Scottish Animal Welfare Commission: welfare of isolated populations of feral animals - report

Appendix VI – Five Domains welfare model as applied to different scenarios for sheep on St Kilda

Baseline scenario (no change to current state)

1) Domain 1 - Nutrition / hydration

Examples of Compromises

• Restricted food availability (seasonally)
• Possibly also poor-quality food

Examples of Enhancements

• Natural feed sources when available
• Opportunity for nutritional diversity
• Opportunity for choice and expression of dietary preference/diet selection
• Variety of water sources available

2) Domain 2 - Physical environment

Examples of Compromises

• Rough/rocky terrain may lead to injuries

Examples of Enhancements

• Buildings/man-made structures can provide some shelter
• Opportunity for exploration and investigation, environmental diversity
• Opportunity got agency and autonomy in location selection

3) Domain 3 – Health

Examples of Compromises

• Weakness due to loss of appropriate nutrition/lack of food (seasonally)
• Poor nutrition affects disease resistance / parasitism / recovery from injury / reproduction
• High rates of endoparasitic infection
• Lack of vaccination against disease
• Lack of timely treatment for injury or disease or euthanasia if required

Examples of Enhancements

• No natural predators
• Increased resilience to parasites
• No pain caused by anthropogenic management actions (e.g. castration)

4) Domain 4 - Behavioural interactions

Examples of Compromises

• Increased competition for limited resources
• Disruption of hierarchies if individuals die
• Loss of positive interactions if individuals die or are in extremis

Examples of Enhancements

• Able to explore environment and participate in new social bonding
• Physical and social environment allows sheep to engage in species-typical foraging/reproductive and other social interactions
• Opportunities to maintain affiliative social interactions (social contacts, maternal care)
• Opportunity to express mate choice
• Natural weaning and prolonged female-female social contact
• Limited anthropogenic disturbance

5) Domain 5 - Mental state

Examples of Compromises

• Hunger, anxiety, fear due to lack of food
• Weakness/exhaustion
• Negative emotional states associated with starvation/death
• Frustration from inability to perform social behaviours when weak

Examples of Enhancements

• Positive emotional states from life in a natural environment
• Social interactions
• Sense of control / security
• Opportunity for agency and autonomy
• Ability to experience/develop competence and overcome challenge

Support for existing sheep: Provision of nutritional support

Here we consider the compromises and enhancements that change relative to the baseline scenario by this action.

Domain 1 - Nutrition / hydration

Examples of Compromises

• Not all animals may be able to access supplementary feed e.g. easier to provide in village bay area (which already has better nutrition)
• Increased nutrition of sheep will lead to increase survival and reproduction, (the benefits of feeding may be short term if other steps are not also taken to manage the population)

Examples of Enhancements

• Improved food quality / access to sufficient food of a suitable quality (short period)
• Increased food choice

Domain 2 - Physical environment

Examples of Compromises

• —

Examples of Enhancements

• —

Domain 3 – Health

Examples of Compromises

• Health benefits may be short-lived as increased survival and reproduction will lead to increased competition.
• Possible increase in population instability which may make future crash years more rather than less likely
• Risks of injury from food competition or disrupted social hierarchy/home ranging

Examples of Enhancements

• Possibility to have better physical fitness
• Veterinary intervention if sick animals seen
• Absence/reduction of disease, parasites or injury
• Better resistance to parasites
• Improved survival in the short term (unless steps also taken to manage population)

Domain 4 - Behavioural interactions

Examples of Compromises

• Some anthropogenic disturbance
• Some additional competition for new food resources provided
• Skew population dynamics as food could only be provided in some areas
• Alteration in social contacts and home ranging if food only supplied in some (accessible) areas

Examples of Enhancements

• More prolonged mother-offspring interactions in better fed ewes

Domain 5 - Mental state

Examples of Compromises

• Fear and frustration from increased food competition
• Pain from fighting and injury

Examples of Enhancements

• Gastrointestinal comfort/satiety

Support for existing sheep: Provision of health treatments

Options here include the provision of anthelminthics and vaccinations. These are likely to need to be repeated on a regular basis to be efficacious.

Domain 1 - Nutrition / hydration

Examples of Compromises

• Possibly more sheep will survive and compete for same food resources

Examples of Enhancements

• Improved food utilization if e.g. parasitic worms controlled

Domain 2 - Physical environment

Examples of Compromises

• Increased population could mean more competition for shelter

Examples of Enhancements

• —

Domain 3 – Health

Examples of Compromises

• Possible injuries resulting from rounding up sheep for treatment
• Need to ear tag sheep to record treatments
• Short term benefits likely to then lead to same level of sheep mortality and may increase population instability
• Impacts on worm population resistance if only some sheep can be treated
• Reduction in overall fitness in some sheep if natural resilience/resistance is disrupted

Examples of Enhancements

• Possibility to have better physical fitness
• Veterinary intervention for other conditions possible
• Absence/reduction of disease, parasites or injury
• Better resistance to parasites (in some sheep)

Domain 4 - Behavioural interactions

Examples of Compromises

• Some anthropogenic disturbance to allow treatments
• May lead to disruption of social bonding by gathering sheep, possible increased lamb or juvenile losses
• Some competition for additional food resources/other resources if more sheep survive

Examples of Enhancements

• —

Domain 5 - Mental state

Examples of Compromises

• Fear, panic, pain and anxiety from anthropogenic disturbance

Examples of Enhancements

• Gastrointestinal comfort
• Reduced pain or malaise from some conditions

Support for existing sheep: reproductive management

This includes either physical castration of males or some form of pharmacological manipulation of fertility for males or females.

Domain 1 - Nutrition / hydration

Examples of Compromises

• —

Examples of Enhancements

• Natural feed sources when available for fewer sheep

Domain 2 - Physical environment

Examples of Compromises

• —

Examples of Enhancements

• —

Domain 3 – Health

Examples of Compromises

• Possible injuries resulting from rounding up sheep for treatment
• Risk of capture myopathy due to stress of gathering and handling
• Need to ear tag / identify sheep to record treatments
• Depending on treatment short or longer term pain associated with the intervention
• Except for physical castration of males these will need to be repeated interventions to ensure sterility – hard to ensure the same animals can be reliably captured and treated

Examples of Enhancements

• Possibility to have good physical fitness through improved nutrition
• Veterinary intervention possible

Domain 4 - Behavioural interactions

Examples of Compromises

• Some anthropogenic disturbance to allow treatments
• Lack of reproductive opportunities for some/all sheep
• Inability to express positive aspects of social interactions such as courtship and maternal care

Examples of Enhancements

• Less competition for food resources

Domain 5 - Mental state

Examples of Compromises

• Fear, panic and risk of injury during gathering and handling sheep
• Pain associated with treatments (short or longer term depending on the intervention)
• Fewer opportunities for positive/affiliative social encounters

Examples of Enhancements

• —

Population reduction: Annual culling of a proportion of the flock

Domain 1 - Nutrition / hydration

Examples of Compromises

• Unless culling carried out annually benefits are likely to be short term and may result in more competition if the population increases rapidly

Examples of Enhancements

• Natural feed sources when available for fewer sheep

Domain 2 - Physical environment

Examples of Compromises

• Rocky or uneven terrain may be a source of injury during gathering

Examples of Enhancements

• —

Domain 3 – Health

Examples of Compromises

• Possible injuries when escaping the cull or due to miss-shots – could lead to very severe welfare impacts if animals cannot then be located and treated.
• Risk of capture myopathy due to stress of gathering and handling
• Culling some animals may disrupt population fitness which could lead to worse health outcomes in the future

Examples of Enhancements

• Possibility to have good physical fitness in sheep that are not culled
• Absence/reduction of disease, parasites or injury if survive cull and more resources are available
• Better resistance to parasites if survive cull and more resources are available

Domain 4 - Behavioural interactions

Examples of Compromises

• Human disturbance including handling during the culling process
• Loss of social/family networks
• Disruption of complex hierarchies and possible movements of home ranges

Examples of Enhancements

• —

Domain 5 - Mental state

Examples of Compromises

• Fear, panic and significant risk of injury/death during intervention as animals flee
• Risk of mis-shots and leaving injured animals experiencing severe pain
• Frustration, anxiety, grief through the loss of important individuals

Examples of Enhancements

• Positive emotional states due to satiety if more food resources are available to fewer sheep

Population reduction: Annual trapping for removal of a proportion of the flock to the mainland

NB this analysis refers only to those animals that are not removed from St Kilda. The welfare of those animals removed will be influenced by the method of removal and the habitat to which the animals are relocated. Some of these issues are considered in the next scenario.

Domain 1 - Nutrition / hydration

Examples of Compromises

• —

Examples of Enhancements

• Natural feed sources when available for fewer sheep

Domain 2 - Physical environment

Examples of Compromises

• Rough/rocky terrain may lead to injuries, especially during the trapping process as animals attempt to evade capture

Examples of Enhancements

• —

Domain 3 – Health

Examples of Compromises

• Possible injuries when escaping the gathering and handling – could lead to very severe welfare impacts if animals cannot then be located and treated.
• Risk of capture myopathy due to stress of gathering and handling
• Removing some animals may disrupt population fitness which could lead to worse health outcomes in the future

Examples of Enhancements

• Possibility to have good physical fitness from improved resources for fewer sheep
• Absence/reduction of disease, parasites or injury in animals with more access to resources

Domain 4 - Behavioural interactions

Examples of Compromises

• Human disturbance including handling during the trapping process
• Loss of social/family networks
• Disruption of complex hierarchies and social dynamics/cultural knowledge, home range fidelity

Examples of Enhancements

• —

Domain 5 - Mental state

Examples of Compromises

• Fear, panic and significant risk of injury/death during intervention as animals flee
• Anxiety, frustration and fear through loss of important social contacts (e.g. mother-offspring)
• Pain from possible injuries incurred during the gathering/trapping phase and from increased risk of fighting due to social disruption

Examples of Enhancements

• Positive emotional states due to satiety if more food resources are available to fewer sheep

Complete removal: Removal all the flock to a managed system on the mainland

Domain 1 - Nutrition / hydration

Examples of Compromises

• Short term food and water restriction during removal
• Exposure to new foods that may not be palatable or preferred by sheep
• Possible loss of food choice and ability to express preferences

Examples of Enhancements

• Improved food quality / provision may be possible in new location

Domain 2 - Physical environment

Examples of Compromises

• Possibly restricted/less heterogeneous habitat in new location, may also mean less space, less choice, less opportunity for agency depending on the location
• Short term confinement and likely exposure to unpleasant noise, odour, lack of comfortable bedding etc during removal
• Risks posed by the transportation environment and sensory overload

Examples of Enhancements

• Possible presence of desirable environmental features in new location (assuming these would be better than their current provision)

Domain 3 – Health

Examples of Compromises

• Short-term risk of injury and death due to capture and relocation process
• Risk of capture myopathy from stress associated with the capture and removal process.
• Exposure to new pathogens in the environment for which the sheep may have no natural immunity

Examples of Enhancements

• Possibility to have good physical fitness if new environment allows improved access to food
• Ability to provide improved veterinary care such as vaccination, parasiticides, euthanasia etc

Domain 4 - Behavioural interactions

Examples of Compromises

• Anthropogenic disturbance and ongoing presence
• Possible disruption of hierarchies and family networks when individuals removed
• Competing for resources in a novel environment

Examples of Enhancements

• Reduced competition with conspecifics for feed resources may be possible

Domain 5 - Mental state

Examples of Compromises

• Fear, panic and significant risk of injury/death during intervention as animals flee during capture and transport process
• Anxiety, frustration and fear through loss of important social contacts (e.g. mother-offspring) that may be temporarily or permanently disrupted
• Pain from possible injuries incurred during the gathering/removal phase and from increased risk of fighting due to social disruption
• Possible prolonged or permanent increase in fear due to close human interactions during removal and in new location
• Lack of control as a result of social disruption

Examples of Enhancements

• Gastrointestinal comfort from improved nutrition and health

Complete removal: Culling of all the flock

Here we assume the only feasible approach would be stalking and shooting of all the sheep, possibly over a prolonged period of time.

Domain 1 - Nutrition / hydration

Examples of Compromises

• —

Examples of Enhancements

• —

Domain 2 - Physical environment

Examples of Compromises

• —

Examples of Enhancements

• —

Domain 3 – Health

Examples of Compromises

• Short-term risk of injury due to escape attempts in hazardous terrain and miss-shots

Examples of Enhancements

• —

Domain 4 - Behavioural interactions

Examples of Compromises

• —

Examples of Enhancements

• —

Domain 5 - Mental state

Examples of Compromises

• Depending on one’s ethical perspective, loss of future life experiences
• Fear, panic and significant risk of injury/death during intervention as animals flee
• Risk of mis-shots and leaving injured animals experiencing severe pain
• Short-term fear, frustration, anxiety and loss from removal of important individuals.

Examples of Enhancements

• —