Abstract

In sheep, placental exchange of nutrients between the ewe and her fetus 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 on the basis of their gross morphological appearance (Vatnick et al. 1991). The distribution of placentome type and size of individual placentomes can be influenced by many factors such as, nutritional state, placental blood flow and oxygen availability (Gardner et al. 2002; Osgerby et al. 2004). In general, previous work has shown that adverse intrauterine conditions early in pregnancy lead to a shift to more everted placentomes (more C and D types) (Osgerby et al. 2004; Vonnahme et al. 2006).

van der DS, Linden, Q Sciascia, F Sales, and SA McCoard

Proceedings of the New Zealand Society of Animal Production, Volume 72, Christchurch, 210-212, 2012