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Failure of passive immunity transfer (FPIT) increases the risk of morbidity and mortality in dairy calves. The prevalence of FPIT in dairy calves has generally been reported to be high, with FPIT estimated to occur in 38%-42% of Australian dairy calves. However, the focus of previous studies has been on replacement heifer calves. Our aim was to assess the prevalence of FPIT in Victorian bobby calves (non-replacement dairy calves). We collected blood samples from 3608 bobby calves at three abattoirs at exsanguination, and measured serum total protein as an indicator of passive transfer. We found that 36% of bobby calves showed evidence of FPIT (serum total protein ≤52 g/L), and 50% of calves had poor or fair passive transfer (<58 g/L). When a subset of calves (from farms with more than five calves in the dataset) was analysed using a linear mixed model, Jersey calves and crossbred/other calves had an estimated 5.3 g/L and 5.1 g/L higher serum total protein concentration, respectively, than Holstein-Friesian calves (P < 0.001). Our results suggest that the prevalence of FPIT in bobby calves at abattoirs is similar to that reported in dairy heifer calves sampled on farms. A high prevalence of FPIT has implications for bobby calf morbidity and mortality, as well as calf viability and profitability for dairy-beef production., (© 2022 The Authors. Australian Veterinary Journal published by John Wiley & Sons Australia, Ltd on behalf of Australian Veterinary Association.)

Background: Comprehensive hematology and biochemistry RIs are currently lacking in the literature for young dairy calves based on sample sizes more than 120. Young dairy calves are at a relatively high risk of poor health and welfare outcomes. They have a high risk of morbidity and mortality in the first 2 weeks of life, and many are transported and fasted during this time. For example, non-replacement calves in Australia and New Zealand are usually 5-12 days old when transported to abattoirs, meaning that calves of this age group are potentially at risk of both health and welfare compromise. Given these factors, sound, comprehensive, age-specific biochemical and hematologic RIs are needed for both veterinary clinical practice and to inform research on calf health and welfare., Objectives: The aim of this study was to generate age-specific hematology and biochemistry RIs for dairy calves aged 5-12 days., Methods: We collected blood samples from 141 fasted, healthy dairy calves on 10 Australian farms. Reference Value Advisor software was used to calculate nonparametric RIs for multiple biochemistry and hematology variables., Results: RIs for a panel of hematology and biochemistry variables in dairy calves aged 5-12 days old were derived., Conclusions: These RIs will be useful for clinical veterinary practice, as well as for research on dairy calf health and welfare., (© 2021 American Society for Veterinary Clinical Pathology.)

Background: There is little information on foal mortality and the epidemiology of diseases in the neonatal period in Australian equine breeding enterprises., Methodology: This was a prospective cohort study of 1219 foals on 15 breeding farms in south-eastern Australia to identify the proportion of foals recognised on farm as abnormal at birth or within the first 48 h postpartum, determine the prevalence and risk factors for neonatal disease and assess the subsequent performance of foals in the study population., Results: Overall, 27 foals died within 6 weeks of birth in the study population (2.2%), 142 foals (11.6%) were reported as abnormal at birth, and 304 (25.3%) were regarded as abnormal in the first 48 h postpartum. Non-septic orthopaedic disease (NSOD) was the most common abnormality recognised. Premature foals and foals born after dystocia or abnormal parturition were more likely to have clinical abnormalities recognised, but the intensity of nursing care did not predict outcome. Prophylactic administration of antimicrobial drugs was associated with increased mortality and septic disease. Maternal periparturient problems, foal gender, abnormality at birth and the presence of septic disease or neonatal maladjustment were associated with decreased performance outcomes, whereas measures to assess and augment passive immune transfer were associated with improved athletic performance., Conclusions and Relevance: Information in the current study is important for the treatment and management decisions on farm and to identify industry welfare and production priorities. Although the incidence of all outcome variables was variable, factors recognised on farm in the peri-parturient period were predictive of subsequent athletic performance., (© 2021 Australian Veterinary Association.)

Calf preweaning morbidity and mortality risks have been reported as high in several countries, with average values approximating 35 and 7%, respectively. However, limited data are available for calf morbidity and mortality risks on Australian dairy farms. The aims of this study were (1) to investigate current calf management practices on dairy farms in Australia and their association with herd-level morbidity and mortality using a questionnaire-based, cross-sectional study; and (2) to estimate the prevalence of common enteropathogens causing diarrhea, the failure of passive transfer of immunity, and poor colostrum quality in a sample of Australian dairy farms. We analyzed 106 completed questionnaires and samples from 23 farms (202 fecal, 253 calf serum, and 221 colostrum samples). Morbidity and mortality risks reported by farmers in preweaned heifers were 23.8 and 5.6%, respectively. These risks were above the Australian dairy industry targets in 75.5 and 66.7% of respondents. The zoonotic pathogens Cryptosporidium spp. and Salmonella spp. were the most prevalent enteropathogens, with a true prevalence of 40.9 and 25.2%, respectively. Salmonella O-group D was present in 67.9% of Salmonella-positive samples, followed by O-groups B (17.9%) and C (10.7%). Failure of transfer of passive immunity (IgG <10 g/L) was observed in 41.9% of calves (mean herd-level prevalence of 36.2%), and only 19.5% of colostrum samples met the standards for immunoglobulin content and microbiological quality. Collectively, these data indicate that there is still considerable room for improvement in calf-rearing practices on Australian dairy farms, particularly with regard to colostrum management and feeding hygiene., (Copyright © 2019 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Diarrhoeal disease (scours) in piglets, often associated with enterotoxigenic Escherichia coli (ETEC), is a substantial financial burden to the pig industry worldwide. Previous research has not explicitly examined the relationships between farm, pen and microbiological factors. Here we present a state of the art analysis to reveal empirical indirect - as well as direct - associations between management factors as putative risks for scours in pre- and post-weaned piglets. A Bayesian Network is constructed to identify the optimal structural model describing the relationships between risk factors. An additive model is then built to estimate more epidemiologically familiar odds ratios. Farm-level variance dominates the model, making many pen-level associations null. However, there is evidence that pre-weaning scours are less likely on farms with <400 sows (0.14, 0.03-0.50). Our results strongly suggest that smaller production units (piglets/pen) could reduce the incidence of scours in piglets. There is also some evidence that ownership of other livestock is a potential risk factor for pre-weaning scours, although this was observed only at one farm. Future research should be directed at better understanding the role of herd size and investigating the relationship between managing other livestock and the occurrence of scours in pig herds.

Diarrhoeal diseases in piglets caused by Escherichia coli are responsible for substantial losses each year in the Australian pig industry. A cross-sectional survey was conducted (September 2013-May 2014) across 22 commercial pig herds located in southeastern Australia: NSW (n = 9); VIC (n = 10); and SA (n = 3), to estimate the prevalence of E. coli associated diarrhoea in pre- and post-weaned piglets and to identify key risk factors associated with E. coli disease. A questionnaire on management and husbandry practices was included. Faecal samples (n = 50 from each herd) were tested for the presence of β-haemolytic E. coli. Species level identification was confirmed by matrix-assisted laser desorption / ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). ETEC virulence and enterotoxin genes (F4, F5, F6, F18, F41, STa, STb and LT) were screened for by multiplex PCR. This study assessed 60 potential risk factors for E. coli disease in post-weaned piglets, with 2 key factors-recent disease events and the presence of bedding, statistically associated with the presence of post-weaning scours. The prevalence of diarrhea in pre-weaned pens was 17% (16/93), compared with 24% (24/102) in post-weaned pens. The most prevalent β-haemolytic ETEC genes were F18 (32%) and STb (32%) but isolates were more likely to contain F4:STb (11 of 22 herds, 23%), than F18:STb (5 of 22 herds, 6%). These findings indicate that recent disease events that have occurred within the last 12 months, and by the use of bedding or not maintaining fresh bedding can have significant impacts on piglet diarrhoea.

Objective: To determine the clinical safety and efficacy of alfaxalone in bitches undergoing caesarean section (CS) and their puppies when it is administered for induction of anaesthesia followed by maintenance with isoflurane and oxygen and in conjunction with perioperative pharmaceuticals., Design: A multicentre, randomised, positive-controlled clinical study., Methods: A total of 74 bitches were enrolled in the study with 48/74 (65%) and 26/74 (35%) receiving alfaxalone and propofol, respectively, for induction of anaesthesia. Bitches were examined prior to induction and monitored during induction, surgery and recovery. Assessments were made for quality of induction, maintenance and recovery from anaesthesia. Assessments were made on pup viability for suction, dorsal flexion, withdrawal and anogenital reflexes., Results: Of the 48 bitches receiving alfaxalone, 47 (98%) and 39 (81%) scored a top score of excellent for induction and anaesthesia effectiveness, respectively. For the same parameters with propofol in 26 bitches, 23 (88%) and 17 (65%) scored excellent. Average scores for recovery were not different between the two treatment groups with alfaxalone 46/48 (96%) and 25/26 (96%) of propofol induced bitches scoring a good or excellent rating. Bitches tolerated a number of concurrent medications throughout the peri-operative period. No bitch fatalities were observed in this study. There were no statistically significant differences between treatment groups for the puppy variables. Live puppies born by CS to bitches having been administered alfaxalone or propofol had similar survival rates 24 h after birth (i.e. 205/213 (96%) and 124/131 (95%), respectively)., Conclusion: This study confirms the safety and efficacy of alfaxalone for the purpose of anaesthetic induction for CS in the bitch. In addition, alfaxalone had a negligible effect on the neonate with >95% of puppies alive 24 h after the bitch had recovered from anaesthesia with alfaxalone induction., (© 2014 Australian Veterinary Association.)

Objective: Compare real-time reverse transcription polymerase chain reaction (qRT-PCR), a commercially available enzyme-linked immunosorbent assay (ELISA) and lateral flow immunochromatography assay (LAT) for the detection of rotavirus and coronavirus in faecal samples collected from diarrhoeic calves., Design: Prospective survey., Method: Samples were tested at two separate facilities using a commercial ELISA and an in-house qRT-PCR. Simple logistic regression was performed to examine the relationship between the two tests. A subset of samples was screened using qRT-PCR, ELISA and a commercial LAT dipstick (132 faecal samples were tested for coronavirus and 122 samples for rotavirus)., Results: Of the 586 samples tested, 131 (22.39%) and 468 (79.86%) were positive for coronavirus and group A rotavirus, respectively, using qRT-PCR. The number of samples positive on ELISA for coronavirus and rotavirus was 73 (12.46%) and 225 (38.40%), respectively. Using LAT, 30 (22.73%) and 43 (35.35%) samples were positive for coronavirus and rotavirus, respectively. Simple linear regression revealed a statistically significant (P < 0.05) but weak (r(2) =-0.07 and -0.40) correlation between the rotavirus/coronavirus qRT-PCR and ELISA, respectively. There was also poor agreement between the LAT and qRT-PCR assays., Conclusion: The sensitivity and specificity of the commercial ELISA and LAT assays evaluated in this study were low compared with qRT-PCR. The low positive and negative predictive values of the assays suggests that they were of limited diagnostic benefit in the population sampled., (© 2012 The Authors. Australian Veterinary Journal © 2012 Australian Veterinary Association.)

Objective: To determine the effect of applying plastic clips to the breech and tail of lambs on the perineal and tail bare areas, breech wrinkle, dag (faecal) accumulation, urine stain, body weight and survival of lambs, compared with unclipped, unmulesed lambs and mulesed lambs., Method: The study was conducted on five commercial wool-growing farms in southern Australia. On each study site lambs (2-12-weeks-old) were divided into three groups: (1) unclipped, unmulesed control (tail dock only); (2) treated with clips; and (3) treated with the mules operation. Evaluations of effects, including visual scoring, bare area measurements and body weight, were performed before treatment and on or approximately days 30, 60, 90 and 180 after treatment. On each occasion, lambs were recorded as either present or absent to allow estimates of survival., Results: The clip treatment increased the size of the perineal and tail bare areas compared with the unclipped, unmulesed control lambs (P < 0.05), although the increases were less than in mulesed lambs (P < 0.05). The clips reduced breech wrinkle, dag and urine stain to levels partway between those recorded in the unclipped, unmulesed controls and the mulesed lambs (P < 0.05). Clipped lambs weighed more than mulesed lambs after treatment (days 30-90 P < 0.001; day 180 P < 0.01) and had higher cumulative percentage survival to 90 days after treatment (P = 0.03)., Conclusions: The clips successfully modified the breech region of lambs, although the changes were less than with mulesing. The clips did not reduce the body weight of lambs, compared with the unclipped, unmulesed control lambs, and improved 90-day cumulative percentage survival compared with mulesed lambs., (© 2012 The Authors. Australian Veterinary Journal © 2012 Australian Veterinary Association.)

Objective: To investigate the effects of live weight, sex and other factors on deciduous (first incisor) loss and permanent first incisor development in Angora goats., Design: Goats were part of a pen study on the effects of energy intake in Angora does during pregnancy and lactation on kid growth and development. The design was three levels of nutrition in mid-pregnancy × two levels of postnatal nutrition in 17 randomised blocks., Methods: Conception times were calculated by using artificial insemination, with ultrasound examination 43 days after insemination. Does were fed different amounts of a formulated diet in their pens. After weaning, goats were grazed in sex groups. Deciduous first incisor loss and permanent first incisor development were recorded at 11 time points from 14 to 20 months of age., Results: For each sex, the time for visible eruption and full development of permanent first incisor declined linearly with increased live weight by 5.9 and 5.4 days/kg live weight, respectively. The time to reach similar development stages for first permanent incisors eruption was 3 months longer for the lightest animals compared with the heaviest animals. Date of birth, birth weight, doe age, growth rates, mid-pregnancy and postnatal nutrition, parity, day of weaning and weaning weight had no detectable effect., Conclusions: The results explain much of the substantial range in reported first permanent incisor eruption dates for small ruminants and have application in ageing of goats, marketing of kids for meat, in the selection of animals for breeding flocks and in educational material., (© 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.)

This paper, the last in a series of reviews of neurological diseases of ruminants in Australia, discusses a range of neurogenetic disorders of cattle, sheep and goats, including necrotising encephalomyelopathy, glycogen storage disorders, cerebellar abiotrophy and β-mannosidosis. They are categorised by the species and breeds in which they occur., (© 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.)

OBJECTIVE To identify the common serotypes and antimicrobial resistance patterns of Salmonella spp. associated with diarrhoea in Australian dairy calves under the age of 6 weeks. DESIGN Cross-sectional study. METHODS Faecal samples were collected from outbreaks of diarrhoea in dairy and dairy beef calves less than 6 weeks old. Samples were screened for Salmonella using standard enrichment culture techniques. The antimicrobial susceptibility to 12 commonly used veterinary and human antimicrobials was assessed using the Kirby-Bauer disk diffusion method and the susceptibility profiles of dairy and dairy beef properties were compared using Fisher's exact test. RESULTS Salmonella ser. Dublin, S. ser. Typhimurium and S. ser. Bovismorbificans were the three most common salmonella serotypes isolated. The majority of properties had one serotype. Most of the Salmonella isolates were not resistant to any of the antimicrobials tested. No resistance was seen to amikacin and nalidixic acid, and only one isolate was resistant to ceftiofur or amoxicillin-clavulanic acid. The most common antimicrobial resistance was to streptomycin, ampicillin or combination sulfonamides. Multi-drug resistance was detected in S. ser. Anatum, S. ser. Bovismorbificans, S. ser. Muenster, S. ser. Newport and S. ser. Typhimurium. Isolates from dairy beef properties were more likely to be resistant to ampicillin, kanamycin, neomycin, sulfamethoxazole/trimethoprim and tetracycline (P < 0.05) and were more likely to exhibit multi-drug resistance. CONCLUSION The prevalence of antimicrobial resistance in Salmonella isolates from dairy calves in Australia is low compared with that reported overseas. From a human health perspective, resistance to antimicrobials used in the treatment of human salmonellosis was infrequent., (© 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.)

The results of an accelerated immunisation schedule for horses used as part of the emergency response plan to contain and eradicate equine influenza in Australia in 2007 is described. The horses studied were vaccinated with a recombinant canarypox-vectored vaccine (ProteqFlu®, Merial) with a shorter interdose interval. Vaccinated horses included foals aged less than 4 months., (© 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.)

Analysis of pathology results from the 2007 equine influenza (EI) outbreak in Australia indicate that young foals in naïve horse populations are prone to developing broncho-interstitial pneumonia, and that this can be a rare manifestation of EI virus infection in mature horses. All horses may develop secondary bacterial bronchopneumonia, with mature horses more likely to die. EI outbreaks among heavily pregnant mares can result in increased neonatal losses because of premature placental separation and dystocia causing fetal hypoxia., (© 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.)

The hormonal factors that influence development from birth to weaning in otariid seals is still largely unknown. In the present study, a suite of thyroid hormones and cortisol were measured in Australian fur seal pups in order to determine baseline concentrations as well as to describe their endocrinology over this critical developmental period. A cross-section of newborn pups from a breeding colony located on Kanowna Island, Australia were sampled at six different times over the course of the 10 month lactation period. Sample times were designed to correspond to periods of heightened physiological change during pre-weaning development: post-natal, pre-molt, the initiation of molt, mid-molt, period of peak milk intake and weaning. Results indicate that the greatest hormonal changes were associated with the post-natal stage and molt, with molt showing the greatest changes, as has been reported for several species of pinnipeds. Two forms of thyroid hormones analyzed (Total T(4), and Free T(3)), increased with the initiation of the molt, and Free T(3) exhibited a second increase that was associated with the period of peak milk intake. The T(3):T(4) ratio was significantly lower during the initiation of molt than either pre- or mid-molt. The study was able to describe physiological change during the first year of life in Australian fur seals as well as document basal concentrations of thyroid hormones and cortisol in pups of this species., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: Determine the prevalence of the major enteric pathogens in dairy and dairy beef calves with diarrhoea in Australia., Design: Cross-sectional study., Methods: Faecal samples from 84 Australian dairy and dairy beef properties (597 samples) were screened for rotavirus and coronavirus using real-time reverse transcription polymerase chain reaction, for Salmonella spp. using selective enrichment faecal culture, and for enterotoxigenic Escherichia coli (K99) and Cryptosporidium parvum using a commercial enzyme-linked immunosorbent assay. A logistic regression with random effects model was used to compare prevalence of pathogens in dairy and dairy beef operations., Results: Enteric pathogens were isolated from 97.6% of outbreaks and 95.0% of samples. Rotavirus was the most common pathogen identified (477/597, 79.9%) followed by C. parvum (349/597, 58.5%), Salmonella spp. (142/597, 23.8%), coronavirus (129/597, 21.6%) and E. coli K99 (104/597, 17.4%). Multiple pathogens were identified on 96.4% of farms and from 71.0% of samples. Samples from dairy beef properties were more likely to have multiple pathogens than dairy properties (P < 0.05), whereas rotavirus and Salmonella spp. were more likely to be identified in samples collected from dairy beef than dairy properties (P < 0.05)., Conclusion: Most outbreaks of calf diarrhoea in dairy and dairy beef operations involve multiple pathogens. Rotavirus and C. parvum were the most frequently identified pathogens across production systems. Salmonella spp. and rotavirus were more frequently identified in dairy beef operations., (© 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.)

To provide objective data on the potential role of dingoes (Canis lupus dingo) in the life cycle of Neospora caninum in Australia, the production of N. caninum oocysts by experimentally infected canids was investigated. Three dingo pups raised in captivity and three domestic dogs were fed tissue from calves infected with an Australian isolate of N. caninum, Nc-Nowra. Oocysts of N. caninum, confirmed by species-specific PCR, were shed in low numbers by one dingo pup at 12-14 days p.i. The remaining animals did not shed oocysts. Furthermore, the blood from two out of three dingoes tested positive for DNA of N. caninum using PCR tests at 14 and 28 days p.i. Oocyst shedding from the intestinal tract of a dingo demonstrates that dingoes are definitive hosts of N. caninum and horizontal transmission of N. caninum from dingoes to farm animals and wildlife may occur in Australia., (2010 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.)

Objective: The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses., Procedures: A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods., Results: In the paddocks used (0.8-16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size., Conclusions: Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.

A 10-week-old female Ocicat was presented at a primary care feline veterinary practice for failure to thrive and diarrhoea. Numerous trophozoites, atypical for Giardia sp., were detected on a direct faecal examination, in addition to Giardia cysts. Although the failure to thrive and diarrhoea resolved following treatment for giardiasis, further diagnostic tests performed on faecal specimens from the kitten and 15 other Ocicats from the same cattery, including culture of trophozoites in In Pouch medium, PCR testing and molecular sequencing of PCR amplicons, confirmed infection with Tritrichomonas cf. foetus. This is the first report in Australia of feline trichomoniasis, which appears to be an emerging infectious disease of cats. Pertinent information regarding the clinical features, diagnosis, therapy, and potential source of feline trichomoniasis within Australia are discussed.

The land-based livestock industries in Australia face particular challenges in assuring high animal welfare standards due to large land areas and stock numbers, climatic extremes and relatively low inputs in terms of manpower and infrastructure. These factors make a major contribution to welfare issues associated with nutrition, health, mustering and handling, and transportation. In addition, welfare is seriously compromised by the invasive procedures that are conducted on livestock, such as castration, dehorning, mulesing and tail-docking. At least partial solutions to welfare issues associated with nutrition, health, mustering and handling are available now and should be universally adopted. There are potential solutions available for castration and dehorning, which require some further research and development. Genetic technologies can also provide a solution for dehorning, mulesing and tail-docking. Inevitably, all livestock experience transportation, and research and development is required to determine optimal practices for Australian conditions in order to minimise the negative impacts on animal welfare.

The ecology of virulent strains of Rhodococcus equi on horse farms is likely to influence the prevalence and severity of R. equi pneumonia in foals. This study examined the association between the ecology of virulent R. equi and the epidemiology of R. equi pneumonia by collecting air and soil samples over two breeding seasons (28 farm-year combinations) on Thoroughbred breeding farms with different reported prevalences of R. equi pneumonia. Colony blotting and DNA hybridization were used to detect and measure concentrations of virulent R. equi. The prevalence of R. equi pneumonia was associated with the airborne burden of virulent R. equi (both the concentration and the proportion of R. equi bacteria that were virulent) but was not associated with the burden of virulent R. equi in the soil. Univariable screening and multivariable model building were used to evaluate the effect of environmental and management factors on virulent R. equi burdens. Lower soil moisture concentrations and lower pasture heights were significantly associated with elevated airborne concentrations of virulent R. equi, as were the holding pens and lanes, which typically were sandy, dry, and devoid of pasture cover. Few variables appeared to influence concentrations of virulent R. equi in soil. Acidic soil conditions may have contributed to an elevated proportion of virulent strains within the R. equi population. Environmental management strategies that aim to reduce the level of exposure of susceptible foals to airborne virulent R. equi are most likely to reduce the impact of R. equi pneumonia on endemically affected farms.

A field trial was undertaken from 1999 until 2004 to determine the efficacy of a killed M. a. paratuberculosis vaccine, Gudair, for the control of ovine Johne's disease (OJD) in merino sheep run under Australian pastoral conditions. On each of three farms experiencing significant OJD losses (5-15% per annum), 200 merino lambs (age 1-4 months) were vaccinated, and 200 lambs were left unvaccinated. Animal assessments and sample collections were conducted twice yearly until 4 or 5 years of age. The impact of vaccination on mortality rate, faecal shedding of M. a. paratuberculosis (by pooled and individual faecal culture), liveweight, wool productivity, vaccine injection site lesions and cellular (BOVIGAM) and humoral (PARACHEK) immunity was examined. Vaccination stimulated cell-mediated and humoral immune responses, reduced mortalities due to OJD by 90% and delayed faecal shedding for the first year post-vaccination. Thereafter, the prevalence of shedders among vaccinates was reduced by 90%. The numbers of M. a. paratuberculosis excreted by the vaccinated groups were also reduced by at least 90% at most sampling times. However, high levels of excretion by vaccinates occurred on some occasions, and although only 7 of 600 vaccinates died from OJD, all 7 had multibacillary lesions. Thus there remains a risk that some vaccinated sheep will transfer the disease. Small reductions in liveweight were found in vaccinated lambs in the first year, but there was little effect on wool production. Vaccine injection site lesions were detected in almost 50% of sheep after 2 months, and these persisted for at least 4 years in 20-25% of vaccinates. Data from this trial enabled the registration of Gudair in Australia in 2002 and underpins the pivotal role of vaccination in the current management of OJD.

Phylogenetic transitions from oviparity to viviparity in reptiles generally have occurred in cold climates, apparently driven by selective advantages accruing from maternal regulation of incubation temperature. But why, then, are viviparous reptiles so successful in tropical climates? Viviparity might enhance fitness in the tropics via the same pathway as in the temperate zone, if pregnant female reptiles in the tropics maintain more stable temperatures than are available in nests (Shine's maternal manipulation hypothesis). Alternatively, viviparity might succeed in the tropics for entirely different reasons than apply in the temperate zone. Our data support the maternal manipulation hypothesis. In a laboratory thermal gradient, pregnant death adders (Acanthophis praelongus) from tropical Australia maintained less variable body temperatures (but similar mean temperatures) than did nonpregnant females. Females kept at a diel range of 25-31 degrees C (as selected by pregnant females) gave birth earlier and produced larger offspring (greater body length and head size) than did females kept at 23-33 degrees C (as selected by nonpregnant snakes). Larger body size enhanced offspring recapture rates (presumably reflecting survival rates) in the field. Thus, even in the tropics, reproducing female reptiles manipulate the thermal regimes experienced by their developing embryos in ways that enhance the fitness of their offspring. This similarity across climatic zones suggests that a single general hypothesis--maternal manipulation of thermal conditions for embryogenesis--may explain the selective advantage of viviparity in tropical as well as cold-climate reptiles.

The contents of eggs and neonates of the Australian skinks, Lampropholis guichenoti and L. delicata, are described and compared to allow interpretation of nutrient utilisation by the developing embryo. Even though the females are the same size, L. guichenoti lay smaller clutches of larger eggs (egg contents=41.6+/-1.2 mg dry mass) than L. delicata (26.6+/-2.8 mg). The energy density is the same for eggs (30.5+/-0.9 J/g ash-free dry mass for L. guichenoti and 29.9+/-1.1 J/mg for L. delicata) and neonates (22.5+/-1.3 J/mg for L. guichenoti and 23.5+/-0.4 J/mg for L. delicata) between species. The amount of nitrogen (protein) in neonates is only slightly lower than that in eggs, whereas there is a large and significant decline in total lipids. Thus, like some other skinks, protein is a source of metabolic energy during embryogenesis, although not as important as lipid. Triacylglycerol is the major lipid component of the eggs (80% of total lipid), with phospholipid forming only approximately 10% of the total lipid. The fatty acid profile of the phospholipid is distinguished by a high proportion of arachidonic acid (8%), a significant proportion of eicosapentaenoic acid (2-4%) and a relatively low proportion of docosahexaenoic acid (2-3%) compared to chickens. Eggs of both species have remarkably low concentrations of free cholesterol compared to other amniote eggs (0.7% for L. guichenoti and 1.3% for L. delicata). The loss of lipid during embryonic development is almost entirely due to the selective utilisation of yolk triacylglycerol, presumably for energy. By contrast, the amount of phospholipid recovered from the neonates was the same as that originally in the eggs. Moreover, significantly more total cholesterol was present in the neonates than in the eggs, suggesting that biosynthesis of additional cholesterol occurred during development. The phospholipids of the neonates contain higher proportions of arachidonic (11-12%) and docosahexaenoic (8%) acids than the phospholipids of the eggs. Eicosapentaenoic acid is less prevalent in phospholipids in neonates than in eggs. Neonates of both species contain significantly more calcium than the fresh egg contents (L. guichenoti, eggs 0.303+/-0.051 mg, neonates 0.641+/-0.047 mg; L. delicata, eggs 0.187+/-0.013 mg, neonates 0.435+/-0.033 mg), presumably as a result of resorption of calcium from the eggshell. Interestingly, there is also significantly more sodium in neonates than in the contents of fresh eggs (L. guichenoti, eggs 0.094+/-0.010 mg, neonates 0.184+/-0.011 mg; L. delicata, eggs 0.084+/-0.011 mg, neonates 0.151+/-0.010 mg). There is no significant difference in the content of potassium and magnesium in eggs and neonates of either species. Although the fresh eggs of L. delicata have a significantly higher sodium concentration than L. guichenoti, there is no difference in the concentrations of calcium, magnesium, potassium or sodium in the neonates of the two species.

This is the first report of the isolation of Actinobacillus suis in association with significant disease among preweaned pigs in Australia. Sudden deaths occurred in preweaned piglets at one facility and enlarged joints, particularly the stifles and tarsi, occurred at another. Isolates with the biochemical phenotype and apx genotype profile of A suis were cultured from affected piglets. Both facilities were of high health status and one had undergone a recent depopulation, disinfection and sow repopulation process. Reviewing initial reports of A suis disease overseas, it is apparent that outbreaks occurred sporadically in various locations, with disease occurring among the herds involved for some months only, before development of immunity. A suis disease is now considered an emerging disease on high health status farms.

We studied the control of salt gland secretion in hatchling Chelonia mydas. The threshold salt load to activate salt secretion was between 400 mumol NaCl 100 g bodymass (BM)-1 and 600 mumol NaCl 100 g BM-1, which caused an increase in plasma sodium concentration of 13% to 19%. Following a salt load of 2700 mumol NaCl 100 g BM-1, salt gland secretion commenced in 12 +/- 1.3 min and reached maximal secretory concentration within 2-7 min. Maximal secretory rate of a single gland averaged 415 mumol Na 100 g BM-1 h-1. Plasma sodium concentration and total osmotic concentration after salt loading were significantly higher than pretreatment values within 2 min. Adrenalin (25 micrograms kg BM-1) and the cholinergic agonist methacholine (1 mg kg BM-1) inhibited salt gland activity. Atropine (10 mg kg BM-1) reversed methacholine inhibition and stimulated salt gland secretion when administered with a subthreshold salt load. Arginine vasotocin produced a transient reduction in sodium secretion by the active gland, while atrial natriuretic factor, vasoactive intestinal peptide and neuropeptide Y had no measurable effect on any aspect of salt gland secretion. Our results demonstrated that secretion of the salt gland in C. mydas can be modified by neural and hormonal chemicals in vivo and that the cholinergic and adrenergic stimulation of an exocrine gland do not appear to have the typical, antagonist actions on the chelonian salt gland.

Baboons are widely used in biomedical research. Although it is widely held that Papio hamadryas breed well in captivity, each established colony has a different reproductive success often hypothesised to be due to husbandry practices. The National Baboon Colony in Australia is a unique colony that houses Papio hamadryas to mimic that structure seen in the wild. In this article; we have analysed their reproductive parameters and neonatal outcomes. The success of the colony husbandry practices was demonstrated by lack of maternal mortality, low foetal morbidity, and known maternal and paternal linage.

The thymus has been an enigmatic organ for centuries. Its true function was revealed only in 1961 when it was shown to be responsible for the proper development of the immune system. This finding has revolutionized the science of immunology and has led to a better understanding of the mechanisms involved in resistance to infections and of the pathogenesis of autoimmune and immunodeficiency diseases.

The ultrastructure of the olfactory apparatus of three newborn marsupial species, the northern native cat, the brushtail possum, and the northern brown bandicoot, were examined. The olfactory epithelium and olfactory bulbs were at a similar stage of development in all three species. Receptor cells with cilia were observed, and although the olfactory system undergoes further differentiation during pouch life and although the olfactory epithelium and bulb of the newborn differs from that of the adult, these facts do not preclude the ability of the newborn to detect smell. The presence of touch receptors around the mouth region and of sensory cells within the olfactory epithelium would suggest that touch and smell are two of the senses allowing the newborn marsupial to reach the pouch.

One hundred and forty-seven newborn lambs with congenital defects of the respiratory tract were examined during a 3-year investigation into the causes of perinatal lamb mortality. Respiratory defects were found in 3.3% of the 4,417 lambs examined and in one-third (36.6%) of the 401 congenitally malformed lambs. All the defects were secondary to other more extensive malformations. The upper respiratory tract was involved 3 times more than the lower tract. Males were involved more than females (4:3). The upper tract defects were harelip, cleft palate, atelorrhinia, arrhinia, proboscis, fused nostrils and choanal atresia. One of the facial clefts was a rare median harelip associated with cleft palate and fused nostrils. The lower tract defects were pulmonary agenesis, hypoplasia and duplication. The 2 most common defects were choanal atresia and secondary pulmonary hypoplasia. It was concluded that primary defects of the respiratory tract of sheep are rare and that secondary defects are relatively common.

A trial was carried out to determine whether selenium responsive unthriftiness existed on a property in the Strathbogie ranges of Central Victoria where unthriftiness of young sheep has been a problem for 10 to 20 years. White muscle disease had been diagnosed on the property in the previous year and on other properties in the area. Eighty Merino ewes and lambs were allotted to one of 4 groups in a 2 x 2 factorial designed trial in which sodium selenite (0.1 mg/kg) was given orally to ewes and/or lambs at marking time and to treated lambs at 3 monthly intervals thereafter. Selenium treatment of the ewes had no significant effect on subsequent lamb performance. Selenium treatment of the lambs produced significant responses: mortality in treated groups was 0% compared with 17.5% in untreated groups; body weight gains were 1.9 kg higher at both weaning and one year of age in treated than in untreated lambs; mean fleece weight was 14.4% higher in treated lambs and they produced 39% more wool than the surviving untreated lambs.

Vibrionic abortion was diagnosed in sheep on 48 occasions between 1963-65 and 3 of these were associated with other major abortion pathogens. The outbreaks were scattered throughout the agricultural area of Western Australia. Time-of-death of 91 infected lambs was: ante-parturient death 50.5%, parturient death 13.2% and post-parturient death 36.3% (deaths occurring immediately after death 28.6%, deaths delayed after death 2.2%, and late post-parturient death 5.5%). The majority of lambs had gross lesions, mainly subcutaneous oedema and excess fluid and fibrin in the serous cavities. The characteristic gross liver foci were present in 37.4% of the infected lambs examined. Seven lambs with signs of starvation had liver lesions: necrotic foci (6) and hepatomegaly (1); Campylobacter fetus subsp. intestinalis was recovered from the liver and/or gall bladder of each of the lambs. Epizootiological observations were reported including outbreaks under hot semi-arid conditions.

The development of coccidial infections in 21 free-ranging, unweaned beef calves from birth to 8 months was investigated by examining faecal samples for oocysts. Most calves commenced shedding oocysts within a month of birth, and had shed all nine species identified by 3-4 months. Oocysts were shed by three calves as young as 12 and 13 days. The oocysts species shed earliest, and the commonest thereafter, were Eimeria bovis, E. ellipsoidalis and E. zuernii. Although several oocyst counts between 5.0 X 10(3) and 114.0 X 10(3)g-1 of faeces of these potentially pathogenic species were recorded there was no clinical disease. Some calves shed oocysts approximately four times more frequently than others, and individual species counts greater than or equal to 5.0 X 10(3)g-1 were confined to 10 of the calves. Intermittent oocyst shedding continued throughout the study with a similar distribution of oocyst species from all calves.

Four hundred and one malformed lambs were examined during a 3-year investigation into the causes of perinatal lamb mortality. Frequence of involvement of the various body systems was: musculo-skeletal 55.4%, digestive 12.7%, cardiovascular 9.7%, uro-genital 7.1%, nervous 6.0%, special senses 3.5%, integument 3.2%, and endocrine 1.5%. A third of the defects (32.9%) involved more than one body system. There was a sex difference of 3 males: 2 females. The common defects in the lambs autopsied in order of frequence were: agnathia, atresia ani, cardiac defects, arthrogryposis, micrognathia, scrotal bifurcation, embryonic duplications, hernias, meningocele, and perosomus elumbis. Agnathia, atresia ani and persistent umbilical haemorrhage appeared to be hereditary. There was no relationship between congenital defects and the time of lambing and phytoestrogens.

Listeric abortion was diagnosed in sheep on 14 occasions between 1963-65, and 4 of these were associated with other major abortion pathogens. Except for infection in one district, the outbreaks were scattered sporadically over the southern agricultural area. The diagnosis in 1963 was the first time listeriosis had been found in animals or man in Western Australia. L. monocytogenes was readily recovered in pure culture from all organs and sites cultured. All the strains were serotype 5 Ivanov, with a distinctive double zone of haemolysis. The time-of-death of the 40 infected lambs was: ante-parturient death 50%, parturient death 10% and post-parturient death 40%. Three-quarters of the lambs had gross lesions, the most consistent being small necrotic foci in the liver. Typically, lambs with congenital listeriosis had subcutaneous oedema, hydrothorax, hydroperitoneum, distended abdomen, enlarged pale bronze-red friable livers with small necrotic foci, small abomasal erosions, increased yellow-orange mucoid meconium and enlarged mesenteric lymph nodes. The finding of small yellowish, necrotic foci in the liver, small abomasal erosions and yellow-orange meconium in an aborted lamb was considered to be almost pathognomonic for listeriosis. The origin of these outbreaks was unknown. No evidence of Listeria was found in 61 specimens from 7 species of native fauna caught in the infected areas. Epizootiological observations are reported. No cases of neuro-listeriosis were observed.

The occurrence of infections associated with perinatal mortality was investigated. In 1970, carcasses from 94 flocks distributed throughout Victoria were examined by microbiological and histopathological techniques. Carcasses from 4 of the same flocks were similarly examined in 1971. Widespread occurrence of Listeria monocytogenes and Campylobacter fetus was demonstrated with L. monocytogenes being recognised in 25% of the flocks examined. No other bacterial pathogens commonly associated with ovine perinatal mortality were isolated, but adequate techniques for recognition of Toxoplasma gondii were not used. E. coli was isolated from a majority of the carcasses and in heavy pure culture from the liver of 26 cases. Evidence of non-specific bacterial infection was recognised histopathologically in carcasses from 30% of flocks in which specific infection was not recognised. Specific infections were demonstrated culturally or histologically in 16% of the 582 carcasses submitted to detailed laboratory examination. The reported findings suggest that further investigation into the incidence of specific congenital infections is required.

The livers from 16,776 calves 1 to 3 weeks of age slaughtered at Shepparton abattoirs were examined for gross evidence of infection with Fasciola hepatica. Those livers with thickened bile ducts were examined for the presence of liver fluke by slicing. One hundred and eight F. hepatica were collected from 84 of these livers, giving a minimum prevalence rate of prenatal infection of calves of 0.5%. These results are discussed in context with reports from other countries.