
%0 Journal Article
%A Blockey, MAde B 
%A Holst, PJ 
%A Makin, AW 
%A Cahill, LP 
%T Oestrus, ovulation and ovum transport in young Merino ewes
%J Australian Journal of Experimental Agriculture
%D 1979/04/01
%V 19
%N 97
%P 150-155
%K 
%R https://doi.org/10.1071/EA9790150
%U https://www.publish.csiro.au/paper/EA9790150 
%X Three groups of Merino ewes were studied to determine the effect of age of ewe (1 1/2 vs 2 1/2 years) and parity (0 vs 1) on the oestrus-ovulation relation and on the rate of ovum transport through the oviduct. Parity rather than age increased duration of oestrus from 11.6 hours in nulliparous I 1/2-year-olds to 17.4 hours in primiparous 2 1/2-year-old ewes (P < 0.01). As a result, 65% of primiparous ewes were still in oestrus by 15 hours before ovulation (the optimum time for conception) compared with 28.5% of the nulliparous ewes (P < 0.05). Ovum transport through the oviduct in the 48 hours after ovulation was similar in all groups. The study provides supportive evidence for the hypothesis that nulliparous 1 1/2-year-old ewes have higher ovum wastage than older, parous ewes because of their shorter duration of oestrus. 
