Selecting against ill-tempered cows has always made good sense because wild cattle are hard on equipment, people, other cattle, and now we know they are hard on the bottom line, said Glenn Selk, Oklahoma State University Agricultural Economist in a letter to Extension agents called Cow/Calf Corner.
October is a traditional weaning and culling time for spring-calving herds, Selk said. It also is a time when producers decide which cows no longer are helpful to the operation and which heifers will be kept for replacements.
MEASURE WHAT WE’VE ALWAYS KNOWN
University of Florida animal scientists recorded disposition scores over two years on 160 Braford and 235 Brahman x British crossbred cows, he said. They wanted to evaluate the effects of cow temperament and energy status on the probability to become pregnant during a 90-day natural breeding season.
Cows were scored as 1= calm, no movement to 5= violent and continuous struggling while in a working chute, Selk said. A pen score assessment also was assigned as 1= unalarmed and unexcited to 5= very excited and aggressive toward a technician.
An chute-exit velocity score was given as 1= slowest and 5= fastest, he said. An overall temperament index score was calculated by averaging the chute, pen and exit velocity scores.
Blood samples were analyzed for cortisol concentrations, Selk said. Cortisol is a hormone released when mammals are stressed or excited. Increased cow temperament score and elevated cortisol concentrations were associated with decreased probability of pregnancy.
Those results suggest that excitable temperament and the subsequent elevated cortisol concentrations are detrimental to reproductive function of cows, Selk said. The Florida University authors concluded that management strategies that improve cow disposition, enhance their immune status and maintain the cow herd at adequate levels of nutrition are required for optimal reproductive performance.
ANOTHER STUDY
Mississippi State University researchers used a total of 210 feeder cattle consigned by 19 producers in a “Farm to Feedlot” program to evaluate the effect of temperament on performance, carcass characteristics and net profit, Selk said.
Temperament was scored on a 1 to 5 scale (1=nonaggressive, docile; 5=very aggressive, excitable). The temperament scoring system was similar to the Florida study.
Exit velocity and pen scores correlated highly, he said. As pen scores increased, so did exit velocity. As pen score and exit velocity increased, health treatments costs and number of days treated increased, while average daily gain and final body weight decreased.
Other studies have shown that excitable temperament can diminish immune responsiveness, with more temperamental calves having a reduced response to vaccination when compared with calm calves, Selk said.
In the Mississippi study, as pen temperament score increased, net profit per head tended to decline, he said.
The heritability of temperament in beef cattle has been estimated to range from 0.36 to 0.45, Selk said. This moderate level of heritability indicates that real progress can be made by selecting against wild cattle.
CATTLE, BEEF RECAP
Fed cattle trading last week was reported at $104 to $105 per cwt on a live basis, up $1 from the previous week. Dressed-basis trading was seen at $164 per cwt, up $1 to $2.
The USDA choice cutout Tuesday was down $0.56 per cwt at $217.16, while select was up $0.57 at $206.99. The choice/select spread narrowed to $10.17 from $11.30 with 98 loads of fabricated product and 36 loads of trimmings and grinds sold into the spot market.
The CME Feeder Cattle Index for the seven days ended Monday was $142.36 per cwt, down $0.25. This compares with Tuesday’s Oct contract settlement of $142.92 per cwt, up $2.00.