A cow's reproductive performance is measured by her ability to conceive, deliver and "mother" a calf to weaning every 365 days. In a commercial cow-calf operation, this is the primary factor affecting profitability. Most instances of poor reproductive performance in a herd are due to inadequate nutrition. Body condition score (BCS) is a proven tool to determine nutritional status of an animal. The Beef Improvement Federation emphasizes that, "Current body condition influences subsequent growth, reproduction, milk production and life span." These are all critical economic traits. In spring-calving herds, weaning is an ideal time to evaluate the herd's BCS and, if needed, adjust winter nutrition to ensure cows will be in at least a BCS of 5.5 at calving next spring. How important is this? Look at the table.
To continue on a 365-day calving interval, cows must rebreed within 80 to 85 days of calving. Trial 1 shows cows calving in BCS 4 aren't even cycling 80 days post-calving. Further, Trial 2 shows they won't rebreed in acceptable numbers unless and until they add condition up to a BCS 5, regardless of how long you leave the bulls out (six months in this trial). There are many other trials like these with similar findings.
Descriptions of the nine gradations of BCS are fairly universal and can be easily found in print and online. The cow in the photo is obviously empty, but she is in a BCS of 5.5. She has a smooth appearance because all her ribs are completely covered. Her topline is smooth, and there is some fat deposition around her tail head and behind her shoulder.
In a BCS 4, her topline would still be smooth, but her last two ribs would be visible at all times. There would be little to no indication of fat around her tail head or behind her shoulder. In a BCS 6, she'd have more fat in those areas with noticeable deposition in her brisket and more smoothness over her rump.
After weaning, spring-calving cows are at their lowest level of nutritional requirement for the year. If body condition needs to be added, this is the most efficient time to do it. Score your herd now, and provide nutrition to maintain or achieve a BCS 5.5 by calving time.