The passive transfer of immunoglobulins from colostrum is essential to protect neonatal lambs against infection until their own immune defense systems are fully developed. Adequate intakes of immunoglobulins must be achieved within the first 24h after birth because thereafter “gut closure” precludes any further antibody uptake. The degree of protection afforded is likely to be influenced by suckling frequency, colostrum intake and colostrum immunoglobulin concentrations. Two studies were therefore undertaken, the first to determine the extent of variation in colostrum IgG concentrations in a typical commercial flock of sheep, and the second to investigate the inter-relationships between suckling behaviour and IgG transfer in neonatal lambs.

Experiment 1. Colostrum samples were taken from both the left and right teats of 55 twin bearing Mule ewes immediately after lambing in January, and their IgG concentrations determined.

Experiment 2. The IgG content was measured in colostrum samples collected from both the left and right teats of 10 twin bearing Mule ewes immediately after lambing in March. In addition, a 10ml blood sample was also collected from the jugular vein of each lamb 36h after birth and subjected to IgG analysis.