Lambing 5 - The Growing Lamb
Part 5 of a series of 5 articles:
Once the ewes and lambs are well “mothered up”, indoor lambing flocks can be turned out into a sheltered paddock, preferably one that hasn’t carried lambs the previous year. The ewes’ acquired resistance to internal parasites is reduced by the stress of lambing time, causing them to shed an increased number of worm eggs. To prevent contamination of the turnout pasture, and to protect the young lambs from being exposed to high levels of internal parasites, ewes are usually drenched at turnout and it’s now recommended to use a wormer containing ‘Moxidectin’ as this has a persistent effect, meaning longer-lasting protection for the lambs.
If the weather’s cold, or wet and windy try to provide some simple shelter for the lambs – straw bales are effective, as are thick hedges and mature trees. Lambs depend solely on their mothers for nutrition during their first 3 weeks or so – they may nibble a bit of grass, but don’t eat significant quantities at this age, so watch out for mis-mothering – ‘tucked-up’ hungry looking lambs can rapidly become hypothermic if they’re not quickly reunited with their mothers.
Continue to feed ewes at a ‘stepped-down’ rate, monitor their condition scores and provide a mineral bucket if you’ve identified deficiencies in your forage, and check the water trough at least twice a day. A lactating ewe needs up to 5 litres of water a day, so make sure there’s a good supply of clean water at all times.
Lambs can be offered ‘creep feed’ from 2-3 weeks of age, not only will supplementary feeding provide additional vitamins and minerals that may be lacking in the pasture, but lambs convert feed to muscle very efficiently at this age, so the cost of the feed will easily be made up for by increased growth rates. Use small pellets or a coarse mix that have been specially formulated for lambs, but don’t overdo the creep-feed as too much can cause acidosis and – in ram lambs or wethers – stones (urinary calculi) can develop that block the urethra.
Ewe’s milk production peaks at around 3-4 weeks, when the lambs are totally dependent on the ewe for nourishment, then slowly wanes as the lambs derive more of their feed requirement from pasture. By 6 weeks they will be much less reliant on the ewe’s milk, and at this stage, ewes no longer need supplemental feeding.
One of the greatest threats to newly turned-out lambs in spring is the gut parasite Nematodirus battus, which can have a devastating effect on young lambs. The larvae can survive the hardest winter encysted in the ground, then hatch in vast numbers during the first warm spell in spring. The early spring and warm temperatures indicate that the disease is already active in most areas of the UK. Typically, it affects lambs when they start grazing a significant amount of grass at between 6-12 weeks old. Ewes will not show any signs of ill health, but in young lambs it causes acute black watery diarrhoea (scouring), abdominal pain, dehydration, and loss of condition – and can quickly lead to death.
- If possible, turn lambs out onto ‘clean’ pastures that did not carry lambs in the previous year.
- At the early larval stage, the presence of the parasite can’t be detected by faecal egg counts (FECs), so at the first signs, drench all the lambs
- Take great care when drenching lambs as it’s easy to damage their mouths – use a small drench gun nozzle designed for lambs and don’t rush the process
- The choice of wormer is critical as in some areas resistance has been identified to the white, BZ group wormers, which have usually been recommended for this parasite, so your vet may recommend using an Albendazole or Ricobendazole product. If in any doubt, check with your vet first, who will also be able to tell you when the risk is highest in your area
- Affected lambs may need repeated anthelmintic drenching, and those affected will take time to regain lost weight
- To complicate matters, the symptoms are almost indistinguishable from those caused by Coccidiosis, so if lambs don’t quickly respond to anthelmintic treatment, consider drenching the whole group of lambs with a coccidiostat
- If possible, always avoid putting lambs on the same ‘nursery pasture’ year after year, as this encourages the build-up of these parasites
The level of pasture-born worms peaks in the summer, so carry out regular faecal egg counts and treat lambs promptly when the threat is high.
The protection from their mother’s colostrum against the Clostridial diseases and Pasturella will be waning by the age of about 6 weeks, and the lambs should now be vaccinated against these killer-diseases. This first injection will need to be repeated in a further 4-6 weeks to give full protection, and lambs that are being retained in your flock will then be given an annual booster.
This year’s warm spring has already caused cases of flystrike in mid-April, and as spring progresses and the blowfly population increases, all sheep are in danger of flystrike, especially any lambs that are scouring. ‘Pour-on’ treatments will protect the whole flock, but make sure you still check the flock twice daily, and choose your product carefully: especially check the product’s meat withdrawal period for lambs intended for slaughter, as they can be lengthy for some products.
As the lambs grow you’ll need to permanently identify them. The current rules and regulations regarding individual electronic identification (EID) of sheep are very strict:
- Tag within 6-9 months (6 months if kept housed overnight) or before they leave the holding of birth if sooner.
- Breeding animals (kept or sold) - two identifiers must be used (for sheep, this must include one EID - Electronic Identification). If your lambs are pedigree, check with your Breed Society for any special requirements.
- Animals for slaughter within 12 months - use a single ear tag (showing only your flock/herd mark) - from 2015, this must be an EID for sheep.
- For animals over 12 months, the second identifier can be a tattoo, pastern (leg band) or black ear tag instead of another EID ear tag. The use of some of these identifiers can prohibit export.
- If you lose a tag / identifier (or an EID becomes unreadable), it must be replaced within 28 days and recorded. If the animal is not on its holding of birth, it must be replaced with a red or black identifier - see the DEFRA website for details of replacement identifiers.
If you weighed your lambs at or soon after birth, by weighing again at 8 weeks old and comparing with the birth weights, you’ll get a good idea of their inherent growth rate. This is a basic form of performance recording and you’ll find it invaluable when selecting the best stock for future breeding.
Once the lambs reach the age of 12 weeks the ewes’ milk production is nearing its end, and the lambs will gain nearly all their nutrition from grass, so it’s vital to ensure grass is managed to supply this need. There are a number of factors to take into account when planning to wean the lambs:
- Firstly, the ewe must have plenty of time to enable her to return to good condition for next season’s tupping – at least 2 months
- Lambs should be weaned onto ‘clean’ pasture with a sward height between 6-8cm
- It’s less stressful to remove the ewes and leave the lambs in a familiar paddock
- Put ewes onto poorer pasture so that milk production ends quickly – this helps to prevent mastitis
- Ewes and lambs should preferably be out of one another’s earshot to lessen stress
Weaning is quite stressful for lambs and if the pasture is poor they will lose condition, so if they are close to their slaughter weight, consider leaving them with the ewes for up to 14 weeks. Check the ewe’s body condition before making your decision; if she’s in poor condition it will do neither her nor her lambs any good, and could be detrimental to her chances of rearing next year’s lambs successfully. And do remember, if you haven’t castrated the ram lambs, they will be reaching sexual maturity by about 5 months, so will need to be managed separately from the adult ewes and ewe lambs.
Now that the lambs have grown on and can live independently from their mothers, it’s time to assess them and decide their future. Depending on your future plans, you can separate the lambs into 4 categories:
- Slaughter lambs – these will be ‘finished’ to the correct weight and condition for the breed, and either sold as ‘fat lambs’ at market, or taken to the abattoir for slaughter, butchering and private sale
- Store lambs – these are lambs that are ultimately destined for slaughter, but by the end of the grazing season still need further time to achieve target weight. Unless you have plenty of good grazing to bring them on, take them to market and sell as ‘stores’ to a farmer who has plenty of grazing to ‘finish’ them
- Replacement ewes – inevitably, in most years you’ll need to replace some of the ewes in your breeding flock, and breeding your own replacements means you won’t have to buy in stock (but keep good records of which tups you use to avoid in-breeding)
- Breeding rams – breeding and raising stock rams is a highly specialised enterprise; buyers will only consider the very best examples of the breed, and increasingly may expect to buy Performance Recorded rams.
Handle the lambs frequently so that you can judge when they have enough meat cover, but don’t allow them to get overfat. If you have access to a weigh crate, weigh the lambs at regular intervals; for lowland breeds aim for a liveweight of around 42kg to produce a carcass weight of around 18kg.
Inevitably, a mix of emotions will accompany your first trip to market or to the abattoir; but knowing that your lambs have had the benefit of your knowledgeable care and attention throughout their lives should be a source of pride.
More information on caring for your flock during the breeding season can be found on “The Breeding Flock” DVD.
Written by Carole Youngs of The Smallholder Series.