Boosting bull returns

摘要

There's nothing glamorous or new age about auditing the fertility of bulls, but it's still one of the simplest and cheapest ways cow/calf producers can hedge their bets on bull investment. After all, Glenn Coulter of the Lethbridge Research Center for Agriculture Canada at Lethbridge, Alberta, points out, "In an unselected population (of bulls), we say 20-40 percent of them are deficient reproductively. They aren't sterile, but they will have fewer calves than you want them to." That means you mayget calves on the ground, but you may not get as many sired by the bulls you invested more heavily in. "An individual has to look at their objectives, where they want to go, how they want to get there and how much risk they can comfortably live with to accomplish their goals," Coulter says. "Getting cows pregnant is one thing; making significant genetic improvement is another thing." As an example, assume a bull whose genetic merit you are relying on ends up being 20 percent less fertile (defined here as number of conceptions/cow exposed) than a sire of equal merit that you could have used on a particular group of cows. Now figure an 85 percent calf crop/cow exposed - 25 cows/bull.