| Abstract | Thirty-six 6.5-month-old Alpine wethers (28±2.4 kg initial BW) were used to determine effects of Zelnate® (Z) and zoledronic acid (ZA) on immunity of goats infected with Haemonchus contortus during a 5-wk period. Wethers were housed in a confinement facility, supplemented with 400 g/d of a concentrate-based pellet, and offered alfalfa and grass hay free-choice. Thirty wethers were given 2 doses of 5,000 L3 H. contortus by gavage on 2 sequential days, and the other 6 were the noninfected normal control (NI-C). The infected control wethers (I-C) were not treated with Z or ZA. Other treatments were 1 injection of Z (2 ml/goat) on d -1 of L3 infection (Z1), 2 injections of Z on d -1 and 13 (Z2), 5 injections of ZA (75 µg/kg BW each time) on d -6, 2, 6, 13, 20 (ZA), and 1 injection of Z and 5 injections of ZA (Z1-ZA). Infection reduced ADG (P = 0.05), which was alleviated by Z and ZA (54, 14, 23, 23, 32, and 40 g for NI-C, I-C, Z1, Z2, ZA, and Z1-ZA, respectively; SEM=13.5). Although FEC was similar among treatments (P > 0.05), the percentage of female adult worms in the abomasum was lower in wethers treated with Z or ZA (P < 0.01). The hematocrit and concentrations of hemoglobin, WBC, and neutrophils were lower for I-C vs NI-C (P < 0.05) but concentrations of neutrophils for treatments with Z or ZA were similar to that for the NI-C. The percentage of female worms was negatively correlated with concentrations of neutrophils (r = -0.55, P < 0.01) and lymphocytes (r = -0.65, P < 0.01). The findings imply that H. contortus infection alters the immunity in goats and that effects may be reversed by immune modulators such as Z and ZA. |
