Abstract

The placenta is the organ responsible for exchange of nutrients and waste products between the mother and her fetus (Bell & Ehrhardt 2002). It is therefore the main regulator of fetal growth (Murphy et al. 2006). In sheep, placental exchange of nutrients occurs at sites called placentomes (Ford 2000). Placentomes are comprised of cotyledons on the chorioallantoic membrane which attach to discrete caruncles on the uterine wall (Ford 2000). Ovine placentomes can be classified into four types (A, B, C and D) based on their gross morphological appearance (Vatnick et al. 1991). The distribution of placentome type, and size of individual placentomes can be influenced by many factors.These include nutritional status of the dam, placental blood flow, oxygen availability and altitude (Gardner et al. 2002; Osgerby et al. 2002, 2004; Penninga & Longo 1998).

van der DS, Linden, MR Oliver, and SA McCoard

Proceedings of the New Zealand Society of Animal Production, Volume 73, Hamilton, 90-92, 2013