COLUMBIA, Mo. — On a hot, early summer day in 1993, Dr. Rich Crawford and I were weighing steers at the University of Missouri’s Southwest Research Center, Mt. Vernon. The research trial involved mineral supplements for yearling steers grazing “hot” Kentucky 31 fescue. Rich was a research associate at the time.
We visited about how rough the haircoats of many of the steers were. In addition, some steers were showing other typical “hot” fescue signs such as high respiration rates, muddy hair coats and slobbering. As we weighed the cattle, we decided to devise a scoring system to track the performance of the hairy steers compared to the less hairy ones.
The “spur-of-the-moment” system was to call the slick, well-shed steers as 1’s. Some shedding but definitely not slick, were given a 2 score. The 3 steers showed very little hair loss, but some. Cattle that didn’t appear to have shed a hair were called 4’s. After that trial we’ve tried to incorporate hair scores into most of the fescue grazing trials at the research center. Now, 27 years later, it’s exciting to see the beef industry taking hair shedding to a whole new level. As exciting use of hair scoring is the release in February, by the American Angus Association of research hair shedding expected progeny difference (EPD) on 270 bulls. This research began in 2011 and is a joint effort of the Angus Association, Angus Genetics Inc., Mississippi State University, North Carolina State University and the University of Missouri led by Dr. Jared Decker.
This research effort has involved 14,465 scores from 8.642 individual cattle. The research data is still being collected. The research is not specific to how cattle adapt to toxic fescue. The bigger picture is what hair coat difference does for cattle’s tolerance to heat.
At this point, the Angus data show hair shedding has a moderate heritability of 0.42. Thus, you can use visual scoring to select for early shedding. The optimum time to score your cattle is from mid-April to mid-June. The recent research uses a 1 to 5 hair score system instead of the rather vague 1993, 1 to 4 system.
The new system is as follows: 1’s are completely shed from front to back, top to bottom; 2’s are 75% shed with the only remaining hair being along the underline; 3’s are 50% shed with the slick area around the head, neck and along the topline; 4’s are 25% shed, only in the fore quarters; 5’s show no signs of shedding and basically have their full winter coats.
As you work your cows this spring, designate one or two persons to enter a shedding score, 1 to 5, with no half-scores. Only score cattle that are one year and older. Try to score your cattle within a 7 days time frame if they’re to be compared to one another.
The MU doctoral student on the study, Harly Durbin, says the research is not just a way to track animals who shed easily and early but it is a way to evaluate their environmental adaptability and cow performance. If you’ve used considerable Angus genetics, you’ll find the EPDs on the 270 bulls interesting. The list contains bulls born from 1978 to 2014. The research report average EPD was +0.53. A lower number indicates an earlier shedder. The accuracy of the list is only 0.40. The range in EPD’s was -0.14 (early shedder) to +1.17 (slow shedding).,
If you feel slow shedding is affecting your herd’s performance you might seek more information from your University of Missouri Extension field specialist in livestock.
— Eldon Cole, University of Missouri Extension
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