Fernando Brito Lopes

Tendência genética para características relacionadas à velocidade de crescimento em bovinos Nelore da região norte do Brasil

The objective was to estimate the (co) variance, genetic parameters and trends for the characteristics, days to gain 160 kg (D160) in the pre-weaning phase, and days to gain 240 kg (D240) in the post-weaning phase, in Nellore cattle, grown in Northern Brazil. Records analyzed were of animals raised on pasture in northern Brazil, provided by the Brazilian Association of Zebu Breeders - ABCZ, and collected from 1997 to 2007. Contemporary groups (herd, year, birth season and gender) were used as a fixed effects model, and age at calving as a covariant. Estimates of (co) variance were obtained using the MTDFREML software. The averages observed for D160 and D240 were 235 ± 46 days and 578 ± 171 days respectively. Estimates of heritability for D160, due to the additive genetic and maternal effect, were 0.27 ± 0.03 and 0.35 ± 0.04, respectively. For D240, the heritability for the additive genetic effect was 0.28 ± 0.03. This indicates that selection for any of the characteristics will result in genetic progress. Potential genetic gains due to the additive genetic effect, were 1.02 and 3.17 days per year for D160 and D240 respectively. This corresponds to 0.43 and 0.55% of the average of days to gain 160 kg (pre-weaning) and 240 kg (post-weaning) respectively. Although weight is currently used as the selection criteria, the genetic trends for D160 and D240 indicated the existence of genetic progress when using these characteristics as the selection criteria.

Caracterização fenotípica de ovelhas dos humedales de ite, sul do peru: dados preliminares

Sheep farming is an important socioeconomic activity in Peru, being one of the main sources of income for many rural families. The objective of the present study was to characterize the phenotype of adult ewes, from local flocks farmed in the Ite Wetlands, southern coast of Peru. These animals were reared in a semi extensive system, on native pastures. Thirteen morphometric traits were measured and analyzed using MEANS, CORR, GLM, DISCRIM and CLUSTER procedures of the statistical program SAS. Three morphologic traits were also registered and three zoometric indices calculated. The results indicated that these ewes are smaller than specialized breeds, but had tendency for meat production and different body sizes, showing variability of biotypes between flocks, according to the management, geographical location and apparent racial miscegenation.