Resumen de Performance evaluation of Canchim calves raised on pasture in Parana state, Brasil
Júlio César de Souza, Elisangela Borsoi Pereira, Daniel Perotto, José Luiz Moletta, Ana Paula Miyagiç, José Antonio de Freitas
The objective of the present work was to evaluate the effects of environment upon birth and weaning weight (adjusted to 205 days of age, PN and PD respectively) of Canchim calves raised on pasture. Data of 2,719 animals born from 1977 to 1996, at Fazenda Modelo Experimental Farm of IAPAR, in Ponta Grossa-Paraná-Brazil, were used. Analyses were performed through GLM procedure (SAS 2001). The statistical model included fixed effects of breed composition, sex and year of birth of calf and random effects of sire and error. Except for breed composition (P<0.55), all other sources of variation considered in the model were significant (P<0.0001). Least squares means for PN and PD were 33.98 ± 0.38 kg and 145.13 ± 2.45 kg, respectively. Calves born in March weighed 38.07 ± 1.28; while those born in June weighed 31.48 ± 0.44. For weaning weight, animals born in July were heavier, with average weaning weight of 158.00 ± 2.3 kg in contrast to those born in January (123.82 ± 4.51 kg). The effect of the different sources of variation indicates that the establishment of a breeding season during certain months can result in calves heavier at weaning. The heritability estimates suggest that phenotypic characteristic of individuals are a good indicator of the genotype. The estimates for direct heritability (h²A) were 0.29 ± 0.02 and 0.21 ± 0.2 respectively for PN and PD, indicating the existence genetic variation for both characteristics. (Portuguese)
