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Producers should consider these facts and tips about

by Wyoming Livestock Roundup

bulls as they make this year’s sire purchases 

Regardless of how a producer breeds their cows – artificial insemination (AI) or natural service – they need a good bull, or several, relevant to their number of cows. Even when utilizing AI, it pays to have a good clean-up bull since conception rates with AI are rarely 100 percent. It’s actually closer to 70 or 80 percent.   

Unless cows are calved year-round – an impractical way to manage beef cows – bulls should be kept separate from other cattle, except during breeding season. Many producers don’t want cows bred during the wrong time of year for when they plan to calve, and they don’t want heifers bred too young.  

A young bull will do better if kept separate from cows after breeding season is over. He’s still growing and needs time off from chasing cows so he can regain lost weight and be in better condition for next year.

A pasture for bulls needs good fences. It’s always healthier for bulls to have room to exercise and to be out of the mud in wet seasons, so a pasture is better than a small corral, if there is room.  

Electric wire can augment a pasture fence to make sure bulls don’t try to go through the fence. It also helps if producers have a buffer field or pen between the bull pasture and any females.  

If bulls can’t get nose to nose with females, they are not as tempted to crash a fence.

Bulls need good feed, but this doesn’t mean grain. If a bull needs grain to stay in good body condition, he’s not very feed efficient and won’t sire feed-efficient offspring.  

Many seedstock producers overfeed young beef bulls to get them big enough fast enough – since most bulls are now sold as yearlings rather than two-year-olds – and to have them look good by sale time.  

Fat young bulls often “fall apart” when turned out with cows. They are not in athletic condition and tire readily. They lose weight rapidly due to the sudden drop in nutrition levels, coupled with drastic increase in exertion.  

Overfeeding leads to fertility problems – too much insulating fat in the scrotum keeps it too warm for optimum sperm production and viability – founder and other feet and leg problems.  

A yearling bull needs adequate nutrition for growth, but this can be provided with good pasture or good quality hay with an adequate protein level. Mature bulls should do fine on pasture or good grass hay or a grass-alfalfa mix.  

Watch body condition and adjust the feed accordingly.  

If older bulls get too fat, this not only hinders fertility but can also impair athletic ability, stamina and sex drive. 

If bulls start losing weight, increase the quantity or quality of feed. A good mineral supplement is also important for optimum fertility, if feeds are deficient.

Bulls are bulls 

Handle bulls with firmness and respect and never forget they are bulls – their instinct is to dominate other animals. 

Don’t make a pet of any bull. If he looks upon a human as an equal and has no fear/respect, he may eventually become dangerous as he gets older and more aggressive.  In his mind, he must always be the dominant member of the team, never to be challenged.  

Sometimes it helps to carry a stock stick when handling bulls on foot, such as working or sorting them in a corral, but producers should rarely have to use it if they keep a confident attitude.  

If a bull respects an individual, they generally don’t need to use a stick. 

Some bulls become aggressive at a young age and others become more aggressive as they get older. Most bulls will start questioning authority by the time they are four or five years old, though a few remain mellow and manageable for longer.  

If a bull starts challenging a producer’s authority, they should get rid of him.

Selecting a bull

A bull provides one-half of the genetics for any calves a producer sells or keeps as future cows, so it is important to find a good bull that suits the goals of an operation.  

If the bull is purebred, 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, and check his projected birth weights to make sure he’ll sire small calves that are easy born but grow fast.  

Birth weight is partly a result of gestation length, which is a heritable trait.  

Evaluate him visually to make sure he has good conformation and will stay sound, siring daughters with good conformation. 

He should have strong feet and legs – good bone and strong hoofs – not crooked or weak and should travel well, with legs moving straight forward instead of crookedly. 

If he has too much angle in his hind legs – sickle hocks – or not enough angle in hocks and stifles – post-legged – he may suffer strain and injury when trying to breed cows. He should have a strong back – not sway-backed nor humped up – and be long in body, not pot-bellied.  

If an individual plans to keep daughters as future cows, they should always look at the bull’s mother, especially her udder shape, milking ability, etc. His daughters will be a lot like the mother of the bull.  

If she has faults – big teats at calving time, bad disposition, etc. – they likely will too.

Make sure he has a good disposition and is easy to handle. Temperament is partly inherited. Producers want a bull that not only sires easy-born, fast-growing calves and good-milking daughters, but also passes on a calm, intelligent behavior.  

How producers handle and train their 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 and mean or wild and flighty bull will sire calves with the same bad attitude. They will be difficult to handle, more easily stressed and won’t gain weight as readily as calmer individuals.  

Never use a bull with traits one wouldn’t want in their calves or in daughters they might keep as cows.

Considerations prior to turnout

Always have a breeding soundness exam (BSE) performed before the breeding season, to check semen and any other factors which 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 which might be prevalent in the region.

Vaccinate bulls annually or semi-annually for some diseases and make sure vaccinations are current ahead of breeding season by at least three weeks. 

Have a local vet perform a BSE and semen check, even if the bull was fine last year. The bull may have suffered injury or infection between then and now, and it is important to make sure he’ll be fertile and able to breed cows.

Heather Smith Thomas is a corresponding writer for the Wyoming Livestock Roundup. Send comments on this article to

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