Heterose sobre os pesos de bovinos Canchim e Aberdeen Angus e de seus cruzamentos recíprocos

Abstract

RESUMO -O trabalho foi conduzido para estimar a heterose sobre os pesos ao nascimento (PNT), à desmama (P210) e ao ano (P365) e sobre os ganhos de pesos médios diários do nascimento à desmama (G210) e da desmama ao ano (G365) nas quatro primeiras gerações do sistema de cruzamentos alternados entre as raças Canchim (C) e Aberdeen Angus (A). Os dados de 1.147 bezerros nascidos de 1981 a 1998 foram analisados pelo método dos mínimos quadrados, ajustando-se um modelo linear que incluiu os efeitos linear e quadrático da idade da mãe do bezerro e os efeitos fixos de sexo, grupo genético, mês e ano de nascimento do bezerro. Estimativas de heterose e de outras diferenças genéticas foram estimadas por contrastes entre médias e testadas pelo teste t. O contraste "C-A" foi positivo e significativo (P<0,001) para as cinco características. O contraste F 1 CA-F 1 AC teve sinal negativo e foi altamente significativo (P<0,001) para P210 e G210 e significativo (P<0,05) para P365. A geração F 1 exibiu heterose de 4,8% para P210 e de 4,9% para G210. A heterose materna foi de 3,7%, 5,8%, 6,3% e 20,4%, respectivamente, para P210, G210, P365 e G365. A heterose média das terceira e quarta gerações do cruzamento alternado entre C e A foi de 4,6% para P210, 5,3% para G210 e de 3,5% para P365.Termos para indexação: gado de corte, cruzamentos alternados, diferenças genéticas. HETEROSIS UPON WEIGHTS IN CANCHIM AND ABERDEEN ANGUS CALVES AND IN THEIR RECIPROCAL CROSSESABSTRACT -The study was conducted to estimate heterosis upon birth weight (PNT), weaning weight (P210), yearling weight (P365) and daily weight gain from birth to weaning (G210) and from weaning to one year of age (G365) in the first, second, third and fourth generations of a rotational crossbreeding system between Canchim (C) and Aberdeen Angus (A). Data from 1,147 calves born from 1981 to 1998 were analyzed by least squares procedures fitting a linear model that included the linear and the quadratic effects of age of the dam of the calf plus the fixed effects of sex, genetic group, month and year of birth of calf. Estimates of heterosis and of other genetic differences were obtained by linear contrasts of appropriate means and tested by the t test. The contrast C-A was positive and significant (P<0.001) for all five traits. The contrast F 1 CA-F 1 AC was negative and highly significant (P<0.001) for P210 and for G210 and significant (P<0.05) for P365. The F 1 generation exhibited heterosis of 4.8% for P210 and of 4.9% for G210. Maternal heterosis was 3.7%, 5.8%, 6.3% and 20.4%, respectively, for P210, G210, P365 and G365. The heterosis estimated for the mean of the third and fourth generations of the rotational crossbreeding system between C and A was 4.6% for P210, 5.3% for G210 and 3.5% for P365.

Genetic and Genomic Characterization of a New Beef Cattle Composite Breed (Purunã) Developed for Production in Pasture-Based Systems

“…This was performed to improve key traits of interest and exploit the complementarity among the breeds ( Otto et al, 2021 ), especially for production in pasture-based systems. The background research to generate the Purunã breed started at the Agronomic Institute of Paraná (IAPAR; Ponta Grossa, Paraná, Brazil) at the beginning of the 1980s, when IAPAR researchers estimated the heterosis in the crossbred progenies of Charolais x Caracu and Angus x Canchim ( Perotto et al, 2000a ; Perotto et al, 2000b ). Almost 15 years later, the first results were obtained from this experiment, where the heterosis retained from those crosses resulted in higher hot carcass weight, hot carcass yield, rib-eye area, better carcass conformation from Charolais x Caracu ( Perotto et al, 2000b ), and higher average weight daily gain in different ages with the crosses of Angus x Canchim ( Perotto et al, 2000a ).…”

Crossbreeding effects on growth and efficiency in beef cow–calf systems: evaluation of Angus, Caracu, Hereford and Nelore breed direct, maternal and heterosis effects

“…The main objective of the use of the genetic resources is to exploit genetic differences between breeds, heterosis, and complementarity to improve the performance of animals raised in different environmental conditions ( Perotto et al, 2000 ; Prayaga, 2003 ). Therefore, we measured cow performance and estimated EI to identify crosses that are characterized by a favorable balance of outputs and inputs; an essential feature of successful crossbreeding systems ( Trematore et al, 1998 ).…”

Efeitos ambientais e genéticos sobre peso, perímetro escrotal e escores de avaliação visual à desmama em bovinos da raça Canchim

“…Vários trabalhos da literatura trazem relatos sobre a influência de fatores ambientais e heteróticos (Alencar et al, 1993;Mascioli et al, 1996;Trematore et al, 1998;Perotto et al, 2000;Dal-Farra et al, 2002;Jorge Júnior et al, 2004) sobre escores visuais de conformação, precocidade e musculosidade e, ou, características de crescimento e de perímetro escrotal, mas há carência de estudos sobre os escores de conformação frigorífica, de qualidade do pelame e de umbigo.…”