API coverage of the 2010 BIF Research Symposium & Annual
Meeting
For more information contact: Shauna Hermel, Angus Productions Inc. editor, at 816-383-5200 or shermel@angusjournal.com
Hair Shedding Rate may
Affect Weaning Weight
by Barb Baylor Anderson
COLUMBIA, Mo. (June 29, 2010) — How quickly cows shed their winter coats in the spring may
have an effect on their calves’ weaning weights. Research led by Trent Smith,
Mississippi State University, with funding from the American Angus Association,
shows a probable link between the two.
“The objectives of this three-year study were
to develop a method to measure hair shedding, determine the variation in
shedding and estimate shedding’s effects on 205-day
weights and body condition scores (BCS),” says Smith. “We observed 532 cows
from 2007-2009 in North Carolina and Mississippi to determine if the perception
is true that cows who do not shed or shed later are not good performers. Cows
seem to perform better when they are in a thermo-neutral zone (TNZ), where heat
stress does not suppress reproduction, milk production and appetite.”
A 1-to-5
scoring system to describe hair shedding was established, and visual
evaluations were done by the same technicians on a monthly basis from March
through July. Data analysis revealed that BCS was not significant, so
researchers focused only on weaning weights. In the adapted score analysis,
Smith found that cows that shed by May had, on average, 589-pound (lb.) calves.
Cows that shed after May had, on average, 565-lb. calves, for about a 24-lb.
difference.
“What we concluded is that cows that shed
later weaned lighter calves, but more data is really needed to confirm the
findings," Smith said. "We believe hair shedding is moderately
heritable, which means it may be possible for producers to select for this.
There is some variation."
Smith
further notes that animals with little or later hair coat shedding might be
good candidates for culling, especially in the Southeast where the evaluations
were made. However, more studies are again needed to determine if the advice
would be the same for other environments. In addition, researchers would like
to consider the effects of prolactin concentrations,
hair regression, changes in the type of diet and
temperatures to assess the rate of shedding.
“Our next steps would be to try the same
observations in different (geographic) areas, as well as see if any other
traits are related to hair shedding,” says Smith. “Over the three years, these
results were repeatable. The same cows tended to shed at about the same time
each year. We would need to find out if that is true in other environments.”
Smith
spoke in Tuesday's Producer Application Committee session at the 2010 Beef
Improvement Federation (BIF) symposium. Themed "Gateway to Profit,"
the 42nd annual research symposium and annual meeting was hosted by BIF June
28-July 1 in Columbia, Mo.
Pictured
above: Trent Smith
Editor’s Note:
This summary was written under contract or by staff of Angus Productions Inc. (API).
To request reprint rights or photo permission contact Shauna Rose Hermel, editor, at 816-383-5270. PowerPoints are posted with permission of the presenter and
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