Observations on the free-living stages of cattle gastrointestinal Nematodes.

FIEL, C.A.; FERNÁNDEZ, A.S.; RODRÍGUEZ, E.M.; FUSÉ, L.A.; STEFFAN, P.E.

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2012 vol. 187 p. 217 - 226

0304-4017

A 4-year study on the free-living stages of cattle gastrointestinal nematodes was conductedto determine (a) the development time from egg to infective larvae (L3) inside the faecalpats, (b) the pasture infectivity levels over time, and (c) the survival of L3 on pasture.Naturally infected calves were allowed to contaminate 16 plots on monthly basis. Weeklymonitoring of eggs per gram of faeces (epg) values and faecal cultures from these animalsprovided data for the contamination patterns and the relative nematode population composition.At the same time, faecal pats were shaped and deposited monthly onto herbageand sampled weekly to determine the development time from egg to L3.Herbage samples were collected fortnightly over a 16-month period after deposition toevaluate the pasture larval infectivity and survival of L3 over time. The development timefrom egg to L3 was 1–2 weeks in summer, 3–5 weeks in autumn, 4–6 weeks in winter,and 1–4 weeks in spring. The levels of contamination and pasture infectivity showed aclear seasonality during autumn–winter and spring, whilst a high mortality of larvae onpasture occurred in summer. Ostertagia spp., Cooperia spp. and Trichostrongylus spp. werepredominant and a survival of L3 on pasture over a 1-year period was recorded in this study.