Post-Partum anoestrus is lengthened by a thin body condition (Whitman, 1975) and malnutrition (Holness, Hopley and Hale, 1978). Post-partum nutrient intake has been implicated in both pituitary (Rutter and Randel, 1984) and ovarian (Wiltbank, Rowden, Ingalls and Zimmerman, 1964) function. Other post-partum studies, however, have shown a negligible effect of nutrition on either the pituitary (Spitzer, Niswender, Seidel and Wiltbank, 1978) or the ovary (Carstairs, Morrow and Emery, 1980). The lack of agreement among these studies may be due to an inability to control nutrient intake in all cows in a group feeding situation, or to a lack of nutrient restriction in many of the cows on a mildly restrictive diet. Furthermore, it is not clear when post-partum energy restriction is most deleterious to fertility. The objectives of this study were to examine the effect of a known individual energy intake on (i) post-partum length, and (ii) the ovarian follicular population at different stages post partum.

A Number of experiments Bhattacharya and Sleiman, 1971; Bhattacharya and Lubbadah, 1971; Castle, 1972; Castle, Gill and Watson, 1981) have shown that dried sugar-beet pulp is equal to barley in feeding value when included in the concentrate portion of the diet given to milking dairy cows. In recent years, there has been increasing interest in feeding the undried pulp, from which some of the moisture has been removed by heavy presses. This product is known as ‘pressed pulp’.