01431naa a2200145 a 450000100080000000500110000800800410001910000170006024500780007726000090015552010150016465000090117965000100118877300870119820923032018-06-07       1981    bl uuuu     u00u1 u    #d1 aMOORE, R. W.  aFertilisation rate of ewes mated to high and low prolificacy Romney rams.  c1981  aTen high prolificacy (.W) rams were compared with 10 low prolificacy (C) rams in their ability to fertilise randomly allocated Romney ewes. Ewes remained with the rams for a period of approximately 12 hours beginning 0 to 12 hours after the onset of oestrus. Mated ewes were killed 2 to 4 days later. Ewes from which only one cell ova were flushed were classified as unfertilised, while ewes with at least one cleaved ovum were classified as fertilised. The W rams fertilised 67% (29/43) of the single-ovulating ewes while the C rams fertilised 51% (25/49), and the W rams fertilised 87% (62/71) of the multiple-ovulating ewes while the C rams fertilised 65% (42/65). The W rams were more successful in fertilising both types of ewes  (59%) (P&lt0.05). Ten percent (8/78) of the fertilised twin-ovulating ewes where both ova were found had one fertilised and one unfertilised ovum (incomplete fertilisation): There was no difference between the two types of rams in the percentage of incomplete fertilisations.  aEwes  aSheep  tProceedings of the New Zealand Society of Animal Productiongv. 41, 224-228, 1981.