Salmonellosis in sheep and zinc oxidedosing

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Madam:– For several years we have been concerned with developing safe and effective methods of administering zinc to farm animals for the control of facial eczema. In none of our trial work involving repeated daily, weekly and fortnightly dosing of zinc oxide to sheep not vaccinated against salmonellosis has salmonellosis been encountered. Recently two reports(1 Allworth, M.B., West, D.M. and Bruere, A.N. 1985. Salmonellosis in ram hoggets following prophylactic zinc dosing. N.Z. vet. J., 33: 171–171. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]),(3 Neilsen, F.J.A., Jagusch, K.T., Gray, M.G. and Maclean, K.S. 1985. Acute enteritis and deaths in .sheep from Salmonella hindmarsh associated with oral dosing with zinc oxide. N.Z. vet. J., 33: 148–149.  [Google Scholar]) have suggested that high doses of zinc oxide have played a part in the aetiology of two outbreaks of salmonellosis in sheep and we thank the authors of both papers for pointing out their field observations. In the first outbreak(3 Neilsen, F.J.A., Jagusch, K.T., Gray, M.G. and Maclean, K.S. 1985. Acute enteritis and deaths in .sheep from Salmonella hindmarsh associated with oral dosing with zinc oxide. N.Z. vet. J., 33: 148–149.  [Google Scholar]) the sheep were subjected to exceptional stress (thrce days of mustering, yarding, drafting, tagging, weighing, bleeding, dosing and trucking). Even so it appeared that the "zinc dosed" and not the "nonzinc" group were affected by salmonellosis, but in exceptional circumstances.     

Salmonellosis in ram hoggets following prophylactic zinc dosing

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Madam:– There has been considerable use in recent times of zinc oxide as an oral drench to prevent the occurrence of facial eczema in New Zealand. The recommendations for dosage and administration of zinc salts have been outlined in AgLink FPP 496.(5 Towers, N.R. and Smith, B.L. 1983. AgLink FPP 496. Ministry of Agriculture and Fisheries, Wellington,  [Google Scholar]) For sheep the recommended dose of zinc oxide is 300 mg/kg daily but for prophylaxis it is suggested that a week's accumulated dose (i.e. 210 mg/kg) may be given as a single dose and that this is almost as effective as daily dosing and certainly more practical.     

Toxicity of zinc in ruminants in relation to facial eczema

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The toxicity of zinc salts to ruminants has been studied by Ott et al (4) Ott, E. A., Smith, W. H., Harrington, R. B. and Beeson, W. M. 1966. Zinc toxicity in ruminants. I. Effect of high levels of dietary zinc on gains, feed consumption and feed efficiency of lambs. J. Anim. Sci., 25: 414–481. [Web of Science ®] , [Google Scholar] (5) Ott, E. A., Smith, W. H., Harrington, R. B. and Beeson, W. M. 1966. Zinc toxicity in ruminants. II. Effects of high levels of dietary zinc on gains, feed consumption and feed efficiency of beef cattle. J. Anim. Sci., 25: 419–423. [Web of Science ®] , [Google Scholar] (6) Ott, E. A., Smith, W. H., Harrington, R. B., Stob, M., Parker, E. H. and Beeson, W. M. 1966. Zinc toxicity in ruminants. III. Physiological changes in tissues and alterations in rumen metabolism in lambs. J. Anim. Sci., 25: 424–431. [Web of Science ®] , [Google Scholar] (7) Ou, E. A., Smith, W. H., Harrington, R. B., Parker, H. E. and Beeson, W. M. 1966. Zinc toxicity in ruminants. IV. Physiological changes in tissues of beef cattle. J. Anim. Sci., 25: 432–428.  [Google Scholar] and others (3) Miller, W. J., Clifton, C. M., Fowler, P. R. and Perkins, H. F. 1965. Influence of high levels of dietary zinc on zinc in milk, performance and biochemistry of lactating cows. J Dairv Sci., 48: 450–453.  [Google Scholar] (16) Zurcher, T. D. 1970. “A study of the zinc requirement of beef cattle”. In PhD Thesis, Purdue University.  [Google Scholar] (2) Feaster, J. P., Hansard, S. L., McCall, J. T., Skipper, F. H. and Davis, G. K. 1954. Absorption and tissue distribution of radio zinc in steers fed high-zinc rations. J Anim. Sci., 13: 781–788.  [Google Scholar] (12) Thompson, A., Hansard, S. L. and Bell, M. C. 1959. The influence of aluminium and zinc upon absorption and retention of calcium and phosphorous in lambs. Anim. Sci., 18: 187–197.  [Google Scholar] (9) Rosenberger, G. and Gruender, H. D. 1975. “Experiments on the toxicity of zinc dusts in cattle”. In 20th World Veterinary Congress Summaries Vol. 2 Thessaloniki Greece 920–921.  [Google Scholar]. In much of this work zinc has been incorporated in the feed, a situation more applicable to intensive feedlot farming rather than the New Zealand pastoral situation, or the zinc has been fed for limited periods of time with the possibility that the full potential of zinc for causing toxicity has not been realised.     

Acute enteritis and deaths in sheep from Salmonella hindmarsh associated with oral dosing with zinc oxide

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Madam:– The administration of zinc salts to sheep at the time they are exposed to spores of Pithomyces chartarum will reduce the amount of liver damage from the mycotoxin contained in these spores.(7 Smith, B.L., Embling, P.P., Towers, N.R., Wright, D.E. and Payne, E. 1977. The protective effect of zinc sulphate in experimental sporidesmin poisoning of sheep. N.Z. vet. J., 25: 124–127. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar])(10 Towers, N.R., Smith, B.L., Wright, D.E. and Sinclair, D.P. 1975. Preventing facial eczema by using zinc. Proc. Ruakura Farmers Conference 1975, : 57–61.  [Google Scholar])(11 Towers, N.R., Wright, D.E., Aitken, W.M., Smith, B.L., Sim, A.L. and Sinclair, D.P. 1976. Zinc and facial eczema. Proc. Ruakura Farmers Conference 1976, : 65–68.  [Google Scholar]) It is a recommended practice in facial eczema susceptible areas of New Zealand.(9 Towers, N.R. and Smith, B.L. 1983. Facial eczema. Zinc dosing for prevention. Revised recommendations 1984, AgLink FPP 496 end revise [Google Scholar]) We wish to report a suspected outbreak of salmonellosis that occurred only in a ZnO-dosed group of trial animals and suggest that there may be an association between ZnO administration and salmonellosis.     

Porcine parvovirus infection in a commercial piggery

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Madam:– We have recently been involved in a consultative role with a 60-sow commercial piggery. Over the year preceding the incident recorded here, this unit had approximately doubled in size by the purchase of improved large white gilts. An infertility problem involving irregular returns to service and small litter sizes was first noted around Christmas 1984. In early January 1985 all the adult stock were bled and serological tests undertaken. There was no evidence of infection with Aujeszky's disease virus or leptospires, but 42 sows had haemagglutination inhibition (HI) titres(2 Joo, H.O., Donaldson-Wood, C. and Johnson, R.H. 1976. A standardised haemagglutination inhibition test for porcine parvovirus antibody. Aust. vet. J., 52: 422–424.  [Google Scholar]) of >320 against porcine parvovirus (PP), and were considered to have been actively infected. (1 Johnston, R.H., Donaldson-Wood, C., Joo, H.O. and Allender, U. 1976. Observations on the epidemiology of porcine parvovirus. Aust. vet. J., 52: 80–84.  [Google Scholar]) Seventeen other gilts and sows in their second pregnancy had titres ?320 and were considered to be still susceptible to infection. These animals were bled again 75 days later and HI tests on the paired sera showed that 15 of the 17 had now scroconverted (minimum titre 1,280). Eleven of these animals were in early to mid-pregnancy during the period of seroconversion. Five of these animals subsequently failed to farrow, and the remaining six produced a mean of only 6.5 (S.D. 2.8) live piglets at birth. In contrast the two animals which did not seroconvert, and four other previously infected gilts with HI titre of >10,240 at the first bleeding, produced a mean of 9.8 (S.D. 1.7) live piglets. This was considered a satisfactory live birth rate for this age group, and was significantly higher (Student's t-test; P<0.05) than for the six sows which seroconverted and produced live pigs.     

Experimental Ostertagia infection of sheep: Pathology following a single high dose of larvae

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Poisoning of cattle and sheep with superphosphate where the fertilizer was stored within reach of the animals has been reported by Romanenko (1954 Romanenko, K. L. 1954. Poisoning of farm animals with superphosphate. Veterinariya, 31(8): 52–52.  [Google Scholar]). In New Zealand losses of pregnant and lactating ewes grazing pastures topdressed with phosphatic fertilizers have been recognixed for several years, and records kept since 1965 show that 39 outbreaks have been reported to Ruakura Animal Health Laboratory (P. J. O'Hara, pers. comm.). Swan and McIntosh (1952 Swan, J. B. and Mcintosh, I. G. 1952. The toxicity of North African phosphate and superphosphate to milking cows. Proc. N.Z. Soc. Anim. Prod., 12: 83–88.  [Google Scholar]) have described the toxicity to dairy cows of grazing pasture topdressed with North African phosphate and superphosphate. The toxic factor was later identified as fluorine (Animal Research Division of the New Zealand Department of Agriculture Reports 1952–3, p. 28; 1953–4, p. 34; 1954–5, p. 35). Phosphatic fertilizers are known to contain 1 to 4% fluorine (Caro, 1964 Caro, J. H. 1964. Superphosphate. Its History, Chemistry and Manufacture, Washington, D.C.: USDA arid TVA. In [Google Scholar]), and the danger of poisoning stock with fluorine in untreated phosphates used as feed supplements has been described by many authors (Emmerling, 1902 Emmerling, A. 1902. Warning against the use of toxiccalcium phosphate in feed. Milchzeitung, 31: 728–728.  [Google Scholar]; Dammann and Manegold, 1904 Dammann, C. and Manegold, O. 1904. Poisonings by fluorine-containing calcium phosphate used as a feed supplement. Dt tierarztl. Wscht., 12: 129–131.  [Google Scholar]; Gardiner, 1930 Gardner, U. R. 1930. Agricultural Experiment Station Report, 201–201. Michigan State College. June 30 [Google Scholar]; Phillips et al., 1934 Phillips, P. H., Hart, E. B. and Bohstedt, G. 1934. Chronic toxicosis in dairy cows due to the ingestion of fluorine. Wisconsin Univ. Agric. Exp. Sta. Res. Bull., 123: 1–3.  [Google Scholar]; Hatfield et al., 1942 Hatfield, J. D., Shrewsbury, C. L. and Doyle, L. P. 1942. The value of rock phosphate as a supplement for sheep. J. Anim. Sci., 1: 59–59.  [Google Scholar]; Udall, 1947 Udall, D. H. 1947. The Practice of Veterinary Medicine, 5th ed., 724–725. Ithaca, New York: Udall.  [Google Scholar]; Fincher, 1952 Fincher, M. G. 1952. Fluorine Poisoning in Cattle. Report of the New York State Veterinary College of Cornell University 1950–51, : 34–34.  [Google Scholar]; Harris et al., 1952 Harris, L. E., Baird, G. T., Bateman, G. Q., Binns, W., Draper, C. I., Greenwood, D. A., Henderson, G. R., Jenkins, W. R., Rich, L. H., Thorne, D. W. and Wann, F. B. 1952. Recommended practices to reduce fluorosis in livestock and poultry. Utah State Agric. Coll. Agric. Exp. Sta. Circ., : 130–130.  [Google Scholar]; Crampton, 1954 Crampton, E. W. 1954. Fluorosis in dairy cows traced to rations. Can. Milling and Feed, 35(12): 24–26.  [Google Scholar]; Dale and Crampton, 1955 Dale, G. D. and Crampton, E. W. 1955. Observations on chronic fluorosis in dairy cattle. Can. J. comp. Med., 19: 6–16.  [Google Scholar]; Snook, 1962 Snook, L. C. 1962. Rock phosphate in stock feeds. The fluorine hazard. Aust. vet. J., 38: 42–47.  [Google Scholar]; Rek, 1967 Rek, L. 1967. Tolerance to dietary fluorine by farm animals. Agrochemia, 7: 334–336.  [Google Scholar]; Agarwala et al, 1971 Agarwala, O. N., Nath, K. and Mahadevan, V. 1971. Use of superphosphate as a phosphorus supplement for lambs — effect on calcination or supplementation with oral cobalt or parenteral vitamin B₁₂. J. agric. Sci., Camb., 77: 467–471.  [Google Scholar]).     

Isolation of Leptospira hardjo from the opossum (Trichosurus vulpecula)

Isolation of leptospira hardjo from the opossum (trichosurus vulpecula)

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Sir, — In 1971 and 1972 the Department of Health and the Ministry of Agriculture and Fisheries conducted surveys on the incidence of leptospirosis among fanners and their stock on the Hauraki Plains. As a result, Leptospira hardjo was identified for the first time in New Zealand, being isolated from humans (Christmas et al., 1974 Christmas, B. W., Till, D. G. and Bragger, Judith M. 1974. Dairy farm fever in New Zealand: Isolation of L. pomona and L. hardjo from a local outbreak. N. Z. med. J., 79: 904–906. [PubMed] , [Google Scholar]) and from dairy cattle (Lake, 1973 Christmas, B. W., Till, D. G. and Bragger, Judith M. 1974. Dairy farm fever in New Zealand: Isolation of L. pomona and L. hardjo from a local outbreak. N. Z. med. J., 79: 904–906. [PubMed] , [Google Scholar]). Evidence to date suggests that most human infections in New Zealand, whether of L. hardjo or of other serotypes, are contracted while milking.     

Fleece derangement of merino sheep infested by the itch mite Psorergates ovis

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Fleece derangement, characterized by matted chewed wool in a region accessible to the sheep's mouth — i.e., behind a line approximately from elbow to hip, — indicates a typical behavioural response by sensitive sheep infested with Psorergates ovis. The condition was recorded by Bekker (1928) Baker, J. A. F. 1968. Some clinical aspects of itch mite (Psorergates ovis) infestation of Merino sheep in South Africa. Jl S. Afr. vet. med Ass., 39: 53–68.  [Google Scholar] long before the mite was found (Carter, 1941 Bekker, J. G. 1928. Undescribed skin diseases of sheep in South Africa. Jl S. Afr. vet. med Ass., 1: 51–57.  [Google Scholar]; Womersley 1941 Carter, H. B. 1941. A skin disease of sheep due to an ectoparasitic mite, Psorergates ovis Womersley 1941. Aust. vet. J., 17: 193–201.  [Google Scholar]). Fleece derangement is seen easily at flock inspection and so is used as anindication of P. ovis infestation in a flock, though Baker (1968) Graham, N. P. H. 1943. Some observations on the bionomics of the itch mite (Psorergates ovis) of sheep and its control with lime sulphur dips. J. Coun. scient. ind. Res. Aust., 16: 206–214.  [Google Scholar] showed that a greater proportion of sheep in which heavy skin scurf was present, with or without fleece derangement, may be infested. Inspecting individual sheep closely for scurf is slow, while examining skin scrapings limits the number of sheep that can be inspected to less than about twenty per day, so the ready convenience of observing fleece derangement favours its use.     

Cutaneous antigen-antibody reactions in the sheep

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It is clear that the early permeability response in the sheep that follows chemical and thermal injury, is mediated by histamine (Lancaster and Vegad, 1967 Lancaster, M. C. and Vegad, J. L. 1967. Suppression of the early inflammatory response in the sheep by strophanthin G. Nature, Lond., 213: 840–841.  [Google Scholar]; Vegad, 1971a Vegad, J. L. 1971a. Effect of thermal injury on vascular permeability in the sheep. Indian J. exp. Biol., 9: 111–112.  [Google Scholar], b Vegad, J. L. 1971b. Leucocyte emigration following intradermal injection of histamine, 5-hydroxytrypta-mine and bradykinin in the sheep. Indian J. exp Biol., 9: 113–114.  [Google Scholar]). This is similar to the situation in the rat and the guinea-pig (Spector and Willoughby, 1965 Spector, W. G. and Willoughby, D. A. 1965. The Inflammatory Process, Edited by: Zwiefach, B. W., Grant, L. and Mc-Cluskey, R. T. 427–427. New York: Academic Press. In [Google Scholar]). In contrast to the situation in the rat and the guinea-pig, various nucleosides (Vegad, 1970c Vegad, J. L. 1970c. Effect of hyaluronidase and nucleosides on vascular permeability in sheep and its suppression by mepyramine maleate. Indian J. exp. Biol., 8: 141–142.  [Google Scholar]), hyaluronidase (Vegad, 1970c Vegad, J. L. 1970c. Effect of hyaluronidase and nucleosides on vascular permeability in sheep and its suppression by mepyramine maleate. Indian J. exp. Biol., 8: 141–142.  [Google Scholar]), 5-hydroxytryptamine, turpentine-induced pleural exudates and the lymph node cell extracts also release histamine in the sheep skin (Vegad, 1967 Fischel, E. E. and Kabat, E. A. 1947. Quantitative study of Arthus phenomenon induced passively in rabbit. J. Immun., 55: 337–343.  [Google Scholar]). From these results it was thought possible that cutaneous antigen-antibody reactions might also release histamine in the sheep, and this possibility has been investigated in the present experiments.     

Impact of daylength on the productivity of two commercial broiler strains

1. The impact of daylength on productivity in male and female broilers of two genotypes was studied in two replicated experiments. In each experiment, four lighting programs (14L:10D (14L), 17L:7D (17L), 20L:4D (20L) and 23L:1D (23L)) were used to study the relationships between productivity and daylength in two genotypes and both genders.

2. General Linear Model analysis was used to test for differences in daylength, genotype, gender and their interactions, and regression analysis to define relationships between productivity and daylength in experiment one and daylength differences in experiment two.

3. In experiment one, body weights at d 32 (P?=?0·002) and d 39 (P?=?0·011) were related in a quadratic fashion to daylength, with the heaviest birds raised under 20L. The growth curve at d 49 was similar in shape, and body weights under both 17L and 20L were significantly higher than under 14L and 23L (P? 4. Feed consumption was highest to d 39 or d 49 under 20L, and birds under 23L ate as much (d 39) or less feed (d 49) than under 17L.

5. Gain-to-feed efficiency (FCR) responded in a quadratic fashion, with maximum efficiency observed under the shortest daylength.

6. Mortality increased linearly with daylength for all time periods in both experiments.     

Muscular dystrophy in pups

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Muscular dystrophies (white muscle disease) do not appear tot be commonly encountered in the dog. Elvehjem et al. (1944) Cocks, L. V. and van Rede, C. 1966. Laboratory Handbook for Oil and Fat Analysts, 109–109. New York: Academic Press.  [Google Scholar] described the occurrence of a vitamin E-responsive muscular dystrophy in pups born to, bitches fed evaporated milk fortified with iron, copper manganese and cold liver oil. In New Zealand Money et al. (1971) Elvehjem, C. A., Gonce, J. E. and Newell, G. W. 1944. The effect of vitamin E on reproduction in dogs on milk diets. J. Pediatrics, 24: 436–441.  [Google Scholar] recorded an, advanced cardiac myopathy in a 2-week-old pup from a litter of three all of which had died after exhibiting signs of respiratory distress. Response to vitamin E treatment in a subsequently similar clinical disorder suggests that the pathological condition was probably due to a vitamin E deficiency Manktelow (1963) Hartley, W. J. 1967. Symposium: Selenium in Biomedicine, Westport, Conn.: O. H. Muth, Avi. Chapter 5 [Google Scholar], however, suggested that the disorders he had seen were possibly selenium-respoasive myopathies since they occurred in an area where ovine selenium-responsive disorders also occurred. His cases included an adult working dog that had lost the use of its hindquarters and two litters of young pups in which myocardial necrosis was the main lesion. This note is to record the occurrence of muscular dystrophy in a litter of four crossbred pups born to a bitch with a previously good breeding history.     

Congenital pyloric stenosis in two kittens corrected by pyloroplasty

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Rural veterinary practice faces difficulties in many parts of the world. Falling farm incomes and increasing costs have sometimes resulted in reduced use of veterinary services. There seems to be widespread agreement that an increased emphasis on preventive medicine would improve the situation for both the farmer and his veterinarian. There appear to be no commonly agreed formal criteria for the development and evaluation of health programmes, either in human or veterinary medicine, but increasing attention is being paid to the problem(1) Anon Statistical indicators for the planning and evaluation of public health programmes: 11th report of the World Health Organisations expert committee on health statistics W. H. O. Tech. Reports No. 365 1971  [Google Scholar] (12) Morris, R. S. 1969. Assessing the ecnomic value of veterinary services to primary industries. Aust. vet. J., 45: 295–300.  [Google Scholar] (14) Morris, R. S. 1975. Criteria for the design and evaluation of bovine mastitis control systems. International Dairy Federation Proceedings, 85: 395–409. In [Google Scholar] (15) Schulberg, H. C., Sheldon, A. and Baker, F., eds. 1970. Program evaluation in the health fields, N.Y.: Behavioural Publications.  [Google Scholar], In some ways the evaluation of animal health programmes should be the easier, for there are fewer ethical problems and economic criteria are of paramount importance in rural practice.     

leptospira interrogans serovar hardjo vaccination against leptospira interrogans serovar balcanica infection

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Sir, — Leptospira interrogans serovar balcanica is now recognised as a widespread infection among opossums in New Zealand ⁽²⁾ Hathaway, S. C, Blackmore, D. K. and Marshall, R. B. 1978. The serologic and cultural prevalence of Leptospira interrogans serovar balcanica in opossums (Trichosurus vulpecula) in New Zealand. J. Wild Dis., 14: 345–350. [PubMed], [Web of Science ®] , [Google Scholar] and the possibility of domestic stock acting as accidental hosts has recently been demonstrated. ⁽³⁾ Mackintosh, C. G., Marshall, R. B. and Blackmore, D. K. 1980. Leptospira interrogans serovar balcanica in cattle. N.Z. vet. J., 28: 268–268. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar] With the recent development of hardjo vaccines ⁽¹⁾ Flint, S. H. and Liardet, D. M. 1980. A Trivalent leptospiral vaccine with emphasis on a Leptospira interrogans serovar hardjo component to prevent leptospiruria. N.Z. vet. J., 28: 263–266. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar] ⁽⁴⁾ Marshall, R. B., Broughton, E. S. and Hellstrom, J. S. 1979. Protection of cattle against natural challenge with Leptospira interrogans serovar hardjo using a hardjo - pomona vaccine. N.Z. vet. J., 27: 114–116. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar] for controlling infection with this serovar in the maintenance hosts, stock could be left vulnerable to infection with other prevalent serovars such as balcanica.     

The brown dog tick (Rhipicephalus sanguineus) on an imported dog

Abstract

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Sir, — We wish to record the presence of the tick Rhipicephalus sanguineus on a dog imported from Australia. This tick is mainly parasitic on dogs although on rare occasions it has been collected from non-canine hosts (Roberts, 1965 Roberts, F. H. S. 1965. The taxonomie status of the species of the genera Rhipicephalus (Koch) and Boophilus (Curtice) occurring in Australia. Aust. J. Zool., 13: 491–523.  [Google Scholar]). Experimentally it has been shown capable of transmitting a wide variety of serious diseases but its role as a natural vector of many of them is unknown. In Australia it has been demostrated as being naturally infected with Coxiella burnetii (Smith, 1942 Smith, D. J. W. 1942. Studies on the epidemiology of Q Fever. Aust. J. exp. Biol. med. Sci., 20: 295–296.  [Google Scholar]) and is recorded from all continents and some oceanic islands lying between latitudes 50°N and 36°S (Roberts, 1970 Roberts, F. H. S. 1970. Australian ticks, 87–87. CSIRO.  [Google Scholar]). Auckland falls within this boundaries and therefore it is not unreasonable to suggest that R. sanguineus could become established in New Zealand.     

Prevalence of antibodies to infectious laryngotracheitis virus in poultry in New Zealand

Abstract

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Infectious laryngotracheitis (ILT) is an acute respiratory disease of fowls which was first reported from the U.S.A. by May and Tittsler (1925) Adlakha, S. C. 1966. A serological investigation to determine respiratory infections of poultry in India. Avian Dis., 10: 401–404.  [Google Scholar]. Both severe acute forms with high mortality and chronic enzootic forms with low mortality have been described, and the earlier literature was reviewed by Jordan (1966) Chang, P. W., Yates, V. J., Dardiri, A. H. and Fry, D. E. 1960. Some observations of the propagation of infectious laryngotracheitis virus in tissue culture. Avian Dis., 4: 384–390.  [Google Scholar]. In New Zealand ILT virus was first isolated in 1957 (Webster, 1959 Hitcher, S. B., Shea, C. A. and White, P. G. 1958. Studies on a serum neutralization test for the diagnosis of laryngotracheitis in chickens. Avian Dis., 2: 258–269.  [Google Scholar]).     

The carrier state in cattle in foot-and-mouth disease

Abstract

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The possibility of cattle recovering from foot-and-mouth disease and subsequently transmitting it to susceptible animals has been a matter of speculation for some considerable time. This has been particularly so in outbreaks of the disease in which the origin could not be explained in any other way. To cite a few instances, during the winter of 1893–4 in Denmark, foot-and-mouth disease reappeared on four large farms on which outbreaks had taken place from 6 to 12 months previously. In each case, it was observed that only newly purchased calves and cattle introduced since the previous outbreak became affected. The disease was stamped out by killing all the new cattle, but, in spite of this, a third outbreak occurred 12 months after the second outbreak on one of the farms when new cattle were again introduced, affecting only the new animals (Anon., 1901 Anon. Foot-and-mouth disease J. comp. Path. 1901 14 65 68  [Google Scholar]; Bang, 1912 Bang, B. 1912. Foot-and-mouth disease. J. comp. Path., 25: 1–15.  [Google Scholar]). The source of infection could not be determined, particularly as the rest of the country had been free of the disease during the period.     

Exsheathment of infective larvae of Cooperia curticei

Abstract

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Although exsheathment of the infective larvae of many strongylate nematode parasites of ruminants has been studied (Rogers, 1966 Rogers, W. P. 1966. “Exsheathment and hatching mechanisms in helminths”. In Biology of Parasites, Emphasis on Veterinary Parasites, Edited by: Soulsby, E. J. L. 33–39. New York and London: Academic Press. In [Google Scholar]), that of Cooperia curticei larvae has not. By analogy with other trichostrongylid species inhabiting the small intestine, they would be expected to exsheath in response to conditions provided by the abomasum, perhaps, as with Trichostrongylus colubriformis, with a potentiating effect of bile salts in the small intestine (Mapes, 1972 Mapes, C. J. 1972. Bile and bile salts and exsheathment of the intestinal nematodes Trichostrongylus colubriformis and Nematodirus battus. Int. J. Parasit., 2: 433–438.  [Google Scholar]). It was decided to see if C. curticei larvae exsheathed as expected; no attempt was made to define precisely the conditions necessary for exsheathment but rather to establish the site at which the stimulus is received.     

Some observations on reproductive performance in selected commercial beef herds

Abstract

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Although the opinion has been expressed (Andrews, 1971 Andrews, E. D. 1971. Cobalt deficiency in sheep and cattle. N.Z. Dept. Agric. Bull., : 180–180.  [Google Scholar]) that cobalt deficiency among cattle has virtually disappeared in New Zealand and that specimens for laboratory examination are rarely required, 15 to 20% of the liver samples submitted by veterinarians to the Animal Health Reference Laboratory for vitamin B₁₂ assay are from cattle. Diagnostic criteria for cobalt (vitamin B₁₂) deficiency cy have long been established for sheep but not for cattle In view of the continuing requests for vitamin B₁₂ analyses on bovine livers, it was desirable to establish normal values for clinically normal cattle so that results of routine diagnostic analyses could be more readily interpreted.     

An indirect haemagglutination test for the detection of Vibrio fetus antibodies

Abstract

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Indirect bacterial haemagglutination was first reported by Keogh et al. (1947 Keogh, E. V., North, E. A. and Warburton, M. F. 1947. Nature (Lond.), 160: 63–63.  [Google Scholar]). It depends on the adsorption of bacterial antigens to the surface of red blood cells rendering them agglutinable in the presence of homologous bacterial antibody. A comprehensive review by Neter (1956 Neter, E. 1956. Bact. Rev., 20: 166–166.  [Google Scholar]) summarizes the methods used and results achieved with various bacterial antigens. Biberstein (1955 Biberstein, E. L. 1955. Cornell Vet., 46: 144–144.  [Google Scholar]) used an adaption of Neter's method of antigen preparation in studying the antigenic relationships of Vibrio species. The objects of the present studywere to determine whether an erythrocyte adsorbable antigen could be obtained from Vibrio fetus, to compare its sensitivity with a formalinized bacterial antigen, and to study its application to the detection of antibodies in bovine vaginal mucus. The work will be described in two sections, the first dealing with the preparation and properties of sheep red cells modified with material derived :from V. fetus, and the second with the detection of antibodies in bovine vaginal mucus.     

Polymerase chain reaction (PCR) survey for rickettsias and bartonellas in ticks from New Zealand

Abstract

Extract

New Zealand is remarkable for the few species of tick that occur in the country and an apparent absence of tick-borne diseases. There is, however, only a lack of reports of locally-acquired infections which indicates tick-borne spotted fever group (SFG) rickettsias, ehrlichias, anaplasmas and bartonellas do not occur in the country (Roberts et al 2001 Roberts, S, Hill, P, Croxson, M, Austin, P, McKay, J and Ellis-Pegler, R. 2001. The evidence for rickettsial disease arising in New Zealand. New Zealand Medical Journal, 114: 372–374.  [Google Scholar]). To provide more definitive information, we conducted a PCR survey on ticks from New Zealand.