Effects of location and source of ewes and rams on the onset of
oestrus in Romney ewes
T.W. Knight, P.D. Muir, K.T. O'Neill, G.J. Wallace, G.J.
Hamilton, K. McLean
MAF Technology, Flock House Agricultural Centre, Private Bag,
Bulls, New Zealand
Proceedings of the New Zealand Society of Animal Production.
1992, 52: 207-210
Differences in onset of oestrus in Romney ewes has been observed
between locations at similar latitudes in the North Island. Two
experiments compared source of ewes and rams, and time of transfer of
ewes between locations on the onset of oestrus in Romney ewes. In Expt
1, groups of 30 ewes were interchanged between Wanganui and Takapau on
14 Nov, 5 Dec and 8 Jan. The next day these ewes plus 30 local ewes
were joined with 3 Poll Dorset rams. There were no effects of ewe
source but ewes at Takapau joined on 15 Nov, 6 Dec and 9 Jan had earlier
onsets-of-oestrus than ewes at Wanganui (P<0.05 to P<0.01). Ewes joined
on 15 Nov and 6 Dec at Wanganui had a later (P<0.01) onset of oestrus
than ewes joined on 9 Jan. In Expt 2, 60 ewes and 3 Poll Dorset rams
were interchanged between Wanganui and Poukawa on 13 Nov. These ewes
plus 60 local ewes were randomly divided in half and recombined to form
2 mixed groups which were joined with 3 Poukawa or 3 Wanganui Poll
Dorset rams. Onset of oestrus was earlier at Poukawa (P<0.001) and for
ewes joined with Wanganui rams (P<0.001) but there were no effects of
ewe source.
Keywords: NZSAPAB;
Oestrus; breeding season; teaser rams; Romney ewes; location;
ewe source.
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Last Updated 25-01-1997
