Maximize Forage Resources Now To Maintain And Improve Body Condition Scores In Your Cow Herd

By Dr. Glenn Selk

Dr. Glenn Selk, Oklahoma State University Emeritus Extension Animal Scientist, offers herd health advice as part of the weekly series known as the "Cow Calf Corner" published electronically by Dr. Peel and Dr. Glenn Selk. Today, Dr. Selk attempts to help producers try to maintain and improve body condition in their cow herd for safe, healthy calving this spring.

"Cows in some Midwestern herds are calving (or already have calved) in marginal body condition. Unfortunately, this is a season where maintaining or gaining body condition on spring calving cows is really quite difficult. Warm season grasses have not yet begun to grow. Dormant grass (what little is left) is a low quality feed. Cows cannot, or will not, consume a large amount of standing dormant grass at this time year. If the only supplement being fed is a self-fed, self-limited protein source, the cows may become very deficient in energy. Remember, the instructions that accompany these self-fed supplements. They are to be fed along with free choice access to adequate quality forages.

"There is another factor that compounds the problem. A small amount of winter annual grasses may begin to grow in native pastures. These are the first tastes of green grass many cows have seen since last summer. The cows may try to forage these high moisture, low energy density grasses, in lieu of more energy dense hays or cubes. The sad result is the loss of body condition in early lactation beef cows just before the breeding season is about to begin.

"Body condition at the time of calving is the most important factor affecting rebreeding performance of normally managed beef cows. Nonetheless, condition changes after calving will have more subtle effects on rebreeding especially in cows that are in marginal body condition. Body condition changes from the time the cow calves until she begins the breeding season can play a significant role in the rebreeding success story. This appears to be most important to those cows that calve in the marginal body condition score range of '4' or '5.'

"An Oklahoma State University trial illustrates the vulnerability of cows that calve in the body condition score of 5. Two groups of cows began the winter feeding period in similar body condition and calved in very similar body condition.

"However, after calving and before the breeding season began, one group was allowed to lose almost one full condition score.

"The other group of cows was fed adequately to maintain the body condition that they had prior to calving. The difference in rebreeding rate was dramatic (73% vs 94%). (Wettemann, et al., 1987 Journ. Animal Sci., Suppl. 1:63). Again this illustrates that cows that calve in the body condition score of 5 are very vulnerable to weather and suckling intensity stresses and ranchers must use good nutritional strategies after calving to avoid disastrous rebreeding performance.