Variation and covariation in strongyle infection in East African shorthorn zebu calves
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Date
Authors
Callaby, R.
Hanotte, Olivier
Conradie van Wyk, Ilana
Kiara, Henry
Toye, Philip G.
Mbole-Kariuki, Mary Ndila
Jennings, Amy
Thumbi, Samuel Mwangi
Coetzer, Jacobus A.W.
Bronsvoort, Barend Mark de Clare
Journal Title
Journal ISSN
Volume Title
Publisher
Cambridge University Press
Abstract
Parasite burden varies widely between individuals within a population, and can covary with multiple aspects of individual
phenotype. Here we investigate the sources of variation in faecal strongyle eggs counts, and its association with body weight
and a suite of haematological measures, in a cohort of indigenous zebu calves inWestern Kenya, using relatedness matrices
reconstructed from single nucleotide polymorphism (SNP) genotypes. Strongyle egg count was heritable (h2 = 23·9%,
S.E. = 11·8%) and we also found heritability of white blood cell counts (WBC) (h2 = 27·6%, S.E. = 10·6%). All the traits
investigated showed negative phenotypic covariances with strongyle egg count throughout the first year: high worm counts
were associated with low values of WBC, red blood cell count, total serum protein and absolute eosinophil count.
Furthermore, calf body weight at 1 week old was a significant predictor of strongyle EPG at 16–51 weeks, with smaller calves
having a higher strongyle egg count later in life. Our results indicate a genetic basis to strongyle EPG in this population, and
also reveal consistently strong negative associations between strongyle infection and other important aspects of the
multivariate phenotype.
Description
Keywords
Gastrointestinal parasites, Strongyle, Indigenous cattle, Kenya, Heritability, Haematology, Parasite infection, East African short-horn zebus
Sustainable Development Goals
Citation
Callaby, R, Hanotte, O, Conradie Van Wyk, I, Kiara, H, Toye, P, Mbole-Kariuki, MN, Jennings, A, Thumbi, SM, Coetzer, JAW, Bronsvoort, BMDC, Knott, SA, Woolhouse, MEJ & Kruuk, LEB 2015, 'Variation and covariation in strongyle infection in East African shorthorn zebu calves', Parasitology, vol. 142, no. 3, pp. 499-511.