Dairy cows fed a high-sugar ration are happier, healthier and better producers, says Dan Skow, a Fairmont, MN, veterinarian. But don't think molasses is the best solution. Hay high in carbohydrates is the way to go, says Skow, who also owns a soil testing lab.
“The higher the sugar content, the less hay it takes to make a pound of milk. You've also got a healthier animal and a greater chance of getting better reproductive performance. Another factor is that the total protein of the milk goes up,” he claims.
To produce that high-carbohydrate hay, however, growers have to know what's in their soils — and what isn't, Skow says. His lab, International Ag Labs, in Fairmont, recommends that growers keep alfalfa ground balanced with the right nutrients to avoid hollow-stemmed hay.
“When you have hollow-stemmed hay, there's a shortage of available calcium, and boron, to the crop during the growing season.”
Hay with a 1:1 calcium-potassium ratio, and a 10:1 nitrogen-sulfur ratio, plus adequate amounts of phosphorus, boron, magnesium, zinc and other trace minerals, produces solid stems. Solid-stemmed alfalfa is healthier for the cow and also provides more sugar, Skow says.
“As the ratio of calcium to potassium goes up to 1:3 or 1:4, we'll start to see milk fever-type symptoms and displaced abomasums. And the uterus will lack tone and affect the ability to reproduce. Cows have also dropped dead with heart-attack-like symptoms.
“As we corrected the calcium-potassium ratio, the cows quit dying,” he says. “We can add calcium to the diet, but I learned it was simpler to get proper hay, something the dairy industry is realizing with its ads for low-potassium hay.”
With solid-stemmed hay, dairy cows have few acidosis problems, too, he adds.
Skow's lab has developed a sugar index to help growers and dairymen know how much sugar their hay contains on a dry matter basis. “The sugar test is an accurate indicator of the real feed value of any grass or alfalfa, and it's based on the use of the refractometer. It's calibrated to measure the percent sucrose, but we're actually measuring the total dissolved solids in the sample plant.”
Dry hay is sent to the lab, ground to a fine powder and blended with water. A digital refractometer takes hay readings and they're compared on the lab's sugar index, below:
Excellent — above 45
Good — 36-45
Poor — 30-35
Very Poor — under 30
“When hay is in the 50s on that scale, an increase of at least 10 lbs milk/cow/day can be made with no other change but in the hay. But the sugars cannot go up in the hay without having adequate, overall nutrients available.
“If you travel the U.S., alfalfa hay will be typically in the area of 6-8 brix. We have people raising hay that's 16-18 brix. If you had hay that was running 12-14 brix, I can give you a written guarantee that you're going to have more milk in the bulk tank,” Skow claims.
He adds that farmers should strive for hay with a high RFV as well as a high sugar value. For more information, visit www.aglabs.com.
How much and what kind of sugar should be in your dairy rations is getting a lot of attention these days, says dairy nutritionist Jim Linn of the University of Minnesota.
“Forages are one contributor to the sugar content of rations; however, most of the sugars in ensiled forages have been consumed by the bacteria during fermentation. Well-made, high-quality hay should have the highest sugar content of all forages.
“If I had two hays equal in all quality measurements except sugar content, I would choose the one with the highest sugar content for feeding,” Linn says.
He bases this on some research conducted out West a few years ago. Animals offered a high- or low-sugar forage free choice ate more of the high-sugar forage. However, he is not aware of any more recent studies that have specifically looked at the effect of sugar content in the forage on milk production.
“But sugar is a hot topic in dairy nutrition today. Researchers are looking at how much and what types of sugar should be in the ration. Right now, the guideline is for rations to contain 4-7% of the dry matter as sugar, but that may change with future research,” he cautions.
Nitrogen is the focus of several forage seminars that will be held during the 2005 World Dairy Expo, Oct. 4-8 at Alliant Energy Center in Madison, WI. The seminars, in the World's Forage Analysis Superbowl display area within the Arena Building, are scheduled as follows:
Oct. 5, 10:30 a.m. — “Are We Feeding Our Cows Too Much Protein?” Glen Broderick, U.S. Dairy Forage Research Center, Madison.
Oct. 5, 1:30 p.m. — “Ammonia Emissions from Dairy Animals,” Mark Powell, U.S. Dairy Forage Research Center.
Oct. 6, 10:30 a.m. — “Getting More from Forage Nitrogen: Rede-signing Alfalfa to Save Protein During Ensiling,” Ronald Hatfield and Richard Muck, U.S. Dairy Forage Research Center.
Oct. 6, 1:30 p.m. — “Herding Cats: Managing Nitrogen Sources for Forage Production,” Michael Russelle, USDA-ARS, St. Paul, MN.
Oct. 7, 10:30 a.m. — “Nitrogen Analysis of Forages: Net Carbo-hydrate and Protein Model,” Larry Chase, Cornell University, Ithaca, NY.
Oct. 7, 1:30 p.m. — “Alternate Forages to Replace Winterkilled Alfalfa,” Paul Peterson, University of Minnesota, St. Paul, MN.
Oct. 8, 10:30 a.m. — “Real Life: Nitrogen Use at the U.S. Dairy Forage Research Center Farm,” Rick Walgenbach, U.S. Dairy Forage Research Center.
Oct. 8, 1:30 p.m. — “Make Milk or Manure: Using Carbohydrates to Reduce Nitrogen Excretion,” Mary Beth Hall, U.S. Dairy Forage Research Center.
For more info, call 608-224-6455 or visit www.world-dairy-expo.com.