Assessment of Welfare

Welfare

• The concept of welfare has moved away from just providing feed, water, and a clean cage.

• We are now charged with providing for the psychological wellbeing of our animals.

• Why?• Assessment?

– Behavioral tests– Biochemical analyses

Behavioral Assessment

• Behavioral signs of stress– Changes in appetite– Changes in defecation or urination– Avoidance– Immobilization– Changes in activity level– Aggression– Stereopathies

Testing ArenasWhich mouse is more fearful?

Interpreting Results• Open Field Test

– Fearful mice tend to stay close to the wall for protection.

– Bolder mice explore the middle of the arena

• Movement can be interpreted as– Escape/avoidance– Exploration– Play

Biochemical Assessment

• Biochemical measures of stress– Acute

• SAMS: Increased plasma levels of NE and Epinephrine

• HPA: Increased plasma levels of ACTH and glucocorticoids

– Chronic• WBC count

– Plasma monocytes increase; don’t migrate– Plasma neutrophils increase but impaired phagocytosis– Decrease in B and T lymphocytes

Interpreting Results

• Biochemistry varies with – Circadian Rhythm:

– Social status:

– Animal gender:

– Observer gender:

– Line or breed

T higher in dominant maleGC higher in subordinate male

NE is ♀ > ♂ & DE > E

Baseline glucocorticoids rise before 1st mealHigher at dusk in nocturnal animals Higher at dawn in diurnal animals

GC levels rise in the presence of a human male observer, but not a female observer

Biochemistry varies with Line and Sex

Example only—don’t memorize

What’s the take-home message?

Get baseline levels from the same line, sex, age, and social statusTake measurements from the same time of day and same cycle stage.

Comparative Biochemistry

Mice at 8 weeks of age Balb/cJ C57Female Male Female Male Units

WBC 3.24 2.86 3.48 2.62 103 cells/ulPercent Monocytes 0.80 0.90 0.70 1.40 %Percent Neutrophils 14.80 23.10 7.40 18.50 %B cells 53.43 51.06 56.13 57.80 %T cells 16.95 20.82 15.51 13.60 %

Information from the Jackson Laboratory website

Interpreting Results• Does NE increase more during breeding or

transport?– Breeding

• Does corticosterone increase more during movement of home cage or seeing another rat decapitated?– Movement of the home cage

• Does corticosterone increase more during the entrance of a male technician into its room or a 15-minute restraint in a plastic tube?– Levels are equal

Gender affects on Research Results

• A recent study looked at the effects of olfactory exposure to men on stress and related analgesia in rodents– Pain levels were determined using the grimace test.– It was noted that when the observer, seated ~0.5 m away,

was male, there was a significant decrease in facial grimacing relative to no observer

– This effect was not noticed with a female observer– The effect was short-lived. Within 30 minutes, the rodent

had habituated to the presence.– It is a result of “Stress-Induced Analgesia” – It calls into question studies in which a male technician

was used to determine pain or stress levels in rodents.

Stress vs Distress (Dr. Moberg)Normal Function

Altered biological function

Pre-pathological state

Pathology

Stimulus

Stimulus

Stimulus

Relief from stimulus Stress

Distress

Stress vs Distress, An ExampleNormal Function

Altered biological function

Pre-pathological state

Pathology

Stimulus

Stimulus

Stimulus

High ammonia levels

High ammonia levels

High ammonia levels

Loss of ciliated epithelium

Entry of bacteriaImmune system depression

Respiratory disease

StressSAMS

↑ NE and EpiHPA

↑ ACTH and GC

↑ Glucose levels in plasma ↑ O2 from lungs↑ circulation of glucose and O2

↑ Glucose levels in plasma

Winning male

Male mice fighting

All levels return to normal

DistressSubordinate male repeatedly attacked

Sensitization blocks negative feedback of glucocorticoids

Breakdown of fat and muscle for glucose

Body condition drops

Leukocytosis—Decreased immunityOpen to opportunistic infection

Breakpoint Stress

• Breakpoint stress—no longer able to respond or adapt to stress; no longer able to cope.

• Affected by– Severity– Predictability– Duration– Interval

The longer the stress goes on without a break for recovery, the more the body resources are depleted.

Habituation vs. sensitization

Breakpoint Stress

• Indicators– Change in weight or body condition– Change in organ weight and size

• Hypertrophy: • Hypotrophy:

– Suppressed reproduction– Gastric ulceration– Self-mutilation– Suppressed immune function disease

Adrenal gland and heartThymus gland and spleen

Individual Response

• Same conditions don’t lead to same response in all animals.

• Don’t rely on a single indicator to identify stress.

• Always get baseline levels

• Not all stress is bad.

Control of Variables• Housing

• Nutrition

• Health

• Genetics

• Cages designed for visibility, sanitation, and safety. Uniform bedding. Reduced exercise, little control over environment

• Nutritionally complete pellets; decreased labor. No foraging for food, increased obesity, decreased satiety

• Uniform health status; decreased exposure to disease. Naive or compromised immune system

• Uniform genetics. Deleterious genes may lead to problems with health or reproduction

Positives of Enrichment– Increases activity

• Decreases boredom• Decreases obesity• Increases species-specific behavior• Increases learning and memory

– Decreases anxiety• Gives a sense of control over

environment• Teaches coping strategies• Decreases aggression• Increases reproduction and

mothering• Decreases stereopathies

Negatives of Enrichment

• Cost • Variability in experiment• Reduced visibility • Risk of injury• Increased aggression

• Individual acceptance/preference unknown

Sources of Enrichment• Positive human interaction

– Positive vs negative attitudes

– Training of technicians– Prior training of animals

reduces stress of procedures

• Interaction with conspecifics– Group housing– Non-contact communication

Mouse Enrichment• Bedding & nesting material

– Mixture of Carefresh and Paperchip– Nestlets, Enviro-dri

• Plastic tunnels and houses– Red or yellow– Watch for signs of aggression

• Plastic running wheels– Watch for aggression or obsessive behavior

• Paper tunnels and houses– Shepherd Shacks, paper towel tubes– Doesn’t elicit aggression

• Chew toys like small Nyla bones • Food treats

– Seeds (sunflower, safflower, pumpkin)– Cheerios – Seed blocks

Mouse enrichment video

Rat Enrichment• Bedding is needed but rats

don’t usually make large nests

• Plastic tunnels and houses– No sign of aggression

• Paper tunnels and houses• Chew toys like Nyla bones • Food treats

– Seeds (sunflower, safflower, pumpkin)

– Cheerios

Rabbit Enrichment• Chew toys—Nylabones, paper

tubes, hardwood blocks• Manipulatives/noise makers—

Shower curtain rings, Jingle balls, chains with washers hanging in cage.

• Food treats—Oat hay, fresh veggies (broccoli, parsley, cilantro, carrots) and fruit (apples).

• Tunnels, houses, and boxes• Split-level housing• Exercise runs or playpens

Enrichment for Staff?• Enrichment enhances

caretaker—animal interaction