EFFECT OF AGE AND PARITY ON MATERNAL-BEHAVIOR IN SINGLE-BEARING MERINO EWES

Behavioural factors associated with lamb mortality were examined in regard to the relative effects of age and parity in single-bearing Merino ewes. Primiparas tended to have longer labour and higher lamb mortality than multiparous ewes. Maternal behaviour in primiparas was characterised by more desertions, a smaller proportion that stood and started to groom their lambs immediately after birth, and a larger proportion with non-cooperative behaviour during the initial sucking attempts of the lamb. These traits, and a high incidence of malpresentations, were particularly marked in 5-year-old primiparas deliberately denied access to rams in previous seasons. There was no evidence of improved maternal behavioural attributes associated with increasing age of ewe that were independent of previous experience in giving birth and rearing lambs.