MANAGEMENT COMPONENTS

SECTION 6. CARE OF THE DAIRY BULL

Bulls of various ages are common on dairies. Management practices including feeding and nutrition, health, and housing requirements from birth to puberty are similar to those for raising heifers (see Section 1). Bulls may be housed with growing heifers of similar age prior to reaching puberty. After puberty, bulls should be raised in separate pens from the heifers.

Many dairies use bulls to breed cows that did not conceive with artificial insemination (AI), were not detected in heat and bred by AI, or aborted early in gestation. These bulls are referred to as 'clean-up bulls,' and they are housed with cows in group corrals. Clean-up bulls are often purchased from registered breeders to provide superior genetics for the herd. Some bulls used for natural service also may have had semen collected and distributed to other dairies for AI. The progeny from these matings allow evaluation of the bull based on the performance of his progeny. Bulls with superior genetic potential will then leave the dairy and enter a commercial AI organization. Bulls that are no longer needed for breeding are sold for meat.

Bulls are large, powerful animals and handlers should always be cautious. Most dairy producers sell bulls for slaughter when they become aggressive or too large. Consequently, most clean-up bulls are two years old or younger. Breeding bulls can be housed in open corrals or freestall barns with lactating cows. In some areas, pasture breeding is practiced and, thus, bulls remain on pasture. Corral fences and gates used for the milking herd are usually adequate for bulls. Likewise, shade, free stalls, water access, and feed bunk space requirements which are adequate for lactating cows are usually satisfactory for bulls.

Some bulls are housed on the dairy waiting for progeny performance information before acceptance into an AI program. Other bulls are sold specifically for natural service purposes. Bulls waiting for acceptance by an AI program are often housed in individual pens that provide adequate space for the bull to move freely (rise, stand, walk, and lie down) and provide protection from mud and rain.

The decision on construction material for pens must consider the size and strength of the bull. Many pens are constructed of pipe, although wood also is used. The pipe must be stronger than pipe used for the lactating cows. Four-inch boiler pipe is considered adequate. The best designed facilities have pipes attached to metal posts which are set in concrete for strength. The interior should be safe for the animal and attendants, with no protruding pipes or sharp edges.

As a safety factor, the bull facility design should allow attendants to feed and water the animal without entering the pen. Bull pens should be designed to allow rapid escape for the attendants if they must enter the pen. Most pens are equipped with water bowls or troughs. The surface of the pen may be dirt or concrete. Dirt pens often provide better footing, but concrete pens are also suitable if adequate bedding is provided. Concrete surfaces should not be so smooth that footing or traction is impaired or so rough that hoof bruising occurs. The bull pens should be situated so bulls can be moved safely using existing walkways or alleys. Some pens include stanchions or head gates for restraint, although these are not a necessity.

The feeding and nutrition programs for growing bulls should meet requirements specified in the Nutrient Requirements of Dairy Cattle (NRC, 1989) publication. Most breeding age bulls, approximately 8 months and older, are housed with lactating cows and are fed the same diets. Diets fed to lactating dairy cows (NRC, 1989) will meet or exceed the energy and nutrient requirements of the growing bull. The lactating cow diet allows for maintenance and growth as well as the increase in activity associated with breeding. Long-term access to a lactating cow diet may cause calcification of soft tissues due to the high calcium intake. This is normally not a significant concern since most bulls do not remain on the dairy long enough to reach maturity. Mature bulls should be fed diets according to the NRC (1989) recommendations. All bulls should have free access to clean, fresh water.

Nose Rings

Some bulls have rings placed in their noses between 9 to 12 months of age. A self-piercing, non-rusting metal ring is inserted through the nasal septum that separates the nostrils about one inch from the tip of the nose. The procedure can be conducted by trained dairy personnel or a veterinarian. Once the nose ring is inserted, a bull staff can be used by the attendant to help control the animal.

Preventative Health Program

A preventative health program for bulls should be established in consultation with the herd veterinarian. A health program should consider deworming, particularly for bulls on pasture, routine foot trimming, and vaccination programs. Bulls should be

vaccinated for Infectious Bovine Rhinotracheitis (IBR), Bovine Viral Diarrhea (BVD), Bovine Respiratory Syncytial Virus (BRSV), leptospirosis, and vibriosis. It is a good practice to have the herd veterinarian conduct a breeding soundness examination on dairies where facilities are adequate to safely restrain the bulls. This examination includes a microscopic examination of semen quality and a physical examination for signs of testicular and other reproductive abnormalities. Bulls should also be tested for trichomoniasis at this time. Trichomoniasis and vibriosis are venereal diseases, and cows can be infected by the bull during breeding.

Most routine health care should be similar to that provided to other animals on the dairy. Attendants should observe bulls for any health problems, and appropriate action should be taken when necessary. Bulls can be aggressive, so they must be handled carefully.

Transportation

Transporting bulls requires care because of their size and temperament. Bulls are often transported individually due to their aggressive nature. Because of their size and weight, bulls that are incapable of standing require special attention. Transportation and the care of non-ambulatory or disabled animals are discussed in Section 7, and these suggestions apply to dairy bulls.

Construction of bull pens should consider the size and strength of the bull.