Effects of calcium salts of fatty acids (Megalac) on reproductive performance and blood parameters of Kalkohi ewes

To determine the effects of Megalac addition on Iranian ewesʹ reproductive parameters, a complete randomized design was used. Multiparous Kalkohi ewes (n = 32; 3 years old) were randomly assigned to 2 groups which consumed isoenergetic and isonitrogenous control (C) or Megalac (M; 5% Megalac in diet DM) diet. All ewes were synchronized by prostaglandin injection. Blood samples were collected from d 8, 10, and 12 of estrus cycle. Diets offered 4 wk prior to mating and up to 4 wk after mating and 2 weeks before parturition. Pregnancy, lambing and twining rate were not significantly affected by fat inclusion in ewe diet (P ? %5). Similarly, pregnancy length was unaltered by treatment (P ? %5). Lambing crop was affected by diet fat (P ? %5). Cholesterol concentration significantly increased as Megalac added to the diet (52.7 vs. 49.7 mg/dl in M and C, respectively; P ? %5), whereas P4 concentration was similar between M and C group in d 8, 10 and 12 of estrus cycle (3.80 and 3.81 nmol/L for M and C, respectively; P ? %5). This experiment suggests that fatty acid content and profile of this level of Megalac may be insufficient for improving ewesʹ reproduction performance, but 2.5 % Megalac in ewesʹ diet DM before parturition could improve lamb weight. The lack of changes in P4 concentrations alongside the increasing of blood cholesterol did not support cholesterol and P4 relation. However, further studies are needed to determine impact of various fat sources and levels on physiological responses in ewes.