Cut the Bull

Every year the Hereford bulls at Timberline Ranch go through a breeding soundness exam prior to turnout. So when Kenneth Allen started to look for reasons conception rates on his Brahman cows were hitting between 70% and 75%, the last place he expected to find a problem was in the bull pen.

"I was raised with Brahman cattle, and that conception rate was just too low for me," said Allen, who has been ranch manager at Timberline since 1990.

The picturesque, rolling ranch is based in Tyler County, Texas, just outside of Woodville. It's home to about 400 gray Brahman cows, and carries both a fall- and a spring-calving herd. The focus here is primarily on raising F1 Braford replacement heifers. Every open cow is a market opportunity lost, and the need to improve conception rates was at the top of Allen's list. He initially thought the problem had to be the cows.

TEAM EFFORT

Polk County extension agent Mark Currie has a long friendship and working relationship with Allen. He encouraged the rancher to participate in the state's Beef PEP program, hoping they could quickly find some solid answers to the herd's conception issues.

Beef PEP (Partnership in Extension Program) is a one-on-one program, bringing together ranchers with an elite team of specialists from the Texas A&M Agrilife Extension Service. Herds are chosen for the program, with each herd manager or owner committing to three years of working with the Beef PEP team. Experts are from the areas of forage, economics and animal health.

Currie said they found nothing on the cow side in the Timberline herd that would explain the low conception rates. So they went back to the bulls to examine the thoroughness of past breeding soundness exams.

"What we found was the exams were looking at the motility of the sperm but not the morphology," he said. "There was movement, but some of the bulls failed the morphology part of the exam. They weren't necessarily infertile, but they were definitely sub-fertile."

Poor sperm morphology refers to cells that are considered abnormal, in terms of shape and size. As the percentage of the abnormal population increases, fertility may decrease. The other common term used in determining bull fertility is "motility," which refers to movement of the sperm.

TIME TO CULL

Out of 18 bulls, 6 were culled from Timberline's herd in 2010 and replaced with bulls that passed the fertility test. As a result, in just one year, conception rates were up 11% and herd value increased an estimated $30,000. That figure was calculated by Stan Bevers, the AgriLife Extension economist who runs all the data from Beef PEP herds through a Standardized Performance Analysis tool. This economic program generates specific numbers that show a producer how much each cow in the herd generates in sales and profits.

An 11% increase in conception rates in one year was a good start, said Allen. But he wants to see those numbers go even higher.

He's increased his vigilance on Body Condition Scores and breedback on the cow side. Working with Currie and the rest of the PEP team, Allen is tracking BCS data every time a cow goes through the chute.

"Conception rates have a direct impact on the bottom line," he said. "So we want to know the body condition on all our cows year round, not just at time of breeding. Every time we work them, we take a score and record it. We like to see them all around a six, year round."

Currie says coming out of the winter it's not uncommon for body conditions on cows to drop to a five or even less. He cautions producers against getting scores lower than a five, but adds don't assume more is always better. In most cases, trying to take cows above a seven isn't economically feasible.

"There's no reason to try to make eights out of them," Currie said. "We try to stay between that five and seven mark. To optimize reproduction we want mature cows in a BCS of five or greater at calving."

This winter Currie expects most cattlemen in his part of Texas will have sufficient forage supplies, thanks to good moisture in spring 2013. As summer moved in, however, the rains dried up and grazing and hay production suffered. The variation throughout the growing season means hay quality will vary widely.

Currie said without knowing hay quality, it's challenging to maintain body condition on a cow. A lactating cow, for example, needs a diet that's 11% to 12% crude protein and 60% to 63% total digestible nutrients. On the other hand, a dry, pregnant cow needs 7% to 9% CP and 50 to 55% TDN. The only way to know where hay quality falls is to test it.

"Never assume it's OK. The only way to know what you have is to pull samples and get forage tests. Otherwise you're just guessing," says Currie.

FERTILITY TEST YOUR BULLS

Every single year, every single bull needs to go through a breeding soundness exam with your local veterinarian. Put it on the calendar about 60 to 75 days before turning the bull in with the cows. This gives you time to replace an infertile, or sub-fertile bull, before it can hurt conception rates.

What should that exam, for which you're spending good money, include? Alabama veterinarian and cattleman Ken McMillan, who writes the "Ask the Vet" column for The Progressive Farmer magazine, has addressed the question in previous columns. But he said it's good to remember that every exam cover these items.

-- Structural soundness. This is a look at the overall condition of the bull and should include everything from feet and legs to eyes and teeth.

-- Reproductive system. The scrotum, testicles and penis are checked. Scrotal circumference should meet minimum requirements (30 centimeters for a yearling bull; 34 centimeters for a mature bull). The veterinarian should also do a rectal palpation to see if there are any internal abnormalities.

-- Semen quality. Semen needs to be collected and checked for motility, morphology and overall production.

After the exam a veterinarian will generally classify a bull as "satisfactory," "unsatisfactory" or "suspect." Most will make recommendations regarding retaining or culling the bull. Young bulls sometimes fail their initial test and should be retested again later. Mature bulls, however, generally don't get a second chance.

(VM/CZ)

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