Abstract

This study attempted to identify physical and physiological factors of twin- and triplet born lambs within the first 24 to 36 hours of life which are associated with maximum heat production on a per lamb basis (W/lamb) and a per kg of birth weight basis (W/kg). Multiple regression analyses revealed that lamb birth weight accounted for 34 percent of the variation in maximum heat production on a per lamb basis (P <0.001), whereas, inclusion of plasma non-esterified fatty acids (NEFA; P <0.01), tri-iodothyronine (T3; P <0.05) and glucose concentrations at 24 to 36 hours of age (P <0.05) increased the accountability to 59 percent. Multiple regression analyses also revealed that plasma NEFA concentrations at 24 to 36 hours of age accounted for 15 percent of the variation in maximum heat production on a per kg of birth weight basis (P <0.01), whereas, inclusion of plasma T3 at 24 to 36 hours of age increased the accountability to 22 percent (P <0.05). Overall these results suggest that having greater lamb birth weights, plasma thyroid hormone, glucose and NEFA concentrations at 24 to 36 hours of age is beneficial for twin- and triplet-born lamb thermoregulation during periods of cold stress.

JI, Kerslake, PR Kenyon, ST Morris, KJ Stafford, and PCH Morel

Proceedings of the New Zealand Society of Animal Production, Volume 71, Invercargill, 286-290, 2011