An evaluation of copper-containing soluble glass pellets, copper oxide particles and injectable copper as supplements for cattle and sheep

Abstract

The efficacy of 3 copper (Cu) supplements in maintaining adequate Cu status in Shorthorn heifers and Merino wethers was investigated in 3 experiments on alkaline peat soils in the South East of South Australia. The Cu supplements used were: soluble glass pellets containing Cu; copper oxide particles (CuO); Cu as a subcutaneous injection. Pasture contained moderate to high concentrations of molybdenum (Mo) (2.9-12.3 mg/kg), moderate Cu (3.8-8.7 mg/kg) and adequate sulfur (>1.7 g/kg) to limit the absorption of dietary Cu in ruminants. Shorthom heifers with normal Cu status were given 1 of 6 treatments (no Cu; 2 glass pellets; CuO at 3 doses; Cu injection) and introduced to the pasture (experiment 1). There was no liveweight response to any supplement. Relative to untreated heifers, mean liver Cu concentrations were raised only in heifers receiving the glass pellets or the highest dosage of CuO (20 g). The glass pellets maintained an adequate mean liver Cu concentration for at least 44 weeks but the CuO was effective for less than 24 weeks. Hypocupraemic heifers given 1 of 3 treatments (2 glass pellets; CuO; Cu injection) were significantly heavier (P<0.05) than the untreated heifers after 30 weeks (experiment 2). Mean plasma Cu concentrations were adequate at 30 weeks in the glass pellet and CuO groups, but mean liver concentrations indicated severe deficiency in all groups at 30 weeks. There was considerable individual variability in response to the glass pellet and CuO particle treatments, possibly due to the partial regurgitation of some of these orally dosed supplements. Merino wethers with adequate plasma and liver Cu concentrations received 1 of 5 treatments (no Cu; 1 glass pellet; 2 glass pellets; CuO; Cu injection) and were then grazed on a peat soil for a period of 1 year. Plasma Cu concentrations in the control group only indicated hypocupraemia at week 42. Liver Cu concentrations were higher (P<0.001) in all supplemented groups from week 18 to after week 30. Under the conditions of the experiments, 20 g CuO (the suggested dose) for the glass pellets or a single Cu injection were not sufficient to maintain the Cu status of heifers for 1 year. Repeat treatments or higher dose rates were required. The recommended dose rates of the supplements were adequate for wethers.

Comparison of copper heptonate with copper oxide wire particles as copper supplements for sheep on pasture of high molybdenum content

“…The high Mo values are similar to those values observed in pasture where livestock are at risk from Cu deficiency 4,5. …”

“…These doses of COWP raised liver copper reserves above those of untreated sheep for 6 to 9 months in adults and 5 to 6 months in weaners, periods that are slightly less than the 8 to 12 months reported. 5,16,17 Copper values above 0.3 mmol/kg DM in liver and 9 µmol/L in plasma are usually indicative of Cu adequacy in sheep. 18 Mean Cu values in our adult wethers were above these limits at all times apart from the last sampling on day 351, when plasma TCA-soluble Cu was marginal ( Table 3) and was associated with a depressed body weight.…”

Accumulation and depletion of liver copper stores in dairy cows challenged with a Cu-deficient diet and oral and injectable forms of Cu supplementation

“…Supplements have previously been evaluated in cattle with low initial concentrations of Cu in liver (range 130-275 μmol/kg fresh tissue) (Richards et al 1985;Wittenberg et al 1990;Muehlenbein et al 2001). However, in at least four published studies, the cattle had concentrations of Cu in liver of 650-1,000 μmol/kg fresh tissue, the basal diet was Cudefi cient, and the Cu status of the control cows decreased during the trial (Rogers and Poole 1988;McFarlane et al 1991;West and Sargison 1998;Bailey et al 2001). Similarly, the conditions in the study presented here provided a suitable model to assess and compare Cu supplements under the challenge of Cu-defi cient intake.…”

Mineral Supplementation

“…Single oral doses of the particles raise liver Cu reserves of sheep for 6 to 12 months even when sheep are on diets of moderately high Mo and S content (McFarlane et al, 1991).…”