by: Heather Smith Thomas

Selecting A Bull

A bull provides half the genetics for any calves you sell, or the heifers you'll keep as future cows, so you want to make sure you select a good bull that suits your goals. If he's registered with a breed association, check his performance records and those of his sire and dam, to know what to expect from his calves regarding birth weight, weaning weight, etc. If he'll be breeding heifers, make sure he isn't too large and heavy or he may injure them during breeding. Check his projected birth weights to make sure he'll sire small calves that are easy-born but grow fast. Calf birth weight is partly a result of gestation length, which is a heritable trait.

Evaluate the bull visually to make sure he has good conformation and will stay sound. If he is structurally correct, he will likely to sire daughters with good conformation. He should have strong feet and legs, good bone and strong hoofs. You don't want a bull with legs that are crooked or weak. He should travel well, with legs moving straight forward instead of crookedly.

If he has too much angle in his hind legs, a condition called sickle hocks, or not enough angle in his hocks and stifles, a condition termed post-legged, he may suffer strain and injury when trying to breed cows. He should have a strong back. He should not be sway-backed nor humped up. A good bull is long in body and not pot-bellied. If he's sway-backed, with a high tail-head (pelvis tipped up at the rear), his daughters may also have a tipped-up pelvis — which can lead to calving difficulty.

If you'll be keeping daughters as future cows, always look at the bull's mother — especially her udder shape, milking ability, etc. His daughters will be a lot like his mother. If she has serious faults such as big teats at calving time, fertility problems, bad disposition, or other undesirable traits, the bull's daughters likely will, too.

Make sure he has a good disposition and is easy to handle. Temperament is partly inherited. You want a bull that not only sires easy-born, fast-growing calves and good-milking daughters, but also passes calm, intelligent behavior to his offspring. How you handle and train your cattle can make a big difference in tractability, but it helps if they have good intelligence and an easy-going nature to begin with. An aggressive/mean or wild/ flighty bull will sire calves with the same bad attitude. They will be difficult to handle, more easily stressed, and they won't gain weight as readily as calmer individuals. Never use a bull that has traits you wouldn't want to see in the calves or in his daughters you might keep as cows.

Before you bring home a bull always have a breeding soundness exam to check his semen and any other factors that might affect his fertility or breeding ability. Unless he's a virgin bull, he should also be tested for trichomoniasis and any other sexually transmitted diseases that might be prevalent in your region.

Vaccinate your bulls annually (or semi-annually, for some diseases) and make sure vaccinations are current ahead of breeding season. Bulls should be vaccinated at least three weeks ahead of when you plan to turn them out with the cows. Have your vet do a breeding soundness exam, trichomoniasis test and semen check, even if the bull was fine last year. The bull may have suffered injury or infection between then and now; you want to make sure he'll be fertile and able to breed cows.

Reproductive Behavior

When a cow comes into heat she will seek a bull and start mounting him and other cows, but it may still be a few hours before she will stand for the bull to mount and breed her. She will generally stand for cows to mount before she will be in a strong standing heat for the bull to breed her.

Bulls are continually traveling through the herd, checking cows to detect the ones that are in heat or coming into heat. A bull smells the vulva of a cow and also smells her urine. During heat a cow urinates frequently and the bull samples the odor and taste of her urine. The in-heat cow releases pheromones in body fluids, especially her urine and sweat glands in the flank area, and he can detect those.

Pheromones are chemical substances secreted by animals, to send messages to other animals of their species. A bull may be able to smell an in-heat cow some distance away if a breeze brings odors his direction. Bulls can often identify a cow in pre-heat up to two days before she actually comes into heat. A bull may keep close track of her -- staying near and guarding her from other bulls -- until she does come into heat.

He makes tentative attempts to mount the cow but if it's still early in her heat period she may not stand. He keeps checking her by resting his chin on her back or rump, and only mounts and breeds her when she is ready and holds her back rigid.

If he actually breeds her, the cow will then stand humped up, with her tail raised, after he dismounts. If the bull merely mounts and dismounts and the cow does not hold her tail out afterward, this is a clue that the bull did not ejaculate; the cow was not actually bred. If a bull is tired, he may mount a cow repeatedly but not actually breed her. A close observation of the herd, or even a good look at the cows several times a day can give a clue as to which ones were bred, enabling you to record projected calving dates on those cows for next calving season.

If the cattle are on range or large pastures and you're unable to observe the breeding activity daily, you won't know which cows are pregnant or “open,” or when they might be due to calve, unless you later observe an open cow in heat after the breeding season is over. It's always wise to have cows pregnancy checked a few months after the breeding season, to know if there are any that didn't settle and should be culled.

Cows can be checked for pregnancy via blood test, ultrasound or rectal palpation. A veterinarian who is experienced at ultrasound or palpation can give you a good estimate of the stage of gestation if a cow is pregnant — which gives a rough idea of when she will calve. If a high number of cows are open, you should work with your vet to determine whether this is due to disease, a nutritional issue, or an infertile bull.

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