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BCI Cattle Chat – Episode 11

Topics

1:43 – Questions about Trade

9:08 – Fair Season and Value of 4-H/FFA

11:45 – Lameness in Calves

14:47 – Implanting Calves

For more on BCI Cattle Chat, follow us on Twitter @The_BCI, and check out our new website, ksubci.org. If you have any comments/questions/topic ideas, please send them to bci@ksu.edu.

Hosted By: Dr. Brad White, Dr. Bob Larson, Dr. Bob Weaber and Dr. Dustin Pendell

 

Vet Call: Nutritional aspects of cattle health

By Dr. Bob Larson, DVM
Reprinted with permission from the Angus Journal.

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, energy and protein needs of cattle with relatively low nutritional demands, such as mature cows that are not lactating and bulls that are not active. 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 drives 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 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 can also cause potential negative effects. 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 a 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 include 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 herd 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.

Dr. Larson is a professor of production medicine with the College of Veterinary Medicine at Kansas State University, Edgar E. and Elizabeth Coleman Chair of Food Animal Production Medicine, executive director of Veterinary Medical Continuing Education, and faculty member with the Beef Cattle Institute. He specializes in the integration of animal health, production efficiency and economic considerations in beef cattle production. This column is reprinted and redistributed with permission from the Angus Journal.

Research Update: Duration of postpartum anestrus in cows and heifers

The length of time it takes for a cow to resume fertile cycles after calving directly affects the reproductive performance and efficiency of a cow-calf herd. Dr. Robert Larson, professor of production medicine, collaborated with Dr. Doug Shane, Dr. Mike Sanderson, Dr. Matt Miesner and Dr. Brad White to develop a model investigating the effects on herds with differing lengths of time to resume fertility after calving over the course of 10 years.

Ideally, the average cow in a herd takes 50-60 days to resume cycling following calving when the cows are in good body condition. However, herds with a high percentage of thin cows, cows that experienced calving difficulty, or cows that are slower to resume fertile cycles after calving due to presumed genetic reasons may average slightly to much longer length of post-calving infertility.

“Relatively small increases in the length of post-calving infertility have detrimental effects on the herd’s productivity and those effects can persist for several years,” Dr. Larson explained. “Conversely, relatively small improvements also have important benefits.”

While the differences between a herd with optimal reproductive efficiency and less efficient herds can be difficult, if not impossible to see outwardly, the model provides quantitative evidence of change.

Calving heifers ahead of cows
In a separate study, the group developed a 10-year model determining the effects of breeding heifers before mature cows. One of the challenges when managing the length of post-calving infertility is to ensure that the youngest group of cows that just had their first calf are ready to breed by the start of the breeding season. These young cows tend to take longer to return to fertility than mature cows and good reproductive management of this important age-group starts long before they are bred for their first pregnancy.

“Focusing on development of replacement heifers is critical for good overall herd reproductive efficiency,” Dr. Larson said. “If replacement heifers can be managed so that all those that are selected to enter the herd will calve before the start of the mature cow calving season, all (or nearly all) of this age-group will have time after calving to resume fertile cycles by the start of their second breeding season.”

While breeding replacement heifers earlier than the mature cows provides benefits, it also requires additional management and may be inconvenient. The second model investigated how to select the optimum length of time to breed heifers ahead of mature cows. While the optimum heifer lead time is different for different herds, in general, the greatest bang for your buck occurs when heifers are bred to calve three to four weeks ahead of mature cows. While breeding even earlier provides additional benefits, the amount of improvement in reproductive efficiency decreases with each week earlier that heifer breeding is moved.

Read the published abstracts, papers and key points below.

Journal of Animal Science, Volume 95, Issue 4, April 2017: A deterministic, dynamic systems model of cow-calf production: The effects of the duration of postpartum anestrus on production parameters over a 10-year horizon
Key study findings

Journal of Animal Science, Volume 95, Issue 10, Oct. 2017: A deterministic, dynamic systems model of cow–calf production: The effects of breeding replacement heifers before mature cows over a 10-year horizon
Key study findings

Theriogenology, Volume 105, January 2018: Determining potential pregnancy status differences based on a new method of yearling heifer prebreeding examination
Key study findings