Understanding Sheep

Ancestors of the sheep you see today, grazed mountains and foothills of arid and semi-arid areas. In order to survive they developed certain behavior patterns. As farmers, we need to know and make use of this behavior, so we can keep these animals in an often totally different environment, as stress free for the animal and the shepherd as possible.

What constitutes a sheep? We know it is:

  1. a flocking animal
  2. a ruminant
  3. wool covered
  4. relatively defenceless
  5. very vigilant

So what is a flock? One.... two... .three.....?

A flock of sheep is only a flock, when there are four or more of them. Several experiments have shown that this is so. One of them at Ruakura, the animal research station, just out of Hamilton by Dr. Ron Kilgour, who tried to learn how a different number of sheep negotiate a maze. One sheep took time, showed signs of stress, but learned the problem quite well. Two sheep went different ways and took longer to learn, three were even worse since they spread out rather than gather, but using four or more sheep they moved as one and learned even faster than a single sheep. So for dog trials three sheep are always used, as this is a good test for the dog.

Skipping over the ruminant and wool covered points, number 4 and 5 need further examination.

Since it looks as if sheep exist almost solely as a food source for canine and feline predators, it is actually amazing that sheep as a species have survived at all.

So how have they done it?

Being defenceless, sheep need to be very vigilant at all times. They have vision over virtually 360 degrees even when grazing. Being vigilant means they take flight and mob together with any unexpected movement or sound and seek the high ground.

Superficially this behavior might seem stupid, but for sheep this flocking instinct makes good sense. It is safety in numbers, since it is harder for a predator to pick out one of a group, than attacking one or two strays.

This strategy of keeping together and the fear of dogs, makes it easy to muster a large mob of sheep by a single shepherd and a team of well trained dogs. It also means that, in confined spaces, it is easy to stress sheep with dogs.

In the breeding season, the task of the ram is made easier because of the flocking instinct. Find the flock and sniff-hunt all the ewes that are ready to be mated. Young sheep, by staying together with adults will learn the about the sheep tracks, the best feeding ground, shelter and water. When encountering a new or strange feed, two or three sheep will sample the food and for 48 hours no other sheep will touch that food. If nothing happens the rest of the mob will start eating it. If one of the test sheep dies, the mob won't touch that food. Moreover, the mob will remember this for about five years. This behaviour has so far only discovered in sheep. So they are not so stupid after all.

In temperate regions, sheep are seasonal breeders (there are some breed exemptions like Merinos, Dorsets and Finns) The start of breeding is related to the declining daylight hours in the Autumn. Here in the Waikato the mean breeding season starts around March 25. With the arrival of the rams, the waxy substance in their fleece, has a turn-on effect on the ewes, the so called "ram effect". Ewes will come in oestrus in synchrony. The result in the spring (after a gestation period of 150-153 days) is that there will be a peak in lambing. The milder temperatures then will facilitate grass growth and plenty available feed for the ewes.

Back to the rams in Autumn, when they move amongst the ewes, sniffing their rear ends. If the ewe is not ready for mating, she will squat and urinate, while the ram gives the lip curl, she moves away and will not be followed. If the ewe nears ovulation he will move after her and keep near, till she will stand for mating. On approaching of the mean date older ewes will seek the ram out and it is not unusual to see a ram, surrounded by ewes with their rear end towards him. Ewes will stay in heat for 6 to 18 hours and if not mated cycle again 17 to 21 days later.

Mating makes considerable physical demands on the ram, so he needs to be in good condition and health but then he will easily serve a 100 ewes or more. The mating season will last from March/April to August. Although the sex drive is a powerful one, hunger comes first and a ram will loose only a little condition over the mating period.

At lambing time, a ewe will seek a birth site 24 to 48 hours before parturition. After birth a good Coopworth will stay at least 24 hours on the birth site. Adequate time and undisturbed conditions are needed to allow bonding. Multiple births will take longer than singles. There is a difference between breeds though and Merinos, for example, will leave the birth site within a few hours, usually leaving a second lamb behind.

In the early period after lambing ewes will recognize their lambs purely by smell, later on ewe and ewe and lamb will recognize each other by sound. Placenta and membranes are usually eaten, but not always.

Sheep are followers, and the lambs will follow the ewes from the lambing site within a few hours. It is essential for the lamb to get its first suckle as soon as possible to give it energy and immunity to a range of diseases. It also helps the bonding process essential for survival, growth and proper lamb care.

Sheep are remarkable animals that easily adjust to different conditions and handling, including considerable pressures at docking (cutting off tails and castrating in non-breeding flocks), shearing and dipping (showering with organophosphates to get rid of lice and protecting against blow-fly).

Sheep give us a variety of products that include meat, soft leather, wool, a range of pharmaceuticals, soap (tallow), lanoline, glue (from the bones), strings for musical instruments and before the advent of rubber, condoms.

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