Parâmetros genéticos para a produção de leite em caprinos das raças Saanen e Alpina

Abstract

*Resumo -Objetivou-se com este trabalho estimar parâmetros genéticos para a produção de leite acumulada até os 305 dias (P305) de cabras das raças Saanen e Alpina. Foram utilizadas as duas primeiras parições de cabras pertencentes a rebanhos participantes do programa de controle produtivo e reprodutivo de caprinos (PROCAPRI) da UNESP-FCAV-Jaboticabal-SP. A P305 foi analisada por meio de modelos de repetibilidade e bicaracterísticas. Para verificar a influência dos efeitos fixos sobre a característica analisada foram realizadas análises preliminares, pelo método de quadrados mínimos. Os componentes de covariâncias foram estimados pelo método da máxima verossimilhança restrita (REML), utilizando o programa Wombat. A duração da lactação, a idade da cabra ao parto, o rebanho, o ano de parto e a estação de parto foram importantes fontes de variação para a P305. Não houve diferença significativa entre as raças estudadas. As estimativas de herdabilidade e repetibilidade para a P305, obtidas com o modelo de repetibilidade, foram de 0,29 e 0,36, respectivamente. As estimativas de herdabilidade, obtidas pelos modelos de repetibilidade e bicaracterísticas foram semelhantes. Sendo assim, um modelo de repetibilidade poderia ser indicado para avaliar a P305 pela sua simplicidade. Palavras-chave -Caprinos-produção de leite. Genética animal. Leite de cabra.Abstract -The objective of this study was to estimate genetic parameters for 305 days milk yield (M305) in Saanen and Alpina breed goats. Data consisted of records from first to second lactations of goats belonging to herds participating in the program control productive and reproductive goats (PROCAPRI) from UNESP-FCAV-Jaboticabal-SP. The M305 was analyzed by repeatability and bi-trait models. The influence of fixed effects on the traits was analyzed preliminary analysis by the method of least squares. Variance components were estimated by restricted maximum likelihood method (REML), using the package Wombat. The duration of lactation, age of dam at calving, the herd, calving year and season of birth were important sources of variation for the M305. There was no significant difference between the breeds. Heritability and repeatability estimates obtained by repeatability model were 0.29 and 0.36, respectively. The repeatability estimate was 0.32. The heritability estimates obtained by the bi-trait models were similar and repeatability. Thus, a repeatability model might be indicated for its simplicity.

Dairy goat production in the semi-arid region: productive and reproductive analysis, and the influence of the adoption of hygienic practices on milk quality

“…These values are higher than the reported by Facó et al (2007) who worked with Anglo Nubian dairy goats in a semi-intensive system and observed a lactation length of approximately 141 days. However, the lactation length observed in this study was lower than Alpine and Saanen goats in southeastern region (211 days) (Irano et al, 2012). If it was compared the results with those reported by Santos and Santana (2011), who found LL averages of 168 and 251 days for the Anglo Nubian and Saanen breeds, respectively, it appears that the survey means follow the trend of genotypes.…”

Breeding programs for dairy goats generate profits in Brazil

“…The values were weighted by the number of goats (100) used to estimate these weights because ZPLAN requires economic values relating to a dam without considering the time and amount of expression in later generations. Mean values of traits and their standard deviations (Table 3) were calculated by Irano et al (2012), except for AFK and KI, which was reported by Lôbo and Silva (2005). The values for somatic cell count, dry milk solids, protein and fat content were estimated from the CAPRA-GENE databank.…”

Characterization of milk production and composition of four exotic goat breeds in Brazil

“…However, these means were estimated from one or a few flocks in a certain period of time stationary (single lactation, one year, etc.) or sample taken from the cooling tank (Ciffoni, 1998;Gonçalves et al, 2001Gonçalves et al, , 2002Irano et al, 2012;Ribeiro et al, 2000;Souza et al, 2009;Tholon, 2000). The averages obtained in this way are not sufficient to characterize a parameter of the population.…”