POCATELLO, Idaho — Idaho State University and Montana State University researchers believe a common blood test for evaluating performance of elite athletes could help the cattle industry better assess the dispositions of livestock.
The project, conducted in 2012 at Nebraska’s Chappell feedlot, utilized readily available, low-cost sport performance meters that instantly estimate lactate levels from a single drop of blood. Their findings have been published online by Meat Science and will appear in the journal’s May 2015 print publication.
Blood lactate accumulates when exercise, or stress, triggers anaerobic metabolism — when oxygen delivery to tissue is insufficient to meet normal metabolic demands. In humans, a lower lactate reading following strenuous exercise indicates an athlete is in excellent shape and well equipped to handle the stress of competition.
Michael Meyers, an associate professor of sports science at ISU, reasoned the same, simple test could measure stress in steers, enabling the industry to breed animals with the most docile dispositions, evaluate individual animals and monitor how handling and facility designs affect cattle stress.
Meyers, who also has a background in animal sciences, explained other studies have shown stress reduces weight gain in livestock and may even decrease tenderness.
The industry standard for evaluating animal stress entails recording an animal’s speed at moving through a chute and also assigning a score based on its behavior. In theory, slower-moving, less-irritable livestock have a calmer disposition, which should correlate with low stress and tender meat.
“Some (cattle) just freeze in the chute and don’t move at all. We wanted to move away from subjective scoring with human error in it to some bio-marker,” said Meyers, who is also a visiting research faculty member with MSU’s Department of Animal and Range Sciences.
Meyers is optimistic his lactate test will eventually become widely adopted as the industry seeks to stay on the cutting edge of animal welfare technology.
Jane Ann Boles, an associate professor of meat sciences at MSU and the lead researcher on the lactate project, found a correlation between lactate levels and chute score and velocity. Cattle in the experiment were also evaluated postmortem for tenderness. Cattle with fast chute scores tended to yield tougher meat.
Boles said cattle with low lactate levels generally yielded tender meat, and animals with medium lactate were tougher. She was surprised, however, to find animals with the highest lactate levels were also tender — she hypothesizes they’re accustomed to high lactate levels and predisposed to quickly rid their systems of it postmortem. She advises high lactate animals should, nonetheless, be screened out due to other problems associated with stress.
Boles said further study with larger herds will be necessary to advise livestock operators on how to interpret lactate readings. But she believes lactate testing may help reduce variation in meat quality. The research was funded by the Bair Ranch Foundation and the Montana Experiment Station.
In 2014, Boles started an additional, ongoing study evaluating other bio-markers such as blood glucose, fatty acids and the hormone cortisol, released in response to stress.
She’ll also evaluate bio-markers, chute scores and chute velocity used in combinations.