The Effects of Saturated and Polyunsaturated Fatty Acids on Reproductive Performance and Reproductive Hormonal Changes in Dairy Cows at the Transition Period

Abstract

Reproductive success is crucial in dairy farming as it heavily relies on the consumption of a complete mixed ration for the diet. The current study investigated the effects of adding saturated (SFA) and polyunsaturated fatty acids (PUFAs) to dairy cows' diets on reproductive performance and reproductive hormones during the transition period. A total of 30 Holstein dairy cows were randomly divided into three groups (10 animals in each group), based on parity and body condition score. The cows had an initial body weight of 567.5 ± 40.3 kg (mean ± SD), a body condition score of 3.5 ± 0.26 out of 5 (mean ± SD), and a parity of 1.7 ± 0.02 (mean ± SD). The control group received a balanced ration meeting all the nutrient requirements according to the National Research Council (NRC) guidelines. The SFA group received 1.4% of dry matter (DM) as palm oil (RumiFat®), while the omega group had 5% of DM as safflower (a source of n-6 fatty acids) added from 21 days before parturition to 21 days after, and 4% of DM as flaxseed (a source of n-3 fatty acids) added from 21 to 42 days after parturition. In the Omega group, estradiol concentration significantly increased on artificial insemination (AI) day (12.54 pg/mL). Additionally, serum prostaglandin F2-alpha concentration was significantly higher in the omega group (0.732 pg/mL on day 7 and 1.68 pg/mL on day 14) compared to other groups. The control group exhibited the highest progesterone concentrations at 14 and 21 days post-calving compared to the other groups, other groups. whereas the omega group highest concentration five days after AI. The omega group also showed a significantly higher mean number of follicles >10mm and larger ovulatory follicle diameter. Moreover, a higher percentage of pregnant cows at 120 days in milk, fewer open days, and lower service per conception were observed in the omega group compared to the other groups. In conclusion, supplementing dairy cows' diets with PUFAs during the transition period positively influenced ovarian function, hormone levels, and reproductive performance.