MFA TECHNICAL BRIEF

Alfalfa hay will deteriorate  

Story by Dr. Jim White

Barns and bale covers are good storage options, sprayed-on fat isn’t

Dry matter loss, quality deterioration and decline in economic value are inevitable in baled alfalfa hay. Substantial field observations and research work have shown that baled hay simply will deteriorate during storage. The magnitude of early storage loss is due principally to damage from precipitation and the subsequent loss of hay solubles. University researchers analyzed the leachate of simulated rainfall on drying hay and demonstrated that hay leaching losses will be greater with increased rainfall and decreased plant moisture content. That’s research revealing common sense.

Of course, one of the most effective management practices for hay is the well turned out barn. Providing an appropriate storage facility will increase equipment and labor costs, however. And when everything gets a place on the balance sheet, the facility costs can exceed the value of the forage quality saved under short-term storage conditions.

Protecting hay with tarps or wraps will increase handling costs, and, at some point, requires disposal of the coverings. Solutions of casein or soybean meal have been applied to baled hay in an attempt to protect forage quality of baled hay stored outside. Oklahoma researchers reported that such sprayer-applied coverings were as effective as tarping hay for storage of 5 months with an inch and a half of rain.

Once upon a time, in the tilting-at-windmills world of protecting hay in the outdoors, there was a hard-working, ruminant nutritionist who tried to protect hay quality by spraying it with a layer of fat. It didn’t work, but here is the story:

Initial baled hay chemical composition was: moisture at 16 percent; crude protein at 15.78 percent (18.75 percent DM); carotene at 15.7 milligrams/kg (18.7 mg/kg of DM). Half of the bales were sprayed with fat, the other half were not, so we’ll refer to the treatments as Fat or No Fat. Half of each set of Fat and No-Fat treated bales were stored in a barn, the other half were stored outside. In researcher speak, it was a completely randomized two-way analysis of variance with barn storage and fat application as factors. The year was unusually wet—from June to June, precipitation was 45 inches.

Visual appraisal: Fat-treated bales stored outside appeared to have more deterioration than the No-Fat, No-Barn bales. A layer of rotted material, black in color, developed on the outside of the Fat-treated, No-Barn bales. This is attributed to inner-bale moisture migration to the fat layer. The No-Barn bales had substantial rot and mold in each bale. They appeared darker, more weathered and more deteriorated than Barn bales. The Fat and No-Fat bales stored in a barn appeared similar. The Barn bales had no visible signs of mold or deterioration.

Nutrient recovery: The table below shows the percent nutrient recovery by storage method and fat application. Comparing fat treatment, the bales had similar recoveries of dry matter, protein and carotene. Comparing barn treatment, the bales stored inside had statistically greater recoveries of dry matter, protein and carotene than bales stored outside. The Fat-by-Barn interaction was not significant. The fat application was not effective in conserving the dry matter, crude protein or carotene in the bales.

Jim White is ruminant nutritionist for MFA Incorporated.

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