Copper oxide needles administered during early pregnancy improve the copper status of ewes and their lambs

Abstract

AIM: To determine the effect of copper oxide (CVO) needles administered orally to ewes in early pregnancy on the copper (Cu) status of ewes throughout gestation and lactation, and of their lambs from birth to weaning.

METHODS: In mid-April, after mating, 12 twin-bearing ewes were given an oral capsule containing 5 g CuO needles while 12 others served as untreated controls. Changes in Cu status were monitored by determining serum and liver Cu concentrations on Days 1, 62, 117, 153, 185 and 216 in the ewes, and at 1, 36, 68 and 99 days of age for lambs. Pasture herbage samples were collected at about 60-day intervals for Cu, molybdenum (Mo), iron (Fe) and sulphur (S) determinations.

RESULTS: Copper status of the ewe flock was adequate, as initial mean serum and liver Cu concentrations were 15 μmol/L and 1,060 μmol/kg fresh tissue, respectively. The CuO needles did not affect serum Cu concentrations of the ewes or their lambs. Mean serum Cu concentration of all lambs at birth was about half that of ewes (8 vs 17 μmol/L), regardless of Cu supplementation, and not until at least 68 days of age was it similar to the dams'. Liver Cu concentrations of lambs at birth were also lower than that of the ewes (380 vs 640 μmol/kg fresh tissue among the controls), but changed little over time. CuO treatment increased liver Cu concentration in ewes for at least 185 days and in lambs for 36 days (p<0.05). Among untreated ewes, there was a seasonal decline in mean liver Cu concentrations, which were highest in autumn and lowest in early spring (1,060 vs 370 μmol/kg fresh tissue). The mean pasture mineral concentrations were Cu 5.7, Mo 0.48, Fe 194 and S 2,900 mg/kg dry matter (DM).

CONCLUSIONS: CuO needles administered to ewes in early pregnancy increased their Cu status through gestation and early lactation, and the Cu status of their lambs for 36 days from birth. Serum Cu concentration was not affected by treatment but a marked rise was observed in all lambs between birth and 10 weeks of age.

CLINICAL RELEVANCE: Copper deficiency in young lambs may be conveniently and effectively prevented by treating ewes with CuO needles during early pregnancy. The serum Cu concentration in lambs <8 weeks old may not reflect the Cu status of the flock.

KEY WORDS:

• Ewes
• lambs
• copper
• trace element
• supplementation
• serum
• liver
• copper status
• copper oxide needles

Acknowledgements

We are grateful to John Parr, Simon Green, Matthew Deighton and Peter Schreurs for technical assistance.