There are many advantages to feeding good-quality forages in the form of a total mixed ration (TMR).
Not only does it allow concentrates to be virtually removed from the diet of pregnant ewes, but it can be the best and most effective way of feeding ewes because it gives them exactly the right diet, providing it is correctly balanced.
Independent sheep consultant Lesley Stubbings believes more farmers should consider feeding TMR.
“By improving grassland management more farmers are making high-quality big bale silage, therefore TMR is something they should at least be looking at as it removes reliance on concentrates and ewes perform better.
“Even if farmers can’t afford a full TMR, the principle of optimising the contribution from forage with minimal supplementation is one that they can aim for.”
Below she outlines some of the key considerations.
Why feed TMR?
There are many advantages, not least that ewes have been shown to perform better on this diet and it is a cheaper feed than concentrates.
Ms Stubbings says sheep farmers have been wrongly conditioned to believe that ewes eat less in late pregnancy.
“They don’t like the idea of feeding forage topped up with a small amount of supplements so they fill [sheep] up with concentrates instead.’’
By providing a constant diet throughout the day there are none of the large shifts in rumen pH associated with feeding concentrates on their own and the ration can be formulated to meet the needs of ewes at different stages of their pregnancy, with minimal changes in the diet.
It is essential that forages are analysed and advice sought on balancing these.
Nutritional value can vary widely, even between batches made in the same year, therefore each batch needs to be tested and the quantity of each calculated.
An analysis undertaken by a reputable laboratory will indicate how much additional feed is needed to fill any nutritional gaps in the forage.
Discuss the analysis with a nutritionist.
Silage quality must be good
“There is no room for getting it wrong, forages have to be good quality or you will have to supplement with concentrates.’’
Forages at 11ME or higher and 16-17% protein will take the ewes all the way through to lambing and only a protein source and minerals need to be added.What you supplement with depends on the silage quality – feeds such as rolled cereals, maize meal and molasses can be used.
“Perhaps 250g of soya/ewe/day or finely smashed up beans two to three weeks before lambing for triplets and twins and 100-150g for singles for about 10 days,’’ Ms Stubbings recommends.
Include a general sheep mineral that is not too high in calcium but with a high level of vitamin E (>4,000iu) at 20-25g/head/day, to balance up the forage.
If silage is too wet – less than 25% DM – a ewe will find it difficult to eat enough to meet her needs.When this is the case, more supplementation is required to compensate.
This is also the case with very acidic or butyric silages, both of which will affect palatability and restrict how much a ewe eats.
Stack bales according to quality
Know the quality of your forages and organise them accordingly so that higher-quality forages can be accessed when needed.
“The most frustrating thing I hear from farmers is that they have good-quality silage but that they can’t get at it,’’ says Ms Stubbings.
“Get organised at harvesting. TMR is very simple for the sheep but the trick is how you organise it – it is important to get the logistics right.’’
She recommends matching the silage quality to the pregnancy stage and using higher qualities in the later stages.
What infrastructure and machinery do I need?
As well as a diet feeder, farmers considering TMR must have a building suitable for this type of feeding – one that has feed passages and can be accessed with a machine.
It is the cost of these that puts some farmers off, Ms Stubbings admits.
“TMR is a cheaper feed than concentrates, but you do have to factor in the cost of machinery and infrastructure, which is the bit you do have to balance it with.
“The feed wagon, handling the silage and feeding it out puts people off and does prevent a lot of people from going down the TMR route.’’
If feeding big-bale silage, the machine must be capable of dealing with this – it must have sufficient power, knives and auger strength.
When making big bales, aim to at least double chop the grass, as long material will reduce intakes – a chop length of 3-5cm is ideal.
How often should I top up the TMR?
Ewes must have 24-hour access or there will be problems with crowding and bullying at the barrier at feeding out.
Intakes can be estimated initially but carefully monitor actual intakes and be prepared to adjust if required.
“If you are doing it correctly, when you walk into a shed some ewes will be lying down cudding, others feeding and there will be no pushing when the machine comes in.’’
A good mix is required and any additions must be small enough to avoid ewes picking out the bits they like best.
How do the costs stack up against root crops?
Home-grown, high-quality, conserved forages are the most economic feeds for housed sheep, but TMR costs are generally comparable to root crops such as swedes.
Ms Stubbings says cost per ewe depends on how root crops and silages are costed.
“Everyone has got to do their own sums and you have to cost the silage according to what it costs you to make, per unit of energy poor silage will cost more than good-quality silage.’’
Swedes deliver an energy value of 12-13 MJ/kg DM compared to high-quality silage at 11-11.5MJ/Kg DM, but the protein levels in swedes are lower – 10-11% – so this needs to be balanced.
Advantages of TMR:
- A wide variety of feedstuffs can be used
- No sorting of feeds
- Ration is nutritionally balanced
- No separate feeding of vitamins, minerals, additives or grain
- Reduced digestive upsets compared to concentrates.
Disadvantages of TMR:
- Cost of equipment
- special attention required for ration formulation feed analyses and silage moisture.
Ben Anthony and Diana Fairclough were so convinced by the benefits of feeding their pregnant ewes TMR that they built a shed to facilitate this system and invested in a diet feeder.
While some sceptics say a TMR diet will not encourage high enough intakes of forage, they say optimum intakes can be achieved.
This approach allows them to get the most out of forage.
“Our aim is to grow and feed as much forage as possible and to achieve that we feel TMR is the best option,” says Mr Anthony, of Frowen, near Login, Carmarthenshire.
There is a range of grass types on the farm – from permanent pasture to new red clover leys – and the TMR diets are formulated according to the forage being used.All forages are analysed.
“Once we know the analyses of the forages, we can work out what we are going to feed in terms of the TMR diet and when we are going to feed it during the time the flock is housed,’’ says Ms Fairclough.
As the ewes come into the shed they are sorted into groups according to the number of lambs they are carrying, their condition is scored and they are penned accordingly.
A TMR ration of 3.4kg of silage is fed in a ration of 40% soya, 30% rape, 15% maize distillers and 15% ground maize, with twins receiving 250g at the point of lambing, singles 100g and triplets 300g.
Minerals are also added.
The silage at Frowen analysed at 37.2% DM, 15.1% protein and 11.3 MJ/kg ME.