Spring is here. Daffodils are popping up along country lanes, birds are building nests and there’s just a hint of warmth in the morning sunshine. As a vet, lambing season is my favourite time of the year. It can mean long nights, early starts and can be physically demanding but it is also incredibly rewarding. If you own sheep, it’s always helpful to have some knowledge of lambing. But knowing when to call for professional help can make the difference between life and death. This article aims to outline the most common problems that we as vets may get called to during this period.
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Imagine you have a flock of around 20 ewes. It is three weeks before they are due to start lambing and over the past week, two ewes have aborted their lambs. This is the first time you have had any abortions so you decide it needs investigating. Infectious causes of abortion can cause problems year after year so diagnosing the problem may help save many future lambs.
The four most common infectious causes of abortion in the UK are Chlamydophila abortus (Enzootic Abortion of Ewes, EAE), Toxoplasmosis, Campylobacteriosis and Salmonellosis. Before phoning the vet, it is important to isolate the affected ewe and foetus and if possible, bag up and keep the placenta too as these are all required for sampling.
Unfortunately, it is often too late to be able to avoid any further abortions during the current lambing season and the emphasis should be on preventing problems in future years. This may be by vaccination, increased biosecurity or careful selection of new stock.
One chilly morning, you notice Brenda, who is two weeks off lambing, has developed a large, red swelling behind. On closer inspection, it becomes clear she has a vaginal prolapse. These are best treated as soon as possible so a quick call to the vet has help arriving swiftly. Thankfully it appears the prolapse has not been exposed for too long – the tissue is still healthy and can be replaced. The vet will administer an epidural to alleviate any straining and pain and the prolapse can be gently replaced with plenty of lubricant. A suture is then often used to help keep the prolapse in situ, though some farmers will use a harness or plastic retention device.
Twin lamb disease and hypocalcaemia
The flock is now a week off lambing. On your lunchtime rounds, you see Gertrude, who is expecting twins, lying down away from the others. When you approach her, she makes little attempt to stand, her ears are down and you can see fine muscle tremors across her nose. Looking closer, it appears that she is blind. Thankfully you attended a talk at your local vets on problems you may encounter at lambing time and you recognise that this may be twin lamb disease, otherwise known as pregnancy toxaemia and you know that what this ewe needs is glucose.
She has become ill because her energy expenditure in growing the lambs has exceeded her energy intake. In mild cases, oral treatment with a drench may suffice but sometimes intravenous glucose needs to be given. If you’re unsure or if there is no response to oral treatment, it is best to call the vet. In more severe cases, a dose of glucocorticoids may also be needed to help reverse the metabolic derangement, but this carries a high chance of inducing lambing early.
However, in this case, twin lamb disease wouldn’t be your only cause to consider. Hypocalcaemia can also strike late-gestation ewes for similar reasons – they are using a lot of their own calcium to produce colostrum which can cause them to become weak and recumbent, though in contrast to twin lamb disease, blindness is not usually seen. Instead of glucose, these ewes need calcium. This is often given intravenously, by a vet, but it can also be given under the skin. This method takes longer to generate a response (hours rather than minutes if given intravenously) so should only be used as a stand alone treatment for mild cases.
Problems during lambing
Lambing has begun! Most of you will be familiar with the signs that a ewe is about to give birth – they separate themselves off from the flock, may become restless, strain or lick their lips. But how do you know whether things are going well or if you should intervene?
Firstly, intervention that is too early or carried out by inexperienced hands, can cause severe damage to the ewe and lambs. Often, just giving a ewe more time, especially if she is a first-time mum, may be the best way forward, but there are some situations which you need to be on the lookout for. If you notice a ewe that has been straining for over an hour without producing any sign of a lamb, if you can see a lamb in a normal presentation (two front feet and a nose coming first) but it hasn’t been delivered within around 10 minutes, or if you can only see a head, one leg or a tail, then there may be something wrong. If you do decide to have a feel yourself, it is important to wash your hands in diluted disinfectant solution, ensure your nails are short and ideally wear arm length gloves. The ewe should be gently restrained and your hands well lubricated before examination. Go gently, and if in any doubt, stop and phone the vet.
There are many reasons why a ewe may not be progressing normally with lambing.
Ringwomb is an incomplete dilation of the cervix. Gentle manual dilation can be attempted but if no progress has been made within around 10 minutes, a caesarean will be required. Medical therapy is usually ineffective.
Uterine torsion is when the uterus twists upon itself, making a normal birth impossible. It is rare and manual correction is tricky and unlikely to work. A vet will usually decide that a caesarean is the best way forward.
Oversized lambs can get stuck in the birth canal, usually at the shoulders or hips. Being able to assess if a stuck lamb can be born vaginally is a skill developed through experience and if in any doubt, a caesarean may be needed.
Malpresentation of lambs is common – we see ‘head-back’, one front leg back, head only (hung lamb), breech (bottom first), back leg(s) first and tangled twins or triplets. It is common to administer an epidural to the ewe in order to allow the lambs to be repositioned and a lot of the time, once in the correct position, these lambs can be born normally.
Lambing has finished and you have a barn full of ewes and lambs all ready to be turned out. But it is still important to watch the flock carefully. Both ewes and lambs can suffer with post-lambing problems and it’s vital to act quickly if you notice an issue.
You’re just about to head in for supper when you notice Bonnie, who lambed the previous day, has completely prolapsed her uterus. This is definitely one that warrants a vet visit immediately. If possible, carefully confine the ewe to a small, clean pen but be careful to avoid any trauma to the uterus.
Similarly to the vaginal prolapse, the uterus will be replaced under epidural and a suture put in to help prevent recurrence. Uterine prolapses can occur either straight after the birth – often a large single lamb. It can also occur a day or two later, in cases where there may have been vaginal trauma at the birth leading to swelling, pain and continued straining.
Three days later, out in the field, Dotty isn’t looking like her normal self. She is subdued, she doesn’t come up to eat the sheep nuts and her lambs appear hungry. There is also a particularly unpleasant smell emanating from her rear. When you check her temperature, it is reading 42°C. Metritis, or infection within the uterus, can occur after manual intervention at lambing time, especially if hygiene procedures haven’t been followed. If caught early enough, antibiotics will bring about a rapid recovery.
Sometimes anti-inflammatories or fluids are required as well so if you don’t have the appropriate treatment on the farm, or you’re worried about a ewe’s condition, it’s best to call the vet. Don’t forget the lambs too – if mum is sick, they will need to be stomach tubed milk.
If lambs don’t feed, particularly if they miss the vital colostrum within the first few hours of birth, they can become weak, hypothermic and prone to diseases such as watery mouth (an E. coli infection), navel ill (infection of the umbilicus) or joint ill (when infection that has often entered at the umbilicus spreads to the lamb’s joints).
Metritis can also occur with retained foetal membranes. This is the placenta of the lamb and is usually passed within a couple of hours of lambing. If it isn’t, it can decompose inside the ewe and set up infection.
The flock have been out in the field now for around 4 weeks and the lambs are growing well. This time it’s Ester. She’s lying down more and when she does get up and walks, she looks sore and stiff behind. You go over to check and find she has a clear case of mastitis – one side of her udder is hard, red and swollen.
A quick call to the vet and you go and collect some antibiotic and anti-inflammatory injections for her, alongside instructions to regularly strip out the quarter. Mastitis will occur when bacteria enter the udder and set up infection, which is more likely in dirty environments or with trauma to the teats often caused by the lambs themselves. If multiple cases are encountered in a year, milk sampling can help identify the bacteria responsible and target treatment more appropriately.
Generally, the decision to call a vet out at lambing time is often dependent on how experienced the farmer is rather than necessarily the specific condition needing to be treated. Vets follow a code of ‘do no harm’ and this should be applied here too – if in any doubt, call for help and only intervene yourself if you are confident in the situation. Everyone wants to see happy, healthy ewes and lambs out in the fields – it is what Spring is about after all – so enjoy this time of year and work with your vet to ensure a good outcome
Please note that many drugs used in sheep are not licensed and should only be used under veterinary guidance.