Minimizing Losses in Hay Storage and Feeding - MSUcares

MINIMIZING LOSSES IN HAYSTORAGE AND FEEDINGEach year more than 60 million acresof forage crops are harvested for hay inthe United States. Annual productionfrom this acreage is over 150 milliontons of hay valued at more than 12billion dollars. Hay is the most widelygrown mechanically-harvested agronomiccrop in the United States.As a source of nutrition for livestock,hay offers numerous advantages.It can be made from many differentcrops; when protected from theweather it can be stored indefinitelywith little nutrient loss; package sizesand shapes can vary greatly; andharvesting, storage, and feeding canvary from being done by hand to beingcompletely mechanized. Hay often canmeet, or almost meet, the nutrientneeds of many classes of livestock.Because of its many merits, hay isthe most commonly used stored feedon livestock farms across the nation.Unfortunately, losses of hay duringstorage and feeding are often high,particularly with round bales storedoutside in high rainfall areas such asthe eastern United States. It is estimatedthat the total value of haystorage and feeding losses nationwideexceeds three billion dollars annually!On some farms, such losses account forover 10% of the cost of livestockproduction.These are real, and not just potential,losses (time, labor, and monetaryinputs are lost along with the hay).Unfortunately, many producersprobably do not realize how large theirlosses really are, or that with relativelylittle effort or expense they could bereduced considerably. The purpose ofthis publication is to provide informationas to how and why hay lossesoccur, and how they can be reduced.TYPES OF STORAGE LOSSESHay storage losses vary greatly dependingupon several factors, but storagetechnique is of utmost importance.Losses of dry hay stored inside a barnare usually of little concern. However,even for barn stored hay, losses risesharply as moisture levels increaseabove 20%, and losses from roundbales stored outside under adverseconditions can be much larger.During storage, hay can be subject todry matter losses as well as losses offorage quality.Dry Matter LossesDry matter losses during storage resultfrom plant respiration (the continuationof normal plant processes),microbial activity, and weather deterioration.Even at low moisture levels(20% or less) there is some loss due torespiration and low numbers ofmicroorganisms, but this is constantacross hay types and essentiallyunavoidable.At higher moisture levels (above20%) where mold growth is likely tobe visibly detectable, dry matter lossesare greater, and significant levels ofheating (which can also lower foragequality) occur due to microbial activity.Although numerous bacteria arepresent in hay, fungi account for mostof the microbial growth.Heating of hay is related to moisturecontent. Peak temperature is oftenreached within a week after baling, butwith higher moisture hay and conditionswhich limit heat escape, it maytake as much as three weeks. At safemoisture levels (less than: 20% forrectangular bales; 18% for round bales;and 16% for large rectangular packages)inside storage losses are typicallyaround 5% of dry matter, but lossesseveral times higher have been reportedfor extremely moist hay.“Weathering” (the term which iscommonly used to refer to the effects2which climatic conditions have on hay)is partially a physical process. Some ofthe dry matter loss which occursduring outside storage is caused byleaching, which refers to the dissolvingand removal of nutrients by the passageof rain water over the surface of, andthrough, the bale. The more digestiblenutrients are, the more soluble theyare, and thus the more likely they areto be removed by leaching.The switch from small rectangularbales to large round bales on most U.S.farms has resulted in higher storagelosses (in many cases, several timeshigher). Round bales are not inherentlysubject to greater losses, but they aremuch more likely to be subjected toadverse storage conditions, oftenremaining outside with no protectionbetween baling and feeding. Feedinglosses are usually sharply higher withround bales as well, partly because biground bales are generally fed on sodwhile rectangular bales are often fedin bunks.The extent of weathering damageduring outside storage varies mainlywith climatic factors and with foragespecies. Weathering primarily affectshay in the outside circumference of alarge round bale rather than in theends. Consequently, package size(mainly the diameter) affects theproportion of the bale contained in thesurface layer, and thus the magnitudeof losses (Figure 1).Figure 1. Dry matter loss vs. average spoilage depth inround bales of various diameters.*50%40%30%20%10%0%Bale diameter = 3 ft.4 ft.5 ft.6 ft.1 2 3 4 5 6Average spoilage depth (inches)*SOURCE: Buckmaster, D.R., 1993. Evaluator for RoundHay Bale Storage. J. Prod. Agric., 6:378-385.