STRATEGIC CONTROL OF GASTROINTESTINAL WOR MS - COMPARATIVE ADMINISTRATION OF IVERMECTINE AT TURN-OUT AND EITHER 6 OR 8 WEEKS LATER

In a herd of first-year grazing cattle two strategic programs for the control of gastrointestinal nematodes were compared, After allocating the animals to three groups of equal size one group was treated with i vermectin pour-on at turnout and six weeks later (0-6), a second group was also treated with ivermectin pour-on at turnout but 8 weeks later for the second time. The third group remained as untreated control, D ue to the hot and dry weather the pasture contamination was only moder ate, Comparing both control strategies no statistically significant di fferences could be found in faecal egg counts, pepsinogen concentratio ns, pasture larval counts or weight gains under the prevailing conditi ons.