Losses during curing cannot be eliminated. Cut hay when good drying weather is expected and respiration losses will be reduced considerably. After the moisture content of hay declines below 35 to 40%, most harvest losses are due to weathering and handling. Losses due to leaching increase with the number of rain showers, amount of rain, and the dryness of the hay. Leaching can cause yield losses as high as 20%, mostly as digestible soluble nutrients.
Carbohydrates, B vitamins, and some soluble minerals, such as potassium, are readily leached from dry hay. Rain not only leaches nutrients, it can also increase leaf loss due to the extra handling needed to dry the hay. Leaves are the most valuable part of the hay since they have the highest quality. Therefore, losing leaves can be very expensive. Windrower machines eliminate raking and thus leaf loss due to raking. Because drying takes longer in the windrow than in the swath, respiration losses and increased potential of rain may reduce this advantage in humid areas. Condition freshly cut forage, especially legumes, to allow the plants to dry more rapidly, thus reducing respiration losses and weather hazards.
Storage is probably where most beef producers in southern Illinois have the greatest loss of hay. Weathering reduces the dry weight of hay and changes its composition. Weathering lowers the feeding value of hay 15 to 25%, in addition to any dry matter losses. Weathering losses are greatly influenced by climatic variables; higher rainfall and more humid conditions cause more loss than drier climates.
Remember weathering occurs not only on the tops and sides of hay stored outside, but also where hay contacts moist ground. Research in Indiana has shown that storing bales on crushed rock versus the ground reduced the weathered portion from 23 to 11% of the original bale weight. Thus, outdoor storage losses can be lowered if hay is stored on a well-drained site. Also be sure the bale is dense and evenly formed which allows rainfall to run off rather than settle in depressions and soak into the stack. Round bales can be butted end-to-end with little increase in loss from storage. Do not stack round bales unless they are covered with plastic.
Even the best (shed or covered) storage conditions allow about 5% of the hay's dry matter to be lost after one year. Most nutrients maintain nearly constant concentrations when hay is properly stored, although carotene (provitamin A) concentration declines rapidly. Losses of dry matter and quality during storage can be considerable when hay is stored too wet. These losses are caused mostly by heating, which will usually occur if hay is packaged above 20 to 22% moisture. Grass hay can be packaged at a slightly higher moisture content than hay containing legumes.
A recommendation given often to reduce feeding loss is to use bale rings when feeding large round bales. This was clearly documented by South Dakota State University. Their three year study included 3- to 10-year-old cows allocated to three treatment groups. The hay was either rolled out on the ground, fed in a windrow using a bale processor or fed in a tapered-cone round bale feeder. Gestating cows were fed an average 58 days to document feed waste, cow performance (weight gain, ultrasound fat depth change, body condition score change and hay intake), labor inputs, and feeding time, which were subsequently used to develop an economic analysis.
Hay required per cow was based on a dry matter intake equation which took into account cow body weight and net energy maintenance requirement. Cows in the cone bale feeder treatment had an increased ending weight, backfat depth and body condition score, but decreased hay consumption when compared to other treatments. Hay quality between treatments was similar. In this study, feeding method not only influenced the amount of hay fed, but cow performance as well.
How? When hay is fed on the ground, a certain amount will be spread around and leaves will be shattered and trampled, leaving stems. The leaves of any plant have the highest levels of protein and energy, so we inadvertently lower the quality intake of the cattle. When this data was put into an economic model, the tapered-cone feeder lowered equipment cost, feeding time and overall wintering cost. Other studies have shown feeding losses as high as 45% when hay is fed on the ground versus in some type of restrictive feeding method. This loss would also include animal refusal due to other factors such as spoilage.
A study conducted at Michigan State University evaluated the quantity of hay loss and feeding behaviors from different round bale feeders. Cows were allotted pens with four feeder designs: cone, ring, trailer, or cradle. At the end of a 7-d period, each feeder type was assigned to a different pen for a second 7-d period. Feeder access, occupancy rate, and occurrence of agonistic (combative) interactions were recorded.
Dry matter hay waste was 3.5, 6.1, 11.4, and 14.6% for the cone, ring, trailer, and cradle feeders, respectively. Cows feeding from the cradle feeder had nearly three times the agonistic interactions and four times the frequency of entrances compared to cows feeding from the other feeder types. Feed losses were positively correlated with agonistic interactions, frequency of regular and irregular entrances, and feeder occupancy rate.
Another consideration, after ruminating on this data, is the ability of smaller cows and heifers to access hay to meet their nutritional needs depending on the type of feeder you have. Cradle feeders may result in those smaller cows and heifers losing condition and affecting their performance since they would be experiencing more agnostic behaviors and spending less time eating but more time moving to and from the feeders.
Regardless of whether you have sufficient hay supplies this year, you may still want to evaluate your hay loss and determine if there are ways to reduce hay waste. Reducing hay waste will also save you money. The data supports the use of round bale feeders to reduce hay waste; the amount of reduction will vary by type. Round bale feeders can also help maintain the quality of hay during feeding by protecting it from trampling, which can in turn influence cow performance. Remember good management will always pay.