The use of a gamma-type function to assess the relationship between the number of adult Teladorsagia circumcincta and total egg output

SC Bishop, MJ Stear

Research output: Contribution to journalArticlepeer-review

Abstract

The relationship between faecal nematode egg count and the number of adult Telordasagia circumcincta was examined in 508 naturally infected lambs at 6-7 months of age. The relationship was found to be convex and was empirically described by a gamma-type function of the form y = an(b) e(-cn), where n is the number of adult nematodes present and y is the number of nematode eggs per gramme (epg) of faeces. This equation predicted that the peak expected egg count (277 epg) would occur at a worm burden of 2167 adult worms. The absence of a linear relationship between egg counts and worm numbers is consistent with the existence of severe density-dependent constraints on the fecundity of T. circumcincta.

Original languageEnglish
Pages (from-to)435-440
Number of pages6
JournalParasitology
Volume121
Publication statusPublished - Oct 2000

Keywords

  • Teladorsagia circumcincta
  • nematode
  • sheep
  • fecundity
  • density dependence
  • OSTERTAGIA-CIRCUMCINCTA
  • UNGULATE POPULATION
  • INFECTION
  • COUNTS
  • LAMBS
  • RESISTANCE
  • FECUNDITY

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