Feeding and managing young bulls for optimum fertility and longevity
January 18, 2018
For many years, most seedstock breeders overfed young bulls, often putting them on high concentrate rations for feed trials to see how much they could gain in a short time. Some bulls were gaining four or more pounds per day, which can be detrimental to future fertility and soundness.
Although most stockmen realize fat is unhealthy for a bull, they still tend to buy the biggest, best-looking animals, and many breeders keep overfeeding them because it's harder to sell a bull that isn't carrying extra weight.
John P. Kastelic, DVM, PhD, cattle reproductive health, University of Calgary has done many studies on nutrition in bulls. "We started out many years ago with research on beef bulls. In beef bulls historically people focused on nutrition after weaning. There has been extensive study on that, going back to the 1970s when Dr. Glenn Coulter (my former colleague at the Lethbridge Research Centre) and other people did a lot of the research," says Kastelic.
"Back then, seedstock producers fed their young bulls practically a feedlot ration, to achieve impressive gains and see how fast they gained. There is good evidence to show that if you feed bulls high-energy diets after weaning, you get very rapid weight gain but you also create a lot of problems with excessive fat in the scrotum, reduction in semen quality, more risk for laminitis/founder, liver abscesses, rumenitis, etc. Feeding young bulls this much is counterproductive." Producers are recognizing this and realize that a bull should be fed for a long life of breeding rather than fed like a steer destined for slaughter. A bull needs to be athletic, not fat.
"The thinking used to be that if a bull is not fat he must be a hard keeper and poor doer. Sale bulls were always fat but producers thought they could just take them home and put them on a diet before they put them out with cows and they would be in breeding shape. Unfortunately, some of the damage in the overfat young bull can be permanent," says Kastelic.
These bulls can end up with liver abscesses, damaged claws and feet, and in some cases permanent reduction in number of sperm produced and often poor semen quality. "There is no sense in grossly overfeeding bulls in the post-weaning period," he says.
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Even though most seedstock producers realize this, many bulls are still fed to be a little too fat. Buyers realize a bull should be fit, not fat, but they still tend to think there is something wrong with a bull that's not carrying extra weight at sale time.
According to Duane Mickelsen, DVM, a cattle breeder near Pullman, Washington (retired from the faculty at Washington State University, where he did fertility studies in beef cattle for many years, and thousands of breeding soundness exams on bulls) says most purebred breeders are going away from this type of overfeeding because they now realize the permanent damage that can be done. Young bulls are more often raised in larger pastures with more exercise, and fed a growing ration instead of a "hot" ration like a finishing steer.
"The genetics we have today are also a factor; most of the cattle being bred now can grow well without as much over-feeding," says Mickelsen. Feed and management of these young bulls is very important, however, to ensure that they can stay sound and fertile.
Mark and Della Ehlke raise purebred Herefords and Angus near Townsend, Montana. They have a spring and a fall calving herd; they manage each of those groups a little differently.
The spring-born bulls are weaned early. Then through winter they are fed at a neighbor's feedlot, who raises registered Red Angus. "Together we've come up with a target goal of having them gain about three pounds a day, and we don't get too aggressive. Through the years, this is about what these pens of bulls will do. Obviously some individuals will gain a little more than three pounds a day and some will gain a little less," Mark says.
This still sorts out the most efficient ones. "We've had good luck with this program in terms of bulls maintaining soundness," he says.
The feedlot has large pens and the bulls get some exercise. The pens are on a slope and they have to travel up and down. They are fed a ration that contains chopped hay and straw, along with a bull developer pellet. This program has worked very well for spring-born bulls, for about 20 years.
The fall-born calves are all developed on grass through the summer. The Ehlke pastures contain some legumes and provide adequate nutrition. Young bulls will gain at least 3 pounds a day just on pasture and also have plenty of exercise.
This is an ideal situation for growing bulls. "We really like fall calving for developing those calves. By the time we wean them there's green grass coming and we just turn them out and let them grow," says Ehlke.
"When growing bulls, it's important that the ration is geared toward longevity and soundness as well as growth and gain. We want to avoid laminitis and feet problems. We don't have the fattest bulls in the spring, but hopefully they'll be good ones. Through the years we've had very few complaints in terms of soundness; we have customers who run our bulls until they are 5 or 6 years old."
Jack Holden of Holden Herefords, Valier, Montana, raises registered Herefords in northwestern Montana. "In our program, we want to give young bulls every chance to exhibit their performance, but at the same time keep them sound and not too fat. We feed a high-fiber low-fat ration, a wheat mid based pellet. We've had good luck with this because it has a lot of roughage/fiber in it," he says.
"Our bulls are on a 130 to 140-day gain test on this feed, then the 70 days before they go into our sale we feed more hay and just coast them so they can make a transition to grass and not melt." This also enables rumen microbes to change from the more concentrated ration to grass (cellulose) more easily than from a higher starch diet.
"What we've used for many years that really helps these young bulls is flax based lick supplements. We put tubs out for them, and found that this supplement helps with scrotal development and semen quality," he says.
Feeding young bulls is always a balancing act, walking a fine line between over-feeding and providing nutrition for optimum growth. "We try to get as much growth on them as we can while at the same time keeping them right. Some of this involves genetics and genetic selection. There are some cattle that can handle a little more feed and performance and still stay sound and fertile, while others can't," says Holden.
He thinks most breeders have backed off a little in how much they feed young bulls, but buyers who come to a sale still want to see the bulls looking shiny and big. "There are so many different ration possibilities now, with all the distiller grains and by-products for people to use. It's just a matter of working with a nutritionist and coming up with a program that works, and you can fine-tune it as you go," he says.
"In our case we've been on the same kind of pellets and feed program for almost 20 years and we know what kind of gains we'll get. We've done some fine-tuning over the years, to minimize bloat issues or digestive problems, and have backed our gains off just a little," he says.
The bulls are weighed a couple times while on test, to see how they are doing as a group, and as individuals, to know if feed should be adjusted to have them gaining a little more or a little less. "The bulls are continually monitored; your eye will tell you a lot," he says.
Feeding a moderate ration and not pushing them too much helps avoid foot problems and fat in the scrotum (which interferes with fertility). "We want to feed them almost to that limit, to find the bulls that can gain well and stay sound." They sort themselves out, in terms of which ones can do it. As a group it's easy to see which ones have the performance and the ability to stay sound. He feels that breeders need to give bulls a chance to perform but not cross the line and feed too much. Even though they are not being pushed as hard as some did in the past, you can compare them to each other as a group and know which ones are the top performers.