The morphology of placentomes and formation of chorionic villous trees in West African Dwarf goats

Gravid uteri, harvested from 11 pregnant West African Dwarf (WAD) goats at different stages of gestation, were used to study the morphology of placentomes and the formation of chorionic villous trees in the placentomes. The results showed that the goats exhibited a polycotyledonary placenta, made up of randomly distributed concave placentomes. The number of placentomes in the placenta did not vary (P > 0.05) with gestational age, but the average size of the placentomes increased linearly ([R.sup.2] = 0.978; P < 0.05) as pregnancy progressed. The indication is that the conceptus of WAD goats responds to the greater nutrient/metabolic demands of late pregnancy by increasing the size of placentomes but not the number of placentomes in the placenta. Histological observations revealed that primary chorionic villi were present in the superficial layers of the uterine caruncles, but were lacking in the subjacent (deep) caruncular tissue layers during the peri-implantation period. Furthermore, complete apposition and attachment were observed between the chorionic villi and caruncular crypts at al stages during the formation of the placentomes. It was concluded that the caruncular crypts and chorionic villi appear to develop simultaneously in the placentomes of West African Dwarf goats. Key words: cotyledonary placenta, placentome, chorionic villi, caruncular crypt Maternice od 11 zapadnoafrickih patuljastih koza, u razlicitim stupnjevima gravidnosti, upotrijebljene su za istrazivanje morfologije placentoma i tvorbe stabla korionskih resica u njima. Rezultati su pokazali postojanje polikotiledoidne posteljice gradene od nasumce rasporedenih konkavnih placentoma. Broj placentoma u posteljicama nije se razlikovao (P > 0,05) ovisno o stupnju gravidnosti, no prosjecna velicina placentoma linearno se povecavala ([R.sup.2] = 0,978; P < 0,05) s vecim stupnjem gravidnosti. Pretpostavlja se da zapadnoafricke patuljaste koze na povecane hranidbeno/metabolicke zahtjeve u kasnoj fazi gravidnosti odgovaraju povecanjem velicine, ali ne i broja placentoma u posteljici. Histoloska istrazivanja pokazala su prisutnost primarnih korionskih resica u povrsinskim slojevima maternicnih karunkula. Istih nije bilo u dubljim slojevima tkiva karunkula tijekom perimplantacijskog razdoblja. Opazeno je i potpuno pripajanje, odnosno povezivanje, korionskih resica i kripti karunkula u svim stupnjevima formiranja placentoma. Zakljuceno je da se razvoj kripta karunkula i korionskih resica u placent