Managing and Developing Young Beef Bulls
There are as many ways to feed and develop young beef bulls as there are seedstock producers. There are many and varied reasons that bulls are managed and fed the way they are. Whether bulls are developed on the ranch, in a commercial facility, or at a central bull test, they are usually fed to gain 2.8 to 4.0 pounds daily from weaning to one year of age.
One of the most common complaints from beef producers is the run-down condition of young bulls after their first breeding season. Most young bull will loss condition and weight during their first breeding season. However, minimizing the loss of body weight and condition will extend the bull's usefulness and productivity especially during their initial breeding season.
Can bulls be over-conditioned and/or under-conditioned before the first breeding season? The answer is probably yes. One might think an over-conditioned young bulls are better than under-conditioned bulls because if they are over-conditioned and they are expected to lose condition during the breeding season, at least they will still be in good condition at the end of the breeding season. Over-conditioned bulls entering the breeding season may be less active during the breeding season, especially if the breeding season occurs during the heat of summer. The same could be said for under-conditioned bulls in that their activity may be limited.
It is almost like the porridge being to hot, to cold, or just right. The idea is develop and manage young bulls so that they are just right for the breeding season. In other words, they are in their working clothes and toned up ready to perform their duty. In most cases, feeding and managing bulls to be in body condition score 6 (1=emaciated; 9=obese) at the start of their first breeding season is adequate. Body condition score 6 equates to body fat of about 20% to 23%. This body condition isn't different for the target body condition of 1st-calf-heifers at their first calving.
As ADG increases, the amount of feeds high in energy, usually feeds high in starch, in the diet increases. As bulls are fed to a higher ADG, the likelihood of increasing body fat also increases. As bulls are pushed to higher ADG, care must be taken to insure and control digestive upsets that can impact the liver in the form of liver abscesses, feet in the form of founder, and rumen integrity. Not managing the feeding program to eliminate digestive upsets has the potential to reduce the longevity of young bulls.
We have used distillers grains and corn gluten feed in our bull development diets. Distillers grains and corn gluten feed have been used as both a protein and energy source. In the process of producing ethanol and fructose (corn syrup), the starch in corn is removed. The remaining byproduct is greater in protein, energy, and phosphorus compared to corn. Removing some starch in the diet and replacing it with essentially a high fiber energy source reduces the incidence of digestive upsets. In addition, if some corn byproducts are used, it is likely that phosphorus can be removed from the supplement. In most cases calcium will be needed in the supplement. In growing bull diets, it would be critical that the calcium to phosphorus ratio not be below 1.6:1. As always, feeds that are used in the diet need to be priced competitively into the diet.
Care of young bulls after the breeding season is important. Bulls should weigh 75 to 80 percent of their mature weight at the start of the second breeding season. If mature weight of the young bulls is estimated to be 2,000 pounds and at the beginning of their first breeding season they are 1300 (65% of mature weight) pounds and they loose 200 pounds during the first breeding season, then to be 75% to 80% of their mature weight by the start of the next breeding season, it calculates that they need to gain 400 to 500 pounds.
Between the end of their first breeding season and the start of their second breeding season, these young bulls need to gain about 2 lb/day. Native grass quality is peaking and starting on the decline in July and August and bulls will gain about 1.5 lb/da without supplementation. Young bulls will need some supplemental energy and protein before the second breeding season. Consider not trying to wait until right prior to the second breeding season to get young bulls back in their working clothes and at the desirable weight. For a spring breeding season, consider feeding these bulls some protein and energy beginning about Christmas time. Starting this early allows you to put weight back on gradually with smaller amounts of a high energy feed. This doesn't have to be accomplished in a dry lot and could be fed on pasture or when the bulls are grazing corn stalk residue.
This doesn't suggest young bulls be pampered in an artificial environment. It does suggest to at least give them a chance to be productive and remain in the herd as long as you want them there. The bull battery is an expensive investment, manage the young ones so that you get a reasonable return on that investment.
Dr. Rick Rasby, Professor of Animal Science
Animal Science, University of Nebraska–Lincoln, Lincoln, NE