Harvested forages are a critical component of winter feeding programs for many of North Dakota's cattle herds.
"Conducting a hay inventory now will give producers a good idea of possible deficiencies and allow time to develop the best options for the upcoming feeding season," says Janna Block, North Dakota State University Extension livestock systems specialist based at the Hettinger Research Extension Center.
The first step is to get an accurate count or measurement of bales harvested. Bales should be grouped by lot, which is defined as similar species harvested from the same field within a 48-hour period.
Use a commercial scale to get a good estimate of bale weight by weighing several loads or multiple individual bales. Once weight is known, it is important to determine dry matter content of the bales because moisture affects weight but does not provide nutrients to the animal.
The dry matter of forages can be determined by using a Koster moisture tester or other electronic methods at home or by submitting a sample to a commercial laboratory for analysis. If the dry matter content of bales is unknown, an estimate of 85% to 90% can be used for the initial inventory estimate; however, laboratory analysis is recommended for ration balancing.
The second step is to estimate potential feed needs. A variety of factors influence how much forage a cow will eat every day. Body weight, stage of production and environmental factors will play a key role, in addition to forage quality.
Current numbers and estimated weights for each class of livestock (mature cows, bulls, heifers, yearlings, calves, etc.) to be fed this winter should be written down. An estimate of 2.5% of body weight can be used to determine dry matter forage requirements of each animal per day.
Here is an example:
- 175 mature cows × 1,350 pounds × 0.025 = 5,906 pounds of dry matter per day
- 8 bulls × 1,800 pounds × 0.025 = 360 pounds of dry matter per day
- 26 yearling heifers × 670 pounds × 0.025 = 436 pounds of dry matter per day
This herd would need 6,702 pounds of dry matter per day. If a producer typically feeds for 210 days, a total of 1,407,420 pounds, or 704 tons of hay on a dry matter basis would be needed. If bales weigh 1,400 pounds apiece and contain 88% dry matter, each bale would supply 1,232 pounds of dry matter (1,400 pounds x 0.88). For the above example, this means that around 6 bales would be required to meet feed needs per day, with a minimum of 1,260 bales required for the feeding period.
These calculations do not include the potential need for extra hay during cold winter weather. Storage and feeding losses also should be included in calculations to ensure that adequate hay supplies are available.
If the forage is stored outside, dry matter losses could be 20% or more. If stored inside, losses will decrease to around 7%.
Feeding losses vary depending on the feeding system. When hay is fed in bunks, waste may be as low as 3% to 14%. If bales are rolled out on the ground, losses due to trampling and overconsumption could be as high as 45%, particularly when cattle are fed for multiple days at one time. With free choice access to large quantities of forage, intake typically will increase by 15% to 20% beyond what is needed to meet requirements.
If conditions allow, daily feeding helps force cattle to eat hay that might otherwise be wasted. If hay costs $120 a ton and waste could be reduced by 25% by covering the hay and feeding on a daily basis, this would result in savings of more than $30 per ton. These savings could be used to invest in extra equipment such as feed bunks, a bale processor or feed wagon.
Assuming an overall loss of 15% using the above example, an additional 189 bales would be needed for the feeding period (1,260 bales x 1.15). Including this waste factor helps ensure that forage supplies will be adequate.
"Keep in mind that this estimate of feed needs does not consider differences in forage quality or specific nutrient requirements of cattle," says Block. "Completing the process described should help identify a potential forage shortage; however, actual amounts of forage (and possibly supplement) to be fed should be determined by utilizing laboratory analysis of forage and developing a balanced ration."
There are a number of spreadsheets and online tools available to estimate hay needs. For more information about conducting a forage inventory or developing a winter ration, contact your local NDSU Extension agent.
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