Intake of trichostrongylid larvae by goats and sheep grazing together

SUMMARY Cashmere goats and Merino sheep were grazed together at 7.5 animals per ha on annual rye grass and clover pasture in southern Victoria, a winter rainfall area. Intake of parasitic larvae was measured in oesophageal extrusa samples collected from 2 animals of each species, 4 times in one week, on 7 occasions between mid-March (autumn) and mid-June (winter). Pasture contamination with larvae was measured at the same times. The number of larvae per kg of green grass was lower than on green clover; the most heavily contaminated portion of the pasture was the mat of dead herbage on the ground. The diet selected by goats contained more green grass and dead herbage and less clover that that of sheep (P < 0.01). Goats ingested 643 infective trichostrongylid larvae per kg dry matter intake (DMI) versus 274 per kg DMI for sheep in autumn, increasing to 1892 versus 1143 in early winter. The heavier trichostrongylid burdens of goats compared with sheep, when grazed together, are due in part to greater rates of infection consequent on different grazing patterns as well as greater susceptibility to infection.     

The trichostrongylid egg output during spring in feedlot cattle

Larval cultures prepared from faeces collected at two-week intervals from feeder cattle originating from Michigan, Oklahoma and Kentucky, and kept in a feedlot in Michigan, were examined during the winter and spring of 1979. The animals received anthelmintic treatment shortly after entering the feedlot. The larval output, consisting mainly of Ostertagia larvae, was less than 20 larvae per g, but did show a seasonal increase during spring in the cattle originating from Kentucky and Michigan. This "spring rise" was not observed in the animals originating from Oklahoma which is thought to be related to a difference in transmission pattern of Ostertagia in the southwest as compared to the eastern and midwestern parts of the U.S.A.     

Influence of transport stress on trichostrongylid infection in feedlot beef cattle

The influence of stresses due to transport of beef cattle and their allotment to feedlots on trichostrongylid infection was studied. The greatest increases in worm egg counts and serum pepsinogen levels were seen at 5 h and 30 days after allotment. These apparently resulted from reactivation of arrested larvae which the animals ingested while grazing during late autumn at the breeding farm.     

Epidemiological investigations of trichostrongylid infections in young cattle in different parts of Norway

The occurrence of trichostrongylid nematodes in young cattle was studied in relation to climate and geographical location, by examination of herbage and faecal samples from 8 farms in 7 different regions in Norway, during 3 consecutive summers. Species of Ostertagia and Cooperia were dominant. Infective larvae, especially those of Ostertagia, were able to survive the winter in the pasture to a great extent in all the areas studied. The spring larval counts varied considerably from place to place, and from year to year, but were often at fairly high levels. This confirms previous findings that the larvae which overwinter on the pasture may be a major cause of losses. Overt clinical disease, however, was only seen at 1 farm during this investigation.The large number of larvae often seen in the autumn seems to be of less significance as a cause of disease, due to the late appearance, but is of major importance as a source of the larvae which survive the winter in the pasture and infect young cattle the following spring.There was no obvious correlation between pasture larval counts and the climate, except that there seemed to be higher counts in the warmer parts of the country, where the grazing season is also longer. The only place were both faecal egg counts and larval counts in the herbage were consistently low, was in the very far north.     

Nitrate poisoning in cattle grazing crops

Extract

Although nitrate/nitrite poisoning of cattle, sheep and pigs has been recognized in New Zealand for many years, it has become more widely publicized in the past 2 years owing to the greater prevalence of poisoning and the involvement of hitherto unsuspected crops, notably ‘Grasslands Tama’ ryegrass. In this review, experiences with recent outbreaks of nitrate poisoning are compared with published observations. Throughout this paper the disease will be referred to as nitrate poisoning.     

Investigation of osteochondrosis in grazing beef cattle

Severe lameness attributed to osteochondrosis is described in an extensively managed Brahman herd grazing on improved native pasture. Clinical signs were observed in five animals, three of which were necropsied. The most prominent lesions were in the elbow and stifle joints. There was multiple fissuring and ulceration of thickened articular cartilage with numerous osteochondral bodies present in the joint spaces. All affected animals were entire males sharing a common ancestral sire. Inheritance and gender were suspected to be contributing factors in the development of the disease.     

The integration of grazing management and summer treatments for the control of trichostrongylid infections in Merino weaners

OBJECTIVE: To compare two strategies for the preparation of pastures that have reduced trichostrongylid infections during winter and spring for Merino weaners. DESIGN: A replicated field experiment was conducted over two successive years. A 'standard' strategy, comprising set-stocked wethers given anthelmintic treatments in late October and early February, was compared with a 'new' one in which intensive grazing for 1 month after each treatment and destocking for 1 or 2 months was integrated with the anthelmintic treatments. Paddocks prepared according to these strategies were set-stocked at 15 Merino weaners/ha from April to October inclusively. RESULTS: Contamination of pastures prepared according to the new strategy was substantially reduced compared to those of the standard strategy. Worm counts showed that on new strategy paddocks the numbers of trichostrongylid larvae, except Nematodirus spp, were reduced by 50 to 95% compared to standard strategy paddocks. Worm egg counts from the set-stocked weaners were reduced by about 50% on new strategy paddocks from April to October. Weaners grazing the new strategy paddocks grew significantly more clean wool (254 g, P = 0.01) and were significantly heavier in October (3.2 kg, P = 0.01) than weaners in the standard strategy paddocks. The improved production was attributable partially to better pasture growth early in winter and partially to reduced parasitism. CONCLUSION: The new strategy is a simple, practical and widely applicable example of the integration of grazing management with strategically timed anthelmintic treatments to reliably reduce trichostrongylid infections in weaners grazing during winter and spring.     

Effects of challenge with trichostrongylid nematode larvae on immunologically resistant grazing yearling sheep in South Australia.

Paddocks near Gawler, South Australia, were grazed by newly weaned sheep which received either no anthelmintic treatment, regular 3-weekly treatment or a single treatment in February. A decline in the faecal egg count of untreated sheep in autumn associated with the ingestion of infective larvae indicated that the sheep had developed a resistance to reinfection. At the end of the experiment, 10 sheep were experimentally infected with Trichostrongylus vitrinus larvae to demonstrate this resistance. Untreated sheep grew less wool and had lower body weights when compared with treated animals and were extremely 'daggy'. A single treatment in February did not prevent production losses or scouring.     

Sodium deficiency of grazing cattle in Papua New Guinea

Summary Sodium deficiency was suspected from low saliva sodium concentrations in cattle at various sites in the lowlands of Papua New Guinea. In an experiment at Erap, Morobe Province crossbred and pedigree Brahman heifers supplemented with copper, cobalt and/or common salt showed no response to copper or cobalt supplementation. There was a significant growth response (P<0·01) to salt supplementation over a 16 week period confirming sodium deficiency in these animals. The response in the crossbreds was twice that in the purebreds. Supplemented crossbred animals grew 0·78 kg/day over the 16 week experimental period.

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Resumen Se sospechó deficiencia de sodio al encontrar valores bajos de este elemento, en la saliva de bovinos que pastoreaban sitios bajos en Pápua. En un experimento en Erap, Provincia de Morobe, novillos Brahman puros y cruzados suplementados con cobre, cobalto y/o sal comun, no mostraron respuesta al cobre o al cobalto. Hubo respuesta significative (P<0·01) a la suplementación con sal en un período de 16 semanas, confirmando así la deficiencia de sodio en estos animales, con major respuesta en los cruces que en los Brahman puros. Los primeros aumentaron 0·78 kg/dia durante el período experimental de 16 semanas.

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Résumé Une carence en sodium a été suspectée en raison de faibles concentrations en sodium dans la salive de bovins paissant à divers endroits dans les plaines de Papouasie Nouvelle Guinée. Dans une expérience conduite à Erap, Province de Morobe, des génisses métissées et de pédigré Brahman recevant un complément de cuivre, cobalt et/ou de sel ordinaire n’ont pas réagi à la complémentation en cuivre ou cobalt. La complémentation en sel a entrainé une réponse de croissance significative (P<0,01) sur une période de 16 semaines, confirmant par là la carence en sodium chez ces animaux, avec une réponse deux fois plus importante chez les métisses que les animaux de race pure. Les animaux métissés recevant un complément ont eu un gain de poids de 0,78 kg par jour pendant la période expérimentale de 16 semaines.

     

Control of ostertagiasis in young cattle under intensive grazing

The present communication is concerned with the effect of treatment with anthelmintics on animal performance in a system of beef production which was designed to make maximum use of grass and grass products. In the system under investigation a Leader/Follower system of grzing (i.e. Grazing calves in front of older cattle in the rotation) is adopted with conserved and grazing areas alternating during the season.Calves dosed with either levamisole or fenbendazole at time of change to aftergrass in mid-June performed significantly better than undosed controls. As judged by changes in serum persinogen levels (and liveweight gains in 1 year), dosing calces with fenbendazole at the end of the first grazing season was effective in removing inhibited larvae of Ostertagia ostertagi. Significant differences were found in both carcase weight and killing out percentage in the fenbendazole treated group.