|Van Vleck, Lloyd|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: November 17, 1997
Publication Date: N/A
Technical Abstract: Records of progeny of sires of 12 breeds mated to Angus (2413) progeny) Hereford (1875), and MARC-III (603) composite (3 breeds of sire) dams at the US Meat Animal Research Center provide estimates of breed of sire differences that are adjusted for genetic level of bulls used at MARC to calculate across-breed adjustment factors to add to within-breed EPD. For birth weight, estimable differences among sire breeds were essentially the same for the breeds of dams. For weaning weight, differences among sire breeds were not significantly different for the dam breeds. The male-female difference at weaning was significantly different for MARC-III from that for Hereford or Angus dams. For yearling weight, breed of sire differences were generally larger for Hereford than for Angus dams. Hereford-Brahman sire breed difference was significantly larger for MARC-III than for Angus dams. Regression on day of birth was positive for MARC-III but negative for rHereford and Angus dams. Male-female difference was larger for Hereford (significant) and for MARC-III than for Angus dams. Genetic correlations between expression of a sire's genotype were from .86 to 1.00 in Angus and Hereford dams, from .66 to .88 in Hereford and MARC-III dams and from .65 to .83 in Angus and MARC-III dams with smallest correlations for weaning weight. Phenotypic variances, although not coefficients of variation, were greatest for progeny of MARC-III dams. Conclusions are that 1) estimates of differences for sire breeds for birth and weaning weight do not depend on breed of dam, 2) regression on day of birth should be within dam breed, 3) breed of dam by sex of calf combination should be considered in the analysis model, and 4) expression of sire superiority may be somewhat different in progeny of MARC-III and Hereford or Angus dams.