Reproduction and Fertility Parameters of Dairy Cows Supplemented with Omega-3 Fatty Acid-rich Canola Oil

Dietary supplementation of lactating dairy cows with fat has long been used as a management tool to increase the energy density of feeds, improving milk production, reproduction and alleviating the menace of postpartum negative energy balance. In this paper, we show that while attempts have been made to investigate the effects of omega-3 (n-3) polyunsaturated fatty acid (PUFA) on reproduction and fertility parameters the results have been diverse and inconsistent. The effect of n-3 fatty acids on prostaglandin F2α (PGF2α) synthesis are well established, however, little is known about the effect of n-3 PUFA on progesterone, oestrogen, luteinising hormone, follicle stimulating hormone, insulin-like growth factor-1(IGF-1) and fat related genes linked to reproductive performance. There is contrasting evidence linking n-3 PUFA with ovulation, oestrous cycle, PGF2α and progesterone production. In addition, the mechanisms behind the influences of n-3 PUFA on reproductive traits such as, number of services per conception and embryo survival are not well understood. Therefore, this paper reviews the effect of n-3 PUFA on cow reproduction and the causal factors of fertility problems in the dairy industry. It also substantiates the need to establish a better understanding of the interactions between n-3 PUFA and cow fertility, with the aim of ameliorating the progressive subfertility issues emerging in the dairy industry. This review also summarizes the identified knowledge gaps and highlights fruitful directions for future research on high producing dairy cows in pasture-based systems.