Hereford Assoc. releases new udder EPDs
December 19, 2014
With the release of the spring 2015 Pan-American Cattle Evaluation (PACE), the American Hereford Association (AHA) has released two new expected progeny differences (EPDs) for udder quality.
The two traits — udder suspension (UDDR) and teat size (TEAT) — were first released on the web. You can find them by going to Hereford.org and clicking on "EPD Search." They are located in the EPD trait box positioned right after maternal cow weight (MCW). This first release will be the trait by itself with no correlations to other traits, and there will not be a genomic impact with genomic enhanced-expected progeny differences (GE-EPDs).
According to Jack Ward, AHA chief operating officer and director of breed improvement, there were around 200,000 udder observations included in the first evaluation, and the heritability for both UDDR and TEAT is about .34, which makes this trait fairly highly heritable, so genetic progress can be made rather quickly.
"The correlation between the two scores and one is .72, so it makes all udder scores useful in this evaluation," Ward says. "This EPD can be used the same as other EPDs and will allow you to compare animals and, most importantly, has the potential to change udder quality between sire groups."
In July 2008 the Beef Improvement Federation (BIF) adopted a two-score system for evaluating udders. The AHA Board of Directors followed suit and adopted the same system during its August 2008 meeting. See the "Udder Scoring Fact Sheet" posted in the Hereford.org "Education Center."
Scores of 1 to 9 are used for both traits with 9 being more close to ideal. "This scoring system is not concerned with milk flow or production; those will be measured with the weaning weight (WW) and milk and growth (M&G) EPDs," Ward explains. "All we are looking at with this trait is the type of udder and teat."
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Scores range from 9 (very tight) to 1 (very pendulous) and represent assessments of udder support. Weak udder suspension results in pendulous udders that make it difficult for a calf to nurse.
Weak suspension in the udder indicates a lack of support in the ligament that ties the udder to the cow's body wall. Over time, weakness in this ligament will allow the udder to hang down too far from the body and may subject the udder to serious problems and increased potential for injury.
UDDR EPDs are reported on the scoring scale. Differences in sire EPDs predict the difference expected in the sires' daughters' udder characteristics when managed in the same environment.
For example, if sire A has a UDDR EPD of 0.4, and sire B has a UDDR EPD of -0.1, the difference in the values is 0.5, or one-half of a score. If daughters of sires A and B are raised and managed in the same environment, you would expect half a score better udder suspension in daughters of sire A, compared to sire B.
Scores range from 9 (very small) to 1 (very large, balloon shaped) and are subjective assessments of the teat length and circumference. Oversized teats are difficult for newborn calves to nurse, and the calf may not receive adequate colostrum. This could lead to a higher incidence of scours or decreased immunity levels in the newborn calf.
TEAT EPDs are reported on the scoring scale. Differences in sire EPDs predict the difference expected in the sires' daughters' udder characteristics when managed in the same environment.
For example, if sire A has a teat size EPD of 0.4, and sire B has a teat size EPD of -0.1, the difference in the values is 0.5, or one-half of a score. If daughters of sires A and B are raised and managed in the same environment, you would expect half a score smaller teat size in daughters of sire A, compared to sire B.
Just like with the scoring system, the higher the EPD the better for both traits.
"These are important traits to analyze because commercial producers demand genetics that are problem-free," Ward says. "The loss of time, longevity and calf performance due to a poor quality udder cannot be tolerated."
With the release of spring 2015 EPDs, the updated Trends, Traits and Distributions report is now also available online at Hereford.org.
"The Association's role is to give our members tools to make improvement in beef production," Ward adds. "Udder EPDs are the next phase in breed improvement strategies that will allow our members to continue to improve the genetics they produce."
For more information about AHA's suite of EPDs or breed improvement programs, contact Jack Ward at 816-842-3757 or firstname.lastname@example.org.
–American Hereford Association