Estimation of genetic parameters for milk yield in Murrah buffaloes by Bayesian inference

Abstract

Knowledge of genetic parameters is essential for improved reproductive management and increased yield. Quantitative analysis of genetic parameters is lacking for many breeds of buffaloes. This article provides the first estimate of genetic parameters for dual purpose (meat and milk) Brazilian Jaffarabadi buffaloes, using Bayesian inference. Data on milk yield (MY), lactation length (LL), weight at 205 days (W205) and 365 (W365) days of age, and average daily gain (ADG) from 205 to 365 days of age were collected in two herds. Bivariate analyses (using the program MTGSAM) were performed with the Gibbs sampler to obtain estimates of variance and covariance. Average lactation milk yield and lactation length were 1 620.2±450.9 kg and 257.6±46.8 days, respectively, and the mean values for weight traits (kg) were 181.6±63.3 (W205), 298.04±116.1 (W365), and 0.73±0.35 (ADG). Heritability estimates (modes) were 0.16 for MY, 0.10 for LL, 0.43 for W205, 0.48 for W365 and 0.32 for ADG. There was a high genetic correlation (0.96) between milk yield and lactation length and very high genetic correlations (0.99) between the three growth traits. Our data suggest that both milk production and growth traits have clear potential for yield improvement through direct selection in this dual purpose breed. The selection for weight at an early age would be successful and selection for MY can be performed in the first lactation.

Random regression models to estimate genetic parameters for test-day milk yield and composition in Iranian buffaloes

“…The selection could be anticipated by promoting a reduction in the generation interval. In the present study, the heritability for the milk yield (0.09 to 0.33) was higher than that reported by Hurtado-Lugo et al (2006) for Murrah buffaloes in Colombia (0.01 to 0.20) and was consistent with the report of Chakraborty et al (2010) and Breda et al (2010) who reported that the heritability estimates for the TDMY were low to medium in Murrah buffaloes. The current heritability estimates ranged from 0.03 to 0.24 for TDF (Table 3).…”

“…Also, the lowest milk yield was observed in the 270th day of lactation. Breda et al (2010) reported that the peak period of milk production of Murrah buffaloes was observed around the 11th week of lactation. Hurtado-Lugo et al (2009) observed the highest values of the TDMY towards the middle of the lactation in Colombia North buffaloes.…”

“…According to Misztal et al (2000), there are marked differences between the estimates of genetic parameters obtained with different random regression models. These differences might be attributed to the small number of milk yield records or to the models and functions used to describe the random regression (Breda et al 2010).…”

Random regression models using different functions to estimate genetic parameters for milk production in Holstein Friesians

“…Heritability estimates by WF.33_HE2 and LEG.33_HE2 models were similar, ranging from 0.31 to 0.50, with a tendency to overestimate the beginning and the end of lactation (Figure 2), in agreement with those reported by BREDA et al (2010) andSANTOS et al (2014). The LEG.55_HE4 diverged from these, in early lactation with higher estimates and from the 16 th fortnight with lower estimates.…”

Estimates of genetic parameters for total milk yield over multiple ages in Brazilian Murrah buffaloes using different models

“…RRM have been applied to model the population mean trend and random effects for first lactation test-day milk records (Breda et al, 2010;Sesana et al, 2010) and for 305-day milk yield (MY305) records over multiple parities (Guo et al, 2002). By applying RRM, the covariance functions that give the covariance between any two ages or lactations, within the range of age in the data, can be estimated and impose a structure on the covariance matrices (Meyer, 1998).…”