Lupin Feeding & Utilisation

Lupins provide a fully traceable substitute for imported Soya. There are now hundreds of UK farmers growing Lupins and discovering their excellent feeding qualities. Soya UK Ltd are at the forefront of Lupin crop development, and are constantly looking at optimising the use of Lupins in livestock systems.

The Nutritional Value of Lupins

  • There is a very distinct difference between the different types of Lupin and their feeding values. The Crude Protein (Dry Matter basis) of White Lupins and Yellow Lupins will often average from 36 - 40% (although Yellows are more variable). Blue Lupins will tend to be 31 - 35%. From this, it is obviously very important that we know which type of Lupin we are dealing with. Amazingly, many growers remain unaware of which type of Lupin they are growing, but if the crop is to be valued and fed with any degree of accuracy, Lupin type is the first question growers should consider (See table for a comparison of types).
  • The second thing the Lupin grower should do is have an analysis carried out. Analysis can be variable from lab to lab and some labs will quote on a dry matter basis, whilst other labs will provide an "as fed analysis" (38% C.P on a dry matter basis, is the same as 32.5% C. P. on an "as fed" basis). However, analysis is necessary to allow accurate formulation.
Lupin Type  Energy M.E.   (MJ/kg D.M)  Oil Content          Typical Crude Protein as a % of Dry Matter
WHITE15.010%36 - 40
YELLOW13.04%36 - 42
BLUE13.56%31 -35

From an energy point of view, Lupins generally tend to be high in energy, again with distinct variation between the different types. The reason for this variation is the different oil contents of the different types (see table above) and is another good reason that growers must know which type they are dealing with.

The significance of protein density

Protein density is of pivotal importance in feeding modern stock. If we wish to formulate a diet for stock at the lower end of the production scale (such as Suckler cows), a dietary protein level of 12% would be sufficient. Formulating a diet of 12% using silage at 10% and some peas or beans, would be no problem, but as we move up the productivity scale, the requirements for protein increase dramatically. Formulating rations based on the same forages of 12% grass silage, or worse, a 9% maize silage, means that we need high-density protein sources to balance the ration.

For example, a high-production Holstein dairy cow has a dietary protein requirement equivalent to 18-20% of her total diet when she is in early lactation, moving to 16% in mid-lactation. In order to balance this ration, the dairy farmer would traditionally have fed an 18% or 20% dairy concentrate in order to make up the protein shortfall. Any additional protein shortfall would also be compensated for by a normal loss in body condition during early lactation.

For the farmer trying to convert over to home-grown feedstuffs, the problem is that in order to make up this protein shortfall, you must use a dense protein source. In order to make an 18% ration using peas or beans at 25% CP, and silage at 12%, we would need to be include the peas at 47% of dry matter intake, and silage at 53%. Clearly, this level of inclusion is impossible, and a protein source denser than 25% is required in order to balance the ration. On this same farm, Lupins at 38% CP, could be used to make the 18% ration using Lupins at 23% of DM intake, and silage at 77% of DM intake. This is perfectly possible, would give a massive saving in concentrate costs, and allows the farmer to achieve his aim of self-sufficiency in home-grown feedstuffs.

Protein Degradability

Another advantage of Lupins, is the comparatively large amount of Digestible Undegraded Protein (DUP) which they contain in relation to their Effective Rumen Degradable Protein (ERDP). Of course, the ERDP content of Lupins is higher than that of peas, beans or rape meal, for example, however, this feature is less important, since ERDP is relatively cheap in it's various forms. DUP on the other hand, is valuable, and Lupins are relatively high in their DUP content. For example, in the case of high yielding stock, the DUP content of Lupins is double that of peas (See graph)

Graphic of Rumen degradability

Using Lupins as a Soya Replacement

Feeding trials from a variety of sources in Australia, USA and UK, have concluded that Lupins can be used as a direct replacement for soya meal. The table below shows that the dairy cows fed Lupin protein in a balanced diet actually performed slightly better from those who derived their protein from soya meal.

Response of dairy cows fed sweet white Lupins (day 22 to 140 postpartum)

Treatment    No.
Cows
Milk yield
(kg/day)
uncorrected
Milk yield
(kg/day)
3.5% fat corrected
Fat yield  
(%)
Fat yield  
(kg/day)
Protein
yield
(%)  
Protein
yield
(kg/day)
Dry Matter
intake
(kg/day)
100% Soya1127.327.5b3.70.973.00.8219.9
75% Soya
25% Lupin
1128.929.1ab3.71.033.00.8620.8
50% Soya
50% Lupin
1028.428.6ab3.61.012.90.8120.6
25% Soya
75% Lupin
1230.030.3a 3.71.082.90.8621.0
100% Lupin1028.328.8ab3.81.022.90.8220.4
SE 0.840.680.10.030.10.020.49

All means are covariantly adjusted. Treatment means with different subscripts are significantly different (P <.06). Source Putnam 1997

Practical Examples

  • Example 1
    A farmer has grass silage analysis done and Lupin silage analysis done. Grass silage is 12% C.P. and Lupin silage is 20% C.P. He has growing beef cattle that require a 14% C.P. diet and 16% during the "finishing" period. A mix of three parts grass silage to one part Lupin silage will give him a forage bas of 14%. Energy need may well be deficient if silage intakes are low, however some rolled barley and mineral could be fed to meet energy needs.

    During the finishing period, the farmer may choose a 50:50 mix of grass/Lupin silage, to bring the base up to 15%, however, more likely by feeding crimped or rolled Lupins at 40% C.P. at a rate of 1kg for every 20kg of the 3:1 silage mix, he will bring the total ration up from 14% to 16%.
  • Example 2
    A farmer is currently feeding an 18% concentrate at 4kg/Head/Day to his beef cattle, and wishes to replace this with home-grown white Lupins and barley. How much of each should he be using?
    4kg of 18% concentrate at 87% dry matter = 3.48kg dry matter containing 720g crude protein (at 207g/kg DM), and 43.5 Megajoules of energy (at ME of 12.5 MJ/kg DM).

    We assume his white Lupins are 15% moisture, contain CP at 380g/kg DM and an ME of 15.5 MJ/kg DM, and his barley is also 15% moisture with CP at 129g/kg CP and an ME of 13.3.
    1.5 kg of white Lupins at 85% DM = 1.275 kg DM containing 484g CP plus 19.76 MJ of energy.
    2.2 kg of barley at 85% DM = 1.87 kg DM containing 241g CP plus 24.87 MJ of energy.
    So, his 4kg concentrates is replaced by a 3.7kg mix containing 1.5kg white Lupin and 2.2kg of barley. He must feed mineral supplements to make up for the mineral content in the cake, however he has achieved his aim of moving to home-produced feed.

The financial implications of moving to home-grown Lupins

When concentrate prices are high, and milk prices to the producer are low, then milking from concentrates is difficult to justify. Where the Lupins and barley are home-grown, the low production cost of Lupins begins to make a big difference. With the opportunity cost of the land, variable costs, and average yields taken into account, the production cost of the Lupins will only be £58/tonne all-in. If we allow £50/tonne for the production costs of home-grown barley, then the cost of the 18% replacement ration is £52/tonne, instead of £138/tonne for 18% concentrates. (A saving of 62% on feed costs!).

What does this mean? In simple terms, a dairy farmer who is currently growing other break crops can switch into Lupins and save up to 62% in feed costs. We also must accept that it is a lot easier to write this down than it is to do it in practice, however the potential cash savings for UK stock farmers could be very significant, before we even begin to value the traceability and non-GM benefits.