Saturday 20 February 2010

Pregnancy scanning of sheep

Here we are in the middle of the scanning season.

Pregnancy scanning has become an important management tool for the shepherd and farmer.Breeding sheep are scanned from ten to fifteen weeks from the date the tup was introduced to the flock. Anything tupped earlier than the alotted time can still be diagnosed in lamb but it is not so easy for the operator to be able to tell how many lambs she is carrying as the foetus' are too big. The same applies for anything tupped up to a month prior to the scanning taking place, a build up of fluid in the ewes uterus is a guideline to her being in lamb but again it is not possible to tell how many lambs she will be carrying.

Should the tups still be running with the ewes when they are scanned there is a possiblility that any deemed empty (barren or geld) may well be in lamb as the operator can not yet pick up the actual fertilisation of an egg! Another good reason to pull your tups off.

The wintery conditions did cause problems with tups being brought off the ewes this year. I always used to like to have the tups off by 5th January at the latest, that would see the lambing draw to a close by the end of May/first week of June. It is always good to know it is over. Whereas when tups are left running with the ewes lambs can still be appearing in the early summer and these later born lambs don't always grow quickly enough for the sales in the autumn.

An ultra sound scanner is used, very similar to that which would be used to pregnancy scan women. Sheep are scanned standing up, in a crate provided by the person who is doing the scanning. The crate is designed to ensure the sheep will be standing in the correct position to enable the scanner to access her tummy. The probe is moved over the skin infront of the udder region and the resulting pictures appear on a screen in front of the operator. Most scanning machines are now battery operated therefore enabling sheep to be scanned anywhere where there is penning available.

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I first saw sheep scanned in the late '80's and in those days there was a great deal of man handling needed. The sheep were caught, turned and sat on their backsides with the wool being pulled or cut off their lower bellies before then being presented to the scanning person in the sitting position to be scanned. Things have moved on a lot and today it is easier on both man and beast with the ewes just having to be fed into the crate one at a time whilst the operator sits (usually in an old car seat) and just has to reach his arm under the sheeps belly to be able to scan her tummy - no wool removal or anything - wonderful!

The skill of the person doing the scanning enables them to read the screen infront of them and work out how many lambs the sheep is or is not carrying.
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A keyboard is pressed enabling the computerised monitor to count each single, twin,triplet or geld reading which is taken therefore giving a total count and lambing percentage at the end of the proceedings.

The picture below shows the farmer putting his own mark onto the sheeps wool to represent what ever it is she is carrying. Most scanning operators do now prefer to mark their own sheep as they find it easier and quicker. Most hill sheep will have a single lamb in them so these tend not to be given a mark. Twins will be marked with a different colour to any which are geld enabling you to know what is what at a later date.
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You'll also notice that the scanning man has his hand on a handle which he is about to pull to enable the front of the crate to open and so release the sheep ready for the next one to walk in. He needs his wits about him as he also has to shut the front of the crate before the next sheep escapes and there are many of the woolly critters who try to seize the opportunity of a get away only prevented by the speed and dexterity of the guy operating the crate.

I'm sure I would be useless at it - by the time you've read the monitor, pressed the keypad, released the handle and then closed it as quickly as possible - reminds me of rubbing your tummy and patting your head, a thing I'm not capable of!


marshal said...

Its very helpful for farmers to scan the pregnancy of sheep and it is also essential.