Cow-Calf Certification Practice Exam

Which crossbreeding system yields the greatest advantage in pounds weaned per cow exposed?

1. 2-breed rotation

2. 2-breed composite

3. Terminal sire on purchased F1 females

4. Terminal sire on straightbred females

The correct answer is: Terminal sire on purchased F1 females

The option that yields the greatest advantage in pounds weaned per cow exposed is the use of a terminal sire on purchased F1 females. This approach harnesses the benefits of hybrid vigor, or heterosis, which typically leads to improved reproductive performance, growth rates, and overall health in the offspring. F1 females, resulting from a cross between two different breeds, can often outperform their straightbred counterparts in various traits due to the genetic diversity and vigor inherited from their mixed lineage. When these F1 females are mated with a terminal sire, the calves produced benefit from the sire's superior genetics, focusing on traits such as meat quality and growth rate, which in turn can enhance pounds weaned. This system is particularly effective because it takes advantage of both hybrid vigor from the F1 females and the high-performance traits associated with the terminal sire. The resulting offspring tend to be more productive, leading to a higher yield of pounds weaned per cow exposed compared to other crossbreeding systems such as 2-breed rotations or composite breeds, which may not capitalize on both hybrid vigor and specialized sire traits to the same extent.