January 4, 2009

Sheep Farm Husbandry - Lambing behaviour

Sheep, husbandry, lambing, birth problems, ewe & lamb behaviour at birth, birth site, lamb stealing by ewes, normal birth signs, helping ewes to lamb, helping newborn to feed.

By Dr Clive Dalton

Ewe behaviour prior to lambing
  • Ewes heavy in lamb and “on-the-drop” are very serene and slow up a lot in their movement around the paddock. Don’t hassle them. Always move them quietly.
  • They also become more vigilant and graze less. This restlessness lasts until the ewe finally selects a birth site.
  • Their appetite will drop because of lack of rumen capacity due to their massive uterus, especially those carrying multiples. But it’s not all an internal space problem as hormone changes are involved.
  • Let them settle into the lambing paddock as they’ll want to find a quiet lambing site when contractions start.
  • A few hours before lambing, a ewe will move away from the main flock to find a quiet birth site. These are special places and need to be recognised and respected by the shepherd.
  • Some ewes have been seen to select a birth site up to a couple of days before lambing.
  • Particular areas of lambing paddocks such as hollows or hill tops can be very popular spots, and many lamb mix-ups and mismothering happen here.
  • It may be necessary to fence these areas off after a while when they get muddy. This will avoid a great deal of extra work and frustration for the shepherd.
The birth site
Shepherds from the dawn of time have known that ewes like to choose a quiet place to lamb. But it wasn’t until Dr Ron Kilgour started to knock a numbered peg in the ground where a ewe had chosen to lamb, that we began to realise how important the birth site was in maternal behaviour and hence lamb survival. This is what happens on the birth site:
  • The ewe paws the ground.
  • She keeps turning round and round.
  • She lies down and gets up a lot.
  • Her waters burst and she gets up to smell the ground where they fell.
  • Then after labour contractions the lambs are born.
  • The ewe then gets up and licks the lambs.
  • A lamb may be finally delivered with the ewe standing licking another.
  • The ewe produces the afterbirth.
  • She will remain on the site till the lambs have suckled.
The key feature in the above list is the bursting of the ewe’s waters. We humans cannot see or smell this on the ground, but the ewe can, and they are a powerful anchor for her to stay on that spot.
  • Ewes vary in the time they spend on the birth site.
  • Experienced ewes will not move off the birth site until they are sure they’ve got things well under control. Some ewes with high maternal instincts and multiple births will spend a couple of days on or near their birth site until their little tribe is well bonded.
  • Other confident ewes will move off as soon as the lambs have suckled and can move with her. These ewes with good maternal instincts and experience seem to be able to count, and will not leave their lambs behind – going back to gather up stray twins or triplets. They stand with head down giving a low bleat and constantly nuzzling the lambs in turn and keeping them together.
  • Younger ewes with no previous experience will stay longer on the birth site, as they have the novelty of a lamb to deal with. If disturbed then these sheep panic more easily and take off leaving the lamb or lambs behind.
  • It’s good practice to leave newly-lambed ewes alone on their birth site, and only move them after a couple of days when they have clearly bonded and moved off to another area of the paddock of their own accord.
  • Shifting ewes or lambs in the middle of the birth process is a disaster, and will surely lead to mismothering of lambs and a massive amount of frustration and extra work, often late in the day for the shepherd.
  • It’s a good idea to spot-mark multiples at birth and then leave them alone. This helps to ensure correct mothering later that same day or in the next three days.

Lamb stealing by ewe before birth - burglar ewes
Often a ewe that has not lambed will steal a lamb from a newly-lambed ewe. It seems that her maternal instincts have got out of phase.
  • She can cause enormous disruption in a lambing paddock, as you often don’t know that she has not lambed until the day you find her with a lamb a few days old, and then a new one!
  • The only cure (when you discover the trick) is to shut her out of the lambing paddock until she has lambed or if she is near lambing, assist her to lamb.
  • Many shepherds have threatened to put burglar ewes in the killers’ paddock when discovered for all the disruption they have caused! What saves them is that they are exceptionally good mothers so their sins are forgiven.
Lamb stealing by ewe after birth
This happens regularly and studies have shown that even with close shepherding where ewes lamb fairly close together, you can expect from 6-18% errors in correct mothering-up of the lambs. This has serious implications when you need the correct pedigree of a lamb, that may for example become a future top widely-used sire.

Here’s what happened in a study at Ruakura Research Centre. The ewes were closely watched without disturbance for 24 hours (using torches during the night). A very experienced shepherd then went round in the morning and tagged the lambs according to what he reckoned were their correct mothers.

Key points from the table
  • The lambs in brackets are the stolen ones.
  • Theft was rife and the very experienced shepherd was duped!
  • 236 ended up with a correct single and lost her other twin.
  • 847 and 961 ended up with one correct lamb and a stranger.
  • 611 kept out of trouble by only licking her own lambs.
  • Amazingly, 169 ended up with her correct lambs after licking six others.
  • Lamb “I” disappeared completely.
The normal birth
Fortunately nature has being delivering young animals with no human help for eons, and the great majority of farm animals give birth naturally with no problems.
  • Once the birth process begins, it should be possible to keep a watchful eye on events without making the mother aware of your presence.
  • Don’t interfere unless you are sure there’s a problem.
  • The first signs of imminent birth in the ewe are a bulging udder and a swollen vulva.
  • She stands apart as womb contractions begin, positioning the lamb for delivery.
  • Fluid and the placenta appear at the vulva, and the placenta may bulge or hang from the vagina.
  • Most farm mammals are born in a diving position - with the front legs fully extended so that their knees are alongside their muzzle, making a streamlined shape for ease of delivery.
  • The two front feet of the lamb appear at the vulva first and behind them its nose.
  • The ewe may lie or stand for a few more pushes, and then the lamb arrives on the ground, usually with a bump and shaking its head.
  • As a general rule, once birth contractions begin, there is usually fairly rapid progress within 15 minutes.
  • If the lamb is born in a place that is at all dusty or muddy, spray or paint its navel and cord with tincture of iodine (iodophor spray). Try to disturb the ewe as little as possible.
  • It is wise to repeat the iodine treatment at 24-36 hours if conditions are particularly wet or muddy.
When things go wrong
  • The birth can be complicated by the lamb becoming stuck in the birth canal.
  • The chances of the birth process or mothering-up going wrong increase greatly if the ewe is disturbed unnecessarily, e.g. by people or other animals.
  • If the ewe has been down straining or if the membranes or part of the lamb have been protruding from the vulva for 10 minutes or more and no progress is being made, then you need to be concerned.
  • If she has been trying to lamb for nearly an hour, or you see a big head sticking out, then she needs assistance from someone with experience. If after inspection, you suspect major difficulties, then on a small farm near town it would pay to call your veterinarian for advice.
  • If the lamb is in the wrong position in the vagina, e.g. if its head is twisted to one side or a leg is bent back – this will be trouble.
  • Some skilled person with a small clean hand, should gently but firmly push the lamb back towards the womb, and straighten the limbs and body so that it is repositioned correctly.
  • It can be very difficult to do the repositioning if the ewe is straining and if the birth canal is tight and dry - it helps to use lots of lubricant.
  • Sometimes the hind feet come first, or there are twins alongside each other, and this can be very confusing.
  • When the tail comes first and the hind legs are extended forward under the body, this is a breech birth. They can be very difficult to deal with and prompt experienced or veterinary attention is usually necessary to deliver the lamb with minimal traction.
Lamb behaviour after birth
  • Sheep are classical “follower species” where the lamb follows the ewe most of the daylight hours, and this behaviour continues right up to weaning.
  • The lamb will even follow any movement immediately it is on its feet after birth. A very young lamb will follow the shepherd, the dog or the bike, and this can lead to mismothering.
  • Lambs learn to recognise their mothers by sight by about 3 days of age.
  • Good lamb survival depends on the ewe licking the lamb and the lamb finding the teat immediately after birth.
  • In high fertility sheep with multiple births, there is a greater chance of lambs failing to suckle in the first few hours after birth with consequent higher losses.
  • Teat seeking behaviour is important. The lamb has got to be determined to get on its feet, start nuzzling the ewe to find an area of bare skin and find a teat to suck on.
  • Some lambs find the skin under the front legs and waste time looking for a teat there, before moving to the rear end of the ewe.
  • A good ewe will encourage the lamb to move to the rear by standing still and nuzzling its rump and anal area.
  • Inexperienced young ewes will not stand still and they turn round to lick the lamb all the time. Lambs die of starvation often through this overzealous mothering.
  • Once the lamb has found the teat it will stand with head down reaching below the ewe, pushing upwards and once on the teat, wagging its tail while suckling. But don’t assume that a lamb wagging its tail has always found the teat – the proof of that is if its under belly is rounded and full.
  • Breeders once started to select sheep with four functional teats but this didn’t get very far unfortunately.
  • First sound then sight soon reinforces the ewe/lamb bond that was built initially on smell. The ewe recognises the lamb’s bleat, and the lamb learns the ewe’s bleat. This is important as lambs get older and spend time away from the ewe for short periods, e.g. with other lambs.
  • Lambs show great play behaviour especially approaching dusk when they race along fences and play “king of the castle”. They can often fall down holes and drown in water troughs doing this.
  • When danger is seen, the ewe first calls the lamb then checks its approaching identity by sight.
Helping the newborn get its first feed
  • After a normal delivery, it can be difficult to resist the temptation to help a struggling lamb to its feet and to help it suck.
  • As a general rule, it’s best to let the ewe and her lamb work it out for themselves for at least 4 to 6 hours.
  • If you don’t think the lamb has been able to find the teat within a couple of hours, then give it assistance, especially in bad weather.
  • If you do help the lamb get its first feed, don’t hold its head. It will struggle against this. Support the hind end so that its head is free and in about the right position to find the teat.
  • If this doesn’t work, sit the ewe on her rear end and stick the teat in the lamb’s mouth and squirt milk into it. If you are lucky it may start to suck in this unnatural position.
Disclaimer
This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

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