Infestation Of Sheep Research Articles

The effect of nutrition on age resistance of sheep to infestation withnematodirusspp

Abstract Extract Reviews of the literature dealing with the interrelationships of nutrition and helminth infestation have been given by Whitlock (1949), Chandler (1953), Hunter (1953), and Frye (1955). Much of the evidence concerning the effects of nutrition on helminth infestation in sheep is the result of field observations. As Stewart and Gordon (1953) have pointed out, especially in the case of infestations with Trichostrongylus colubriformis, the opinion, based on such observations, that nutrition is of prime importance in the resistance of sheep to infestation possibly overlooks other factors concerned. Furthermore, as stressed by Gordon (1960), the distinction between resistance to the establishment of an infestation and resistance to the effects of an infestation is not always clearly stated. However, this differentiation is essential to the understanding of the effect of nutrition on immunity.

COXIELLA BURNETI IN KANGAROOS AND KANGAROO TICKS IN WESTERN QUEENSLAND

SUMMARYComplement‐fixing antibodies to Coxiella burneti were present in 23 p.c. of kangaroos collected in western Queensland, and agglutinins in 15 p.c. Red kangaroos, Megaleia rufa, showed a higher incidence of complement‐fixing antibodies (33 p.c.) than grey kangaroos, Macropus major (12 p.c.). In three areas, the incidence of complement‐fixing antibody in M. rufa was between 46 and 54 p.c.C. burneti was isolated in mice from the blood of one Macropus major.Thirteen isolations were made from nearly 3,000 ornate kangaroo ticks, Amblyomma triguttatum, collected from kangaroos, goats and sheep. The titre of infectivity of infected ticks for mice was usually in the range 10−6 to 10−9.Infection of kangaroos and A. triguttatum was found over a considerable area, between 24 and 28° S. and 144 and 149° E., in western Queensland.It thus seems probable that a natural kangaroo‐tick cycle exists. The three‐host life cycle and wide host range of this tick would allow it to spread infection to domestic animals as well as kangaroos. Infestation of sheep would bring infected ticks into contact also with workers in the sheep‐shearing industry, and was probably responsible for recent outbreaks of Q fever among them.

Immune reactions to Trichostrongylus colubriformis infestation in sheep.

IN infestation of sheep with Trichostrongylus colubriformis both the intake of larvæ and infestation with adult worms stimulate the production of antibodies. These can be detected by means of a complement fixation test with an antigen prepared from ground larvæ1.

EPIDEMIOLOGY OF HELMINTH INFESTATION IN SHEEP. SOUTH AUSTRALIAN ASPECTS

EPIDEMIOLOGY OF HELMINTH INFESTATION IN SHEEP. SOUTH AUSTRALIAN ASPECTS

A study of subclinical worm infestation in sheep: part III. The effect on wool production

1. The results of five experiments, comparing the wool production of worm free and infected sheep, are described.2. Worm-free sheep produced (a) 12·0–38·8% higher total fleece weights and (b) 17·2–43·2% more clean, dry wool per unit area than infected sheep. None of the infestations was higher than occurs naturally in the field, but the greatest effects were associated with a low level of nutrition.3. It is suggested that the precise effect of worm infestation on wool production will depend upon the age of the host when first infected, the size of the infestation and the rate of wool growth at the time when the infestation is at maximum.

A study of subclinical worm infestation in sheep: I. The effect of level of infestation on the growth of the lamb

1. The experiment described confirmed earlier findings that a folding management across wormfree pasture was capable of preventing infection of the lamb by all species except Strongyloides papillosus.2. The growth and productivity of lambs infected at five different levels were compared with those of ‘worm-free’ controls grazing with them.3. Live-weight gain of the total infected group was significantly depressed; within the infected group only level 5 differed significantly from the control group.4. Loss of productivity was, in this experiment, associated with egg counts between 30 and 57 e.p.g.5. The problem of definig a ‘tolerance’ level below which no appreciable damage occurs is discussed in relation to the results obtained.

LIVER FLUKE (FASCIOLA HEPATICA) INFESTATION IN SHEEP AND ITS SEASONAL INCIDENCE IN NORTHERN NEW SOUTH WALES.

Australian Veterinary JournalVolume 30, Issue 5 p. 152-152 LIVER FLUKE (FASCIOLA HEPATICA) INFESTATION IN SHEEP AND ITS SEASONAL INCIDENCE IN NORTHERN NEW SOUTH WALES. H. G. Osborne B.V.SC, H. G. Osborne B.V.SC 336 Grey Street, Glen limes, P.O. Box 171 7th April, 1954.Search for more papers by this author H. G. Osborne B.V.SC, H. G. Osborne B.V.SC 336 Grey Street, Glen limes, P.O. Box 171 7th April, 1954.Search for more papers by this author First published: May 1954 https://doi.org/10.1111/j.1751-0813.1954.tb08197.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume30, Issue5May 1954Pages 152-152 RelatedInformation

Studies on resistance of sheep to infestation with Haemonchus contortus and Trichostrongylus spp. and on the immunological reactions of sheep exposed to infestation. III. The antibody response to infestation with Trichostrongylus spp.

In infestation of sheep with Trichostrongylus spp., both the intake of larvae and infestation with adult worms stimulated the production of antibodies. The character of the antibody response in infestation with Trichostrongylus spp. thus differed from that caused by Haemonchus contortus. Sera of sheep dying from infestation with Trichostrongylus spp. were negative to the complement fixation test. It was found that older sheep responded serologically earlier and more vigorously to infestation with Trichostrongylus spp. than did young sheep. Subsequent doses of larvae of Trichostrongylus spp. elicited a more rapid and grester serological response, even in young sheep, than an initial dose of larvae. Previous infestation with H. contortus did not result in resistance to Trichostrongylus spp., whereas previous infestation with Trichostrongylus spp. heightened the resistance of sheep to subsequent infestation with the same species. It is concluded that the relative resistance of older sheep to Trichostrongylus spp. is due, a t least in part, to an earlier immunological response which is strengthened by subsequent doses of larvae. When infective larvae of Trichostrongylus spp. were superimposed upon an existing infestation of the same species, the egg count declined ;apidly and the development of the superimposed larvae resisted Doses of infective larvae of Trichostrongylus spp. had no apparent effect on the egg counts of sheep infested with H. contortus.

The Effects of Environmental and Hereditary Factors on Trichostrongylid Worm Infestation in Sheep

The Effects of Environmental and Hereditary Factors on Trichostrongylid Worm Infestation in Sheep

An analysis of environmental and genetic factors influencing stomach-worm infestation in sheep

Faecal examination for Trichostrongyle eggs of ewes of known ages sired by two different rams were made weekly over a period of two months from September to November 1937. All data on the egg counts were quantitative. Though the numbers of ewes studied were somewhat limited, the results were consistent and indicate that at least three different factors influence the degree of stomach-worm infestation. The season of the year is the first variable. Age of the ewe is the second, although, in these data, age beyond 2 years 8 months ceased to be important. The third and most important variable influencing stomach-worm infestation is genetic constitution for resistance and susceptibility. Judging from these results, genetic selection should effectively change the degree of resistance or susceptibility in populations of sheep.

Miscellaneous Experiments with Anthelminthics, Chiefly Alkyl-Chlorides, in the Treatment of Nematode Infestations of Sheep

Miscellaneous Experiments with Anthelminthics, Chiefly Alkyl-Chlorides, in the Treatment of Nematode Infestations of Sheep

The Control of Tick Infestation and a Related Disease of Lambs in North Wales

(1) An account is given of a serious infestation in sheep and lambs by Ixodes ricinus in the uplands of Denbighshire, North Wales.(2) This infestation was accompanied by serious disturbance of health resulting in the general deterioration of the flock and the death of lambs.(3) Experimental dippings were commenced in 1924, using a special “short-interval” arsenical dip supplied by the Cooper Technical Bureau, London. Serial dippings were made each spring at five-day intervals. When possible an early autumn series was conducted.(4) The objects were (a) to control the infestation, (b) to control the diseased condition, and (c) to attempt to eradicate ticks from the land.(5) The control of both the ticks and the disease were easily effected. A few sporadic cases of disease did occur during the course of the experiment.(6) Eradication has not yet been accomplished, but the average number of ticks was reduced from 121 per animal in May 1924 to 0-96 per animal in July 1926.(7) It is therefore suggested that short-interval dipping for serious tick infestation in sheep is practicable on British hill farms, and that resultant mortality from disease can thereby be reduced.

Note on the Infestation of Sheep with Ticks

Note on the Infestation of Sheep with Ticks