This is an appeal to public institutions to discontinue the publishing of alfalfa disease ratings and to be more thoughtful in the use of milk per acre in interpreting research data.

Alfalfa Disease Index

A couple of months ago I sent out information to some university personnel concerning the alfalfa Disease Index.

All new alfalfa varieties now have adequate resistance to the diseases that make up the Disease Index. This should be apparent by the small yield advantage of present varieties over Vernal, now over 50 years old and with a DI of 13. If this is not sufficient evidence, I direct you to the “Physiological genetics of alfalfa improvement:, past failures, future prospects” an excellent analysis of the yield, disease resistance and winter-survival based over 200,000 observations.

The DI has become a marketing tool that has cost the farmer by paying more for his seed and often getting less performance. (Newly released alfalfa varieties always cost more, but too often give less performance) In addition the DI has forced breeding for the DI marketing gimmick, likely resulting in less progress for traits of economic importance. ( I know this as an alfalfa breeder, marketing people still insist on a high DI)

In addition, the disease ratings are not independent ratings, but unverified ratings from the companies marketing the variety. Some of these rating are incorrect. I sent a variety with two HR ratings to an independent lab and they barely made MR. I found other cases where the disease ratings claimed was not the same as when the variety went before the review board. For either reason, that the variety was bred for HR levels, (with probably a lower yield) or that the data may be incorrect for marketing purposes, I would stay away from varieties with near perfect DI, if for no other reason than to send a message.

Milk Per Acre As applied to cutting height

In NZ, where milk is produced entirely on grass, where there are no additional acres available, where cattle need no housing, no machinery is necessary, no feed storage and milking is in highly efficient milking parlor sheds, milk per acre sounds like it would be very meaningful. To take this concept and apply it to confined systems here in the states is leading to some damaging situations and recommendations. If a confinement system can accommodate additional cows and there is no additional land available, then milk per acre might have some value. However, if land is available or a dairy is producing other non-dairy use crops, then yield differences put in the added value milk per acre overwhelms possible important advantages in quality.

Two presently marketed Pioneer varieties, 54V46, a LH susceptible variety, averaged 0.6 ton higher yield per acre per year than 54H91 a LH resistant variety. This is the average for harvest years 2, 3 and 4 in 34, 27 and 19 trials according to the Wisconsin ‘compare varieties‘. I might add that this is the only comparison that can be made with any substantial number of trials, since other companies put their LH resistant varieties only in leafhopper trials. At a RFV of 150, 0.6 tons of hay will produce 1460 pounds of milk per acre, which at $15 per Hwt would be worth $220. According to milk per acre, each leafhopper treatment assuming you had to treat twice a year, would return $110. Silly? Of course. (I don’t mean to infer here that Pioneer is making such a claim, just the opposite, Pioneer is allowing growers to make a comparison, most other companies are not).

Years ago when I was started working for a seed company, where the competition at that time was still the public variety, Vernal, they were introducing a new variety which at that time was 4% higher yielding than Vernal. Four percent doesn’t sound like much, so they advertised X amount more milk per bag. I don’t recall the numbers, but a 4 ton yield times a 4% yield increase times 3 acres seeded times 4 years at today’s $15/Hwt of milk comes out to $400 over Vernal. Silly? Yes, if you think about it, but this is a added value ploy often used in advertising.

Recently there has been studies that have resulted in recommendation to cut alfalfa as low as possible. This recommendation is made on the basis that the lowest cutting height will result in the most milk per acre. It is hard to believe harvesting the bottom 3rd or 4th inch of highly lignified, leafless stem will lead to more milk. I thought there might be a big differences in the second and third cuts, either because of shading with less heat and light getting to the crown buds or due to leaving inoculums and insects in the field. This was not the case as in either the Weirsma or the W H Miner study; the big difference was in the first cut. The Weirsma study claims ½ ton increase in yield or 900 pounds of milk for each inch of lower cut. This would mean almost ½ of the yield came from the stem fraction between 2 and 6 inches. This doesn’t seem possible unless the crops were extremely short. According to the graphs presented, the biggest yield decline came between the 4 and 6 inch cuts.

In the WH Miner study, the 2 inch cut was worth 2615 pounds of milk per ton and 2813 for the 4 inch cut for a difference of 198 pounds. Apparently the quality difference between the 2 and 4 inch cut is greater than the difference between the varieties in a Minnesota study that was 146 and 179 RFV. The high value given alfalfa in terms of milk per acre blows away any difference in RFV, yet we know obtaining alfalfa quality has been a major problem for dairy producers. Also if you are getting high enough quality for maximum milk production at a 2 inch cut, you may be harvesting too early. At the late vegetative stage, yield per day is just reached the highest at 200 to 250 pounds per day. Later harvest means faster recover after cut, better winter-survival and better stands resulting in higher yields in later cuttings and years. In addition, if you are curing hay, the higher stubble height will aid in drying. I would conclude the most milk in the tank and profitability on most farms would come from a higher cut.

When I first started working on alfalfa 40 years ago, the recommendation was to cut at 1st flower or 10% bloom because that harvest schedule produced the most nutrients per acre. Milk per acre wasn’t around at that time, but the most nutrients per acre would mean the most milk per acre, yet dairy quality hay today is cut at the bud stage. Cutting as low as possible or at 10th bloom makes good sense for beef cows and maybe some other livestock classes, but certainly not for today’s high producing dairy cattle.

I would recommend cutting dairy quality hay low enough so as not to leave any leafy material in the field, yet high enough not wreck your machinery, add dirt to your ration and leave stubble to aid in drying. In a droughty year, when hay is very short, each lower 1 inch cut will add 5 or more percent to your yield. For non-dairy quality hay a low cut will be most profitable.

Milk Per Acre As applied to evaluating quality differences between varieties

I am also enclosing (attachment) some old university of MN alfalfa quality data that I worked over. Varieties are ranked in milk per acre and as you can see is virtually identical to the yield per acre ranking. In MN and WI hay auctions, RFV over the years has averaged 95 cents per RFV point per ton. The varieties are based on X amount per ton plus 95 cents per point RFV over the lowest RFV variety. (I did these calculations years ago, I have seen 85 and 90 cent figures, but these number should not radically change things) The $30 per ton might represent the value in the field. The $80 and $100 would represent the value of delivered hay. The highest value variety at the 100/ton base would be P138 worth $122/ton. At $300 per ton, the differences in quality becomes totally meaningless with the ranking of yield per acre the same as the milk per acre ranking. At reasonable base values of $30 to $100 per ton, the rankings are almost reverse the milk per acre ranking. The variety ranking first in milk per acre comes in dead last when valued at $30 per ton plus 95 cent per RFV point per ton. The variety ranking 29th in milk per acre comes in 1st at $30 and holds a good position through $100 per ton.

Click here to see attachment

Here is another way to look at it. I understand 150 RFV and above is dairy quality hay. In one of the MN quality studies, a variety with 126 RFV (not dairy quality) was worth 2283 pounds of milk per ton, in another test, a variety with RFV of 160 (dairy quality) is worth 2432 milk per ton. This is a small 149 difference in milk per ton, but apparently a big difference in the milk bossie is going to put in the tank according to what farmers are willing to pay for quality alfalfa.

There are very few varieties being entered in the MN-WI quality trial, I suspect milk per acre is part of the reason why and also likely is reducing the effort going into breeding for higher quality.

I believe the Disease Index and Milk Per Acre have been useful (profitable) to some companies and apparently some university personal, but has been harmful (not profitable) to many dairymen.

I am appealing to public institutions to drop publishing the disease ratings. I do not think a company would find it in their interest to market a susceptible variety as resistant. University publishing of disease claims only give the illusion to farmers that these are important and more than just company claims. I also ask milk per acre not be used unless

it can be shown to be meaningful to the subject and not biasing data presented.