The use of a penetrative captive bolt device during the killing of farmed saltwater crocodiles (Crocodylus porosus).

Killing of farmed saltwater crocodiles involve stunning with a penetrative captive bolt device, followed by a cut across the nape of the neck and physical destruction of the brain to ensure death. This study was a welfare-based assessment of the use of a penetrative captive bolt device in saltwater crocodiles, to determine whether it satisfies the criteria of a humane stunning method and can be regarded as a direct killing method without the need for the application of an adjunct method. Methods used were electroencephalogram (EEG), observation of post-stun behavior, and postmortem examination of gross pathology of the cranium and brain. 30 of 30 animals, demonstrated immediate and irreversible loss of consciousness. There was extensive damage to the brain in all animals, deemed to be inconsistent with cortical function and possible recovery. The CASH Special 0.22 penetrative captive bolt pistol (1.25 grain cartridge), applied to the top of the cranial plate, produced immediate and irreversible unconsciousness in all the animals studied. This method satisfies animal welfare expectations, providing crocodile processors with a technique that contributes to a humane killing process.

Evaluation of a commercial electrical stunning method for farmed grower saltwater crocodiles (Crocodylus porosus) using non-invasive EEG measurements.

The aim of this study was to assess welfare outcomes of electrical stunning as a means of restraint in farmed grower saltwater crocodiles (Crocodylus porosus). Physical handling of a stunned, unconscious crocodile is far safer for the operator than handling a fully conscious animal. Electroencephalogram (EEG) was recorded before and after the application of electrical stunning at 50 Hz or 400 Hz using an electrical stunner applied to the cranial plate (Position 1: P1-50 Hz; n = 31, P1-400 Hz; n = 29) or immediately behind the skull (Position 2: P2-50 Hz; n = 29; P2-400 Hz; n = 30). For all electrical stuns, percentage total EEG power in a 10-s epoch decreased in the alpha and beta frequency bands; and increased in the delta and lower frequencies bands. All electrical stuns resulted in increased strength of signal, based on the quadratic mean EEG power in all frequency bands of the EEG. Greatest change in power occurred in the delta frequency band, with P1-50 Hz. This was greater than with P2-50 Hz; while decibel change using 400 Hz at either position was intermediate and not significantly different from either. Application of either electrical stunner at position 1 resulted in seizure-like activity and activation in low frequencies, but at position 2 this was not consistent across all animals. The ability of the electrical stunning equipment to consistently induce recoverable unconsciousness could be ranked in decreasing order as: P1-50 Hz > P1-400 Hz = P2-50 Hz > P2-400 Hz. Based on behavioural observations, all animals in the study appeared to stunned however evaluation of duration of EEG changes indicates that use of the electrical stunning equipment at 50 Hz would allow some margin for inaccuracies in tong placement, while achieving a consistently reliable stun.

Associations between immune competence phenotype and feedlot health and productivity in Angus cattle.

Genetic strategies aimed at improving general immune competence (IC) have the potential to reduce the incidence and severity of disease in beef production systems, with resulting benefits of improved animal health and welfare and reduced reliance on antibiotics to prevent and treat disease. Implementation of such strategies first requires that methodologies be developed to phenotype animals for IC and demonstration that these phenotypes are associated with health outcomes. We have developed a methodology to identify IC phenotypes in beef steers during the yard weaning period, which is both practical to apply on-farm and does not restrict the future sale of tested animals. In the current study, a total of 838 Angus steers, previously IC phenotyped at weaning, were categorized as low (n = 98), average (n = 653), or high (n = 88) for the IC phenotype. Detailed health and productivity data were collected on all steers during feedlot finishing, and associations between IC phenotype, health outcomes, and productivity were investigated. A favorable association between IC phenotype and number of mortalities during feedlot finishing was observed with higher mortalities recorded in low IC steers (6.1%) as compared with average (1.2%, P < 0.001) or high (0%, P = 0.018) IC steers. Disease incidence was numerically highest in low IC steers (15.3 cases/100 animals) and similar in average IC steers (10.1 cases/100 animals) and high IC steers (10.2 cases/100 animals); however, differences between groups were not significant. No significant influence of IC phenotype on average daily gain was observed, suggesting that selection for improved IC is unlikely to incur a significant penalty to production. The potential economic benefits of selecting for IC in the feedlot production environment were calculated. Health-associated costs were calculated as the sum of lost production costs, lost capital investment costs, and disease treatment costs. Based on these calculations, health-associated costs were estimated at AUS$103/head in low IC steers, AUS$25/head in average IC steers, and AUS$4/head in high IC steers, respectively. These findings suggest that selection for IC has the potential to reduce mortalities during feedlot finishing and, as a consequence, improve the health and welfare of cattle in the feedlot production environment and reduce health-associated costs incurred by feedlot operators.

Efficacy of precisely injected single local bolus of lignocaine for alleviation of behavioural responses to pain during tail docking and castration of lambs with rubber rings.

Delivery of local anaesthetic at the time of castration and tail docking (marking) could improve welfare outcomes in lambs. This study examined pain responses in lambs marked using rubber rings, with or without local anaesthetic precision injected using the Numnuts® instrument. On each of two commercial farms, 150 prime lambs aged 4 to 10 weeks, balanced for sex, were randomly allocated to 3 treatments: handled in a lambing cradle (Sham), handled and marked with rubber rings (Ring) or handled and marked with rubber rings and treated with 30 mg lignocaine using the Numnuts® instrument (NNLA). Time to mother up (one trial site only), acute pain related behaviours at 5, 20, 35 and 50 min, and postures at 10 min intervals from 60 to 180 min were recorded. NNLA lambs tended to mother up more quickly than Ring lambs (P = 0.09), and more slowly (P = 0.07) than Sham lambs. Acute pain behaviours were significantly more frequent in Ring and NNLA than Sham (P < 0.001) from 5 to 50 min. NNLA was significantly lower than Ring at 5 min (P < 0.001) and 20 min (P = 0.001). Ring and NNLA did not differ at 35 or 50 min. Abnormal postures were higher in Ring and NNLA than Sham at 60, 70, 80, 90 and 150 min (P < 0.048). Ring and NNLA did not differ at any time point between 60 and 180 min. Delivery of lignocaine with the Numnuts® instrument improved welfare outcome of lambs during the acute pain response caused by castration and tail docking with rubber rings.

Immune competence traits assessed during the stress of weaning are heritable and favorably genetically correlated with temperament traits in Angus cattle1.

Selection for production traits with little or no emphasis on health-related traits has the potential to increase susceptibility to disease in food-producing animals. A possible genetic strategy to mitigate such effects is to include both production and health traits in the breeding objective when selecting animals. For this to occur, reliable methodologies are required to assess beneficial health traits, such as the immune capacity of animals. We describe here a methodology to assess the immune competence of beef cattle which is both practical to apply on farm and does not restrict the future sale of tested animals. The methodology also accommodates variation in prior vaccination history of cohorts of animals being tested. In the present study, the immune competence phenotype of 1,100 Angus calves was assessed during yard weaning. Genetic parameters associated with immune competence traits were estimated and associations between immune competence, temperament, and stress-coping ability traits were investigated. Results suggested that immune competence traits, related to an animal's ability to mount both antibody and cell-mediated immune responses, are moderately heritable (h2 = 0.32 ± 0.09 and 0.27 ± 0.08, respectively) and favorably genetically correlated with the temperament trait, flight time (r = 0.63 ± 0.31 and 0.60 ± 0.29 with antibody and cell-mediated immune responses, respectively). Development of methodologies to assess the immune competence phenotype of beef cattle is a critical first step in the establishment of genetic selection strategies aimed at improving the general disease resistance of beef herds. Strategies aimed at reducing the incidence of disease in beef cattle are expected to significantly improve animal health and welfare, reduce reliance on the use of antibiotics to treat disease, and reduce disease-associated costs incurred by producers.

Development of a modified molecular diagnostic procedure for the identification and quantification of naturally occurring strongylid larvae on pastures.

A molecular procedure was developed to detect and quantify larvae of different strongylid parasite species recovered from pasture samples. Two lamb flocks (L and S) grazed separate paddocks with different natural larvae challenges (one low [Paddock L] and one high [Paddock S] challenge) on a commercial farm in Western Australia. Pasture samples were collected and analysed for larvae on 9 separate occasions from each paddock. Pregnant Merino ewes were sampled on 3 separate occasions (2 pre-partum and 1 post-partum). Following lambing, 203 female crossbred lambs were identified, from which faecal samples were collected across five separate samplings. Lamb production and faecal attributes were recorded. Genomic DNA was extracted directly from lamb faeces, in addition to the genomic DNA extracts from strongylid larval species recovered from pastures. Faecal worm egg counts (FWECs) were undertaken. Species-specific qPCRs and conventional PCRs (ITS-2 nuclear ribosomal DNA) were used to screen samples for strongylid species (Teladorsagia circumcincta, Trichostrongylus spp., Haemonchus contortus, Chabertia ovina and Oesophagostomum venulosum). Negative correlations (r(2)>0.91) were found between qPCR C(q) values and log-transformed pasture larval counts for Trichostrongylus spp. and T. circumcincta. Moderate levels of agreement between pasture larval counts and qPCR results were observed (67%). A clear difference in pasture larval challenge levels was observed between the two flocks using both qPCR and conventional pasture larval counts. It is difficult to draw conclusions on the production performances of lambs from the two experimental flocks, as no further replicates were able to be conducted following this experiment. Flock L had higher dressing percentages than Flock S (P=0.038), along with significantly higher faecal consistency and breech fleece faecal soiling scores at successive samplings. The molecular procedures utilised in this study have the potential to be beneficial for livestock grazing management strategies and parasite surveillance, however further investigation is necessary before they can become part of routine diagnostics.

Altered fatty acid metabolism in long duration road transport: An NMR-based metabonomics study in sheep.

The physical, endocrine, and metabolic responses of livestock to road transport have been evaluated by conventional hematological and biochemistry parameters for more than 20 years. However, these measures are relatively insensitive to subtle metabolic adaptations. We applied NMR-based metabonomics to assess system-wide metabolic responses as expressed in urine and serum of a large cohort of animals (n = 80) subjected to 12 and 48 h road transport. The profiling of (1)H NMR spectra revealed that the transported animals experienced altered gut and energy metabolism, muscle catabolism, and possibly a renal response. The animals transported for 48 h exhibited a deeper metabolic response to the transport event and a complex and expanded metabolic trajectory over the 72 h recovery period. Intriguingly, excretion of acyl glycines and a dicarboxylic acid was observed after transport and during recovery, implicating peroxisomal fatty acid oxidation as a metabolic response to transport-induced stress.