Goals for wintering or preparing bulls for the next breeding season are:
- Achieve/maintain fertility
- Achieve/maintain proper breeding weight and body condition score
- Achieve/maintain soundness and the physical ability to breed
The first concern is the protection of testicles and other reproductive anatomy. In the case of severe, cold weather, protection from wind and cold temperature is warranted. Vaccination programs, designed by your consulting veterinarian, should be implemented.
Since breeding seasons oftentimes cause substantial weight loss, bulls should be fed to achieve the next target weight and body condition for the start of subsequent breeding seasons. The rule of thumb is that yearling bulls should be near 65% of their mature weight when first turned out. Two-year-old bulls should be 80% of mature weight and three-olds very near their mature weights. Bulls should have a body condition score of 5 or 6 (moderate levels) by 30 days prior to breeding seasons. Therefore, weight gains during the off seasons can vary between 0 and greater than 2.5 pounds per day depending on the length of the rest period. Young bulls may need special attention because they are still growing.
Exercise is important. The bulls need to have ample space to allow for social interaction, if housed as a group, and to become physically fit. Ground slope, terrain, and soil type will influence the area needed per animal. Typically, bulls will need greater than 300 square feet per bull for housing.
All bulls should have access at all times to a high-quality mineral mix. Phosphorus is a critical mineral for successful reproduction and is not present in adequate amounts in dry or harvested forage. Good sources of supplemental phosphorus are monocalcium phosphate or dicalcium phosphate. These can be mixed with trace mineral salt in equal parts or two parts salt to one part mineral. Vitamin A nutrition also is important to the resting bull. Natural sources are green growing plants or high-quality hay with good green color. Supplemental vitamin A can be added to the mineral mix or fed with a supplement
Mature bulls in good condition can exist very well on an essentially all-roughage diet. While the amount will vary some with the size of the cattle, a good rule to remember is about 2 percent of their body weight in dry feed per day. Protein needs will parallel closely those of a dry, pregnant, mature cow in the middle-third of gestation, so protein can be supplemented as needed. Extra care and feed of yearling bulls after the breeding season will result in stronger, more attractive mature bulls. If a two-year-old bull weighs will probably need to gain about 1 pound per day if he has been developed properly. These bulls may need 35 pounds of feed or more, of which 8 to 12 pounds should be grain. If body condition is at a BCS of 5 or below, the amount of grain will need to be increased to near 1 pound or more per 100 pounds of body weight. Again, make any increases in grain intake gradually so that digestive disorders are unlikely. Continue to monitor the total protein content of the diet and keep the concentration of crude protein near 12%. Depending on the forage available, this again may require protein supplements which may be included in the grain mix. Monitor the body condition of the bulls closely, and make grain feeding adjustments to reach the body condition score of 6 before the next breeding season begins. This is critical if the bulls will be used once again in a fall breeding season. It won't hurt the mature bulls to get some grain, but do not overcondition the bulls and get them fat or founder the bulls.
Bulls can be fed in a bunk, but there needs to be at least 36 to 40 inches per bull and plenty of bunk space so that the dominant bull(s) doesn't overeat. Some producers will put grain into their cake feeder, and put the grain on the ground in different spots for the number of bulls that are in the pasture. They have a good idea what a pile of 10 pounds of grain on the ground looks like.
