bluuebunny/crossref_metadata_2025 huggingface dataset:
Progressive ataxia associated with degenerative thoracic myelopathy in Merino sheep
Authors: HARPER PAW , PLANT JW , WALKER KH , TIMMINS KG
Published: March 2008

SUMMARY A neurological disorder in Merino sheep, characterised clinically by progressive posterior ataxia and microscopically by Wallerian degeneration in thoracic segments of the spinal cord, is described. Animals of both sexes were affected, with the earliest onset of disease being at 5 months of age. Most affected animals died before 2 years of age. The clinical, pathological and epidemiological features suggest that this degenerative thoracic myelopathy is a previously unrecognised entity differing from other reported causes of ataxia in sheep in Australia.
The effects of Arctotheca calendula (capeweed) on digestive function of sheep
Authors: PETHICK DW , CHAPMAN HM
Published: March 2008

SUMMARY The effects of Arctotheca calendula (capeweed) on digestive function in the rumen, caecum and colon of sheep were studied. Three groups of 2‐year‐old Merino wethers were compared: 13 grazing capeweed‐free pasture for 23 days; 8 fed 700 g of lucerne hay dally for 18 days, and 13 fed 6 kg of freshly cut capeweed (dry matter 11.3%) daily for 7 days. Capeweed did not cause diarrhoea and based on measurements of products of fermentation In the rumen, the plants were as nutritious as pasture containing grasses and clovers. The main disadvantage of capeweed in this single feeding trial was that sheep eating it lost body weight due to their inability, or lack of incentive, to consume enough dry matter.
Cloning and sequencing of the ovine gamma‐interferon gene
Authors: RADFORD AJ , HODGSON ALM , ROTHEL JS , WOOD PR
Published: March 2008

SUMMARY Cytokines are major modulators of the immune system of all animals. The cloning and expression of recombinant cytokine genes have permitted the analysis of their immune function and role in the control of the immune response to disease and vaccination. While human, murine, and bovine genes have been cloned and sequenced, the cloning of ovine cytokine genes has not yet been reported. As sheep are of dominant economic importance to the Australian farming industry, it is of significance to clone and express these genes to facilitate the development of new and better vaccines and pharmaceuticals. We have initially selected ovine gamma‐interferon (γ‐IFN) as a target cytokine gene. By the use of the polymerase chain reaction (PCR), using primers based on the bovine gamma‐interferon sequence, we have amplified the ovine gamma‐interferon gene from crude messenger RNA extracted from lymphocytes. After cloning and DNA sequencing the gene, we found that ovine γ‐IFN is 93% identifical to bovine γ‐IFN in amino acid sequence. This result indicates that the PCR method will be a rapid and efficient means for cloning other ovine cytokine genes.
The serological responses of chickens to mass vaccination with a live V4 Newcastle disease virus vaccine in the field and in the laboratory 1. Meat chickens
Authors: BELL IG , NICHOLLS PJ , NORMAN C , COOPER K , CROSS GM
Published: March 2008

SUMMARY Meat chickens on commercial broiler farms were vaccinated once at 1 to 15 days of age with a live V4 Newcastle disease virus (NDV) vaccine administered by drinking water, aerosol or coarse spray. Hatchmates were housed and similarly vaccinated in laboratory isolation pens. Samples of birds were bled at weekly to fortnightly intervals and the serums tested for haemagglutination inhibiting antibody to NDV. Log2 mean titres of up to 6.26, and assumed protection levels (based on the percentage of birds with log2 titres of 4 or greater) of up to 89%, were obtained in field trials within 4 weeks of vaccination. Differences were observed between the results obtained from parallel field and laboratory trials. The presence of maternal NDV antibody reduced the response to vaccination. The results show that this V4 vaccine can produce an adequate serological response following mass administration to Australian meat chickens housed under commercial conditions.
The serological responses of chickens to mass vaccination with a live V4 Newcastle disease virus vaccine in the field and in the laboratory 2. Layer pullets
Authors: BELL IG , NICHOLLS PJ , NORMAN C , COOPER K , CROSS GM
Published: March 2008

SUMMARY Layer chickens on a commercial started pullet farm were vaccinated once at 31 to 52 days of age by drinking water or aerosol with live V4 Newcastle disease virus (NDV) vaccine. Flockmates which had been rehoused in laboratory isolation pens shortly beforehand were similarly vaccinated. Samples of birds were bled at intervals and the serums tested for haemagglutination inhibiting antibody to NDV. Log2 mean titres of up to 4.88 and assumed protection levels (based on the percentage of birds with log2 titres of 4 or greater) of up to 81%, were obtained in the field trials within 4 weeks of vaccination. A subsequent laboratory trial further compared the response of different breeds of chicken to different routes of vaccination. Differences were observed between breeds, routes of vaccination, and parallel field and laboratory trials. The results show that this V4 vaccine can produce an adequate serological response following mass vaccination of Australian layer pullets housed under commercial conditions, and that care should be exercised in extrapolating results obtained under laboratory conditions.
Natural infection of broiler breeder chickens with endemic apathogenic Newcastle disease virus and their subsequent response to vaccination with a live V4 Newcastle disease virus vaccine
Authors: BELL IG , NICHOLLS PJ , NORMAN C , CROSS GM
Published: March 2008

SUMMARY Flocks of broiler breeder chickens housed on a commercial farm were monitored from 13 w of age for natural infection with endemic lentogenic Newcastle disease virus (NDV). Seroconversion was first detected at 17 w. By 24 w, all 8 flocks had achieved peak log2 mean haemagglutination inhibiting antibody titres of up to 4.8. Antibody titres then declined and rose again over several months, suggesting cyclic reinfection with NDV. A lentogenic NDV indistinguishable from V4 was isolated from the cloaca of one bird at 18 weeks of age.

At 54 weeks of age, 6 of 8 flocks were vaccinated en masse with live V4 NDV vaccine, 3 flocks by drinking water and 3 flocks by aerosol. All flocks were serologically monitored for a further 8 w. Drinking water vaccination induced an anamnestic response in 3 flocks, showing that flocks with pre‐existing active immunity to NDV may be successfully vaccinated with V4. However, in all aerosol vaccinated flocks, the procedures failed to induce a response different to that observed in unvaccinated flocks. The serological response to vaccination was greater in sires than in dams.
The resistance of meat chickens vaccinated by aerosol with a live V4 Newcastle disease virus vaccine in the field to challenge with a velogenic Newcastle disease virus
Authors: BELL IG , NICHOLLS PJ , NORMAN C. , IDERIS AINI , CROSS GM
Published: March 2008

SUMMARY Meat chickens housed on a commercial broiler farm in Australia were vaccinated once at 10 to 11 days‐of‐age by aerosol with live V4 Newcastle disease virus (NDV) vaccine. Groups of vaccinated and unvaccinated birds were flown to Malaysia, where they were challenged with a virulent strain of NDV. Survival rates in vaccinated chickens challenged 7, 14, 21 or 31 d after vaccination were 0.47, 0.77, 0.97 and 0.92, respectively. All unvaccinated chickens died due to Newcastle disease (ND) following challenge. Chickens in Australia and Malaysia were bled and the serums tested for haemagglutination‐inhibiting (HI) antibody to NDV. Many vaccinated birds with no detectable antibody, and all birds with a log2 titre of 2 or greater, survived challenge. The results showed that this V4 vaccine induced protective immunity in a significant proportion of chickens within 7 d of mass aerosol vaccination. This early immunity occurred in the absence of detectable circulating HI antibody. Non‐HI antibody mediated immunity continued to provide protection up to 31 d after vaccination. Almost all vaccinated birds were protected within 3 w of vaccination. It is concluded that the V4 vaccine is efficacious and could be useful during an outbreak of virulent ND in Australia.
Immunisation against ovine caseous lymphadenitis: comparison of Corynebacterium pseudotuberculosis vaccines with and without bacterial cells
Authors: EGGLETON DG , MIDDLETON HD , DOIDGE CV , MINTY DW
Published: March 2008

SUMMARY Sheep were immunised with Corynebacterium pseudotuberculosis vaccines prepared from cell‐free toxoid or from toxoid with formalin‐killed cells of C pseudotuberculosis added. Resistance of sheep to infection was tested 6 months after immunisation by inoculation with caseous lymphadenitis pus. The outcome was assessed 3 months later by slaughter and inspection of the sheep for lesions of caseous lymphadenitis. Immunised sheep were adequately protected against infection as shown by a significant reduction in the number of sheep exhibiting lesions compared with control sheep, and by fewer abscesses in affected vaccinated sheep than in affected control sheep. The protective potency of the vaccines was not improved by the inclusion of cells of C pseudotuberculosis.
Chronic cervical compressive myelopathy in horses: patterns of astrocytosis in the spinal cord
Authors: YOVICH JV , GOULD DH , LeCOUTEUR RA
Published: March 2008

SUMMARY The distribution and morphology of fibrous astrocytes in the cervical spinal cord of normal horses and horses with chronic compressive myelopathy were demonstrated using immunohistochemical staining for glial fibrillary acidic protein.

In the spinal cord from normal horses, astrocytes with stellate cell bodies and short processes were irregularly distributed in grey matter. In the white matter, their cell bodies were small and angular in areas adjacent to grey matter and larger and more stellate‐shaped in the subpial area. Astrocyte processes were fine, and evenly distributed in a predominantly radial pattern in transverse sections of cord.

Gliosis was marked in the spinal cords of horses with cervical compressive myelopathy. In the grey matter at the level of compression astrocytes were often enlarged and rounded, with short, blunt processes, but the gliosis was generally mild. In the white matter, gliosis was obvious in areas of nerve fibre swelling and degeneration at the level of compression and in areas of ascending and descending Wallerian degeneration. The fine radial pattern of astrocyte fibres was replaced by a dense, irregular arrangement. Gliosis persisted in the cords of chronically affected horses after active nerve fibre degeneration had subsided. The areas of gliosis coincided with the areas of Marchi staining for degenerating myelin and with areas of myelin loss in osmium tetroxide post‐fixed tissue. Histological observations were consistent with astrocytes replacing areas of extracellular space that remained after nerve fibre degeneration. It is concluded that astrocytic gliosis is a prominent and persistent alteration of the spinal cord of horses with chronic cervical compressive myelopathy.
Meningoencephalitis and other conditions associated with Histophilus ovis infection in sheep
Authors: PHILBEY AW , GLASTONBURY JRW , ROTHWELL JT , LINKS IJ , SEARSON JE
Published: March 2008

SUMMARY Histophilus ovis was isolated from 29 sheep in 20 flocks and 2 artificial insemination (AI) centres in southern New South Wales from 1984 to 1990. The clinical and pathological findings were consistent with previous reports and included polyarthritis (7 flocks), epididymo‐orchitis (5), meningoencephalitis (3), pneumonia (3), septicaemia (2), mastitis (1) and metritis (1). Six sheep had meningoencephailtis, a syndrome not previously associated with H ovis infection in sheep, which was similar pathologically to thromboembolic meningoencephalitis in cattle, caused by the related organism, Haemophilus somnus. H ovis was isolated from the semen of 12‐month‐old rams in a flock that had polyarthritis due to H ovis, in 4‐month‐old ram lambs and from the uterus of a ewe in a flock that had sporadic cases of H ovis septicaemia.
Cross‐protective immunity and the serological classification system for Bacteroides nodosus
Authors: STEWART DJ , VAUGHAN JA , ELLEMAN TC , HOYNE PA , BURNS KJ , DUFTY JH
Published: March 2008

SUMMARY The relationship between the serological classification system for serogroup B and for serogroup H of Bacteroides nodosus and cross‐protection between subgroups within these serogroups was examined. Protection against ovine footrot following vaccination was achieved against other subgroup strains provided sufficient cross‐reactive antibody was induced by shared pilus antigens. Within serogroup B, better cross‐protection against one subgroup was obtained with a pili vaccine than a whole cell vaccine which correlated with higher pilus antibody titres induced by the former. For serogroup H, a lack of cross‐protection and serological reactivity between subgroups was demonstrated, which indicates that the prototype strain of subgroup H2 should be designated a new serogroup.
Thiamin deficiency in cats and dogs associated with feeding meat preserved with sulphur dioxide
Authors: STUDDERT VP , LABUC RH
Published: March 2008

SUMMARY Thiamin deficiency was diagnosed in cats and dogs being fed fresh minced meat, which contained sulphur dioxide as a preservative and less than 0.5 mg/kg thiamin. Thiamin in the meat and in added dietary ingredients, including a supplementary vitamin mixture, was destroyed by the sulphur dioxide.
Oral transmission of transmissible gastroenteritis virus by muscle and lymph node from slaughtered pigs
Authors: COOK DR , HILL HT , TAYLOR JD
Published: March 2008

SUMMARY A study was conducted in the USA to determine whether transmissible gastroenteritis (TGE) virus could be transmitted from carcases of slaughtered pigs. Transmissible gastroenteritis virus was transmitted to 6‐day‐old piglets by dosing with homogenates of muscle and lymph node collected from 500 clinically normal pigs at the time of slaughter. All piglets in 2 separately housed litters showed clinical signs of TGE with 5 piglets dying within 10 d of oral dosing with homogenates. Transmissible gastroenteritis virus was isolated from 2 of these piglets and all piglets developed TGE antibody. Transmissible gastroenteritis virus was not isolated in tissue culture from muscle and lymph node homogenates, but was isolated from 4 (0.8%) of 500 tonsil samples collected from the same pigs. A survey of 250 serum samples provided an estimate of the prevalence of slaughtered pigs with TGE antibody of 34.8% in the sample population. The results indicate that carcases of some pigs from TGE endemic areas contain viable TGE virus, and that there would be a substantial risk of introducing TGE virus into Australia by the importation of uncooked pig meat from these areas.
Field evaluation of a mixture of albendazole sulphoxide and levamisole against Ostertagia and Trichostrongylus spp in sheep
Authors: ANDERSON N. , MARTIN PJ , JARRETT RG
Published: March 2008

SUMMARY The efficacy of a mixture of albendazole sulphoxide and levamisole, 3.6 and 8.25 mg/kg respectively, at single and double dose rates, was compared with the recommended dose rate of each anthelmintic alone. The comparison was conducted on groups of 6 to 14‐week‐old lambs on 22 farms, 16 of which had evidence of multiple resistance to benzimidazole and levamisole.

A single dose of the mixture reduced mean egg counts by 95% on half the farms with multiple resistance and on all the remaining farms. Consequently, the mixture should be included in an assessment of effective anthelmintics on farms to determine Its value for nematode control. A double dose rate of mixture was effective on all but 4 farms.

Reductions caused by the mixture were due to the additive actions of the drugs on 18 of 22 farms; synergistic action was noted on only 3 farms. It was concluded that the mixture of albendazole sulphoxide and levamisole offered many farmers an effective anthelmintic for use in preventive control programs. Recommendations for such programs include annual rotation of effective anthelmintics as a means of delaying selection for drug resistance.
Left‐side displacement of the abomasum in dairy cows at pasture
Authors: JUBB TF , MALMO J. , DAVIS GM , VAWSER AS
Published: March 2008

SUMMARY The presentation of approximately 40 dairy cows affected with left‐side displacement of the abomasum (LDA) per annum In a cattle practice in East Gippsland, Victoria provided an opportunity to conduct a survey and case‐control study of the disease in a grazing environment. The study, Involving 37 dairy cows at pasture, revealed significant differences from the pattern of the disease occurring In the northern hemisphere where cows In older age groups, of larger frame size, higher production and fed high grain rations are at Increased risk.

Affected cows were diagnosed over a 10‐month period and represented approximately 0.06% of the dairy cow population. Most cases were diagnosed In the early lactation period. Evidence for a genetic predisposition was suggested by the discovery that one sire generated a disproportionately large number (9) of the cows with LDA. Although affected cows were average producers in their herds, being a member of a high‐producing herd was a significant risk factor.
The effect of antibody to caseous lymphadenitis in ewes on the efficacy of vaccination in lambs
Authors: Paton MW , Mercy AR , Sutherland SS , Ellis TM , Duda SR
Published: March 2008

SUMMARY The effect of maternal antibody to the toxin of Corynebacterium pseudotuber‐culosls, produced by caseous lymphadenitis (CLA) in ewes or by vaccinating ewes before lambing, on the efficacy of vaccination against CLA In their lambs was examined. Lambs were allocated to treatments according to either the vaccination history of their dam or level of CLA toxin antibody of their dam. They were vaccinated twice using 2 different inoculation regimes and then artificially Infected with CLA organisms. The number of lambs with CLA lesions was assessed at slaughter.

In one experiment high levels of CLA toxin antibody activity in ewes were associated with decreased efficacy of CLA vaccination in their lambs, when lambs were vaccinated at 2 and 8 weeks or 8 and 14 weeks of age. In a second experiment the efficacy of lamb vaccination at 8 and 12 weeks, but not at 14 and 18 weeks of age, was decreased. In sheep flocks with a high prevalence of CLA, vaccinating lambs against CLA at less than 10 weeks of age may not produce optimum protection against CLA in lambs.

There was no difference in Infection rate between lambs from vaccinated and unvaccinated ewes. However, vaccination of lambs at 2 and 8 wks was less effective that vaccination at 8 and 14 weeks, probably due to reduced Immunocompetence In young lambs. In sheep flocks where significant numbers of lambs receive their primary vaccination at less than 3 weeks of age vaccination programmes to control CLA in lambs may be less effective.
Bentonite as therapy for Lantana camara poisoning of cattle
Authors: McKENZIE RA
Published: March 2008

SUMMARY Bentonite was compared with activated charcoal as therapy for lantana poisoning in calves dosed 5 d previously with leaf material of the common pink‐edged red taxon of Lantana camara. Both therapies were given by stomach tube as a single dose at 5 g/kg. Five of 6 calves in each of the groups given bentonite and activated charcoal recovered while 5 of 6 calves in the control group died. Calves given bentonite took 3 d longer on average to recover fully than those given activated charcoal but the effects of the 2 therapies on plasma total bilirubln concentrations were statistically indistinguishable. Bentonite was judged to have promise as a cheap alternative to activated charcoal for therapy of lantana poisoning of cattle.
Eye diseases in Siberian husky dogs
Authors: STANLEY RG , BLOGG JR
Published: March 2008

SUMMARY A full ophthalmic examination was performed on 40 Siberian husky dogs using direct and Indirect ophthalmoscopy, gonloscopy and nasolacrimal cannulation. Eight (20%) of the dogs were found to have distichia, 10 (25%) had excessive medial caruncular hairs, 8 (20%) had absence, displacement, or narrowing of the nasolacrimal puncta, 2 (5%) had bilateral corneal crystalline opacities, and 2 (5%) had unilateral areas of lateral corneal lipidosis. Fifty percent of the dogs had some abnormality of the Lridocorneal (drainage) angle. However, In only one of these was the deformity severe enough to require glaucoma prophylaxis. An association between blue lris colour and malformation of the lridocorneal angle was noted.
Evaluation of an immunofluorescence test on direct smears of conjunctival and urogenital swabs taken from koalas for the detection of Chlamydia psittaci
Authors: CANFIELD PJ , LOVE DN , MEARNS G. , FARRAM E.
Published: March 2008

SUMMARY The Chlamydia‐Cel Vet IF Test (CCVIT), a commercially available immunofluorescence test for use on direct smears of clinical specimens, was evaluated In a colony of 43 captive koalas. The test is based on a monoclonal antibody directed against the chlamydial common group specific lipopolysaccharide antigen. Swabs were taken from conjunctiva and penis or urogenital sinus and used for direct smear evaluation and cell culture isolation. Compared with isolation of the organism In cell culture, the CCVIT on direct smears of conjunctival swabs presented a sensitivity of 88%, a specificity of 100%, a positive predictive value (PV+) of 100% and a negative predictive value (PV‐) of 97%. The CCVIT on direct smears of urogenital swabs presented a sensitivity of 90%, a specificity of 84%, a PV+ of 86% and a PV‐ of 89%. The overall sensitivity was 89% (95% confidence Interval [Cl] of 71% to 97%), the specificity 94% (95% Cl of 84% to 98%), the PV+ 89% and the PV‐ 94%. It was concluded that the CCVIT on direct smears was suitable as a diagnostic screening test for the detection of Chlamydia psittaci in koalas.
Impact of dung from ivermectin‐treated sheep on oogenesis and survival of adult Lucilia cuprina
Authors: MAHON RJ , WARDHAUGH KG
Published: March 2008

SUMMARY Females of the Australian sheep blowfly, Lucilia cuprina, exploit sheep dung as a source of protein for egg development. Flies fed on dung collected from sheep 1 to 6 days after being drenched with the broad‐spectrum antiparasitic drug Ivermectin* showed delayed reproductive development and reduced fecundity. Male and female survival was also reduced. Despite these effects, except where the recommended frequency of drenching (1 to 4 times per annum) is greatly exceeded, it is unlikely that ivermectin residues will affect any useful reduction in blowfly populations.
A survey of farmers' attitudes to services provided by consulting veterinarians to the Western Australian sheep industry
Authors: CHAPMAN HM , COPLAND RS , SWAN RA , ROBERTSON ID
Published: March 2008

SUMMARY A postal survey was conducted of 80 sheep farmers in the Kojonup and Esperance districts of Western Australia to establish what they wanted from a veterinary service. Twenty five of the farmers surveyed used a sheep consultant, 25 did not, and 30 were interested in employing one. Farmers were asked questions about themselves and their attitudes to private veterinarians who provide specialist services to sheep farmers. Data reported here showed that farmers wanted a veterinarian who lived in the district, was well trained in sheep management and production, was enthusiastic and had good communication skills. The service provided should be whole‐farm and available to members of the consultant's group only. Regular newsletters and field days were necessary, but the provision of contract services, such as mulesing, lamb‐marking, drenching, pregnancy testing and sheep classing, and ‘fire‐brigade’ services for sick animals, were not rated as important. Most farmers were unwilling or unable to give a dollar value for the likely benefits of a consultancy service. Non‐financial benefits included keeping farmers up to date with new technical developments and information. The survey also showed that a veterinarian specialising in services to sheep farmers could be confident of employment.
Biological characterisation of Australian isolates of chicken anaemia agent
Authors: CONNOR TJ , McNEILLY F. , FIRTH GA , McNULTY MS
Published: March 2008

SUMMARY Three Australian Isolates of chicken anaemia agent (CAA) resisted treatment at 70°C for 5 min and chloroform treatment. Although minor antigenic differences were detected using monoclonal antibodies to CAA, the Australian isolates were indistinguishable from the reference Cux‐1 and Gifu‐1 isolates in cross‐immunofluorescence and cross‐neutralisation tests employing polyclonal chicken antiserums. The Australian viruses were pathogenic for intramuscularly inoculated 1‐day‐old SPF chicks, but were less pathogenic for 7‐day‐old chicks. Thus the Australian isolates of CAA did not differ significantly in these properties from previously characterised CAA isolates from other continents.
Use of phenytoin to treat horses with Australian stringhalt
Authors: HUNTINGTON PJ , SENEQUE S. , SLOCOMBE RF , JEFFCOTT LB , MCLEAN A. , LUFF AR
Published: March 2008

SUMMARYFive horses with Australian stringhalt were treated with 15 mg/kg phenytoin orally for 2 weeks. During the second week of the trial, 3 of the horses were given an additional dose of 10 mg/kg phenytoin. The response to treatment was clinically assessed by grading the severity of the gait abnormality at the walk, trot, turning and backing twice dally.

There was a significant (P<0.05) Improvement in the gait abnormality when pre‐treatment values were compared with the mean of the last 3 assessments before treatment stopped. When reassessed 2 weeks after treatment ceased, there remained a significant (P<0.05) Improvement compared with pre‐treatment values at the trot and on backing, but not at the walk or turning.

Surface electromyographic recordings were made weekly from the long digital extensor muscle, and there was a change to a near normal recording by the end of treatment. Plasma phenytoin concentrations were monitored during the trial, and the dose rates used achieved a steady state with a mean plasma level of 37+7 μmol/l. There was wide variability between plasma concentrations in different horses, although there was no difference in absorption between administration of the phenytoin as a paste, or when it was mixed in the feed. Although mild tranquillisation was seen after treatment, there were no clinical, haematological or biochemical signs of toxicity from the phenytoin therapy.
Diethylstilboestrol—clinical pharmacology and alternatives in small animal practice
Authors: PAGE SW
Published: March 2008

SUMMARY Diethylstilboestrol is currently only available in Australia for oral use in dogs and cats. As an orally and systemically active non‐steroidal oestrogen, DES has been widely used in small animal veterinary medicine for a variety of indications. A review of the literature reveals that many of the recommendations for use are founded on anecdotal or unreported clinical observations. While many of the uses may be valid, accurate determinations of optimum dosing regimens have not been defined. This is especially unfortunate in view of the potential toxicity of DES to small animals. Nevertheless, particularly in cases of low‐dose intermittent administration, oral DES appears indicated at least until data on alternative safe and effective interventions become available.
Factors affecting the natural transmission of bovine leukaemia virus infection in Queensland dairy herds
Authors: DIMMOCK CK , CHUNG YS , MACKENZIE AR
Published: March 2008

SUMMARY Natural transmission of bovine leukaemia virus (BLV) infection in south‐eastern Queensland dairy herds was slow in 2 herds with a low to moderate (13 to 22%) prevalence of infection. Infection spread much more rapidly in a herd that had a higher prevalence (42%) when first tested. In a 13 month study of this herd, the cumulative incidence of infection was 24%. In one herd new infections were confined almost entirely to calves of uninfected dams. Following the end of feeding bulk milk to calves, a common practice in dairy herds, no more calves in this herd became infected.

In laboratory experiments, neither prolonged housing of susceptible calves with infected cattle, consumption of drinking water contaminated with infected blood, nor inoculation of sheep with saliva from infected cattle resulted in transmission of BLV infection. Sheep were infected by subcutaneous inoculation of a suspension of purified lymphocytes from an infected heifer. The minimum infective dose was 103 lymphocytes, equivalent to the number of lymphocytes in approximately 0.1 μl blood. Thus, procedures involving the transfer of a very small volume of blood from animal‐to‐animal have the potential to transmit infection.
Photosensitisation and crystal‐associated cholangiohepatopathy in sheep grazing Brachiaria decumbens
Authors: GRAYDON RJ , HAMID H. , ZAHARI P. , GARDINER C.
Published: March 2008

SUMMARY Two outbreaks of photosensitivity and jaundice in sheep grazing the grass, Brachiaria decumbens, in West Java in 1983 and 1990 are described. Aggregates of acicular clefts and crystals were present in bile canaliculi, bile ducts, Kupffer cells, hepatocytes and in kidney tubules. The number of crystals increased with the length of exposure to the plant and sheep that died had the largest accumulations. These crystalline structures have not been reported before in this syndrome, but are similar to those seen in Tribulus terrestris and Panicum spp toxicities.
Comparison of the Johne's absorbed EIA and the complement‐fixation test for the diagnosis of Johne's disease in cattle
Authors: RIDGE SE , MORGAN IR , SOCKETT DC , COLLINS MT , CONDRON RJ , SKILBECK NW , WEBBER JJ
Published: March 2008

SUMMARYA commercially available absorbed ELISA for the diagnosis of Johne's disease (JD) (paratuberculosis) in cattle, the Johne's Absorbed EIA¶, was compared with the conventional complement‐fixation test (CFT) used in Australia. Stored plasma from 3 Victorian dairy herds with a history of JD, sera from specimens submitted from animals showing clinical signs of JD and sera from the US National Repository for Paratuberculosis Specimens were used to determine the sensitivity of each test. The EIA detected 48.8% of 43 Australian animals with subclinical JD, while the CFT detected only 12 (21.4%) of 56 subclinically affected cattle. Of 150 subclinically infected US cattle, the EIA detected 47.3% and the CFT detected 52.0%. The EIA detected 59.7% of animals which at the time of sampling were sheddingMycobacterium paratuberculosisin their faeces, but showed no clinical signs of JD, while the CFT detected 57.3%. The EIA correctly identified 88.2% of 136 histologically confirmed clinical cases, and the CFT detected 83.4%.

The specificity of each test was determined by testing sera collected at slaughter from animals residing in a known JD‐free area of Australia, and from samples from the US National Repository of Paratuberculosis Specimens collected from certified‐free herds in Wisconsin. The EIA was found to have a specificity of 99.8% when 998 Australian animals were used as the test population, and 99.0% when 196 US animals were used. The specificity of the CFT using Australian samples was 96.9% and 95.2% using American samples.
Racing performance of Thoroughbred horses after arthroscopic surgery of the carpus
Authors: KANNEGIETER NJ , RYAN N.
Published: March 2008

SUMMARY The case record, and subsequent racing performance, of 110 horses that had undergone arthroscopic surgery of the carpus, were reviewed. Of these, 87% resumed racing, with 43% able to win at least one race, after surgery. Horses with chip fractures from the distal radius had the best prognosis, while horses with sagittal fractures of the third carpal bone had the poorest. The performance of horses with bilateral lesions was similar to those with unilateral lesions. It was concluded that arthroscopic surgery was a suitable technique for the diagnosis and treatment of carpal lesions in the horse.
Serum immunoglobulin concentrations in genetically different types of suckling beef calves in a tropical environment
Authors: O'KELLY JC
Published: March 2008

SUMMARY Factors influencing the serum concentrations of γ‐globulin (γ‐G) during the neonatal period were studied in Shorthorn x Hereford (SH), Africander x SH and Brahman x SH calves born to cows grazing in a tropical environment. There were no significant effects of age of dam, sex or breed of calf on the γ‐G concentrations of calves from birth to 48 hours of age. Concentrations of γ‐G fell within two ranges: group A, 10 to 20 g/l and group B, 35 to 70 g/l. The number of calves in each group was not significantly different between breeds and overall 30% of calves were in group A. Body weight gain from birth to 10‐day‐old was greater (P <0.01) in calves in group B than in group A. Plasma cholesterol concentrations in 10‐day‐old calves were higher in group B than in group A calves supporting the interpretation that group B calves had higher milk intakes. Identification of calves receiving adequate amounts of colostrum has fundamental significance for the efficient production of cattle in the tropics.
Detection of reserpine in horses by high‐performance liquid chromatography
Authors: CHAPMAN CB , COURAGE P. , HUNTINGTON PJ
Published: March 2008

SUMMARY A high‐performance liquid chromatography (HPLC) assay was developed for the detection of reserpine. The assay was used to monitor the plasma concentrations of the drug given intramuscularly on one or two occasions to five horses. The blood concentrations of reserpine varied quite considerably between horses given the same dose of the drug. However, on average, reserpine could be detected consistently, and quantified, for 48 h after a single dose of 2.5 mg, and for a similar period after the second of two 2.5 mg doses given 13 d apart. Because of the apparently large variability in the pharmacokinetics of reserpine in horses, exact times cannot be given beyond which the drug will no longer be detectable in the plasma. However, following two doses of 2.5 mg reserpine given 13 d apart, at least 7 d must elapse after the second dose before there is no drug detectable in the plasma of most horses.
The influence of maternal antibody and age of calves on effective vaccination against Leptospira interrogans serovar hardjo
Authors: PALIT A. , MIDDLETON H. , SHEERS J. , BASILONE C.
Published: March 2008

SUMMARY Twelve seronegative rows were vaccinated with an experimental bivalent Leptospira interrogans serovars hardjo and pomona vaccine late in their first pregnancy.

Calves born of these dams were divided into 4 equal groups that received this vaccine at 4,6,10 and 18 weeks of age, respectively. Before vaccination the group geometric mean titres of maternally‐derived circulating antibodies ranged from 2 to 25 for the microscopic agglutination (MA) test and 3 to 35 for enzyme‐linked immunosorbent assay (ELISA) using a serovar hardjo outer envelope antigen. Post‐vaccination peak titres were 645 to 1612 for MA and 562 to 1037 for ELISA, respectively. Calves vaccinated at the youngest age, had the highest pre‐vaccination circulating maternal antibody titres, but showed the smallest rise in post‐vaccination antibody titres. Circulating maternal antibody was detected in calves up to 13 weeks of age.

All immunised calves were protected against a virulent challenge with serovar hardjo type Hardjobovis, regardless of their age or maternally‐derived antibody titres. These findings indicate that calves as young as 4 weeks old, vaccinated in the presence of maternally‐derived antibody, can be fully protected against homologous virulent challenge.
Analysis of post‐partum fertility in mares on a Thoroughbred stud in southern Victoria
Authors: LOWIS TC , HYLAND JH
Published: March 2008

SUMMARY This project surveys the reproductive performance of 154 foaling Thoroughbred mares on a commercial stud in southern Victoria. Of these, 96 were served on foal heat (FHS) and 58 were served at a subsequent prostaglandin‐induced oestrus (PGS). The PGS group of mares performed more favourably in all aspects except the foaling‐to‐conception interval where there was a 9.4 day advantage to the FHS group. The first service conception rate in the FHS group was 47.9% compared with 55.2% in PGS mares. Second heat period conception rates were 46% vs 57.7% for FHS and PGS mares, respectively. Overall conception rates at the end of the breeding season were 83.3% in the FHS group and 89.7% in the PGS group. Pregnancy losses before day 45 and after day 45 were 10% and 9.3% in FHS mares and 3.9% and 3.6% in the PGS mares. Served oestrous periods per conception numbered 1.7 and 1.4 in the FHS and PGS groups, respectively.
Chloramphenicol 1. Hazards of use and the current regulatory environment
Authors: PAGE SW
Published: March 2008

Chloramphenicol is a broad‐spectrum antibiotic which has enjoyed extensive use in both medical and veterinary practice. Shortly after its introduction in the late 1940s, the use of chloramphenicol was associated with the induction of an idiosyncratic form of aplastic anaemia in man. This rare and unpredictable adverse effect has since been associated not only with systemic use but with topical applications, as well as occupational exposure. Recognition of the small risk of a potentially fatal adverse reaction, together with the risk of selection of chloramphenicol‐resistant pathogens, has led to restrictions on the veterinary uses of chloramphenicol. In Australia at present, the use of chloramphenicol is only permitted in small animals. Its use is specifically prohibited in food‐producing animals, including horses.
Chloramphenicol 3. Clinical pharmacology of systemic use in the horse
Authors: PAGE SW
Published: March 2008

The use of chloramphenicol in the horse is now prohibited as horses are classified as food‐producing animals. However, chloramphenicol has until recently been widely available for oral, intramuscular or intravenous administration. A critical appraisal of the published literature on the use of chloramphenicol in the horse clearly demonstrates that there are sound pharmacokinetic and microbiological reasons for concluding that chloramphenicol is not an appropriate antibiotic for systemic use. The short half‐life of chloramphenicol in the horse, together with the broad range of minimum inhibitory concentrations of target pathogens, preclude the use of practical dosage regimens. It can be concluded that the withdrawal of chloramphenicol will have no adverse effects on chemotherapy in the horse.
Heliotropium europaeum poisoning of sheep with low liver copper concentrations and the preventive efficacy of cobalt and antimethanogen
Authors: PETERSON JE , PAYNE AL , CULVENOR CCJ
Published: March 2008

In a field experiment in the Mallee district of Victoria, Merino x Border Leicester ewes and wethers grazed Hellotroplum europaeum (hellotrope) over periods of 3 to 4 months in 4 successive years. By the end of the second year 12% (14 of 120) of the sheep had died; after 4 years the loss attributable to hellotrope was between 18% and 35%. Mortality was not affected by intraruminal treatment with cobalt or antimethanogen. At the end of the experiment the highest concentration of copper in the liver was 1.95 mmol/kg wet weight (approximately 413 mUg/g dry weight). The relatively low mortality from primary hellotrope poisoning and the low concentration of copper in the liver of sheep grazing the plant are discussed in relation to the contrasting situation that prevails in the Riverina area of New South Wales. The importance of local environmental factors in the management of hellotrope grazing by sheep is emphasised, particularly in relation to the number of seasons in which the plant may be a major component of the diet.
The distribution and prevalence of Theileria buffeli in cattle in Queensland
Authors: STEWART NP , STANDFAST NF , BALDOCK FC , REID DJ , de VOS AJ
Published: March 2008

The distribution and prevalence of Theileria buffeli in Queensland cattle were investigated using serum samples and blood films collected primarily for brucellosis surveillance and tick fever diagnosis. Serums from 8654 cattle from 357 farms throughout Queensland were examined by an indirect fluorescent antibody test for antibody to T buffeli. In addition, 347 peripheral blood films collected from 147 farms in south‐eastern Queensland were examined for plroplasms of T buffeli.

The overall herd and animal prevalences for T buffeli were 75% and 41%, respectively. There was significant variation among regions in both herd and animal prevalences (P <0.001). Herd and animal prevalences were highest in the north and east decreasing westward. The results indicate that T buffeli is more widespread in Queensland than previously thought.
BOOK REVIEWS
Authors: Wright Dick
Published: March 2008

Book reviewed in this article:

Large Animal Neurology, A Handbook for Veterinary Clinicians, I G Mayhew
Efficacy and safety of ivermectin applied topically to cattle under field conditions in Australia
Authors: EAGLESON JS , ALLERTON OR
Published: March 2008

Fifteen controlled field trials were conducted to evaluate the efficacy against gastrointestinal nematodes and safety of ivermectin when applied topically to cattle in Australia. Three hundred and fifty‐one cattle received ivermectin, and 88 were untreated controls. The trials were conducted in 3 States and included a variety of cattle breeds and environmental conditions. Faecal samples were collected before treatment and 11 to 14 days after treatment for nematode egg counts. Data from these trials show that under Australian conditions, ivermectin applied along the mid line of the back from the withers to the sacral region at a dose rate of 500 mcg/kg body weight, effectively controlled gastrointestinal nematode infections, and did not produce unacceptable adverse reactions in the animals.
BOOK REVIEW
Authors: Jonsson NN
Published: March 2008

Digestive Diseases in the Dog and Cat, James W Simpson and Roderick
Salivary and plasma cortisol as an index of stress in goats
Authors: GREENWOOD PL , SHUTT DA
Published: March 2008

Total assayable cortisol in plasma was highly correlated (r = 0.97) with physiologically active free cortisol in plasma after routine management procedures in 1‐ to 3‐weeks‐old goats. Transport of adult goats caused significant increases (P < 0.001) in free cortisol in saliva and in free and total cortisol in plasma. No difference (P >0.05) between concentrations of free cortisol in saliva and in plasma was apparent before or after transport. The results demonstrated that the salivary cortisol method is a useful measure of stress in adult goats, and that the relationship between free and total cortisol in plasma, and the adrenocortical response to transport, appear to be similar in sheep and goats.
Mechanisms underlying Phalaris aquatica “sudden death” syndrome in sheep
Authors: BOURKE CA , CARRIGAN MJ
Published: March 2008

Twenty outbreaks of Phalaris aquatica “sudden death” syndrome in sheep were Investigated between 1981 and 1991. Four were confirmed and one was suspected, to be a cardiac disorder; 5 were confirmed and 3 were suspected, to be a polio‐encephalomalacic disorder; the aetiology of the remaining 7 outbreaks could not be determined. Potentially toxic levels of hydrocyanic acid (20 to 36 mg/100 g) were measured in the 3 toxic phalaris pastures tested. The measurement of potentially toxic levels of nitrate nitrogen (2920 μg/g) in toxic phalaris pastures by others, was noted. It is suggested that phalaris “sudden death” syndrome could have as many as 4 different underlying mechanisms, and that these might reflect the presence in the plant of a cardio‐respiratory toxin, a thiaminase and amine co‐substate, cyanogenic compounds, and nitrate compounds.
Aspergillosis in camels affected with a specific respiratory and enteric syndrome
Authors: EL‐KHOULY A‐BA , GADIR FA , CLUER DD , MANEFIELD GW
Published: March 2008

During the summer of 1990 deaths, occurred in racing camels (Camelus dromedarius) associated with a specific disease syndrome. Clinical signs included pyrexia, coughing, lachrymation, oedema of the throat and submandibular region and enlargement of submandibular lymph nodes. In terminal cases nervous signs were present and sometimes there was bloody diarrhoea and vomiting. Of 480 camels at least 70 animals were affected with the disease and about 40 died. Morbidity and mortality was greater in camels recently imported.

Consistent necropsy findings were extensive petechial and ecchymotic haemorrhage beneath the epicardium, endocardium and visceral pleura and in the mediastinal lymph nodes, and haemorrhagic oedema of the pharyngeal and laryngeal areas. Haemorrhages occurred more variably in abdominal organs and on the omasal and abomasal mucosa. Bronchopneumonia, omasitis and abomasitis were observed on microscopic examination, together with liver and kidney lesions of presumed toxic origin.

Fungal hyphae and, occasionally, the characteristic conidial morphology of Aspergillus fumigatus were seen in sections and direct smears from lesions in the respiratory and alimentary tracts. A fumigatus was cultured from trachea, bronchi, bronchioles, lung tissue, heart blood, omasum, abomasum, ileum and submandibular lymph nodes. Whether the role of Aspergillus in the overall syndrome is primary or secondary has not been established; no other potential aetiological agent has been identified.
Ovine nasal zygomycosis caused by Conidiobolus incongruus
Authors: CARRIGAN MJ , SMALL AC , PERRY GH
Published: March 2008

SUMMARY: About 700 sheep died on 52 farms in north‐western New South Wales and south‐western Queensland over a 3 mo period. Affected animals had a marked asymmetrical swelling of the face, extending from the nostril to just anterior to the eyes. They lost condition rapidly and died within 7 to 10 days. At necropsy there was a unilateral severe necrogranulomatous rhinitis with extension of inflammation into the adjacent subcutaneous tissue, nasal septum and hard palate. Metastatic lesions were present in the draining lymph nodes and in the thorax. Histological changes consisted of a granulomatous reaction with numerous eosinophilic focl of necrosis and a diffuse, heavy, mixed inflammatory cell response. Many vessels had segmental necrosis and thrombosis. Fungal hyphae were numerous, particularly within or associated with necrotic foci. Conidiobolus incongruus was isolated from nasal tissues, parotid and submandibular lymph nodes and pulmonary lesions.
Improved feed intake and body weight change in sheep treated with dexamethasone at entry into pens or feedlots
Authors: ADAMS NR , SANDERS MR
Published: March 2008

Treatment with the synthetic glucocorticoid dexamethasone sodium phosphate increased the feed intake of sheep within 24 h. A single treatment with the longer‐acting compound dexamethasone trimethylacetate had a slower effect, but resulted in improved feed intake and enhanced body weight gain over a period of 7 to 14 days. Treatment was effective in sheep housed individually and in sheep penned in groups. The improvement in body weight gain disappeared 15 to 20 days after a single treatment, but in most studies treated sheep had less variability in weight change than untreated sheep at this time. A statistically significant increase in body weight gain was observed in 8 of 11 trials; in the other 3 trials, it appeared that the feed intake of the untreated sheep was already maximal. Wethers treated with dexamethasone trimethylacetate on arrival at an assembly point for live export arrived in the Middle East 23 days later with a lower mean weight loss, partly because fewer sheep lost a significant amount of weight.