- Plan to have bull sterility examination (BSE) completed each year at least three months before breeding season. This leaves time to recheck questionable bulls and locate replacements if necessary.
- Heat stress and fever affect quality of semen. Temperatures and humidity June through August can reduce fertility of Bos tarus bulls prone to suffer the effects of heat stress. Avoid having to breed cows during the heat of summer. Chronic hyperthermia in modern, large framed bulls occurs when the environmental heat index remains above 82 degrees day after day. Affected bulls stay in shade all day; breath faster than normal; have open mouth breathing and a rectal temperature of 104 to 106 degrees. Affected bulls graze less, lose weight, become weak, and may die unless effectively cooled by rain and wind or by use of large fans and frequent wetting of the skin. Heat stress may reduce number of sperm and fertility rates significantly for up to six weeks after recovery.
- Young bulls need to gain up to 2.5 pounds per day from weaning to 15 months. Growth should continue at 2.0 to 2.5 pounds per day until three years of age. Supplemental feed should be fed to young bulls during breeding season. Mature bulls may need supplement if pasture forage is not adequate in order to maintain a body condition score (BCS) of 6. BCS of 6 is considered optimum body condition for breeding performance. A time honored ration for wintering bulls consists of 12 to 15 pounds per day of a feed containing:
- 40% cottonseed hulls
- 30% crushed corn
- 15% wheat bran
- 15% cottonseed meal
A commercial bull developer feed may do just as well. These suggested concentrate feed levels assume adequate intake of reasonably good quality forage or hay.
- Young bulls may need deworming four times per year. Bulls of any age that were raised west of I-35 then moved into Louisiana are at danger of severe parasitism from the brown stomach worm and from liver flukes (marsh, river bottom land). Horn fly control is essential because bulls seem to attract more than their share of these pests.
- Vaccination of bulls should include anaplasmosis, IBR-BVD, leptospirosis, campylobacter (vibrio) and, in some situations, trichomonas. Multiple blackleg-enterotoxemia type vaccination is recommended. Annual, or more frequent, vaccinations suggested.