Bull Management before the Breeding Season
Parker Henley, Oklahoma State University Extension Livestock Specialist
A significant portion of reproductive failures in cow-calf enterprises are due to the fertility of the herd bull. With turnout just around the corner, it’s time to focus on your bull battery. Most spring calving cow-calf operations are 30-60 days from the start of the breeding season. There are two major considerations to keep in mind during this pre-turnout period: 1) have a veterinarian conduct a breeding soundness exam (BSE) on all potential herd sires, 2) monitor body condition score and slowly transition the newly purchased young bulls to a grazing setting.
Bull breeding soundness is one of the most economically important traits for cow-calf producers. Thus, a BSE is recommended to measure a bull’s potential to achieve satisfactory conception rates. The BSE should include examination of the reproductive anatomy, scrotal measurement, sperm motility, sperm morphology (physical characteristics), locomotion, eyesight and body condition score. A bull that passes the BSE appears to be sound for breeding purposes as best as science can determine at that point in time. Bulls should have a BSE 6-8 weeks prior to turn out. If a bull fails the BSE, this allows producers to have enough time to replace the animal with a sound bull for the breeding season.
Each year cow-calf operations purchase yearling bulls to replace sub-fertile bulls or poor genetics. Many seedstock producers develop bulls on grain-based, high energy diets prior to sale. Because bulls are typically managed to maximize gain and achieve physical characteristics appealing to buyers at a sale, they have the potential to be over-conditioned upon purchase. Bull buyers should consider gradually transitioning their newly purchased bulls to a lower energy, forage-based grazing system over the 30-60 days before they turn him out on cows. This period can allow the bull to shed excess fat and reach an optimum body condition for the breeding season. These bulls should be kept in a large enough pen or pasture so they can get daily exercise. When multiple bulls are used in a single pasture, they should be exposed to each other prior to turnout to minimize bull interactions once they join the cowherd. In conclusion, it’s never too early to plan for your next breeding season.
To view Dr. Johnson’s discussion on Maternal EPDs on Sunup TV Cow-Calf Corner from April 10, 2021:
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