Author
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Cundiff, Larry |
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Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only Publication Acceptance Date: 12/1/2004 Publication Date: 3/1/2005 Citation: Cundiff, L.V. 2005. Performance of tropically adapted breeds in a temperate environment: calving, growth, reproduction and maternal traits [abstract]. American Society of Animal Science Southern Section Meeting 83(2):28. Interpretive Summary: No interpretive summary is required. Technical Abstract: Results will be reviewed from an analysis of data for 8,484 calves produced in the Germplasm Evaluation (GPE) Program at MARC. Although the analysis involved progeny of 27 sire breeds, this report will focus on comparisons among progeny sired by tropically adapted breeds including Brahman (Bh) and Sahiwal (Sw) in Cycle III (1973-1974); Nellore (Ne) and Longhorn (Lh) in Cycle IV (1986-1990); Bh, Boran (Bo), and Tuli (Tu) in Cycle V (1992-1994); and Beefmaster (Bf), Brangus (Ba), Bonsmara (Bs), and Romosinuano (Ro) in Cycle VIII (2001-2002). Hereford (H) and Angus (A) sires provided ties for pooling data over cycles for least squares analyses using a model that included random effects for sire in breed, and fixed effects for sire breed, dam breed, sex, cow age, birth year, and sire breed-dam breed interaction. Data obtained on three-way cross progeny by Red Poll (Cycle IV and V) sires for unassisted calvings, birth weight, and weaning weight were similarly analyzed. Bos indicus sired progeny had heavier birth weights and required more assistance at calving than progeny of other breeds; however, birth weights were significantly heavier in H and A sired females than in those by other breeds, and N, Bh, Sw, and Lh females required less assistance at calving than those by other breeds. Growth rates, primarily during summer months, to weaning ages were greater for Bh and Ne sired progeny than in Bo, Sw, A, and H sired progeny, which were in turn greater than in Tu or Lh sired progeny. However, weights at yearling ages (400 or 550 d), affected primarily by growth rate during winter months, were heavier for progeny of Bf, Ba, A, and H sires than N, Bo, and Bh sires which were in turn heavier than for progeny of Ro, Tu, or Lh sires. Age at puberty was significantly younger for Lh, Tu, Ba, Bf than for Ne and Bh sired females, intermediate for Ro and Bo which were not significantly different from any other breed except A and H which were youngest. Progeny of Bh and Ne sired females were heavier at weaning than those of other tropically adapted breeds and A and H sires. |
