Biological control of nematode parasites of livestock in Fiji: screening of fresh dung of small ruminants for the presence of nematophagous fungi.

Approximately 2500 faecal samples were collected per rectum from sheep and goats from 26 farms located on four of the Fijian islands where most of the small ruminants in this country are raised. The purpose was to screen these samples to isolate nematode-trapping fungi that had been acquired by these animals during the course of their feeding and which had remained viable following passage through their gastrointestinal tract. From these samples, 23 examples of nematophagous fungi were noted in the initial appraisal, from which 12 pure isolates (all of the genus Arthrobotrys) were made. A number factors emerged from this work which may have restricted the opportunities in which nematophagous fungi were detected, or isolated.

The value of circulating eosinophil count as a selection criteria for resistance of sheep to trichostrongyle parasites.

In merino sheep bred for either increased or decreased resistance to Haemonchus contortus, faecal worm egg counts (FEC) were lower in the resistant line (6,831 vs 17,645 epg, P < 0.01), and circulating eosinophils (EOS) were higher, but not significantly so (3.40 x 10(4) ml(-1) vs 1.40 x 10(4) ml(-1), P = 0.1 1). Another flock was artificially infected with Trichostrongylus colubriformis and significant genetic variation was found in both FEC (heritability 0.40 +/- 0.11) and EOS (0.19 +/- 0.08). In a third flock comprising tropical sheep breeds, a natural challenge with T. colubriformis resulted in significant sire effects on FEC (heritability 0.20 +/- 0.10) but not EOS (heritability inestimable). We conclude that EOS offers no advantage over FEC as it selection criterion for resistance.