Influence of Prepubertal Dietary Regimen on Mammary Growth of Holstein Heifers

Abstract

One hundred-sixteen Holstein heifers (mean BW, 175 kg) were randomly assigned to diets of alfalfa silage or corn silage and were fed to gain approximately 725 or 950 g/d in order to study the influence of prepubertal diet and rate of gain on mammary growth and milk production. Blood was collected before puberty for hormone determination, and 8 heifers per group were killed at puberty for evaluation of tissue variables. Serum growth hormone was reduced, and IGF-I was increased, in the group of heifers reared at a high rate of gain on the corn silage diet. Accompanying the decline in growth hormone, total mammary parenchymal DNA and RNA was reduced in heifers reared at a high rate of gain on the corn silage diet. Mammary parenchyma in heifers of the latter group contained a greater volume of adipocytes and a lower volume of epithelial cells than did mammary parenchyma in heifers of other groups. Data are consistent with previous investigations that showed a deleterious effect of prepubertal rapid weight gain on mammogenesis when accompanied by excess body fat deposition. However, this effect did not cause a decline in subsequent milk production.

Effects of restricted feeding of prepubertal ewe lambs on growth performance and mammary gland development

“…This result is in agreement with data previously reported in ovines (Johnsson and Hart, 1985;Johnsson et al, 1986;McCann et al, 1989;McFadden et al, 1990;Peclaris et al, 1994 and1997) and bovines (Sejrsen et al, 1982;Capuco et al, 1995;Charles et al, 1999;Meyer et al, 2006). In rodents, mammary parenchymal development occurs by gradual invasion of the mammary fat pad.…”

“…Sejrsen et al (1982) found in dairy heifers that a 50% growth restriction improved parenchymal content in the mammary gland. Similarly, Capuco et al (1995) found lower DNA content in the mammary gland of dairy heifers fed a high plane of nutrition. Therefore, ewe lambs fed a high plane of nutrition, such as market lambs, during the allometric phase of mammary gland development will lay fewer duct cells in their mammary gland, which may compromise future milk production potential.…”

“…Earlier studies have shown that a high plane of nutrition during the first allometric period reduces mammary gland development in dairy heifers (Sejrsen et al, 1982), goats (Bowden et al, 1995) and ewes (Zidi et al, 2007) and also increases fat deposition in the mammary gland of heifers (Capuco et al, 1995;Charles et al, 1999) and ewes (Johnsson et al, 1986;Peclaris et al, 1994 and1997). During this period, duct extremities lengthen and ramify into the fat pad.…”

Regulation of mammary parenchymal growth by the fat pad in prepubertal dairy heifers: role of inflammation-related proteins

“…This possibility is suggested by situations where indices of parenchymal and MFP growth are inversely related. Specifically, expansion of the MFP in rapidly growing dairy heifers is associated with decreased parenchymal growth when assessed at a similar body weight (Sejrsen et al 1982, Capuco et al 1995. Moreover, cessation of allometric parenchymal growth occurs near 300 kg body weight when the MFP has expanded significantly (Meyer et al 2006b).…”

Effects of restricted feeding of prepubertal ewe lambs on reproduction and lactation performances over two breeding seasons

“…Accelerated gain before puberty reduces mammary secretory tissue in dairy heifers (Sejrsen et al, 1982) and in ewes (Zidi et al, 2007;Villeneuve et al, 2010). It also increases fat deposition in the mammary gland in heifers (Capuco et al, 1995;Charles et al, 1999) and in ewes (Johnsson et al, 1986; -E-mail: Lacassep@agr.gc.ca Peclaris et al, 1994Peclaris et al, , 1997Villeneuve et al, 2010). Restricted feeding in the prepubertal period improves milk production in the first lactation in dairy heifers (Foldager and Sejrsen, 1991;Peri et al, 1993;Hohenboken et al, 1995;Van Amburgh et al, 1998;Lammers et al, 1999;Radcliff et al, 2000) and in dairy ewes (Zidi et al, 2005).…”