Reproductive Disorders in Cattle due to Nutritional Status <Review>

This review presents a brief overview on nutrition and incidences of reproductive problems in cattle. Overfeeding and underfeeding are equally detrimental to normal reproductive function. The exact mechanism of nutrition on reproduction is still not clear, but it is clear that the primary target area for sensing and reacting to nutritional status is the hypothalamus. Nutrition or perhaps more specifically certain food nutrients can influence the hormonal status of animals at several levels. Generally, energy and protein are the major nutritional factors which affect reproductive process. Inadequate amount of energy develops sexual maturity in heifer cows with a low body condition score at parturition which have poor reproductive performance, possibly due to delay in onset of cyclicity. Cows overconditioned at calving will exhibit decreased appetite and develop severe negative energy balance which causes a linear decrease in the maximum diameter of successive dominant follicle, eventually resulting in anoestrus due to suppressed luteinizing hormone pulse frequency in the final oestrus cycle before anovulation. Dietary increase in protein intake can increase milk production, but can reduce fertility. It is due to the alterations in the oviduct environment or deleterious changes in the follicle. Besides these, deficiency of minerals and vitamins are also equally important from the viewpoint of infertility. However, the specific action of vitamins and minerals in reproduction needs further study. A multitude factors must be considered to understand the complex coordination of the nutrition-reproduction interface.