Repeatability of an attention bias test for sheep suggests variable influence of state and trait affect on behaviour.

Understanding the effects of repeated testing on behaviour is essential for behavioural tests that are re-applied to the same individuals for research and welfare assessment purposes. Assessing the repeatability of behaviour can also help us understand the influence of persistent traits vs transient states on animal responses during testing. This study examined the repeatability of behavioural responses in an attention bias test developed for sheep as a measure of affective state. Sheep were assessed in the attention bias test three times (n = 81 sheep), with testing occurring at intervals of 1 year then 2 weeks. During testing, individual sheep were exposed to a dog located behind a window for 3 s in a 4 × 4 m arena, then the dog was obscured from view, removed and sheep behaviours were recorded for 180 s. We hypothesised that behaviours in the test would have moderate-high repeatability but that the mean behavioural responses would change over consecutive trials as sheep habituated to the test environment. To estimate repeatability, data were modelled using restricted maximum likelihood linear mixed-effects models, fitting animal ID as a random effect. Vigilance behaviour, defined as having the head at or above shoulder height, was moderately repeatable (r = 0.58). Latency to eat (r = 0.20) and duration spent looking towards the previous location of the dog (attention to the dog wall) (r = 0.08) had low repeatability. Mean latency to eat did not differ significantly between trials (P = 0.2) and mean vigilance behaviour tended to decrease over the trials (P = 0.07). Mean duration of attention to the dog wall significantly decreased across the trials (P < 0.001), while mean zones crossed increased (P < 0.001), as did behaviours directed towards the exit door such as duration in proximity and pawing at the door. Overall, vigilance behaviour was moderately repeatable, suggesting it may have been driven by temperament or personality traits, while attention and feeding behaviours may have been more influenced by transient affective states or other factors, however further research is needed to better tease apart these potential effects. Sheep demonstrated some habituation to the test over consecutive trials. Care should therefore be taken during future application of the test to ensure all animals undergoing attention bias testing have equivalent experience for a valid interpretation of their relative behavioural responses.

Evaluating a novel analgesic strategy for ring castration of ram lambs.

OBJECTIVE: To evaluate the analgesic efficacy of the NSAIDs flunixin and meloxicam administered locally to the scrotum before ring castration. STUDY DESIGN: Randomised, controlled, prospective study. ANIMALS: Forty eight single born male Merino lambs. METHODS: Lambs, aged approximately 4 weeks, were allocated to four groups for castration. Groups were: sham control; castration + saline; castration + flunixin; castration + meloxicam. Drugs (5 mL) were administered subcutaneously around the circumference of the scrotum immediately before castration. Cortisol, rectal temperature, haematology and plasma haptoglobin were measured before and up to 48 hours after treatment. Behaviour recorded by video for 12 hours after treatment was classified as pain avoidance behaviours in the first hour and postural behaviours in three 4 hour intervals. RESULTS: Ring castration (saline group) induced a bi-phasic increase in cortisol with peaks at 90 minutes and 24 hours but no significant changes in haematology, haptoglobin or rectal temperature. Pain avoidance behaviours were increased and teat seeking decreased. Normal lying and normal standing postures were decreased and abnormal ventral lying, statue standing, abnormal standing and total abnormal postures increased. Flunixin decreased cortisol at 90 minutes (60.3 versus 117.3 nmol L(-1) ) and cortisol AUC (0-6 hours), decreased elevated leg movement (2.5 versus 5.4 events) and sum of pain avoidance behaviours (8.5 versus 16.7 events), improved time spent in normal ventral lying and decreased abnormal ventral lying and total abnormal postures compared to saline treated lambs. In a similar contrast, meloxicam caused non-significant decreases in cortisol at 90 minutes, cortisol AUC (0-6 hours) and pain avoidance behaviours, and significantly improved the postural behaviours normal ventral lying (26.7 versus 15.4%) and normal standing (13.9 versus 7.5%), and reduced abnormal standing and total abnormal postures. Physiological and behavioural responses associated with ring castration for both NSAID treatment groups were generally greater than sham controls. CONCLUSIONS AND CLINICAL RELEVANCE: Locally administered NSAIDs provided partial analgesia for ring castration.

Local Anesthetic Delivered with a Dual Action Ring and Injection Applicator Reduces the Acute Pain Response of Lambs during Tail Docking.

Docking the tail of lambs is a standard husbandry procedure and is achieved through several techniques including clamps, hot or cold knives and latex rings, the last of which is the most popular. All tail docking methods cause acute pain which can be reduced by application of local anesthetic, however precise anatomical injection for optimal efficacy requires considerable skill. This pen trial evaluated the ability of local anesthetic (LA) delivered with a dual function ring applicator/injector to alleviate acute tail docking pain. Thirty ewe lambs were assigned to one of three treatment groups (n = 10 per group): ring plus local anesthetic (Ring LA), ring only (Ring) and sham handled control (Sham). Lambs were videoed and their behavior categorized every five minutes for the first hour and every 10 min for the subsequent two hours after treatment. There was a significant effect (p < 0.001) of treatment on total active pain related behaviors in the first hour, with Ring lambs showing higher counts compared to Ring LA or Sham. Ring lambs also displayed a significantly higher count of combined abnormal postures (p < 0.001) than Ring LA or Sham lambs. Delivery of 1.5 mL of 2% lignocaine via the dual action device abolished abnormal behaviors and signs of pain in Ring LA lambs. However, lambs in the Ring LA group spent less time attempting to suckle compared to Ring and Sham lambs, suggesting that some residual discomfort remained.

Three Studies Evaluating the Potential for Lidocaine, Bupivacaine or Procaine to Reduce Pain-Related Behaviors following Ring Castration and/or Tail Docking in Lambs.

The use of local anesthesia at the time of ring castration and tail docking can improve lamb welfare. However, few local anesthetics are registered for sheep, and data on their duration of effect is limited. Three studies were conducted to evaluate the efficacy of procaine (P), lidocaine (L), and bupivacaine (B) in terms of observed alleviation of behavioral responses to castration and/or tail docking in 10-min blocks in the first 60 min post-treatment. In each study, comparisons were made between two groups of lambs castrated and/or tail docked with rubber rings and either receiving the agent using the NUMNUTS® instrument (N) or receiving no anesthetic agent (RR). Acute pain behavior was lower in NL (n = 28) than RRL (n = 15) males in the first 10 min post-procedure (p < 0.05); lower in NB (n = 16) than RRB (n = 16) males in periods 10-20 min (0.05 < p < 0.01), 20-30 min (p < 0.05) and 40-50 min (0.05 < p < 0.01); lower in NB (n = 16) than RRB (n = 16) females between 20 and 40 min post-procedure (0.05 < p < 0.01); lower in NP (n = 8) than RRP (n = 7) males in period 10-20 min (0.05 < p < 0.01), and lower in NP (n = 9) than RRP (n = 9) females in periods 0-10 min (0.05 < p < 0.01), and 10-40 min (p < 0.05). Benefits were modest, and the effects of procaine appear to last longer than lidocaine, while bupivacaine is slower to take effect than either procaine or lidocaine but may provide longer-lasting pain relief. The duration of action of local anesthetics is short in sheep, and detailed behavioral evaluations are required in the first hour post-procedure to establish efficacy.

Analgesia for Sheep in Commercial Production: Where to Next?

Increasing societal and customer pressure to provide animals with 'a life worth living' continues to apply pressure on livestock production industries to alleviate pain associated with husbandry practices, injury and illness. Over the past 15-20 years, there has been considerable research effort to understand and develop mitigation strategies for painful husbandry procedures in sheep, leading to the successful launch of analgesic approaches specific to sheep in a number of countries. However, even with multi-modal approaches to analgesia, using both local anaesthetic and non-steroidal anti-inflammatory drugs (NSAID), pain is not obliterated, and the challenge of pain mitigation and phasing out of painful husbandry practices remains. It is timely to review and reflect on progress to date in order to strategically focus on the most important challenges, and the avenues which offer the greatest potential to be incorporated into industry practice in a process of continuous improvement. A structured, systematic literature search was carried out, incorporating peer-reviewed scientific literature in the period 2000-2019. An enormous volume of research is underway, testament to the fact that we have not solved the pain and analgesia challenge for any species, including our own. This review has highlighted a number of potential areas for further research.

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.

A consideration of physiological regulation from the perspective of Bayesian enactivism.

How the animal regulates its internal environment is a central question in physiology. In recent years, the account of biological functions known as Bayesian enactivism has been extended from neuroscience to address processes of physiological regulation. Enactivism understands sensory action cycles of perception and behaviour to entail expectations of the causes of sensations received from the environment. Enactivism is Bayesian in that the organism strives to update expectations to better match the sensations it experiences through actions. The review starts with a brief examination of the historical development of the concepts of homeostasis, homeorhesis and allostasis. To better align the historical concepts of physiological regulation with Bayesian enactivism it is suggested that homeorhesis and allostasis function as opposing effectors modulating, respectively, robustness and plasticity of phenotype to render homeostatic balance of the animal with its changing environment. In this formulation, the expectations of the environment embedded within the form and functions of the animal that develop under homeorhetic control during morphogenesis and morphostasis are updated by allostasis to better match the animal's phenotype with its contemporary environment. Just as morphogens shape development and persistence of anatomical form during morphogenesis and morphostasis, anticipatory behaviours can be understood to structure the animal's pattern of environmental engagement in a manner that shapes the development and persistence of homeostasis. Further empirical and theoretical analyses should help clarify whether homeorhesis and allostasis are aspects of a common underlying process or are opposing effectors mediating a Bayesian dialogue between expectation and experience.

The Influence of Temperament on Body Temperature Response to Handling in Angus Cattle.

Previous studies have indicated that cattle with more excitable temperaments exhibit an increased stress response. The objective of this study was to investigate the relationship between temperament traits, handling, and stress-induced hyperthermia (SIH) in beef cattle. Rectal temperatures (TREC, °C) of 60 purebred Angus cattle (30 heifers, 30 steers; 235.2 ± 5.11 kg) were recorded at 20 s intervals from 30 min prior to handling until two hours post handling. All cattle were exposed to a standardized handling procedure consisting of (i) being restrained in a weighing box for 30 s; (ii) being held within the crush for 30 s; and then (iii) being restrained in a head bail for 60 s. Cattle temperaments were evaluated via three traits: (1) agitometer score (AG); (2) crush score (CS); and (3) flight speed (FS) during the handling procedure. Agitometer scores and FS measures were used to describe an AG category (AGCAT) and an FS category (FSCAT) that were used to classify animals into three temperament categories: 1, calm; 2, intermediate; and 3, temperamental. Pearson's correlation coefficients were used to evaluate the associations between (i) AG, CS, FS, and TREC 30 min prior to entry into the weighing box (T-30) and then at 1 min intervals between time of entry into the weighing box (T0) until 10 min post-weighing (T10); and (ii) the relationship between AG, CS, and FS. The relationship between TREC and temperament traits over the 2.5 h were modeled by using a first-order autoregressive repeated measures model. Flight speed had strong to moderate associations with TREC at T-30 (r ≥ 0.37; p ≤ 0.006) and between T0 and T10 (r ≥ 0.36; p ≤ 0.01). There were moderate associations amongst TREC between T0 and T10 and CS (r ≥ 0.31; p ≤ 0.01). A weak relationship existed with CS (r = 0.16; p = 0.16). There were no associations between AG and TREC at T-30 (r ≥ -0.15; p = 0.84) or between T0 and T10 (r ≤ 0.04; p ≥ 0.4). Rectal temperature, irrespective of sex and temperament traits, was influenced by time (p < 0.0001), and maximum TREC (39.3 ± 0.04 °C) occurred between 4 and 5.7 min after entry into the weighing box. In addition, CS (p = 0.007) influenced TREC in these cattle. There were also time × temperament trait × sex interactions with the CS (p = 0.0003) and FSCAT (p = 0.043) categories; however, time × temperament trait interactions were not statistically significant. Results from this study suggest that cattle with excitable temperaments, as evaluated by FS and CS, have a greater increase in TREC. In addition, these results suggest that a relationship exists between basal TREC and FS and CS. Together, these results highlight that temperament, as assessed by FS and CS, influences both basal TREC and the peak temperature recorded following handling but does not influence the magnitude of change in TREC post handling.

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.

A comparison of methods for preparing enriched populations of bovine spermatogonia.

The objective of the present study was to identify an efficient and practical enrichment method for bovine type A spermatogonia. Four different enrichment methods were compared: differential plating on laminin- or Datura stramonium agglutinin (DSA)-coated flasks, percoll-gradient isolation, magnetic-activated cell sorting (MACS) and fluorescence-activated cell sorting (FACS). The isolated cells were characterised with Dolichos biflorus agglutinin (DBA) lectin staining for type A spermatogonia and vimentin-antibody staining for Sertoli cells. A 2 x 2 factorial design was used to investigate the enrichment efficiency on laminin and DSA. In the laminin-enrichment groups, 2 h incubation in plates coated with 20 microg mL(-1) laminin yielded a 3.3-fold increase in DBA-positive cells in the adherent fraction, while overnight incubation in flasks coated with 20 microg mL(-1) DSA produced a 3.6-fold increase in the non-adherent fraction. However, the greatest enrichment (5.3-fold) of DBA-positive cells was obtained after 2 h incubation in control flasks (coated with bovine serum albumin). Percoll-gradient centrifugation yielded a 3-fold increase in DBA-positive cells. MACS results showed a 3.5- to 5-fold enrichment while FACS produced a 4-fold increase in DBA-positive cells. It is concluded that differential plating is a better method of recovering large numbers of type A spermatogonia for germ cell transplantation, while MACS or FACS can provide highly enriched viable type A spermatogonia for in vitro culture. Further, the combination of differential plating and other enrichment techniques may increase the purification efficiency of type A spermatogonia.

Chronic stress influences attentional and judgement bias and the activity of the HPA axis in sheep.

INTRODUCTION: Environmental challenges are part of everyday life for most domestic animals. However, very little is known about how animals cope emotionally and physiologically with cumulative challenges. This experiment aimed to determine the impact of long-term exposure to environmental challenges on the affective state and hypothalamic-pituitary-adrenal (HPA) axis responses to a subsequent additional acute shearing challenge. METHODS: Sheep were exposed to either a long-term environmental challenge (rest disruption and individual housing) in order to induce chronic stress (chronic stress group) or control conditions (group housing in a field with low stress handling and daily feed rewards, control group). Judgement and attention bias were assessed as measures of the emotional state following several days of the challenge or control treatment (pre-shearing tests). In addition, the responsiveness of the HPA-axis was evaluated using a combined Corticotropin Releasing Hormone and Arginine Vasopressin (CRH/AVP) challenge. Finally, all animals were exposed to an acute shearing challenge, then judgement bias (post-shearing test), HPA-axis and internal body temperature responses were determined. RESULTS: In the pre-shearing judgement bias test, the chronic stress group slightly increased optimism compared to the control treatment. In the attention bias test, the chronic stress group showed reduced vigilance behaviour towards a predator threat and a quicker approach to the food compared to the control treatment. The chronic stress group also had lower plasma ACTH concentrations in response to the CRH/AVP challenge compared to the control group, no differences in cortisol concentrations were found. In the post-shearing judgement bias test, differences in optimism were no longer evident between the chronic stress and control groups. Plasma ACTH concentrations and body temperatures showed a greater increase in response to shearing in the chronic stress group compared to the control group. CONCLUSION: Our results suggest that long-term exposure to challenges biased cognitive measures of the affective state towards an increased expectation of a reward and reduced attention towards a threat. The exaggerated ACTH responses in the chronic stress group may be indicative of HPA-axis dysregulation. Despite a period of challenge exposure in the chronic stress group, judgement bias responses to the shearing challenge were similar in the chronic stress and control groups; the reasons for this need further investigation. The altered affective state together with signs of HPA-axis dysregulation may indicate an increased risk of compromised welfare in animals exposed to long-term environmental challenges.

Production and active transport of immunoglobulins within the ruminant mammary gland.

The primary function of the mammary gland is to produce milk to feed the suckling young. In ruminants, ingestion of maternal antibodies in mammary secretions facilitates the transfer of passive immunity from mother to young, providing antibody-mediated immunity to protect the neonate against disease while their own immune system develops. Antibodies in mammary secretions also play a role in protecting the gland itself against infection. Here we provide a brief history of studies on immunoglobulins in ruminant mammary secretions and review recent findings describing the mechanisms by which antibody-producing plasmablasts are recruited to the gland and immunoglobulins are transported into ruminant mammary secretions. An improved understanding of the complex interaction of factors which regulate immunoglobulin production and transfer to the ruminant mammary gland may provide opportunities to enhance antibody concentrations in mammary secretions during normal lactation and in response to immunisation. Strategies aimed at increasing antibody concentrations in ruminant mammary secretions have the potential to improve the ability of animals to resist mammary infections, enhance the transfer of passive immunity from mother to young and increase the feasibility of harvesting antibodies from the mammary secretions for use in commercial therapeutic applications for humans and domesticated animals.

The influence of pharmacologically-induced affective states on attention bias in sheep.

When an individual attends to certain types of information more than others, the behavior is termed an attention bias. The occurrence of attention biases in humans and animals can depend on their affective states. Based on evidence from the human literature and prior studies in sheep, we hypothesized that an attention bias test could discriminate between pharmacologically-induced positive and negative affective states in sheep. The test measured allocation of attention between a threat and a positive stimulus using key measures of looking time and vigilance. Eighty 7-year-old Merino ewes were allocated to one of four treatment groups; Anxious (m-chlorophenylpiperazine), Calm (diazepam), Happy (morphine) and Control (saline). Drugs were administered 30 min prior to attention bias testing. The test was conducted in a 4 × 4.2 m arena with high opaque walls. An approximately life-size photograph of a sheep was positioned on one wall of the arena (positive stimulus). A small window with a retractable opaque cover was positioned on the opposite wall, behind which a dog was standing quietly (threat). The dog was visible for 3 s after a single sheep entered the arena, then the window was covered and the dog was removed. Sheep then remained in the arena for 3 min while behaviors were recorded. Key behaviors included time looking toward the dog wall or photo wall, duration of vigilance behavior and latency to become non-vigilant. In contrast with our hypothesis, no significant differences were found between treatment groups for duration of vigilance or looking behaviors, although Anxious sheep tended to be more vigilant than Control animals (P < 0.1) and had a longer latency to become non-vigilant (P < 0.001). A total of 24 of 80 animals were vigilant for the entire test duration. This censoring of data may explain why no differences were detected between groups for vigilance duration. Overall, a lack of difference between groups may suggest the test cannot discriminate positive and negative states in sheep. We suggest that the censoring of vigilance duration data, the use of insufficient drug doses, the potential influence of background noise and the age of the sheep may explain a lack of difference between groups. Due to these potential effects, it remains unclear whether the attention bias test can detect positive states in sheep.

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 method of measuring cellular stress in cattle and sheep.

In the current studies, flow cytometric methods were used to demonstrate that heat shock protein (hsp) 70 is constitutively expressed in ovine and bovine leukocytes but that the level of expression varies considerably between different leukocyte types and between species. We also show that expression of hsp70 is upregulated in response to an in vitro heat shock treatment. The optimal temperature for heat shock of leukocytes from sheep and cattle is 43.5 degrees C. In sheep and cattle, the relative susceptibility of leukocyte type to upregulation of hsp70 expression, as assayed as percent positive cells, by in vitro heat shock was cell type specific. Best results were obtained from fresh samples; after storage at room temperature for 24h upregulation was highly variable between animals and less than in fresh samples. These studies demonstrate that evaluation of leukocyte hsp70 expression by flow cytometry is a robust, reproducible method for use in the evaluation of cellular stress responses in cattle and sheep. The application of the methods described may be a valuable tool in assessing in vivo stress responses in livestock species.

Development of a faecal occult blood test to determine the severity of Haemonchus contortus infections in sheep.

Haemonchus contortus commences feeding on host blood by day 11 of infection, which leads to the presence of blood in the host's faeces. This study examined the capacity for a faecal occult blood (FOB) test to determine the severity of H. contortus infection in sheep at pasture, and to predict a rise in worm egg count (WEC) as infection matures. Diluted faeces were assayed with Bayer Hemastix and the change in colour of the reagent patch was scored on a 9-point scale from 1 (negative) to 5 in half unit increments. Performance of the test was compared with four benchmarks for severe infection: (1) WEC>2000 on test day; (2) WEC>2000 on test day or 3 days later; (3) WEC>2000 on test day or 3 or 7 days later; and (4) WEC>2000 on test day or 3, 7 or 10 days later. For a FOB score > or = 3, the frequency of false positive results was high (31.6%) for benchmark 1 but decreased to 3.6% as the definition of severe infection was extended to include WEC>2000 on the test day or 3 or 7 days later. Sensitivity (92.0%), specificity (94.2%) and predictive value of a negative test result (87.5%) were also high for benchmark 3. By detection of blood in faeces during heavy H. contortus infections prior to the emergence of high WECs, the test provided an early indication of imminent haemonchosis. Positive FOB test results are also likely to arise from other causes of blood in faeces such as fascioliasis, coccidiosis and some bacterial enteritides. Further field studies are needed to validate the method as a diagnostic test for determining the severity of H. contortus infections under diverse environmental and sheep husbandry conditions.

Objecthood, Agency and Mutualism in Valenced Farm Animal Environments.

Genetic selection of farm animals for productivity, and intensification of farming practices have yielded substantial improvements in efficiency; however, the capacity of animals to cope with environmental challenges has diminished. Understanding how the animal and environment interact is central to efforts to improve the health, fitness, and welfare of animals through breeding and management strategies. The review examines aspects of the environment that are sensed by the animal. The predictive brain model of sensory perception and motor action (the Bayesian brain model) and its recent extension to account for anticipatory, predictive control of physiological activities is described. Afferent sensory input from the immune system, and induction of predictive immune functions by the efferent nervous system are also in accord with the Bayesian brain model. In this model, expected sensory input (from external, physiological and immunological environments) is reconciled with actual sensory input through behavioural, physiological and immune actions, and through updating future expectations. Sustained discrepancy between expected and actual sensory inputs occurs when environmental encounters cannot be predicted and controlled resulting in stress and negative affective states. Through these processes, from the animal's perspective, aspects of the environment acquire a negative or positive character: that is the environment becomes valenced. In a homeostatic manner, affective experience guides the animal towards synchronisation and a greater degree of mutualism with its environment. A better understanding of the dynamic among environmental valence, animal affect and mutualism may provide a better understanding of genetic and phenotypic links between temperament, immune function, metabolic performance, affective state, and resilience in farm animals, and provide further opportunities to improve their welfare.

A Framework to Assess the Impact of New Animal Management Technologies on Welfare: A Case Study of Virtual Fencing.

To be ethically acceptable, new husbandry technologies and livestock management systems must maintain or improve animal welfare. To achieve this goal, the design and implementation of new technologies need to harness and complement the learning abilities of animals. Here, from literature on the cognitive activation theory of stress (CATS), we develop a framework to assess welfare outcomes in terms of the animal's affective state and its learned ability to predict and control engagement with the environment, including, for example, new technologies. In CATS, animals' perception of their situation occurs through cognitive evaluation of predictability and controllability (P/C) that influence learning and stress responses. Stress responses result when animals are not able to predict or control both positive and negative events. A case study of virtual fencing involving avoidance learning is described. Successful learning occurs when the animal perceives cues to be predictable (audio warning always precedes a shock) and controllable (operant response to the audio cue prevents receiving the shock) and an acceptable welfare outcome ensues. However, if animals are unable to learn the association between the audio and shock cues, the situation retains low P/C leading to states of helplessness or hopelessness, with serious implications for animal welfare. We propose a framework for determining welfare outcomes and highlight examples of how animals' cognitive evaluation of their environment and their ability to learn relates to stress responses. New technologies or systems should ensure that predictability and controllability are not at low levels and that operant tasks align with learning abilities to provide optimal animal welfare outcomes.

Attention Bias Test Differentiates Anxiety and Depression in Sheep.

Negative affective states such as anxiety and depression pose a risk to animal welfare, however, practical tests for assessing these states in animals are limited. In humans, anxious individuals are shown to pay more attention toward threatening information than non-anxious individuals, known as an attention bias. Previously, an attention bias test was developed and validated as a measure of anxious states in sheep, where more anxious sheep showed increased attention toward a threat (dog) and were more vigilant than Control animals. Studies in humans suggest that attention biases also occur in depressed individuals, with observations of attention biases toward threats, as well as biases away from positive stimuli. Given these findings, we hypothesized that an attention bias test for sheep could also be used to assess states of depression. We predicted that Merino ewes in pharmacologically induced Depressed (para-chlorophenylalanine) and Anxious (m-chlorophenylpiperazine) states would show greater attention toward a threat than Control animals (saline), but that the Depressed sheep would show relatively less interest in a positive stimulus (photograph of a conspecific). During testing, Depressed sheep paid more attention toward the threat and less toward the photograph than Control animals as predicted (Analyses of Variance, P < 0.05, n = 16 per treatment). Interestingly, Anxious sheep showed an attention bias in the opposite direction, paying more attention toward the photograph and less toward the threat than Control animals (P < 0.05). Both Anxious and Depressed sheep were more vigilant than Control animals (P = 0.002). These results suggest the attention bias test can be used to measure and differentiate states of depression and anxiety in livestock. The bidirectional nature of the attention bias identified between treatments highlights the importance of measuring multiple behaviors in the test and considering the context in which the test is applied. This will enable a clearer characterization of the affective state of an animal, as an aspect of its welfare.

A Novel Protocol to Assess Acclimation Rate in Bos taurus Heifers during Yard Weaning.

The speed with which animals acclimate to a new environment could be an important measure of ability to cope with management induced stress. This study developed a measure of acclimation rate in a group of 50 Bos taurus heifers during yard weaning over nine days. We recorded the time and order in which heifers moved through a novel funnel structure into a feeding yard daily. We hypothesised that addition of an obstacle at the entrance would increase the time it took heifers to move through the funnel, but that they would acclimate to the obstacle over a three-day period. The change in latency to move through could then be used as a measure of acclimation rate. We hypothesised that individuals which acclimated to obstacles at a faster rate might display favourable temperament as assessed by flight time. All heifers took longer to move through the funnel after a novel object was introduced, then latency decreased over the following two days while the object was present. This indicates the protocol could be useful for measuring acclimation rate at a group level. Individual acclimation rate variables, measured as change in times and orders of heifers between test days, did not appear to have any consistent relationships with flight time or weight change during or post-weaning (p > 0.05). We concluded that the protocol was inappropriate for assessing acclimation rate at an individual level, due to social effects while testing heifers as a group. Heifers which were consistently one of the first 20 to move through the funnel had a significantly greater average weight 5 and 10 months post-weaning (345 ± 9 kg and 518 ± 10 kg respectively) than heifers which were consistently one of the last 20 through the funnel (311 ± 8 kg and 484 ± 8 kg respectively; p < 0.001). This may indicate order of movement through the funnel was related to feeding motivation or another aspect of temperament not reflected by flight time.