Fleece production patterns in Romney ewes: effects of
photoperiod, pregnancy and lactation
A.J. Pearson, P.E. Kendall, M.G. Ashby and J.E. Wildermoth
AgResearch Ruakura, Private Bag 3123, Hamilton, New Zealand.
Proceedings of the New Zealand Society of Animal Production. 1999, 59: 30-33
Twenty one Romney ewes were housed indoors for 12 months from
February to determine the effect of season, pregnancy and lactation on
wool growth. Ten ewes were naturally mated in April to lamb in
September. The ewes were fed to maintain constant maternal body weight
and a midside patch harvested monthly to determine clean fleece growth
rates. An effect of pregnancy on individual fibre length growth rate,
determined by autoradiography, occurred as early as 21-35 days after
joining. During the second month of gestation, fleece production and
mean fibre diameter fell below that of non-pregnant ewes and continued
to diverge until parturition. Wool production rose in the non-pregnant
group from August, but did not increase in lambing ewes until after
parturition. These data suggest that pregnancy is associated with an
early hormonally-mediated depression in follicle output superimposed on
the decline associated with winter photoperiod.
Keywords: NZSAPAB;
sheep; Romney; pregnancy; lactation; wool growth; nutrition;
hormones.
Last Updated 06-08-1999
