Gestation in Soay Sheep
BREEDING SEASON
We have found that breeding season for Soay sheep often coincides with "the rut" found in deer, which normally occurs in October and November in our area. Most ewe lambs tend to come into heat (estrus) in November, while older ewes might come into estrus in October. We prefer not to put our breeding groups together any earlier, so as to avoid February lambs.
GESTATION LENGTH
I have been keeping track of actual length of pregnancy in our American and British Soay sheep for years, and have found that gestation in Soay sheep can range from 147 to 155 days, with an average of 150 days. My own data tallies with other records. You can rough estimate gestation to be about 5 months.
FEEDING DURING GESTATION
We feed unlimited amounts of good quality grass hay during the times our pasture growth slows. During flushing and the early part of gestation we supplement their good quality grass hay with limited quantities per day of high quality alfalfa hay, and then taper off the amount of alfalfa for the next 3 months to just a bit per ewe. During the last month we increase the amount of high quality alfalfa hay again. Our sheep are always on pasture, with access to green grass all winter long. It's very important to make sure that their salt feeder is kept full; we use a half and half mixture of kelp and sheep salt with minerals. Not making this available can cause a selenium deficiency in the lambs known as white muscle disease. Never use an all-purpose livestock salt block or mineral mixture with Soay sheep because it contains too much copper and can kill them. Sheep salt is a mineral mixture specially formulated for sheep and has the right amounts of copper; Soay sheep can die from ingesting salt/mineral mixes made for other livestock.
HOW MUCH FEED IS ENOUGH?
Feel the backbone of your sheep; the backbone of a Soay should feel much like the knuckles of your clenched fist. Bony ridges are normal, but not too bony. It is helpful during the winter to butcher a few rams that don't make the grade as breeding stock, and before you butcher them, feel their backbones. Once you have butchered, you can see just how much fat is on a sheep compared to the amount of bone you felt.
KETOSIS
While we have never had ketosis show up in any of our Soay ewes, we did have it in a couple Shetland ewes in our first year of shepherding, back when we grainfed our sheep. We no longer grain feed, for the reasons stated on our Feeds page.
If ewes are not fed properly during gestation, ketosis (pregnancy toxemia) can result. Ketosis is often called twin lamb disease, and results from the ewe not receiving enough nutrition during late gestation when her twins or triplets are taking so much from her. This is a tricky time, as the lambs are taking more space in her body, making less room for her dinner. Therefore, her feed needs to be of a higher nutritional value at this time, and provided more often. If the ewe is fat before coming into late gestation, she will use the fat in her body to turn into calories, which will happen faster than she can utilize and cause her to become ketotic. Keeping the ewe fit and in good condition during gestation, but not fat, is the key, as well as increasing her plane of nutrition in late gestation.
Symptoms of Ketosis are a suddenly listless ewe, not wanting to get up and looking rather sleepy. She may have an acetone smell in her breath. Most people cannot smell this, but some can. Getting glucose into the ewe immediately is important, or she may die. This can be done via a solution from the vet, or you can use molasses mixed with some grain (if you use grain) or molasses mixed with leafy alfalfa. Warm water with molasses added to it will also help, but is not the solution in itself. In a severe case with a valuable ewe, call in the vet, who can set up the ewe with intravenous glucose. This will turn the ewe around very quickly; we had a Shetland ewe who was so near to death when we discovered her condition (it does happen quickly) that my husband had his knife out, ready to cut out the lambs, when the vet arrived literally in the nick of time. She set up the ewe with an IV, and within minutes the ewe was up and fine. Within a few hours, the ewe had ripped out her IV and escaped her pen. We realized that she had recovered when we were having difficulty catching her as she ran around our pastures; this is truly a quick fix!
Your vet can sell you some strips to check for ketones in your heavily pregnant sheep. We have never had to do this, as we have never had ketosis in our Soay flock, and never again in our Shetland flock after that first time.
VACCINATIONS
While some Soay shepherds vaccinate for this, that and everything else, we only vaccinate with CDT, and I'd like to get to a point where we don't even do that. Not only do we want our sheep to not rely upon modern medicine to survive, we expect them to flourish without it! Until we are "there" we continue to vaccinate with CDT yearly; about a month before the first lambs are due. The C & D in CDT is for "over eating disease" and we don't have a problem with that due to the fact that our flock is grassfed only; we give it for the Tetanus only. We do not vaccinate lambs, knowing that young immune systems do not need the shock and interference, and we have never had a problem due to lack of vaccination.
