Fat and Fat-Soluble Vitamin Supplementation for Improving Reproduction of the Dairy Cow

The scientific literature contains evidence that the nutrient status of lactating dairy cows can have a direct bearing on reproductive status. Pregnancy rate has been improved by manipulating the mineral (Hurley and Doane, 1989), vitamin (Seymour, 2001), energy (Butler, 2001), protein (Butler, 1998), and lipid fractions (Staples et al., 1998) of the diet. Nevertheless the amount of knowledge in this area is not great. Collective efforts of nutritionists, reproductive physiologists, immunologists, and veterinary practitioners and researchers are needed in order to advance our understanding of both the extent of potential impact and the physiological mechanisms by which these nutrients act in vivo. The challenge to characterize the factors contributing to conception and embryo development as well as developing strategies to use to improve embryo survival is complex involving steroidogenesis, cell proliferation, follicle development, ovulation, fertilization, corpus luteum development and maintenance, oviductal and uterine functions, embryo implantation and subsequent fetal growth. Indeed our current daily production and reproductive management systems impact all of these coordinated events and need to be optimized if reproductive efficiency in lactating dairy cows is to be enhanced. Dietary vitamins A and E, protein, fat, and phosphorus are nutrients selected to briefly review in this paper in terms of their potential impact on reproductive health and fertility of dairy cows.