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Chlamydiae are obligate intracellular bacteria that infect a broad range of host species, including sheep. Two species of Chlamydia infect sheep, C. abortus, which is a major cause of abortion in both sheep and goats, and C. pecorum, which causes pneumonia, arthritis/polyarthritis, encephalomyelitis, conjunctivitis, enteritis, abortion and metritis and infertility in domestic ruminants and pigs. The prevalence of faecal shedding of C. pecorum is relatively common amongst lambs in Australia. The aim of the work presented here was to use qPCR to determine the prevalence of C. pecorum in synovial samples obtained from abnormal joints trimmed from lamb carcases at one abattoir in southern Australia. The study included 53,131 carcases screened for arthritis, of which 369 had at least one abnormal joint trimmed. One hundred and forty eight trimmed joints were undamaged and suitable for PCR testing. The prevalence of C. pecorum in synovial tissue collected from the abnormal joints was 6.1% and the bacterial concentration ranged from 6 × 103 to 7.6 × 105/g of synovial tissue. Five of the positive joint samples were from carcases that had one joint trimmed for arthritis and four were from carcases from which two joints had been trimmed. None of the carcases from which the positive joint samples originated were condemned. The average arthritis trim weight of the carcases from which synovial tissue tested positive for C. pecorum was 1.112 kg (95% confidence interval 0.637-1.586 kg) and this did not differ from the carcases from which synovial tissue was not positive for C. pecorum. (mean 0.997 kg, 95% confidence interval 0.840-1.154 kg). Further research is required to determine the on-farm production losses associated with C. pecorum infection in Australian lambs.

Arthritis is commonly observed in lambs at slaughter, resulting in losses due to carcase downgrading, trimming or condemnation. The condition arises on-farm and is thought to be influenced by a number of predisposing factors, which vary in their ability to be addressed by sheep producers. The aim of this study was to investigate whether there is a link between tail length and arthritis in lambs. If there is, leaving a longer tail stump when docking may be a cost-effective way of reducing the prevalence of joint infections in lambs. The study was conducted at an abattoir in South Australia and included 63,287 carcases. This study found a correlation between short-docked tails (fewer than three coccygeal vertebrae remaining) and bacterial arthritis in lambs. Other risk factors for arthritis included breed and the regional source of the lambs, but not age. The constraints of data collection within the abattoir did not allow the effects of tail docking method, sex or whether male lambs had been castrated on the prevalence of bacterial arthritis to be determined. The bacterium most commonly isolated from abnormal joints was Erysipelothrix rhusiopathiae, followed by Streptococcus spp., including Streptococcus suis.

The objective of the present cross-sectional study was to determine whether antibodies against equine infectious anemia (EIA), equine viral arteritis (EVA), and Burkholderia mallei in horses from Jordan can be detected at all; moreover, the study aimed at identifying potential risk factors associated with a positive serologic result. Data related to management of each farm and individual horses were collected. Commercially available serologic kits were used to detect the presence of serum antibodies in 254 horses. Potential risk factors associated with seropositivity were evaluated using the one-sided chi square tests of association. All serum samples were negative for equine infectious anemia virus and glanders. Therefore, no risk factors could be determined. A total of 6 (2.4%) sera had antibodies to equine arteritis virus (EAV). There was a significant ( P P P

Context The most common way of pricing beef carcasses is through a price grid. Most processors make greater profit from higher-quality carcasses, which are those with higher meat yield and eating quality. Aims The aim of this study was to calculate the value of diverse carcasses and compare pricing mechanisms on their ability to discriminate variation in meat yield and predicted eating quality. Methods Hereford cross steer carcasses (153) were boned out to record saleable meat and yield. Six methods were used to calculate carcass price (AU$/kg). All were adjusted to the same average carcass value to allow comparisons, assuming that the overall payment does not change, but comparing the effect of having greater premiums and discounts. The six prices were based on a commercial grid, grid plus eating quality premium, yield of saleable meat only (constant price for all saleable meat), yield with eating quality premium, then the yield prices with optimum (quadratic) weight and fatness penalties based on grid optimums. Key results Measurements of meat quality (eye muscle area and marble score) or saleable meat yield accounted for no variation in the grid price. However, measurement of yield accounted for substantial variation in prices calculated from yield and eating quality. Conclusions The current grids do not encourage high-quality meat production and, assuming that yield and eating quality are important to processors, an actual measurement of yield is crucial to guide processing decisions (e.g. cutting plans) to maximise carcass value and feed market signals back to beef producers. Implications Improved measurement of meat yield is required if carcass prices are to reflect carcass quality or the potential value captured.

Context Ecchymosis is an undesirable appearance in meat caused by small bleeds from capillaries broken during the slaughter process. These lesions are heavily trimmed during processing, incurring labour costs and yield losses. Aims To estimate the prevalence of ecchymosis in a South Australian abattoir and investigate potential predisposing factors. Methods A generalised linear mixed model estimated the effects of breed, age, slaughter shift (morning or afternoon), kill date, direct or market consignment, hot standard carcase weight (HSCW, kg), deviation from lot average carcase weight (ZHSCW, standard units), palpated fat score (mm) and time in lairage (h) on the prevalence of ecchymosis. Over 7 days, 12286 lamb and 3802 mutton carcases from 82 properties were scored (0, 1) for ecchymosis. Key results Lambs had a higher prevalence of ecchymosis (14%) than did mutton (1%; P < 0.001), with significant variation between lines of lambs (P < 0.001). Considering lambs only, kill date (P < 0.01), time in lairage (P < 0.001), and the quadratic terms of HSCW (P < 0.001) and ZHSCW (P < 0.01) affected the prevalence of ecchymosis. Conclusions Ecchymosis had a significant prevalence in lambs only. The time lambs spend in lairage and their bodyweight may be predisposing factors for ecchymosis before slaughter and warrant further investigation. Implications The interaction of size and weight extremeness appeared to predispose lambs to developing ecchymosis at slaughter. Farm of origin was another identified risk factor (management group). Whether it was size and extremeness influencing body composition or other mechanisms involved in vascular integrity, is not known. Further research is required to identify these mechanisms so as to establish breeding and management guidelines that will decrease the likelihood and cost of ecchymosis in lambs. Ecchymosis remains poorly understood, but fractured capillaries indicate a weakness in vascular tissue. Given the present study included over 12000 observations in 7 days, ecchymosis in lambs could be used as a model to study vascular weakness in humans.

This study aimed to determine the seroprevalence and to identify risk factors associated with Neospora spp. infection in horses in Jordan. Management related data were collected from each farm and individual horses. Sera from 227 horses from 5 of 6 climatic regions in Jordan were analyzed for the presence of antibodies to Neospora spp. by ELISA kit. The study was performed during spring of 2010. The association between seropositivity and risk factors was analyzed. A total of 7 (3%) of 227 sera had antibodies for Neospora spp. There was a significant regional difference (P=0.018) between the 5 climatic regions. Positive cases were located in Amman and Irbid, while the other regions (Zarqa, Jordan Valley, and Wadi Mousa) had zero prevalence. The use of anthelmintics at least once a year resulted in a significant reduction of the seroprevalence to Neospora spp. (1.6% vs 9.8%). However, this might be a phenomenon by chance and a better hygiene since owners can invest in anthelmintics. Other risk factors such as age, gender, breed, usage, body condition score, grazing, presence of other animals mixed with the horses in the same property, and a history of previous diseases were not significantly associated with the seroprevalence to Neospora spp. infection. This is the first study to report on the presence of Neospora seropositive horses in Jordan. Further studies are warranted to better understand the role of certain risk factors in the transmission of Neospora spp. among horse population and to determine which Neospora spp. are responsible for the infection.

This study was conducted to evaluate the combined effect of high pressure (HP) with the addition of soy sauce and/or olive oil on the quality and safety of chicken breast meats. Samples were cut into 100 g pieces and 10% (w/w) of soy sauce (SS), 10% (w/w) of olive oil (OO), and a mixture of both 5% of soy sauce and 5% olive oil (w/w) (SO) were pressurized into meat with high pressure at 300 or 600 MPa. Cooking loss was lower in OO samples than SS samples. With increased pressure to 600 MPa, the oleic acid content of OO samples increased. The total unsaturated fatty acids were the highest in SO and OO 600 MPa samples. Lipid oxidation was retarded by addition of olive oil combined with HP. The addition of olive oil and soy sauce followed by HP decreased the amount of volatile basic nitrogen during storage and reduced the population of pathogens. Sensory evaluation indicated that the addition of olive oil enhanced the overall acceptance and willingness to buy. In conclusion, the combination of HP with the addition of soy sauce and/or olive oil is an effective technology that can improve chemical, health, sensory qualities and safety of chicken breast.

Bacterial arthritis in sheep is a painful and debilitating condition that is widespread across all sheep-raising regions and climatic zones of Australia. At slaughter, bacterial arthritis in sheep causes economic losses through the condemnation of all or parts of the carcass, as specified in the Australian Standard for the Hygienic Production and Transportation of Meat and Meat Products for Human Consumption. In this study, we investigated the economic cost of arthritis in lambs presenting to an abattoir in southern Australia using a combination of the prevalence of arthritis detected during meat inspection, condemnation rates, trim weight and carcass weight, and fat measurements. Data were collected on 354 lines of lambs representing 63287 carcasses. One hundred and sixty nine consignments, or approximately one-half of the consignments, had at least one carcass with arthritis/polyarthritis detected by meat inspection personnel. Four hundred and twenty-two, or 0.7%, of the carcasses had arthritis/polyarthritis in at least one joint. When arthritis was present, on average 2.0% of the line was affected. Three carcasses with arthritis were condemned and the remainder trimmed, with an average trim weight of 0.7 kg. In addition, arthritis reduced the growth of lambs by 1.2 kg hot standard carcass weight, approximately 2.7 kg liveweight (assuming 45% dressing percentage) and reduced fat cover by 1.8 mm.

High hydrostatic pressure (300, 450 and 600 MPa) was used to investigate its effect on microbial population, meat quality and sensory characteristics of chicken breast fillets. Pressures of 450 and 600 MPa almost completely eliminated all the 3 major pathogens Salmonella typhimurium (KCTC 1925), Escherichia coli (KCTC 1682), and Listeria monocytogenes (KCTC 3569) and therefore improved safety of chicken breast fillets. The 600 MPa treatment reduced bacteria count by 6–8 log (CFU/g) for 7–14 days, and the 450 MPa treatment reduced bacteria count by 4–8 log (CFU/g) for 3–14 days, depending on the microorganism. The increased pressure had an impact on flavour, aroma strength and juiciness. The 300 MPa pressure significantly reduced flavour, aroma strength and juiciness, and 450 MPa produced breast fillets with the weakest aroma. Increasing pressure increased cooking loss and colour by increasing L*, a* and b* values. Moreover, elevated pressure increased hardness, cohesiveness, gumminess and chewiness, as well as improved freshness of meat by reducing VBN. Pressure of 450 MPa and higher induced lipid oxidation. The results demonstrate that high pressure treatment is an effective technology in reducing bacterial spoilage and extending shelf-life of chicken breast fillet, however it may have a negative impact on some quality and sensory characteristics.

Between 1997 and 1999 a comprehensive survey of airborne pollutant concentrations within, and emissions from, 160 Australian piggery buildings was undertaken. The primary aim of the study was to model the concentrations and emissions of different airborne pollutants and thus identify potential reduction techniques. The main factors identified as significantly influencing airborne pollutant concentrations were building type, pen hygiene, pig flow management, seasons, building volume, ventilation airflow rate, air temperature, relative humidity, and farm size (as expressed by number of sows on site). These effects were included in comprehensive statistical models to explain the variation in measured concentrations and emission rates. The models developed were validated and fine-tuned using the “leave-one-out” cross-validation technique. This article details the validation technique used that was aimed to maximise the value of available experimental data and further improves the practicality of the models developed. The main result of the study was the development of an improved model. The study results, and the resulting prediction models, should help improve air quality in piggery buildings by providing decision makers with an awareness of the environmental conditions inside and outside of piggery buildings. In turn, that should lead to improvements in the health and welfare of pigs and piggery staff and the sustainability of the piggery operations.

A solid-flow sensor, designed to measure the amount of feed delivered to individual feeders in livestock buildings was built, fine-tuned and tested for accuracy under realistic field conditions. The design is based on 'solid-flow' measurement technology that enabled the research team to build a sensor that is cost effective, compact and robust. The sensor was designed to be easily introduced to existing feed supply systems. Innovative aspects of the software and hardware components of the instrument enabled the sensor to accurately estimate the amount of feed supplied through the feed pipe. The sensor was tested a number of times in an experimental feed distribution system under conditions that mimicked the commercial environment. The sensor precision was also specifically evaluated in relation to changed humidity conditions and diet composition. During the field tests, the sensor-estimated feed amount was found to be in agreement with the actual feed delivered within the accepted limit (0.5 kg). The field tests results provided evidence that the system can perform well under field conditions with an accuracy of around 2-4% or 0.1-0.3 kg.

High concentrations of airborne particles in poultry building can affect the environmental sustainability of the operation, production efficiency, and the health and welfare of the birds. In addition, sub-optimal air quality can create occupational health and safety (OH&S) risks for farm workers. It was hypothesised that a systematic study of the relationship between air quality and housing features could identify practical ways of reducing the concentration of airborne pollutants found in poultry buildings. To achieve this aim the concentration of total viable (airborne bacteria), inhalable and respirable particles were measured in the airspace of 17 commercial broiler buildings between October 2001 and January 2002. The overall mean total viable, inhalable and respirable particle concentrations measured were 5.27 × 105 cfu m−3, 4.32 mg m−3, 0.84 mg m−3, respectively. The characteristics of the buildings surveyed were documented at the time of sampling and a multi-factorial general linear modelling approach was used to identify the statistically significant factors influencing the concentration of airborne particles. The viable airborne particle concentration was influenced by the cleaning regime (p = 0.067), ventilation type (p = 0.006), age of buildings (p = 0.006), bedding type (p = 0.075) and temperature (p = 0.002). The type of ventilation (p = 0.008), bedding (p = 0.045), temperature (p = 0.023) and building age (p = 0.04) had significant effects on inhalable particle concentrations. Four factors were identified as having a significant affect on respirable particle concentrations in broiler buildings. These were cleaning or not cleaning between batches of birds (p = 0.055), biological loading (kg birds per building airspace) of buildings (p = 0.008), ventilation levels (p = 0.005) and humidity (p = 0.016). The positive effects of cleaning and tunnel ventilation were clearly identified during the study and the fact that older buildings appear to have reduced airborne particle concentrations is also noteworthy. Further refinement and implementation of these aspects of broiler building management would lead to innovative airborne particle reduction opportunities. In turn, an improvement in air quality within poultry buildings should enhance production efficiency, the health of birds and could potentially reduce OH&S related health problems in humans.

Between autumn 1997 and autumn 1999, we measured ventilation rates (using a CO2 balance method), air temperatures, and relative humidity (using self-contained dataloggers with built-in sensors) in 160 pig housing facilities in Queensland, South Australia, Victoria, and Western Australia, in each case over a 60 h period. In some buildings, the internal air velocities above the animals were also recorded. While the monitoring instruments were being set up, a detailed questionnaire was used to collect data on major housing features and management factors. This information was statistically analyzed to quantify the effects of housing and management factors on the resulting environment conditions using a multifactorial analysis. The overall mean air temperature, relative humidity, internal air velocity, and ventilation rate were 20.3 degrees C, 58.9%, 0.12 m s(-1), and 663.9 m3 h(-1) 500 kg(-1) live weight, respectively, across all buildings. Internal building temperature and humidity were affected statistically by the type of insulation material used, the classification of buildings, and external climatic conditions. Ventilation rates were primarily affected by the type of ventilation system used, height (size) of ventilation openings, stocking density (kg m(-3)), and length, width, and height of buildings. These findings should aid the development of strategies for the industry to improve environmental control in piggery buildings.

The Biometry Hub, a statistics research and consulting group in an agricultural science school, has commenced a project to enhance the statistical capacity of graduates in agricultural sciences. The project engages with students undertaking research projects as they are completing their undergraduate degrees and considering their careers, possibly in research. This group is motivated learners focused on delivering outcomes in solving real-life problems, and respond well to opportunities for their broad professional development. The project will help them become familiar with the culture of cross-disciplinary collaboration, an essential component of modern agricultural research.

Postnatal myofibre characteristics and muscle mass are largely determined during fetal development and may be significantly affected by epigenetic parent-of-origin effects. However, data on such effects in prenatal muscle development that could help understand unexplained variation in postnatal muscle traits are lacking. In a bovine model we studied effects of distinct maternal and paternal genomes, fetal sex, and non-genetic maternal effects on fetal myofibre characteristics and muscle mass. Data from 73 fetuses (Day153, 54% term) of four genetic groups with purebred and reciprocal cross Angus and Brahman genetics were analyzed using general linear models. Parental genomes explained the greatest proportion of variation in myofibre size of Musculus semitendinosus (80-96%) and in absolute and relative weights of M. supraspinatus, M. longissimus dorsi, M. quadriceps femoris and M. semimembranosus (82-89% and 56-93%, respectively). Paternal genome in interaction with maternal genome (P

There has been a growing interest in improving air quality within livestock buildings. However, the influence of housing and management factors on air exchange rates and indoor gas concentrations is not well understood. The aim of this study was to determine the effects of housing and management factors on the concentrations of carbon dioxide (CO(2)) and air exchange rates in 160 representative Australian pig buildings. CO(2) concentrations were measured, air changes per hour (ACH) were estimated using a CO(2) balance method, and structural and management parameters were recorded. The mean CO(2) concentration measured was 858 ppm and a mean air exchange rate of 22.8 ACH was estimated. The analysis showed that CO(2) concentrations were affected by the type of building, season, control of the wall and ridge vents, ceiling height, size of the wall vents and height of the ridge vents. Weaner buildings had the highest CO(2) concentrations while deep-bedding shelters had the lowest. Winter CO(2) concentrations were higher in all buildings compared to summer. Buildings with automated ridge ventilation control had the lowest CO(2) concentrations. The wall ventilation inlet height was negatively correlated with CO(2) concentration. Air exchange rates were primarily affected by the type of ventilation, inlet height, stocking density, and building width and height. In conclusion, the equable Australian climate has allowed the construction of cheaper pig buildings, which provide an adequate environment for pig production, although these buildings may not always provide an optimal environment for pig production. (C) 2011 IAgrE. Published by Elsevier Ltd. All rights reserved.

The internal concentrations and emission rates of ammonia (NH3), total bacteria, respirable endotoxins, and inhalable and respirable particles were monitored in 160 piggery buildings in four states of Australia (Queensland, Victoria, Western Australia, and South Australia) between autumn 1997 and autumn 1999. Emissions were calculated for individual buildings as a product of internal concentration and ventilation rate, which were estimated by a carbon dioxide balance method. Relative humidity and temperature were also measured. The overall mean emission rates of NH3, total bacteria, respirable endotoxins, inhalable particles, and respirable particles per 500 kg live weight from Australian piggery buildings were 1442.5 mg h(-1), 82.2 x 10(6) cfu h(-1), 20.1 x 10(3) EU h(-1), 1306.7 mg h(-1), and 254.7 mg h(-1), respectively. Internal concentrations of key airborne pollutants have been reported in companion articles. Building characteristics and management systems used in the piggeries were documented at the time of sampling and used in the subsequent statistical modeling of variations in pollutant emission rates. The emissions model used all statistically significant factors identified during prior modeling conducted for individual pollutant concentrations and ventilation airflow. The identification of highly significant factors affecting emission rates and internal concentrations should aid the development of strategies for the industry to reduce emission rates from individual buildings, thus improving the environmental performance of piggery operations. In the second part of the article, specific recommendations are made based on the overall study results.

We undertook a literature search related to pig production facilities with two major aims: first, to review all the likely benefits that might be gained from air quality improvements; and second, to review previous research that had identified statistically significant factors affecting airborne pollutants and environmental parameters, so that these factors could be considered in a multifactorial analysis aimed at explaining variations in air pollutant concentrations. Ammonia, carbon dioxide, viable bacteria, endotoxins, and inhalable and respirable particles were identified as major airborne pollutants in the review. We found that high concentrations of airborne pollutants in livestock buildings could increase occupational health and safety risks, compromise the health, welfare, and production efficiency of animals, and affect the environment. Therefore, improving air quality could reduce environmental damage and improve animal and worker health. To achieve a reduction in pollutant concentrations, a better understanding of the factors influencing airborne pollutant concentrations in piggery buildings is required. Most of the work done previously has used simple correlation matrices to identify relationships between key factors and pollutant concentrations, without taking into consideration multifactorial effects simultaneously in a model. However, our review of this prior knowledge was the first important step toward developing a more inclusive statistical model. This review identified a number of candidate risk factors, which we then took into consideration during the development of multifactorial statistical models. We used a general linear model (GLM) to model measured internal concentrations, emissions, and environmental parameters in order to predict and potentially control the building environment.

The concentrations of total airborne bacteria, respirable endotoxins, ammonia, and respirable and inhalable particles were monitored in 160 piggery buildings in Australia between autumn 1997 and autumn 1999. The overall mean airborne bacteria, respirable endotoxins, ammonia (NH3), and inhalable and respirable particle concentrations measured were 1.17 x 10(5) cfu m(-3), 33.1 EU m(-3), 3.7 ppm, 1.74 mg m(-3), and 0.26 mg m(-3), respectively. The characteristics of the buildings and management systems used were documented at the time of sampling. A multifactorial general linear model (GLM) statistical procedure was used to analyze the effects of housing and management factors on the concentrations of the airborne pollutants. Both airborne bacteria and respirable endotoxin concentrations were affected by building classification (type), and respirable endotoxin concentrations were positively correlated with increasing humidity. The concentrations of airborne bacteria increased as the level of pen hygiene (cleanliness) decreased. The NH3 concentrations were primarily affected by level of pen hygiene, building volume, pig flow management, and season. Building classification, pig flow management, season, building volume, ventilation rates, and temperature affected inhalable particle concentrations. Respirable particle concentrations were primarily affected by building classification, pen hygiene, pig flow management, season, ventilation rates, temperature, and humidity. These findings suggest that environmental improvement strategies (such as improved cleaning, ventilation, and temperature control) are likely to reduce airborne pollutant concentrations in pig buildings and in the environment, thus improving the health and welfare of both pigs and farm staff.

The placenta, a major determinant of fetal growth in eutherians, facilitates maternal-fetal cross talk and mediates programming of postnatal phenotype via genetic and epigenetic mechanisms. However, magnitude and specificity of effects of maternal and paternal genomes on placental and fetal phenotype and their relationships are unclear. Using an outbred bovine intra-species model with well-defined Bos taurus taurus and Bos taurus indicus maternal and paternal genetics, we generated purebred and reciprocal cross fetuses (Animal Ethics No. S-094-2005) to dissect and quantify effects of parental genomes, fetal sex, and nongenetic maternal effects (maternal weight and post-conception maternal weight gain) on 41 gross and histomorphological feto-placental parameters. Analysis of data from 73 fetuses recovered at midgestation (Day 153) with general linear models (Xiang et al. 2014 JBMR http://dx.doi.org/10.1002/jbmr.2263) using the GLM procedure of R version 22.14 (R Development Core Team, Vienna, Austria) revealed that maternal and paternal genome combined explained the highest proportion of variation (47.2–99.5%) in 30 investigated parameters with significant (P

During a 4-year period (1994–97) of the Australian ‘Southern Crossbreeding Project’, mature Hereford cows (n = 637) were mated to 97 sires from 7 breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin and Belgian Blue), resulting in 1334 calves. Heifers were slaughtered at around 16 months and steers at 23 months. The objective of the study was to quantify between- and within-breed genetic variation for numerous production and quality traits in a southern-Australian production system. Calf survival, birth weight and carcass production traits (carcass weight, fat depth, loin eye area, intramuscular fat) were obtained from these cattle. The carcass traits were loge-transformed because of a scale effect on the variance. Data were analysed using multi-variate animal models containing fixed effects of sex with random effects of management group, sire breed and animal. In addition, birth month and age of dam were included as fixed effects for birth weight. Covariances between survival and other traits could not be estimated from the multi-variate model so they were estimated from a series of bi-variate models. On average, management group and sire breed accounted for similar proportions of variance. Heritability ranged from 0.14 (survival), 0.17 (intramuscular fat), 0.28 (loin eye area), 0.29 (P8 fat depth), 0.31 (birth weight) to 0.50 (carcass weight). In general, environmental (management and residual) correlations between meat (carcass weight and loin eye area) and fat traits (fat depth and intramuscular fat) were positive, but the genetic correlations (both between and within breed) were negative. Management and genetic (co)variation has been quantified and can facilitate production of calves with carcasses suitable for specific market requirements.