Feed costs are a large part of livestock producer’s expenditures. The alternative of either growing or buying quality hay is important to producers as well. Adequate hay storage therefore is critical so producers can minimize the loss in both value and nutrients of their hay. Stored forages provide essential nutrients primarily in winter or when pastures are inadequate and are a consistent feed supply for livestock. However, some of these nutrients can be lost if forages are not stored properly.

Types of Storage Losses

Table 1. Different types of hay storage and the percent of loss

Type of Storage

Percent Loss (%)

Hay Barn


Stacked and Tarped on Tires or Pallets


Plastic Sleeve


Net Wrap


Outside Uncovered


**Data is from study conducted at the University of Tennessee1

Table 1 shows some of the different types of hay storage available and the percentage of expected losses between nine months and one year. Hay stored in a barn could have around a 5% loss, whereas, that stored outside uncovered could have 30% losses due to spoilage.

Barn-stored hay usually has higher nutritional value and little spoilage compared to that stored outside. Hay stored inside allows for a reduction in contact with soil and moisture thus reducing spoilage. Some disadvantages of indoor storage are unwelcome animals, such as skunks, raccoons, and other animals. Storage space is limited, and bales must be stored carefully to prevent falling or exerting too much pressure on the sides of the barn. There is also the initial investment in building the storage barn to consider.

One of the advantages of storing bales outside is the increased amount of storage space available. Some disadvantages of storing bales outdoors are potential spoilage, and decreased nutritional value. To avoid spoilage it is best to store hay outdoors on gravel or pallets end to end in north-south rows. Outdoor hay storage areas should ideally not be in a flood plain and with as little shade as possible, to prevent spoilage. It is important for producers to remember hay must have proper drainage, sunlight penetration and airflow between rows to facilitate drying. Hay bales left uncovered can lose 5-20% of its original weight to dry matter losses in nine months. Elevating bales reduces losses by 3-15%. If a producer does not have a barn available to store hay the best option is to cover and elevate the hay. By elevating and covering the hay, the maximum loss could be 2-4%, which is similar to barn-stored hay.

Table 2 shows the percentage by volume of round bales according to the inches of weathering present. Weathering on the outside of round bales (a few inches) accounts for a large portion of the total bale.

Table 2. Percentage of bale volume affected by weathering.



Depth of weathered layer in inches

Bale Dimensions







% of bale volume weathered




















For hay bales stored outside weathering is normal. It is important to try and feed outside stored bales within nine months because of their loss in nutritive value. Producers will typically store higher value hay in barns and lower value outside. Producers need to feed hay based on meeting their animals nutrient needs, and use the storage method which best accommodate these.

Let’s determine for example the costs of different hay storage methods of a producer with 100 heads of cows averaging 1300 lbs. This producer calculates he will be feeding cows two percent of their body weight as hay or 30 lbs./head/day. The producer has a 150 day feeding period, which means he needs a total of 225 tons of dry matter. The producer decides to buy 5’x4’ bales which weigh 1,000 lbs. each. Assuming the alfalfa/grass hay is 90% dry matter he will need 2502 tons or 500 bales to meet the herd dry matter requirements.

It is important to calculate the costs associated with storage loss depending on the storage system. The cost of the alfalfa/grass hay the producer is $85/ton. The initial cost of 250 tons of hay is $21,250. Table 2 shows the different methods of hay storage and the additional hay needed to meet the producers feeding requirements.

Table 3. Additional hay needed and associated costs






Compared to:


Additional Hay Required (tons)

Added Hay Cost


Tarped  on Tires & Pallets








Hay Barn







Stacked & Tarped
on Tires or Pallets







Plastic Sleeve







Net Wrap







Outside Uncovered








Table 3 shows the additional hay need and the costs based on the expected spoilage rates. This table also shows the cost differences between storing hay in a barn compared to the alternatives. Because of its low quality losses storing hay in a barn is the best solution available. However, this is not always a feasible option for some producers then we can look at the other options and see that stacked with a tarp and on tires or pallets is the next best alternative when comparing the differences in the additional cost. According to Table 3 the best long term solution for the producer would be to invest in a barn for hay storage, however it’s not always feasible for producers. No matter what type of storage is being used, dry matter losses are always possible. By following the recommended storage methods, and careful handling, losses can be minimized saving livestock producer’s money.

1At the time this article was written there is no known data on the dry matter loss from South Dakota, there have been other states that have conducted similar studies on dry matter loss and the numbers appear similar.

2To calculate actual tons needed and accounting for moisture content we multiply the original number divided the percent of dry matter. In this case 225/0.90=250 tons.