Most areas of Oklahoma have had adequate summer forage to allow pregnant replacement heifers to be in excellent body condition going into late fall and winter. Now producers are faced with the challenge of maintaining body condition on the replacement heifers through the calving season and into next spring. As the title of this article suggests: “Body condition score at calving is the key to success.” Body condition (or amount of fatness) is evaluated by a scoring system that ranges from 1 (severely emaciated) to 9 (very obese) Examples of heifers too thin (BCS = 3) and good condition (BCS = 6) are pictured below.
Research data sets have shown conclusively that young cows that calve in thin body condition but regain weight and condition going into the breeding season do NOT rebreed at the same rate as those that calve in good condition and maintain that condition into the breeding season. The following table from Missouri researchers illustrates the number of days between calving to the return to heat cycles depending on body condition at calving and body condition change after calving.
Predicted number of days (d) from calving to first heat as affected by body condition score at calving and body condition score change after calving in young beef cows. (Body condition score scale: 1 = emaciated; 9 = obese) Source: Lalman, et al. 1997
Notice that none of the averages for cows that calved in thin body condition were recycling in time to maintain a 12 month calving interval. Cows must be rebred by 85 days after calving to calve again at the same time next year. This data clearly points out that young cows that calve in thin body condition (BCS=3 or 4) cannot gain enough body condition after calving to achieve the same rebreeding performance as two-year old cows that calve in moderate body condition (BCS = 5.5) and maintain or lose only a slight amount of condition. The moral of the story is: “Young cows must be in good (BCS = 5.5 or better) body condition at calving time to achieve acceptable rebreeding performance.” Make certain that the supplement program is adequate for your young cows to be in good body condition this spring.