With spring-calving herds, we spend a lot of time each fall writing down numbers… animal ID, waning weights, pregnancy, calf age. Unfortunately, it often all seems to wind up in a notebook in the barn or on the office computer, never to be seen again. However, if we evaluate these numbers annually they can help us make better management decisions.
For instance, we can compare them to industry benchmarks to evaluate such things as the reproductive performance of the heard.
When we benchmark, we compare the performance of a specific herd against accepted targets. In most cases, these targets are production output numbers, such as percent pregnant or pounds weaned. These measures must be defined in a standardized way across all herds. This is done so that we truly get an “apples-to-apples” comparison.
Four important benchmarks to evaluate reproductive efficiency are:
Overall pregnancy rate:
Calculated as the number pregnant divided by the total number of females exposed for breeding, multiplied by 100. Depending on herd size, location and length of breeding season, we would expect > 90 percent of females to become pregnant in a limited breeding season (60-90 days).
Percent pregnant in first 21 days of breeding:
Calculated as the number of females pregnant in the first 21 days of the breeding season divided by the total number of females exposed for breeding, multiplied by 100. At least 60 percent of the total number of herd pregnancies should fall into this time frame. To calculate this number, you must age the fetus (via palpation or ultrasound) and record the date the breeding season started and ended.
Pounds weaned per exposed female:
Perhaps the most useful benchmark of all because it can be affected by reproductive efficiency, calf growth rate and the overall animal health program. Add up the total number of pounds weaned and divide by the number of females exposed to produce those calves. A reasonable starting target would be 475-525 lbs. However, this benchmark varies widely due to environmental conditions and herd genetics, so it is critical to track it annually in your individual operation.
Late-term abortion rate:
After pregnancy checking your cows, you won’t be able to calculate this benchmark until the end of 2012 calving season. To calculate this number, compare the number of cows expected to calve with the number that actually do product a full-term calve (live or dead). Obviously, cull cows are not included. This benchmark should not exceed 3 percent. For example, if you expect 100 cows in your operation to calve, at least 97 of these cows should deliver a full-term calf.
Obviously this is not a complete list of benchmarks; others deal with calf performance and input costs. However, using just these four provides a starting point that may have a profound effect on your herd’s profit potential. Operations that fail to meet these targets tend to have issues in at least one of the three areas: grass management, supplemental feeding or animal health. so as you’re collecting those numbers this fall, take the time to actually use the data to evaluate your herd’s performance. That’s where the decision-making process should begin.
Terry J. Engelken, D.V.M, M.S, Associate Professor, Veterinary Diagnostics and Production Animal Medicine, Iowa State University.