These highly nutritious plants were an important
forage for heavy working horses in
agriculture, and are still an excellent source of
nectar for honey production as well as
pollen for bee food. Because sainfoins are rich in
tannins which protect
proteins from
hydrolysis in the
rumen, the proteins are instead absorbed in the
abomasum.
Onobrychis typically have a deep
taproot and so are very
drought resistant, but do not recover well from
overgrazing. Adapted to slow but steady growth in the
arid steppe belt of
Eurasia, sainfoins are difficult to establish as pasture, are not persistent in grassland, and only yield one crop of
hay or
seeds per year. Thus they are seldom grown in any significant extent, though
O. viciifolia is met with somewhat more regularly.
Nutrition Sainfoin provides a superb forage for grazing animals and voluntary intake of sainfoin by
cattle and
sheep is 20% higher than for
grass. Unlike many other legumes, it is non-bloating and is known to have anthelmintic properties, so reducing the problems associated with livestock
worms. Sainfoin contains
condensed tannins, and it is these that protect animals against bloat. Sainfoin has also been shown to increase
protein absorption. This, combined with its other health benefits, mean that animals grazing sainfoin have very rapid liveweight gains, so young stock can be finished sooner and with very good carcass grades. Sainfoin is therefore extremely useful to low input and organic farmers. Yields can be very high at around 16t DM per hectare. Methods and research techniques have been studied and developed to look specifically at Sainfoin polyphenols which include
tannins and flavonoids. There are significant differences between Sainfoin types and this will lead to further development of Sainfoin plant breeding. One method for improving
nitrogen utilisation by ruminants and reduce greenhouse gases (CH, NO), without altering their
nitrogen and energy value, is to use forages that contain
condensed tannins, such as sainfoin. The
nutritive value of sainfoin, despite its lower
nitrogen content than lucerne, is high. Future research, on the nutritional impact of
condensed tannins is likely not only be based on
condensed tannin content, but also include structure-activity considerations. The results obtained, with sheep at maintenance fed a diet containing only sainfoin will be tested with producing animals, for example growing
sheep and
cattle, lactating ewes,
goats or
cows. In producing animals the diet will comprise different forage sources and supplement feeds. Sainfoin is seldom used as a pure crop and is generally introduced in pasture in a
grass-legume mix with cocksfoot (
Dactylis), ryegrass (
Lolium) or with other legumes such as red clover, white clover or lucerne. Results have shown the choice of the variety is important. A variety like Esparcette, characterised by the highest
condensed tannin content, may provide beneficial effects with a lower proportion in a mixture with other legumes. Preserving legumes, as
silage, is a good way to provide an on-farm source of home-grown energy and
protein, offers advantages over traditional haymaking, being less weather-dependent, and allows a high quality of forage during the harvesting period. In particular, wrapped
silage bales of sainfoin have great potential in animal nutrition and can be used by farmers, as found that
condensed tannin effects were not reduced by this mode of preservation. ==In culture==