Cattle prices are down compared to last year; however, producers are still enjoying the second highest market ever. This decrease in cattle prices is causing producers to consider opportunities to reduce input costs. Feed is the largest portion of annual cow costs, thus it makes sense to consider cutting, if possible. However, it is key to develop a strategy to carefully reduce costs without negatively impacting production.

Managing feed costs is more than developing a least cost ration. Delivering the correct amount of each feedstuff is needed to supply the proper diet. Additionally, management of stored feeds to reduce spoilage and waste is critical when managing feed costs.

Evaluating Feed Losses

Harvested feeds are “normally” stored in the fall for feeding during the winter months. So why should producers think about stored feeds now? This is an excellent time to evaluate the amount of losses that are occurring with the present storage system and develop ideas for better storage opportunities to reduce spoilage.

According to a survey conducted in Kansas, 72% of producers use large round bales. In South Dakota this percentage would be similar, if not higher. Large round bales are one of the most economical hay production systems due to its low labor requirements. Unfortunately, because of their bulk, they are often stored outdoors and susceptible to weathering. What is the depth of the weathered layer on the bale? A four-inch weathered layer on a six foot bale represents 21% dry matter loss (Table 1). Assume home-produced hay costs $60 per ton, a 20% loss (Table 2) is $12 per ton. A 1,300-pound cow would consume about 35 pounds of dry hay per day. Over a 120-day feeding period she would need in excess of 2 tons of hay (35*120 = 4,200 pounds or 2.1 tons). Forage losses due to weathering would be $24 per cow per year or a very costly $4,800 for a 200-cow herd.

Table 1. Amount of dry matter in outer layers of large round bales.

Outer layer depth
Bale diameter, ft 2” 4” 6” 8”
------- % dry matter loss --------
4' 16 31 44 56
5' 13 25 36 46
6' 11 21 31 40
7' 9 18 27 34
8' 8 16 23 31

Table 2. Feed dollars lost in storage.

Hay price ($ per ton)
Storage loss (%) 40 60 80 100 120
5 2 3 4 5 6
10 4 6 8 10 12
15 6 9 12 15 18
20 8 12 16 20 24
25 10 15 20 25 30
30 12 18 24 30 36
35 14 21 28 35 42
40 16 24 32 40 48

Evaluating storage system that reduce spoilage start with proper harvest management. The key is making dense bale that help reduce moisture penetration. Bale wrapping method also influences moisture penetration, net wrap has been shown to reduce spoilage.

Storage Considerations

Hay in South Dakota is stored inside or outside, which includes covered versus uncovered, stacked versus one level, or various combinations. Dr. Hernandez, SDSU Extension Forages Field Specialist, describes proper hay storage to reduce spoiling and dry matter losses. However, the amount of storage space required to supply forage over the winter, may not make it feasible to store all hay inside. Producers need to develop strategies that will reduce spoilage and dry matter losses within practical limits.

Russell and Huhnke (1997) compared different protection techniques for hay stored outside or inside a barn (Table 3). A couple of trends reported with this data were that good drained surface and covering reduced dry matter losses. Drain-allowing surface with plastic cover as well as plastic sleeve had the lowest dry matter losses. It is worth noting that the digestibility of the dry matter was also impacted by the storage method. Hay stored on the ground without cover had a 12.7% difference compared to barn-stored hay. Note that minimizing ground contact reduces moisture wicking from the soil.

Table 3. Dry matter and digestible dry matter losses in barn-stored hay compared to outside with various protection techniques.

Increase with barn storage, % Units
Treatment compared to
barn storage
Dry matter
Digestible dry matter
On ground without cover
(3.6 – 14.5)
(3.3 – 17.2)
Drained surface
(rocks, pallets, etc.)
(-1.3 – 6.7)
(-0.4 – 13.4)
Plastic cover on bale tops
(0.6 – 4.6)
(2.9 – 4.3)
Drained surface + plastic cover
on bale tops
(0.9 – 2.9)
(-2.1 – 1.8)
Net wrap
(0.6 -1.5)
Plastic sleeve
(-1.4 – 2.7)
Pyramid stack + cover on top
Russell and Huhnke, 1997

The Bottom Line

Hay storage method does not change during the winter. Take time however, to evaluate the amount of the weathered layer on the bales as well as noting the amount of hay lost due to spoilage through the contact with the ground. The amount of forage not being fed can be substantial. Small investments into improving hay storage can increase the amount actually consumed by the animals and reduce the hay required to be harvested. If hay dry matter losses are 20%, a 1,300-pound cow fed 120 days of winter feeding would require 5,250 pounds of harvested hay to meet her nutrient requirements instead of 4,200 pounds of adequately harvested and stored hay.

If you have any questions regarding any of the concepts in this article or have any other production related questions do not hesitate to contact a SDSU Extension Beef Specialist or Cow/Calf Field Specialist.