Quantifying Transmission of Campylobacter jejuni in Commercial Broiler Flocks

Since meat from poultry colonized with Campylobacter spp. is a major cause of bacterial gastroenteritis, human exposure should be reduced by, among other things, prevention of colonization of broiler flocks. To obtain more insight into possible sources of introduction of Campylobacter into broiler flocks, it is essential to estimate the moment that the first bird in a flock is colonized. If the rate of transmission within a flock were known, such an estimate could be determined from the change in the prevalence of colonized birds in a flock over time. The aim of this study was to determine the rate of transmission of Campylobacter using field data gathered for 5 years for Australian broiler flocks. We used unique sampling data for 42 Campylobacter jejuni-colonized flocks and estimated the transmission rate, which is defined as the number of secondary infections caused by one colonized bird per day. The estimate was 2.37 +/- 0.295 infections per infectious bird per day, which implies that in our study population colonized flocks consisting of 20,000 broilers would have an increase in within-flock prevalence to 95% within 4.4 to 7.2 days after colonization of the first broiler. Using Bayesian analysis, the moment of colonization of the first bird in a flock was estimated to be from 21 days of age onward in all flocks in the study. This study provides an important quantitative estimate of the rate of transmission of Campylobacter in broiler flocks, which could be helpful in future studies on the epidemiology of Campylobacter in the field.

Post capture necrosis of the feet caused by soft-catch traps – incidents, cause and prevention.

When recapturing satellite collared wild dogs that had been trapped one month previous in padded foothold traps, we noticed varying degrees of pitting on the pads of their trapped paw. Veterinary advice, based on images taken of the injuries, suggests that the necrosis was caused by vascular compromise. Five of six dingoes we recaptured had varying degrees of necrosis restricted only to the trapped foot and ranging from single 5 mm holes to 25% sections of the toe pads missing or deformed, including loss of nails. The traps used were rubber-padded, two–coiled, Victor Soft Catch #3 traps. The springs are not standard Victor springs but were Beefer springs; these modifications slightly increase trap speed and the jaw pressure on the trapped foot. Despite this modification the spring pressure is still relatively mild in comparison to conventional long spring or four-coiled wild dog traps. The five wild dogs developing necrosis were trapped in November 2006 at 5-6 months of age. Traps were checked each morning so the dogs were unlikely to have been restrained in the trap for more than 12 hours. All dogs exhibited a small degree of paw damage at capture which presented itself as a swollen paw and compression at the capture point. In contrast, eight wild dogs, 7-8 month-old, were captured two months later in February. Upon their release, on advice from a veterinarian, we massaged the trapped foot to get blood flow back in to the foot and applied a bruise treatment (Heparinoid 8.33 mg/ml) to assist restoring blood flow. These animals were subsequently recaptured several months later and showed no signs of necrosis. While post-capture foot injuries are unlikely to be an issue in conventional control programs where the animal is immediately destroyed, caution needs to be used when releasing accidentally captured domestic dogs or research animals captured in rubber-padded traps. We have demonstrated that 7-8 month old dogs can be trapped and released without any evidence of subsequent necrosis following minimal veterinary treatment. We suspect that the rubber padding on traps may increase the tourniquet effect by wrapping around the paw and recommend the evaluation of offset laminated steel jaw traps as an alternative. Offset laminated steel jaw traps have been shown to be relatively humane producing as few foot injuries as rubber-jawed traps.

Sustaining productivity of tropical red snappers using new monitoring and reference points

OBJECTIVES: 1. Analyse current monitoring and logbook data sets, as well as survey and other information,to establish whether these data provide sufficient power to develop critical indicators of fishery performance. 2. Provide a risk analysis that examines the use of age structure and catch rate information for development of critical indicators, and response rules for those criteria, in the absence of other fishery information. 3. Develop a monitoring program that uses commercial vessels from the fishery to provide independent data.

Male traits and herd reproductive capability in tropical beef cattle. 2. Genetic parameters of bull traits

A total of 4063 young bulls of two tropical genotypes (1639 Brahman and 2424 Tropical Composite) raised in northern Australia were evaluated for a comprehensive range of production and reproduction traits up to 24 months of age. Prior to weaning, peripheral blood concentrations of luteinising hormone (LH) and inhibin were measured at 4 months of age. At weaning (6 months) blood insulin-like growth factor-1 (IGF-I) and flight time were recorded. Body composition traits of fat depth and eye-muscle area were determined by ultrasonography at 15 months of age when additional measurements of liveweight, hip height and body condition score were recorded. Bull breeding soundness was evaluated at similar to 12, 18 and 24 months of age when measurements of scrotal circumference, sheath score, semen mass activity, progressive motility of individual sperm and percent morphologically normal sperm were recorded. Magnitude of heritability and genetic correlations changed across time for some traits. Heritability of LH, inhibin, IGF-I and of 18-month scrotal circumference, mass activity, progressive motility and percent normal sperm was 0.31, 0.74, 0.44, 0.75, 0.24, 0.15 and 0.25, respectively, for Brahmans and 0.48, 0.72, 0.36, 0.43, 0.13, 0.15 and 0.20, respectively, for Tropical Composites. Inhibin and IGF-I had moderate genetic association with percent normal sperm at 24 months in Brahmans but low to negligible associations in Tropical Composites. Body condition score in Brahmans and sperm motility (mass and individual) traits in both genotypes had moderate to strong genetic correlation with percent normal sperm and may prove useful candidates for indirect selection. There is scope to increase scrotal circumference by selection and this will be associated with favourable correlated responses of improved semen quality in both genotypes. The lack of genetic antagonism among bull traits indicates that selection for improved semen quality will not adversely affect other production traits.

Liveweight prediction from hip height, condition score, fetal age and breed in tropical female cattle

Hip height, body condition, subcutaneous fat, eye muscle area, percentage Bos taurus, fetal age and diet digestibility data were collected at 17 372 assessments on 2181 Brahman and tropical composite (average 28% Brahman) female cattle aged between 0.5 and 7.5 years of age at five sites across Queensland. The study validated the subtraction of previously published estimates of gravid uterine weight to correct liveweight to the non-pregnant status. Hip height and liveweight were linearly related (Brahman: P<0.001, R-2 = 58%; tropical composite P<0.001, R-2 = 67%). Liveweight varied by 12-14% per body condition score (5-point scale) as cows differed from moderate condition (P<0.01). Parallel effects were also found due to subcutaneous rump fat depth and eye muscle area, which were highly correlated with each other and body condition score (r = 0.7-0.8). Liveweight differed from average by 1.65-1.66% per mm of rump fat depth and 0.71-0.76% per cm(2) of eye muscle area (P<0.01). Estimated dry matter digestibility of pasture consumed had no consistent effect in predicting liveweight and was therefore excluded from final models. A method developed to estimate full liveweight of post-weaning age female beef cattle from the other measures taken predicted liveweight to within 10 and 23% of that recorded for 65 and 95% of cases, respectively. For a 95% chance of predicted group average liveweight (body condition score used) being within 5, 4, 3, 2 and 1% of actual group average liveweight required 23, 36, 62, 137 and 521 females, respectively, if precision and accuracy of measurements matches that used in the research. Non-pregnant Bos taurus female cattle were calculated to be 10-40% heavier than Brahmans at the same hip height and body condition, indicating a substantial conformational difference. The liveweight prediction method was applied to a validation population of 83 unrelated groups of cattle weighed in extensive commercial situations on 119 days over 18 months (20 917 assessments). Liveweight prediction in the validation population exceeded average recorded liveweight for weigh groups by an average of 19 kg (similar to 6%) demonstrating the difficulty of achieving accurate and precise animal measurements under extensive commercial grazing conditions.

The integrity of sperm chromatin in young tropical composite bulls

Sperm chromatin fragmentation is associated with subfertility, but its relationship with age progression in young bulls is poorly understood. The objective was to assess sperm chromatin fragmentation during the early post-pubertal development of 20 tropical composite bulls, using a sperm chromatin structure assay (SCSA) and sperm-bos-halomax (SBH). Bulls were subjected to bull breeding soundness evaluation (BBSE) at mean ages of 13, 18, and 24 mo. Traits measured included liveweight (WT), body condition score (BCS) and scrotal circumference (SC). Semen samples were collected by electroejaculation and assessed for mass activity (MA), motility (Mot), concentration (conc), sperm morphology and chromatin fragmentation. Concentration (r = 0.34, P = 0.0076), Mot (r = 0.36, P = 0.0041) and percentage of morphologic normal sperm (percent normal sperm (PNS); r = 0.31, P = 0.0132) were positively correlated with age. The percentage of sperm with proximal droplets (PD) was negatively correlated with age (r = -0.28, P = 0.0348), whereas neither SCSA nor SBH results were significantly correlated with age. The percentage of sperm with chromatin fragmentation using SCSA was correlated with PNS (r = -0.53, P < 0.0001), the percentage of sperm with head abnormalities (r = 0.68, P < 0.0001) and the percentage of intact sperm (Int) with SBH (r = -0.26, P = 0.0456). In summary, for assessment of sperm chromatin fragmentation, samples could be equally collected at 13, 18 or 24 mo of age, as results did not vary with age. (c) 2012 Elsevier Inc. All rights reserved.

Performance of Pinus elliottii, Pinus caribaea, their F-1, F-2 and backcross hybrids and Pinus taeda to 10 years in the Mesopotamia region, Argentina

Performances of Pinus taxa were studied to 10 years of age in two trials in each of Misiones and Entre Rios provinces across the Mesopotamia region of Argentina. Taxa comprised 22 populations from sources in Argentina, Australia, Brazil and Zimbabwe including Pinus elliottii var. elliottii (Pee), Pinus caribaea var. hondurensis (Pch), their four, inter-specific hybrids (F-1, F-2 and backcrosses from F-1 to Pch and to Pee-all as broadly based bulks); other Pee and Pinus taeda (Pt) comprised narrower or unspecified bulks. Variable numbers of taxa were missing at each site. Mean survival across sites at age 10 years ranged 53.2-91.3% averaging 74.2%. Analysis of variance of plot means indicated population effect was statistically significant (p < 0.05) for all or most growth and quality traits at all sites. However, significant differences from the nominated check seedlot at the Entre Rios sites (Pee, Australia) were extremely rare, while quite common at the northern, Misiones sites (check seedlot a Pt population). In the Misiones trials, F-1, F-2 and both backcross hybrids showed better stem straightness than Pee and Pt from Argentina, generally with statistically significant differences (p < 0.05). Pt showed lowest forking scores (desirable). Taxon x environment interaction was statistically significant (p < 0.01) for growth traits only (p > 0.05). However, this interaction contributed an average of only 34.1% of the taxon variance suggesting a lack of practical importance. Taxa most suitable for deployment in the Mesopotamia region, Argentina are suggested.

Detection of a putative hemolysin operon, hhdBA, of Haemophilus parasuis from pigs with Glasser disease

The aim of the current study was to investigate whether polymerase chain reaction amplification of 16S ribosomal (r)RNA and a putative hemolysin gene operon, hhdBA, can be used to monitor live pigs for the presence of Haemophilus parasuis and predict the virulence of the strains present. Nasal cavity swabs were taken from 30 live, healthy, 1- to 8-week-old pigs on a weekly cycle from a commercial Thai nursery pig herd. A total of 27 of these pigs (90%) tested positive for H. parasuis as early as week 1 of age. None of the H. parasuis-positive samples from healthy pigs was positive for the hhdBA genes. At the same pig nursery, swab samples from nasal cavity, tonsil, trachea, and lung, and exudate samples from pleural/peritoneal cavity were taken from 30 dead pigs displaying typical pathological lesions consistent with Glasser disease. Twenty-two of 140 samples (15.7%) taken from 30 diseased pigs yielded a positive result for H. parasuis. Samples from the exudate (27%) yielded the most positive results, followed by lung, tracheal swab, tonsil, and nasal swab, respectively. Out of 22 positive samples, 12 samples (54.5%) harbored hhdA and/or hhdB genes. Detection rates of hhdA were higher than hhdB. None of the H. parasuis-positive samples taken from nasal cavity of diseased pigs tested positive for hhdBA genes. More work is required to determine if the detection of hhdBA genes is useful for identifying the virulence potential of H. parasuis field isolates.

Profiling of carotenoids and antioxidant capacity of microalgae from subtropical coastal and brackish waters

Carotenoids are associated with various health benefits, such as prevention of age-related macular degeneration, cataract, certain cancers, rheumatoid arthritis, muscular dystrophy and cardiovascular problems. As microalgae contain considerable amounts of carotenoids, there is a need to find species with high carotenoid content. Out of hundreds of Australian isolates, twelve microalgal species were screened for carotenoid profiles, carotenoid productivity, and in vitro antioxidant capacity (total phenolic content (TPC) and ORAC). The top four carotenoid producers at 4.68-6.88 mg/g dry weight (DW) were Dunaliella salina, Tetraselmis suecica, Isochrysis galbana, and Pavlova salina. TPC was low, with D. salina possessing the highest TPC (1.54 mg Gallic Acid Equivalents/g DW) and ORAC (577 μmol Trolox Equivalents/g DW). Results indicate that T. suecica, D. salina, P. salina and I. galbana could be further developed for commercial carotenoid production.

Multi-trait assessment of early-in-life female, male and genomic measures for use in genetic selection to improve female reproductive performance of Brahman cattle

Early-in-life female and male measures with potential to be practical genetic indicators were chosen from earlier analyses and examined together with genomic measures for multi-trait use to improve female reproduction of Brahman cattle. Combinations of measures were evaluated on the genetic gains expected from selection of sires and dams for each of age at puberty (AGECL, i.e. first observation of a corpus luteum), lactation anoestrous interval in 3-year-old cows (LAI), and lifetime annual weaning rate (LAWR, i.e. the weaning rate of cows based on the number of annual matings they experienced over six possible matings). Selection was on an index of comparable records for each combination. Selection intensities were less than theoretically possible but assumed a concerted selection effort was able to be made across the Brahman breed. The results suggested that substantial genetic gains could be possible but need to be confirmed in other data. The estimated increase in LAWR in 10 years, for combinations without or with genomic measures, ranged from 8 to 12 calves weaned per 100 cows from selection of sires, and from 12 to 15 calves weaned per 100 cows from selection of sires and dams. Corresponding reductions in LAI were 60-103 days or 94-136 days, and those for AGECL were 95-125 or 141-176 days, respectively. Coat score (a measure of the sleekness or wooliness of the coat) and hip height in females, and preputial eversion and liveweight in males, were measures that may warrant wider recording for Brahman female reproduction genetic evaluation. Pregnancy-test outcomes from Matings 1 and 2 also should be recorded. Percentage normal sperm may be important to record for reducing LAI and scrotal size and serum insulin-like growth factor-I concentration in heifers at 18 months for reducing AGECL. Use of a genomic estimated breeding value (EBV) in combination with other measures added to genetic gains, especially at genomic EBV accuracies of 40%. Accuracies of genomic EBVs needed to approach 60% for the genomic EBV to be the most important contributor to gains in the combinations of measures studied.

Scrotal circumference of Australian beef bulls

Normal range for scrotal circumference in Australian beef bulls was established using more than 300,000 measurements of breed, management group, age, liveweight, and scrotal circumference. The data used were derived from Australian bull breeders and two large research projects in northern Australia. Most bulls were within 250 to 750 kg liveweight and 300 to 750 days of age. The differences between breeds and variances within breeds were higher when scrotal circumference was predicted from age rather than liveweight, because of variance in growth rates. The average standard deviation for predicted scrotal circumference from liveweight and age was 25 and 30 mm, respectively. Scrotal circumference by liveweight relationships have a similar pattern across all breeds, except in Waygu, with a 50 to 70 mm range in average scrotal circumference at liveweights between 250 and 750 kg. Temperate breed bulls tended to have higher scrotal circumference at the same liveweight than tropically adapted breeds. Five groupings of common beef breeds in Australian were identified, within which there were similar predictions of scrotal circumference from liveweight. It was concluded that liveweight and breed are required to identify whether scrotal circumference is within normal range for Australian beef bulls that experience a wide range of nutritional conditions.

Genetics of early and lifetime annual reproductive performance in cows of two tropical beef genotypes in northern Australia

Reproduction records from 2137 cows first mated at 2 years of age and recorded through to 8.5 years of age were used to study the genetics of early and lifetime reproductive performance from two genotypes (1020 Brahman and 1117 Tropical Composite) in tropical Australian production systems. Regular ultrasound scanning of the reproductive tract, coupled with full recording of mating, calving and weaning histories, allowed a comprehensive evaluation of a range of reproductive traits. Results showed components traits of early reproductive performance had moderate to high heritabilities, especially in Brahmans. The heritability of lactation anoestrous interval in 3-year-old cows was 0.51 +/- 0.18 and 0.26 +/- 0.11 for Brahman and Tropical Composite, respectively. Heritabilities of binary reproductive output traits (conception rate, pregnancy rate, calving rate and weaning rate) from first and second matings were generally moderate to high on the underlying scale. Estimates ranged from 0.15 to 0.69 in Brahman and 0.15 to 0.34 in Tropical Composite, but were considerably lower when expressed on the observed scale, particularly for those traits with high mean levels. Heritabilities of lifetime reproduction traits were low, with estimates of 0.11 +/- 0.06 and 0.07 +/- 0.06 for lifetime annual weaning rate in Brahman and Tropical Composite, respectively. Significant differences in mean reproductive performance were observed between the two genotypes, especially for traits associated with anoestrus in first-lactation cows. Genetic correlations between early-in-life reproductive measures and lifetime reproduction traits were moderate to high. Genetic correlations between lactation anoestrous interval and lifetime annual weaning rate were -0.62 +/- 0.24 in Brahman and -0.87 +/- 0.32 in Tropical Composite. The results emphasise the substantial opportunity that exists to genetically improve weaning rates in tropical beef cattle breeds by focusing recording and selection on early-in-life female reproduction traits, particularly in Brahman for traits associated with lactation anoestrus.

Effect of drying, storage temperature and air exposure on astaxanthin stability from Haematococcus pluvialis

Astaxanthin is a powerful antioxidant with various health benefits such as prevention of age-related macular degeneration and improvement of the immune system, liver and heart function. To improve the post-harvesting stability of astaxanthin used in food, feed and nutraceutical industries, the biomass of the high astaxanthin producing alga Haematococcus pluvialis was dried by spray- or freeze-drying and under vacuum or air at − 20 °C to 37 °C for 20 weeks. Freeze-drying led to 41 higher astaxanthin recovery compared to commonly-used spray-drying. Low storage temperature (− 20 °C, 4 °C) and vacuum-packing also showed higher astaxanthin stability with as little as 12.3 ± 3.1 degradation during 20 weeks of storage. Cost-benefit analysis showed that freeze-drying followed by vacuum-packed storage at − 20 °C can generate AUD600 higher profit compared to spray-drying from 100 kg H. pluvialis powder. Therefore, freeze-drying can be suggested as a mild and more profitable method for ensuring longer shelf life of astaxanthin from H. pluvialis.