Cattle Shedding Hair Can Impact Performance Based On MU Extension Evaluation

MT. VERNON, MO.
   Temperatures in southwest Missouri are already in the upper 80’s and that along with elevated humidity can bring discomfort to cattle that are still wearing their winter coats.
   The situation worsens if the cattle are grazing toxic, endophyte-infected fescue which can further retard heat dissipation by the cattle according to Eldon Cole, livestock specialist, University of Missouri Extension.
   “An area of interest that could improve the comfort of the cattle is to have them shed their hair more quickly in the spring. One management tip for owners of cattle on ‘hot’ fescue is to select replacements, both male and female, that shed their hair early,” said Cole.
   Researchers say hair shedding is about .35 heritable which is a moderate level and should respond to selection over time within a breed.
   “Certain breeds that are more heat tolerant do slick off sooner and may bear consideration in selecting breeds for a cross,” said Cole.
   OZARKS RESEARCH
   University of Missouri Extension specialists have evaluated both cows and yearling stocker cattle at University of Missouri’s Southwest Research Center in Mt. Vernon. This evaluation involved scoring the cattle at different times of the spring and summer for shedding.
   The numerical scoring system was a one for “slick as a mole,” two if well shed off except for patches of long hair on lower parts, three if they had started shedding along their topline, but had over one-half of their body unshed, and four if the animals basically had their full winter coat.
   “There was a trend for cattle with more hair retention in the summer to show poorer performance in our limited trials,” said Cole.
   Since initial MU Extension studies done in the mid-90’s, other universities like Mississippi State, have done shedding trials using a one to five scoring system. In those evaluations, a three animal was one-half shed, the four was about 25 percent shed and five still had a full winter coat.
   Data from Mississippi State’s work on fall calving cows showed that cows shed off in March weaned calves weighing 597 lbs. while those not shedding until July weaned a 551 pound average during the three-year study. The May shedders even showed a 36 pound weaning weight advantage over the Julys.
   “Not only can weaning weights be affected, we see lowered reproduction rates blamed on elevated body temperatures which may trace back to long hair coats. Part of this is attributable to the fescue problem,” said Cole.
   In southwest Missouri, mid-May is a good time to evaluate cattle for shedding ability. Cole says producers can use either the 1 to 4 or 1 to 5 systems or develop a method of their own.
   “Shedding appears to not only be heritable but is repeatable from year to year. Check your own herd to see if there’s a trend for late shedders to be low performers,” said Cole. Δ