Arrested development of bovine Ostertagia spp. and Cooperia spp. in New Zealand. Effect of temperature and duration of storage on infective larvae.
Infective larvae of Ostertagia spp. and Cooperia spp. derived from naturally infected dairy calves were subjected to periods of storage of up to 16 weeks at 4 degrees C or 15 degrees C to determine if this treatment would influence their propensity for arrested development in previously worm-free calves. Results showed no significant increase in the propensity of Ostertagia spp. for arrested development in response to the treatments, but a small increase in the case of Cooperia spp.
Bisset
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Wallaceville Animal Research Centre, Research Division, Ministry of Agriculture and Fisheries, Private Bag, Upper Hutt, New Zealand.