A modified technique for the estimation of the number of infective nematode larvae present on pasture, and its application in the field under South Australian conditions

Martin, R.R.; Beveridge, Ian; Pullman, A.L.; Brown, T. H.

doi:10.1016/0304-4017(90)90068-m

Cited by 28 publications

(19 citation statements)

References 17 publications

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“…The number of larvae on the pasture was estimated using a method adapted from Martin et al (1990). Briefly, larvae were washed off the pasture and allowed to settle in large bins.…”

Section: Experimental Designmentioning

confidence: 99%

Merino ewes bred for parasite resistance reduce larval contamination onto pasture during the peri-parturient period

Williams

Greeff

Vercoe

et al. 2010

Animal

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The peri-parturient period is crucial for controlling worms as the acquired immunity of ewes is disrupted, resulting in an increase in faecal worm egg counts. Two hypotheses were tested in this experiment -that ewes bred for worm resistance would have lower faecal worm egg counts than unselected control ewes, during late pregnancy and lactation, under similar but separate grazing areas; and also that numbers of infective nematode larvae would be lower on pastures grazed by resistant ewes than pastures grazed by unselected control ewes. Faecal samples were collected from resistant and unselected ewes in late pregnancy and early lactation, during the winter rainfall season, and analysed for numbers of Trichostrongylus colubriformis and Teladorsagia circumcincta. Pasture samples were taken 1 week before and 7 weeks after lambing started and analysed for infective larvae. In all sheep, worm egg counts rose 2 weeks prior to lambing and continued into lactation. Worm egg counts were significantly lower in the resistant ewes from 1 week before lambing to 2 weeks after lambing. There were no differences in egg counts between single-and twin-bearing ewes in the resistant line. However, twin-bearing control ewes had significantly higher egg counts than single-bearing control ewes. Following lactation, plots grazed by resistant ewes had substantially less contamination with T. colubriformis larvae, but there were no differences in numbers of T. circumcincta larvae. Our results demonstrate that sheep bred for worm resistance has lower worm burdens during the peri-parturient phase and that lambs born to resistant ewes face a lower larval challenge during their introduction to grazing. In our environment, selection for low worm egg counts has produced sheep highly resistant to T. colubriformis, but has had less impact on resistance towards T. circumcincta.

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“…The number of larvae on the pasture was estimated using a method adapted from Martin et al (1990). Briefly, larvae were washed off the pasture and allowed to settle in large bins.…”

Section: Experimental Designmentioning

confidence: 99%

Merino ewes bred for parasite resistance reduce larval contamination onto pasture during the peri-parturient period

Williams

Greeff

Vercoe

et al. 2010

Animal

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“…Reliable results depend on the use of methodologies that allow for a precise quantification of the number of L3 in the pasture. Several techniques exist for the recovery of L3 from the pasture, as the use of animals with an esophageal fistula (GETTINBY et al, 1985), tracer animals (MARTIN et al, 1990), and sampling directly from the pasture (TAYLOR, 1939).…”

Section: Introductionmentioning

confidence: 99%

Comparison of two methods for the quantification of gastrointestinal nematode infective larvae from pasture

Piza¹,

Almeida

Pariz

et al. 2019

SCA

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The economic losses caused by gastrointestinal nematodes are one of the biggest obstacles in the small ruminants production. Understanding the population dynamics of the infective larvae (L3) in the pasture is the key point to develop control programs, and reliable results depend on the used methodology to quantify L3 numbers. The use of the sampling directly from the pasture appears as a viable option, since it is not required the use of animals with an esophageal fistula or tracer animals, decreasing the costs involved in the study. Therefore, the present project, which had as objective evaluate the efficiency of two collection methods for quantification of L3 in the pasture, utilized 64 lambs (n = 16) allocated to four integrated crop-livestock systems (treatments) with 12 paddocks each. Pasture samples were collected every nine days. The W method consists in traversing the area in the form of a W and again an inverted W, forage samples being collected every 10 steps, and the Square method, in tossing a 0.16 m 2 square to four random points within the area, the forage within the square being collected after each toss. After the forage samples had been processed, the L3 were recovered and identified. Cohen's Kappa coefficient (k) was determined. The W-transect and Random-plot methods did not differ (p ≥ 0.05) with respect to the number of L3 recovered from the pasture, and a positive correlation was found between them, suggesting agreement with one another, being that when the number of L3 recovered by the W-transect method increases, the same occurs in the Random-plot technique. The Random-plot method, which is already used to collect samples of forage for chemical analyses, can also be employed to estimate the pasture contamination by L3. The W-transect and Random-plot methods showed to be important in the epidemiological study of gastrointestinal nematodes in sheep. Therefore, the use of both on the same occasions and with different purposes, with one complementing the information that is not provided by the other, may be more effective in the investigation of environmental contamination by L3 of gastrointestinal nematodes. ResumoAs perdas econômicas causadas por nematódeos gastrintestinais são um dos maiores entraves na produção de pequenos ruminantes. Entender a dinâmica populacional das larvas infectantes (L3) no capim é o ponto chave para que se desenvolva programas de controle, e resultados confiáveis dependem das metodologias utilizadas para quantificar o número dessas L3. O uso da amostragem diretamente da pastagem aparece como uma opção viável, já que não requer o uso de animais fistulados ou traçadores, reduzindo os custos envolvidos no estudo. Assim, no presente estudo, que teve como objetivo avaliar a eficácia de dois métodos de coleta para quantificação de L3 na pastagem, foram utilizados 64 cordeiros (n = 16) alocados em quatro sistemas integrados de produção agropecuária (tratamentos) com 12 piquetes cada. As amostras de pasto foram coletadas a cada nove dias. O método W consiste em percorrer a...

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“…Larvae on herbage were recovered fortnightly from bulked herbage samples (N = 40/paddock) cut at random to groundlevel from Break 1 of each treatment before grazing. Larvae were counted using a modification of the technique described by Martin et al (1990). Monitoring continued until 10 August 1992 during which time the pastures remained ungrazed.…”

Section: Experiments 1 (1991-92)mentioning

confidence: 99%

Effect of herbage species and feeding level on internal parasites and production performance of grazing lambs

Scales

Knight

Saville

1995

New Zealand Journal of Agricultural Research

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A modified technique for the estimation of the number of infective nematode larvae present on pasture, and its application in the field under South Australian conditions

Cited by 28 publications

References 17 publications

Merino ewes bred for parasite resistance reduce larval contamination onto pasture during the peri-parturient period

Merino ewes bred for parasite resistance reduce larval contamination onto pasture during the peri-parturient period

Comparison of two methods for the quantification of gastrointestinal nematode infective larvae from pasture

Effect of herbage species and feeding level on internal parasites and production performance of grazing lambs

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