Suplementación de la dieta de ovejas lecheras con aceite de girasol y taninos: 1. Efecto sobre la fermentación ruminal, el rendimiento productivo de los animales y la composición de la leche

Abstract

Fourteen Assaf ewes in mid lactation were used to examine the effect of the addition of a mixture of two commercial extracts of condensed and hydrolysable tannins to a diet containing sunflower oil, on animal performance, milk yield and composition, and ruminal fermentation. All sheep received a total mixed ration based on alfalfa hay and a concentrate (F:C 40:60), supplemented with 20 g of sunflower oil/kg dry matter (DM) plus 0 (Control) or 10 (TAN) g of tannins/kg DM. Milk production and composition was analysed on days 0, 3, 6, 9, 12, 15, 18, 21, 24, and 27 on treatments. Neither DM intake nor milk- or its componentyield was affected by the TAN treatment (P>0.10). Similarly, the addition of the extract of tannins to a sunflower oil-containing ration did not affect ruminal fermentation parameters (pH, and lactate, ammonia, and total VFA concentrations) measured after 28 days on experimental diets. Probably the dose (10 g/kg DM), the type of tannins (a proportional mixture of quebracho CT and chestnut HT extracts) or both were responsible for the lack of significant effects. If these tannins were proved to favourably modify ruminal biohydrogenation of dietary fatty acids and, consequently, milk fat composition, they could be used in dairy ewe feeding without impairing the productivity.