Careful management of triplet-bearing ewes is essential if they and their lambs are to survive. Ben Allott tells you how.
In many high performing crossbred flocks large numbers of triplets are becoming the unwanted symptom of reproductive success. Large losses of ewes and lambs are frustrating and there is often significant opportunity to improve performance.
What do we know about triplet bearing ewes and their lambs?
The ewe
At birth, the weight of the pregnant uterus, placenta, fluids and lambs is a huge 20-22kg!! The space the uterus takes up means that in the last two weeks of pregnancy, feed intake in triplet ewes declines. Despite higher energy requirements, under trial conditions it has been shown that triplet-bearing ewes cannot take in more feed than twin-bearing ewes. In late pregnancy triplet-bearing ewes have lower blood sugar levels and higher ketone levels than twin-bearing ewes. They are burning through more energy than they consume. They are running right on the edge of metabolic disease (sleepy sickness/milk fever). Triplet-bearing ewes suffer higher mortality rates than twins. More are lost to sleepy sickness, to milk fever, to becoming cast, and to bearings.
The lambs
Triplet lambs are born small, on average 65% the weight of a single. As a result, within the first few hours of birth triplet lambs have lower body temperatures, which are closely correlated with poorer survival. A triplet lamb is about twice as likely to die as a twin with the biggest killer of triplet-born lambs being a combination of starvation and exposure. When separated from the ewe by just 10m only 70% of triplet sets, compared with 91% of twins and 100% of singles, reunite within five minutes. Separated triplets do not find mum well.
So, what can you do about it?
Pre-lamb treatments
I am convinced that the stress induced by late pregnancy pre-lamb treatments is a large problem on many farms. Ewes are walked long distances, held on tight rations, yarded for long periods, placed under huge mob stress, then injected with vaccines that will induce an inflammatory response before again being walked long distances on empty stomachs. Do not do this in the last two weeks of pregnancy for any ewe! I would prefer you avoid doing this in the last four weeks of pregnancy. Get pre-lamb out of the way early, especially in triplets. Talk to your vet about suitable pre-lamb options. These ewes can then go back into a winter system with no yarding required before set-stocking.
Body condition score (BCS)
Mate ewes at BCS 3.0-3.5. Maintain this level and do not allow ewes to become overfat through the autumn or to lose BCS through the winter. Lamb ewes at BCS 3.0- 3.5. Ewes that lose weight in pregnancy are a problem group. Ewes that are excessively conditioned are equally problematic. Maintaining BCS requires you to know, budget for and allocate the true feed demand of the ewe.
Feed allocation
You cannot get the triplet ewe to eat enough feed to fully meet her requirements but you can ensure that your management does not restrict her feed intake further. Remember that triplets are right on a knife edge and the smallest restriction may tip them off. From scanning until a month before lambing do not graze triplets below 1000kgDM/ ha. Following this, triplet ewes in late pregnancy should never graze below 1200kgDM/ha (4cm), preferably higher. Do not for any reason restrict feed availability to triplet ewes in the last four weeks of pregnancy.
Shearing
Triplet ewes in heavy fleece get cast. Ewes in heavy fleece in late pregnancy get more bearings. Ewes in heavy fleece eat less feed in late pregnancy. In high performing cross bred flocks I personally advocate shearing ewes in mid-pregnancy (d50-d90) leading into scanning. Avoid pre-lamb shearing of multiple bearing ewes.
I am convinced that the stress induced by late pregnancy pre-lamb treatments is a large problem on many farms.
Diet changes
Triplet ewes are vulnerable to the consequences that diet changes may have on feed intake. I would encourage you to plan winter feeding to allow triplets to spend the last four weeks of pregnancy on a consistent diet that is similar to their set-stocking pasture type. This doesn’t mean you should set stock this early, but avoid changing their diet dramatically several weeks out from lambing.
Feeding supplements?
Grain or pellets can be useful in managing the increased feed demand of pregnant ewes. However, supplement feeding does not change the basic rule around grazing residuals. If you are feeding supplements to build covers and keep residuals in late pregnancy above 4cm then I am convinced of the benefit. If pasture is of good quality and residuals are above 4-5cm I am not convinced supplements will be of significant benefit to you. In many situations the practicalities of supplement feeding introduce mob pressures, mob stressors and significant disturbance that I am convinced is often detrimental to multiple bearing ewes.
Herb and clover stands?
Higher feed quality, improved protein supply, increased mineral supply, and improved feed harvesting characteristics are commonly mentioned as reasons we should lamb triplets onto herb and clover stands. These factors are all potentially beneficial but I am also often concerned by these crop paddocks having poor shelter, often being located in high disturbance/traffic locations, and the fact that high stocking rates are often required to keep on top of the rapidly growing feed.
Disturbance
A mis-mothered triplet is likely a dead lamb. Lamb triplets at low stocking rates – 5/ha – and lamb them in paddocks where there is minimal disturbance from the sound and sight of dogs, motorbikes and traffic and they are out of sight of other stock movements. Any stimulus that will cause the ewe to move away from her lambs, even temporarily, will have a high cost.
Shelter
One of the biggest killers of triplet lambs is exposure. Lamb triplets in paddocks with natural shelter distributed throughout the paddock. The shelter types available should allow ewes to find isolated shelter spots away from other ewes while they lamb. A single shelter belt that all ewes cram under is a recipe for mastitis, navel ill, and high rates of lamb and ewe wastage.
Slope
Triplet ewes on slopes get bearings, and steeper slopes are associated with higher mis-mothering losses in multiple lambs. In saying this, triplet ewes on flats do seem to love getting cast. I would go for low stocking rates on sheltered rolling to moderate hill country over higher stocking rates on exposed flats any day.
I have seen both intensive and hands-off systems work very well with triplet ewes. In every case though the key principles have been the same. Maintain BCS of 3.0-3.5, maintain sufficient grazing residuals to ensure ewes harvest enough feed, reduce all causes of stress in late pregnancy, and minimize the disturbance experienced by ewes through lambing.
- Ben Allott is a North Canterbury veterinarian.
