Livestock Management RANCHING
Stages of a Bull’s Production Life By Gary DiGiuseppe
T
HE BULL WILL HAVE A LOT TO DO WHEN HE’S TURNED OUT on pasture. From a nutritional standpoint, it’s best to ease him into it.
Dr. Ben Holland, technical services nutritionist with
Merck Animal Health, says adaptation of the bulls to the environment where they will be turned out to breed is crucial. “Bulls should have adequate body condition prior to the start of the breeding season,” Holland says. “Whether they’re purchased or home-raised, many bulls are developed with relatively high-concentrate dry-lot rations. “To ensure that bulls are best prepared for the
breeding season and the pastures they will be working in, we have to adapt them fairly gradually from those concentrate rations to a forage-based system, and we have to do that relatively slowly over a period of time. “If we have a big adjustment for adaptation — for
example, if they are on the high energy, high con- centrate diet you might see in some bull tests or bull development programs, and then we suddenly send those bulls out into a pasture where they don’t have as much energy available and they must travel greater distances to eat and breed — they can suffer stress and quickly lose condition as they adapt to their new environment. All of these can result in poor semen quality and reproductive performance.” He says dietary adjustments pre-breeding should
be phased in over at least 30 and possibly as many as 45 days.
76 The Cattleman February 2015
According to Holland, there are 5 phases in a bull’s
life from a nutritional standpoint. • Pre-weaning • Post-weaning/prepubertal • Conditioning for the breeding season • Breeding season • Post-breeding
Pre-weaning During the pre-weaning phase, bulls, heifers des-
tined for breeding, and market steers and heifers can all be managed together on the cows. However, once calves are weaned at up to 9 months of age, and per- haps preconditioned, each of these different classes of cattle requires separate management. That is when bulls need to go onto their own pasture, although Holland says retained heifers can remain with market calves until spring or summer.
Post-weaning Holland says that bulls should be fed suffi cient nu-
trients to gain 2 to 3 pounds per day during the post- weaning/prepubertal phase, which lasts from wean- ing until about 30 to 60 days before the fi rst breeding season. (Refer to Chart 1 for details.) “Bulls should be neither too thin nor too fat going
into the breeding season; therefore, moderate growth should be targeted. Two-year-old bulls should be about 75 percent of mature weight, and purchased bulls
thecattlemanmagazine.com
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