As outlined in my previous article about managing nitrogen use in multi cut silages (June 2018), sugar is a crucial component in forage ensilement and boosting energy supply in all forages. Sugars are referred to as water soluble carbohydrates (WSC) in a grass plant. Lactic acid is produced from WSC which stabilise the forage and prevent devaluation of silage quality from spoilage organisms.
The act of wilting enables us to boost WSC by several times with 24 hours of wilt. Wilting also increases dry matter, reduces protein, decreases silage ammonia and affects lactate and acetate concentrations. High sugar rye grasses contain four times as much sugar as a Lucerne silage and the act on ensilement creates several times as much lactic acid production as opposed to the Lucerne sugars. However, with wet grass silages, clover and Lucerne we do not have this sugar level, although we can improve the situation by wilting crops for longer (up to 36 hours), adding additional sugar and applying inoculants. We should set out to enhance grass sugars, but late silage cuts and Lucerne do need help because weather circumstances and crop limitations affect the obtainable sugar level.
A typical Lucerne silage contains 10 grams of sugar/kilogram which is 20 grams of WSC short of the 30 gram WSC target. To supplement this additional WSC we can add 20kg/tonne of cane molasses sugar which at current market prices would be £2.30 per tonne of silage ensiled.
As nutritionists we often add molasses to a TMR or ration to improve intakes of a poor performing forage, however my question is why do we wait to apply molasses and not apply it earlier at silage making? Surely we know beforehand in some situations; whether growing Lucerne/Clover or a prolonged wet spell before ensilement of a late grass silage.
Secondly, we are better off improving the fermentation of the ensiled forage rather than make the cows eat a poor forage with poor palatability characteristics. This will also have the added benefit of stabilising the forage at feed out and reducing further wastage. We would need to source some molasses before silage making but, in most circumstances, this can be planned for. Lucerne managed well is an excellent fibre source which helps rumen fermentation and milk constituents.
For forage planning, please contact Wesley at firstname.lastname@example.org or your local FCG office.