I believe every extension agent in history has emphasized the importance of body condition score (BCS) in cow herd management, so it may not be surprising to see this title in my column. However, drought has ravished many parts of the country. Knowing limited forage availability often results in lower cow BCS, it is important to point out a few main reasons to have cows in a BCS of 5 or 6 prior to calving.
- Fetal programming – Research has shown that maternal nutrition can impact fetal growth and development while influencing the performance of unborn offspring. Nutrient restrictions during pregnancy, especially in thin cows, can lead to poorer post-weaning performance and lower subsequent reproductive rates of offspring. The word limit on this column won’t accommodate a literature review on fetal programming, but know that extensive research in this area is worth considering when making management decisions for thin cows.
- Colostrum – A more commonly discussed implication of cow BCS is the impact on colostrum quality. Research has shown that calves born to cows in better BCS have better calf serum immunoglobulin levels when compared to thin cows. Immunoglobulins are the important proteins in “mother’s first milk” that contain antibodies. Higher levels of immunoglobulins provide greater protection from pathogens for calves.
- Calving assistance – Cows in good BCS are best fit to handle calving. Thin cows and cows that are nutrient-restricted have been shown to have increased calving difficulty. To also confound things, calves being born to thin cows tend to be weaker and less vigorous at birth. Overconditioned cows that are too fat can also exhibit calving difficulty, as deposited fat stores in the birth canal can result in more dystocia.
- Subsequent reproduction – Ultimately, getting a cow to calve successfully and raise a productive calf is not enough. She has to do it – and do it every year. Quick breed-back is a key component to a sustainable, profitable cow herd. Cows in good BCS have lower postpartum intervals and thus stay at the front of your calving season. The snowball effect of keeping cows calving at the front of your season is huge. Daughters of cows calving in the first 21 days of your calving season are more likely to breed-up at higher percentages and follow the path of their early calving mothers.
Drought and limited forage availability can result in thin cows. Be mindful that management decisions to achieve appropriate BCS prior to calving are a worthwhile effort that can have immediate and lasting impacts on the performance and profitability of your cow herd.
