Improved Dairy Alfalfa-Grass Mixtures

Improved Dairy Alfalfa-Grass Mixtures

by Joel Bagg, Forage Development Specialist & District Sales Manager, Quality Seeds Ltd

Suitable grass species and varieties can offer significant advantages when included in alfalfa-grass mixtures for dairy cows as haylage, baleage or dry hay. These advantages include nutritional improvements in fibre digestibility, increased intake and higher milk production, as well as agronomic and harvest advantages. There is currently a great deal of interest by dairy producers to include newer grasses in alfalfa-grass mixtures, and a move away from the use of timothy. Improved Quality Seeds varieties of orchardgrass (Dividend VL), tall fescue (Cowgirl), meadow fescue (Pardus), festulolium (Lofa), and perennial ryegrass (Tetragain) offer significant benefits.

 

1.  Agronomic Advantages

Alfalfa-grass mixtures typically yield higher than straight alfalfa stands. Yield improvements of more than 20% have been reported. Nitrogen fixed by the alfalfa is used by the grasses to meet their high nitrogen requirements. Grasses have much less issues with persistence and are more tolerant to variable drainage, low potassium fertility, disease and winterkill. Grasses in mixed stands provide some protection against lodging and also are better able to compete with weeds.

 

2.   Harvest & Storage Advantages

Grasses in mixed alfalfa stands enable faster wilting and drying, resulting in reduced respiration losses of non-fibre carbohydrates. Because alfalfa tends to buffer itself during haylage fermentation with a slower drop in pH, grasses can also improve fermentation, particularly in baleage situations.

 

3.    Dairy Cow Nutrition Advantages

Grasses tend to lose forage quality faster than alfalfa after the heading stage, so it is critical that cutting schedules be timely. Unlike in the past when first-cut was started in mid-June and it was followed by one or two cuts, most dairy producers today begin in late-May and aim to cut every 4 weeks. Grass mixtures can work very well with current cutting schedules. Early-cut grasses are very palatable and can complement alfalfa nutritionally.

Grasses are higher in fibre (NDF) than alfalfa, but are also much higher in fibre digestibility (NDFD). Refer to Table 1 – Fibre (NDF) & Fibre Digestibility (NDFD) Levels of Alfalfa & Grass. Although there is a wide range, grasses may have 12 – 13 % points higher NDF than alfalfa, but grasses also have 12 – 13% points higher NDFD.

Higher fibre digestibility has two benefits – higher digestible energy and higher cow intake, resulting in more milk per cow. This is especially the case where intake is limiting production – transition, fresh and high producing cows. A much quoted study by Oba & Allen, MI State 1999 concluded that for every 1 percentage point increase in NDFD, intake increases 0.37 lbs/day and milk increases 0.55 lbs milk/day. Dr Jerry Cherney, Cornell University, has stated “Feeding trials across the USA have shown that a one percentage unit increase in NDFD increases milk production by 0.5 to 1.0 lbs/cow/day, and more than 1.0 lb/cow/day for the highest producing cows”. Grasses in early cut alfalfa-grass mixtures can complement the alfalfa by improving fibre digestibility. Even small percentages of grass in an alfalfa-grass mix can provide significant improvements in NDFD.

Table 1 – Fibre (NDF) & Fibre Digestibility (NDFD) Levels of Alfalfa & Grass

(Source – Dairy Forage Lab, Ithica, NY and Miner Institute)

Nutrient

Alfalfa

Mean

Alfalfa

Range

Grass

Mean

Grass

Range

NDF%

43.7 38.2 – 49.3 56.7 49.9 – 63.4

Lignin %

7.4 6.1 – 8.6 5.2 3.5 – 6.8

NDFD %

(30 hr)

51.5 45.4 – 57.6 63.3 56.4 – 70.1

When nitrogen is not limiting, grasses have moderately high crude protein levels, but not nearly as high as alfalfa. Alfalfa often has very high crude protein (CP) levels, but the CP is very soluble, limiting its efficient utilization by the cow. Mixed alfalfa-grass stands can have high CP content with better utilization.

 

Rumen Dynamics

Alfalfa and grasses can complement each other in a dairy ration. As discussed previously, grasses have higher fibre (NDF) levels (~12% points) than alfalfa, but they also have greater fibre digestibility (NDFD) (~12% points, 30 hours). Grasses also have lower levels of undigestible fibre (uNDFD240). While alfalfa fibre has an initial faster rate of digestion, it then slows down. Grasses have a greater extent of digestion. This results in higher animal intake.

The fibre particles in grasses are less fragile in the rumen than in alfalfa with more longer particles, so the particle size decreases less rapidly. This improves the physically effective fibre (peNDF) in the rumen. This decreases the need to add straw to a TMR to provide minimum physically effective fibre for proper rumen function and cow health, while contributing much more digestible energy than straw.

 

How Much Grass Is Optimum?

Variability of % grass in alfalfa mixtures is a potential issue because it can result in variable quality forage. Keep in mind that % grass in a seed mixture is not the same as % grass in the subsequent forage stand. Some grass species are more aggressive than others, and small seed amounts (as low as 3%) can result in significantly more growth. Percent grass also changes over time and is strongly influenced by environmental conditions such as rainfall during and after establishment.

Early Cornell University research suggests that the optimum grass in alfalfa-grass mixtures at the end of the seeding year may be around 5 – 15% grass, with about 20 – 30% in the first full production year. Cornell University and Dairy One Forage Laboratory have developed NIRS calibration equations to estimate grass percentages in alfalfa-grass samples. (Alfalfa- Grass Mixture – 2016 Update http://blogs.cornell.edu/whatscroppingup/2016/12/02/alfalfa-grass-mixtures-2016-update/)

 

Timothy

Historically, timothy has been the main grass species used in alfalfa-grass mixtures. However, there has been a move away from timothy as many dairy producers have looked for species that are more productive agronomically as well as providing higher feed quality in the ration. “Old school” advantages of timothy include:

  • late heading dates are more suitable to late first-cutting (June),
  • it is less competitive with alfalfa,
  • the seed is small and mixes well with alfalfa to go through the drill small seed box, and
  • the seed is relatively inexpensive.

The weakness of timothy is that it is shallow-rooted with very poor drought tolerance. It is also daylight sensitive which makes it want to grow in the spring but not after late-June with decreasing day lengths. This results in lots of timothy growth in the first-cut, but very little regrowth, making it a “first-cut wonder” with poor seasonal growth distribution. Alfalfa-timothy mixtures are inconsistent across cuttings, having a high percentage of timothy in the first-cut while subsequent cuts are almost straight alfalfa. Other improved grass species tend to have higher seasonal yield.

 

Improved Grass Species & Varieties

 

1.   “Dividend VL” Orchardgrass

Dividend VL is an exclusive Quality Seeds orchardgrass variety that works exceptionally well in alfalfa-grass mixtures. Older orchardgrass varieties have a reputation of early maturity (early May) and poor forage quality, but this has dramatically changed with the introduction of this newer variety. Dividend VL was bred at the University of Guelph to be very late maturing. In Ontario Forage Crops Committee trials at Elora, Dividend VL orchardgrass had much later heading dates than other orchardgrass varieties (more than 3 weeks later than early varieties) and a similar heading date to late-maturing timothy varieties. Research also shows that Dividend VL is slower than other orchardgrass varieties to decline in digestibility and palatability after heading, providing a much a wider harvest window.

Dividend VL has become a staple in many of Quality Seeds alfalfa-grass mixtures with excellent forage quality and high fibre digestibility. Dividend VL is leafy, fine textured and very palatable. It also provides high yields of vegetative regrowth in subsequent cuts. It wilts and dries quickly so it is suitable for haylage, baleage or dry hay. Dividend VL seed is coated so that when mixed with alfalfa and other grass seed at 3 to 5%, it will flow through a drill small seed box. (www.qualityseeds.ca/foragess/native-grasses/dividend-vl-orchardgrass)

2.   “Cowgirl” Tall Fescue

Cowgirl tall fescue is a new “soft leaf” variety that was bred for improved forage quality. It is much softer in texture compared to other tall fescue varieties, and provides a big improvement in palatability. Because of its low lignin content it is very high in fibre digestibility. Cowgirl tall fescue has excellent agronomics and is high yielding compared to other forage grass species. Tall fescue is deep rooted and very drought tolerant, and can provide significant vegetative growth during hot, dry summer weather.

Similar to orchardgrass, Cowgirl tall fescue wilts and dries quickly so it is suitable for haylage, baleage or dry hay. Of course, Cowgirl is an endophyte-free variety. Experience has shown that modest amounts of Cowgirl seed can be included in alfalfa mixtures and still flow through a drill small seed box and provide significant growth. (www.qualityseeds.ca/foragess/native-grasses/cow-girl)

3.   “Pardus” Meadow Fescue

Meadow fescue has recently been rediscovered as an excellent grass to include in dairy haylage alfalfa-grass mixtures. Recent research by Cornell University and Miner Institute shows much opportunity with alfalfa-meadow fescue mixtures. Meadow fescue has higher fibre digestibility than most other grass species. Meadow fescue is less competitive with alfalfa, which can be an advantage in alfalfa-grass mixtures where a modest grass content is more desirable. It has a soft texture and is high in palatability. It yields very well in late summer and has good seasonal distribution of growth.

Pardus meadow fescue is a relatively new leafy variety exclusive to Quality Seeds. Pardus is noted for its very soft leaves and extremely high fibre digestibility. It has strong disease resistance and is very persistent. Similar to tall fescue, small amounts of Pardus seed can be included in alfalfa mixtures and still flow through a drill small seed box. (www.qualityseeds.ca/foragess/native-grasses/pardus)

4.   “Lofa” Festulolium

Festuloliums are crosses between ryegrass and either meadow or tall fescue. They have been selected to have the forage quality and fast growth of the ryegrass combined with the persistence of the fescue.

Quality Seeds Lofa festulolium has inherited high forage quality from its ryegrass parent, but with improved yield, growth during hot dry summer weather, and persistence. It is noted for being very high in sugar content and digestible energy. A strong root system allows it to be more productive in dry summer weather than ryegrass. It is best suited to aggressive cutting schedules in dairy haylage systems. Although it will head out every 28 days or earlier, feed analysis data shows that it maintains its nutrient quality advantage after heading very well. It can be competitive with alfalfa in mixtures so percentage inclusion should be modest. Festuloliums can sometimes be difficult to dry for hay, so they work better when harvested as haylage or baleage. (www.qualityseeds.ca/foragess/native-grasses/lofa-festulolium-pabulare)

 

5.   “TetraGain” Perennial Ryegrass

TetraGain is a new tetraploid perennial ryegrass that is extremely productive in cool and damp climates. It is high yielding under these conditions with good cold tolerance and disease resistance. TetraGain has exceptionally high nutritional feed value, with very high sugar content, fibre digestibility, digestible energy and palatability. Perennial ryegrass can be more difficult to dry, so haylage or baleage is a more suitable harvest option than dry hay. (www.qualityseeds.ca/foragess/native-grasses/tetragain)

Grass Mixtures With Low Lignin “Boost HG” Alfalfa

The newest alfalfa variety at Quality Seeds is “Boost HG”, a non-transgenic, non-Roundup Ready, low lignin alfalfa that was developed by conventional plant breeding using Hi-Gest® Low Lignin Technology. It has much improved fibre digestibility and forage quality through a significant reduction in whole plant lignin. This trait increases digestible energy and animal intake for higher milk production. It provides greater harvest flexibility for higher quality forage. To complement its higher fibre digestibility Boost HG is being marketed in mixtures with high performance, high fibre digestibility grass varieties – Dividend VL orchardgrass, Cowgirl tall fescue, Pardus meadow fescue, and Lofa festulolium.

(www.qualityseeds.ca/foragess/alfalfa/boost-hg-alfalfa)

Pure Grass Stands

These grass species and varieties can also have excellent performance when grown in pure grass stand mixtures when managed appropriately. Quality Seeds also offers the grass mixture “Milk Max”, suitable for dairy haylage and baleage consisting of 25% Dividend VL orchardgrass, 25% Cowgirl tall fescue, 25% Lofa festulolium and 25% TetraGain perennial ryegrass. Fertilizing each grass cut with nitrogen is important for yield and quality. Regrowth is faster and more vigorous when cutting height is 4 inches.

Quality Seeds Grass Variety Research

Quality Seeds has positioned itself to be the Canadian leader in improved grass species and varieties. Searching around the world for new potential “game changer” grass and alfalfa varieties, they are tested in Canadian environments to research how they perform for yield, quality and persistence in our soils and climates. Quality Seeds has been a leader in innovation by introducing new specialty trait grasses, such as late-maturing Dividend orchardgrass, soft-leaf Cowgirl tall fescue, highly digestible Pardus meadow fescue, and high yielding and sugar content Lofa festulolium, as well as the extremely highly digestible Evolution Italian ryegrass.

Figure 1 - Screening for forage nutrient quality and agronomics at the grass variety plots, Quality Seeds, Vaughan, Ontario.