Quantitative studies of ovine haemonchosis. 2. Relationship between total worm counts of Haemonchus contortus, haemoglobin values and bodyweight

Roberts J.L. and Swan R.A. (1982) Quantitative studies of ovine haemonchosis. 2. Relationship between total worm counts of Haemonchus contortus, haemoglobin values and bodyweight. Veterinary Parasitology, 9 3-4: 217-222. doi:10.1016/0304-4017(82)90065-6


Author Roberts J.L.
Swan R.A.
Title Quantitative studies of ovine haemonchosis. 2. Relationship between total worm counts of Haemonchus contortus, haemoglobin values and bodyweight
Journal name Veterinary Parasitology   Check publisher's open access policy
ISSN 0304-4017
Publication date 1982-01-01
Sub-type Article (original research)
DOI 10.1016/0304-4017(82)90065-6
Open Access Status Not yet assessed
Volume 9
Issue 3-4
Start page 217
End page 222
Total pages 6
Subject 1103 Clinical Sciences
2405 Parasitology
3400 Veterinary
Abstract The relationships between Haemonchus contortus burdens, haemoglobin levels and bodyweight, were examined in 50 commercial Merino sheep, 9-18 months of age, in south-east Queensland where haemonchosis was endemic. Worm counts and haemoglobin levels were predictable (P<0.001, r=0.68) from the equations log worm count = B.wtt × 0.06942 + log worm count × (-2.18896) + 12.51557. Bodyweight was not predictable from either worm counts or haemoglobin levels. Although bodyweight was represented in both equations, it was only a small and insignificant contributor. When haemoglobin levels became moderately depressed (<10.5 g%) or severly depressed (<8.0 g%), then the number of worms associated with these haemoglobin levels varied with the bodyweight of the sheep. For sheep up to 20 kg, 10.5 g% Hb was associated with 112 worms and 8 g% with 355 worms. However, 355 worms caused only moderate depression of Hb levels in sheep over 50 kg, and 1259 worms were required to cause severe depression (<8.0 g%) in sheep over 50 kg. Three sheep were found to be severely anaemic in the presence of less than 100 worms. It was postulated that additional factors of time and nutrition may have affected these sheep. The sheep were of low bodyweight, in poor condition (low fat score) and were subject to high stocking rates on long grass pastures and high rainfall in autumn. Other internal parasite species present were Nematodirus spp. and Trichostrongylus spp. However, their numbers were low (57 and 218 worms, respectively) and did not contribute to anaemia. The correlation between H. contortus and Nematodirus spp. was found to be negative but non-significant (r = -0.26, P<0.01), while the correlation between H. contortus and Trichostrongylus spp. was positive and significant (r = 0.38, P<0.01).
Q-Index Code C1
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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