Helminthological Investigations on an Argyllshire Hill Farm

Self Cite

A survey of the helminths of Scottish hill sheep, made by collecting over seven hundred viscera from sheep which died from disease or accidents on over eighty farms, has shown that worms are the direct or indirect cause of the death of many sheep, and of loss in condition of many more.Infestations of H. contortus increase in incidence and severity in the late spring, but the majority of hill sheep are not infested with it and it is not a serious problem unless lack of herding, bad weather, etc. harm the sheep.Ostertagia spp. are often the most numerous species found in Scottish hill sheep; their numbers increase considerably for several weeks in the spring and to a less extent and for a shorter time in the autumn. Any prophylactic dosing programmes for lambs, hoggs or adult sheep must include Ostertagia spp. in the species against which they are directed.The numbers of T. axei increase in Scottish hill sheep during the winter and for some weeks from March onwards contribute to the pathogenic effect of clinical and subclinical helminthiasis of sheep.

Section: Lam8s- Hogcs-c1mmcrs-•cwes-mentioning

confidence: 93%

Section: Severity Of Infestationsmentioning

confidence: 99%

A Survey of the Helminths of Scottish Hill Sheep

Parnell¹,

Rayski²,

Dunn³

et al. 1954

Self Cite

“…There is thus good evidence confirming that the post-parturient rise is the result of a generalised non-specific loss of resistance by the ewe to the nematode parasites in the alimentary tract {vide Morgan et al, 1951;Wilson et al, 1953 ;Parnell et al, 1954). The parasite population at that time may therefore be related to the availability of the different species from whatever source and the initial degree of resistance.…”

Section: I5oo-i Iooch C7> 5oomentioning

confidence: 99%

“…With regard to the aetiology of the post-parturient rise, a number of theories have been put forward. Morgan and his co-workers found an increased worm burden in spring in male and one year old sheep as well as in breeding ewes (Morgan et al, 1951 ;Wilson et al, 1953). They concluded that of prime importance was the malnutrition from which hill sheep commonly suffer in.…”

Section: I5oo-i Iooch C7> 5oomentioning

confidence: 99%

Studies on the Worm Populations in the Alimentary Tract of Breeding Ewes

Connan

1968

Groups of breeding ewes were slaughtered at intervals before and after lambing in March. A post-parturient rise in egg count was observed in which Ostertagia spp. were dominant but in which other species took part, in particular Haemonchus contortus, Nematodirus battus and Chabertia ovina. The important contribution made by dormant larvae of Ostertagia spp. was confirmed but it was also found that reinfection greatly increased the number of worms present while the earliest part of the rise, often beginning prior to parturition, was probably due to the increased fecundity of adult worms already present. Adults of H. contortus present in ewes after lambing were derived from the maturation of dormant larvae and it is probable that the same applied to C. ovina. The close association of the postparturient rise with lactation rather than with pregnancy or parturition was shown and two possible explanations for this were discussed.

“…When the immature histotropic stages were being looked for in Scottish hill sheep (Morgan et al, 1951(Morgan et al, , 1952Parnell, 1956;Parnell et al, 1954 ;Wilson et al, 1953) in the early 1950's, a compressorium was used, and only very small numbers were found; 121 was the highest count, but now it seems probable that others were missed. Even when digested out of the mucosa or submucosal wall, and searched for under a dissecting microscope they can easily be hidden.…”

Section: Discussionmentioning

confidence: 99%

Observations on the Seasonal Variations in the Worm Burdens of Young Sheep in Southern Western Australia

Parnell¹

1962

Observations, limited to one year, on autumn born and spring born lambs and weaners indicated that very few infective larvae of bursate nematodes, with the exception of those of Nematodims spp., were ingested after the middle of spring, with the result that at least until they were eight months old, and probably older, spring born lambs were comparatively lightly infested.These observations also suggested that retarded larvae, especially the histotropic stages, are the cause of the “summer rise” in weaners and that they also cause the “parturition rise” in autumn lambing ewes, and can be the cause of increased worm egg production in wethers.It seems probable that the “summer rise” of sheep in the southern part of Western Australia is comparable to the “spring rise” of sheep in the United Kingdom and elsewhere.