New stats could help producers pick the best bulls for high altitudes
When choosing which bulls to mate with cows, cattle producers have to consider genetics. Genetic predictions can help producers select bulls that will pass useful traits to offspring in their herds. These predictions, however, are no guarantee of actual performance. Outside factors can affect how genes are expressed in each animal.
In a recent paper for the Journal of Animal Science, researchers from the University of Georgia and the Institute of Genetics and Animal Breeding in Magdalenka, Poland investigated the effect of altitude on Angus cattle performance. They were trying to see if expression of certain traits was significantly different between low and high altitudes.
The scientists focused on a major factor that affects performance of cattle: brisket disease. This disease, triggered by high blood pressure, causes fluid to build up in the chest and lower body and occurs with greater prevalence at higher altitudes. According to the authors of this study, brisket disease is a major factor preventing cattle living at higher altitudes from performing as well as cattle from lower altitudes.
Using data from the American Angus Association, the researchers analyzed traits for cattle growth and health. They looked at cattle weight at weaning, weight gain after weaning, and whether cattle survived to be a year old. They found that the effects of weaning weight and postweaning gain are not highly correlated across high and low altitudes, indicating that measurements of these traits taken at different altitudes should be considered separate traits. This would mean that sires would be evaluated differently based on the altitude at which they were intended to be used.
“Different sets of genes are required for successful performance in different environments,” said Marek Łukaszewicz, professor at the Institute of Genetics and Animal Breeding and coauthor of the study. “Some of those genes are common to many environments and some are not…with the computing capacity of today, it should not be a problem to introduce a few more traits to the national evaluations.”
Because altitude is not traditionally reported in breeding statistics, the researchers suggested that producers make selection decisions based on a bull’s ability to survive its first year. A bull with a high score for survivability could thrive at low altitudes and make do at high altitudes. After considering survivability, producers could then consider weight gain scores to pick the best bull.
By considering survivability, producers can also select bulls less likely to get brisket disease.
“Direct observations on brisket disease would be best but are unavailable,” said Ignacy Misztal, a coauthor and professor at the University of Georgia. “Comparison of survival and [postweaning gain] at high and low altitudes allows for indirect measure of adaptation to high altitude.”
This study was titled “Genotype by environment interaction for growth due to altitude in United States Angus cattle.” It can be accessed at the journalofanimalscience.org.
ASAS Scientific Communications Associate
MadelineMS@asas.org / 217-689-2435