Selection Criteria for Beef Cattle for the Future
01 May 1970-Journal of Animal Science (The American Society of Animal Science)-Vol. 30, Iss: 5, pp 706-711
About: This article is published in Journal of Animal Science.The article was published on 1970-05-01. It has received 96 citations till now. The article focuses on the topics: Beef cattle & Selection (genetic algorithm).
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TL;DR: Results based on both experimentation and computer simulation indicate that differences in additive genetic merit of breeds for specific characters can be used in specific crossbreeding systems to synchronize genetic resources with other production resources and to provide for complementarity through terminal sire breeds.
Abstract: Summary The basic objective of beef cattle crossbreeding systems is to optimize simultaneously the use of both nonadditive (heterosis) and additive (breed differences) effects of genes. Experimental results evaluating rotational crossbreeding systems indicate that high levels of heterosis are sustained in successive generations and that the relationship between loss of heterosis and loss of heterozygosity approaches linearity. Major differences among breeds have been demonstrated for most characters that contribute to production efficiency. Results based on both experimentation and computer simulation indicate that differences in additive genetic merit of breeds for specific characters can be used in specific crossbreeding systems to synchronize genetic resources with other production resources and to provide for complementarity through terminal sire breeds. Rotational crossbreeding systems have the advantage of using heterosis in all females and progeny in a self-contained commercial herd; however, fluctuation between generations in additive genetic composition relll~es use of breeds that are generally compatible. This requirement restricts the use that can be made of breed differences to synchronize germ plasm resources with other production resources and eliminates the use of complementarity other than in a combined breed-rotation, terminal-sire system. A static terminal-sire crossbreeding system provides opportunity to synchronize germ plasm resources with other production resources in about 50% of the cow herd, to use maximum (FI) heterosis in about 67% of the calves marketed and to use complementarity in
193 citations
162 citations
TL;DR: Regressed (BLUP) predictions of trait breeding values are useful because they allow appropriate economic weights to be applied as the last step for predicting aggregate breeding values for individuals of different age classes, and they simplify choosing the proportions of selected breeders from each age class that maximize rate of change in aggregate breeding value.
93 citations
TL;DR: Estimation of genetic parameters for scrotal circumference in Nellore cattle found the selection for SC12 would be more effective than selection forSC18 when trying to improve the reproductive traits of the females.
Abstract: The objectives of this work were to estimate of genetic parameters for scrotal circumference (SC) at 12 (SC12, n = 652) and 18 (SC18, n = 607) months of age, age at first calving (AFC, n = 1,582), first (FCD, n = 1,582) and second (SCD, n = 644) calving dates and first calving interval (FCI, n = 644) in Nellore cattle. Parameters were estimated using REML methodology, with animal models and considering the relations among 15,648 animals. Heritability estimates from univariate analyses were .24±.10, .31±.10, .01±.03, .11±.05, .07±.08 and .10±.10, respectively, for SC12, SC18, AFC, FCD, SCD and FCI. These values were close to the estimates from bivariate analyses, except for the analysis including both SC (heritability estimates of .61 and .68, respectively, for SC12 and SC18). Genetic correlation estimates between SC12 and, respectively, AFC, FCD, SCD and FCI were ¾1.00, -.08, -.71, and -.37. In the same order, genetic correlation between SC18 and female reproductive traits were ¾1.00, .21, -.35 and -.44. The selection for SC12 would be more effective than selection for SC18 when trying to improve the reproductive traits of the females.
66 citations
TL;DR: Investigation of the effect of different breeds and breed crosses on age, BW, price, and market value of purebred and crossbred calves sold for veal and beef production found sex, age, and breed were the most relevant sources of variation for BW, whereas breed and sexwere the most important sources of variations for AC, PR, and MV.
Abstract: The aim of this study was to investigate the effect of different breeds and breed crosses on age (AC, d), BW (kg), price (PR, $/kg), and market value (MV, $/calf) of purebred and crossbred calves sold for veal and beef production. The Kovieh wholesale cattle organization (Bolzano, Italy) grouped calves from sev- eral dairy herds located in the Trentino-Sudtirol region in Italy and sold them by public auctions. Data on AC, BW, PR, and MV from 96,458 calves were recorded from January 2003 to December 2007 and consisted of 4 pure breeds (2 dairy, Brown Swiss (BS) and Holstein- Friesian (HF); and 2 dual-purpose, Simmental (SI) and Alpine Grey (AG)), and 8 crossbreds by crosses of Limousin (LI) and Belgian Blue (BB) with the 4 dam breeds. Least squares means for AC, BW, PR, and MV were calculated for breeds and breed crosses with a model that included fixed effects of herd of birth, age (except for AC), sex, and breed of the calf, year and season of auction, and interactions between the main effects. The coefficients of determination of the mod- els were 0.41, 0.51, 0.84, and 0.82 for AC, BW, PR, and MV, respectively. Sex, age, and breed were the most relevant sources of variation for BW (P < 0.001), whereas breed and sex were the most important sources of variation for AC, PR, and MV (P < 0.001). Also, PR and MV were significantly influenced (P < 0.01) by all the effects included in the model, except for sea- son × age interaction in the case of MV. Market value of male was greater (P < 0.001) than that of female calves, with the exception of BS (−$28.76/calf) and HF (−$20.70/calf) purebred males. Dual-purpose pure- bred calves presented greater (P < 0.001) PR and MV than dairy purebreds (MV of $426.97/calf and $307.96/ calf for SI and AG, and $256.24/calf and $275.65/calf for BS and HF, respectively). Calves from SI and AG dams had greater (P < 0.001) BW, PR, and MV than calves from BS and HF dams. Calves from SI cows had greater (P < 0.001) BW, PR, and MV than calves from AG cows. Crossbreeding with beef bulls increased (P < 0.001) BW, PR, and MV of calves from dairy and dual- purpose dams. Crossbreeding with BB bulls increased PR (+$2.58 ± 0.04/kg; P < 0.001) and MV (+$190.84 ± 3.62/calf; P < 0.001) of calves much more than LI. The use of beef bull semen on dairy herds resulted in an economic revenue from selling crossbred calves.
63 citations
Cites background from "Selection Criteria for Beef Cattle ..."
...Results highlighted that breed complementarity (Cartwright, 1970) occurred and the use of crossbreeding on cows not used to breed replacements in dairy herds can result in greater economic revenue from selling crossbred calves....
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...One reason for crossbreeding is to combine favorable attributes of 2 or more breeds that are genetically different from each other but have complementary qualities (Cartwright, 1970)....
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