New Sainfoin Varieties

Background

The desire to improve forage stands without the fear of bloat has piqued interest in utilizing the bloat-free legume, sainfoin in western Canadian grazing systems. It has lower protein levels than alfalfa but contains condensed tannins that appear to reduce protein breakdown in the rumen and improve protein digestion and absorption in the intestine. Consequently, gains on sainfoin pasture can be as efficient and rapid as on alfalfa pasture. Sainfoin is resistant to the alfalfa weevil and grows earlier in the spring and has good leaf retention in the fall than alfalfa. Researchers at AAFC Lethbridge have been selecting sainfoin for improved yield, regrowth and survival in alfalfa stands, and have found that sainfoin’s survival depends partly on the alfalfa variety it is grown with, as well as where it is grown. This current project looked into how to determine which sainfoin varieties are best suited for western Canadian environments and what improvements need to be made to be an efficient legume in binary mixture with grass species destined for grazing or stored feed.  

Objectives

• gain insight into grass/sainfoin interactions in different regions 
• develop new sainfoin germplasm for grass/sainfoin mixed stands  
• determine the nutritional value of new sainfoin and grass/sainfoin stands  
• develop integrated crop management practices to optimize growth and longevity of grass/sainfoin pastures 
• train a forage breeder to maintain forage research capacity in AAFC’s Lethbridge Research and Development Centre 

What They Did

Five sainfoin populations were seeded in small plots (within, between, or across rows) with orchard, meadow bromegrass and hybrid bromegrass in Lethbridge (irrigated), Saskatoon, and Carman. 

Forage quality, yield and sainfoin contribution were monitored for three to five years after establishment. Laboratory tests and in-vitro gas/digestibility trials were conducted using samples from the plots that were collected at times relevant to grazing and silaging.    

The team had planned to identify the sainfoin plants that best perform when grown in grass stands and identify the traits that allow them to do so. However, there were no compatibility issues of any sainfoin populations with any of the three grass species, so the characterization was not needed.  

What They Learned

Sainfoin varieties were compatible with the grass species and were successfully established with how they were seeded having no impact on the sainfoin content in the stand. Some sainfoin varieties performed better than others, with landscape, region and variety being the driving factor. The only issue observed by the team was the inevitable competition of resources between the sainfoin and grasses.  

Orchardgrass with Mountainview and Melrose sainfoin yielded the highest % of sainfoin in the stand in dryland environments with and without irrigation, respectively. The overall best sainfoin-grass mixture based on forage biomass was Melrose with meadow bromegrass in both irrigated and non-irrigated environments.  

If broader adaptation to western Canadian conditions is what you are looking for then, LRC-4498 sainfoin with meadow bromegrass would be the top choice, considering both forage biomass and sainfoin percentage.  

Unsurprisingly, the higher the proportion of sainfoin in the grass mix, the better the nutritive value of the forage regardless of the grass or sainfoin population. Sainfoin also had a higher nutritive value than the grasses by having higher crude protein, and lower ADF and NDF. In an in-vitro setting, increasing sainfoin proportion into cool-season grasses negatively affected the NDF digestibility but did not affect the dry matter digestibility, total gas production and methane emissions. Interestingly, the condensed tannins present in sainfoin counteract ammonia emissions from the rumen, particularly when animals are fed a high-protein diet. This characteristic makes sainfoin an alternative to alfalfa, which lacks condensed tannins, and may contribute to the reduction of enteric greenhouse gases.  

What it Means

This project was able to garner insight on which combination of sainfoin and grass is best suited for the western Canadian landscape. Not only was it validated that sainfoin is a highly nutritious legume that improves the digestibility and nutritive value of the forage stand, but it also establishes easily and is compatible with the cool season grasses it was matched with. The team also noted that during drought sainfoin persisted which overall could improve the drought-tolerance of the existing grass stand.