) by the innovations that are changing the way scientists do research; but as I look at those who are doing the most beneficial projects, I see animal and veterinary scientists who combine an appreciation for cattle and cattle producers with their knowledge of the latest tools to investigate the mysteries of biology. It seems to me that the more we learn about cattle the more we realize how much is still hidden. By appreciating how amazing cattle and the rest of biology are, scientists take small steps toward understanding the things we see every day – cattle eating grass, growing muscle, becoming pregnant, being challenged with disease, recovering from disease, and serving an important and complex role in the earth’s ecosystem. Although the tools that are the result of and drivers of innovation tend to be complex, the questions that drive cattle research are straightforward and similar to the questions asked by animal and veterinary scientists for generations: How to best utilize forage resources? How to meet the nutrient needs of cattle throughout their life? How to identify individuals with the most valuable genetic traits? How to grow and harvest muscle tissue that makes the most desirable food? And, how to diagnose and treat animals that become sick? In my opinion, the tools aren’t what makes a good scientist, my science heroes have a love for biology, for cattle, and for discovery that makes them want to continue learning throughout their life and to serve cattle and cattle producers by finding solutions to life’s everyday challenges.

Animal Welfare and Consumer Relations

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

Providing a safe and healthy environment for cattle is not only the foundation for good animal welfare and efficient production, but is also necessary in order to maintain a positive image of cattle production for consumers.

Day to day care for cattle requires that producers meet each herd’s nutritional and health needs as well as provide housing and handling facilities to ensure their safety and welfare. Cattle are able to eat a wide variety of forages and feeds to meet their nutritional needs. When cattle of almost any age and stage of production are housed on green, growing pastures, they are not likely to require a great deal of additional feed. However, salt and other minerals are required in all cattle diets, and growing calves and yearlings, and lactating cows and heifers require diets that are higher in energy and protein than dry cows and bulls. Cattle grazing dormant forage or being fed harvested hay or other forages may require a supplemental feed or forage that has higher concentrations of energy or protein than the base forage. This supplement may be in the form of high quality hay, grain or grain-byproducts, or other processed feeds. Evaluating weight gain in growing animals and body condition in mature animals provides cattle producers with a simple measure of whether or not a diet is meeting the energy and protein needs of their cattle.

Providing plenty of readily accessible water is another key component in meeting the daily needs of cattle. While well-informed people may disagree about how long cattle can be held away from water without adversely affecting their health and welfare, the basic principle that cattle need plenty of clean water is undisputed. The time of year, the number of cattle, and whether the cattle are near the water source throughout the day or only part of the day all impact the amount of space and the flow rates required. Hot temperatures in summer increase the daily requirement for water and the potential for freezing increases the risk of failed water delivery in the winter. Range situations when cattle are only near the water source for a limited amount of time each day require greater one-time access space and water reserve than cattle housed in small pastures or drylots with continual access to water. Stock tanks or waterers that are not cleaned can result in reduced water intake; and mud, erosion, or other obstacles that make it difficult for cattle to approach a water source can lead to health and welfare problems.

Beef cattle are nearly always housed outside on pastures or drylots which usually means that air quality and sanitation is good. However, cattle housed outdoors in most parts of North America must contend with extremes in temperature and humidity during certain times of the year. Extremely cold and hot temperatures can cause severe stress and health problems. When rainfall is heavy, excessive mud can prevent comfortable resting and be a barrier to feed and water access. Making sure that cattle are protected from extreme wind chills by the use of natural or man-made wind breaks and providing access to shade or other relief during periods of high heat index are important considerations for cattle housed outdoors. In addition, all fences, feed bunks, water troughs, and handling facilities should be designed and maintained so that cattle are not likely to injure themselves and so that the facilities can be used as they were intended. Everyone who works with cattle should understand and implement low-stress handling techniques to minimize the risk of cattle becoming injured or exhausted during handling. To implement low-stress handling, a ranch must have appropriate facilities and well-trained cowboys or animal handlers.

Providing cattle with proper diets, treating for internal parasites (worms) and external parasites (flies, lice, ticks, etc.), protecting the herd from avoidable contact with disease carriers, and using appropriate vaccines not only helps to protect the health and welfare of cattle, but supports high productivity of the herd. By concentrating on nutrition, sanitation, parasite control, biosecurity, and vaccination, ranchers can ensure that they are focusing their efforts to meet the health and welfare needs of their herd.

In addition to meeting cattle’s daily needs, every cattle producer must be prepared for potential challenges such as drought, hurricanes, tornadoes, floods, fire, blizzards, and other natural or man-made disasters. While most disasters cannot be avoided, those that are reasonable possibilities should be thought about ahead of time. Planning for ways to provide feed, water, and shelter to the herd as soon after a disaster as possible guarantees that animal welfare will be minimally compromised.

And finally, every cattle producer needs to have a plan for how he or she will deal with a severely injured or ill animal. Although providing an excellent environment with appropriate diets and a good herd health program will minimize the risk of disease and injury, all ranchers know that recognizing when an animal should be euthanized is critical to ensuring the humane care of their herd. Appropriate methods to euthanize (put to sleep) cattle have been recommended by the American Association of Bovine Practitioners and the American Veterinary Medical Association. Every ranch should have at least one person who is trained to appropriately euthanize cattle or should have access to a veterinarian to perform this important function.

Time-tested principles of good cattle management are the keys to assuring the health and welfare of cattle herds. Increasingly, consumers are also interested in knowing that cattlemen are concerned about the welfare of their animals. It is becoming very important that you have a management plan that you can share with anyone who asks so that beef consumers can be assured that you also value the health and welfare of your herd.

Use of a BVD Management Tool: BVD CONSULT

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

Bovine viral diarrhea virus (BVD) infection is responsible for a variety of economically important disease syndromes in beef herds. The economic losses from BVD infection in cowherds will vary based on herd immunity and stage of gestation at the time pregnant cows are exposed to the virus, the virulence of the BVD strain, and other factors. The virus is known to suppress the immune system, contribute to the risk of pneumonia, and to cause pregnancy losses. Infection of the fetus with BVD virus during pregnancy can lead to abortion, birth defects, or the birth of persistently infected (PI) calves. Persistently infected cattle can result when susceptible pregnant cows are exposed to BVD virus during the first half of pregnancy. Many times infected fetuses are aborted, but if a PI fetus survives to term, it will always have a tremendous amount of the virus in its body and cannot mount an immune response to clear the virus. A PI animal will secrete BVD virus throughout its life; in contrast to animals that become infected after birth that secrete the virus and are contagious for only a few days to two weeks. These PI calves constitute the main source of BVD virus for spread within the herd and to other herds of cattle. Cattle persistently infected with BVD virus can be identified by a number of laboratory tests. Based on a recent USDA study, while only 8.8 percent of U.S. cow-calf ranches had one or more PI animals identified; this means that one in every 11 to 12 herds have PI calves and most ranchers with infected herds are not aware of the presence of PI calves.

Vaccination programs can provide fairly good protection against BVD-induced disease when the exposure is from non-PI animals that shed the virus for a short period of time. Vaccination programs offer some protection against BVD-induced disease when the exposure is from PI animals but this protection may be incomplete because of the tremendous amount of virus excreted by PI animals. Vaccination programs are an important component in BVD control, but will only offer a high level of protection if herd contact with PI animals is eliminated.

The cattle industry has made significant efforts in recent years to control BVD. Our current knowledge of the virus, the availability of effective vaccines, and the improvement in diagnostic tools have made the control of BVD feasible.

BVD CONSULT (Collaborative, Online, Novel, Science-based, User-friendly, Learning, Tool) is an internet-based tool, designed to aid in the development of BVD control programs for cow-calf herds. It is the result of efforts by scientists from several universities from around the country (Kansas State University, the University of Nebraska, Mississippi State University, and Auburn University) and was funded by an educational grant from Zoetis Animal Health and the USDA. BVD CONSULT effectively draws available BVD research into a user-friendly and organized format to develop BVD prevention and control programs for individual herds that emphasizes key management decisions that impact the success of these programs. 

BVD CONSULT provides veterinarians and cow-calf producers an opportunity to develop BVD prevention and control programs for any cow-calf herd. For herds that currently have PI cattle present, the tool will help to create a plan to identify and remove the PI cattle and to establish a strategy to reduce the likelihood of the herd becoming infected again. For herds that are currently BVD-free, BVD CONSULT can be used by a producer and the herd veterinarian to decide how to minimize the likelihood of BVD virus entering the herd and to reduce the impact if the herd is exposed.

BVD CONSULT is set up as a series of questions with responses and was designed to mimic a conversation between a veterinarian and a producer who is concerned about BVD.  The tool works through a decision tree in order to provide recommendations that are specific to individual operations. BVD CONSULT asks if the producer is willing and able to perform specific management practices that will aid in prevention or control and eradication of BVD.  More information is available in the tool to help with the decision making process.  After clicking on “yes” or “no” to each question, an appropriate response is given based on the choices that have been made, followed by another question. The questions that are asked, and the responses given, vary depending on the previous answers. There are 6 to 10 questions in total depending on the choices made. A printable report is available at the end of the tool which records the choices that were made and the responses that were given. The final result is a set of recommendations that the rancher and herd veterinarian have designed to meet the specific needs of a particular cow-calf herd. BVD CONSULT, as well as many other BVD management resources, can be found at www.BVDinfo.org.

Networking in the beef industry

Bob L. Larson, DVM, PhD

Although cattle producers often find that it is necessary to rely on themselves and to develop a wide variety of skills; successful cattle producers also know that it is important to identify others outside their operation who will provide benefit to their ranch. People who are trained to help and who have an economic incentive to ensure that your ranch thrives are ideal networking partners. The most likely networking partners are often located very close to your ranch, but can come from the wider region, other areas of the country, or occasionally from other parts of the world.

The Japanese word keiretsu is used to describe a business system where companies are linked in one or more ways due to serving the same geographic area, working with the same lender, having some cross-ownership,  or being related by blood or marriage – and that do a great deal of business with each other. In business schools, networks of large companies in manufacturing or technology are used as examples of keiretsu, but when I first heard this word – I immediately thought about my hometown and many similar situations in rural America. These types of networking relationships can occur from convenience or because cattle producers actively seek connections that are mutually beneficial to their ranching operation and to other businesses in their community.

Some potential networking partners for ranchers are suppliers such as veterinarians, lenders, feed suppliers, breeding companies, other ranches, and Extension personnel who can help improve production efficiency, cattle quality, or marketing. These partners may bring expertise and experience in areas such as range management, genetics, finance, nutrition, risk management, promotion, or cattle health. Cattle producers can also develop networking partnerships with their customers – including other cow-calf or purebred breeders, bull customers, feedlots, and even businesses closer to the end consumer such as local restaurants or beef supply chains.

Ranchers usually have choices of who will be their suppliers and where to sell their cattle or who to cultivate as customers. The ideal and most sustainable networking partnerships occur when both parties benefit; whether these relationships are between suppliers and the ranch or between the ranch and its customers. All these relationships require trust in order to be mutually beneficial. Trust is both a result and a cause of mutually beneficial networking partnerships in agriculture. Trust becomes a self-fulfilling prophecy in that ranchers whose businesses are improved by a relationship and who trust the network partner to balance that business’s interests with the rancher’s interests over both the short-term and the long-term will fulfill their side of the arrangement to the best of their ability. The outcomes of a mutually beneficial relationship for the rancher may be improved financial position, greater convenience, increased safety, enhanced business or health risk management, or enriched pride of accomplishment; and the supplier or customer reaps similar benefits.

An important networking partner for ranchers is their veterinarian. In a good, mutually-beneficial relationship, a ranch’s veterinarian should provide valuable services and should be able to be trusted to have the rancher’s interests valued as highly as his/her own interests. Veterinarians have the potential to provide advice and services that improve reproductive efficiency and that reduce the risk of production losses due to disease. Reproductive efficiency is an important driver on the income side of a ranch’s business ledger; and veterinary services such as selecting and developing heifers to ensure that they calve early in their first calving season, breeding soundness examination of bulls and monitoring cow body condition prior to the breeding season to protect against poor breed-ups, and utilizing biosecurity and vaccinations to guard against abortion-causing diseases provide the opportunity for mutually beneficial transactions.  In addition, losses due to disease, injury, or poisonings can negatively affect a ranching business through disrupted cash-flow, harmed relationships with customers, increased labor and treatment costs, and added family and employee stress.  Local veterinarians are knowledgeable and available to help minimize these risks.

When looking at the local community and beyond for potential networking partners, cattle producers should consider a few key steps in order to establish long-term, mutually beneficial relationships. The first step is obtaining the information you need in order to know if the potential partner is a good fit. If the business is local, you may have first-hand experience that gives confidence that the potential partner has the skills, financing, and ethics that will lead to a beneficial relationship for your ranch. If you don’t have first-hand experience, you should find out if suppliers, employees, and customers trust the business to provide quality service, pay bills promptly, and act fairly. Once you have identified a potential networking partner, it may be best to begin with smaller transactions that limit your financial and reputation risk; and to use smaller interactions to clarify the skills needed and responsibilities expected from both parties. Assuming that the association between your ranch and the other business appears to be mutually beneficial at the start, as more interactions develop over time, candid communication about what is working well for each party and where expectations are not met will be essential to create a long-term successful relationship.

In the end, forming successful long-term networking partnerships that benefit your cattle operation may take more time initially compared to less-thoughtful methods of selecting suppliers and customers; and may require communication, compromise, and change to maintain the relationship. But in the long run, finding the right partnerships can bring enormous benefits to any ranching operation in terms of efficiency, profitability, growth, and value to its customers.

Designing a Trichomoniasis (Trich) control plan to meet the specific needs of your ranch using Trich CONSULT

Bob L. Larson, DVM, PhD

Trichomoniasis (Trich) is a highly contagious disease that can cause cows to abort an early pregnancy when the organism is passed from infected bulls to cows during mating. This disease is very important to the cattle industry because infected herds experience very severe losses – commonly up to a 30% to 50% reduction in the number of cows calving. Infected cows and bulls appear healthy and it’s not until a high percentage of the cows are open at preg-check that Trich is suspected. While cows are usually able to clear the infection within a few months, females are occasionally longer-term carriers; and once bulls become infected, they will most likely remain a carrier for the rest of their life.

Trich has been reported in almost every state in the U.S., but some areas of the country have a much higher risk of coming into contact with a Trich-infected breeding animal than others. The movement of Trich into a non-infected herd is through infected bulls or cows. Any time a lot of cattle are moving from one part of the country to another, such as during a drought situation, the risk of spreading Trich to areas that did not previously have a lot of cases, is very possible.

Many states have imposed regulations requiring testing for Trich for bulls moved into their states, and some states have testing requirements for bulls moving within the state, and a few states have regulations about the movement of open cows. Rules about which animals must be tested for Trich before being allowed to cross the border vary between states, therefore you must contact the state where you are shipping cattle to in order to meet those regulations. In addition, in many states Trich is a reportable disease, therefore if Trich is diagnosed in a herd, the state veterinarian must be notified who will then start an investigation and control procedure.

Even though Trich is a very important disease to the U.S. cattle industry, most herds are not infected and many herds have a fairly low risk of becoming infected. Therefore, a Trich-control plan for a non-infected herd would be very different than a plan for an infected herd. For non-infected herds, the goal is to set up a system where it’s unlikely that Trich will be introduced from other herds. If you have a herd that is Trich-infected, an aggressive plan to test the bulls and to carefully manage the breeding season must start immediately after diagnosis is confirmed.

Trich CONSULT was designed for the beef industry as a free, user-friendly, online tool that helps cow-calf producers and veterinarians to minimize the effects of Trich in a herd that has been infected, and it can be used to design a system to keep Trich out of uninfected herd. The plans that are developed are customized to each herd’s specific situation through a series of questions and responses that is designed to mimic a conversation with a Trich expert. I’m a firm believer that one-size-fits-all Trich plans will not work. It takes a knowledgeable veterinarian who knows not only trichomoniasis but also the ranchers they are working with and their community to design the best individualized control and surveillance plans. The question and answer format of Trich CONSULT helps the cattle producer and veterinarian to cover all the important considerations when designing an eradication or prevention program.

Trich CONSULT is set up to provide different answers and follow-up questions based on previous answers. There are 6 to 10 questions in Trich CONSULT which should take about 10 to 20 minutes to complete, depending on each individual producer’s answers.  If you want more information about a particular question or answer, you can click on a “More Information icon” and get helpful feedback to help you make a decision that best fits your herd and management.

The first question in Trich CONSULT is, “Do you have trichomoniasis (Trich) in your herd?  The follow-up questions will be very different depending on whether you answer “yes” or “no” to that initial question. If you are not sure about your infection status, you will be asked several questions to determine whether or not it is likely that you have Trich in your herd. If you already have Trich in your herd, you will be asked whether you can do certain testing and management actions to find and remove potentially infected bulls and cows. Many of the suggested actions are very strongly recommended, while others are preferred, but if you are willing to accept some risk of continued Trich exposure the tool will provide advice about how to minimize those risks and establish a strategy to quickly respond if your risky decision resulted in negative consequences.

If you do not currently have Trich in your herd and want to create a cost-effective strategy to maintain your Trich-free status, you will be asked if you can implement several different barriers to allowing an infected cow or bull to come into contact with your herd. Again, some actions are very strongly recommended while other actions are preferred in order to have the lowest risk of disease; but if you choose to continue some actions that have slight to moderate risk of allowing Trich into the herd, advice is provided in Trich CONSULT to manage your retained risk.

After you have completed all the questions in Trich CONSULT, a report will be generated that includes the answers to all the questions that you just completed and a summary of the strengths and limitations of your agreed-upon strategy.

Trich CONSULT is located at www.trichconsult.org  and was funded by the Kansas StateVeterinary Diagnostic Laboratory, the Coleman Foundation for Food Animal Production Medicine at Kansas State University, and by USDA grant 2014-09684. The authors include veterinarians from Kansas State University, the University of Nebraska, Boehringer Ingleheim Vetmedica, Inc., the University of California at Davis, the University of Calgary, the University of Florida, and Auburn University.

Bull Management

Bob L. Larson, DVM, PhD

It is pretty obvious to state that bulls play a tremendously important role on cattle ranches. In the first place, obtaining a high percentage of cows pregnant in a controlled breeding season requires bulls that are fertile and have the ability and desire to mate cows and heifers that are in heat. It is also clear that the genetic makeup of a cowherd has a tremendous impact on profitability. In order to ensure that a bull is adding considerable value to the herd, he must fit within the herd’s genetic goals for low production costs and high demand for the offspring. The importance of the bull battery to the genetic profile of the herd is apparent when one remembers that this year’s bulls control 50% of the genes in the marketable product and that in commercial herds, greater than 90% of the genetic progress of a herd is via bull selection. Careful attention to selection based on predictions of genetic contribution to desirable traits, management to protect health, breeding soundness examination to remove bulls with questionable breeding ability, and appropriate bull-to-cow breeding ratios are required to optimize the investment ranchers make in their bulls.

According to a USDA survey, the two most common reasons that bulls are culled from commercial herds is because of infertility and physical unsoundness or injury. In order to address these risks, bulls should be thoroughly evaluated before each breeding season so that only bulls that are likely to be able to get a high percentage of exposed cows pregnant in a short period of time are turned out into the breeding pasture. The need for a thorough breeding soundness examination (BSE) is based on the fact that many prospective breeding bulls are infertile, subfertile, or unable to mount and breed successfully, and examination prior to the breeding season reduces the risk of breeding failure due to bull problems. The overall effect of BSEs is to eliminate many subfertile bulls and to improve the genetic base for fertility within the herd and breed. Although individual situations vary, national reports indicate that 10 to 20% of bulls will fail a thorough BSE (and another 10% that pass a BSE will perform poorly in the breeding pasture).

Because some bulls that have good quality semen and pass a physical examination still fail to successfully breed cows, it is necessary that bulls be observed closely during the breeding season. Because bulls that are not successfully mating have a tremendous negative impact on herd reproductive efficiency, every day (or nearly every day), producers should get bulls up and watch them walk and observe their underlines for indication of penis or prepuce problems in order identify lameness or injury that will prevent successful mating.

By using a thorough BSE to exclude questionable breeders before the breeding season starts and frequent observation during the breeding season to ensure successful mating ability, a relatively high cow to bull ratio can be used with the result that the number of offspring from superior sires is increased and the total bull-cost per calf weaned is decreased. The limited research that is available indicates that mature bulls with high reproductive capacity can be exposed to as many as 50 to 60 cycling cows in single-bull pastures (but fewer cows per bull in breeding pastures with multiple bulls). Young bulls should be exposed to fewer cows than mature bulls. For bulls less than three years of age, a commonly used rule of thumb is that a bull can successfully breed as many cows as his age in months (e.g. a 15 month old bull should be exposed to no more than 15 cows). The number of bulls required to adequately cover the breeding females is related to many factors. Environmental factors include: terrain, carrying capacity of the pasture, and pasture size. Bull factors include: age, condition, fertility, and social status. Social dominance of bulls is important to consider in multiple-sire breeding pastures. Several studies have shown that the most dominant one or two bulls in multi-sire pastures end up breeding a majority of the cows.

Although a high ratio of cows to bulls helps to reduce bull costs, it also exposes the herd to poor reproductive performance risk if the bulls fail to maintain good semen quality and quantity, or if bulls have reduced desire or ability to mate cows due to injury, illness, or low libido. Close observation of bulls during the breeding season is required in order to be assured that the bulls are getting cows bred. Injuries to bulls during the breeding season are relatively common. When a bull does become lame or incapable of breeding because of an injury to his reproductive tract, he needs to be removed from the breeding pasture and replaced by another bull.

Bulls need appropriate housing to provide protection during severely cold or hot weather – both of which can lead to temporary fertility problems. In addition, bulls should be maintained in good body condition throughout the year, becoming neither excessively thin nor fat. When developing bulls from weaning until they are turned out for their first breeding season, their diet should allow them to express full growth potential without becoming overly heavy. Restricting energy, protein, vitamins or minerals at any time between birth and maturity can delay the onset of puberty of young bulls and possibly reduce lifetime daily sperm output because of reduced testicular development early in life. Research has shown that bulls fed medium-energy diets from weaning to two years of age had greater reserves of sperm cells and higher quality semen than bulls developed on high-energy diets. In addition, young bulls grown at a rapid rate have a higher risk of bone and joint problems in their legs. This syndrome in bulls has also been described as leg weakness, degenerative joint disease, osteoarthritis, osteoarthrosis, and polyarthritis.

The two to three months leading up to the breeding season is an important period of time to ensure that bulls are in good shape to be “breeding athletes”. Exercise is important during the pre-breeding season period because during the breeding season the bull may travel several miles per day and maintain long periods of physical activity. If given ample area, bulls will usually exercise themselves. In designing bull facilities, it is a good idea to locate feeding and water areas as far apart as possible to encourage exercise. Bulls should have adequate body condition at the start of the breeding season so that weight loss during this period of high physical activity does not cause physiologic stress. At the same time, bulls should not be over-conditioned. If bulls are too fat, physical activity is reduced and excessive weight loss during the breeding season can occur. If bulls are in good body condition (BCS 5.0 to 5.5) then a forage-based diet with supplemental concentrate will be adequate to build the desired energy reserves. If the bulls are thin, then they may need substantially more concentrate feed.

Because bulls are so important for the genetic progress and reproductive efficiency of cattle herds; and because bulls account for a significant expense, excellent bull selection and care are critically important for optimum herd management. Bulls’ should be selected based on their ability to get a lot of cows pregnant early in the breeding season that will result in the birth of calves that will be high-value when they are sold. Once bulls’ are selected for the herd, they need to be fed to maintain good body condition and housed to protect them from injury risk. In addition, bull fertility and mating ability should be evaluated prior to each breeding season and monitored throughout breeding.

Role of your veterinarian in your business

Bob L. Larson, DVM, PhD
Beef Cattle Institute
Kansas State University

There are many people that impact the success of your ranching business, including your customers, your lenders, and your suppliers. One of the important suppliers for cow-calf producers is the local veterinarian. Veterinarians can provide important advice and service to improve ranch income, decrease costs, provide protection from losses due to disease, and offer options for marketing high-health cattle.

Ranch income is primarily derived from the sale of calves either at weaning for commercial operations or as breeding bulls or heifers for seedstock producers. Commercial ranchers can increase their income by increasing the pounds of calves at weaning and seedstock operations the number of marketable breeding animals from the same land and cow resources by increasing the reproductive efficiency of the herd. Veterinarians can provide advice and services to monitor and evaluate heifers, cows, and bulls so that a high percentage of the herd is able to successfully mate at the start of each breeding season.

Nutrition has an important impact on whether or not growing bulls and heifers reach puberty at an appropriate age and your veterinarian may be able to provide you with appropriate diets to meet targeted weight gain goals. Genetics also strongly influences whether developing bulls and heifers reach puberty by target ages, and your veterinarian is a valuable resource when considering selection and culling decisions. By doing breeding soundness examinations of bulls and heifers near yearling age, your veterinarian can help you identify the individuals that reach puberty at the time and with the amount of feed resources that you have identified to meet your ranch goals.

Doing breeding soundness examinations of mature bulls prior to the start of each breeding season allows your veterinarian to remove bulls that may fail during the breeding season due to foot or leg problems, other health problems, or reproductive tract problems. Although the reproductive tracts of mature cows are not routinely evaluated before the start of each breeding season, managing and monitoring the cows to confirm that a high percentage of the cows calve early enough in the calving season and in good enough body condition to resume fertile cycles by the start of the breeding season helps to ensure that herd reproductive efficiency will be high.

Monitoring body condition scores of the cow herd and rainfall amounts as predictors of future forage production potential allows your veterinarian to provide advice on a changing year-by-year basis to alter stocking density, timing of weaning, and supplementation strategies to ensure that cows enter the calving and breeding seasons in good body condition. The land base and herd size dictate much of the cost-side of cow-calf production and making sure that a high percentage of the cow herd becomes pregnant early in the breeding season allows those costs to be spread over a large number of marketable calves. By using body condition scores collected at several key points in the production cycle, your veterinarian can help you fine-tune the management of your herd based on the ranch forage-base, and the availability of cost-effective supplements or grazing alternatives, and the optimum cow size and milking ability for your herd. 

While every production year is expected to generate income from the sale of calves and to incur expenses associated with pasture and supplementation costs as well as cow depreciation and bull costs, significant losses due to disease is expected to be a rare event for cattle operations. Losses that are expected to occur rarely if at all but that could have a devastating impact on the financial status of a ranch if they did occur must be managed with cost-effective risk management strategies. Because disease losses do not occur every year, providing no defense may appear to be a sufficient and very low-cost management strategy in the short-run. However, over a longer time-frame, it would be very unusual for a herd with minimal disease protection to avoid devastating financial losses due to disease at some point in the future. Your veterinarian can provide valuable information about the likelihood that your herd could suffer losses from various diseases and the expected magnitude of those losses should your herd be exposed. By considering the likelihood of a disease, the magnitude of losses associated with that disease, and the effectiveness of available control strategies, your veterinarian can work with you to optimize the disease risk management of your ranching business.

Marketing of cattle, whether feeder calves or breeding animals, increasingly includes information about health status. When considering the optimum herd health program from a marketing standpoint, the risks that down-stream buyers face and their willingness to purchase from suppliers who can reduce that risk must be considered. For example, your herd may have very low risk for a disease and incurring expenses through diagnostic testing or herd certification may not reduce your herd’s already minimal risk; but the costs could easily be offset by customers willing to pay for that low disease risk. Increasingly, you must think of your down-stream customers as you work with your veterinarian to plan a health program that not only meets the needs of your herd but also provides a cost-effective marketing advantage.

A successful cattle business requires a combination of cattle and business expertise. Many successful ranchers count on a trusted team of advisors and suppliers to help them improve the profitability and sustainability of their ranching business. Finding and working with a local veterinarian who can provide assistance to increase income, control costs, and manage risks should be a goal of every cattle producer.