Dr. Krisztina Nagy, PhD

Large Animal Clinic

Faculty of Veterinary Medicine, Szent István University, Budapest, Hungary

Horse Behaviour

• MSc (2004): Zoology, Faculty of Veterinary

Medicine, Szent István University

• PhD (2009): Postgraduate School of

Veterinary Science, Szent István University

• Working area: horse behaviourist,

biostatistician, researcher, horse riding

instructor

• Field of interest: stress-coping, stereotypies,

personality test

About me

• Evolution of horses (?)

About horses

Eohippus

-55-60 million years

-fox-sized, 4 toes

-teeth: eating leaves

-living in forest

Modern horse

-2 million years

-walking on 1 toe

-eating grass

-in grass-lands

• Wild horses (Equus ferus): Tarpan: extinct ( 1909),

przewalski horse/ thaki ( 1969)

• Zebra (plains zebra, Grévy's zebra, mountain

zebra), wild ass (ancestor of the domestic donkey)

Wild relatives of the domestic horse

• sole surviving genuine wild horse in the world

• not to be confused with, the mustang (America)

or brumby (Australia) a descendent from

domestic breeds gone wild

The przewalski horse

• 1969: last individual horse seen in the wild

• 1992: reintroduction to Mongolia

• ~ 1900 horses in the world (9 ancestors)

• 250 horses free-ranging in Mongolia, in

Hungary: 140 horses

The przewalski horse

• domesticated as one of the last mammals

(3000-4000 years ago)

• more impact on humans than most other

domesticated species - dispersion of culture and

language (Clutton-Brock, 1992)

Domestication

Previously

• They have been selected

for riding and haulage

• various economic

reasons (e.g. livestock,

sport or working animals)

Now

• most owners keep them

as companion animals

• they provide emotional

support to their owners (Wells, 2004)

• similarly to children, they

are often regarded as

family members

(Albert and Bulcroft, 1987)

Results of domestication

• Large scale of colour and size

• Reduced sexual dimorphism

• Oestrus during whole year

• Neoteny (Thoroughbreds)

• ~ 400 breeds

• Horse behaviour

• Ethology and animal behaviour

• Proximate („how”) and ultimate („why”)

questions

• New methods used in applied animal

behaviour science

• How to ask questions which can be

answered scientifically (how to form a

hypothesis which can be tested

statistically)?

What will we learn?

Ethology and animal behaviour

• 4 questions which should be asked of any animal behaviour (Tinbergen)

• How? (Proximate mechanisms) – Causation (mechanism, regulation)

– Development (ontogeny)

• Why? (Ultimate mechanisms) – Function (Adaptation)

– Evolution (Phylogeny)

• Example (feeding behaviour of the horse)

• 12-16 hours/day (small gastric, large caecum)

• early morning and late afternoon (+25% night feeding)

• patch foraging behaviour (selective)

• Social facilitation

(eats more in companion)

• Social learing

(foal from mother)

• Neophoby for new tastes

• Knows the feeding time

Feeding behaviour

Time budgets for horses

• Free ranging horses • Stabled horses

• small harem (1 stallion+3-4 mares+foals) or bachelor

group (2+ years old young stallions)

• Alpha-mare:shows the way to resources, initiating

activities

• dominant stallion: mate, protect + keep the herd together

Social animals

Stable mirror

Pair bonds

• Social groupings have evolved for individual

protection against predators, and cohesion is

maintained by a variety of mutually beneficial

behaviors such as:

• mutual grooming

• standing together

• tail-to-tail fly-swatting

Mutual grooming between

horse and human

Different levels of aggression

• dominance hierarchy in the herd/group (less

aggression)

• sometimes more stallion in the herd: more stable

harems (mares stay)

Home range

- 1 km² - 50-70 km² (not protecting territories)

- Scent-mark behaviour (communications between

stallions):the highest ranking animal often marks

last

The highest ranking animal

often rolls last too

Standing up • The main muscular effort used in standing

after a period of recumbency comes from

the hindquarters.

Sleeping

Interactive Play • foals and adult horses

• among foals

(locomotory play)

Play fighting (bachelor groups)

Perception: Vision

almost 350°

Blind area is influenced by the

horse’s head carriage

The visual field of a horse

Horse (left eye)

Human

Approaching a jump with the

horse’s head up

Human

Horse

Approaching a jump with the

horse’s head down

Compare to humans

- normal vision focus on far away objects with their

eyes relaxed (similar)

- more sensitive to movements than acuty (2/3 of

humans)

- dichromatic vision (max: 429nm, 539nm, Carroll et

al., 2001), 27 greyscale tones (Grzimek, 1952)

- sees well even in dusk

- acclimatisation is slower than humans (going out

from stall)

Colour vision • Dichromatic (horses)

(color-blind humans)

• Trichromatic (humans)

Chemoreception

• smell and taste are linked

neurologically

• horses familiarize

themselves with foreign

objects by smelling them

• sniffing: part of greeting

rituals between horses

• forced exhalations: helps

deep inhalations that

allow the horse to sample

odor molecules.

Flehmen response

Taste • they feel all the basic 5 tastes

• very important in selecting food

• use of peppermint essence (mask the

flavor of food and water): travel

Hearing

• very well developed

• direction in which the ears point:direction a horse’s attention is focused

• ears move independently of each other (10 muscles, 180°: locate the source of the sound)

• locate compares poorly with hunting species (Ca, Hu), but well equipped to hear faint noises (4.5 km)

• broader range than most mammals: 55Hz - 33kHz

• very low frequencies: earthquakes (hoof)

It has its attention on the handler

Touch

Vibrissae around the eyes and

muzzle

• Vibrissae around the eyes and muzzle have a rich afferent nerve supply

• detect distance, vibrational energy (sound), foal: find the teat, tactile information (along with lips)

• trimming of whiskers has been outlawed in Germany (2002)

• Sensitivity of the skin varies

• skin nociceptors: become less responsive if the stimulus is repeated at frequent intervals

Thank you for your attention!

Applied equine behaviour

research

Dr. Rezső Kovács, DVM, Phd student

Dr. Krisztina Nagy, PhD

You are wellcome to contact us

krezsoe@gmail.com

kris.nagy@gmail.com

Reproductive behaviour

Blanket on the mare

Reproducitve cyle of mares

• Puberty: 12–15 months old, free-

ranging: 3rd spring

• Seasonally polyestrous

• Cyclical active estrus (7.1 4.2 d.)

and diestrus (16.3 2.9 days)

• throughout the breeding season

(152 50 days)

• Foal heat: 8 days after parturion

Clitoral winking

in an estrous mare

Behaviour of the stallion

• first weeks: mounting attempts on their dams

• 3 month: erections

• 12 month: spermatozoa in testes

• 28 months: puberty

• Seasonality: all year

• But: responsiveness to sexual cues and

spontaneous erections in masturbating stallions

(penis being bounced against the abdomen)

increases in spring

Social groupings

of free-ranging horses

Leaving the natal band

• Colts leave natal band: time of the birth of their

siblings or when they are forced at 3 years old

• Fillies: search other stallions or stay (25%,

matrilineal dynasties)

• Mares leave (harem splits): winter/less grass

• Sneak matings: subordinate stallion with fillies or

subordinate mares (low conception rates)

Where social flux is constant

agonistic interactions must be

modulated • Horses adapt poorly to the constant introduction

of newcomers to a social group

• give time

• fence

• food:at distance

Introducing a new horse

• single-sex groups better than mixed-groups

• even number of horses

• large groups (shows less aggression)

• small groups: mix old with young

• 1 stranger with 1 inhabitant

• 2 strangers together

Maternal-infant bond

Foal rejection and Fostering

• bonding that occurs as a result of the

licking and nuzzling in the first hours of life

is very important

Twin foals (birth rate: 1:10 000)!

• Mule: donkey+horse

• Horse+zebra

Hybrids

Foal stands up quickly

Suckling

Grazing

Resting

Playing

Weaning

Weaning

When?

4-6 months

( free-ranging)

Weaning: profound stress

• When? How?

• Total separation: aberrant behaviors

reflect thwarted kinetic and foraging needs

• Partial separation (fenceline contact):

less vocalisation and locomotion

• Weaned in pairs (pair bonds)

• Management and feeding ! (Waran, 2004)

Abnormal behaviour

• Locomotor stereotypies:

Weaving (4%), box-walking (2%)

• Oral stereotypies:

wood-chewing(18%) crib-bitng (wind-sucking) (4%)

Stereotypic behaviour in horses

↔

(Wood-chewing horse ) (Crib-biting horse)

• Apparently functionless, relatively invariant

repetitive behaviour(Mason, 1991)

• Repetitive behaviour induced by frustration,

repeated attempts to cope and/or central nervous

system dysfunction (Mason és Rushen, 2006)

• only in captive animals: indicator of poor welfare

Stereotypic behaviour

(self-sucking diary cow ) (pacing tiger) (bar-biting sow)

New definition poses new

challenges to research

(tail-chasing dog) (self-plucked cockatoo) (wall-licking giraffe )

• the development of stereotypies is a long

process and little is know about their origin

• possible central nervous system dysfunctions

are difficult to study

• coping function of a behaviour detrimental to

the health of the animal is questionable

Aetiology and treatment of

crib-biting behaviour in horses

PhD thesis, 2009

Krisztina Nagy

Supervisor: Dr. Gábor Bodó

Why horses perform crib-biting

behaviour?

• Genetic background

• Neurobiological factors

• Housing & management

conditions, stress

• Learning from each other (?)

• Gastrointestinal dysfunction: Crib-biting is primarily

associated with feeding of concentrates

• Impaired basal ganglia function: Upregulated

mesoaccumbens dopaminergic system

• Coping mechanism relieving some of the stress (?)

Why horses perform crib-biting

behaviour?

Why horses perform crib-biting

behaviour?

Consequences

• Basal ganglia (n. caudatus, n. accumbens, putamen)

dysfunction may diminish learning abilities

– crib-biters were less successful, required longer time

to perform an instrumental task (Hausberger et al., 2007)

– learned association persisted longer during extinction (Hemmings et al., 2007)

• Crib-biters are more stress sensitive

(Bachmann et al., 2003, Minero et al., 1999)

• Is it more difficult to work with a crib-biter?

− tooth-erosion, weight loss

− gastric inflammation/ ulceration (Nicol et al., 2002)

− epiploic foramen entrapment colic (Archer et al., 2004,

2008)

→ decreased economical value, unsoundness

Health Consequences

Profound erosion of the incisor teeth of a severe crib-biter

Not successful (endogen opioid - serotonin system is

involved in the process )

Treatment possibilites

• Pasture

• Ad libitum hay

• Social contact

Prevention is most important!!

Aim of my PhD studies

1. Examine the risk factors of stereotypic behaviour (effect of a stereotypic neighbour)

2. Compare classification methods used in risk factors analysis (logistic regression - decision tree)

3. Differences in personality traits between crib-biting and control horses

4. To develop a crib-biting triggering stress-test

5. To assess the success-rate of the modified Forssell’s procedure, its implication for the welfare, and to compare the stress coping ability of surgically treated horses to that of collar treated, crib-biting and control (non-stereotypic) horses

Why horses perform crib-biting

behaviour?

• Plan a study

– How to select horses in the study

– What questions to ask, who to ask, how to ask

– What to measure/record

• Conduct the study

• Analyse the data

• Interpret your findings

• Publish!!

Why horses perform crib-biting

behaviour?

• Which risk factors to focus on?

– Use findings of previous studies in horses or other

animals!

– Have a hypothesis and a prediction (biological

interpretation)

• How to examine whether they are learning from

each other the crib-biting behaviour?

– Questions

– Methods

Study 1.

Risk factors associated

with crib-biting

• Questionnaire survey (298 horse, 9 riding schools)

• Factors usually used:

– Age, gender, housing & management, usage

– Unwanted behaviours (e.g. aggression)

• New aspect:

– Presence of an aggressive or stereotypic neighbour (not

further than 3 box)

Prevalence

This study In the world

Weaving 3% 4%

Box-walking 4% 2%

Wood-chewing 10% 18%

Crib-biting 5% 4%

More frequent in horses used for pleasure riding (2 –test,

p<0,001) (33 out of 126 horses), compared to competition

horses (12 out of 161 horses)

Logistic regression

Risk factor OR 95%-os CI p-value

Weaving neighbour 20,8 1,7-315,1 0.018

Aggression 11,4 2,4-82,9 0.005

Crib-biting neighbour 6,6 0,6-66,7 0.045

Control horses

Crib-biting horses

Crib-biting neighbour (OR=6)

Crib-biting neighbour

Present Not

Does this give an answer to our question

(crib-biting is learnt)?

Study 2.

Decision tree

Germany: from 2004

Denmark: from 2007

Switzerland: from 2012

Forbidden to use stalls