Effect of Plane of Nutrition on Mammary Gland Development in Prepubertal Goats

Abstract

A high plane of nutrition fed prior to puberty has been shown to negatively affect mammary gland development in heifers by decreasing secretory tissue and increasing adipose tissue (Sejrsen et al.,1982; Stelwagen and Grieve, 1990). Heifers reared on a high plane of nutrition have been shown to have depressed milk yields throughout their productive lives (Peri et al., 1992). Presently, it is not known why a high plane of nutrition inhibits mammary parenchymal development. Hormones and local growth factors play an important role in mammary gland development (Plaut, 1993). It is possible that a high plane of nutrition alters levels of hormones or growth factors that are needed for parenchymal development. Because heifers take up to 10 months to reach puberty, research in this area has been limited. Goats reach puberty 3–5 months sooner than heifers, therefore a similar study of caprine mammary development could be carried out in almost half the time. This study was conducted to test the usefulness of goats for such studies, and to test if a high plane of nutrition affects prepubertal mammary development.