We’ve turned over the calendar year, and many beef producers in the Northwest are well into winter feeding as well as preparing for calving season. Nutrition at this time is dual-focus – for the health of the cow and for the health status of the calf fetus.
Beef cows should have an adequate body condition score (BCS) pre-calving, which would be 6.5 to 7 for heifers and 5 to 6 for mature cows. BCS is related to many critical aspects of production such as conception rate, days to estrus, calving interval and colostrum, and milk production. Thin cows at calving may not fully recover by breeding and will be reproductively inefficient and more susceptible to additional health problems.
This is a critical period of the production year – what is done for the fetus at this time impacts its survivability and long-term health and performance, and what we do at this time for the cow affects her future breeding performance. In the final trimester of gestation, energy and protein needs will increase by 20% dry matter (DM), as will vitamin and mineral requirements. Protein requirements can be met by grass and alfalfa hay, but it’s important to test your hay for protein so you know whether you need to supplement or not. Typical-sized mature cows will be eating 19 to 28 pounds depending on weight; a minimum of 7.9% of that should be protein with a higher amount for maximum productivity. For first-calf heifers, depending on potential mature weight, they’ll be consuming 16 to 24 pounds with at least 8.2% needing to be protein.
About two-thirds of fetal growth occurs during the last trimester. The cow is programmed to take care of the fetus at the expense of her own body, and losses of condition can occur in late pregnancy when daily protein and energy are not increased to meet the needs of pregnancy. Additionally, if energy is inadequate during the last trimester, it can lead to poor rebreeding. If you need to supplement any nutrient, realize response time is a key factor. It must be fed for an adequate period prior to a production phase and continued through the entire phase.
Once the calf is on the ground, in addition to lactation, the cow will be recovering from parturition, and cows in moderate condition at calving should at least maintain bodyweight from calving to rebreeding for good conception rates; a failure to take into account the increased protein and energy demand brought on by lactation may result in a long interval before rebreeding. In the next article, colostrum production and management as it relates to nutrition will be the focus. Happy New Year.
Read part two of this series, “West: Nutrition at calving, part 2.”
