Reproduction Performance (Butter-fat). By Gearld Fry, reprinted from Cowboy Wisdom, Jan 2012
Reproduction in our livestock herds is the highest sought after production trait and sadly the most misunderstood and misrepresented of all of them. Obtaining high reproductive performance is a genetic selection process and the role the bull plays is just as important as the role of the cow. The overwhelming majority is for a fact, trying to accomplish their reproduction goals using inferior bulls. James Drayson’s research presented later should help you to understand the different performance levels including the top level of breeder bulls.
A survey taken a few years ago revealed that only 70% of the cows in an average herd produce a live calf in a consistent12-month interval. The percentage is even lower in the south.
Many producers leave the bull with the cows all the time. In this scenario the cows conceive when their available energy reaches an adequate level that coincides with the quality of the bull’s semen. A cow may begin ovulating earlier in her lactation but because of the low quality (germ plasma) sperm of the so-called herd sire the sperm is not strong enough to fertilize the ovum and the cow remains open. As a result, so many ‘open’ cows are sold when there is really nothing wrong with them reproductively speaking. While the cow is viewed as the one not being able to conceive, it is more likely, from my experience, that the bull is not strong enough reproductively to get the job done even though a semen test done before breeding season indicated he should have been.
Open cows are always getting the blame when in fact they are only half of the reproduction equation. Bulls get the blame only when there is an obvious physical problem, but it’s the unseen (microscopic) that I want to address. A complete semen test takes a number of things into account to fully assess the breeding ability of the bull. When one or more of these different factors aren’t considered and evaluated there is no way of knowing there’s a lurking problem and thus the reason for most open cows. I’ll go into more detail in just a bit. Read More…