Effect of supplemental yeast culture and physiological factors on colostrum and milk composition of Pelibuey ewes.

The effects of supplemental yeast culture, litter size, stage and number of lactation on milk composition were studied in Pelibuey ewes. Twenty ewes were randomly assigned to one of two dietary treatments. Ten control ewes grazed on guinea grass (Panicum maximum) and were supplemented with concentrate. A further ten ewes received the same diet with 14 g/head/day of yeast culture (Saccharomyces cerevisiae). Colostrum was collected within 24 h after parturition, and subsequently, milk samples were collected at fortnightly intervals (7, 21, 35, and 49 days). Total solids content averaged 32% in colostrum and 12.5% in milk. Colostrum of primiparous ewes had higher total solids content than that of ewes with more than five lactations. However, ewes with more than five lactations produced milk with higher net energy, total solids, protein, and casein than ewes with fewer lactations. Milk at 7 days had a significantly higher content of energy, total solids, and fat than milk at 21, 35, and 49 days. Total solids content was lower for ewes rearing one lamb than larger litter sizes. Supplementation with yeast culture did not affect the composition of colostrum and milk, which was mainly affected by the stage and number of lactation.