Editor's note: Numerous studies have shown the economic advantages of artificial insemination over natural service. However, realizing that some of our readers are still using herd bulls or making transitional steps to AI, we have decided to run the following column on managing the bulls properly.
Use the following checklist – compiled from dairy producers and veterinarians – to ensure safety and profitability when using a natural-service sire:
Human safety management
Over the years, we have all heard of stories where bulls have hurt and even killed people. Last year in my practice alone, bulls caused serious injures to three people. This is a serious consideration if you use natural-service breeding. Remember, all bulls will eventually injure someone if given the opportunity. Don't think it will never happen on your farm. Consider:
- No children should be allowed in a pen or barnyard with an unrestrained bull.
- Never tease or taunt a bull.
- Do not try to make them into pets. A "tame" bull will eventually turn on you.
- Always have a safe distance between you and the bull. Don't turn your back.
- Dehorn all bulls and put in a nose ring for handling when necessary.
- Buy only young bulls and sell by two years of age before aggressive behavior begins.
- Sell immediately if any aggressive or unfriendly behavior is noticed.
Breeding bulls will do well consuming a nutritionally-balanced milk cow ration. Certainly, their maintenance and growth requirements are less than a producing dairy cow, but their dry matter intake is only about one-half of a typical milking cow. Therefore, free-choice milk cow TMR is satisfactory.
Often, questions are raised about fertility in bulls consuming whole cottonseed. This concern is due to research showing gossypol (a toxin sometimes found in cottonseed) decreases sperm development. However, this research has not shown gossypol toxicity to cause problems in field situations where known high levels of gossypol are being fed.
Health and reproduction
Farm biosecurity, milking herd pregnancy status, and bull health all need to be examined. Bull breeding will not cause any problems in these areas if managed properly. Following some simple common-sense guidelines can prevent many health or reproduction disasters:
- Purchase young "virgin" service sires from a reputable herd.
- Be aware of the contagious disease status in the herd of origin.
- Follow all regulatory testing guidelines established by your state animal health department.
- Discuss with your veterinarian a herd vaccination protocol for preventative disease control.
- Request a veterinary Breeding Soundness Exam prior to use.
- Monitor feet and legs closely. Trim feet on a regular basis. If lameness occurs, the bull should be removed from the herd immediately and given stall rest until completely healed.
- Use one bull per 25 open cows.
- Conduct pregnancy exams quickly when a new bull begins breeding cows in the herd to monitor fertility.
Dr. Robert Fry is a veterinarian and operates Atlantic Dairy Management Services in Chestertown, Md.