Lambing Preparation - For a Healthy & Environment Friendly Flock!
We’ve all seen the newspaper articles about ruminants burping greenhouse gasses asbeing one of the greatest single contributors to global warming. Well, to an extent this is true – but an efficiently managed flock can reduce its environmental impact to an almost negligible level and, at the same time, significantly raise its profitability for the farmer.
With over 15 million ewes in the UK and an achievable conception rate of 200%, we could expect to see as many as 30 million lambs skipping about the fields in Spring time. The sad fact is that each year around a quarter of these potential lambswill either be lost before they are born, or will fail to reach productive adulthood: their lives and all the resources that have gone into their breeding are wasted. The environmental cost that this represents is something that all livestock keepers should aim to reduce, and the key is to achieve ‘biological efficiency’. Put simply, this means that inputs should precisely match the ewes’ and lambs’ needs throughout pregnancy, lambing and growth to weaning.
For shepherds, this means managing our flocks for peak health. Ensuring that they receive appropriate treatments and nutrition at every stage of the breeding cycle will raise the likelihood of each ewe conceiving and rearing a pair of healthy lambs. At the same time, it’s the shepherd’s job to make sure that the ewe utilises the optimal level of resources to achieve this – no more, no less. In this way, every viable lamb will get the very best start in life, and at the same time will create a very light carbon hoof print!
Breeding from ewe lambs
This is an obvious way to reduce the flock’s environmental impact, as it means the ewes become productive at an early age, rather than spending their first year as consumers of resources. However, there can be problems with mating ewe lambs: even a well-grown lamb will only be around 75% of her mature weight at tupping and the cost to her of producing lambs will likely reduce her future growth potential. Ewe lambs will be less prolific, probably producing only a single lamb and many will fail to conceive – and finally, ewe lambs tend to have more lambing problems and may subsequently make poor mothers.
It’s almost impossible to stress strongly enough the importance of maintaining the ewes’ correct body condition throughout her pregnancy, and checking on a weekly basis will enable you to adjust feeding accordingly. Not only does having the ideal Body Condition Score determine her conception rate, but it also affects early-stage placental development, the ease with which she will give birth, the lambs’ birth weights (a critical factor for survival), their ability to be quickly up and sucking, the quality of the ewe’s colostrum at birth and her subsequent ability to nurture the growing lambs. Neither thin nor fat ewes make good mothers!
It’s been estimated that more than 60% of lamb losses are due to conditions that develop during pregnancy, rather than at actual lambing.
There are a number of factors that affect ewe condition, besides the quality of grazing or supplementary feeding, and these become critical in the last eight weeks of her pregnancy when the lambs put on a growth spurt. Any unexplained loss of condition in the ewe at this stage needs urgent investigation and remedial action.
Conditions that affect ewes & compromise lamb survival include:
- Parasitic worms and Liver fluke – a mature, fit ewe should have a well-developed immunity to gut worms, but will remain susceptible to liver fluke. An affected ewe will become thin, have pale mucous membranes and may develop a swelling under the jaw; your vet can carry out a simple blood test and prescribe a suitable flukicide for the specific stage of disease.
- Infectious disease – there are a number of infectious diseases that will cause a ewe to either abort her lambs during pregnancy, or give birth to dead or small weakly lambs; these include Toxoplasmosis, Enzootic abortion, Listeriosis and – since 2012, Schmallenberg Disease. Implementing a risk-based vaccination programme in consultation with your vet is an obvious and cost-effective way of increasing lamb survival, and should be a part of every shepherd’s flock health planning.
- Lameness – painful feet prevent the ewe from grazing, and she may be pushed away from the trough by stronger ewes, so treat lameness promptly. This will also prevent the spread of infection within the flock.
- Trace element deficiency – many soils, and consequently grassland, are deficient in some trace elements, which are vital for ewe fertility and lamb survival. Random supplementation with mineral licks and buckets may help, but at considerable cost! Have your soil and forage analysed to pinpoint shortfalls that you can then target with boluses. These are delivered orally, directly into the rumen and have a slow release, long-lasting effect.
- Pasturella & Clostridial diseases – annual vaccination of ewe 4-6 weeks before lambing will protect her lambs from these diseases for their first few weeks.
If you’ve had your ewes pregnancy scanned, you’ll be able to feed according to the foetal load each is carrying, ensuring that single-bearing ewes aren’t overfed and ewes carrying triplets are given preferential treatment as lambing time approaches. If a ewe has been undernourished during the last 8 weeks of pregnancy, her lambs may be born small and weakly, which will compromise their ability to stand and suck. Equally, if she is overweight at the time of birth, her lambs may be oversized. This can lead to lambing difficulties and a stressful birth, resulting in an exhausted ewe reluctant to feed and nurture her lambs.
Both thin and overfat ewes can suffer from a range of metabolic conditions at or around lambing, and emergency action is required to save the ewe and her lambs.
Pregnancy Toxaemia (‘Twin Lamb Disease’)
The ewe may appear blind, is likely to be down and not eating, and may froth at the mouth. The condition causes her own fat reserves to metabolise in the liver (‘ketosis’), causing blood poisoning that will kill the ewe and her unborn lambs unless prompt action is taken. The ewe needs energy in a form she can immediately metabolise, such as a course of intravenous glucose injections administered by your vet. Alternatively, you can administer glucose (glycerol, Propylene Glycol or ‘Ketol’) orally, which is quickly absorbed and rapidly broken down in the liver to provide the energy the ewe urgently needs. Treatment is intensive with an initial dose of 60-100ml, repeated every 4-6 hours. The ewe should quickly show signs of recovery, such as renewed interest in food, if not, there may be other factors involved, such as Hypocalcaemia.
Hypocalcaemia (‘Milk Fever’)
Can be triggered by stress; even simple things like bad weather or overcrowding in the lambing shed can trigger a reaction that interferes with her normal metabolism – in this case leading to low blood calcium. The symptoms are often difficult to tell apart from Twin Lamb Disease, so it’s usual to treat as though both conditions are present, and again, speed is of the essence. To replace the calcium deficit, use a proprietary calcium and dextrose mixture. Warm the solution to body temperature, and inject a large dose (50-80ml) subcutaneously (under the skin, as opposed to into the muscle) split across three or four sites. Gently massage the areas to help spread the fluid and aid absorption into the blood stream. The ewe should respond to this treatment within 30 minutes.
Hypomagnesaemia (‘Grass Staggers’)
Watch for this during the first 4-6 weeks after lambing, although it can occur before lambing. Fast-growing spring grass is often low in magnesium, resulting in low blood magnesium in the ewe, particularly one feeding two or more lambs. The ewe will be fidgety and restless, and may walk with a staggering gait. Untreated, she will decline rapidly, with convulsions, leading to death in a few hours, so always treat these symptoms as an emergency. Treatment is a large dose of magnesium sulphate solution (warmed to blood temperature and injected subcutaneously at 3-4 different sites). This solution will often also contain calcium, which is useful as there may also be an element of Hypocalcaemia involved. You can take steps to prevent ‘staggers’ by soil analysis and top-dressing your paddocks to correct mineral imbalances.
Each of these diseases is preventable through correct nutrition and good husbandry, and if spotted early enough, can be successfully treated. Meanwhile, it’s a good idea to stock up on treatments well in advance of lambing.
Lamb Birthweight and Vigour
Another key factor in lamb survival is birthweight, which again is determined by the ewe’s condition! For an average lowland ewe, her lambs should ideally each weigh 5-7kgs for a single, 5–6kgs for twins and around 4kgs for triplets – these will be vigorous lambs that will be up on their feet and sucking quickly after birth. The sooner the lamb has its first feed from its dam, the better its chance of survival. The ewe’s first milk – her colostrum, is rich in nutrients and fats that will keep the lamb warm on all but the coldest nights, and also carries antibodies against many diseases that kill small lambs.
Research has confirmed that ram lambs are behaviourally slower at birth than their sisters – they take longer to stand and suck than ewe lambs! So keep a close eye on ram lambs after they’re born, and make sure they get a good drink soon after birth to improve their chances of survival. Although once they get the hang of things they generally grow faster and bigger than their sisters, this initial slowness puts them at risk during their first critical hours of life.
It’s the shepherd’s job ensure that every lamb, and especially the slow or dopey ones, receives vital colostrum as soon as possible after birth. One of the most valuable of all shepherding skills is knowing how to feed a reluctant lamb by stomach tube – it’s a lifesaver for these slow lambs. So, no matter how late the lamb is born, never go to bed before all the lambs’ tummies are full – then you’ll be a step closer towards having a productive, carbon-neutral flock!
This article was originally written by Carole Youngs for
Practical Sheep, Goats & Alpacas Magazine.