Changes in the availability of dietary copper to young lambs associated with age and weaning

Abstract

SUMMARY64Cu and an indigestible 103Ru-labelled marker were administered into the alimentary tract of six artificially reared lambs on four occasions, 28 and 14 days before weaning and 15 and 42 days after weaning. The ratio of 64Cu: 103Ru excreted in the faeces was used to measure the apparent availability of Cu.Mean Cu availability decreased from 71·0 ± 3·7 to 47·2 ± 7·8% immediately before weaning and to 10·8 ± 1·4% 15 days after weaning.The relationship between availability (y, %) and age (x, days) prior to weaning was described by the equationWhen half of the lambs were given abomasal doses of 64Cu + 103Ru 42 days after weaning, the mean Cu availability was 21·4±4·0% compared with 3·7±2·1% for those dosed via the rumen.64Cu present in the whole plasma volume 20 h after dosing (y, % dose) was highly correlated with availability (x, %), the equation beingFour out of a group of eight milk-fed lambs were given access to a proprietary concentrate from birth and milk intake was progressively restricted so that by 15–21 days they were wholly dependent on the concentrate. Mean Cu availability at 23 days was 8·3±3·4% compared with 75·0±5·4% for lambs continuing to receive milk substitute alone. The corresponding values for 64Cu in plasma were 0·34±0·03 and 1·41±0·14% dose.Less than 1·1% of the 103Ru and 64Cu doses were excreted in the urine after 48 h and no 103Ru was detected in the plasma.The nutritional significance of and mechanisms for the reductions in Cu availability with age and weaning are discussed and methods for measuring Cu availability compared.

Trace Element Requirements, Diagnosis and Prevention of Deficiencies in Sheep and Cattle

“…During growth, pregnancy, and lactation, the demand for trace elements increases. The apparent absorption of trace elements in the suckling ruminant is greater than in the weaned or adult animal (Suttle 1975). mulation of the trace element (Bertinchamps et al 1966;Suttle et al 1982;Williams 1985).…”

Effect of copper supplementation on the copper status of pasture‐fed young Thoroughbreds

“…Many factors influence the effect of dietary copper intake on copper status in animals. Much of the work has involved ruminants and includes factors such as the post weaning development of the rumen (Suttle 1975) and mineral antagonists such as molybdenum, sulphur, iron and zinc, that affect copper absorption and metabolism (Gooneratne et al 1994;Suttle 1994). Less information is available for the horse, and differences in copper requirements for horses of different age, sex, breed and pregnancy status have not been well defined .…”

Effect of copper supplementation on copper status of pregnant mares and foals

“…The role of these liver copper stores at birth is uncertain. Copper absorption of young ruminants (Suttle 1975) and neonatal rats during ingestion of milk diets is very high due to the pinocytosis of copper complexes, which enables the resorption of copper excreted in the bile (Mistilis and Meanick 1969). Biliary excretion is also reduced in these animals, thereby enhancing copper conservation.…”