Genetic parameters of total milk yield and factors describing the shape of lactation curve in dairy buffaloes

Abstract

The objective of this study was to apply factor analysis to describe lactation curves in dairy buffaloes in order to estimate the phenotypic and genetic association between common latent factors and cumulative milk yield. A total of 31 257 monthly test-day milk yield records from buffaloes belonging to herds located in the state of São Paulo were used to estimate two common latent factors, which were then analysed in a multi-trait animal model for estimating genetic parameters. Estimates of (co)variance components for the two common latent factors and cumulated 270-d milk yield were obtained by Bayesian inference using a multiple trait animal model. Contemporary group, number of milkings per day (two levels) and age of buffalo cow at calving (linear and quadratic) as covariate were included in the model as fixed effects. The additive genetic, permanent environmental and residual effects were included as random effects. The first common latent factor (F1) was associated with persistency of lactation and the second common latent factor (F2) with the level of production in early lactation. Heritability estimates for F1 and F2 were 0·12 and 0·07, respectively. Genetic correlation estimates between F1 and F2 with cumulative milk yield were positive and moderate (0·63 and 0·52). Multivariate statistics employing factor analysis allowed the extraction of two variables (latent factors) that described the shape of the lactation curve. It is expected that the response to selection to increase lactation persistency is higher than the response obtained from selecting animals to increase lactation peak. Selection for higher total milk yield would result in a favourable correlated response to increase the level of production in early lactation and the lactation persistency.

Genetic Parameter Estimates for Production and Reproduction Traits in Dairy Buffaloes

“…As a consequence, direct selection for one trait could result in correlated genetic gains in the other. The genetic correlation observed agrees with estimates reported by Tonhati et al (2000a), Rosati andVan Vleck (2002), andAspilcueta-Borquis et al (2010). (Table 4).…”

“…Similar results have been reported in studies conducted in Brazil, with estimates ranging from 0.20 to 0.25 (TONHATI et al, 2000a;MALHADO et al, 2007;RODRIGUES et al, 2010;SENO et al, 2010;ASPILCUETA-BORQUIS et al, 2012). In contrast, Rosati and Van Vleck (2002), studying an Italian buffalo population, estimated a heritability of 0.14 for MY.…”

“…Moderate heritabilities for milk yield (MY), ranging from 0.20 to 0.25, have been reported for buffaloes (MALHADO et al, 2007;ASPILCUETA-BORQUIS et al, 2010;RODRIGUES et al, 2010;SENO et al, 2010). These results suggest there is sufficient additive genetic variation to respond to selective breeding.…”

Characterization of protected designation of origin Italian meat products obtained from heavy pigs fed barley-based diets1

“…The FA has had only limited application in animal science research fields, and it was used to asses dairy herd management (Enevoldsen et al, 1996), to evaluate relationships between herd life and several type traits (Vukasinovic et al, 1997), to model the shape of lactation curve (Macciotta et al, 2004(Macciotta et al, , 2006Aspilcueta-Borquis et al, 2012), or to develop a corn silage fermentative quality index able to properly rank well and poorly preserved silages (Gallo et al, 2015a,b). To the best of our knowledge, no studies applied FA for meat and derived product evaluations.…”

Analysis of Liver Proteome and Identification of Critical Proteins Affecting Milk Fat, Protein, and Lactose Metabolism in Dariy Cattle with iTRAQ

“…There were many hepatic genes involved in milk synthesis activated during the transition period from gestation to lactation, and the corresponding mRNA abundance have the obvious differences . The lactation peak normally occurs 2 months after calving, and the milk yield increases gradually from early lactation to peak of lactation . These data showed that the three serial periods of lactation cycle (dry period, early lactation, and peak of lactation) demonstrate various physiological state, substance metabolism, and expression of some genes.…”