Ronald L. Boman
USU Extension Dairy Nutritionist

In the July issue of the "Dairy Newsletter" I wrote about the sad state of affairs of the rained on first crop of alfalfa. Now the situation has become even more serious because many dairymen have had all three (or four) crops rained on and the availability of dairy quality hay is limited.

THE ANSWER TO THE PROBLEM OF POOR QUALITY ALFALFA HAY IS NOT TO JUST FEED MORE CONCENTRATES. We need to make certain that the effective fiber requirements of the lactating dairy cow are satisfied. Low fiber intakes that occur with high grain feeding when cows don't consume enough forage (because of poor quality hay) frequently result in rumen acidosis. This acidosis not only throws the cow "off feed," but toxins (associated with acid rumens or low pH) can cause subclinical laminitis (founder or sore, tender feet).

We've seen a number of cases of subclinical to acute laminitis lately in herds where poor quality hay is not consumed in sufficient amounts and concentrate (grain) feeding is increased in an attempt to maintain milk production. Barley in the concentrate increases the likelihood of the problem occurring. Barley is fermented quickly and extensively in the rumen. Barley should be limited to no more than 12 lbs/cow/day. Corn and by-product feeds can make up for the barley that is being eliminated.

If dairy producers must feed the lower quality hay they have on hand, here are some suggestions that will help avoid rumen acidosis and subclinical laminitis and hopefully maintain somewhat acceptable levels of milk production.

1. Get an analysis of your hay from a reliable forage testing laboratory. It is important to know the chemical composition in order to properly balance nutrients in the ration.

2. Have your ration and feeding regime analyzed by a competent professional nutritionist. One that understands ruminant nutrition and physiology and has "cow sense."

3. Be sure to have fresh TMR or loose hay available to the cows each time they exit the milking parlor. This not only will encourage forage consumption, but it allows time for the teat sphincter to close before the cow lies down, thus minimizing bacterial contamination and mastitis.

4. Feed TMR and loose hay in small amounts more frequently. This will encourage more forage consumption.

5. Diamond V Yeast has been shown to increase cellulolytic bacteria in the rumen. These bacteria help to break down cellulose (fiber) producing more acetic acid which shunts the rumen away from lactic acid production (lactic acidosis). Diamond V Yeast also stimulates the cow's appetite. An extra pound of dry matter consumed equals 2 to 3 pounds more milk. Feed 1/4 pound of regular Diamond V or 0.15 pounds of Diamond V "XP" yeast per cow per day.

6. If you are buying hay, insist on a guaranteed analysis. Look at relative feed value (RFV) as well as protein content. Relative feed value is based on the content of Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF). ADF is indicative of digestibility and NDF is indicative of consumption.

Low quality (full bloom) alfalfa will have an RFV of 100 and intake will be severely restricted. Dairy quality alfalfa will have an RFV of 160 to 180 and above. If you happen to have or buy hay with an RFV of 200 or above, it should be combined with lower quality hay to prevent bloat and to slow down rate of passage. The following table (borrowed from Kansas State Dairylines) illustrates the effects of quality (RFV) on dry matter consumption and income over feed cost.

Table 1. Effects of Alfalfa Quality on Dry Matter Intake
Alfalfa RFV
Alfalfa DMI (lb)
Estimated Milk (lb)
Feed Cost
(cwt milk)
Income Over Feed Cost/Cow
Alfalfa Prices: RFV 160 = $120.00, RFV 149 = $115.00, RFV 138 = $110.00,
RFV 129 = $105.00, RFV 107 = $100.00 (Kansas Prices). ©