Springtime is associated with the sight of lambs in the fields. Although lambing can begin as early as December and go on until June, most flocks have their lambs in early spring. Ewes are generally only in season once during the year (apart from a small number of breeds), so the majority of lambs are born at a similar time.
Lambs are born after about 4.5 months, or 145 days after impregnation. Many ewes are able to deliver their lambs, without assistance, in the field. However, farmers may bring some of their flock indoors at lambing time, in order to be able to monitor them closely; ewes having their first lambs, and those with multiple births are likely to need more attention. Monitoring a lambing flock is very labour-intensive, as the farmer needs to be on hand all the time in case of issues. At this time, extra staff/help is invaluable if it’s possible to arrange.
Well before lambing time, farmers will have been planning for strong and healthy lambs. The outcome can be influenced by genetics, and rams may be chosen for their ability to produce offspring well-suited to the environment/surroundings.
Good body condition pre-breeding can make a significant difference to the outcome, such as heavier lambs. Monitoring body score condition during pregnancy is also important, as any individual that needs extra attention can be identified. Make sure that your flock have enough space when eating – less dominant individuals may be losing out if not.
Making sure that vaccines/boosters (e.g. for clostridial infections) are up to date will ensure that your ewes are in good health to begin with. It’s also important to rectify any trace element deficiencies – these can be identified with blood sampling. Most ewes won’t need to have worming treatments, however, those that are not at peak health/carrying multiple lambs may need them pre-lambing, due to a dip in immunity at this time.
Pregnancy and Birth
Farmers can find out how many lambs a ewe is carrying by scanning. Finding this out means that the farmer can split the flock as needed, and provide the right level of nutrition – ewes with one lamb need less intake than those having two or three. The desired number of lambs will often depend on the type of farm/environment.
It can depend on the breed, but new mums often will have just one lamb. But twins are not that rare, and more than two lambs are common in certain breeds. Ewes usually start breeding at about 2 years old.
Soon after birth, ideally, a lamb needs to stand up, and latch on to its mother’s teat. The first milk/colostrum contains antibodies as well as nutrients, so is extremely important for the lamb to have this. If this doesn’t happen naturally, the farmer may collect the colostrum, and tube-feed it to the lamb. Although the mother’s supply is best, it’s possible to use a back-up supply (frozen surplus from the same flock), if available. It’s worth having a supply of powdered colostrum, if all else fails, however, it is a last resort. Consult your vet for the most suitable type.
There are times when a lamb or ewe does not survive the birthing process. When this happens, farmers may try adoption. An orphaned lamb can have birth fluids placed on it, so that a ewe that has lost a lamb, or one that only has one, may accept the new lamb as its own. Also, a ewe that is unable to cope after a multiple birth may have a lamb transferred to another mother.
Stress can have a significant effect at lambing time. Being able to control when they can give birth would benefit sheep in the wild – consider the risks to newborn lambs from predators. However, housed sheep may also do this, due to stress from other sources, such as increased handling, mixing of different groups, high stocking density, competition for food, and interaction with dogs.
By minimising these factors, you can help to provide a low-stress environment for not only birthing – this also improves the level of post-natal care the ewes give/show. If ewes can care for their lambs effectively, this reduces the intervention needed from farmers/handlers, saving time in the long run.
Once you know that a lamb is strong enough, and is being cared for appropriately by its mother, it’s time to go back into the fields. Marking lambs and ewes can help to keep track of who belongs to whom – however, lambs are also fitted with a lifelong ID ear tag.
The ewes will have access to good grass, enabling them to produce the milk needed – they can also have supplemental feed as required. As part of the build-up to weaning, lambs may be given a creep feed, which can be provided in special feeders designed to prevent adults from getting to it
Issues for lambs
Birth is a risky time for all animals, and sheep are no exception. It’s possible for lambs to sustain fractured ribs during a difficult birth – this can negatively impact their ability to suckle, so intervention may be needed, such as tube-feeding them colostrum, and giving pain relief.
Fractured limbs may also occur, due to excessive force used during lambing. This risk can be reduced by pulling equally on both legs, and placing any ropes used above the lamb’s knee. You will need to contact your vet to apply a cast, however, the stabilised fracture will heal quickly as the lamb is young.
Colostrum intake is also very important in preventing a bacterial infection called watery mouth, which is more commonly seen in indoor lambing. Caused by E.coli ingested from the lamb’s surroundings/lambing shed, it results in the lamb producing excess saliva, and deteriorating rapidly. Antibiotics are used to treat it, but in addition to ensuring that lambs have received appropriate colostrum, keeping the lambing shed/environment clean and hygienic is extremely important in preventing this issue. Another problem that can be caused by unhygienic conditions is navel ill, an infection of the umbilical cord site – this can be prevented by applying an iodine solution.
Newborn lambs are at risk of hypothermia, particularly those that are small. They are also at risk if they are exposed to windy/wet conditions, or are having difficulty with suckling colostrum. The treatment needed will vary on how much time has passed since birth.
Issues for ewes
It’s possible for ewes to suffer from milk fever, or hypocalcemia. This can be due to low calcium levels in the diet, or the inability of the individual to utilise her stored reserves, and often occurs pre-lambing. The ewe will initially be unstable on her feet, and then progress rapidly to being unable to stand. The condition can be treated by a calcium injection under the skin, but close monitoring may be needed in case of a reoccurrence/relapse.
Another issue that ewes can have is twin lamb disease, whereby the ewe has an inability to keep up with the energy needs of her unborn lambs. Injections and oral treatments/rehydration are used for this condition, which is characterised by the individual appearing to be blind, unaware of surroundings, and not wanting to eat, or be able to stand.
During the birth process, particularly if there is excessive straining, ewes can suffer a prolapse of the uterus. In these situations, urgent vet intervention is needed – in the meantime, the ewe needs to be kept away from the rest of the flock, and the uterus kept protected/clean. There are harnesses available to prevent reoccurrence.
For the best results for your flock, being prepared is vital. Suitable antibiotic injections, painkillers, calcium injections, iodine solution, and drenches are all essential stock items, as well as such equipment as gloves and lubricant. Stringent hygiene practices are also needed to minimise many risks involved.
As can be seen, nutrition can influence the outcome/continuing health of your flock. As well as analysing the food given to ensure the correct nutrient levels are provided, it may be worth monitoring how the flock are utilising it by taking blood samples. You can ask for advice about nutrition from your vet, if you have concerns.