So, your scanning results are in, and you are relatively happy with them. This has come from you making the right decisions and having ideal conditions up to this point. Now you are presented with a new challenge. Improve lambing by maximising the survival of ewes and lambs throughout pregnancy, and get the lambs weaned off in top condition and ready to stack on weight.
- Scanning rates set the ceiling for the enterprise, from scanning onwards success is measured in weaning rate and weaning weight
- Poor nutrition during pregnancy is commonly responsible for lower performance of newborn lambs
- A condition score change after day 90 of pregnancy can alter lamb birth weight by 0.5 kg
- Nutritional requirements rise significantly from 4 weeks pre-lambing until 6 weeks post-lambing
- Requirements of twin bearing ewes are almost double that of singles
Improve lambing by increasing lamb survival
According to MLA’s Making More From Sheep program, “poor survival of newborn lambs is a major source of lost productivity in breeding enterprises, where lambing percentages of 110–130% born can result in a marking percentage of 70–90%. Most of these losses are associated with poor ewe nutrition during pregnancy.”
Ewe nutrition is key to increasing lamb survival
In many cases this poor nutrition stems from ewes not receiving enough protein, energy and essential minerals, vitamins and trace elements to fulfil the increasing requirements of pregnancy. It is recommended for ewes to maintain a stable condition score (around score 3 to 3.5) for the duration of pregnancy. The nutritional requirements begin to rise slightly from day 40 onwards, with a significant increase from day 90 (scanning) until day 152 (lambing), especially in twin bearing ewes. A condition score change, either positive or negative, after day 90 can alter the lamb birth weight by 0.5 kg, so it is important for the ewe to have a rising plane of nutrition from day 90 onwards without over doing it (see fig 1).
So, what can you do to achieve a rising plane of nutrition and improve lambing by weaning more healthy lambs this year?
1. Use poorest feed first
Where feed availability may be limited throughout pregnancy, it is important to allocate the poorest feed to the ewes first, so you don’t have to rely on this feed later in the season when nutritional requirements are high. Interestingly, if ewes drop below condition score 3 in early pregnancy and regain that condition in late pregnancy, the effects are similar to maintaining a condition score of 3 throughout the whole pregnancy. In saying this, it is important to note that it will become more difficult to add condition to pregnant ewes as pregnancy progresses. Your best quality pasture should be saved for your lambing paddock.
2. Effective worm management throughout pregnancy
An easy way to improve lambing is by effectively managing parasites. Worm burdens can significantly increase the nutritional requirement of the ewe during pregnancy and can see the ewe drop below condition score 3 in late pregnancy, if not managed effectively. Use FEC’s and if a treatment is required, don’t leave it too late. The window for treatment closes in late pregnancy, as stress becomes a concern. Keep in mind that the ewe has a compromised immune system during pregnancy; so mild worm infections can quickly become a much larger problem.
3. Separate twin bearing ewes from the flock and feed grain
The nutritional requirements of twin bearing ewes are almost double those of singles. These ewes are also your high producing animals which, if managed well, will improve lambing results by producing two healthy lambs. The energy requirements for twin bearing ewes during late pregnancy will always outstrip availability, and if not supplemented with energy (grain) there is a likelihood that they may develop pregnancy toxaemia (twin lamb disease).
The trick to avoiding pregnancy toxaemia is to control the level of weight loss and energy depletion in ewes in late pregnancy by ensuring that energy consumption is as close to energy expenditure as possible. This can be achieved by grazing a high energy pasture (lush green pasture) and or offering a high energy supplement like grain from day 130 pre-lambing (begin feeding grain earlier on dry pasture or stubbles), until at least day 30 post-lambing (see fig 1). Grain supplementation will also boost post-lambing milk production and get the lambs off to a great start.
4. Check and maintain hoof health early
Around six weeks before lambing, the foetus begins to grow and develop rapidly. This extra weight (especially in twin bearing ewes) can put a significant amount of stress on the ewe and particularly her hooves. During dry conditions, ewes can handle the extra weight on the hoof and are more open to lying down when their feet get sore. In wet conditions, a combination of softening hooves and more time spent standing, due to the dislike of lying on wet ground, can cause feet to swell and develop lesions.
Maintaining hoof and foot health through trimming, feeding supplements with zinc and biotin (StockMins-Hoof n Horn), offering ewes dry areas to camp and foot bathing (if required and not too close to lambing), can reduce the incidence of hoof issues during lambing. It is important to get on top of hoof issues early and control lameness well before lambing.
5. Beware of lower feed intake during late pregnancy
In many cases in late pregnancy, especially in twin bearing ewes, the growing foetus’ and placenta can take up a large amount of room in the abdomen. This can squash the rumen and significantly reduce the ewe’s appetite. This reduction in feed intake at a key period of production can see energy levels decrease, bringing about pregnancy toxaemia. In this scenario, supplementary feeding with grain (on a rising plane up to 700g/hd/day on low energy pasture) can reduce the risks of pregtox by boosting ewe energy levels. Protein levels of feed are also important as they are the building blocks for growth and development. For single bearing ewes, grazing actively growing lush green pasture should be enough to support energy and protein requirements during lambing.
6. Manage mineral, vitamin and trace element requirements
During the 10-week period from late pregnancy to early lactation (4 weeks pre-lambing to 6 weeks post-lambing), the lamb is almost entirely dependent on the ewe to provide essential minerals, vitamins and trace elements for growth and development. When required by the lamb, the reserves of these minerals and trace elements stored within the ewe’s bones, organs (particularly the liver) and muscles are mobilised and are quickly expended, resulting in imbalances if not supplemented effectively.
To satisfy healthy bone development, calcium demands from the ewe peak when the lamb is ten days old. Producers can improve lambing by offering a balance of calcium, phosphorous and magnesium leading up to and after the period of peak demand, to replenish stores and prevent serious deficiencies. Similarly, trace elements and vitamins are essential for immune function, lamb growth and feed conversion while the ewe and lamb are at their most vulnerable.
A recent independent study showed that feeding ewes a complete mineral supplement, like StockMins-EweLamLac, from late pregnancy to early lactation significantly improved lambing, by boosting ewe and lamb performance during the lambing period (pre-lambing through to weaning). The study revealed that over a 14-week period (4 weeks pre-lambing, 6 weeks lambing and 4 weeks post-lambing), ewes supplemented with StockMins-EweLamLac HE achieved, on average, higher weaning rates (+3.3%), higher lamb weaning weights (+6.1kg) and better weight retention in ewes (+4.8kg), than those supplemented with a mix of Causmag®, lime and salt. See full results of trail via the link StockMins-EweLamLac HE Trial Results
So, what does this mean for you?
While positive scanning results are great to see and mark a strong start for a lambing enterprise, the true measurements of success are weaning rates and weaning weights. The ideal goal of any successful production system is to maximise the number of lambs weaned at the highest average weight in the shortest amount of time.
The steps discussed above have proven to improve lambing results by getting breeding ewes in the best possible condition to minimise pregnancy and lambing difficulties, and give newborn lambs the best start for a healthy life.
Causmag is a registered trademark of Causmag International. StockMins-EweLamLac is a product of AusFarm Nutrition Products 12 Blaxland Rd Wagga Wagga 2650.