Nematodirus

Rijal, Samridhi, Neuhaus, Peter, Thorley, Jack, Caulkett, Nigel, Kutz, Susan & Ruckstuhl, Kathreen E., 2024, Patterns of gastrointestinal parasite infections in bighorn sheep, Ovis canadensis, with respect to host sex and seasonality, International Journal for Parasitology: Parasites and Wildlife 24, pp. 100950-100950 : 100950-

3.2. Nematodirus

Season and sex significantly affected Nematodirus fecal egg counts in an interaction (X 2 = 28.44, df = 3, p <0.001), while age had no effect (X 2 = 0.11, df = 1, p = 0.74; Table 2).

In females the Nematodirus fecal egg counts were highest during the late gestation/spring season and significantly lower during the rutting and winter ( Fig. 2b –Appendix A2). Males seemed to shed the highest number of eggs during the rut and the lowest during the late gestation season, but none of these means were signficantly different ( Fig. 2b –Appendix A2). There were signficant differences in Nematodirus counts between the sexes in the late gestation and rut season: while females had significantly higher counts in late gestation, males had significantly higher counts of Nematodirus during the rutting season ( Fig. 2b –Appendix A2).

The mating tactic males employed during the rut did not affect their fecal Nematodirus egg count (Estimate = – 0.13, SE = 0.26, X 2 = 0.24, df = 1, p = 0.63).

Figures

Fig. 2. Seasonal differences in fecal egg counts in female (blue) and male (red) bighorn sheep. Point intervals display the mean count ±95% confidence intervals as predicted by generalised linear mixed effects models. Seasons are: Late gestation (Late gestation/early lactation between April to June); Lactation/summer (between July and October); Rut (November and December); Winter (Winter/early gestation from January to March). Parasites are a) Strongyle; b) Nematodirus; c) Marshallagia; d) Protostrongylus lungworm; e) Eimeria. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)