Variation and covariation in strongyle infection in East African shorthorn zebu calves.

Rebecca Callaby, O. Hanotte, Ilana Conradie van Wyk, Henry Kiara, Phil Toye, Mary Ndila Mbole-Kariuki, Amy Jennings, Samuel M Thumbi, J A W Coetzer, Mark Bronsvoort, Sara Knott, Mark Woolhouse, Loeske Kruuk

Research output: Contribution to journalArticlepeer-review


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 in Western Kenya, using relatedness matrices reconstructed from single nucleotide polymorphism (SNP) genotypes. Strongyle egg count was heritable (h 2 = 23·9%, s.e. = 11·8%) and we also found heritability of white blood cell counts (WBC) (h 2 = 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.
Original languageEnglish
Pages (from-to)499-511
Number of pages13
Issue number3
Early online date26 Sep 2014
Publication statusPublished - Mar 2015


  • gastrointestinal parasite infection
  • haematology
  • heritability
  • indigenous cattle
  • Kenya
  • strongyle


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