The use of genetically resistant sheep to control nematode parasitism

Gray, G. D.

doi:10.1016/s0304-4017(97)00105-2

Cited by 65 publications

(36 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For example, the elimi-nation of eggs per g of feces in wool sheep breeds has been investigated for many years in Australia and New Zealand (Windon 1996, Gray 1997. In Merino, there are lines of sheep selected for both increased and reduced genetic resistance (Woolaston et al 1990).…”

Section: Introductionmentioning

confidence: 99%

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

2013

View full text Add to dashboard Cite

Pesq. Vet. Bras. 33(4): 469-475, abril 2013 469 INTRODUCTIONThe frequent and continuous use of chemical anthelmintic drugs for deworming sheep flocks has resulted in the presence of lateral and multiple anthelmintic resistance in the parasites. This resistance leads to a concerning ineffectiveness of anthelmintics with large economic losses in sheep productivity (Coles et al. 2006, Papadopoulos 2008, Sargison 2011. Twenty-four countries have reported the presence of nematodes resistant to several anthelmintics (Jabbar et al. 2006). This situation has motivated workers around the world to search for alternative strategies to Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks 1Roberto González-Garduño 2 *, Pedro Mendoza-de Gives 3 and Glafiro Torres-Hernández 4ABSTRACT.-González-Garduño R., Mendoza- This study aimed to evaluate the variability in the fecal egg count (FEC) and the parasitic burden of naive hair sheep after grazing in nematode infected paddocks. The research was carried out in Tabasco, Mexico, during two periods (August and December). In each period 32 lambs were grazed for one month on African star grass (Cynodon plectostachyus) contaminated with gastrointestinal parasitic nematodes. FEC, packed cell volume (PCV) and body weight (BW) were recorded. Gastrointestinal worms were recovered at necropsy. Data were analyzed with the MIXED procedure of SAS using a model of repeated measurements over time. A higher number of Haemonchus contortus worms was found in December (2814±838) than in August (1166±305). The opposite occurred with Cooperia curticei (2167±393 and 3638±441, respectively). The FEC and correlation coefficient in respect to the worm burden were higher in December (6516 ± 1599, r=0.83, respectively) than in August (4364±771, r=0.44, respectively). A high variability in resistance-susceptibility to gastrointestinal nematodes (GIN) occurred in Katahdin × Pelibuey lambs after grazing.

show abstract

Section: Introductionmentioning

confidence: 99%

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

2013

View full text Add to dashboard Cite

show abstract

“…The emergence of nematode populations with resistance to anthelmintics and the concern about chemical residues in animal products threaten the sustainability of this approach (Waller, 2006). Alternative strategies for the control of gastrointestinal nematode infections, include selection of genetically resistant breeds and the development of effective vaccine (Gray, 1997;Newton and Munn, www.elsevier.com/locate/vetpar Available online at www.sciencedirect.com Veterinary Parasitology 158 (2008) [311][312][313][314][315][316][317][318] 1999). In sheep, the ability to acquire immunity and express resistance to gastrointestinal nematodes varies among and within breeds and is under genetic control (Stear et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Serum antibody responses in Creole kids experimentally infected with Haemonchus contortus

Bambou¹,

Chevrotière²,

Varo³

et al. 2008

Veterinary Parasitology

View full text Add to dashboard Cite

The objective of this study was to evaluate the relationship of parasite-specific serum antibodies with the resistance status of Creole kids. The average breeding values on egg output predicted in a context of natural infection at 11 months of age were distant of 1.07 genetic standard deviation between resistant and susceptible animals. After drenching the animals were maintained worm-free during 1 month until experimental infection with 10,000 Haemonchus contortus infective larvae (L3). Enzyme-linked immunosorbent assay was carried out in serum samples to determine the level of IgG, IgA and IgE anti-H. contortus L3 crude extracts and adult excretion/secretion products (ESP). Parasitological and blood immunological parameters were measured on the 2 extreme groups. Despite the absence of any typical signs of haemonchosis, susceptible kids had more than 11 times higher faecal egg counts (FEC) at 35 days post-infection (d.p.i.) than resistant kids had. Levels of immunoglobulin against H. contortus L3 and ESP increased significantly after infection in both groups. However, no difference in the host immune response mediated by immunoglobulin against H. contortus was evidenced between groups. This finding suggests that, in goats previously infected by H. contortus, a degree of protection occurred and the phenotypic and genetic segregation in resistant and susceptible animals were not related to the humoral immune response. The correlation coefficients between FEC and IgE anti-ESP (r = 0.593; P < 0.05 was significant in both resistant and susceptible animals. Such correlation suggesting a hypersensitivity reaction dependent on worm prolificacy has never been described. This result needs further studies to understand the mechanisms underlying this observation. #

show abstract

“…Good management can bring down parasitic infections which seem the biggest health challenge (Dimander et al, 2000;Hö glund et al, 2001;Carstensen et al, 2002), and there is a cautious optimism regarding future possibilities for coping with parasites in ways complying with the organic standards (Niezen et al, 1996;Thamsborg et al, 1999). This optimism is supported by that conventional farming has an interest in finding alternatives to chemical treatments because of increasing problems with resistant parasites (e.g., Barger, 1997;Gray, 1997;Waller, 1999).…”

Section: The Potential Of Organic Farming In Relation To Welfarementioning

confidence: 89%

Natural living—a precondition for animal welfare in organic farming

Lund

2006

Livestock Science

121

View full text Add to dashboard Cite

This article discusses animal welfare in organic farming systems in relation to values and aims in organic farming. It sums up experiences from a 4-year interdisciplinary project. An important finding is that animal welfare is understood somewhat differently in organic farming from what is common in conventional agriculture. It is interpreted in terms of natural living, which includes the possibility to perform a natural behaviour, feed adapted to the animal's physiology and a natural environment. Some of the criticism of animal welfare in organic farming may stem from different understandings of what bwelfareQ actually means. However, although welfare is an important aim in organic farming, the overall concern is to develop sustainable farming systems. This causes some welfare dilemmas. For example, a healthy system does not automatically mean good welfare for the individual. Based on available literature the actual welfare situation in organic systems was scrutinized. Unfortunately little research has been done, but a careful conclusion was that animal health is as good or better than in conventional farming-with the exception of parasitic diseases. Organic farming systems have a bwelfare potentialQ, but organic farmers must deal with the dilemmas and take animal welfare issues seriously. D

show abstract

The use of genetically resistant sheep to control nematode parasitism

Cited by 65 publications

References 43 publications

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

Variability in the fecal egg count and the parasitic burden of hair sheep after grazing in nematode infected paddocks

Serum antibody responses in Creole kids experimentally infected with Haemonchus contortus

Natural living—a precondition for animal welfare in organic farming

Contact Info

Product

Resources

About