Regulation of the resistance to nematode parasites of single-and twin-bearing Merino ewes through nutrition and genetic selection

Title
Regulation of the resistance to nematode parasites of single-and twin-bearing Merino ewes through nutrition and genetic selection
Publication Date
2003
Author(s)
Kahn, Lewis
( author )
OrcID: https://orcid.org/0000-0002-3679-4530
Email: lkahn3@une.edu.au
UNE Id une-id:lkahn3
Knox, MR
Walkden-Brown, Steve W
( author )
OrcID: https://orcid.org/0000-0002-0638-5533
Email: swalkden@une.edu.au
UNE Id une-id:swalkden
Lea, JM
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Elsevier BV
Place of publication
Netherlands
DOI
10.1016/S0304-4017(03)00099-2
UNE publication id
une:405
Abstract
Periparturient Merino ewes obtained from lines of sheep that had been selected either for increased resistance to Haemonchus contortus (R) or at random (C) were supplemented, while grazing at pasture, with either nil or 250 g/day cottonseed meal (CSM) for the 6 weeks prior to or the 6 weeks after the start of parturition. Ewes from both supplement groups had lower (mean 66% reduction) faecal egg counts (FECs) during the postpartum period and this coincided with a period of maternal body weight loss. Factors which increased the rate of maternal body weight loss, such as pregnancy and lactation status, also increased FEC. Evidence is presented that the magnitude of the periparturient rise (PPR) in FEC in grazing ewes will be greatest during periods of maternal weight loss and at these times supplementation to increase metabolisable protein (MP) supply will be most effective in increasing resistance to nematode parasites. The resistance of R ewes to nematode parasites was greater than that of ewes throughout the experiment and was sufficiently low such that anthelmintic treatment in a commercial environment may not have been required. Irrespective of actual FEC, ewes from all treatment combinations exhibited a PPR in FEC. Reduced FEC of R ewes resultedin reduced apparent pasture larval contamination after 18 weeks of continuous grazing but supplementation was ineffective in this regard. It is suggested that integrated parasite management (IPM)programs for periparturient ewes should make use of both protein supplementation and genetic selection to increase worm resistance and reduce dependency on anthelmintics for worm control.
Link
Citation
Veterinary Parasitology, 114(1), p. 15-31
ISSN
1873-2550
0304-4017
Start page
15
End page
31

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