Genetic Improvement of Lamb Survival in the Australian Merino: Behavioural and Physiological Indicators of Maternal Ability

Poor lamb survival in the Australian Merino has been recognised as a problem since the late 1950's. From the numerous studies cited in the literature, starvation is ultimately the cause of most lamb deaths but there may also be many intermediate effects involved. These may include dystocia, ewe/lamb interactions, climate and nutrition. While dystocia and starvation appear to be distinct causes of lamb deaths, sub-lethal birth trauma may result in the animal dying of starvation through low vigour or simply an incapacity to follow its mother. Two methods of overcoming the problem of lamb mortality are management and genetic selection. Management has met with limited success and incurs an annual cost. Improvements obtained through breeding however are permanent. The major thrust of the study reported here deals with identifying behavioural and physiological indicators of maternal ability using two flocks that have been shown to differ genetically in their capacity to rear lambs. The first of these flocks was the Trangie Fertility Flock, the ewes of which have a superior capacity to rear their lambs than those of the second flock, the Trangie Random Flock. The differences between these two flocks were arrived at by genetic selection

Self-administration by consumption of flunixin in feed alleviates the pain and inflammation associated with castration and tail docking of lambs

It can be impractical for farmers to provide pain relief to livestock following husbandry procedures such as castration and tail-docking, particularly in pasture-based systems because animals need to be repeatedly gathered to handling facilities and restrained. We investigated whether voluntary consumption by lambs of an analgesic incorporated into feed can achieve pain relief following surgical castration and hot-knife tail-docking. Sixty-four, singleton, male Merino lambs were randomly allocated to one of four treatment groups: sham castration and tail-docking (S), castrated + tail-docked + no pain relief (C), castrated + tail-docked + flunixin in feed (4.0 mg/kg, CF) and castrated + tail-docked + flunixin injection (2 mg/kg, CI). Haematology, cortisol, and plasma haptoglobin concentrations were measured before and up to 48 h after treatment. Lambs also had their scrotal and tail wounds scored based on severity of swelling and wound appearance, with 2 being a healed wound and 8 being severe swelling and evident necrosis and pus. Behaviours were recorded by video for 12 h after treatment. Lambs in the CF and CI groups displayed fewer active pain avoidance behaviours (P < 0.05, mean = 3.06 and 3.75 respectively) than C lambs (mean = 6.06) in the first hour following treatment. CF and CI lambs also displayed fewer pain related postures in the 12 h following treatments. All lambs that were castrated and tail-docked had an increase in cortisol 30 min after treatment (df = 57, P < 0.05 for all). The CI group had lower cortisol concentrations by 6 h (t = 2.17, 25.02 nmol/L) and CF by 12 h (t = 1.76, 33.44 nmol/L) compared with C lambs, however these concentrations were still above basal levels. Flunixin treatment also reduced inflammation, with CF and CI lambs having lower neutrophil/lymphocyte ratios and lower mean wound scores than C lambs. Provision of flunixin in feed was as effective as the flunixin injection in improving behaviour and reducing inflammation in lambs following castration and tail-docking

Validating attention bias as a novel measure of affect in sheep

To facilitate the understanding and enhancement of animal well-being in livestock production systems, there is a need to develop robust methods which can assess the emotional or affective states of animals, as an aspect of their welfare. Chapter 1 of this thesis discusses some current methods used for the assessment of animal affect, highlighting the key limitations of each approach. The potential role of cognitive methods for welfare assessment is introduced, with a particular focus on attention bias tests. The aim of this thesis was to further develop and validate a novel attention bias test for the assessment of affective states in sheep. Chapter 2 examines the impact of pharmacologically-induced stress on judgement bias and attention bias in sheep. The study finds no clear indication that elevated cortisol concentrations impacted on cognitive biases in sheep. Chapter 3 refines the attention bias test methodology to remove a habituation period, improving the practical application of the test. The study demonstrates that pharmacologically-induced anxiety-like and calm-like states impact on attention bias in sheep. Chapter 4 introduces a modified method for the assessment of attention bias, which is shown to assess and differentiate pharmacologically-induced anxiety-like and depression-like states in sheep. Chapter 5 examines the potential influence of pharmacologically induced positive affective states on the modified attention bias test, finding no clear effect of positive states on attention bias in sheep. It is suggested that external factors may have confounded results of this study. Chapter 6 examines repeatability of the attention bias test to gain insight into the factors influencing animal behaviour during the attention bias test. Key measures of attention had low repeatability and are suggested to be readily influenced by emotions and moods. Measures of vigilance and zones crossed had moderate repeatability and are suggested to be more heavily influenced by temperament or personality traits. Finally, chapter 7 concludes that the attention bias test developed throughout this thesis may be a useful and practical tool for the assessment of negative affective states in sheep

Bayesian change-point analysis of grazing sheep behaviour to identify lambing

The main aim in analysing data for animal movement is to reveal behavioural mechanisms by which the animal utilises complex and variable environments. Movement data also reflects behaviours that are heterogeneous. Statistical analysis of multidimensional, auto-correlated and irregular interval movement data is difficult. Animal tracking devices such as collars with global positioning system (GPS) capabilities enable continuous and automatic tracking of an animal's position and the value of suck spatial-temporal information is improved if the corresponding activity of the animal is known. GPS animal tracking devices (collars) were used in the spring (Sep-Nov) of 2008 and 2009 to monitor movement of 20 pregnant grazing fine wool Merino ewes. Mean daily velocities (m/s) were calculated for three time periods within a day: 0500-1100h, 1200-1800h and 1900-0400h and subjected to Bayesian change-point analysis (BCP) in an attempt to identify when a change in behaviour (reduction in velocity) occurred and if this was associated with lambing. The approximate day of lambing, within 48h, was known to have occurred between 16 and 29d into the data collection period for both years. In 2009, 5 ewes were closely monitored for lambing date and BCP successfully identified a change-point that could be associated with lambing in the majority of ewes monitored. This method was then applied to movement data collected in 2008 to identify lambing for that season. Based on the analysis, the time period 0500-1100h appeared to be the best in which to determining lambing using BCP. Posterior probabilities and means calculated using BCP appears to be a useful and robust methodology that could be incorporated into decision support tools for farmers to help in decision making based on movement data from GPS collars

The effect of flock size and paddock complexity on following behaviour in Merino sheep

Little is known about the impact of flock size on the social structures (leadership and sub-grouping) of the highly gregarious Merino sheep. As part of a larger experiment examining the capacity to manipulate flocks using 3 leaders trained to approach a stimulus for a lupin grain food reward, the present experiment examined the impact of flock size on responsiveness to leader-initiated naïve (non-trained) group movement and sub-grouping formation in small paddocks (2 ha). Two groups SM (Small Mob, n=18, 3 trained + 15 naive) and LM (Large Mob, n=48, 3 trained + 45 naive) were tested during Morning Grazing and Afternoon Grazing in 3 open paddocks (OPs) and 3 complex paddocks (CPs). In all 6 tests 100% of the SM followed leader initiated movement approaching within 6m of the stimulus in OPs and CPs. The number of LM group members following changed significantly with more sheep following in the OPs than the CPs (Chi-square(df3)=6.39, P=0.012). The gregarious nature of sheep, their social cohesiveness and allelomimetic behaviour seemed to facilitate group movement. Passive recruitment by leaders and associated following behaviour of naive sheep was observed consistently in the OPs but in the LM group complexity did reduce the influence of leaders. Overall sub-grouping did not change (Chi-square (df3)=0.26, P=0.97) with group size and did not significantly alter response to leaders in the CPs or OPs. Sub-grouping in both the SM and LM CPs increased by three additional sub-groups in the afternoon compared with the morning. This may be a reflection of high pasture availability for morning grazing subsequently reducing emphasis on food gathering in the afternoon i.e.: social interactions rather than hunger needs became predominant. It seems that in small complex paddocks sub-grouping may be related more to level of social activity than to group size or paddock complexity per-se

Beyond the Miracle Foal: A Study into the Persistent Effects of Gestational Immaturity in Horses

Breeding horses can be a financially and emotionally expensive undertaking, particularly when a foal is born prematurely, or full term but dysmature, showing signs normally associated with prematurity. In humans, a syndrome of gestational immaturity is now emerging, with associated long-term sequelae, including metabolic syndrome, growth abnormalities and behavioural problems. If a similar syndrome exists in the equine and can be characterised, opportunities for early identification of at-risk individuals emerge, and early intervention strategies can be developed. This thesis explores the persistent effects of gestational immaturity manifest as adrenocortical, orthopaedic and behavioural adaptation in the horse.&#13; Basal diurnal cortisol levels do not differ from healthy, term controls, but when subjected to a low dose ACTH challenge, gestationally immature horses presented a depressed or elevated salivary cortisol response, suggesting bilateral adaptation of the adrenocortical response. This may be reflected in behavioural reactivity, but the outcomes from a startle test were inconclusive. A survey of horse owners indicated that gestationally immature horses tended to be more aggressive and active than controls, aggression being displayed mostly in families of Arabian horses. Case horses also tended to be more active, intolerant, and untrusting. Gestationally immature horses have restricted growth distal to the carpal and tarsal joints, and this results in a more ‘rectangular’ conformation in adulthood compared to controls. They also often present with angular limb deformities that adversely affect lying behaviour and recumbent rest. This, however, can be mitigated using analgesic therapy, suggesting chronic discomfort.&#13; Based on these findings, it is reasonable to postulate that a syndrome of gestational immaturity may persist, both clinically and sub-clinically, in affected adult horses. Further work is required to fully characterise this syndrome and validate the outcomes in larger populations, thereby providing a foundation for interventions applicable in the equine breeding industry

Stakeholder Perceptions of Welfare Issues and Indicators for Extensively Managed Sheep in Australia

An online survey was designed to form the basis of a framework for the welfare assessment of extensively managed sheep in Australia. The survey focused on welfare compromise and useful welfare indicators. A total of 952 people completed the survey in its entirety, representing four stakeholder groups: Public (53.6%), Producer (27.4%), Scientist (9.9%), and Service provider (9.1%). Animal welfare was considered to be important by all participating groups in this survey (average score of 3.78/4). Respondents felt the welfare of grazing sheep was generally adequate but improvement was desired (2.98/5), with female members of the public rating sheep welfare significantly worse than other respondents (p &lt; 0.05). Environmental issues were considered to pose the greatest risk to welfare (3.87/5), followed by heat stress (3.79), lameness (3.57) and husbandry practices (3.37). Key indicators recognised by all respondents were those associated with pain and fear (3.98/5), nutrition (4.23), mortality/management (4.27), food on offer (4.41) and number of illness/injures in a flock (4.33). There were gender and stakeholder differences in the perceived importance of both welfare issues and indicators with women and the public consistently rating issues (all p &lt; 0.01) and indicators (all p &lt; 0.05) to be of greater significance than other respondents. These results highlight the importance of including all stakeholders and an even balance of genders when developing a welfare framework that can address both practical and societal concerns

Using Radio-Frequency Identification Technology to Measure Synchronised Ranging of Free-Range Laying Hens

Free-range laying hen systems provide individuals a choice between indoor and outdoor areas where range use may be socially influenced. This study used radio-frequency identification technology to track the ranging of individually-tagged hens housed in six experimental free-range pens from 28 to 38 weeks of age (46&#8315;50 hens/pen). All daily visits to the range were used to study group behaviour. Results showed that 67.6% (SD = 5.0%) of all hen movements through the pop-holes outdoors or indoors were following the movement of another hen (&#8216;pop-hole-following&#8217;) compared to only 50.5% of movements in simulated random data. The percentage overlap in time that all combinations of hen pairs within each pen spent simultaneously outdoors or indoors showed a median value of overlap greater than the 90th percentile of random data. Pens housing hens that had been provided variable enrichments from 4 to 21 days (n = 3 pens) showed higher &#8216;pop-hole-following&#8217; behaviour and a higher percentage of hen-pair association compared to hens reared in non-enriched conditions (n = 3 pens). These results show that birds in each free-range pen were primarily a cohesive flock and early enrichment improved this social cohesiveness. These results have implications for understanding free-range flock-level behaviour

Prematurity and Dysmaturity Are Associated With Reduced Height and Shorter Distal Limb Length in Horses

The long-term effects of gestational immaturity in the premature (defined as height at the withers), from those that are more square (body length = height at the withers). Varimax rotation of PC1 and analysis of different gestational groups showed a significant effect of gestational immaturity (P = .001), with the premature group being more affected than the dysmature group (P = .009, P = .012). Mean values for the four dominant indices showed that these groups have significantly lower distal limb to body length relationships than controls. The observed differences suggest that gestational immaturity may affect anatomical ratios at maturity, which, in combination with orthopedic issues arising from incomplete ossification, may have a further impact on long-term athletic potential