Home | Search

Easy Field Method for Predicting Hay Quality at First Harvest:
The Montana Haywatch Program

By Marc King, Virginia Knerr, Kenneth Lee, Ron Carlstrom, Lisa Schmidt, Kirk Denny, Chet Hill and Dennis Cash, MSU Extension Service.  From:   1998 Montana Hay Growers Conference Proceedings, Mont. Agr. Exp. Sta. Spec. Rep. 102, pp. 56-62.  This project was partially funded by generous support from the Montana Alfalfa Seed Committee as grants in 1993-1996.

Alfalfa is the major hay crop in North America.  In Montana, the cash value of all hay harvested exceeds $300 million per year.  Most of the hay produced in Montana is fed on-site, however there is growing interest in producing alfalfa hay as a cash crop.  Since 1992, alfalfa acreage in Montana has expanded by 400,000 acres to the present total of 1.7 million acres.

Much of the hay shipped out of state is destined for dairy markets in the Midwest, or shipped to the Pacific Northwest for processing or export (directly or to displace PNW hay).  The dairy hay market is driven by forage quality.  Milk productivity is highly related to high quality alfalfa, and premium prices are routinely paid for forages with high protein/low fiber values (for further details, see MSU Extension Service MontGuide 9302).  Historically, Montana hay prices are lower than other states, and cash premiums for quality hay shipped outside Montana justify the hauling expense.  A few studies have shown a benefit from feeding high quality hay to steers or replacement heifers, but most beef producers are hesitant to buy high quality hay at a higher price.  Because of the importance of alfalfa forage quality to its potential value, we have conducted several studies to assist producers in optimizing hay yield and quality.

Importance of first cutting hay: In both 1995 and 1996, about 3.75 million tons of alfalfa hay were produced in Montana.  For most of the state, 1995 was cooler and wetter than normal, while 1996 was dry and hot, as reflected by production (Table 1).

Table 1.  Montana alfalfa acreage and production, 1995-96 (From 1997 Montana Ag. Statistics).

During the same period, first cutting yields in MAES alfalfa trials accounted for 60%, and second (plus third if taken) cut accounted for 40% of the season total tonnage under irrigation.  In dryland, first cut accounted for 83% of the total season=s hay production.  Based on these numbers, about 70% of all Montana=s alfalfa hay supply is first cutting.

The timing of first cutting alfalfa is very critical for Montana producers trying to optimize hay yield and quality under irrigation.  Due to our short growing season, harvest in a three or four cut system is difficult.  For most of Montana, the final seasonal harvest should occur prior to mid-August to allow for carbohydrate storage in the roots (the final annual harvest should occur after a killing frost, usually in October).  The most important management tool to optimize hay production in our short summers is the timing of first cutting hay.  Frequent rainy weather seems to always occur in June, but the earlier the first harvest is completed, the more potential exists for good second and third cutting hay - possibly more yield is shifted to later cuts, and the later cuts occur during better haying weather.

The Montana Alfalfa HAYWATCH Program was initiated in 1993 in 10 counties to monitor forage quality of standing alfalfa and help producers predict timely cutting dates.  The project was expanded, and through 1997, we sampled alfalfa at 122 sites in 22 counties (Table 2). 

The MSU Extension Agent in each of the counties arranged with producers to sample standing alfalfa for its stage of maturity and forage quality.  For seven consecutive weeks, from mid-May to early July, the agent made maturity measurements, then sent the dried forage to MSU-Bozeman for analysis.  The mean stage by count (MSC) method was used to determine the alfalfa stage of maturity.  Five random 1-foot samples were clipped, and from 50 to 75 stems were each scored by the MSC method and averaged (see Fig. 1).  Samples were collected each Monday, and were shipped to Bozeman for NIRS analyses for crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and relative feed value (RFV).  In 1993 and 1994, all MSC and NIRS forage quality results were available to county offices each Friday.  In 1995 - 1997, MSC values and forage quality values predicted by MSC were available in all county offices.  Over the five years, several newspapers and radio programs published up-to-date forage quality, and the information was also available on the Montana Crop Health Hotline.  Initially, the county agents were responsible for scoring and sampling, but since 1995 several producers have handled their own HAYWATCH samples.

The seven-week sampling period for HAYWATCH monitored alfalfa from a very vegetative state in the third week of May to about July 4 - historical first cutting date in Montana.  The agent flagged a portion of the field at each site to maintain an unharvested area.  At the completion of baling, the agent pulled core samples from each HAYWATCH site, and all of these results were available to producers.

Results: Over the five-year period, producers experienced all extremes of precipitation and climate for making first cutting hay.  In mid-May, alfalfa at most sites was typically less than 6 inches tall, but by early July most were in bloom.  Alfalfa stage of maturity is closely related to accumulated growing degree days (in further MSU research, we have studied that correlation).

In handling the data, the samples were subdivided into three groups: intermountain and western valleys, central Montana, and the Yellowstone and eastern river valleys.  At the conclusion of the study, we combined the central and western Montana data, as the results were very similar.

Table 2.  HAYWATCH program counties and sites, 1993-97.

In eastern Montana, the average MSC of alfalfa in the third week of May was about 1 (vegetative, 6 to 12 inches tall) to 5 (early bloom, Fig. 1) in early July.  Samples from western and central Montana followed the same progression in maturity, but were about 1 MSC unit behind the eastern samples at all dates.  Average crude protein declined from about 27% to 17%, and relative feed value dropped from over 200 to less than 120 in the seven-week period (Fig. 1).

Prediction equations were developed from the MSC and forage quality values for 661 samples taken from 1993 to 1997 (Fig 2).  The linear fit of these were good, since samples came from 22 counties on different varieties and soil types, MSC scores were determined by about 25 different people, and the wide range in weather conditions from 1993 through 1997.

How do I use this information?  Obviously, the easiest way to use this data would be to look at the charts in Figure 1, and predict CP and RFV of your standing hay by calendar date.  This is NOT recommended - depending on year and site, the dates were off by 7 to 14 days. 

The better prediction would be to spend 15 minutes to determine MSC, and run it through the equations listed in Figure 2:

Summary: Several different methods have been used as a quick tool to predict forage quality of standing alfalfa.  For example, in California, a yardstick has been developed to measure the height of the tallest stem, and combined with the maturity score is used to predict ADF and TDN.  In Montana, the HAYWATCH program has provided us with five years of data on 661 samples, and the MSC method is a good field estimate of forage quality for first cut alfalfa.  In the future, we will have the opportunity to design our own yardstick if the method works.

In Montana, first cutting date is extremely important.  We have now fine-tuned the growth stage at which standing alfalfa meets a desired forage quality level.  Unfortunately, during the past five years, we had poor haying conditions in June of three years, and the best-educated producer with HAYWATCH data in hand could not cut Aearly@ or even at a Anormal@ date.  Also, many Montana producers have large tracts of hay to be cut, and it is difficult to manage a large number of acres by a single date.  Additionally, none of these prediction methods take into account forage quality losses during haying.

The single major conclusion which can be made from the HAYWATCH program is that the decline in forage quality is rapid.  A good rule of thumb for most beef producers is to harvest at 10% bloom, to optimize both tonnage and quality.  From the HAYWATCH data, it is obvious that in order to harvest dairy quality hay (>20% CP, <30% ADF, <40% NDF, >150 RFV), cutting has to occur before the plant reaches an MSC of 3 - bud stage, with no flowers. 

The most important management tool to optimize hay production in our short summers is the timing of first cutting hay.

RELATED STORIES

Growing Alfalfa for Hay