By Sierra Kirchhoff
Special to Tiger Media Network
Bulls are a key piece in any cow/calf or beef operation. To make bulls worth their cost we usually think of a few general things; are they producing quality calves, do they get the job done (do they have the energy and stamina), do they have an adequate fertility rate, do they produce calves which fit the cows calving ability, and do they maintain a sound structure. Now, all of these key factors can be affected significantly by how we feed these bulls. From a nutrition standpoint, the argument can be made that a bull is only good as what it’s fed. Good nutrition and quality feed improve the longevity of a bull as a breeding animal. This ties back to the worth of a bull, as a bull that has longevity will stay in the herd for a longer period of time, producing more calves. Which spreads the initial investment of the bull out further and increases his profitability.
First, we will need to look at a common ratio for young bulls, which is often high-energy, to get the bull to its full potential in less time. When we think of feeding high-energy diets to our cattle we often tend to overlook the basics of nutrition. We get it set in our heads that more energy has just got to be the absolute best thing.
Secondly, we need to recognize that there are six main “nutritional” stages for bulls in a breeding program, that each differs in what nutritional needs a bull will have. These stages are pre-weaning, post-weaning, pre-puberty, conditioning prior to breeding season, maintenance/management during breeding season, and management after breeding season.
The pre-weaning stage is the developmental stage, where the calf will be relying on its mother to provide sufficient nutrients. In the case of the mother, or other environmental factors causing issues or limiting the desired nutrition for the calf, creep feeding can be used.
During the post-weaning stage, it is necessary for a bull to receive nutrients that will allow him to grow to his full potential, but this can also have a big effect on semen quality and sexual development. The idea behind feeding high-energy rations to post-weaning bulls is that it can decrease the time to reach puberty by growing the bulls rapidly. This is fine and dandy, however for particular breeds that reach puberty early, high energy can cause over conditioning.
Let’s talk about how these high-energy diets can affect our breeding stock, with a major focus on bulls. If we look solely based on the effect on scrotal circumference that high-energy diets provide we might be thinking that high energy is the way to go. However, post-weaning these diets only increase scrotal circumference by adding to the fat surrounding the area. This would be a similar phenomenon to how a cow could become over-conditioned in her brisket. Evidence shows that if bulls are fed high-energy after weaning there is rapid weight gain, however, high-energy can lend itself to excessive fat in the scrotum, reduction in semen quality and the increase in the chance for laminitis, fatty liver and rumenitis. This can also decrease spermatozoa mobility and mess with the morphology of the sperm itself.
In comparison, there have been many studies showing bulls who stay on a medium-energy ration from weaning to about two years had greater reserves of sperm cells and higher quality semen than bulls who were kept on high-energy in the same age frame. Keeping in mind that as a bull reaches breeding season he should be at a body condition score of 5.5 to 6.5 for quality performance.
In conclusion, we as producers should really pay attention to what we are feeding, in terms of what stage the bull is in, and what nutrients are required for correct and healthy performance. Bulls are truly an asset in a breeding program, and a good bull is not cheap, so we need to make sure we are not setting them up for failure with a lacking, or even overabundant nutrition program.
Sierra Kirchhoff, a 2017 Smith Center graduate, graduated this spring with a Bachelor of Science in animal science from Fort Hays State University. She is the daughter of Nate and Crista Kirchhoff, Smith Center.