The objective of this experiment was to study colostrum yields and immunoglobulin (Ig) concentrations and subsequent calf serum Ig concentrations using mature suckler cows adequately fed pre-partum or severely feed restricted for the last 2 weeks of preganancy and 2 year old replacements heifers.

Cows from a Limousin x Friesian spring calving suckler herd were used. There were 3 treatments 1) cows adequately fed pre-partum (second cut grass silage) (n=12) 2) , cows severely feed restricted for 2 weeks pre-partum (straw diet) (n=6) and, 3) two year old heifers calving for the first time and adequately fed (n=6). All animals were offered a suitable mineral/vitamin supplement. Colostrum yield was obtained by hand milking half the udder following an intramuscular oxytocin injection. Colostrum was then sampled. The objective was to feed the calf an allowance of 50g of colostrum /kg bodyweight via stomach tube. Actual colostrum intakes (g/kg bodyweight ± S.E.) were 47 ± 1.4, 48 ± 2.3 and 46 ± 1.9 for treatments 1, 2 and 3, respectively. Following an eight hour period when the calf was prevented from suckling (but left in the presence of the dam) a colostrum sample was obtained (2nd milking), the calf was blood sampled and then allowed to suckle as normal.