Effects of calcium salts of fatty acids (CSFA) with different profiles (ω3 and ω6) during the flushing period on reproductive performance of ‘Afshari’ ewes

• Effects of dietary supplements of calcium salts of fatty acids were studied.
• Fertility and lambing rates in non-flushing diet was greater for CFSA than barley.
• Serum cholesterol, progesterone and estrogen levels were highest for CSFA groups.
• CSFA during flushing period increased reproductive performance and lamb birth weight.

The effects of supplementing the flushing diet of Afshari ewes with calcium salts of fatty acids (CSFA) with different profiles (ω3 and ω6) on their reproductive performance were studied using 48 sheep weighing 46 ± 3 kg and 2–3 years old. The ewes were assigned to four groups (n = 12 per group) and within a group received one of four diets for the period from the start of estrous synchronization to the end of mating (5 weeks). The diets all contained wheat bran (10%), wheat straw (37–40%), alfalfa (25–41%) and barley grain (7–25%). The control group received the basal (non-flushing) diet only. The remaining three groups received isoenergetic and isonitrogenous diets with higher energy contents formulated to meet the ewes’ requirements during the flushing period. In the Barley group, the basal diet was enhanced using additional barley grain; in the CaFl group the flushing diet included 5% of DM as flaxseed oil (ω3 CSFA); and in CaSf group the diet was supplemented with 5% of DM as sunflower oil (ω6 CSFA). The estrous cycles of the ewes were synchronized by application of a CIDR for 14 d and administration of 400 units of PMSG at CIDR withdrawal. Afshari rams were introduced to the ewes 36 h later and the experimental diets continued to be fed for a further 3 weeks. The fertility and lambing rates were higher for Barley (91.7%; 125%), CaFl (100%; 150%) and CaSf (100%; 116.7%) than for the Control (83.3%; 83.3%). The number of lambs produced was significantly on the flushing treatments than the control. Serum cholesterol and progesterone levels were significantly higher on the diet supplemented with flaxseed oil (CaFl) than the other treatments. The results showed that supplementing the flushing diet with CSFA increased blood metabolites and hormones related to reproductive performance; and improved fertility, lambing rate and lamb birth weight. Ewes on the flaxseed oil supplemented flushing diet had the highest values for these variates. It was concluded that supplementing the flushing diet of ewes with flaxseed oil to provide a source of ω3 CSFA produces beneficial responses in their reproductive performance.