Abstract
Simple SummaryAlthough the casein complex has been reported to condition economically important traits in dairy species, information in goats is scarce. The analysis of haplotypic sequences has been suggested to maximize the results obtained after the assessment of other genetic units, such as SNPs. We studied the association between haplotype sequences for αS1-, αS2-, β-, and κ-casein loci and milk yield, protein, fat, dray matter, lactose, somatic cells count, and the curve shape parameters that they describe during lactation (peak and persistence). This aimed to provide basic research data for the integration of haplotype monitoring in the selection strategies of dairy goats.Considering casein haplotype variants rather than SNPs may maximize the understanding of heritable mechanisms and their implication on the expression of functional traits related to milk production. Effects of casein complex haplotypes on milk yield, milk composition, and curve shape parameters were used using a Bayesian inference for ANOVA. We identified 48 single nucleotide polymorphisms (SNPs) present in the casein complex of 159 unrelated individuals of diverse ancestry, which were organized into 86 haplotypes. The Ali and Schaeffer model was chosen as the best fitting model for milk yield (Kg), protein, fat, dry matter, and lactose (%), while parabolic yield-density was chosen as the best fitting model for somatic cells count (SCC × 103 sc/mL). Peak and persistence for all traits were computed respectively. Statistically significant differences (p < 0.05) were found for milk yield and components. However, no significant difference was found for any curve shape parameter except for protein percentage peak. Those haplotypes for which higher milk yields were reported were the ones that had higher percentages for protein, fat, dry matter, and lactose, while the opposite trend was described by somatic cells counts. Conclusively, casein complex haplotypes can be considered in selection strategies for economically important traits in dairy goats.
Highlights
The inclusion of new technologic advances in breeding programs gradually evolved from the implementation of traditional phenotypic selection to genomic selection methods through single nucleotide polymorphisms (SNPs)
Total milk yield was standardized to 210 days in milk (DIM) and expressed in kg as described in Pizarro et al [22] following the premises described in the statutes of CAPRIGRAN (National Association of Breeders of Murciano-Granadina Goat Breed), given the methods performed have proven to be as accurate as the Fleischmann method as required in the guidelines in ICAR [23]
Provided the fact that the lower number of haplotypic variants was found for αS1-casein, the results will be presented comparing this to all potential haplotypic combinations found across the rest of casein complex loci
Summary
The inclusion of new technologic advances in breeding programs gradually evolved from the implementation of traditional phenotypic selection to genomic selection methods through single nucleotide polymorphisms (SNPs). The study of the association of SNPs may allow identification of which gene sequences may associate with goat milk production, quality, and composition, as well as cheesemaking properties [1,2,3]. SNPs have been reported to act as genetic units, which are closely bonded through epistatic relationships [5] and transmitted as haplotypes [6]. It is the relationship among the genetic polymorphisms of the casein complex (αS1 , β, αS2 , and κ-casein genes) with the aforementioned characteristics of productive interest that shapes one of the most interesting complexes to study from an economic perspective [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
