Proceedings of the 5th International Symposium on EQUINE ...

Havemeyer Foundation Monograph Series No. 3Experiment 3: The effect <strong>of</strong> temperature oncumulus morphologyCumulus oocyte complexes were recovered fromfollicles within 2 h <strong>of</strong> exteriorisation. The follicleshad been stored at 20–30ºC (n=34) and 35–37ºC(n=40).Experiment 4: The effect <strong>of</strong> time on cumulusmorphologyCumulus oocyte complexes (n=298) were left infollicles kept at 35–37ºC for varying lengths <strong>of</strong>time ranging from 0–1, 1–2, 2–3, 3–4, 4–6, 6–8and 8–10 h.STATISTICALANALYSISThe effects <strong>of</strong> temperature and time on oocytechromatin configuration and cumulus morphologywere analysed by a Chi-square test or a Fisher testin case <strong>of</strong> small sample numbers. The nullhypo<strong>the</strong>sis <strong>of</strong> <strong>the</strong> statistical test assumed that <strong>the</strong>rewas no difference. A P-value <strong>of</strong> 0.05 or less wasconsidered significant.RESULTSExperiment 1: The effect <strong>of</strong> temperature onchromatin configurationStoring ovaries at ei<strong>the</strong>r 20–30ºC or 35–37ºC didnot affect (P>0.05) chromatin configuration inoocytes that were fixed within 3 h <strong>of</strong> <strong>the</strong> ovaryleaving <strong>the</strong> animal. In <strong>the</strong> 20–30ºC group, 64.3%<strong>of</strong> oocytes were LCC and 35.7% were CC,whereas in <strong>the</strong> 35–37ºC group, 1.7% were FN,78% were LCC and 20.3% were CC.Experiment 2: The effect <strong>of</strong> time on chromatinconfigurationThere was no difference (P>0.1) in oocytechromatin configuration within <strong>the</strong> first 6 h <strong>of</strong>storage in <strong>the</strong> follicle. The configurations startedto change from 4 h onwards, but were notsignificantly affected until after 6 h. There was adifference in distribution <strong>of</strong> chromatinconfigurations between 0–6 and 6–12 h (P 0.1). The major changes between 0–6 h and6–12 h were detected in <strong>the</strong> FN configuration (P