Bad silage is costing farmers a lot of money

Late applications

High ammonia results can be the result of late fertiliser applications (ammonia reduces the fall in pH), insufficient wilt, inadequate fermentation (pH 4.4+) and secondary fermentation. Protein is particularly susceptible to degradation from inadequate pH (pH 4.4+) and forms ammonia, amines and amides.

This issue occurred in the poor grass silage meaning more protein is needed to supplement the ration and this was achieved through more soya/rape meal and some feed grade urea. Poor silages need more concentrate, fats and improved palatability and even then, cows will never perform as well as with a well digested high energy grass silage. I have applied both these forages to a typical farm situation based on 9,000-litre cows. The forage element was based on 25% maize silage poorer silage needs a palatability driver to encourage appetite and I have chosen 1.75kg of molasses (see Table 2).

Fermentable starch from caustic wheat and bypass protein from the soya/rape blend are also required to boost intake, while fat is needed to boost the energy density to sufficient levels. As a result, a 30-litre cow requires 10.85kg of concentrate to achieve production, whereas a cow fed the better silage requires 7.54kg. If we assumed for simplicity that these cows were housed all-year-round the additional feed cost would translate into £32,000, with a potential additional increase in £13,000 of improved milk yield if cows were fed a better grass silage (see Table 3).

Feed efficiency

The feed efficiency translated from 0.35kg/litre to 0.24kg/litre between both forages with a purchased feed cost saving of 3.19ppl. If we incorporated the forage cost there would be a 2.43ppl difference between the diets (12.13ppl for the poor forage and 9.7ppl for the better forage), this difference is less than the purchased feed cost because we are gaining more milk from forage and so must feed more forage per cow. The forage figures above were based on market costs, correct nutrient application and good farming practice both a poor and high-quality grass silage should cost in the region of £27.50/tonne, albeit a poorer forage maybe slightly cheaper due to some shortcuts. Significant figures include £247/hectare land rent, £9.53/tonne fertiliser and application cost and £1.67/t attributed to the cost of instalment of a silage clamp over 50 years.

We would expect a fouryear perennial grass ley to produce on average of 56t/ha grass silage across the year with at least 22t/ha of quality first cut grass silage taken before the second week of May. However, such figures are based on good fertiliser management, mowing at optimum sugars, sufficient grass wilting, significant compaction and attention to detail. In summary, cutting earlier, managing nutrient requirements, investing in new leys and attention to detail are key to regularly achieving high-quality forage. As the financials indicate the financial benefit over a 9,000-litre, 120- cow milking herd can mean a £32,000 saving and the potential for a further £13,000 in increased milk performance. Cutting earlier will also boost yield per hectare and reduce the lignin (no nutritional benefit) content. Weather will always impact our decisions, however, even in the wet years good silage-makers always make better forages and this is due to timing, application and detail.