No abstract

ContentsIn multiple ovulation and embryo transfer (MOET) programmes in cattle, a considerable number of morphologically poor-quality embryos continue to be produced; this is one of the limiting factors of the technique. Apoptosis has often been implicated in developmental arrest and fragmentation; these are regarded as poor traits of embryonic quality in mammalian pre-implantation embryos. In the present study, apoptosis was assessed in morphologically poor-quality embryos in comparison with good-quality embryos that were recovered from a MOET programme. Retarded embryos (two to 16 cell stage), morulae with severe fragmentation and morphologically goodquality morulae recovered from superstimulated cows at day 7 post-insemination were subjected to TdT-mediated dUTP nick-end labelling (TUNEL) and Hoechst staining. Cell nuclei that showed both TUNEL staining and apoptotic morphology were considered to be apoptotic. Apoptotic index (AI) was calculated as the percentage of apoptotic cells per embryo. Fifteen of 17 retarded embryos and 10 of 15 morphologically poor-quality morulae did not show signs of apoptosis. The mean AIs in the morphologically poor-quality embryos (two to 16 cell stage, 2.2%; poor morulae, 1.3%) were as low as that in the good-quality embryos (2.9%). These results suggest that another mode of developmental arrest and/or fragmentation that is independent of apoptosis occurs in morphologically poor-quality embryos recovered from MOET programmes.

Using cardiotocogram and umbilical arterial gas analysis, the presence or absence and variations of umbilical cord coiling were examined with relation to the incidence of variable deceleration (V.D.) and neonatal asphyxia. The results obtained were as follows. 1) The incidence of V.D. with cord coiling was higher than that without cord coiling (p less than 0.005). The incidence of severe V.D. with cord coiling was also higher than that without cord coiling (p less than 0.005). 2) The mean Apgar scores of cases with cord coiling were lower than that without cord coiling (p less than 0.02). 3) On the umbilical arterial gas analysis, the mean pH of cases with cord coiling was lower than that without cord coiling (p less than 0.05). And the mean pCO2 of cases with cord coiling was higher than that without cord coiling (p less than 0.005). So neonate with cord coiling showed a tendency towards respiratory acidosis in comparison with that without cord coiling. 4) The incidence of neonatal asphyxia with cord coiling was 16.0% (Apgar score less than or equal to 7), 20.0% (pH less than 7.20) and that without cord coiling was 8.8%, 13.2%, respectively. Although there was no statistically significant difference, a tendency was observed towards a higher rate of neonatal asphyxia with cord coiling. 5) The incidence of neonatal asphyxia with severe V.D. was 44.4% (Apgar score less than or equal to 7), 36.1% (pH less than 7.20) and that without severe V.D. was 5.7%, 8.6%, respectively. There was a statistically significant difference (p less than 0.005, p less than 0.005). In addition, the incidence of neonatal asphyxia with repeated V.D. was 35.3% (Apgar score less than or equal to 7), 44.1% (pH less than 7.20) and without repeated V.D. was 3.8%, 6.5%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)