Abstract

This study evaluated the effects of maternal nutrition, weight and gestation rank on fetal mammary gland development. Light (L) and heavy (H) single- and twin-bearing ewes were fed ad libitum (A) or maintenance (M) nutritional regimens from day 21 to day 140 of gestation and euthanised for tissue collection. Plane of maternal nutrition or maternal weight did not affect histomorphometry of fetal mammary glands. Singleton fetuses had 43% greater total duct area (P<0.05), 62% greater secretory cell area and 32% fewer ducts (P<0.05) but similar total lumen area, cell size and total cell number than twins. These results indicate that twinning reduces area of mammary ducts and secretory cell area while maternal weight and plane of nutrition from day 21 have little impact on mammary morphology at day 140 of gestation.

SA, McCoard, AM Adiletta, CMC Jenkinson, SW Peterson, PR Kenyon, and HT Blair

New Zealand Journal of Animal Science and Production, Volume 78, Lincoln, 183-185, 2018