Effects of starch and fatty acids source on performance, milk yield and composition and nutrients digestibility of Qezel ewes during transition period

The transition period of dairy animals is most important because of the sudden and profound physiological and metabolic changes in the course of transition from pregnancy to lactation. The use of different energy supply methods by glucogenic or lipogenic diets during the pre and post partum periods has been recognized as the main strategies for prevention of metabolic diseases and increasing the pregnancy efficacy. The purpose of this study was to evaluate the effects of different sources of starch and fatty acids on performance, milk yield and composition and nutrients digestibility of Qezel ewes during transition period.

20 pregnant Qezel ewes with average age of 3 years and average body weight of 65 ± 2 kg from 30 days to the expected time of parturition until 30 days after parturition in a completely randomized design and implemented with 2×2 factorial method. Treatments included: 1) Corn-based diet + Saturated fatty acids (palmitic acid supplement (Roomi Fat)®); 2) Corn-based diet + unsaturated fatty acids (Omega-3 fish) (Persia fat) ®); 3) Barley-based diet + Saturated fatty acids (palmitic acid supplement) and 4) Barley-based diet + unsaturated fatty acids (supplement omega-3 fish). Ewes had a free access to water and feed intake was a ad libitum. Feed intake was measured a daily.

The results of this study showed that the starch and fatty acids source had no significant effect on digestibility of dry matter, organic matter, protein, ether extract and ash (P >0.05). The starch and fatty acids source had no significant effect on feed intake before and after parturition and birth weight of lambs (P >0.05). After parturition, the effect of starch and fatty acids source on the ewes weight changes was significant and in the ewes fed diets containing barley grain, weight loss was higher than corn grain diets (P <0.05). Milk production and milk protein was not affected by the source of starch and fatty acid (P >0.05). Milk fat percentage in treatments containing barley grain was significantly higher than corn grain (P <0.05), as well as in barley-containing treatments, supplemental palmitic acid treatment had a higher milk fat percentage than diets containing of omega- 3 fatty acid.

The results of this study showed that the use of corn grain and supplementation of saturated fatty acid would reduce the weight loss in ewes after parturition, which confirmation of these results requires more functional and metabolic experiment.