Preparing lambs for weaning is extremely important to ensure they do not go backwards in terms of growth and health once milk feeding is suddenly removed.
Milk replacer of course will be the lambs main feed source for the first few weeks; however, they should be provided with fresh creep, clean water and forage such as straw to nibble on from the first week of life. Although they may not consume very much, it should be available to them so they are familiar with it from early on and younger lambs will learn from their older pen mates.
Weaning is a very stressful time for lambs and often there can be several barriers that get in the way of successful finishing that rearers should be aware of and avoid these pitfalls where possible.
The weaning process should be as stress free as possible and limits should be put on the number of changes taking place around this period. Stress can have a negative impact on the lambs’ immune system leaving them less robust to fight disease at this point. It is sometimes common that once the lambs are consuming a minimum of 200g/head/day of concentrates for three consecutive days they should be ready for weaning. Abrupt weaning off milk is often the best way to wean as prolonging the process can sometimes lead to bloat.
Quite often pet lambs reared on shine ewe-reka ad-libitum can outperform their siblings which are fed on the ewe. There are several reasons why ewes can drop in their milk supply such as diseases presenting e.g., Johnes or perhaps they get burdened by parasites or lameness and the list goes on.
Having a health plan in place to help prevent diseases which are likely to occur is a good place to start. If we think about vaccinations such as clostridia in particular because young lambs are prone to this disease especially when under pressure around weaning time. Timing the vaccine correctly is also vital because a stressed animal will not respond well to being vaccinated as their immune system is already impacted.
- Weaning should only happen when lambs are consuming adequate concentrates
- Better growth, feed efficiency and carcass growth when finished on ad-lib concentrate diet
- Avoid any other minor/major changes around weaning
- Weigh and monitor DLWG regularly
- Plan timely vaccinations and doses
- Have a health plan in place
- Conduct faecal egg counts, blood samples
Regular faecal egg count sampling can be a beneficial option to identify the worm burden levels within the lambs. A high egg count is considered >700-800 worms per gram. Warm and wet conditions can cause very sudden changes in worm burden so it is not a case of sampling on a one-off occasion due to their 3-week life cycles. Anthelmintic resistance is something else to be aware of when selecting the correct worm dose for the lambs. This is something to measure, monitor and manage with your local vet.
Coccidiosis is a common parasite known to affect young lambs post weaning, it presents itself as diarrhoea containing mucus/blood and often lambs appear dull and lose weight rapidly causing prolonged gut damage. It is a costly disease as it effects lamb health and performance. Oocysts can often remain in the environment from previous years or ewes shed oocysts on to pasture or bedding when housed.
Monitoring lamb performance through weighing and investigating any lambs that aren’t meeting their targets is essential to spot a problem early. Lambs at around 8 weeks old should have an average daily live weight gain of >250g per day. For example, a birthweight of 3kg for triplet lamb selected to be artificially reared gaining 250g/day – assuming the lambs are killed at 21kg deadweight (at a kill out percentage of 50%) will take 156 days to finish and reach their target weight. However, some lambs fed ad-lib have the potential to achieve >400g/head per day which would speed up the finishing process and post weaning can be intensively fed indoors on concentrates and forage. Recent trial work (Claffey et al., 2018) showed lambs fed ad – lib concentrate diets versus lambs fed 50% concentrate: 50% forage, or forage ad libitum had greater average daily liveweight gain, feed conversion rates and higher carcass weight. Therefore, ad-lib concentrate feeding has its advantages when aiming to finish the lambs early and achieve the best price.
Urinary calculi is something to be mindful of in male lambs. It can occur when stones (which are usually made up of phosphate salts) block the urinary tract and prevent urination. It is important to ensure the feeding ration contains a calcium to phosphorus ratio of at least 2:1. Avoid inclusion of additional magnesium or phosphorus to the concentrate diet. Ammonium chloride (0.5%) can be added to help acidify the urine and prevent the formation of calculi. Roughage will also aid with salivation and rumination which will increase the amount of phosphate excreted in the urine.
Hygiene should be top notch and cleaning out water troughs regularly is important. History of previous year problems should be highlighted and avoided where possible. In addition, where possible younger lambs should not be grazed behind older lambs and stocking density should be well managed to avoid poaching and tight grazing.
Every lambing season is different on the farm and when the lamb is weaned and finished is very much dependent on various factors. Weather being a significant factor, this year (2021) in Ireland it was a very cold Spring compared to usual with frosts still occurring overnight during the month of May. Therefore, grass growth was slow compared to other years, with this in mind it may be a better idea to intensively finish the lambs inside on concentrates and forage especially if lamb price is good. As well as this, a damp and warm year can also give rise to increased problems with nematodirus which can cause high levels of mortality and stunts growth on surviving lambs. Before the they can hatch, the eggs have to undergo a period of cold weather followed by warmer temperatures of 10°C or more. If these conditions occur over a short period of time, triggering a mass hatch, and it coincides with the time when lambs are starting to take in significant amounts of grass (>six weeks old), the result can be devastating.
Mineral deficiencies can also cause pitfalls in getting the lamb to where it needs to be on time. Cobalt, selenium and copper are three important minerals to ensure the lamb is thriving well and reaching their targets. Healthy lambs grow quicker and it is vital to optimise the health of lambs where possible. If weight gain is an issue and everything else appears to be in line it may be a good idea to obtain blood samples from the lambs to identify if they are lacking in a specific mineral or vitamin. CCN (cerebrocortical necrosis) is a severe brain condition in lambs post weaning and is often caused by changing their ration. The cause of CCN is a lack of Vitamin B1, this vitamin is produced by rumen microbes. There are different things which can alter the balance of rumen microbes such as severe changes in their diet and as a result the amount of vitamin B1 produced decreases and thus leads to CCN. To prevent this, it is necessary to make sure diet changes are very gradual to ensure a smooth transition.
In summary, we know that lambs are very vulnerable during weaning as it is stressful time for them (changing diet and perhaps their environment and pen mates) so avoiding stress by minimising as many changes where possible around this time allowing for a gradual transition will make it a lot easier for them to progress in their performance and health post weaning as opposed to going backwards and experiencing a growth check. Monitoring, measuring and managing the lambs correctly is vitally important to achieve successful finishing of lambs on time by helping them to meet their targets.