A field study of nematode parasite populations in the lactating ewe

O’Sullivan, Belinda; Donald, A.D.

doi:10.1017/s0031182000041135

Cited by 124 publications

(28 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This could be of particular benefit to organic flocks where the routine use of such supplements is permitted under current regulations. Nematode egg counts of ewes fell to negligible levels in summer, coinciding with the onset of drying-off, in accordance with the pattern typically observed in lambing flocks (O'Sullivan & Donald 1970). This coincided with relatively high faecal egg counts in lambs, which were on average 3 to 4 months of age.…”

Section: Discussionsupporting

confidence: 84%

“…Thus there is an important seasonal component, whereby the post-parturient rise in ewe faecal egg counts is indeed a "spring rise" phenomena in Sweden. However in comparison with observations made elsewhere, this rise is relatively low (O'Sullivan & Donald 1970). Recommendations as to whether or not, organic farmers should dose their flocks in spring, are based on the presence of infective larvae of H. contortus in faecal cultures.…”

Section: Discussionmentioning

confidence: 92%

See 1 more Smart Citation

The dynamics, prevalence and impact of nematode infections in organically raised sheep in Sweden.

2003

Aust Veterinary J

View full text Add to dashboard Cite

was carried out on organically reared sheep flocks throughout Sweden. The aim was to determine the prevalence and intensity of nematode infections and to establish relationships between sheep management practices and parasite infections. Faecal samples from ewes and lambs were collected from 152 organic flocks around lambing-time and during the grazing-period for analysis. Results were compared with the different management practices that farmers use to prevent parasitism in their flocks. A high proportion of the flocks was infected with nematodes. The most prevalent species were Haemonchus contortus, Teladorsagia circumeincta, Trichostrongylus axei, T. colubriformis and Chabertia ovina and infections progressively increased during summer in lambs grazing on permanent pastures. Severity of parasitic infection in lambs was highly dependent on egg output from the ewes. H. contortus was found in 37% of the flocks, even at latitudes approximating the Polar Circle. Nematodirus battus was recorded for the first time in Sweden during the course of this study. Lambs turned out onto permanent pasture showed higher nematode faecal egg counts (epg) than lambs that had grazed on pastures, which had not carried sheep the previous year. This beneficial effect of lambs grazing non-infected pastures persisted if the ewes were treated with an anthelmintic before turn-out and if the lambs were kept on pastures of low infectivity after weaning. In lambs, the prevalence and the magnitude of their egg counts were higher during autumn in flocks where lambs were slaughtered after 8 months of age, compared with flocks where all lambs were slaughtered before this age. These results will be used in providing advice to farmers of ways to modify their flock management in order to minimise the use of anthelmintics, but at the same time efficiently produce prime lambs.

show abstract

Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 92%

The dynamics, prevalence and impact of nematode infections in organically raised sheep in Sweden.

2003

Aust Veterinary J

View full text Add to dashboard Cite

show abstract

“…Finally, there is evidence that the extent of periparturient BIP differs between species of gastrointestinal nematodes in sheep (O'Sullivan & Donald, 1970, 1973Gibbs & Barger, 1986;Jackson et al 1988;Barger, 1993). In general, periparturient sheep show a more pronounced breakdown of immunity to the abomasal nematode T. circumcincta than to Trichostrongylus spp.…”

Section: Broadening the Nutritional Basis For Breakdown In Immunity: mentioning

confidence: 99%

Nutrient partitioning between reproductive and immune functions in animals

2001

View full text Add to dashboard Cite

The physiological processes that underlie the reproductive cycle impose considerable metabolisable protein (MP) demands on a female, especially during the periparturient period. When MP supply falls short of MP demand (i.e. MP becomes scarce), certain, if not all, bodily functions are expected to be penalised. It has been proposed that partitioning of scarce MP is prioritised to reproductive rather than to immune functions. In other words, at times of MP scarcity, the penalty on expression of immunity would be expected to be greater than that on reproduction. This hypothesis forms a nutritional basis for the occurrence of periparturient breakdown of immunity to parasites (BIP), which can be observed in many host-parasite systems.In the present review we explore this nutritional basis, using periparturient sheep infected with the abomasal nematode Teladorsagia circumcincta as an example, and attempt to quantify its occurrence. Evidence supporting the nutritional basis of periparturient BIP is reviewed, covering experiments in which nutrient supply (from both exogenous and endogenous sources) and/or nutrient demand were manipulated. Quantitatively, MP requirements for expression of immunity to T. circumcincta were estimated to be about 1 g/kg metabolic body weight (body weight 0·75 ) per d, approximately 5% of the maximum MP requirements of periparturient sheep. The major component of this requirement was assumed to be for replenishing irreversible plasma protein losses into the gastrointestinal tract. Although confirmation of this estimate is required, such estimates may be used to improve the known MP requirements of periparturient animals, enabling the extent and the consequences of periparturient BIP to be minimised. Nutrient partitioning around parturition: Immunity to parasites: Protein requirements of sheepBIP, breakdown of immunity to parasites; FEC, faecal egg count; Ig, immunoglobulin; MP, metabolisable protein

show abstract

“…The PPR may derive from an increase in adult parasite populations by an increased rate of establish- 991 The periparturient rise in Merino ewes ment of newly ingested larvae which develop to the adult stage without inhibition, as well as by the resumption of development of previously inhibited fourthstage larvae. In addition, both newly acquired and established adult female parasites may show increased fecundity (O'Sullivan & Donald, 1970;Urquhart et al, 1996). Thus, the high percentage of H. contortus could be explained by newly ingested larvae of this parasite and/or the maturation of hypobiotic larvae that arrested the development over winter.…”

Section: Parasitological Analysismentioning

confidence: 99%

Modelling the faecal worm egg count curve during the periparturient period in Uruguayan Merino sheep

Goldberg¹,

Ciappesoni²,

Aguilar³

2012

Span. j. agric. res.

View full text Add to dashboard Cite

Disease caused by gastrointestinal nematodes (GIN) is one of the main constraints for sheep production worldwide. Although adult categories are more resistant to GIN, a temporary loss of acquired immunity is presented around parturition, which results in the so-called "periparturient rise" (PPR) in fecal excretion of GIN eggs. The objective of the present work was to study the dynamic of the PPR and to model the faecal worm egg count (FEC) curve during the periparturient period in Uruguayan Merino sheep. Faecal samples were collected from lambing ewes during 2009 and 2010 parturitions. FEC and infective larvae cultures of each sampling were recorded. A total of 2,121 records from 748 ewes, the progeny of 107 sires, were used in the statistical analysis. FEC data were normalized using two logarithmic transformations: Log FEC = Log e (FEC + 100) and Log FEC_st (Log FEC with the variance standardized within contemporary group). Three functions were compared to shape the PPR curve. Haemonchus spp. was the most prevalent parasite. Log FEC_st was the selected response variable of the model, for its better adjustment to a normal distribution and a more homogeneous residual variance. The fixed regression model with Legendre polynomials was the selected one, based on the selection model criteria (Akaike & Schwarz Bayesian Information Criteria). The highest egg output was observed between two and four weeks post-lambing. In conclusion, the PPR observed in Uruguayan Merino lambing ewes had the maximum egg output matched with the milk production peak.Additional key words: gastrointestinal nematodes; Haemonchus contortus; lambing ewes; periparturient rise. Resumen Modelación de la curva del recuento de huevos de parásitos durante el período del periparto en ovinos Merino uruguayoLa infección por nematodos gastrointestinales (GIN) es una de las principales limitantes de la producción ovina mundial. Si bien los adultos son más resistentes a los GIN, una pérdida temporal de la inmunidad adquirida se presenta en el período del periparto, resultando en el "alza de lactación" (PPR) en la eliminación de huevos de GIN (HPG). El objetivo del presente trabajo fue estudiar la dinámica del PPR y obtener la curva del recuento del HPG durante el periparto en ovejas Merino uruguayo. Se recogieron muestras de heces de ovejas en las pariciones 2009 y 2010, realizándose HPG y coprocultivo de cada muestreo. Para el análisis estadístico se utilizaron 2,121 datos de 748 ovejas, hijas de 107 padres. Se llevaron a cabo dos transformaciones logarítmicas de manera que los datos siguieran una distribución normal: Log HPG = Log e (HPG+100) y Log HPG_st (Log HPG con la varianza normalizada dentro del grupo contemporáneo). Se compararon tres funciones para modelar la curva del PPR. Haemonchus spp. fue el género más frecuente. Log HPG_st fue la variable de respuesta del modelo seleccionada, por el mejor ajuste a la distribución normal y mayor homogeneidad de la varianza residual. Se seleccionó el modelo con polinomios de Legendre, en base a los c...

show abstract

A field study of nematode parasite populations in the lactating ewe

Cited by 124 publications

References 13 publications

The dynamics, prevalence and impact of nematode infections in organically raised sheep in Sweden.

The dynamics, prevalence and impact of nematode infections in organically raised sheep in Sweden.

Nutrient partitioning between reproductive and immune functions in animals

Modelling the faecal worm egg count curve during the periparturient period in Uruguayan Merino sheep

Contact Info

Product

Resources

About