Fit silage to animals’ needs for best results

The time has come to start altering our silage making to fit the animals needs, not the facilities on farm, says Dave Davies, independent advisor for The Silage Advisory Centre (SilAC)

Livestock producers need to give more thought to the silage nutrient content they require at harvest time to ensure they meet the needs of different stock types they will be feeding over winter.

It is during the weeks before cutting that this should be assessed, but all too often, the weather is right, the clamp is prepared and all the silage is harvested on that one day. Then the winter comes and the silage is not of the correct nutrient value for all the stock on the farm, and the problems begin. This can either be higher feed bills, poorer animal performance or more health and welfare problems.

Suckler cow, beef finishing farms

One good example of this is on a suckler cow, beef finishing farm. Often these units only have one silage clamp, however not making silages with two nutrient contents can be a very costly mistake.

Research conducted at Hillsborough, Northern Ireland, fed grass silage prepared with two different D-values and examined the effect of silage digestibility on live weight gain in finishing beef animals. The grass was harvested either at 73% D-value or 59% D-value. The higher D-value silage gave a growth rate of 1.10 kg daily live weight gain whereas the poorer D-value silage only enabled a growth rate of 0.78 kg live weight gain. That is worth 0.32 kg/d extra. However, if we consider the dry suckler cow the high digestible silage is likely to cause problems associated with over fat cows and all the additional problems at calving and vet costs. So the lower D-value silage would be ideal.

Dairy units

Another example is with the dairy unit. Often the dry cows get the silage from the top or sides of the clamp that has a higher risk of problems associated with less than perfect storage and the milking cows feed from the rest of the clamp.

If feeding silage to dry cows, it needs to be of low digestibility, high in fibre with a long chop and of high dry matter but with a very good fermentation quality to improve palatability but most importantly low in potassium. Baled silage would enable specific fields that had not been fertilized with potassium to be harvested just for the dry cows.

Targeting silage

There are many costs associated with not having the correct silage for the stock you are feeding. In the suckler cow/beef finishing farm case, making the silage meet the requirements of cow’s result in a much greater bought in feed cost for growing and finishing stock. On the dairy farm, the incorrect feeding of dry cows not only has the potential to cost in terms of reduced milk yield in the subsequent lactation, but can have significant costs associated with poor health and fertility.

So the time has come to start altering our silage making to fit the animals needs, not the facilities on farm, and if you only have one silage pit mixing and matching production between clamp and bales is likely to be the most economic way of producing silages with different nutrient contents to better match the nutrient requirements of the different classes of animals on your farm.

The benefit of bales

Many farmers however are put off baled silage because at first glance bales are seen as more costly to make than clamp silage.

However, to obtain a true picture of costs we need to cost the systems in terms of tonnes of silage dry matter fed in relation to the tonnes of fresh matter harvested. It is true harvesting costs can be somewhere near £100/ha more for baled silage than clamp. However the losses of silage DM between harvesting and feed-out are significantly lower in baled silage than clamp.

In a study at Institute of Grassland and Environmental Research (now Institute of Biological, Environment and Rural Sciences) the losses for clamp were 17.7% compared to 11.7% for baled silage. Once these losses have been taken into account the cost a tonne of DM of silage fed comes out at £41.20 for a clamp compared to £51.20 for a bale. These figures do not take into account the storage facility costs. These are highly variable from farm to farm, but for a bale these are generally much lower at about £1.50 /tonne DM compared to £18.00 /tonne DM in a clamp. This brings the costs for the two systems to more or less the same.

However, if you are at the point of investing in a new silage clamp then bales become a much more attractive proposition not only in terms of flexibility but also economics.

Dr Davies is also director of Silage Solutions

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