Body condition at calving is the most critical factor in determining reproductive performance. High pregnancy rates will not occur in first-calf heifers unless they are able to gain some fat cover during the breeding period. This can be difficult to do For young stock with calves at side. Thin cows need to increase body condition, and moderate condition cows need to maintain body condition. Correcting deficiencies prior to calving is easier and cheaper.
BCS 4 If a cow is BCS 4 or thinner, she will be slow to return to heat and may not rebreed on time. Feeding a high level of nutrition after calving can sometimes shorten the postpartum interval from calving to first heat in thin cows (BCS 3-4), but the postpartum interval will usually be longer than if the cows had calved in good condition (BCS 6-7). Therefore, early weaning the calf at 50 days of age or at the start of the breeding season may have to be considered. Manage these cows with those in the BCS 6 group. The calves can be raised on self-feeders using an early weaning ration. The cows, even if quite thin, should return to estrus within three weeks after weaning and will thus rebreed to have a calf next year. It is far easier and cheaper to make cows gain weight before calving than after calving when the added requirement of lactation is present. A parasite evaluation is certainly merited.
BCS 5 If a cow is a BCS 5, continue to Feed hay or grain and protein supplement to be sure that she does not lose condition before the breeding season. Many cows calve at condition scores less than 5 and still have excellent rebreeding rates when weather and nutrition conditions do not cause extraordinary stress during this critical period (two months before calving through the breeding season). A borderline 4-5 BCS cow that is exposed to severe environmental stress may require the calf to be removed for 48 hours, 10 days before the breeding season. This should help a stressed BCS 5 cow to return to heat and rebreed on schedule. This program will probably not work with very thin cows. The calves should be offered palatable feed and plenty of water while they are separated from their dams.
BCS 6 If she is a BCS 6 (or even fatter), continue with normal management and feeding. While good body condition at calving time is an indication that rebreeding should proceed without difficulty, good condition at calving does not guarantee acceptable rebreeding performance. Cows losing condition after calving have lower conception rates than do cows maintaining condition.