Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2004
Publication Date: 8/1/2004
Citation: Burke, J.M., Miller, J.E., Olcott, D. 2004. Effect of copper oxide wire particles dosage and feed supplement level influences Hemonchus concortus infection in lambs. Veterinary Parasitology. 123/3-4:235-243. Interpretive Summary: The effectiveness of current anthelmintics in sheep and goats is decreasing as many internal parasites become drug resistant, and thus, other means of control need to be developed. The objective of the experiment was to determine the optimal dose of cooper oxide wire particles bolus to reduce infection of H. contortus in lambs. The numbers of H. contortus internal parasites were greatly reduced in all animals receiving the copper wire. These results demonstrate the effectiveness of copper wire to control an economically important parasite of sheep and goats, and are of interest to small ruminant producers in the southeast United States and agricultural professional who work with them.
Technical Abstract: The objective of the experiment was to determine the optimal dose of COWP to reduce infection of H. contortus in male lambs. Lambs used were 5 to 6 months old Katahdin (n = 15), Dorper (n = 16), and Dorper crossbred (n = 19), housed on concrete and fed 454 (L; n = 25) or 680 g (H; n = 25) corn/SBM supplement with free choice access to bermudagrass hay, trace mineral and water. In July, lambs were inoculated with 10,000 L3 larvae (97% H. contortus; Day 0). Blood and feces were collected every 7 d for determination of packed cell volume (PCV) and fecal egg counts (FEC) between Day 0 and day of slaughter or Day 54 (n = 25) or 63 (n = 24). Lambs were administered 0, 2, 4, or 6 g COWP on Day 28. Concentrations of copper in the liver were determined. One of the control lambs died on Day 37, likely from haemonchosis. There were no effects of supplement level on concentrations of copper in the liver and a linear relationship existed between COWP treatment and concentrations of copper in liver (y = 74.6 + 22.8x, where y = liver concentrations, ppm and x = COWP dose; P < 0.001). LS means of the 0, 2, 4, 6 g COWP treatments were 62.2, 135.7, 161.1, and 208.4 ± 13.8 ppm (P < 0.001). Between Days 0 and 28, PCV declined in all groups of lambs by nearly 8 percentage units and by Day 42, PCV of all COWP treated lambs was markedly higher than control lambs and remained higher (COWP x day, P < 0.05). By Day 21, PCV was greater in the H compared with the L group of lambs (P < 0.001) and, with the exception of Day 42, remained higher in these lambs (supplement x day, P < 0.001). The increase in FEC in response to inoculation was observed by Day 21 in all lambs. Within 7 days of COWP treatment FEC declined from more than 8,000 eggs/g (epg) to less than 1,000 epg in all COWP treated lambs (COWP x day, P < 0.001). FEC were similar between the 4 and 6 COWP lambs at all times, but FEC were greater on Day 35 in the 2 g (830 epg) vs. 4 and 6 g (75, 72 epg) COWP group (P < 0.02). The numbers of H. contortus in the abomasum were greatly reduced in all COWP treated groups of lambs and remaining nematodes were primarily males. FEC were greater in L vs. H supplemented lambs and values decreased to a greater extent in H lambs when treated with COWP (supplement x COWP; P < 0.02). The 2 g COWP was effective in alleviating H. contortus infection and reducing number of egg-laying nematodes in the abomasum with the lowest concentration of copper in the liver of the COWP treatment groups. PCV values were more favorable for lambs fed the higher level of supplement, especially when FEC were greater than 8,000 epg.