Rumen buffering seen as a must for high protein grass silages

High protein levels in some first cut silages offer many farmers the potential to save on bought in feed costs this winter, however rumen buffering will be a must to ensure milk butterfats are not compromised.
Analysis of 200 first cut grass silage results by Mole Valley Farmers (see table below) shows that protein levels are up from an average 13.7% last year to 14.8% this year. These silages are generally slightly drier, but similar in energy.
However, high protein is not a given, with the range in levels varying from as low as 7.9%, up to as high as 21.3%. As a result, Mole Valley Farmers senior nutritionist, Dr Robin Hawkey urges farmers to analyse stocks on a regular basis.
“With the volatility in soya and bought in protein costs, it’s definitely worth double checking silage protein levels. If they’re as high as many first cut samples, there is money to be saved. Knowing where you stand is also important so rations are balanced correctly,” he says.
Using current feed values for a simple 35 litre ration, an average 2017 silage would save farmers about 6p/cow/day compared to the average in 2016. 
However, if silage protein levels are as high as 18% – which is the case in many silages this year – the saving is more like 25p/cow/day.
Analysing silages at least monthly is also important considering the fact quality losses can occur as fermentation progresses. Protein levels can also vary considerably when moving from one field to the next through the clamp. As contractor’s machinery gets bigger, as do silage loads, the fluctuations can be even more marked.
The lower average NDF (47.6%) and higher lactic acid (56.2g/kg) in this year’s first cuts will promote good fermentation which means silage should feed and milk well. However, Dr Hawkey says this could mean it is not a good winter for butterfats.
With more processors “ramping up” the emphasis on milk constituents, looking after rumen health will be a must. As such, some farmers could consider feeding live yeasts which curb the production of acid in the rumen. Rumen buffers may also be relevant, along with the provision of salt licks.
Low NDF levels also emphasise the importance of managing Rumen Unsaturated Fatty Acid Load (RUFAL) – a new rationing parameter developed by the company as part of its precision nutrition rationing software. This takes into account all of the sources of unsaturated fatty acids in the diet. Increasing RUFAL above recommended values will have a direct negative effect on milk fat content.
Dr Hawkey adds: “We generally think that you need fibre for butterfats, but when there’s the wrong level of unsaturated fats in the ration, biohydrogenation depresses butterfats. By lowering unsaturated fats or RUFAL, butterfats can be increased as well.”