Farming Magazine - December, 2012
Forages: Recent Progress in Breeding High-Quality Forages
Until recently, quality improvements in alfalfa were very slow in coming. Yields increased slightly over the years, but at nowhere near the rate farmers experienced in corn and soybeans. Much of this alfalfa yield improvement was "defensive" (better disease resistance) instead of "offensive" traits that would lead to higher yields while maintaining quality. In the past 10 years or so, a number of commercial alfalfa varieties have been promoted as having higher forage quality, and in some cases these claims have been verified by university testing.
The most recent excitement in alfalfa quality is one developed by Cornell University plant breeders, a variety called "N-R-Gee." This variety is the only one selected for a higher concentration of neutral detergent soluble fiber (NDSF). We often think of increased fiber levels in forage as bad, since they can reduce intake, but this type of fiber, which has very high pectin content, is a quality plus.
N-R-Gee doesn't sacrifice yield for forage quality. In Cornell University trials, when compared to WL322HQ, an excellent alfalfa variety that was bred for improved forage quality, N-R-Gee not only outyielded WL322HQ by 6 percent, but was 2 percent higher in NDSF. Also, when compared to the old standby variety Vernal, N-R-Gee was 6 percent lower in NDF (the "bad" fiber in forages) and 5 percent higher in feed efficiency.
What could these quality improvements mean to the bottom line for dairy farmers? N-R-Gee would be expected to result in increased dry matter intake compared to Vernal alfalfa, assuming a dairy ration where alfalfa is 50 percent of the diet. More importantly, the combination of higher intake and improved digestibility would increase daily milk production by over 3 pounds of milk per cow. Production gains like this are what the dairy industry has long been awaiting; for too many years we've seen steady improvements in corn silage quality and yield, while alfalfa has just sort of "been there."
Selecting forage grasses for quality
I was one of the early fans of low-alkaloid reed canarygrass varieties. This native grass had been part of dairy forage programs for generations, but many considered it a low-quality "swamp grass." Alkaloids are bitter nitrogen-containing compounds that can reduce the intake and performance of ruminants. Some alkaloids reduce palatability, while others can cause diarrhea in addition to reducing intake. When Palaton reed canarygrass, the first low-alkaloid variety, was released and soon followed by several other low-alkaloid varieties, I started encouraging farmers to try the "new reed canarygrass." They did, and many really liked it. Canarygrass grows well under very wet conditions, and responds well to both manure and commercial nitrogen fertilizer. One of the reasons it tolerates wet conditions is that, unlike other forage grasses, reed canarygrass can take up nitrogen in the ammonia form. So not only does it live, but it doesn't often get that sickly light green color characteristic of grasses growing in water-saturated soils. For years, reed canarygrass was my top choice for a forage grass, both in a clear stand and in mixtures with alfalfa.
However, times change and we need to change with them. Tall fescue was another forage grass with a shady past - in this case endophytes that lived within the fescue plants and, like alkaloids in reed canarygrass, had the potential to reduce animal performance. However, when endophyte-free tall fescue varieties hit the market, farmers soon started planting them and many (most from what I hear) have been pleased with their performance.
Seed companies soon started aggressively selling tall fescue seed, and the number of varieties on the market seemed to explode. Cornell University started testing tall fescue in comparison with tried-and-true species such as timothy, orchardgrass and reed canarygrass, publishing the results in annual research summaries. What I started to notice is that tall fescue was comparable to canarygrass in yield while maintaining a distinct quality advantage, both at the boot stage (when forage grasses should be harvested) and at heading (alas, when many farmers get around to harvesting forage grasses).
Tall fescue has another advantage over reed canarygrass, in that it is much more aggressive as the season starts to wind down in the fall. With those first chilly nights, canarygrass growth slows down and the foliage soon turns an unhealthy-looking orange color. Tall fescue, on the other hand, continues to grow well into the fall, resulting in what pasture-based farmers call "stockpiled" forage.
About 10 years ago, Miner Institute seeded a pasture to a mix of several species, but primarily tall fescue. The second year after we seeded this pasture, I walked through it in late October and was amazed at the amount of lush forage present - primarily tall fescue. No other forage grass we'd ever grown produced fall growth like tall fescue.
Forage grasses deserve some respect
In major league baseball, many trades between teams include a "player to be named later." Seldom is this player a star or even a starter; usually he's a minor leaguer with modest potential at best, or was a benchwarmer for the team that traded him. Unfortunately, too many farmers take care in selecting an alfalfa variety for their farm, but then give little consideration to the grass to be seeded with the alfalfa; the grass is the "player to be named later."
However, there are considerable differences in forage quality among grass species, and sometimes a big difference in heading date among varieties within a species. For instance, Cornell University forage variety trials have shown that the earliest-maturing orchardgrass variety may reach the boot stage, generally considered the ideal combination of yield and quality, well before the alfalfa is in the bud stage. The result is that the orchardgrass will reduce the quality of the alfalfa-grass forage. Most forage grasses within a particular species have similar quality when harvested at the same stage of maturity. However, there's enough range in maturity, especially within the orchardgrass and timothy species, that care should be used in selecting not only the grass species, but the variety as well. Consult with your seed dealer to select the forage grass that best fits your soils and crop management.
Ev Thomas has worked as an agronomist in New York for 45 years, first with Cornell University Cooperative Extension, then with the William H. Miner Agricultural Research Institute in Chazy, N.Y., including managing its 680-acre crop operation. He continues to work part-time for Miner Institute and is now an agronomist at Oak Point Agronomics. He has written our Forages column for 15 years and has been an expert contributor on a number of other topics.