Criteria for Culling Cattle- a new approach

A New Culling Criteria: Hair Coat Shedding

Guest Post:

By Eileen A. Coite, Wayne County

Compiled from: Differences in hair coat shedding and effects on calf weaning weight and BCS among Angus dams, K.A. Gray, et al.

It’s always exciting when we learn of new university research to pass on to you, the producer. After all, that is a big part of what Extension does. So, when I learned of beef cattle research being conducted in North Carolina and Mississippi that could impact management and decisions of cattle producers, I was excited to share the news. At our annual livestock agent training held each August, agents are given time to interact with one another and NCSU specialists, in an effort to gain the most up to date knowledge, practice skills, and share ideas. This year, amongst many presentations and workshops, we learned of collaborated research being conducted by the Department of Animal Science at NC State University and the Department of Animal and Dairy Sciences at Mississippi State University with regard to the impact hair coat shedding has on calf weaning weight and body condition score of Angus cattle.

Angus producers have long been interested in finding ways to help their cattle get through the hot summer with less stress and complications from the heat, particularly because of their black hair coat. Humidity in the southeast added to the hot summer temperatures creates risks of heat related challenges for all livestock, but particularly cattle with dark, thick coats. For these reasons, researchers at NCSU and MSU teamed up to learn how much variation in shedding exists among purebred Angus cows, and the effects of this shedding on weaning weight of their calves and the cow’s body condition score. Researchers of this project adapted a scoring system to evaluate a cow’s shedding progress, referred to as a hair shedding score.

So what did they find? Through evaluating over 500 Angus cows in four different locations of MS and NC, cattle were grouped in five categories of shedding, ranging from a full winter coat to a slick, short summer coat. All cows weaned a calf at approximately six months of age and weaning weights were recorded and submitted to the American Angus Association. Data was analyzed to show how early cattle began to shed, an indication to how well adapted they were to the heat of the southeast. The study found that there was a definite correlation between speed of shedding and weaning weights, showing cows with slower shedding to raise lighter calves at weaning. The study states that there are many possible reasons why this relationship is present. One possible reason there is a connection between weaning weight and hair coat shedding is that prolactin levels in cows were affected. Prolactin is a hormone present in cows that affects lactation, but also has effects on hair loss. The study brought about possible conclusions that higher prolactin levels could influence hair shedding as well as milk production, leading into heavier calves at weaning.

The study concluded that even though more research is needed to fully understand this correlation, a conclusion was made that producers could lessen heat stress in their herds and improve weaning weights by culling cows that are slow or poor at shedding. Scoring cattle for shedding in late May or early summer, and removing cows from the herd that receive scores that reveal little to no shedding should increase herd productivity by increasing weaning weights of calves produced.