An ancient fodder crop that had been largely forgotten, sainfoin is experiencing a revival thanks to its ability to reduce ruminant emissions. Agroscope demonstrated a methane- and ammonia-reducing effect for dairy cows fed with fresh sainfoin.
Sainfoin is a fodder legume which differs from other legumes such as alfalfa or clover, mainly in terms of its high tannin content. When these tannins are consumed by ruminants and bind to proteins and other fodder ingredients, they can have an effect in the animals’ rumen. This in turn affects nutrient utilisation and excretion, and depending on content may lead to reduced emissions.
Conserved and fresh fodder produce different effects
Conserving sainfoin reduces its effects to varying degrees due to tannin loss and changes in tannin structure. When sainfoin is fed fresh, however, there is often the problem of changes and wide variations in fodder quality. With this in mind, the feeding of freshly cut sainfoin as opposed to a clover/grass mixture was studied in 16 mid-lactation dairy cows at two different points in time.
Sainfoin influences N excretion and hence NH3 emissions
The study confirmed the reductions in the measured nutrient digestibility previously found in feeding studies with conserved sainfoin as well as the proportional shift in N excretions from urine to faeces, which can have a positive effect on potential ammonia emissions. Due to higher N intake with sainfoin, however, total N excretion was higher than with clover/grass.
Fresh sainfoin reduces methane emissions by 13% compared to clover/grass
The feeding of sainfoin reduced daily methane production by around 13% compared to clover/ grass, and to a similar extent with respect to milk yield. In the present experimental setup, however, this may have been due at least in part to lower fibre intake in the sainfoin group compared to the clover/grass group.
- Compared to clover/grass, freshly fed sainfoin had a methane-reducing effect in dairy cows, without affecting milk yield in the period studied. This effect was at least partially due to the reduced fibre intake.
- In terms of intake, the feeding of sainfoin results in a higher proportion of N excretions through faeces rather than urine, which can have a positive effect on potential ammonia emissions. Since N intake was generally higher with sainfoin, however, the amount of urinary N excreted daily did not decrease overall.
- The essential problem of fluctuating fodder quality associated with the feeding of green-fodder means that sustainable emission-reducing effects of sainfoin are difficult to deduce.