Improving problem recognition by basing dairy heard indices on reproductive status

摘要

Veterinarians use computer-generated indices as one method for recognizing change in the reproductive efficiency of a dairy' herd. We tend to react when index means fall outside expected norms for the farm or a management group. That strategy has fundamental problems. Unless essential reproductive data are monitored for completeness, inaccurate indices result. Because of the voluntary waiting period (VWP), time interval data distribute with a skew. Reaction to a mean may, therefore, be misleading. Indices based on, or heavily weighted by, the pregnant cow herd provide a historical perspective that, although important, may not relate to the current breeding herd situation. As a result, it remains difficult to recognize developing reproductive problems.