Thursday, March 30, 2006

Genetic Tests Beef Up Cattle Breeding

Geneticists with the Agricultural Research Service (ARS) in Clay Center, Neb., are improving traditional cattle breeding methods with marker-assisted selection, a process that incorporates DNA tests into traditional genetic evaluation systems.

Traditionally, breeders have used visual appraisal to estimate cows’ genetic merit. By carefully recording the characteristics of herd members and their descendents, animal breeders can calculate an animal’s Expected Progeny Difference, or EPD.

This is a figure estimating the average performance of specific traits for an individual’s offspring.More recently, geneticists have developed DNA tests associated with important traits in cattle. These tests might someday be incorporated into the established selection process.

According to ARS geneticist R. Mark Thallman, incorporating DNA tests in breeders’ calculations could improve the accuracy of their EPDs and place the appropriate degree of emphasis on the DNA tests.

With geneticist Mark F. Allan, he is testing that theory, using a herd selected for producing twins as a prototypical population. Previous research located three genetic regions linked to the twinning trait.

This information has been incorporated into the scientists’ calculations since 1998, enabling them to make more accurate genetic predictions, or "marker-adjusted EPDs."

The twinning experiment is simply one example of marker-assisted selection’s potential. In similar work, researchers from Cornell University, ARS and Iowa State University incorporated DNA test results into a genetic evaluation of Simmental cattle for tenderness, allowing Simmental breeders to use marker-assisted selection for tenderness.In the future the technique could be used to improve other desirable traits, such as efficiency, fertility and growth rate.

Marker-assisted selection will allow breeders to increase the speed and accuracy of traditional assessment methods, but its advantages extend beyond the seedstock industry.

Commercial cattle producers would be able to purchase bulls with superior genetics. The desirable characteristics in the livestock would ultimately translate into better products for consumers.

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AGRI-INFO/MARCH 30, 2006


TITLE: GENETIC TESTS BEEF UP CATTLE BREEDING

ALAM BA NINYO NA NATUKLASAN NG MGA EKSPERTO ANG GENETIC TEST NA NAGLALAYONG MAPAHUSAY ANG TRADISYUNAL NA CATTLE BREEDING METHODS SA PAMAMAGITAN NG MARKER-ASSISTED SELECTION - ISANG PROSESO SA KUMBINASYON NG DNA TEST SA TRADITIONAL GENETIC EVALUATION SYSTEMS.

SA TRADISYUNAL NA PAMAMARAAN, ANG MGA BREEDER AY GUMAGAMIT NG VISUAL APPRAISAL PARA MATAYA ANG GENETIC MERIT NG GATASANG BAKA.

SA PAMAMAGITAN NG MAINGAT NA PAGTATALA SA CHARACTERISTICS NG MGA NASA KAWAN AT KANILANG DESCENDANTS, MAAARING MA-CALCULATE NG ANIMAL BREEDERS ANG EXPECTED PROGENCY DIFFERENCE O EDP NG ALAGANG HAYOP.

KAMAKAILAN LAMANG, NAGAWANG MA-DEVELOP NG MGA GENETICIST ANG DNA TESTS NA MAY KAUGNAYAN SA MAHAHALAGANG KATANGIAN NG BAKA AT ANG TEST NA ITO AY MAAARING MAISAMA SA SUBOK NANG SELECTION PROCESS.

AYON KAY GENETICIST R. MARK THALLIMAN, ANG PAGSASAMA NG DNA TEST SA BREEDERS' CALCULATIONS AY MAKAPAGPAPAGANDA SA ACCURACY NG KANILANG EPDs AT MAILAGAY ANG ANGKOP NA ANTAS NG PAGSUSURI SA DNA TESTS.

SA MGA NAKALIPAS NA PANANALIKSIK, NATUKOY ANG TATLONG GENETIC REGION NA MAY KAUGNAYAN SA TWINNING TRAIT NG BAKA. ANG IMPORMASYON NA ITO AY ISINAMA SA KALKULASYON NG MGA SIYENTISTA MULA PA NOONG 1998, PARA SA MAS TUMPAK NA GENETIC PREDICTIONS.

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