Category: Herd Management

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

An over-arching plan for optimum herd reproductive efficiency involves many important factors including heifer development, management of the mature cow calving and breeding seasons, and appropriate bull management. Because proper herd nutrition touches all these factors, it deserves special attention.   

In order calve at approximately 22 to 24 months of age and to reach puberty early enough to become pregnant before the start of the mature herd breeding season, heifers must reach puberty by 11 to 13 months of age. Beef heifers are expected to begin to have fertile cycles once they reach 50% to 65% of their mature weight. Developing heifers on a plane of nutrition (both energy and protein) from weaning to breeding that allows them to reach puberty by 11 to 12 months of age results in improved udder development and increased pregnancy rates.  But be aware that overfeeding heifers before breeding has also been demonstrated to have negative effects on the likelihood of becoming pregnant. A study showed that heifers that gained 1 to 1.5 pounds per day from weaning to the start of breeding were more likely to become pregnant during a 45 day breeding season than did heifers with gains above or below this range. Body condition scores (BCS) in the same group of 1,863 heifers showed the same result, with first-service pregnancy rates improving as body condition increased up to a score of 6 and then declining in fat heifers. In addition, excessive supplemental feeding of beef heifers before puberty has been shown to reduce lifetime calf weaning weights due to impaired milk production. This impaired milk production appears to occur in heifers that had high body condition and that deposited fat in the udder.  

Once puberty is attained, nutrition must be at a level that allows the heifer to continue cycling, produce healthy eggs, and establish pregnancy. Nutritional demands of heifers during pregnancy are greater than for mature cows because the heifer is using nutrients for her own growth as well as fetal growth. This increased demand for nutrients continues through early lactation, when the beef female has her highest nutritional requirements. Deficiency of energy or protein for extended periods of time during the first two and one-half years of life can have a negative impact on: fetal development, calf health, milk production, and rebreeding for the next pregnancy.  

Researchers have shown that heifers calving at greater BCS were more likely to be cycling at the start of the next breeding season and more likely to be pregnant during a 60 day breeding season. If heifers or cows are found to be thin during the middle third of pregnancy, increased nutrient intake for the three to four months leading up to calving can substantially improve pregnancy rate in the following breeding season compared to cows that calve in thin body condition. It is very difficult for cows to gain body weight 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 they should be evaluated for BCS three to four 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 two months to gain 2 body condition scores, they will need to gain over 3 pounds daily – a much more challenging task. 

The energy requirement for lactating cows averages about 20% higher than for dry cows (the actual requirement varies based on milk production), and this demand peaks at approximately 60 days after calving. This higher demand makes it difficult to add body condition once lactation begins. Because post-calving condition score and energy balance control ovulation, and being in good body condition is required for high pregnancy rates, both body condition at calving and level of nutrition after calving are important factors that influence pregnancy rates.  

Nutritional management of bulls is also important for bull fertility. Similar to the importance of how replacement heifers are managed from weaning to the first breeding season, how bulls are fed from weaning to their first breeding season greatly impacts their future physical soundness and fertility. Growing bulls should be fed so that they are able to express their full growth potential, and restricting energy or protein can delay puberty and possibly reduce lifetime sperm production. As with heifers, bulls that become too fat after weaning have been shown to be less fertile than bulls fed to gain appropriately from weaning to yearling age. Yearling bulls should probably be about a BCS of 6 and mature bulls should be BCS 5 to 6 at the start of the breeding season. In order to ensure that bulls are in good body condition, in the 60 days leading up the breeding season they need to have access to good quality forage and little to no concentrate supplement to maintain condition, and moderate to high amounts of concentrate if they need to add body condition.  

Proper nutritional management of growing heifers and bulls as well as timely assessment and management of mature cow and bull body condition are the foundations for an efficient and productive reproduction plan. Without a good nutritional plan, the best reproductive techniques and technologies will fail.  

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Innovations in cattle husbandry and health have been taking place since cattle were first domesticated for human use. For many centuries, our understanding of cattle health and productivity were only based on observations; and innovations were few and far between. The rapid changes in cattle health and productivity witnessed in the last 150 years have been made possible by increased use of carefully designed experiments and the adoption of the scientific method in the early parts of the 20^th century.  

Modern animal husbandry and health is based on a combination of art and science. The “art” component of cattle husbandry involves the practice of observing well. Innovations often come as a direct result of observing cattle over time and in many situations to become familiar with the range of behaviors that are normal, and being able to compare those cattle to others that exhibit different behaviors. The “science” component of cattle husbandry builds on the art of observing well, but then it goes further. It carefully measures not only the outcome of interest, but also other potentially biasing or confounding inputs so that important factors that change the risk of disease are not confused with other factors that don’t impact health or productivity.  

The United States has benefited tremendously from the establishment of Land Grant Universities starting in 1863. This innovation in higher education provided university professors with experiment stations to undertake practical agricultural research. The development of the Extension Service greatly increased the impact of plentiful applied research with the mission to promote research findings to farmers and ranchers. The Land Grant mission allowed for practical agricultural research to take place in every state of the union, and it came about just as the science world was learning how to do high-quality experiments that could identify subtle improvements while clearing away the clutter of variation due to weather, soil types, animal differences, and other factors that may or may not be important for a particular question. In addition, over the past 150 years, numerous animal health companies have developed extensive research facilities which add substantially to the number and types of innovations in agriculture.  

Some of the most important innovations in cattle health have come about in the areas of: vaccine development against common disease-causing viruses and bacteria, improved diagnostic tests to identify infectious agents and toxins associated with diseases of cattle, genetic tests to identify carriers of undesirable traits, antibiotics to treat and prevent diseases caused by bacteria, and chemicals to kill parasites such as worms, lice, scabies mites, and flies. In addition, innovative methods to use biosecurity principles such as quarantine, age-segregation, and sanitation have led to important improvements in animal health and productivity.  

The development of a systematic breeding soundness examination to evaluate bull fertility by combining a thorough examination of the bull’s overall health with a microscopic examination of semen and a thorough examination of the reproductive tract was an important innovation to minimize the risk of reproductive failure. Similarly, methods to accurately identify pregnant cows and to estimate the fetal age in order to predict breeding and calving dates has been one of the most important innovations to impact reproductive efficiency and herd productivity.  

Predictions of the impact of mating decisions on the performance of calves based on the performance of potential sires and dams, and their relatives (e.g. Expected Progeny Difference) has allowed rapid genetic improvement for many economically important production and reproductive traits. These tools to impact animal selection as well as other innovations in grazing management, forage supplementation, development of high-concentrate diets, and creation of growth promoters have increased beef production on diminishingly available agricultural land in the U.S.  

Even as the innovations of the past 150 years are celebrated for their impacts on the health and productivity of beef cattle, the potential for future innovations holds equal promise. Some of the innovations we may see in the near future include: genetic markers for animals with particularly good (or poor) immunity to disease, genetic markers for highly fertile bulls and heifers, improvements in vaccine, parasite control, and antimicrobial products, and increased use of biosecurity tools such as carefully controlled herd/pen size, age-segregation, treatments to clear cattle that are persistent carriers of infectious agents, and quick, chute-side diagnostic tests for many disease agents and production characteristics. 

No discussion of innovation would be complete without an acknowledgement that not all innovations stood the test of time. Some reasons that exciting innovations are introduced only to quickly fade away include: other factors playing a bigger role in disease or production than the one we are targeting with innovative technologies or management, microorganism adapting to the pressure of new technologies and becoming much less susceptible to a promising innovation, side-effects such as toxicities or unforeseen consequences outweighing the benefits of the innovation, or changes in management (human behavior) that reduce existing problems while leading to the emergence of new problems.  

The causes of disease and production limitations are very complex. New knowledge and innovations can allow veterinarians, cattle producers, and researchers to attack some of these causes to limit the extent or timing of negative effects, but it is highly unlikely that we will ever be able to reduce the effect of all negative factors simultaneously. However, looking at the history of innovations in the cattle industry as a guide, if we maintain a holistic view to create and maintain a sanitary environment, balance nutrients as needed, reduce stress, and identify and remove disease reservoirs where possible, we have reason to be certain that more exciting innovations are in our future.  

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Both calves and cows have a number of health risks around the time of calving. Of course, cattlemen and veterinarians recognize the risk to calves during and after a difficult birth; but is it also important to recognize that cows are at risk from several important complications following calving.  

Lacerations – The reproductive tract can be torn during delivery, particularly if the calf is large or positioned incorrectly. Tears of the external reproductive tract occur when the vulva does not have time to stretch prior to delivery. Many times, if the tears are discovered quickly, they can be sewn together immediately. If a tear of the vulva is not discovered until it has started to swell, it is best to wait until all the inflammation is gone before correcting. Tears in the vaginal tissues are fairly common and it they don’t result in obvious bleeding may go unnoticed. There are some large blood vessels at the 2:00 and 10:00 positions of the vaginal birth canal, and if these are torn the situation can become an emergency. Occasionally a vaginal tear is identified when a mass of fat protrudes from the vulva. If a vaginal tear is discovered soon after calving, it can be corrected with a simple surgery. Because many vaginal tears are not detected soon after they occur, they may be first suspected when hard masses are palpated in the vaginal area during a rectal examination. Whether or not a vaginal tear leads to an infection or abscess that causes fertility problems depends on the size and location of the tear and the potential to correct the lesion.  

Tears of the cervix and uterus are very difficult to treat and surgical repairs are rarely attempted. Tears in the uterus and cervix are usually due to improperly handled difficult calvings when excessive force is used to pull a large or malpositioned calf. The severity of a tear depends on how large it is and where it is located. In some situations the abdomen can become contaminated which can lead to severe illness or death.   

Uterine Prolapse – A prolapsed uterus occurs when the uterus is pushed outside the abdomen after delivering a calf – leading to an emergency situation. Most uterine prolapses occur immediately after calving but it is possible for a prolapse to be delayed for up to several hours. Prolapse of the uterus is often associated with pulling a large calf. Cows that are in poor body condition or that are consuming a diet with mineral imbalances are at greater risk for this condition. A prolapsed uterus must be corrected as soon as possible in order to prevent severe bleeding and shock and to save the life of the cow.  

Retained Placenta – The placental membranes are normally expelled within two to eight hours after birth. Occasionally, however, they fail to separate from the uterine attachments. Although retained placenta is rarely a life-threatening problem in cattle, it can lead to uterine infections and failure to become pregnant in the next breeding season. Not all reasons for retained placentas are known, but a herd with a more than an occasional retained placenta may have a disease or nutritional problem that should be investigated further. 

There are differing opinions as to the best treatment for retained placentas. Research has shown that pulling on the placenta can cause more problems than it solves. For cows with a good appetite and no signs of abnormal vaginal discharge, it is probably best to continue to wait without treatment. Treatment with an injectable antibiotic is reasonable if a retained placenta leads to uterine infection. 

Calving Paralysis – This condition is much more likely in heifers than in cows. The nerves that control the dam’s back legs can be damaged in a prolonged dystocia or if a calf becomes hip-locked. The condition may affect one or both rear legs. If the cow is down and the calf is hip-locked, the down leg is the one most commonly and severely affected. If paralysis is severe and affects both legs, the heifer or cow may not recover. If a cow is not able to rise and stand without assistance within 48 hours of calving, the likelihood of recovery starts to become doubtful. The chances for recovery after 2 to 3 weeks are very poor, and euthanasia may be recommended. The only treatments for calving paralysis are good nursing care and assisting the cow to stand several times a day through the use of a sling or hoist. The down cow should be kept in a well-bedded stall or pen, preferably with a sand or dirt floor.  

Prevention strategies for all of these post-calving problems are focused on reducing the risk and severity of calving difficulty through: selection of appropriate calving ease bulls to breed to heifers, proper nutrition during late gestation, and effective and timely intervention when a birth does not proceed normally. When these post-calving complications do occur, you must work closely with your veterinarian to begin appropriate treatment to protect the health and life the affected heifers and cows.  

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

While veterinarians and cattle producers work long and hard hours to protect the health of the cattle in their care, sometimes euthanizing an animal is the best way to protect cattle welfare. A decision to euthanize an animal is based on the level of pain or distress of the animal, how likely the animal is to recover and the length of time required to recover if treated, the ability to get to feed and water, the likelihood that the animal would be condemned if presented for slaughter, and the potential for important diagnostic information to be gained that would protect the health of other animals or humans.  Conditions that may indicate that euthanasia is appropriate to protect animal welfare includes situations when an animal has a severe injury such as a fracture that prevents them from standing, situations when the animal has poor quality of life due to advanced age or disease (particularly with a low likelihood of recovery), disease conditions with no effective treatment or that produce a high level of pain that cannot be managed, diseases for which the treatment would result in extended drug withdrawal time until clearance of tissue residue, or diseases such as rabies that involve a significant threat to human health.   

The goal of euthanasia, as described by the American Veterinary Medical Association is to use “a method of killing that minimizes pain, distress, and anxiety experienced by the animal prior to loss of consciousness, and causes rapid loss of consciousness followed by cardiac or respiratory arrest and death”. Basically, euthanasia is the practice of ending the life of an ill or debilitated animal in as painless and low-stress manner as possible. Each approved method of euthanasia will either involve direct destruction of brain tissue (gunshot, penetrating captive bolt), rapid onset of unconsciousness (non-penetrating captive bolt or anesthetic drug) followed by cutting a major artery to remove oxygen-carrying blood, or use of a drug (barbiturates) that directly depresses the brain which leads to death by the stoppage of breathing. Because cattle are large and euthanasia options, by their definition, have the ability to end life, human safety is a primary concern when selecting a method of euthanasia. 

Several of these euthanasia techniques require that the animal be restrained in a squeeze chute or in a similar manner; if restraint is not possible, it is likely that only gunshot to the head is practically possible, and it requires specialized skill and training. If performed skillfully, gunshot induces unconsciousness instantly and does not require close contact with the animal (2 to 10 inches from the head). However, this method should only be attempted by individuals trained in the use of firearms and the proper location of the point of impact for euthanasia, and who understand the potential for ricochet. Care must be taken to minimize danger to the shooter, to bystanders, and to other animals. In addition, the shooter should be aware of local ordinances that may prohibit the discharge of firearms in some locations.  

Captive bolt “guns” are placed firmly against the skull (training is required to identify the correct location) of a restrained or sedated animal. The bolt is either penetrating or non-penetrating depending on the gun type. Both types (penetrating and non-penetrating) will consistently cause stunning of an animal. A stunned animal will “drop” but will still exhibit respiration and sudden quick limb movements. These movements may be misinterpreted as a response to pain by a person inexperienced with euthanasia. An additional procedure such as cutting a major artery such as one or both carotid arteries in the neck, the major arteries located under the front legs, or the aorta to allow the animal to bleed-out or injecting a chemical agent to stop breathing must be used to ensure death after the use of the non-penetrating captive bolt and is recommended after use of the penetrating captive bolt. The captive bolt method may not be appropriate if the euthanasia will be observed by people not trained in the method.  

Injecting an overdoses of a barbiturate drug into a large vein is an effective method of euthanasia, but requires a special veterinary license. When properly administered, barbiturate overdose produces rapid unconsciousness followed by slowing and then stopping of breathing and a heartbeat. This method is particularly appropriate if untrained people will be observing the euthanasia because of the minimal movement of the animal after injection, or if the animal is being euthanized because of concern that the animal may have rabies. In order to test for this important disease that can affect humans, the brain must sent to a diagnostic laboratory and euthanasia methods that destroy the brain (gunshot and captive bolt) cannot be used. One drawback to this method of euthanasia is that carcass disposal options may be reduced. Because tissue residues of the barbiturate can be high, renderers may not accept the carcass and if disposal methods such as composting or shallow burial allow scavengers to gain access to the carcass, unintended animals or birds (some which are protected by federal or state law) may be killed. Remaining options for carcass disposal are limited by state and federal regulations, but may include deep burial or incineration.  

Euthanasia of an animal that is suffering from irreversible disease or injury is a primary responsibility for cattle producers and veterinarians. While an important component of animal care, this practice is not simple because potential methods of euthanasia each have their limitations. Cattle producers will occasionally be confronted with ill or debilitated animals that should be humanely euthanized. This important task should be done by people with the skills and training to maintain human safety as well as to ensure a quick and painless death of the animal. 

More information available from: Practical Euthanasia of Cattle: Considerations for the Producer, Livestock Market Operator, Livestock Transporter, and Veterinarian. Prepared by the Animal Welfare Committee of the American Association of Bovine Practitioners (available in both English and Spanish). http://aabp.org/about/AABP_Guidelines.asp 

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Johne’s disease is gaining greater attention among beef cattle producers and veterinarians who work with beef cattle. Johne’s was first described in Germany early in the 20^th century and is caused by the bacteria Mycobcterium paratuberculosis (which is related to the bacteria that causes tuberculosis in humans). The disease is usually spread to young calves through contact with infected manure or milk but infected cattle don’t show signs of the disease until several years later. The disease is more common among dairy herds compared to beef herds, primarily because dairy production is more confined with greater potential calf exposure to the manure of adult cattle, but can be a problem in some beef herds particularly herds marketing replacement bulls and heifers. 

Johne’s is primarily a disease of cattle, but can affect other ruminants such as sheep, goats, and even deer. The organism invades the small intestine and grows very slowly. Over time the organism spreads and infects more of the small intestine until enough of the intestine is thickened to cause diarrhea and weight loss even though the animal is eating well and behaves normally. Early in the disease, very few of the organisms are shed in the feces but as the infection involves more of the intestine, the animal sheds increasingly more of the bacteria in the manure. Older animals are fairly resistant to infection with the organism, but young calves are susceptible.  

Calves most commonly become infected during suckling by contact with their dam’s feces or the feces of other cows on their dam’s udder. The organism is also present in the colostrum and milk of heavily shedding dams. The younger the animal and the higher the dose of bacteria that the animal swallows, the greater the likelihood that the calf will become infected. In addition to swallowing the organism from contaminated teats or from colostrum or milk, the organism can also pass from the dam to the fetus during pregnancy. Cows that are in late stages of the disease (obviously losing weight and having diarrhea) will pass the organism to 20% to 40% of their calves during pregnancy and about 8% of calves from cows in early stages of the disease will be born with the infection. The bacteria that causes Johne’s can live in the environment for up to a year and manure contamination of clothes, boots, and equipment could also move the agent from one farm or ranch to another or from one part of a farm or ranch to a distant part. 

The economic loss of Johne’s in beef herds is fairly low at this time. A few animals will die or be so emaciated that they are condemned if presented for slaughter. Of greater potential economic impact is buyer perception of the importance of Johne’s disease. In the future, cattlemen may place great importance on purchasing cattle only from herds at low risk for Johne’s, and producers with infected herds would find the value of any bulls or heifers offered for sale to be discounted, and producers with low-risk herds would find the value of their animals increased.   

The difficulty in controlling Johne’s disease is that our current tests are only accurate fairly late in the disease process when the slow growing bacteria have reached a high enough population to be readily detected. We don’t have accurate tests for young cattle, so that infected cattle can stay in the herd shedding the organism at low levels into the environment before they can be detected, and young animals that are already infected are likely to test negative and can be purchased even though an effort is made to exclude test-positive replacements. No treatment is available to cure Johne’s in cattle. The only way to rid a herd of the organism is to identify infected cattle and remove them as soon as possible and instituting control methods to prevent infection of new young replacement stock. 

Voluntary control programs to minimize the risk of Johne’s have been implemented in some U.S. dairy herds. Those control programs focus on finding cows that shed a lot of Johne’s-causing organisms (our current tests are pretty good for this task) and removing them and their offspring from the herd. Also, efforts are focused on sanitation for the young calf – minimizing contact between young cattle (<6-12 months of age) with manure from adult animals and the milk and colostrum of cows other than their own dams. Efforts are also focused on preventing the introduction of possibly infected cattle into a herd by eliminating the introduction of replacement cattle from unknown sources (such as leasing bulls, purchasing nurse cows) and eliminating practices such as fertilizing pastures with manure from another farm.  

In general, beef herds should not obtain calves or colostrum from dairy herds unless the dairy herd is involved in a Johne’s control program and is at low risk for the disease. Beef producers should also cull any animal with chronic diarrhea and any of that animal’s offspring who are in the herd – even if the cow is pregnant. A strategy to improve sanitation and place constraints on animals entering the herd will help prevent many other diseases besides Johne’s. 

In addition to these baseline controls, some purebred herds follow testing guidelines approved by the National Johne’s Working Group (NJWG) and national U.S. Animal Health Association (AHA). In part, these guidelines recommend initially testing 30 females (three years and older) utilizing an ELISA blood test. Statistically, if all of those cows test negative you can be 85% sure that the herd does not have any Johne’s-infected cows. The NJWG guidelines recommend follow up procedures to further document a herd’s low-risk status over time.  

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Veterinary medicine and cattle production have a long and shared heritage. I imagine that as people first started domesticating cattle to provide meat and milk, certain individuals had a particular interest in their health and well-being. Historical artifacts from as early as the Bronze Age indicate that there have long been people who were called upon to provide their expertise in the care and health of animals. The first known veterinary college was established in Lyon, France in 1761 and the first schools that focused on veterinary medicine in the United States were started in the middle to late 1800’s. Since the beginnings of veterinary medicine, the profession has been influenced by the contemporary theories and practices of human medicine and livestock production, and has a unique position at the intersection of medicine, animal health, and food production.  

Both in the past and currently, veterinarians have been responsible for identifying and treating individual cattle that become ill or injured. In addition, because cattle are often grouped into large herds, the health and well-being of herds and even multiple herds within a region has also been emphasized. The important role that cattle play in human health is based on the part that cattle play in providing meat and milk as sources of high quality protein and other essential nutrients. Cattle health also impacts human health because of some shared diseases such as brucellosis and tuberculosis.  

Veterinary medicine has had important roles to play in the establishment, growth, and maintenance of the U.S. cattle industry. Shortly after the Civil War, the early cattle drives from Texas to railheads where cattle could be shipped to the cities of the eastern U.S. almost came to an early end because of Texas Cattle Fever, a disease carried by ticks that could pass from the resistant Longhorn cattle to the susceptible cattle farther north and east. By establishing an early form of quarantine that effectively separated tick-carrying cattle from other cattle, railheads were established in Kansas towns such as Abilene, Ellsworth, Wichita, and Dodge City largely because they were located away from established herds and farms. Because of the importance of Texas Cattle Fever, in 1893 the Texas Legislature created the Livestock Sanitary Commission with the goal to eradicate the Texas cattle fever tick. Other state and federal programs to target and eliminate important diseases of cattle followed, with an official program of the federal government to eradicate bovine tuberculosis starting in 1917 and the federal brucellosis program starting in 1934. These successful federal efforts built upon the work started by cooperating veterinarians and cattle producers at local and state levels.  

Because of their training and experience dealing with diseases that cause illness, death, abortion, and production inefficiency, veterinarians have long been looked upon to diagnose and treat cattle that are noticeably ill. In addition, veterinarians focus on preventing disease and injury through animal management, nutrition, vaccination, quarantine, and parasite control. Veterinarians are also actively involved in optimizing reproductive efficiency through skills and services focused on heifer development, breeding season management, reproductive examinations of bulls, and prevention and treatment of calving difficulty.  

While many of the roles that veterinarians play today are exactly the same as the roles of animal health providers through the centuries, new roles are appearing. Veterinarians have increasingly important responsibilities for beef quality assurance (BQA), antimicrobial stewardship and cattle welfare. Because of the close relationships that veterinarians have with cattle producers as well as their responsibilities for animal health and public health, veterinarians continue to have a unique position in society to serve the interests of cattle producers, the cattle themselves, food consumers and the wider public.  

It is important to occasionally look back in time to appreciate the heritage that we all share in the cattle business, and the extraordinary people and situations that worked together to create the beef industry we have today. In addition, we look for lessons in the past as we address new problems and opportunities in cattle production and veterinary medicine as we plan for the future. 

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Salmonella is a well-known family of germs that causes disease in both humans and animals. In beef herds, salmonella is not a common cause of scours in calves; but it is important because it can be associated with high death loss and this disease may be transmitted to humans. Both adults and calves can become sick due to salmonella, but calves are usually more commonly and more severely affected.

Although there are over 2,200 known types of salmonella, only a few are associated with disease in cattle, and two types of salmonella account for most cases of disease in U.S. cattle herds. The two types usually result in different signs of disease.  

Salmonella typhimurium is often highly fatal to calves, but this type of salmonella does not usually persist in carrier animals. Therefore, deaths and disease due to this organism are usually sporadic (likely to subside after an outbreak). Another outbreak of S. typhimurium is only likely if a source of infection (infected rodents, contaminated feed, etc.) is re-introduced to the cattle. Diarrhea and fever are the most common signs of illness in calves infected with S. typhimurium, but the disease can progress to pneumonia or infections of the joints, nervous system, or other body parts. Humans that are young, old, or immune-suppressed are at risk to get Salmonella from these sick calves. 

Salmonella dublin is also highly fatal but the calves may not have diarrhea. These calves may show signs of depression, pneumonia, infection of the nervous system, joints, or bones. S. dublin is a long-term problem for a farm because the organism tends to persist in some cattle without showing signs of disease. These carrier animals are a constant source of the organism to infect new calves. This form of Salmonella is rarely passed to humans.

Calves that are scouring due to Salmonella usually have a fever and the manure is bloody. Because these signs do not usually appear when diarrhea is caused by rota virus, corona virus, or K99 E.coli, veterinarians and producers can often identify cases that are likely to be caused by Salmonella.

Direct sunlight kills salmonella organisms, although it is able to survive in soil, manure, and drinking water up to 7 to 10 months. Mammals, birds, reptiles, and insects can become infected with salmonella and carry it onto your farm or ranch. Some feedstuffs such as fishmeal can be contaminated with salmonella from the source animal, and infected rodents or birds can contaminate feed with their droppings. 

Salmonella almost always enters a calf through the mouth and the severity of disease is often related to the amount of exposure due to crowding, unsanitary conditions, or amount of contamination of feedstuffs. Cattle may be exposed to the disease in several ways, including: animal-to-animal (from dam to calf, or calf to calf), by contaminated feed, or by a contaminated environment (soil, birds, rodents, insects, water source, etc.). 

The amount of stress an animal is facing also affects the severity of salmonella infection. Feed and water restriction (usually due to shipping), recent calving, changes in the diet, exertion, anesthesia, surgery, and presence of other disease can all cause a carrier (or sub-clinical) animal to start showing signs of infection, or can make an animal exposed to salmonella organisms in the feed or environment more susceptible to disease. Giving antibiotics by mouth to treat salmonella is usually not recommended because these products can kill the normal bacteria in the digestive tract that compete with salmonella organisms. Protection for calves relies on adequate consumption of colostrum in that calves on a farm with a salmonella outbreak that did not receive adequate protection from colostrum are at great risk of disease.

Treatment of salmonella cases involves prolonged use of oral and often intravenous (into the vein) electrolyte solutions. Because the calves tend to lose weight and body mass quickly, frequent feedings with small quantities of milk is also advised. Treatment with systemic antibiotics (those given into the muscle, under the skin, or into a vein) for a few days early in the disease will probably be helpful, but will not cure carrier animals. Only antibiotics that are shown to be safe and effective for Salmonella cases, and that are approved to be used in food animals, should be used in scouring calves.    

The keys to preventing salmonella are to decrease stress and enhance sanitation. The calving and nursery environment should be as clean as possible and feed should be protected from contamination from the manure of other cattle, rats, birds, and other animals. 

Because people can become infected with salmonella, it is always wise to wash your hands thoroughly with soap and water after you take care of cattle or handle manure. You should also wash your clothes and boots frequently to help prevent spreading salmonella to other family members. When dealing with scouring calves, it is important to let as few people as possible handle the sick calves; and to have people treating calves change their clothes and boots when they are finished with treatments. 

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Every cattle producer has the goal to efficiently utilize available forage, labor, management, and financial resources to produce cattle that will meet customers’ expectations and desires. Outbreaks of disease that result in sickness, reduced reproductive or growth efficiency, or death not only negatively affects animal welfare but also will drastically reduce the efficiency of saleable production from the available resources. Protecting the health of cattle herds is an important part of a successful plan to have a profitable and sustainable ranching operation. Besides a veterinarian’s value in diagnosing and treating cattle that become sick, he or she can have great value in preventing disease and ensuring optimum production in beef cattle herds.  

A complete health plan should be established between veterinarians and producers that accomplishes at least the following goals: 

1. Establish a biosecurity plan to minimize the introduction of disease-causing germs onto your farm by developing a testing and isolation plan for new or returning cattle, a vaccination protocol, and a traffic flow and visitor restriction plan to reduce the likelihood of infectious disease.

• New cattle (including new bulls, replacement heifers and cows, and purchased calves) should be isolated away from the herd for at least one month. During this time the new additions should be vaccinated to bring them into the same protocol as the resident herd and may be tested to determine if they are carriers for diseases of importance to the herd. If at any time during the quarantine period the incoming cattle exhibit signs of diarrhea, lameness, respiratory disease, excessive tearing or eye lesions, rough skin or hair loss, or any other sign of disease, a veterinarian should be called to examine all the animals in the group and the quarantine period extended.  
• Every herd should have a sound vaccination protocol based on consultation with your veterinarian that is appropriate for your specific risk factors. In most herds, cattle will be vaccinated with one or more products at several times during the year. Calves are routinely vaccinated against clostridial diseases such as blackleg when they are still nursing. Vaccinations, before or at the time of weaning, are implemented to develop immunity to reduce the risk of respiratory disease. Replacement heifers and yearling bulls deserve special attention prior to the start of their first breeding season to establish strong immunity to diseases that cause reproductive loss. And vaccinations of adult cows and bulls are implemented to reduce the risk of infectious disease that can cause abortions.  
• When implementing a vaccination protocol, it is important to handle and administer the products according to label instructions in order to ensure their greatest effectiveness and compliance with beef quality assurance guidelines. For example, if a vaccine is labeled for use Sub-Q (under the skin) administration, it must be administered under the skin in the neck region. If a label indicates that the product should be given in the muscle, it should be given in the neck muscles. Do not vaccinate into the rear leg of a calf or cow. 
• Part of biosecurity is to minimize the spread of germs that are already on a ranch so that least amount of disease occurs. A plan to keep young calves and pregnant cows away from cattle imported from other operations (such as stocker cattle or incoming replacements) and away from fence-line contact with other herds will decrease the risk of devastating disease outbreaks. 

2. Establish a sanitation plan to minimize the potential for spread of disease-causing germs in manure between animals in calving and nursery pastures, in feeding areas, and by means of feed handling equipment (front-end loaders, feed wagons, etc.).  

• The germs that cause diarrhea diseases (scours) can be passed in manure from one animal to another. Therefore it is very important that young calves are born and housed in the cleanest situation possible. Strategies to improve sanitation for young calves include avoiding calving in the same pasture where cows were fed all winter and selecting calving pastures that: are large enough for cows to spread apart, have some natural or man-made shelter, and are not in a low, or mud-prone area. In addition, I prefer to avoid using bale-rings in calving and nursery pastures – spread the hay and move the feeding location daily. 
• To prevent scours, two important goals are to avoid exposing calves less than three weeks of age to mud and to older calves. Grouping cow-calf pairs so that all the calves in a nursery pasture are as close in age as possible will greatly reduce the risk of scours. The Sandhills calving system capitalizes on this strategy to ensure sanitation and segregation from older calves so that calf health is optimized. 

3. Establish a parasite control program to effectively use de-wormers and pasture management for internal parasite control, and establish the use of sanitation and fly and lice control products to minimize economic loss due to external parasites. Calves and yearlings have much less natural resistance to internal parasites than adult cattle, therefore cattle less than two years of age deserve special attention.  

4. Establish a program to optimize the use of performance-promoting products such as growth-promoting implants and ionophores in growing cattle. Ionophores create an environment in the rumen that favors the growth of microbes that more efficiently convert forages and grains into energy. These products also inhibit the parasites that cause coccidiosis.  

5. Establish a program to minimize calving difficulty in first-calf heifers by proper replacement heifer selection, nutrition, and sire selection. Replacements should be selected from heifers born in the first 40 days of the calving season to excellent dams and desirable sires. From weaning until breeding at a little older than one year of age, replacement heifers should receive high quality forages or supplements in order to ensure that they gain enough weight to reach 60-65% of their mature weight prior to the start of their first breeding season. Heifers should be bred to calve a little ahead of the mature cow herd to allow them to receive extra attention during calving and because first calf heifers take longer to resume fertile cycles after calving than mature cows. Heifers should be bred to bulls with EPDs indicating calving ease and they may need supplementation during parts of the year in order to reach a target of 85% of their mature weight at the time of calving.   

6. Establish a method to evaluate the herd’s performance (records) in the areas of: pregnancy rates, death loss, growth (weaning weight) and nutritional needs (body condition scores). Traditionally, the herd is evaluated at the time of calf weaning to identify the number of calves weaned per cow exposed for breeding, the percentage of the cow herd that became pregnant in a controlled breeding season, and the body condition of cows that completed lactation on the available forage. This is also an ideal time to closely observe cows for problems such as cancer eye, mastitis or other udder or teat problems, foot or hoof problems, or any signs of disease.  

7. Establish disease treatment protocols for the herd as well as proper injection sites, injection routes (sub-Q, intra-muscular, intra-venous, etc.), dosages, and any withdrawal times to be observed. The privilege and responsibility to use antibiotics, vaccines, dewormers, insecticides, estrous synchronization hormones, and other products appropriately is important to everyone in the cattle industry. To evaluate the best available products and procedures, the herd veterinarian and producer should routinely meet to update disease prevention and control strategies.  

While specific herd health plans will vary between ranches, all producers should start by ensuring that their plan meets the seven goals listed above. By working with your veterinarian to meet these goals, the costs of disease and production loss can be minimized and animal welfare enhanced.

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Pinkeye is a painful eye disease that is found throughout the world. This disease is more common in cattle with light-colored faces and in situations with bright sunlight, dust, and certain other environmental conditions. Herd outbreaks of pinkeye may occur at any time of the year, but the risk is highest during the summer months.  

The germs causing pinkeye generally follow a minor eye injury caused by bright sunlight, dust, wind, tall grass or weeds, plant seeds, pollen, face flies, or diseases such as bovine rhinotracheitis (IBR). If these insults are not followed by an infection with pinkeye germs, the animal will only have a short period of irritation as evidenced by excessive tearing. In contrast, if injured eyes become infected, serious problems can result. A veterinarian may need to examine affected cattle to determine whether an eye problem is due to pinkeye or another disease. 

Several different organisms cause pinkeye infections; the most common being Moraxella bovis. This germ has hair-like structures which allow the organism to become attached to the surface of the eye. In addition this bacteria produces an enzyme that destroys cells on the eye’s surface. Moraxella bovis can be transmitted to other cattle by direct contact with eye discharges or may be carried from one animal to another by face flies. Face flies are involved in the spread of pinkeye because they are very irritating to the eyes of cattle, making them more susceptible to infection, and they pick up the organism while feeding on the face of infected animals and can spread it to the eyes of other cattle as they move through a herd. Calves are believed to be more susceptible to pinkeye than older animals partly because they have not developed immunity and also because their eyes are physically closer to dust, pollen, and tall grass or weeds.  

Generally it is believed that cattle that have been infected with a particular type of Moraxella bovis will not develop the disease again for more than a year. However, there are various types or families of this germ, and immunity to one type does not mean the animal is immune to the other types of the organism. In addition, other germs can cause pinkeye infections, and immunity to previous Moraxella bovis infections will not protect against these infections.  

The earliest sign of pinkeye is increased tearing which appears as excessive wetness around the eyes. When examined more closely, the inside lining of the eyelid and the white portion of the eye will appear red, and then as the disease progresses the eye becomes cloudy or white. An ulcer often is formed in the center of visual portion of the eye and if the ulcer it is deep enough, the eye can rupture. Without treatment, many animals will heal in 3 to 6 weeks. Some animals heal with no evidence of previous problems, while more severely affected individuals will have a white scar on the eye surface that may fade over time. Eyes that have ruptured will become blind and extremely disfigured. 

Treating cattle with pinkeye with injections of antibiotics and reducing exposure to dust, weeds, and sunlight is the best method of treatment. Most strains of Moraxella bovis are susceptible to antibiotics that can be injected under the skin of the neck. Covering the eye with a patch glued over the face or by sewing the eyelids shut will help to make the animal more comfortable by decreasing sunlight exposure and it helps to decrease the spread of the disease.  If possible, affected calves should be moved to shaded areas (to avoid direct sunlight) with no dust and where they can be easily treated. Of course, the calves and their dams should be provided with adequate feed and water until they can be turned back out with the rest of the herd once the eyes have healed. 

Prevention and control of pinkeye involves reducing exposure to environmental risk factors such as dust, pollen, and tall grass and weeds through pasture management, reducing face fly burden through use of chemical pesticides, and by isolation of affected individuals from the rest of the herd. 

The fact that animals appear to be immune to M. bovis following recovery after an infection and that older animals have a higher level of natural immunity, would lead one to believe that vaccination would provide an effective method of prevention. However, use of vaccines to prevent pinkeye disease has not been particularly successful. Although these vaccines have been shown to be partially protective, they may not be completely protective due to the ability of Moraxella bovis to change type, the presence of other organisms, or environmental factors that allow the organism to overcome the animal’s immune system. 

Pinkeye is a frustrating disease because ranchers can go many years without problems, and then they can have a year where a high percentage of calves are affected – even though no apparent changes have taken place. Although vaccines are commonly used to help protect against the disease, there are a number of factors that work against this being a highly effective strategy. Treatment of pinkeye cases requires a lot of labor usually at a time when calves are on pasture and difficult to capture individually. Although no simple solutions are available, a commitment to: good pasture management, effective fly control, and early detection and treatment of eye problems is the best strategy to minimize the effects of this disease. 

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Tall fescue is a commonly grown forage for cattle, particularly in the southeastern and lower midwest states, as well as the Pacific northwest. This grass originally came from Europe and was discovered growing in a few isolated stands in the U.S. in the early 1930’s. It was recognized as being easy to establish with a long growing season, resistant to drought and insects, and able to grow on many types of soil. However, it was soon discovered that cattle performance was negatively affected by the grass. 

Today, we know that a high percentage of tall fescue pastures are infected with a fungus that grows inside the plant (so it is not visible to the eye) and the fungus produces a number of chemicals that provide both the positive and negative attributes of the grass. Not all fescue pastures are infected with endophyte fungus, and the percentage of plants in a given pasture that are infected will vary from one pasture to another. Generally speaking, the greater the percentage of plants infested with the fungus in a pasture, the greater the negative effects of fescue toxicosis. Although the fungus is found throughout the tall fescue plant, it is found in the highest concentration in the seed head and stems with lesser concentrations in the leaves. The fungus can be spread to un-infected pastures if infected seeds blow or are transported to bare ground where it can become established. 

Cattle grazing heavily infected stands will consume less grass, gain less weight, and have lower pregnancy rates than cattle grazing other types of forage. Cattle with fescue toxicosis syndrome are often recognized by having a rough, long haircoat and being thin. In addition, severely affected cattle will have high body temperature, and they will attempt to cool themselves by standing in water and seeking shade. Blood flow to the feet, tail switch, and ears is reduced, and in cold weather, affected cattle can slough the ends of their tails and the tips of their ears and in some cases, even the hooves can slough. 

Cattlemen with infected tall fescue pastures have a number of options. In many situations, because of fescue’s positive properties, they may choose to live with it and work to reduce the negative effects by inter-seeding legumes into the pasture to dilute the intake of fescue. In addition, if other types of forage are available, cattle can be moved off of infected pastures during the summer months when the effects are most severe. If fescue is grazed heavily so that the plants are kept short, less endophyte fungus will be present in each bite of grass. Grain supplementation also acts to dilute the amount of endophyte consumed. Cows fed grain along with highly infected fescue hay had reduced winter weight loss and improved pregnancy rates compared to cows fed infected hay alone.

Some producers may decide to invest the resources necessary to avoid the endophyte completely by replanting infected stands of tall fescue with non-infected varieties of fescue or other grasses. There are endophyte-free as well as novel-endophyte varieties of tall fescue that can be used to replace the endophyte infested stand. The novel-endophyte varieties are infected with strains of fungus that provide some of the beneficial effects with few of the detrimental effects. 

Attempts to reduce the effects of the endophyte fungus through feed additives or treatments applied to the cattle have not consistently shown benefits. However, it is recommended that cattle grazing infected fescue not be additionally stressed by heavy parasite loads, mineral deficiencies, or other disease. The best approach to managing fescue so that the negative effects of the endophyte are minimized will depend on your local conditions. By working closely with area extension and agronomy specialists, you can develop a plan for coping with this problem.

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Although mastitis (infection of the udder) is often considered a dairy cow problem rather than a beef cow problem, the disease does affect many beef herds. Most cases of mastitis only involve one quarter (one teat) of a cow’s udder and the other three quarters remain normal. Even though most cases of mastitis do not result in the complete loss of milk production, calves from affected cows have lighter weaning weights than if their dam had a normal udder. Occasionally, mastitis causes severe illness in the cow, but in most situations, the cow is not greatly affected other than having reduced milk production. Mastitis can occur at any stage of lactation or even when the cow is dry, but most commonly becomes a problem early in lactation shortly after a cow calves.  

Most cases of mastitis are caused by germs that are very common in the environment and on a cow’s skin. Occasionally, mastitis is caused by injury to the udder.  Lactating cows are by far the most commonly affected, but heifers and even bulls or steers can have infected udders. Severe cases of mastitis, when the udder becomes reddened, swollen, and hot to the touch and the cow shows signs of illness such as being off-feed and inactive, will result in severe weight loss in the calf and cow and occasionally the death of either the cow or calf. Often, a beef producer or veterinarian will not notice a cow with mastitis because beef cattle are not typically observed daily from a short distance and many cases do not result in visible swelling or other signs of udder infection. In situations when cases of mastitis are not detected, the cow is likely to remain infected throughout the lactation and possibly for the rest of her life.  

If mastitis is diagnosed, cows can be treated with special formulations of antibiotics that can be infused into the udder itself through the end of the teat. The veterinarian may also choose to treat cows with mastitis with antibiotics injected under the skin of the neck that then travel through the blood stream to the udder. Many cases of mastitis respond well to treatment, but some quarters never return to full milk production. If a cow with mastitis is severely ill, the veterinarian may recommend aggressive therapy with frequent milking out of the affected quarter, the use of anti-inflammatory drugs, and antibiotic therapy.  

Because beef cows are not handled frequently, the most common time to check cows for mastitis is when they are gathered for purposes of vaccination, fly control, or breeding early in lactation, or at the end of lactation when the cows are checked for pregnancy status and/or the calves are weaned. Some herds routinely check udders and treat any affected cows at the time the calves are weaned.  

Although it is probably not possible to prevent all cases of mastitis, heavy fly populations, calving in a drylot, and poor teat and udder confirmation are linked with situations with multiple cows being affected in the same herd. Older cows, particularly those with larger, low-slung udders and large teats are considered to be at greater risk for mastitis. Therefore, prevention focuses on calving cows on clean pasture and avoiding calving in wet or muddy environments, culling potential replacement heifers if their dam has poor udder or teat confirmation, and controlling flies by focusing on sanitation and appropriate use of insecticides.  

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Cattle are an amazing animal species for many reasons. One of the most important reasons is because they can thrive when fed a wide variety of diets and feedstuffs. Because of the rumen, cattle are able to utilize forages that are not appropriate for simple-stomach animals; in addition, cattle can eat grains, by-products of grain processing, and waste from human food production. However, it is important to know that if diets are changed without an adaptation period or if cattle have sudden access to a new feedstuff, health problems can follow.  

Changing form one roughage source to another or from a high-grain, concentrate diet to a roughage diet is usually well-tolerated; in contrast, suddenly changing from a roughage diet to a concentrate diet can be accompanied by acidosis, a serious digestive problem in grain-fed animals. In cow-calf operations, cattle are rarely intentionally fed a diet consisting primarily of grains, but sometimes growing bulls or heifers are fed a high-grain diet, and cows may have the opportunity to consume more gain than the producer intends when grain is used to supplement low-quality, dormant forage.  

Acidosis can occur following a large meal of feed rich in readily fermentable carbohydrates that causes the rate of lactic acid production in the rumen to exceed how quickly it can be used. Cereal grains such as wheat, barley, corn, sorghum (and to a lesser extent oats) as well as high sugar or starch content fruit or root crops (apples, potatoes, sugar beets etc.) are associated with acidosis. Green, unripe corn, corn or milo stubble fields, and byproduct feeds such as bakery waste, elevator fines, and some brewer’s grains are also high in starch or simple sugars making cattle eating these feeds also at risk for acidosis. Feeds that are not likely to induce acidosis are hay and fiber-type byproduct feeds. Hay does not contribute to acidosis because the energy source is mostly cellulose rather than simple sugars and the physical properties (large particle size) resist rapid fermentation. Fiber-type byproduct feeds such as soy hulls, distillers grains, or corn gluten feed are similar to hay in that the energy source is primarily cellulose with little starch or simple sugar present. Fine grinding of grain, rapid changes in the amount of grain or other high-starch feeds in the diet, or cattle that become hungry and then eat a large meal of grain are often implicated in the disease.  

Cattle that are suffering from acidosis can look a lot like cattle with respiratory disease by showing a lack of appetite, slow movement, increased heart rate and breathing rate, and elevated body temperature. In mild cases of acidosis, cattle will appear to have a full rumen, they may act uncomfortable due to a sore belly, and will probably have grey-green pasty to soupy diarrhea. In more severe cases, dehydration is severe, the animal will usually be laying down, the abdomen is markedly distended, and the animal is noticeably uncomfortable (groaning and grinding of teeth). Diarrhea is profuse and yellow-green and then progresses to watery, often foamy with a pungent odor. Death commonly follows severe cases. Cattle that recover from acidosis may develop liver abscesses, laminitis, or other secondary diseases.  

Mild cases of acidosis are commonly treated by removing the feed causing the problem and possibly administering a buffer by stomach tube. Treatment of more serious cases may include siphoning off ruminal contents with a stomach tube or surgically opening the rumen and removing the rumen contents followed by re-inoculation of fresh rumen contents from a healthy animal. In addition, large volumes of intravenous (IV) fluids are given. In this disease process, IV fluids must be used because fluids given by mouth (via stomach tube) will not be absorbed from the rumen into the rest of the body.  

Acidosis is prevented through feeding management that avoids a sudden increase in intake of grain or other readily fermentable feeds, sufficient bunk space so that aggressive eaters don’t have access to feed amounts intended for several animals, and good bunk management so that cattle are not overly hungry. In addition, inclusion of an ionophore in the ration helps to decrease the incidence and severity of acidosis. 

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

It is important for everyone involved in beef cattle production, including seedstock producers, cow-calf producers, backgrounders and stocker operators, feedlot managers, packers, retailers, feed suppliers, and veterinarians to remember that all the money distributed among the many participants is generated by the sale of beef to consumers. While it is true that carcass traits and beef product attributes are largely influenced by the genetic decisions of seedstock and commercial cow-calf producers and the feeding decisions of feedlot managers and nutritionists, the animal health decisions made by producers and veterinarians throughout the production chain also play a role. A number of studies have indicated that muscling, marbling, and tenderness all can be negatively impacted by cattle health problems.  

Studies of consumer preferences have indicated that attributes such as flavor, tenderness, marbling, and texture are important when evaluating the eating experience when consuming beef cuts. These consumer expectations are important when considering the impact of animal health because pneumonia and other common cattle diseases have the potential to affect not only carcass weight, but also the amount, location, and ratio of muscle, fat, and water.  

Bovine respiratory disease (pneumonia) is the most important cause of illness and death in feedlot cattle with digestive diseases such as acidosis and bloat also being important. Several studies have shown that cattle that experienced respiratory disease had lighter hot carcass weight, lower dressing percent, less internal fat, and lower marbling scores as well as less external fat and smaller ribeye area than cattle without respiratory disease. Scientists don’t have a clear picture of how disease impacts carcass traits, but probably a combination of changes in hormones such as insulin, growth hormone, and other signals that direct the growth of muscle and the deposition of fat are involved.  In addition, just the fact that cattle are off-feed while they are sick may impact the pattern of muscle growth and fat deposition.  

The negative effects of disease on carcass traits may not be confined to the time cattle are in a feed yard. As we learn more about muscle growth and fat deposition, it appears that stress, disease, or poor nutrition even early in life can have consequences on feedlot and carcass performance. This understanding makes a life-long health and nutrition plan to minimize disease risk and ensure optimum growth from birth to slaughter important for efficient production of a desirable beef product. Beef producers should work with veterinarians to optimize sanitation, nutrition, immunization, and biosecurity to reduce the risk of disease. In addition, because the negative effects on growth and carcass traits appear to be more severe in animals with prolonged or multiple episodes of sickness compared to animals that become sick for a short period of time and then recover, knowledge and ability to accurately identify sick animals and to treat them in a timely manner also becomes increasingly important.  

Life-long cattle health starts with the cow being in good body condition and receiving all necessary nutrients throughout pregnancy and then giving birth without calving difficultly in a clean environment. If the calf is born healthy and able to quickly stand and suckle and that calf is not exposed to mud and manure, it is likely to avoid the risk of scours and pneumonia during the time period from birth to weaning. Adequate forage availability for both the cow and calf until weaning is essential to maintain optimum health and to ensure that the calf has good post-weaning growth and health.  

Effective vaccines are available for a number of important disease-causing germs including the bacteria that cause blackleg and related diseases, and the viruses and bacteria that contribute to bovine respiratory disease. Both internal parasites (worms) and external parasites (flies, ticks, and lice) can cause significant disease in calves; and proper use and timing of deworming and external parasite treatments greatly aids in cattle health and well-being. The time period around weaning is a period of high risk for respiratory disease and other diseases. Implementation of well-designed preconditioning programs that utilize low-stress weaning, vaccinations, parasite control, and acclimation to post-weaning diets and feeding and watering equipment is an excellent disease control strategy.  

Carcass premiums and pricing on carcass merit grids has caused the veterinary profession to re-evaluate the cost of cattle diseases. Historically, veterinarians and beef producers have considered the cost of disease to be confined to death loss, treatment cost, decreased feed efficiency, and reduced live weight. However, because many cattle are now sold on a carcass merit basis, disease has the potential to affect profitability not only through treatment costs, death loss, and reduced weight, but also the amount, location, and ratio of muscle, fat, and water and the ultimate desirability of the final beef product.   

Ensuring that consumers have a satisfying experience every time they eat beef requires that all the participants in the beef production chain do their part to improve and protect the attributes of flavor, tenderness, marbling, and texture. In addition to the significant impacts that genetics and nutrition play on carcass and product traits, cattle health also has an important role; and a plan to optimize health from birth to slaughter is an important component of providing a high-quality beef product.  

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

Both beef producers and veterinarians express frustration when a cow that is identified as pregnant later aborts the fetus during mid-pregnancy. Because reproduction is complex and a number of germs, toxins, and genetic problems can lead to pregnancy loss, veterinarians recognize that losing about 1% to 2% of pregnancies between the time of pregnancy diagnosis and calving is probably unavoidable. The goal of many aspects of cowherd health programs including nutritional management, biosecurity, and vaccination is to reduce the risk of abortion and particularly to prevent situations when more than 5% of the herd aborts.  

Veterinarians approach abortion management by focusing on two related activities: diagnosing the causes of abortion and preventing abortions from occurring. Cowherd abortions can occur either sporadically or in larger outbreaks. Sporadic abortion losses are considered to occur when less than 2% of the entire herd aborts and no group of cows as described by age, pasture, or other risk-group has greater losses than other groups. When investigating sporadic abortion losses, it may not be justified to spend a great deal of resources to attempt to identify the causes; but if a larger abortion outbreak is occurring, a thorough investigation to discover the factors that are contributing to the losses is necessary to identify changes in herd management to prevent similar outbreaks in future years. The problem that both cattle producers and veterinarians face when a few cows abort is to determine if an abortion storm is beginning or if the few identified abortions are the only ones the herd will experience.   

When the first abortion is identified by finding an aborted fetus or seeing signs of abortion in a cow previously diagnosed as pregnant (such as a retained placenta or return to heat) the veterinarian may want to collect samples from the fetus, the cow, and the placenta and to record information about the aborting cow such as her age, the date the abortion was discovered, the estimated fetal age, and the identification of the pastures she has been located during pregnancy. The samples may be sent to a diagnostic laboratory or the veterinarian may suggest that the samples be saved and only submitted for laboratory investigation if more abortions occur. Some causes of abortion are fairly easily identified by a diagnostic laboratory if the samples are fresh, but other abortion-causing germs and toxins are difficult to confirm. Many of the causes of abortion work fairly slowly, so that there are many days or weeks between the time that a cow is exposed to the cause of the abortion and the actual loss of the fetus. In these situations, the diagnostic laboratory may not be able to identify an abortion cause that is no longer present in the fetus or the cow. In other situations, the germs or toxins that cause abortion affect the cow but may not actually invade the fetus making samples taken from the fetus of no help for making a diagnosis. It is important to realize that even in situations in which the diagnostic laboratory does not identify a cause for the abortion, important information is gained by removing certain easily-diagnosed factors from the list of likely causes.  

Veterinarians and cattle producers work together to create management plans that help to prevent abortions by targeting the most likely causes that can be effectively controlled. Biosecurity plans that rely on diagnostic testing and herd segregation to minimize the risk and effect of trichomoniasis (Trich) and Bovine Viral Diarrhea (BVD) should be created to meet each herd’s specific level of risk. Online tools named Trich CONSULT (https://ksubci.org/trich-consult/) and BVD CONSULT (https://ksubci.org/bvdbovine-viral-diarrhea-control-consult/) are useful to create herd-specific biosecurity plans for these diseases. Vaccination protocols to increase herd immunity against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), leptospirosis, and campylobacteriosis (vibriosis) should be implemented with an emphasis on building immunity in herd replacements as well as maintaining immunity in mature adults.  Other diseases such as neosporosis, foothills abortion, and pine needle abortion are difficult or impossible to control with diagnostic testing, herd segregation, or vaccination. Some abortion risks must be addressed by having good feed security while other require carefully planning the best age and stage of pregnancy to expose cattle to pastures where abortions are likely to be initiated when the cause of abortion is either plants or diseases carried by ticks or other insects. Effective control measures have not been identified for some causes of abortion, and the best management in these situations is to work toward good overall herd health and to keep the accumulated level of abortion risk low.  

While it is impossible to prevent all abortions, a well-planned strategy designed by a veterinarian and cattle producer working together to target the most important risks for each specific herd provides reasonable protection against devastating pregnancy losses. The best herd health plan to prevent abortion losses is the plan that optimizes nutrition, biosecurity, vaccination protocols, and grazing management for your herd. 

Bob Larson, DVM, PhD Reproductive physiologist and Epidemiologist Beef Cattle Institute Kansas State University RLarson@vet.k-state.edu

For most of the U.S. and Canada, winter feed is one of the greatest costs of cow-calf production. The base ingredient in winter rations is usually standing dormant forage or hay. Heifers, fist-calf heifers, and thin cows that need to gain body condition often need more energy than can be supplied by dormant forage or hay alone. Therefore, many situations require that heifers and cows be fed supplemental protein, energy, or both, depending on the nutrient makeup of the base-forage. Understanding the interaction between starch, fiber, and protein in the cows’ rumen allows producers to determine the most appropriate winter supplement. 

Many different types of bacteria and other microorganisms in the rumen convert forage and supplements into nutrients needed to maintain or increase a cow’s body weight. What makes cattle and other ruminant animals so important to the earth’s ecosystem is that a great deal of the energy stored on the planet is stored in the fibrous parts of plants that cannot be used by non-ruminants (humans, birds, and most animals). In addition, it is important to recognize that even cattle and other ruminants can only use the energy stored in the cell walls of plants when the rumen bacteria have enough protein and other nutrients to actively breakdown the fibrous plant parts. Fiber-digesting bacteria, which are important for digesting forage, are relatively slow growing and are easily killed if the rumen becomes acidic. In contrast, starch-digesting bacteria are important to grain-fed ruminants, and reproduce rapidly when starch is available. Starch-digesting bacteria have a much greater tolerance for increased acid in the rumen than do fiber-digesting bacteria. 

Changes in diet will change which types of bacteria in the rumen are most plentiful. The types of supplements that cattlemen choose to feed will affect the types of bacteria that dominate the rumen which will have an effect on how well cows can convert the base forage into body weight. Some supplements will increase the digestibility of the base forage, some will not greatly affect the base forage digestibility, and some will actually decrease the ability of cows to convert forage into body weight.  

Cattle fed a forage-based diet (grazing or hay) that is deficient in protein (<7% Crude Protein) will benefit by being fed a protein-dense supplement to supply the necessary amount required for reproduction by fiber-digesting bacteria. By increasing the number of fiber-digesting bacteria in the rumen, forage digestibility is increased, the cows’ eat more forage, and the energy yield from the diet is improved.  

However, producers should realize that if the base forage has adequate protein content, additional protein will not improve digestibility or energy yield. A typical 1,200-pound cow of average producing ability will need only about 1.7 pounds of crude protein during the middle part of gestation. Feeding a roughage of fair quality (8 to 10% crude protein) during this period should meet both energy and protein requirements, and feeding a protein supplement is not necessary. In contrast, after a cow calves, her requirement for protein increases greatly. A 1,200-pound cow producing 20 pounds of milk requires 3 pounds of crude protein daily and a forage that was adequate in mid-gestation may be very protein deficient for late gestation and early lactation. 

Because of the competition that takes place in the rumen between starch-digesting and fiber-digesting bacteria, it is important to limit the amount of grain in the diet of cows grazing standing dormant forage or eating hay. If cows are eating forage of moderate quality (protein content and digestibility), supplementing with too much grain, which is high in starch, will actually decrease the digestibility and available energy from the forage even further. This decrease is due to a shift in the population of rumen bacteria away from a population dominated by fiber-digesters, to a population dominated by starch-digesters. Remember, the starch-digesting bacteria can reproduce rapidly when starch is available, and during rapid growth, starch-digesting bacteria produce increasing levels of lactic acid, which will kill many fiber-digesting bacteria. With fewer fiber-digesting bacteria available, forage digestibility is decreased and energy yield from the forage is reduced.  

Because corn and other grains are readily available and often are price-competitive with other sources of energy, producers can use these feeds up to the level where they have a negative effect on fiber digestion. The cut-off for starch supplementation of low-quality forages calculates to be about 0.28% of the cows’ bodyweight for corn dry matter (3.5-4.0 lbs. of corn as-fed for a 1,200-pound cow). For moderate weight gain, a simple diet of forage and less than 3.5-4.0 pounds corn will often be sufficient.  

In situations when the base forage has adequate protein, if more weight gain is required than can be met with a starch-based feed such as corn without a negative effect on forage intake and digestibility, producers can choose to use a fiber-based feed that has higher energy content than the base forage. Many by-product feeds provide energy in the form of highly digestible fiber; because the energy is in the same form as that in the forage, high levels can be fed without harming the fiber-digesting bacteria in the rumen or decreasing forage digestibility. By-product feeds that provide energy in the form of highly digestible fiber include: corn gluten feed, distillers grains, soybean hulls, and wheat middlings.  

Working with your veterinarian, nutritionist, Extension specialist, or other ration-planning resource to help you properly select the type and amount of supplement that compliments your base forage will ensure that your cows maintain adequate body condition and that winter feeding bills are optimized.