ARTIFICIAL LONG DAYS INDUCE AN INCREASE OF MILK YIELD IN ALPINE GOAT

Abstract

The aim of this study was to determine if the use of artificial long days during winter and spring improve milk production in Alpine goat raised in Northern Mexico. Control Group (CG; n=14), was exposed to naturals photoperiod variations of the region during the whole experimental period (10 h and 19 min in the winter solstice), while the Experimental Group (EG; n=15), subject, from December 1st to April 19th, to a constant long day treatment (16 h light/8 h dark). At the onset of the trial (day 0 = 45 ± 0.6 postpartum days) milk yield was not different (P>0.05) between both groups. However, the EG group depicted an increase (15%) in milk yield from d-14 to d-112 with respect to the CG group (3.2 ± 0.07 vs. 2.7 ± 0.06 l/day/animal EG vs. CG; P<0.05). These results show that, during winter, exposition to long artificial days induces milk production increases in Alpine goat raised in Northern Mexico. Further studies are required to evaluate if long photoperiodic treatment affects the hormonal reproductive status of dairy goats.