1a.Objectives (from AD-416):
Improve the genetic merit of beef cattle and sheep by increasing the accuracy of selection through integration of quantitative genetic and genomic information into genetic evaluation systems.
1b.Approach (from AD-416):
Scientists at the USMARC use large populations of beef cattle and sheep to collect phenotypic data on a broad range of traits affecting efficiency of life-cycle production. Many animals have also been genotyped for thousands of genetic markers. Consequently, extensive volumes of quantitative and genomic data are available to test for associations between genomic variation and economically important traits. Existing experimental data will be analyzed to estimate genetic effects necessary to integrate quantitative and genomic information into genetic evaluation procedures. The expected outcome is increased accuracy of selection leading to more rapid development of populations.
ARS scientists at Clay Center, Nebraska created an easy-care flock of sheep, with one goal being the shedding of fleeces to reduce labor and eliminate costs of shearing. As knowledge of genetic regulation of shedding is scarce, our objective is to estimate heritabilities and genetic correlations involving shedding scores of lambs and mature ewes and thereby improve the accuracy of selection. A total of 5,014 and 3,345 shedding scores were recorded on lambs and ewes, respectively. Preliminary analyses were conducted to determine importance of various discrete and continuous effects (sex of lamb, age and weight of lamb, type of birth and rearing, age of dam, parity, etc.). Complex, multiple-trait models will be fitted to estimate genetic parameters.