15. Sheep Behaviour Flashcards
What type of environment did sheep evolve from?
A desert of a mountain grassland habitat with low water needs
Why type of dam precocial offspring relationship is displayed?
A “follower” type
- Strong imitation between young and old in establishing range systems
What type of breeders are sheep?
Seasonal breeders
- separate male sub-group structure at certain times of the year
Are sheep social?
Sheep are strongly social
- Group with about 4-5 other sheep, when grazing, to maintain a visual link with each other
- Each sheep throws its head to check the position of other sheep; constant monitoring is what keeps the sheep in a mob as they move along grazing together
How can psychological stress induced by isolation be reduced?
By providing a mirror
- sight of other sheep has stress-reducing properties
Sheep vision
- large pupils of a somewhat RECTANGULAR shape
- built-in wide angle lens which enhances peripheral vision
- certain amount of vertical vision is sacrificed (ex. may not be able to see a predator up in a tree) - eyes placed to the sides of the head
- better panoramic vision (wider field)… 330-360
- possibly due to it being a prey species; easier to see a predator out of the corner of one’s eye - Binocular vision of 25-50 (difficulty judging depth
- Able to distinguish between black, red, yellow and white
Sheep hearing
- Sensitive to high pitched noises
- Increased release of stress-related hormones in response to sudden loud noises
- ex. barking dogs - Become nervous and difficult to handle when stress hormones are elevated
- so it is useful to avoid loud or shrill noises when handling or moving sheep - Can amplify and pinpoint sound with its ears
- Sounds arrive at each ear at SLIGHTLY DIFFERENT TIMES with a small difference in amplitude which the auditory system can process into a directional signal
- further refined by moving the ears, head or the entire body
Sheep Smell
- More highly developed olfactory system than humans
- incorporate olfaction more completely in their interaction with their environment - Use smell to identify other sheep
- how ewes will pick out their own lamb in a group - Smell is also used during mating
- flehmen response to detect ewes in estrus - May use smell to locate water and to identify subtle or major differences between pastures and feeds
- ex. prefer to avoid grazing near where other sheep have defecated
- ex. will select fresh feed in preference to spoiled feed
Sheep taste
- Have the ability to differentiate between feedstuffs
- Sweet and sour plants are preferred and bitter plants are commonly rejected
Sheep touch
- Nose, lips and mouth readily lend themselves to feeling behaviour
- body is covered in wool - Lambs seek body contact with their dams and ewes respond to the touching behaviour in various ways
- ex. milk let down in response to nuzzling/suckling stimulus of lambs
Social organization and dominance hierarchies in sheep
- In a flock of grazing sheep there is often little or no sign of dominance, however…
- In small domestic flocks, sheep will compete for small amounts of food by pushing and shoving
- In competitive feeding situations, a linear hierarchy forms with a less rigid structure - Form strong stable social groups
- influences grazing patterns
- animals not dispersed randomly in any environment
- sometimes a strong bond forms between 2 animals and they become mutually dependent - Dominance fights occur more within single-sex, single-aged groups than in mixed sex groups of varying ages
- Social system is shaped by anti-predator and foraging strategies
- Older animals more likely to be involved in fights
- Family groups are less likely to display fighting and attention-seeking behaviours
- Different breeds have different flock structures
- Merinos are a tightly knit flock and rarely form sub-groups
- Southdowns form few sub-groups
- Dorsets always form many sub-groups
Sheltering behaviour sheep
- If shade is available in summer, it is used
- If not, they stand in groups, shading their heads under the flanks or between the hind legs of adjacent lambs rather than lying down - Sheep tend to graze into the wind on treeless plains in hot weather
- But on cold wet days, they huddle in the down-wind corner of the paddock so shelters should be placed there
- Least used shelters are typically near roads, human activity and paddock ends
Camping behaviour sheep
- Sites chosen for DAY camps DIFFER from NIGHT camps
- Bedding habits = known as camping behaviour
- Because of camping behaviour, a large proportion of feces is dropped at the site so plant nutrients are transferred from the pasture to the campsite
- Build up of internal parasite eggs at the campsite as well
- May have to fence-off campsites and force sheep to move to other areas from time to time
What are the two primary grazing periods for sheep? What permits very close grazing?
Two primary grazing periods:
- Early morning and late in the afternoon
- Graze 5-10 hours/day
- Affected by day length, environmental factors, breed, availability of pasture and water, and topography
Cleft upper lip permits very close grazing
- Jerks its head slightly forward and up to break stems, leaves and grass blades against the dental pad and lower incisors
