Establishment of camel isolates of Haemonchus longistipes and Trichostrongylus colubriformis in goats.

Two main nematode parasites, Haemonchus longistipes and Trichostrongylus colubriformis, have been reported to cause morbidity and mortality in camels. Although goats are usually reared with camels in the combined animal husbandry system prevailing in Northern India, these parasites have not been reported in goats. Therefore, it was planned to conduct an experimental cross-transmission study of H. longistipes and T. colubriformis isolated from camels and transferred to young goats. Twelve healthy kids (5-6 months) were divided into three groups of four each. Groups I and II were infected orally with third stage infective larvae of H. longistipes and T. colubriformis cultured in the laboratory from faecal isolates from camels, at the rate of 50,000 and 100,000 larvae, respectively; group III comprised uninfected healthy controls. Daily clinical and faecal examinations were made. Body weights and blood haematological indices were measured at weekly intervals. The infection became established in both infected groups, and the animals started passing ova 17 days postinfection. Egg counts varied from 275.00 +/- 248.74 to 6150 +/- 2830.63 eggs g-1. Animals were killed 28 days postinfection. On postmortem examination mature as well as immature worms were recovered from the abomasum and intestine with typical postmortem changes seen in both the groups. Clinical manifestations were weakness and loss of body weight but no diarrhoea. There was a marked fall in haemoglobin and packed cell volume, indicating anaemia in both infected groups.

Comparative effects of nematode infection on Bos taurus and Bos indicus crossbred calves grazing on Argentina's Western Pampas.

Breed differences in resistance or tolerance to naturally acquired gastrointestinal nematodes were compared between Aberdeen Angus (AA) and Santa Gertrudis (SG) weaned steer calves grazing in a temperate environment. Within breeds, one half of the calves was untreated: AAU (n = 17) and SGU (n = 18) while the other half was treated with moxidectin monthly: AAT (n = 14) and SGT (n = 14). All calves were grazed on the same contaminated pasture from autumn to winter, when each group was separated to uninfected paddocks for the remaining period of the study. Faecal egg counts, plasma pepsinogen levels (PPL), herbage larval counts and liveweight (LW) were recorded monthly. Egg counts and PPL of AAU and SGU increased from autumn to early winter when calves showed heavy parasitism (mainly Trichostrongylus axei) and severely sick calves needed emergency treatment. On the clean paddocks, parasitological parameters progressively decreased. Late winter egg counts were higher (P < 0.05) in SGU than in AAU. PPL of SGU were higher than AAU ones, but no significant differences were detected. Larval differential counts of SGU showed fewer Cooperia (P < 0.08) and higher T. axei (P < 0.002) proportions than those of AAU. Numbers of severely sick and dead SGU calves (61%) were greater (P < 0.01) than those numbers of AAU calves (17.5%). Cumulative LW gains differences within SG breed were higher (P < 0.0001) than those differences within AA breed (P < 0.003). LW gains of AAU during autumn-winter period were greater (P < 0.002) than those of SGU.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of morphological changes and ileal glucagon gene expression in the small intestine of lambs infected with Trichostrongylus colubriformis.

To investigate the consequences of subclinical Trichostrongylus colubriformis infection on the intestinal mucosa and the associated changes in entero-glucagon gene expression, sheep were infected with 30000 larvae and killed 5, 10, 15 or 20 days after infection. Histological and cytological changes were examined. In the main site of infection, the upper duodenum, villous atrophy associated with crypt hyperplasia developed gradually. Cytological changes in the enterocytes appeared concurrently, characterized by a progressive reduction in brush border and in the number of ribosomes in the cytoplasm, changes in the internal structure of mitochondria, and enlargement of the intercellular spaces. Neither histological nor cytological modifications were found before day 15. At the same time, villous hypertrophy developed distally, beyond the main site of infection; this was interpreted as an adaptive response to parasitism. Enteroglucagon gene expression in the ileum was measured in parallel with the mucosal changes but did not reveal any difference between infected and control sheep. The results indicate that this gastrointestinal hormone does not have a major role in the response to nematode parasitism.

Sewage sludge or cattle slurry as pasture fertilisers: comparative cysticercosis and trichostrongylosis risk for grazing cattle.

Sewage sludge and slurry are used as fertilisers on pastures grazed by ruminants. The former may be a source of Taenia saginata, which causes cysticercosis in cattle and taeniosis in man. The latter is a source of digestive tract-strongyles, a major helminth infection in cattle. The interest of application on pastures of these two biowastes is environmental (optimal recycling of biowastes) and agronomic (fertilisation). The parasitic risk and the fertilisation value of such applications on pastures were evaluated during one grazing season. Liquid sewage sludge did induce higher herbage biomass, which corresponded to higher liveweight gains during the first 2 months of grazing, compared to slurry spread pastures and calves grazing them. The sludge group of calves did not acquire live cysticerci and thus the risk was nil under the conditions of the study (delay of 6 weeks between application and grazing). The slurry group of calves did become lightly infected with digestive-tract strongyles, mostly Ostertagia ostertagi. Under the conditions of this experiment, a 6-week delay between application and grazing strongly reduced the risk of infection: it renders compatible the agronomic use and requirements of public or animal health.