Evaluating Amino Acid Profiles and Blood Gas Concentrations Between Single and Twin Merino Newborn Lambs

Abstract

As sheep production standards progress, and animals are bred for high production in terms of the number and weight of lambs weaned per ewe, research has identified a difference in the physiology of single lambs compared to multiple born lambs. The current study aimed to report the baseline amino acid (AA) profiles and blood gas concentrations in newborn, Merino single and twin lambs. From 120 days of gestation, 50 single-bearing and 50 twin-bearing, naturally mated Merino ewes were monitored for signs of approaching parturition. At birth, blood samples of the progeny were collected, and birth weight, rectal temperature, and meconium score were recorded. Blood plasma samples were analysed for AA profiles and blood gas concentrations were determined using an i-Stat Alinity. Single-born lambs had a higher birth weight (5.05 kg) compared to twins (4.24 kg; p < 0.05). Birth rank also affected rectal temperature and AAs aspartic acid, isoleucine, leucine, and phenylalanine, all being lower in twins compared to singles (p < 0.05). These baseline data provide insight into the physiological differences between single and twin lambs at birth from dams where there has been no treatment or intervention imposed.