Choosing concentrates this winter
Michael Garvey, Dairying Development Adviser, C.A.F.R.E.
Selecting the correct concentrate to complement winter forage is key to maximising performance for your herd. Once you have established the quality of your silage by chemical analysis select a suitable ration to balance the silage quality available.
The concentrate to be fed to a high yielding dairy cow over the winter should have a good energy density, a balance of starch, digestible fibre, protected fats/oils and sugar ingredients, plus a balance of rumen degradable and undegradable protein sources.
Table 1 gives the overall average of first and second cut silage analysed through Hillsborough Feeding information System based at AFBI Hillsborough.
| 2006 overall average | |||
|---|---|---|---|
| First Cut | Second Cut | Comments | |
| Dry matter (%) | 28.0 | 27.2 | Good |
| Protein (% DM) | 12.3 | 12.8 | Satisfactory |
| Metabolisable energy (MJ/KG DM) | 10.7 | 10.4 | Average |
| D-value (% DM) | 67.1 | 64.7 | Average |
| Intake Potential (G DM/KG W0.75) |
In general silage available on farms this winter should be dry, with average energy and protein levels.
Specifically - for a 600 kilo cow, maintaining condition, yielding 32 litres of milk, SAC Feedbyte recommends 10 kilos of concentrate (Table 2) fed with approx 40 kilos of fresh first cut .10.5 kilos of concentrate are required when fed a similar amount of second cut silage.
Table 2 : Concentrate Specification
| ME (MJ per kg DM) | 13.5 - 13.8 |
| Protein% (As fed) | 20 |
| Fibre % | 8 - 11 |
| Starch % | 25 - 35 |
Where analysis shows that the available forage has low intake characteristics, for example, either one or all of the following low silage intake potential (<85), low dry matter(<18%), or low pH (<3.8), the concentrate composition (Table 3) becomes more critical.
Table 3: Typical Concentrate Composition
| Category | Ingredient | % Inclusion |
|---|---|---|
| Cereals | Barley / wheat / maize | 35 - 45 |
| Digestible fibre | Citrus pulp / soya hulls / sugar beet pulp | 15 - 25 |
| Soya / protein products | Soya / sopralin / rape seed | 18 - 25 |
| Cereal by-products | Distillers / gluten | 15 - 20 |
| Fats | Megalac / C16 fat matrix | 3 - 4 |
| Minerals | Protected minerals | 2 - 3 |
A low silage intake results in reduced forage to concentrate ratio. If forage dry matter intake is less than 40 percent of the total, there is an increased risk of rumen disorders - leading to acidosis and displaced abomasums in high yielding cows. In such situations, concentrate cereal content (i.e. barley, wheat, maize) should be reduced to around 20 percent and digestible fibre contents (i.e. citrus pulp, soya hulls or sugar beet pulp) should be increased to around 2530 percent.
Analyse your silage now. Use the results to select a concentrate to balance the silage quality available. Contact your local Dairying Development Adviser to arrange your sample and maximise its potential on your farm this winter.