Calcium soaps of olive fatty acids in the diets of Manchega dairy ewes: effects on digestibility and production.
Two experiments were carried out with dairy ewes to determine the effects of supplementation of calcium soaps of olive fatty acids at 10% of the basal diet on digestibility, roughage intake, milk production and composition, and response to early induced ovulation. The addition of calcium soaps of olive fatty acids to the diets of dairy ewes significantly decreased the digestibility of dietary dry matter but not the digestibility of other components. The digestibility of crude fat was enhanced. Voluntary intake of roughage, with fixed concentrate allowances, was slightly, but not significantly, reduced for ewes fed the supplemented diet. After weaning at 35 d postpartum and during the next 5-wk period of twice daily milking, ewes fed the supplemented diet produced more total solids in milk than did ewes fed the basal diet. Ewes fed the supplemented diet also tended to produce more milk protein, and milk energy and tended to have greater milk fat percentages. The composition of milk fatty acids was changed by the calcium soaps of olive fatty acids. Fewer short- and medium-chain fatty acids (C6:0, C8:0, C10:0, C12:0, C14:0, and C16:0), less C18:2, and more C18:1 and C18:0 were obtained in the milk of ewes fed the supplemented diet. Responses to ovulation induced at 60 d after lambing, while ewes were still lactating, were significantly higher for ewes fed the diet supplemented with calcium soaps of olive fatty acids than for ewes fed the basal diet. The calcium soaps of olive fatty acids appeared to be a useful source of energy for dairy ewes, and dairy ewes may be a good model for the study of the effects of nutrition during early lactation on reproductive performance of dairy ruminants.