Behavior Physiology & Mechanisms Flashcards
Do animals feel pain?
- Comparative anatomy / physiology / behavior to humans.
- 75% to 95% of university staff, faculty, students at one American vet school believe that animals experience pain like humans.
What are the benchmarks for dx’ing pain?
- If it cause pain in humans.
- If it changes normal behavior.
What is the pain pathway?
Receptors
-skin, muscle, bone, joint, viscera.
Transmission
- peripheral nerves.
- dorsal horn of spinal cord.
Perception
-cortex.
What is windup in the pain pathway?
Takes less stimulus to cause the same amount of pain.
- Increased sensitization of the pain pathways in response to sustained input.
- Pathophysiology not clearly determined.
- Increased dose of analgesics needed.
How can windup be prevented?
Give anaglesics prior to induction of painful stimuli.
What can pain cause?
- Catabolism: break down body system.
- Impaired respiration (very important).
- Delay wound healing.
- Prolong hospitial stays.
- Increase in morbidity and mortality.
What happed to rats given morhphine post op for mammary adenocarcinoma?
They had a rate of mets 70% less than rats not given morphine.
AVMA Postion on Pain I
Animal pain and suffering are?
Clinically important conditions that adversly affect an animal’s quality of life.
AVMA Postion on Pain II
Drugs, techniques, or husbandry methods used to prevent and control pain must be?
-Tailored to individual animals.
Should be based on:
- Species
- Breed
- Age
- Procedure Performed
- Degree of Tissue Trauma
- Individual Behavior Characteristics
- Degree of Pain
- Health Status
Behavior Indicators
The “Normal” Animal
- Alertness
- Curiosity
- Eating
- Drinking
- Interaction with Others
- Play
- Broad Range of Activities
We need to be familiar with the normal animal in order to?
- Identify deviations from normal that may show that an animal’s welfare is poor and/or that it is showing signs of disease.
- Notice positive indication of well being (not just suffering).
- Identify signs that animals have been well treated or badly treated by humans.
What are the response to pain?
-Modify behavior through learning in order to minimize recurrance.
\*Avoidance Behavior
-Try to minimize pain and assist healing.
\*Immobility, Licking, Distance from Conspecifics
-Exhibit automatic responses to protect part or all of body.
\*Withdrawal reflex if approached.
-Elicit help or try to stop another animal from inflicting more pain.
\*Aggression
Acute Signs of Pain
- Increase or decrease in physical activity.
- Tearing, changes in eye expression, fixed and dilated pupils.
- Change in appetite.
- Change in personality.
- Anxiety
- Agression
- Self mutilization.
- Vocalization.
- Salivation.
- Tachypena / Tachycardia.
- Trembling
- most likely pain or scared, not always temperature.
NOTE: if a bird is in pain they may just try to fly away before they can issue the pain behavior.
Chronic Signs of Pain
- Guarding behavior in movement and posture.
- Avoidance of pain aggrivating infulences.
- Seeking of pain relieving factors and envvironments.
- Self care of painful region.
- Stress
- Weight loss.
- Inappetance
- Sleep disturbances.
Measurement of Pain
- Hard to do subjectively in animals.
- No good guidelines available.
- No perfect biological markers.
- Anthropomorphism is applicable since nervous systems of mammals are similar across species.
Pros and Cons of Measurement Techniques
The advantages and disadvatages of the different techniques used to measure a variety of welfare-related physiological parameters will be discussed in terms of how invasive, restrictive, and disturbing they are.
- Invasivness refers to the severity of implantation when a measuring device has to be implanted into a part of the body.
- Injection, Implantation, Observation
- Restriction refers to the degree to which the animals need to be restrained to allow sampling.
- Is restraint required?
- Disturbance refers to the degree to which sampling itself is likely to disturb the parameter being measured.
- Effect of sampling on parameter.
Pros of Behavior as a Pain Indicator
- Invasiveness
- Visual observation
- Restriction
- No restraint required
- Disturbance
- No effect on behavior
- Timing
- Changes are immediate
Cons of Behavior as a Pain Indicator
- Subtle changes missed easily.
- Must know normal behavior for species.
- Prey species hide pain to decrease predation.
- Much intra-observer variability.
- Age and previous experience may vary responses.
- Sensitivity can vary.
- males require more analgesics than femals.
- anxious individuals need more analgesics than calm individuals.
- Position in hiearchy can cause variation in response.
Three Welfare Definitions
- Feelings: mental status
- Functioning: physical status
- Nature of the Species: telos
These three welfare concepts can be translated into three broad definitions of welfare. Scientists working on animal welfare tend to relfect their own views on which aspect is important in their definition of welfare.
Welfare: Feelings
- “…neither health nor lack of stress nor fitness is necessary and/or sufficient to conclude that an animal has good welfare. Welfare is dependant upon what animals feel.” (Duncan, 1993)
- “The question is not, can they reason? Nor, can they talk? But, can they suffer?” (Bentham, 1789)
How does the animal feel about it?
Welfare: How to Assess Feelings
- Preferences
- Strength of preferences.
- Assume animal will work harder for things they want.
- Lack of abnormal behaviors.
- Vocal signals.
- Other communication signals.
- These are subjective, open to interpretation and misinterpretation.
Welfare: Functioning
- “Welfare defines the state of an animal as regards its attempts to cope with its environment.” (Fraser & Broom, 1990)
- “I suggest that an animal is in a poor state of welfare only when physiological systems are disturbed to the point that survival or reproduction are impaired.” (McGlone, 1993)
Fraser and Broom refer to how an animal copes with its environment. Coping is essentially a reflection of the physical condition of the animal.
McGlone seems to have a more extreme view that welfare is only poor when survival or reproduction are impaired by a physical problem.
- “..the only defensible measurement of well-being in animals is to determine if the animal is suffering from stress. Furthermore, I believe that the most appropriate indicator of stress is the appearance of a pre-pathological state.” (Moberg, 1985)
Welfare: How to Assess Functioning
- Growth Rate
- Reproductive Success
- Longevity
- Injury
- Disease
- Objective measures but not conclusive of good welfare.
Objective measures cannot be argued and therefore some can not argue with the welfare of the animal if these measures remain the same.
Welfare: Nature of the Species
- “Not only will welfare mean control of pain and suffering. It will also entail nuturing and fulfillment of the animals’ nature, which I call telos.” (Rollin, 1993)
- Suggests that to promote welfare, need to raise animals so they can behave in “natural ways”.
Rollin recognizes that mental states (pain and suffering) are relevant but that fulfilling nature (telos) is also relevant to welfare.
- “In principle, we disapprove of a degree of confinement of an animal which necessarily frustrates most of the major activities which make up its natural behaviour..” (Brambell, 1965)
- “If we believe in evolution… in order to avoid suffering, it is necessary over a period of time for the animal to perform all the behaviours in its repertoire because it is all functional…” (Kiley-Worthington, 1989)
Welfare: How to Assess Nature of the Species
- Study behavior of animal in wild state and compare to behavior of animal in captivity.
- Behavior repertoire may include activites that decrease welfare.
- Predation
- Aggression
Even though something is seen in the wild, it doesn’t mean they have a bad welfare.
Relationship Between the Three Welfares
Whatever definition is used, there is an undeniable link between all three concepts. Any significant compromise in one aspect tends to affect the other two.
It is therefore reasonable to take a hollistic approach and consider all three elements.
Discuss the feelings, functioning, and welfare implications of an animal in a local farming system.
- Matitis and Laminitis are the most common on a dairy farm.
- Cows cannot naturally breed, raise young.
- Calves are usually hiders.
- All farming systesm restrict normal behavior to some extent.
Examples:
- Fences and housing restrict normal ranging behavior.
- Controlled breeding restricts normal sexual behavior.
The Five Freedoms Scale
The Five Freedoms provide a convenient list of aspects that are considered to be important for all animals.
The diagram above shows different freedoms across a scale from poor to good. The ‘poor’ side of the spectrum signifies that the particular need has not been met – on moving towards the ‘good’ end, we can show that the need (or freedom) has been fulfilled.
An animal may have different levels of each of the five freedoms – some of the aspects may be good, while others may be poor.
Disease & Welfare
Disease is closely related to welfare. A diseased animal can have many of its Five Freedoms affected. As we see from the diagram above, disease can cause poor welfare, which in turn can contribute to disease, in a vicious cycle.
Also, an animal that has poor welfare due to a separate stressor such as chronic exhaustion is more prone to disease, as the immune system is suppressed.
What do cows require in a lying area?
- Enough space/cubicles for 90% of cows to lie down at same time
- Lie down 60% of day
- Ruminate lying down
- Farmer wants cows either milking, eating, lying down chewing cud
- To stand
- Longitudinal space: space in front to lunge
- To lie down
- Perpendicular space: move sideways when lie down
What did the following study show?
Assessing cow comfort: effects of two floor types and two tie stall designs on the behaviour of lactating dairy cows
D.B Haley, A.M de Passillé, J Rushen
Applied Animal Behaviour Science 20 February 2001 (volume 71 issue 2 Pages 105-117)
- This study assessed the time that cows spent lying in a 24 hour period on different lying surfaces in a cubicle shed. Cows provided with a soft compressible bed would lie down for about 70% of the time, which is similar to a cow grazing at pasture. However, this was reduced by a harder rubber mat or concrete.
- These harder surfaces, therefore, restrict normal behaviour. Furthermore, this restriction of lying behaviour has health implications, as increased lameness is associated with reduced lying times.
