Review/Oorsig Volume 22, Issue 04 - Page 8

Oorsig/Review There is almost equal patchy involvement of cotyledonary and inter-cotyledonary areas (figure 12). Placental pathology is characterised by soft thickening of the periphery of cotyledons (necrosis) with adherent cheese-like debris and in some instances haemorrhage (vasculitis). Marked edema and opacity of the adjacent inter- cotyledonary areas accompany the cotyledonary changes (figure 13). Frequently only placental pathology is evident in the abcscence of any fetal pathology. *Pathology presentation is equal cotyledonary and inter-cotyledonary. Toxoplasmosis Fetal mass: The mass of a foetus is a further parameter which can be used to assess fetal age. It is important to remove all fetal membranes and transect the umbilical cord at the level of the umbilicus, before the carcass is weighed. Factors affecting birth weight in sheep include: • • • • Litter size Sex of lamb Maternal body composition prior pregnancy Maternal nutrition during late gestation to Crown-rump length: An accurate crown-rump length measurement is statistically very closely correlated to actual foetal age. Scan to view video Figure 14 - miliary pin-point necrosis of placental cotyledons (toxoplasmosis) Metacarpal bone length : thickness ratio: This is a useful method to distinguish between chondrodysplastic dwarfs, in-utero growth retarded (IUGR) fetuses and normally developed fetuses, as in true chondrodysplastic dwarfs the distal limb bones are proportionately shorter than proximal bones, with the metacarpi showing Toxoplasma gondii placental pathology is of multifocal cotyledonary necrosis and intercotyledonary oedema. These lesions are striking and pathognomonic for toxoplasmosis. *Pathology presentation is exclusively cotyledonary. MORPHOMETRIC MEASUREMENTS Scan to view video Fetal weight, birth weight and crown-rump length are strongly correlated to foetal age in domestic species (b F'V֖BBv7G&72f FW7F2'V֖G2FW&R&R6V"BvVЦFVfVB&WFW'2f"FRW7FFbfWFvR&6VBfWF&GvVvG2B7&v'VVwF2ࣀfwW&RR&fRfWGW2r&RvFw&wF'&W7BƖW0'&rFRw&VFW7BFVw&VRb6'FVrG'VRGv&g0F2&F2RvR&F2bBR&R66FW&V@&Tu"fR&F2b2RBRw&wF'&W7BƖW2r&W3FW6RW60FWfV266WVV6Rb7F7F'Bw&wFGVRF6RWFW&6FVBvWFW"FB&PfV7FW2"֖fV7FW2FB7F2FRw&wFbFRfWGW2&fRf&F'&Vf'W27GVǐfV7G27FV67G2FFrw&wF'&W7B@w&wFFR&&ƗFW2