Comparison of the behaviour of Romney and Merino ewes lambing on slopes

Abstract

Observations were made over 2 years on 27 single-bearing Merino ewes and 26 single- and nine twin-bearing Romney ewes lambing on paddocks with slopes of 33-44°. In 1989, lambing was induced by injecting 15 mg of dexamethasone on Days 140—142 in Romney ewes and on Days 143—145 in Merino ewes. There were no differences between Merino and Romney ewes in the incidence of lambs slipping off the birth site or in the ability of the two breeds of ewes to follow lambs down the slope. More Merino than Romney ewes lambed in the top third of the slope in each paddock (92 versus 60%). Following the injection of 15 mg of dexamethasone, the interval to lambing was longer in Merino than Romney ewes and there tended to be a greater spread of lambing in the Merinos.

Keywords:

• birth sites
• lambing
• behaviour
• Romney
• Merino
• ewes
• paddock slopes
• sheep