Macroscopic evaluation of the placenta of the alpaca (Vicugna pacos)

Abstract

Macroscopic evaluation of the placenta is an essential post‐partum examination in the alpaca and can be of special interest in case of abortion, premature birth or stillbirth. Since there are not many reference values regarding macroscopic properties of normal alpaca placentas, a small descriptive study was conducted. Only placentae from normally foaling alpaca mares, giving birth to healthy crias, after a full‐term and uneventful gestation (±350 days; range 335–360 days) were taken into account (N = 11). Crias weighed (±SD) 7.7 ± 2.25 kg (range 5.5–10 kg), while the mean weight of the full‐term placentas was 0.8 ± 0.19 kg, that is 10% of the bodyweight of the crias. The weight of the allantoamnion and chorion was 0.2 ± 0.07 kg and 0.5 ± 0.13 kg, respectively. The umbilical cord length was 8.8 ± 2.84 cm, and the length of the pregnant and non‐pregnant uterine horns was 69.4 ± 12.77 cm and 54.5 ± 6.81 cm, respectively. The length of the corpus was 14.6 ± 4.68 cm, and the distance from the umbilicus to the corpus was 18.5 ± 6.13 cm. The tissue volume of the allantoamnion was 0.14 ± 0.079 L, and the chorionic volume was 0.37 ± 0.078 L. The surface area of the allantoamnion and the chorion was 87.6 ± 15.56 dm2 and 72.3 ± 9.28 dm2, respectively. All placentas had small calcifications either around the umbilical cord alone or around the umbilicus and blood vessels of the pregnant uterine horn. These measurements could be used to macroscopically evaluate alpaca placentas, although more research is needed to extend our knowledge of macroscopic evaluation of normal and abnormal placentas.

On-field Gross Morphology Evaluation of Dromedary Camel (Camelus dromedarius) Fetal Membranes

“…Contrariwise to what was observed in mares, avillous areas such as the cervical star or areas corresponding to oviductal papilla or the folding of the chorion around the allantoic vessels were not noticed. It is noteworthy that no areas without villi were found at the medial margins of the uterine horns, where the umbilical vessels run on the allantoic surface, as was instead reported in South American camelids by Meesters et al [16]. Sometimes, diffuse areas with more rarefied villi were observed at the tip of the uterine horns, confirming Morton's previous observations [13].…”

“…The amniotic plaques, observed also in equine [ 18 ] and Alpaca [ 16 ] placentas, are focal areas, scattered on the fetal side of the amniotic membrane, whose surface could become keratinized and appear as small horn-like rugose growths [ 13 , 18 ].…”

Determinación de algunas características biológicas de aislados primarios de células del corion de placenta de alpaca (Vicugna pacos)

“…A diferencia de las CpCPa analizadas de 20 células por cada pasaje, el incremento morfométrico evidencia mayor incremento en longitud y poco incremento en ancho celular. Si el peso promedio del corion de placenta de alpaca es de 0.5 ± 0.13 kg y la placenta total de 0.8 ± 0.19 kg (Meesters et al, 2019), los resultados de este trabajo podrían pronosticar un mayor número de células nucleadas, dentro de las cuales se encuentran las células madre, que según algunos autores pueden representar entre el 0.001 a 0.01% (Pittenger y Martin, 2004). Esto permitiría iniciar el aislamiento de células madre con un determinado peso de tejido placentario para obtener una suficiente población de estas células para su futura caracterización y expansión con fines terapéuticos.…”

Angioarquitectura macroscópica del complejo útero-fetoplacentario en alpacas (Vicugna pacos)

“…Todos los vasos (arterias y venas) presentes en la placenta, se encuentran anatómicamente debajo del corion. Por otro lado, en el borde anterior de ambos cuernos placentarios, se puede observar una franja libre de vellosidades coriónicas, denominada franja avillosa (Meesters et al, 2019), de aspecto liso, donde se ubican los vasos más grandes. Figura 3.…”

“…Hacia el borde anterior de la placenta, del segundo tercio en adelante, se observa una zona libre de vellosidades coriónicas, la franja avillosa (Meesters et al, 2019), que va desde la zona medial hasta el extremo de los cuernos uterinos, debajo de la cual se ubican los grandes vasos provenientes de las arterias y venas umbilicales. Ante esto, para una mejor descripción anatómica, se propone denominarlas arteria y vena placentaria izquierda y derecha, respectivamente (Figura 3D,E).…”