Part 3: Body Condition Scoring: Effects on Production
|Body Condition Score:||
Average time to first heat following calving (days):
|Table 1: Differences in postpartum interval for cattle at each body condition score (Houghton et al., 1990).|
Body condition of a beef cow at different times in the production cycle can have a profound impact on her production and profitability in the herd. Perhaps the most important impact that body condition can have on a cow’s performance is that of fertility and time to conception following calving. It is well recognized that as body condition decreases, the time to first heat (estrus) following calving increases. The average gestation length (pregnancy time) for a beef cow is 283 days. Knowing there are 365 days in one year leaves 82 days for the cow to breed back following calving in order to maintain a 1-year calving interval. Table 1 illustrates the average postpartum interval (interval from calving to first heat or after calving) for cattle at various body condition scores. Considering that the first heat cycle after calving is often sub-fertile, cows often conceive during the second heat cycle after calving. According to Table 1, the second heat cycle can be 91-110 days after calving in cows that are a BCS of 3-4/9. Cows in a BCS of 3/9 at the time of calving cannot actually be bred back in time to maintain a 365-day calving interval.
Depending on the time of year, the cost of feed needed to elevate a cow from a 3/9 or 4/9, to a 5/9 BCS may not be much compared to the cost of an extended calving interval or complete failure to conceive within the breeding season leading to premature culling from the herd. The body weight needed to change a cow’s body condition by one score varies depending on her frame size. Small to moderate frame cows require a 60-80 lb. increase in body weight, while larger frame size cows may require a 100-150 lb. increase in body weight.
The importance of body condition on fertility and pregnancy rates cannot be overstated. If cows are not at an appropriate body condition score, sub-optimal reproductive rate, decreased production and profitability, more calving difficulty, and weaker calves at birth.
- L. Houghton, R. P. Lemenager, L. A. Horstman, K. S. Hendrix, G. E. Moss, Effects of body composition, pre- and postpartum energy level and early weaning on reproductive performance of beef cows and preweaning calf gain, Journal of Animal Science, Volume 68, Issue 5, May 1990, Pages 1438–1446, https://doi.org/10.2527/1990.6851438x