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Studying Animal BehaviorStudying Animal Behavior

Camie Heleski

Department of Animal Science

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In order to better understand animals, we need to carefully study their behavior.

The study of animal behavior is referred to as ethology.– “pure” behaviorists, such as in zoology, tend to study

animals in their native state; e.g. mate selection in bird species or foraging strategies in antelope species

– “applied” ethologists tend to study the domestic species, or exotics kept in captivity and might examine how housing influences behavior, or what behaviors represent an animal experiencing pain

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Ethogram - the complete description of behaviors shown by an animal.

Time Budget - how the animal divides up its day into component behaviors.– resting– eating– locomotion, etc.

A good stockperson knows these features even if they don’t know the official names

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Analyzing the evolutionary ecology of the animal can tell us a great deal about the animal’s behavior.

For example, the horse evolved as a creature of prey and has a tremendously strong flight response. It also evolved on the great plains where running first and “asking questions” later was very effective. Donkeys evolved in mountainous terrain and rarely run in panic.

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An animal’s behavior tends to adapt to its physiology (or visa versa).

For example, the wild Przewalski’s horse can survive in regions that cannot sustain ruminant animals.

Though ruminants are more efficient than horses in extracting usable energy per given weight of food , there is a limit to how much poor quality feed a ruminant can move through its system per 24 hr.

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Horses lie down less than most ruminants (about 5-8% in most studies).

Energy expenditure in horses is about 10% less when standing/ resting than when lying down. By contrast, sheep & cattle use 10% more energy standing than lying.

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The domesticated species have a greater range of acceptable management that suits their behaviors. The horse, cow, chicken, sheep & pig are very adaptable and many years ago, made a “decision” to form an alliance with man, while many of their counterparts became extinct.

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Herd animals (like horses) and pack animals (like dogs) are easier to “dominate” and train because of their desire to keep harmony in the group. If the trainer learns to read their body language, it is a fairly easy process. (Some say they bond with us for lack of better company .)

More solitary animals (such as cats) have much less desire to keep the peace of a pecking order.

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Play behavior... primarily in juvenile animals supposedly preparatory for life skills some species (e.g. dog) seem to be in

arrested development

What does it mean when we do not observe play behavior in juveniles?

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Important to understand the senses of the animal you work with

For example, vision in horses is mainly monocular, but field of vision is very large– about 65 degrees binocular in front– about 150 degrees monocular on each side– about 3-5 degrees blind spot directly behind– has direct application to safely working with

them

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Most animals have much better senses of smell and hearing than we do.

Again has implications for safely working with them. Sometimes we have to anticipate what they will find frightening.

Dr. Temple Grandin, CSU, has done a great deal of work in slaughter houses trying to put herself in the animal’s place to minimize fear and distress.

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They used to say most of our domestic animals were color blind, we now realize through various research projects that their color vision is not as keen as ours, perhaps, but is definitely more than black and white– e.g. horses discriminating different colors for

food rewards– dairy cattle discriminating different color

uniforms for type of treatment

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Back to some specific studies... Ethogram of weanling horses...

– lying down sternally– lying down recumbent– standing, dozing– standing alert– eating hay or grain– grazing– drinking

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– defecating– urinating– investigating– friendly social interaction– aggressive social interaction– mutual fly swatting– mutual grooming (has actual HR effect)– rolling– scratching– playing with an object– aberrant behavior: pawing, biting wall, licking wall,

bucking/rearing

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Stalled weanlings laid down much more than paddock-reared weanlings (about 20% compared to about 5%). This correlated with a decrease in bone density in the stalled weanlings. (probably due to less loading on their legs)

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Paddock reared weanlings spent about 18% of their day grazing (even when hardly anything worth eating); they spent about 4% of their day in social encounters (such as mutual grooming) and spent more time moving around. Stalled weanlings looked better from the standpoint of showring standards, and didn’t care when they were separated from horses stalled next to them (which made them a bit easier to handle).

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Another MSU study looked at 2 year olds kept in stalls or out at pasture and compared ease of “breaking out.” The pastured horses took shorter times to accept the saddle and the rider and were less fractious during the ride. Was this because the more enriched environment enhanced the learning pathways or because the pastured horses “burnt” off more energy prior to being ridden each day?

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This past summer we looked at weanlings and collected blood and saliva to determine if saliva could replace blood for analyzing cortisol levels. Heart rates related to level of distress they displayed during the restraint and collection procedure. An anesthetic cream was found to make significant differences on their perception of pain/pressure during the bleeding process. (Data still being analyzed but looks promising.)

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Beef calvesBeef calves

A study by Haley & Stookey (Saskatchewan) found that beef calves initially treated with Kant-Suk nose plates vocalized 84% less than controls, walked 79% less, spent 24% more time eating dry food and consequently showed less post-weaning weight loss

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PigsPigs

Many studies (Mendl et al., Zanella et al., Lawrence et al.) have examined nest-building frustration pre-parturition in gilts

They show an increase in plasma cortisol and ACTH if compared to gilts in larger, straw-bedded pens

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ChickensChickens

Study by Yue & Duncan found that thwarted nest-building behavior in layer hens manifests itself as stereotyped pacing

Furthermore it contributes to increased calcium deposition on egg shells (not observable in white eggs, but noticeable in brown eggs)

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In conclusion, the work of the ethologists will be important in establishing the priorities for optimizing production while maintaining appropriate welfare standards.

Quantifiable science is needed to back up or refute people’s opinions about the appropriate ways to manage our domestic species.