Sainfoin is an old forage that is receiving renewed interest. It is known as a legume that has low bloat potential and also suppresses internal parasites in ruminants. Sainfoin has these characteristics because it is one of a few legumes with sufficient tannins to bind to and precipitate proteins. Condensed tannins reduce rumen microbial action, gas and methane production, and ammonia content.
Tannins are a class of compounds that bind to and precipitate proteins. They are astringent (causing a dry, puckering feeling in the mouth, for example, in unripe fruits to discourage eating until the fruit has ripened). Some of the most common human dietary sources of tannins include tea, coffee, wine and chocolate. Tannins and phenolic relatives are a large category of compounds, with one study finding over 276 such compounds comprising up to 5% of the dry matter in fresh sainfoin.
Both the type and amount of tannins determine palatability. Sainfoin is extremely palatable, with cattle often selecting it over alfalfa when grazing. Sainfoin has high nutritional quality, being lower in acid detergent fiber (ADF) and neutral detergent fiber (NDF) levels than alfalfa, along with increased digestibility.
Sainfoin is resistant to alfalfa weevil, with some varieties being resistant to other insect and disease pests.
It has more drought tolerance than alfalfa (perhaps being best adapted to areas with limited rainfall, but above 13 inches annually). Sainfoin roots are deep, branched taproots with a stout main taproot. It is especially adapted to areas where dryland hay production is limited to one cutting, or when there is a shortage of irrigation water, it may prove a good substitute for alfalfa.
New varieties are extremely winterhardy and frost-tolerant. While older varieties were lower-yielding, newer varieties may yield similar to alfalfa in moderate to limited moisture ranges.
As a legume, sainfoin fixes nitrogen but has a lower phosphorus requirement than many other legumes. Sainfoin is excellent for honey production, since its flowers are less injurious to honeybees than alfalfa. Sainfoin is also a non-invasive species.
Sainfoin is adapted to much of the northern Rocky Mountains, Great Plains and Great Basin, up to elevations of 6,000 feet. It yields best on deep, well-drained soils with a pH of 7 to 8. It is a good forage legume for sites with calcareous soils, late spring frosts, and plentiful spring and early summer precipitation. Sainfoin does not persist in the wetter soils of the eastern U.S.
Three newer varieties should be considered if planting sainfoin:
- Shoshone sainfoin was developed in Wyoming with resistance to both Northern root-knot nematode and alfalfa stem nematode. It has higher yield than older varieties.
- Delaney sainfoin was bred for higher yield in Wyoming and is best suited as a replacement for Remont. It is considered a multiple-cut cultivar.
- AAC Mountainview sainfoin from Ag Canada (Lethbridge, Alberta) is persistent for both multicut hay or grazing. It has rapid regrowth to keep up with alfalfa and thus mixes well with it.
Spring planting is generally preferred with sainfoin, but the forage can be fall planted in some situations.
When establishing sainfoin, seedbeds need to be well packed and uniformly level before and after seeding. Inoculate sainfoin with rhizobium specific for sainfoin before seeding. Though sainfoin seed is larger than most forage legumes (21,000 seeds per pound with hull or 32,000 seeds per pound if dehulled), it needs to be seeded shallow (½- to ¾-inches deep). Avoid fields with heavy residue cover.
Assuming that pure live seed (PLS) count is at least 95%, a pure stand of sainfoin should be seeded at 25 to 34 pounds per acre when row spacing is 7 inches. If another legume is included, the seeding rate should be halved. For dryland conditions, seed 15 to 20 pounds PLS per acre or 2 to 5 pounds per acre when used as a component of a rangeland mix.
Sainfoin is a relatively poor competitor with weeds the first year because of slow growth and establishment. Management practices the year of establishment should aim to increase crop establishment and vigor. Once sainfoin emerges, only grasses can be controlled with the herbicides (clethodim or sethoxydim). If weed density is high in the establishment year, harvesting to remove weed biomass may be necessary.
Sainfoin usage
Sainfoin grows to a height of 3 feet or more. The stems appear coarse but are hollow, soft and very palatable. Since sainfoin grows upright, it is easy to harvest for hay or baleage. It has excellent leaf retention – better than alfalfa. Harvest at 50% flowering to maximize yields (about one week ahead of alfalfa). Condensed tannin levels are highest when sainfoin is at 50% bloom. First-cut hay yields are often greater than those for alfalfa, but later cuttings commonly yield less than alfalfa. Be sure to avoid harvesting sainfoin four to six weeks before a killing frost in order to allow the plants enough time to build up their carbohydrate reserves to survive winter.
An Argentine study showed that sainfoin hay had lower in vitro organic matter digestibility than silage and fresh forage (thus baleage might be considered by beef cattle growers). However, polyphenol content and condensed tannin content were reduced to a greater extent in silage than in the hay when compared to fresh forages.
Sainfoin is best suited to a rotational grazing system that manages to leave residual leaf and stem material behind (such as in a take-half-leave-half grazing system). Frequent and severe grazing will quickly thin a sainfoin stand, especially when grazed in its vegetative stage. Sainfoin needs to have an opportunity to reseed itself at least once every few years to be able to persist in a forage stand. Also, a fall rest period, as for hay making, is required for stand longevity.
In a recent Utah study, average daily gains of heifers grazing tanniferous legumes (sainfoin or birdsfoot trefoil) were 40% greater (2.3 pounds per day) than of heifers grazing alfalfa (1.6 pounds per day) during the first year. Heifers grazing a three-way choice (sainfoin, birdsfoot trefoil and alfalfa planted together) had greater intakes (22.9 versus 17.2 pounds per day) and average daily gain (2.7 versus 2.1 pounds per day) than those grazing monocultures of any of the three legumes. Research also demonstrated that sainfoin modified rumen fermentation patterns, including a decrease in methane and ammonia production. Inhibitory effects were linked to condensed tannins.
Stands will persist three to six years under irrigation but will last longer if root and crown rot diseases are controlled. Sainfoin does not like being wet for long periods. Yellowing and stand loss will occur in areas that hold soil water or around leaky irrigation gates. Stands should be allowed to naturally reseed every two to three years for reestablishment.
In summary, sainfoin has potential benefits to growers due to its tannin content. Sainfoin survives on 12 to 18 inches of annual precipitation, though irrigation or increased rainfall will increase yield. It does best on deep, well-drained soils and does not withstand wet soils or high water tables. Sainfoin is alkali-tolerant and does best in soils with a pH of 7 and above.
References omitted but are available upon request by sending an email to the editor.
