BULLS

coming 2 and 3-year-olds di erent from the way they feed the main herd. Pay attention to body condition score, especially in young cows,” says Williams. They should be kept separate and fed di erently, preferably before they’ve lost weight.

“If an older cow is losing weight, she should also be pulled out of the herd and fed di erently. Some producers put their old, thin cows with the young cows— whatever works for their operation,” she says. Protein requirements for pregnant cows increases during later stages of gestation, and is even higher for young cows. If you are keeping the young cows (coming first and second calvers) separate, they can be supplemented with protein, if necessary, without having to supplement the whole herd.

Mature bulls need adequate nutrition for maintenance and body heat. No bull—young or old— should be overfed to the point of being too fat. Grant Lastiwka (Livestock and Forage Business Specialist, Alberta Agriculture), says it is important to grow young bulls properly with the correct level of protein, energy and minerals (and not overfeeding). The older bulls that just need maintenance rations during winter can easily become too fat and heavy over winter. “They need to be out exercising rather than confined, but we can provide windbreaks and bedding,” he says.

Bulls need enough groceries to grow and develop properly, with enough energy to facilitate growth and have a bit extra. “As they get older, however, their requirements are just for maintenance; we just need to make sure they have adequate body condition when they go out to breed. Ours go out August 10 so they’ve had most of the summer to graze. The older bulls can get very fat, which is a challenge,” he says.

“If you are running mature bulls in a setting where they are just on maintenance rations during winter with a bit to spare, what you feed will depend on the condition they are in coming into winter. Some of the younger bulls may start the winter in poor condition because they’ve been breeding cows all fall, and maybe they are shedding their teeth (which happens at about 2 years of age when baby teeth are shed, and their permanent teeth are coming in) and not eating as well as they should.”

How you separate bulls and feed them during winter depends on how many bulls you have, their ages and condition. “Often bulls simply need a maintenance ration. This can be provided with stockpiled forages, swath grazing, bale grazing etc. Depending on what you are doing with them, they can do very well in winter out in big pastures,” says Lastiwka.

“According to the University of Idaho’s Cattle Producer’s Library, Cow-Calf Management Guide, a mature 1100-pound cow needs 7.8% of the diet to be crude protein during the last trimester of pregnancy. A 900-pound yearling heifer (coming 2 year old, approaching her first calving) in her last trimester would need 9% to 10% crude protein. Another thing that’s di erent between the heifer and a mature cow is energy needed for maintenance,” says Williams.

Mature cows can be roughed through winter and early spring (till they approach calving) a lot easier than younger cows, because they are not trying to grow. “Percent TDN for a 900-pound heifer is 65.4% compared with 53.2% for an 1100-pound cow during her last trimester. This is a major difference. You wouldn’t need to