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Changes in the hatch rate of Haemonchus contortus eggs between geographic regions

Published online by Cambridge University Press:  06 April 2009

L. F. Le Jambre
Affiliation:
New York State College of Veterinary Medicine, Cornell University, Ithaca, N.Y. 14853, U.S.A.
J. H. Whitlock
Affiliation:
New York State College of Veterinary Medicine, Cornell University, Ithaca, N.Y. 14853, U.S.A.

Extract

Vulvar phenotypes and the rate of development of eggs over a range of temperatures were used to compare Haemonchus contortus populations in New York State and Ohio. These parameters indicated that the westernmost boundary of the subspecies Haemonchus contortus cayugensis is the Chautauqua valley in New York. The Haemonchus ecotype in Ohio had a vulvar phenotype formula similar to that described for the subspecies Haemonchus contortus contortus. The relationship between slope and intercept of the regression of rate of egg hatch on temperature was different for morphs within ecotypes as well as between the New York and Ohio ecotypes. Linguiform-A appeared to be the cold-adapted morph in both ecotypes. Smooth was the warm-adapted morph in New York with linguiform-B filling that niche in Ohio.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1976

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