Abstract

Triplet litter weight variation and association with lamb death and ewe age was investigated. Litter weight percentage for each lamb was calculated (PLWT). The mean and standard deviation of PLWT were used to rank lambs as Light (Mean + 1 SD). Average probability of viability at birth and death by dystocia or starvation exposure changed with weight rank. Viability at birth was Light 89.3%, Confidence interval (CI) 87.5% - 90.8%; Medium 95.6%, CI 95.1% - 96.1%; Heavy 98.0%, CI 97.4% - 98.5%, (P <0.001). Death due to dystocia was Light 8.9%, CI 7.2% - 10.8%; Medium 3.4%, CI 2.9% - 4.0%; Heavy 2.1%, CI 1.6% - 2.8%, (P <0.001). Death from starvation exposure was Light 5.9%, CI 4.8% - 7.4%; Medium 3.7%, CI 3.0% - 4.5%; Heavy 1.3%, CI 0.8% - 2.1%, (P <0.01). Ewe litter weight variation (EwePLVar) was calculated as weight range divided by total litter weight. Older ewes had less EwePLVar than two-year-old ewes (P <0.01). EwePLVar and average litter weight (AveLWT) affected litter survival (EwePLVar at birth, (P <0.001), birth to Day 3 (P <0.01). Average litter weight at birth (P <0.05), birth to Day 3 (P <0.01) and Day 3 to weaning (P <0.001)).

HC, Mathias-Davis, JV Yuan, and JM Everett-Hincks

Proceedings of the New Zealand Society of Animal Production, Volume 70, Palmerston North, 175-179, 2010