Effects of oxytocin treatments on milk ejection in dairy goats traditionally milked once a day.

Goats in Canary Islands are milked once a day, so they are adapted to accommodate large volumes of milk into their cisterns between milkings. Therefore it is important to know whether the oxytocin release by the stimulation of the mammary gland can increase the milk production when the goats are not milked immediately after the stimulation. Thirty-nine dairy goats in mid lactation (95±10 d in milk) were divided into 3 groups (n=13) on the basis of similar milk yields. During a period of 8-week, the goats from group 1 (OT1) were introduced to the milking parlor once a week, 10h after milking, and all pre-milking routines were carried out, including 2 to 3 stripping squirts of milk from each teat. However, the animals were not milked. During this period, the goats from group 2 (OT2) were injected intravenously with 2IU of oxytocin once a week, 10h after morning milking, while being placed in the crowd pen. However, the animals were not milked. The goats from group 3 (control) remained in the pen without any treatment. Milk recording and sampling were done the next day at the morning milking. Milk yield and milk composition in treatments OT1 and OT2 and control did not differ. The results suggest that oxytocin release by milking procedures or by administration of synthetically manufactured oxytocin did not reduce the content of milk in alveoli in dairy goats, which are not milked immediately. [ABSTRACT FROM AUTHOR]