Genetic parameters for total lactation yields of milk, fat, protein, and somatic cell score in New Zealand dairy goats

Abstract

Dairy goat farming in New Zealand is a profitable industry able to access niche markets for high value products. The New Zealand Dairy Goat Cooperative's members collectively manage 80% of the nation's dairy goat population (Scholtens et al., 2017). The cooperative is the leading international manufacturer of goat milk nutritional powders for infants and young children (Stafford & Prosser, 2016). The industry is dependent on goat milk with high total milk solids and low bacterial count for the manufacture of high-quality products. Selecting animals based on a selection index utilizes estimates of genetic merit encompassing economically relevant traits. A breeding program would enable the index selection of genetically superior animals which would rapidly improve the quantity and quality of milk produced from New Zealand dairy goats and result in improved profits for farmers. Modern breeding programs include routine genetic evaluation to enable selection of the best parents to produce the next generation of animals. Genetic and environmental factors significantly influence milk yield and quality in ruminants (Selvaggi & Dario, 2015), and genetic gain from selection will be enhanced if these environmental factors are accounted for in the estimation of genetic merit. Knowledge of variance components for production traits will enable the design of an effective genetic evaluation strategy, allowing the selection of animals with superior overall genetic merit, optimizing direct, and correlated selection responses for traits of economic importance (Barillet, 2007). Estimates of genetic parameters for economically relevant traits have been reported for dairy goats in South

Genome-wide association studies of lactation yields of milk, fat, protein and somatic cell score in New Zealand dairy goats

“…The chains include 20,000 iterations after a burn-in of 1,000 iterations. For this model the priors for the genetic and residual variances were based on posterior means in a previous analysis [30]. It was assumed that 99.8% of the SNPs have no effect on the trait.…”

Genetic parameters for somatic cell score, milk yield and type traits in Nigerian Dwarf goats

“…Saanen breeds in France (from -0.13 to 0.12) [23], and f or New Zealand dairy goats (from -0.01 to 0.10) for these same traits [15]. Results for ND were positive but small and not different from zero.…”

Advantage of including Genomic Information to Predict Breeding Values for Lactation Yields of Milk, Fat, and Protein or Somatic Cell Score in a New Zealand Dairy Goat Herd

“…Due to the limited number of observations in this evaluation (a single herd), variance components were estimated using the ssBC model and data from a larger dataset first (phenotypic records from 24,317 individuals and 41,981 markers on 2681 individuals). The posterior residual variance and heritability values previously estimated for this population [ 19 ] for each of the traits were used to calculate the total genetic variance. The “known” variance components were then considered to be the parametric values in the PBLUP and ssBC models ( Table 1 ).…”