Genome-Wide Association Study for the Capacity to Skip the Dry Period in Dairy Goats

Lactation is a challenging life stage for dairy animals, as they need to cope with milk production and, in most cases, simultaneous pregnancy. The dry period between two consecutive lactations can be a producer choice, based on, for instance, animal performance or a physiological requirement when animals dry off spontaneously. The goals of this research were to estimate genetic parameters and perform a genome-wide association study in Saanen goats for the capacity to skip the dry period between lactations to identify genes and QTLs underlying this trait. A total of 249 Saanen dairy goats had the length of their dry period determined over lactations, with some (n = 54) showing the capacity to skip the dry period, i.e., having a dry period of a single day. The estimated heritability for the capacity to skip the dry period was moderate (0.25, SE = 0.13). Three SNPs significantly associated with the capacity to skip dry period were identified, which are located close to the OSMR gene, reported to be associated with mammary involution, and a known QTL for cannon bone circumference. The three SNPs were also confined to a very conserved region on chromosome 20, which harbors several genes associated with milk-related traits. The OSMR gene seems to be a good candidate gene for the capacity to skip the dry period, and the genomic region where it is located appears to also be important for milk production traits.