Posted: Thursday, December 17, 2009 10:00 AM
Reducing stress benefits cattle, specialist says
By DEAN REA
For the Capital Press
HALSEY, Ore. -- Improving the temperament of a cow herd can benefit production and can increase fertility, an Oregon State University Extension beef cattle specialist says.
It doesn't help to use dogs to round up the cattle and a cattle prod to force them into a chute, said Reinaldo Cooke, who is based in Burns, Ore.
Cooke, who earned a doctorate in animal sciences a year ago from the University of Florida, was hired early this year to build a research and extension program to meet the needs of beef cattle producers in Oregon.
Cattle, like humans, are stressed when they move outside their comfort zone, Cooke told the a group of Linn and Benton county livestock producers Dec. 8 in Halsey.
"Cattle are stressed when exposed to human handling," Cooke said, noting this may occur when cattle are placed in pens, are restrained in chutes and are approached by people, dogs and predators.
Cooke worked with cattle in his native Brazil, where he attended college before completing his education in Florida. Cooke said he has continued his research in Eastern Oregon, where stress among heifers and adult cows was measured while testing 450 animals in April. The tests included stress while entering and leaving a chute and measuring levels of cortisol, a stress hormone that increases blood pressure and blood sugar and reduces immune response.
Pregnancy rates may decrease if a cow is unaccustomed to entering pen or a chute, he said. The Eastern Oregon tests showed that the probability of a pregnancy was nearly 90 percent among low-stressed cows, but as low as 65 percent among high-stressed animals.
Stress can increase the level of cortisol, which Cooke said can lead to a cow aborting a calf. Stress also impacts animal health and carcass quality, he said.
"The only time you can mold temperament is when they are young," Cooke said of animals he has worked with in Eastern Oregon and during his Florida research. Researchers there worked with animals at an early age, weaned calves at six to seven months of age and then took them to cow pens where they interacted with people. Researchers found that this process accelerated puberty and resulted in higher pregnancy rates.
Cooke said he plans to create videos that will help producers measure temperament in their beef herds.
Meanwhile, Cooke suggested that producers get rid of "crazy" cows, which he said can injure a person, and those that appear too docile to fend off predators.