Studies in hogget rearing
Clarke, E. A.; Filmer, Daisy B.; Clarke, E. A.; Ruakura Animal Research Station; Filmer, Daisy B.; Ruakura Animal Research Station
Журнал:
New Zealand Journal of Agricultural Research
Дата:
1958
Аннотация:
SummaryTrials to determine the role of nematode parasites in the hogget ill-thrift syndrome were carried out over the years 1952-55 inclusive.Comparisons of systems of rotational grazing and set-stocking showed that rotational grazing gave no advantage over set-stocking in the level of parasitism or the thrift of the animal.Regular and frequent drenching with phenothiazine either under set-stocked or rotational-grazing management effectively reduced the level of parasitism but did not produce any worthwhile growth response in hoggets showing ill-thrift over the autumn and early winter.Drenching gave most effective control of H. contortus and was less effective against Trichostrongylus spp.Fine-particle phenothiazine (particle less than 10µ) was little more effective than coarse-particle phenothiazine in the control of H. contortus but showed a striking increase in the contro of Trichostrongylus spp. in the small intestine.The regular and frequent use of phenothiazine was shown to have no ill effects on the thrift of hoggets.Hoggets reared on typical dairy-farm pasture remained thrifty throughout the autumn irrespective of parasite levels.Hoggets reared on beef-fattening pastures, which were more akin to dairy-farm than sheep-farm pastures in length, showed no ill-thrift in the autumn in spite of varying levels of parasitism.Hoggets reared worm-free and weaned on to worm-free pastures showed typical ill-thrift in the autumn on the fresh growth of grass which followed topping and autumn rain. A small secondary effect of parasites was demonstrated following oral administration of nematode larvae.The interrelationship between plane of nutrition and level of parasitism is discussed.It is suggested that the concepts of subclinical, clinical, and pathological levels of nematode parasites have been established with little reference to other factors of a more primary nature in the autumn ill-thrift syndrome.It is concluded that nematode parasites with the possible exception of H. contortus play only a secondary role in the ill-thrift syndrome.
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