The effect of male co-twins on milk and kid production, and productive lifespan of goats during their adult life

Abstract

Kidding (n = 33,116) and monthly milking control (n = 96,359) records of Florida goats (n = 13,194) from the Spanish Florida Goat Breeders Association, collected between 2007 and 2016, were used to determine whether the presence of male co-twins affected the productive lifespan, and kid and milk production of does. The dataset included single-born (n = 3727), twin-born (n = 7573), triplet-born (n = 1784) and quadruplet-born (n = 110) goats. Information for each goat included birth date; type of birth (single, twin, triplet, or quadruplet), sex of the co-twin(s), reproductive traits of the goat throughout its productive life, and mean milk quality and quantity of the lactations. Singleton and twin-born goats had significantly longer productive lifespans than did triplet- (P < 0.05) or quadruplet-born animals (P < 0.01). Females born with male co-twins had a shorter (P < 0.05) productive lifespan than did goats born with no male co-twins, and had more parturitions and kids born per year (P < 0.05). In particular, goats that had three female littermates had the fewest kids per year (P < 0.01). Does born with male littermates had a higher daily milk yield and total milk yield (P < 0.01) than did goats born with no male co-twins; however, the former had the shortest on-farm longevity, which caused them to have a lower (P < 0.05) lifetime milk production than did goats born with no male co-twins. In conclusion, the presence of male co-twins had a positive effect on the production traits of dairy goats; however, the shorter reproductive lifespan of these goats limited their lifetime milk production. If reproductive lifespan could be extended, possibly through management practices or by identifying the factors that reduce lifespan, goats that have male co-twins might be the most suitable candidates for replacement does. Thus, in addition to litter composition, kid body mass, or maternal milk production, the sex of co-twins might be included in selection programs.