Research Hair Shedding EPD Launched
Genetic tool will be used to predict heat tolerance and tolerance to fescue toxicosis.
The American Angus AssociationⓇ launches a research expected progeny difference (EPD) for hair shedding Feb. 5, 2020. The research EPD has been in development since 2011 and is now brought to fruition through the collaboration of the American Angus AssociationⓇ, Angus Genetics Inc. (AGI), Mississippi State University, North Carolina State University and the University of Missouri (MU).
Early summer shedding is an indicator for both heat tolerance and tolerance to fescue toxicosis, and it lends discussion to a genetic correlation between a dam’s shedding score and the weaning weights of a calf.
“For producers in heat-stressed areas and producers grazing endophyte-infected (hot) fescue, hair shedding is an evaluation of environmental adaptability and cow performance,” said Harly Durbin, past AGI intern and current MU Ph.D. student. “Cattle that shed their winter coat earlier in the season are less stressed and therefore can put the energy that might have gone to thermoregulation toward growth and taking care of a calf.”
Hair shedding is evaluated on a 1-5 visual appraisal scale, where 5 is a full winter coat, and 1 is completely slick. While there is some variability in shedding patterns between individuals, cattle tend to shed from front to back and top to bottom. Using Angus data, hair shedding has been found to have a moderate heritability of 0.42, falling between that of weaning weight and marbling.
Through the two different projects, 14,465 scores from 8,642 individual cattle have been collected, and more data is encouraged to be submitted to increase the accuracy of predictability of the EPD.
“The selection tool has the ability to help Angus breeders, who are concerned with heat stress, develop registered Angus bulls better suited to work in their commercial customers’ environments,” said Kelli Retallick, AGI genetic service director. “The entire concept of creating tools to select for increases in genetic potential for adaptability in a specific environment is exciting, and as an organization, we will continue to engage in these opportunities as they arise.”
Hair shedding scores should be collected between mid-April and mid-June. Since regional climates exist, it is important to take those measurements when the amount of hair shed varies the most. It is important to note, age has a significant effect on hair shedding. For that reason, cattle must be at least a year of age before hair shedding scores are collected.
Visit Angus.org for more information about the new research EPD.
–American Angus Association
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A pasture or lot with plenty of grass or bedding and windbreak is important when calving in the cold.