Sheep – introduction
Information about the physical and behavioural characteristics of sheep.
Varietal range differences
Breeds commonly used in Australia can be divided into the following categories:
- Merino and Poll Merino bred specifically for wool (ultra fine, super fine, fine, medium and strong)
- Short Wool including the Poll Dorset, Ryeland and Suffolk
- Long Wool including the Border Leicester and Lincoln
- Dual Purpose Breeds including the Corriedale, Dohne Merino, Polwarth and SAMM (South African Meat Merino)and traditional first cross (Merino x Border Leicester)
- Carpet Wool including the Drysdale and Tukidale
- Terminal breeds including White Suffolk, Poll Dorset and Texel
- Shedding breeds include the Wiltshire Horn, Dorper and Australian White.
Schools that wish to maintain a sheep enterprise need to select a breed suitable for their local climatic conditions, availability of shearers and accessibility of markets for any outputs. Schools are encouraged to keep plain bodied sheep that do not need mulesing.
Physical characteristics
| Characteristic | Details |
|---|---|
| Size | Measured at the shoulder
|
| Weight | Varies with breed. 35-90kg but up to 150kg for breeding rams. |
| Age at adult size | Approximately 2 years. |
| Weight at birth | Dependant on breed.
This is an approximate. The weight is dependant on the age of the ewe, feeding regime of the ewe, breed and whether it is a single or multiple birth. |
| Gestation period | 150 days |
| Number of offspring | Normally a single lamb, except multiple births are common in breeds specifically bred for reproductive performance such as Booroola, Poll Dorset, Border Leicester/Merino cross and Maternal Composite breeds. The Finn breed are noted for very high fecundity, often producing “litters” of lambs (up to six!). |
| Range of breeding ages | Puberty varies from 8-12 months with breeds such as Border Leicesters /Merino cross maturing earliest and having an extended breeding season. Most ewes are mated for the first time when they are 15-18 months of age. |
| Weaning age | 3-5 months |
| Healthy characteristics |
|
Vision
Sheep have eyes on either side of their heads enabling them to have a wide field of vision, ranging from 191–306°, depending on the amount of wool on their head. This characteristic is typical of prey species. This is in contrast to predators that have eyes on the front of their heads.
The area to the side of the animal that is viewed by one eye is known as panoramic vision, in contrast to the narrow area in front of the animal where two eyes are used and known as binocular.
Sheep are sensitive to illumination, shadows and lighting and have a tendency to move from a dimly lit area to a brighter area. Bright light should not be shone directly towards the animal's face. Sheep are always sensitive to moving or flapping objects such as material and moving people. They have colour perception and will balk at a sudden change in colour. Sheep also have poor depth perception while their head is up and need to lower their head in order to look at a change in surface texture, drain or puddle.
Hearing
Sheep are more sensitive than humans to high pitched noises. Yelling, whistling, whip-cracking and clanging metal will increase stress in sheep and should be avoided when handling sheep in confined spaces. Rubber stops on gates prevent spooking sheep as a result of loud metal noises when gates slam.
Behavioural characteristics
Sheep are animals that are naturally preyed upon, meaning that they find comfort and protection in a herd with familiar sheep. Isolating individuals causes stress and may cause the animal to become agitated and aggressive. Mixing with unfamiliar animals or overcrowding can also induce stress.
The flight zone is the distance that sheep want to maintain between them and humans. A mob of sheep have a collective flight zone depicted by their individual characteristics, breed, age, environment and previous handling experiences. If an animal’s flight zone is penetrated, the animals will move away to regain a more comfortable distance from the intruder. Sheep raised in a pen with close contact to people will have a smaller flight zone and are usually calmer when being handled as opposed to sheep raised in a paddock.
Different breeds of sheep also behave differently when handled, Rambouillet tend to flock tightly together and remain in the group while Cheviots are more independent than other breeds.
Dogs are very intimidating to sheep and are often used as a herding method however they should never be used in a confined space as this can induce stress upon the sheep. If a dog is used with sheep in the school situation, it must be under the control of the teacher, farm assistant or person in charge of the activity.
Temperament
In general the sheep used in school situations should have reduced flight zones due to extensive and appropriate handling. Sheep showing difficult temperaments, in particular rams, should be culled and not used in the school situation. Students participating in a work placement situation should be supervised to ensure they are dealing with sheep that are well handled and have calm temperaments.
