How Much Corn Will It Take to Replace 10pds of Hay on a Beef Cow

Hay is the most common feed used for beef cows during winter time. However, U.S. hay production has been fluctuating for the last 20 years, and production has been below average since 2011 (Figure 1). Simple supply and demand economics mean that when there is a decrease in hay available, the price will increase.

Figure 1. Hay production in the United States over the last 20 years (USDA, 2018).

In Pennsylvania, when pasture is managed well in the fall, cows should be able to graze until mid- to early November. If forages are stockpiled, cows may even be able to graze through December in a typical year. However, if there is a frost or snow early, additional winter feed will be needed for the cow herd. Regardless of timing, winter feed is the greatest expense in a cow-calf operation. In 2012, with the drought and weather changes in Pennsylvania, hay shortages pushed prices to $400 to $500 per ton. The need for additional winter feed increased cost of production. In order to manage winter feed cost in times of economic crisis, beef producers, especially in cow-calf operations, need to be aware of alternative feed sources to mitigate winter feed costs.

Nutrient Requirements of Cows

Before we start talking about alternative feed sources, we need to understand cow nutrient requirements. Nutrient requirements depend on cow body weight, milk production potential, and lactation status (lactating or dry). Nutrient requirements of the gestating, dry cow from mid to late gestation are presented for discussion (Table 1). The mid and last third of gestation tend to coincide with winter feeding needs of most spring-calving herds in the Northeastern US.

Table 1. Nutrient requirements for non-lactating beef cows weighing 1,000, 1,200, or 1,400 lbs.

Nutrients	Cow weight	5 Months prior to calving	4 Months prior to calving	3 Months prior to calving	2 Months prior to calving	1 Month prior to calving
DM intake, lbs/d	1000 lb.	19.8	20.3	20.9	21.0	21.4
TDN, lbs/d	1000 lb.	9.5	9.9	10.4	11.2	12.2
CP, lbs/d	1000 lb.	1.33	1.40	1.48	1.64	1.88
DM intake, lbs/d	1200 lb.	22.7	23.3	23.9	24.1	24.6
TDN, lbs/d	1200 lb.	10.9	11.4	12.0	12.8	14.0
CP, lbs/d	1200 lb.	1.54	1.61	1.72	1.90	2.19
DM intake, lbs/d	1400 lb.	25.5	26.2	26.8	27.0	27.6
TDN, lbs/d	1400 lb.	12.3	12.8	14.2	14.4	15.8
CP, lbs/d	1400 lb.	1.73	1.81	1.93	2.13	2.46

Adapted from Beef NRC (1996).
Intake and nutrient concentrations are expressed on a dry matter basis.

This scenario shows that heavier cows will require more nutrients than lighter cows. In addition, nutrient requirements increase as the cow nears parturition or calving. These increases closer to calving occur because the fetus grows most rapidly in the final 3 months leading up to parturition.

Based on the average nutrient concentrations in hay across the US (Table 2), in some conditions, feeding hay alone may meet nutrient requirements of the mature beef cow in mid-gestation. However, when hay is limited, of poor quality, or simply too expensive, producers may consider alternatives. Corn, for example, can be substituted for hay as the primary energy source in mature cow rations.

Table 2. Range of nutrient concentrations of hay fed to cattle

Item	Range
Dry Matter, %	88-90
TDN, %	54-60
Crude Protein, %	6-9
NDF, %	70-74
ADF, %	38-42
Ca, %	0.3-0.6
P, %	0.1-0.2

Corn is commonly used as a feed in finishing, or feedlot, cattle diets throughout the U.S. Whole corn-based diets can meet the nutrient requirements of pregnant beef cattle without adverse effects on production and, depending on the economics, may be provided at a lower cost than feeding hay (Loerch, 1996). Because corn is much more energy-dense than hay (Table 3), intake of corn must be restricted so cows do not get fat. This can be done by putting cows on a limit-fed corn-based diet. By limit feeding, cows are not able to eat all that they "want", but rather are provided with just enough to meet their nutrient requirements. In general, a mature cow will require about 1 lb of whole kernel corn for every 2 lbs of hay she was eating. From an economic standpoint then, if hay is $160 per ton and corn is $4.50 per bushel, the corn is a better buy from an energy standpoint because they are roughly the same price per ton but your cows need half as much corn as they do hay.

Table 3. Nutrient concentrations of corn grain

Item	Average
Dry Matter, %	88.0
TDN, %	87.6
Crude Protein, %	8.8
NDF, %	9.7
ADF, %	3.6
Ca, %	0.03
P, %	0.3

While corn is energy-dense, it contains relatively little protein. Therefore, in order to meet protein requirements of the pregnant cow fed corn grain, protein supplements must be included in the diet. Supplements for protein can carry minerals and vitamins as well. In addition, supplements in the limit-feeding scenario should include an ionophore to prevent ruminal acidosis in cows. Keep in mind that ionophores should not be fed free-choice so they must be fed daily as part of the total ration.

Limit-feeding whole kernel corn is a great alternative in times of poor hay quality or when hay is too expensive. However, cows should still be given some hay. It is best to feed cows 2 to 6 lbs of hay per day. If weighing hay is problematic, consider simply limiting the cow's access to hay to about 2 to 4 hours per day by gating off the feeding area. Either limiting access or restricting the pounds fed per day will reduce hay use by the cows and, potentially, save money.

Example Scenario

In 2007, Loerch suggested a diet of 5 lbs of first cutting hay, 2 lbs of supplement and 12 lbs of whole kernel corn (per cow basis). The following recommendations were made for that diet scenario:

Table 4. Example of supplement for cows limit-fed corn grain

	%
Ground corn	32.1
Soybean meal	45.6
Urea	4.1
Limestone	7.8
Dicalcium phosphate	4.3
Trace mineral salt	3.2
Dyna K	2.3
Selenium premix (200 ppm)	0.4
Vitamin premix (Vit A, 15,000 IU/gram; Vitamin D, 1,500 IU/gram)	0.2
Rumensin 80 (192 mg Rumensin/hd/d)	0.12

Note: This supplement contains the following nutrients: Crude protein, 36%; Calcium, 3.76%; Phosphorus, 1.00%. If using a commercial supplement, feed according to bag instructions.
Adapted from Loerch, 2007

1. The protein and mineral supplement should be similar to that used for feedlot cattle fed a grain-based diet (Table 4).
2. Feed whole kernel corn. Whole corn will be consumed and digested more slowly than processed grain. This reduces the risk of acidosis and other metabolic disorders.
3. Adjust corn intake to achieve desired weight and/or body condition score. Cows will need to consume about 1% of their body weight during cold winter months and as they enter lactation.
4. When starting the program, take 7 to 10 days to adjust cows to the corn-based diet. Do this by adjusting up the corn and decreasing hay to the 5 lbs level. Make sure bunk space is adequate (at least 30 inches per cow) to ensure that all cows have an opportunity to eat the limited feed that will be provided. Keep cows in a securely fenced area.
5. Example of how to begin the limit-feeding program:

Day 1 and 2: Feed 4 lbs whole shelled corn + 2 lbs supplement + 12 lbs hay

Day 3 and 4: Feed 6 lbs corn + 2 lbs supplement + 8 lbs hay

Day 5 and 6: Feed 8 lbs corn + 2 lbs supplement + 5 lbs hay

Day 7 and 8: Feed 10 lbs corn + 2 lbs supplement + 5 lbs hay

After day 8: Feed 12 lbs corn + 2 lbs supplement + 5 lbs hay; adjust amount of corn offered based on cow body condition, weather conditions, and pre- and post-calving needs. Adjust up or down 2 lbs of corn per cow if cows are getting too thin or too fat.

The supplement should be 30 to 40% protein (and urea can be used), 4 to 5% Calcium, and should contain Rumensin or Bovatec (to prevent ruminal acidosis). Hay quality is not important in the limit-feeding scenario. In fact, straw, corn stalks, or poor quality first cutting hay are fine. As a reminder, at least 2 lbs of hay should always be fed to prevent ruminal acidosis.

Because corn is the most readily available source of supplemental energy in many areas, it was used as an example here. However, it should be noted that cows may be wintered on corn gluten feed, distillers' grains, or other byproducts as well. Work with your nutritionist or your extension specialist to determine the best feed to use in your own scenario. Price your feeds based on the energy that they supply relative to hay and make your purchasing and feeding decisions based on the best economic outcome for the farm.

Conclusion

Winter feed costs typically represent the largest portion of a cow/calf operation expenses. In time of limited hay supply and increased hay price, it can be economically advantageous to use corn rather than hay to meet the energy requirements of cows. Pasture scarcity, short supplies of harvested forage, and increasing hay prices are opportunities to consider wintering cows feeding alternative energy sources to hay. Because corn is the most readily available source of supplemental energy in many areas, limit feeding a corn-based diet can be a cost-effective option for meeting the nutrient requirements of beef cows.

References

Loerch S. C. 1996. Limit-feeding corn as an alternative to hay for gestating beef cows. J. Anim. Sci. 74:1211–1216.

Loerch S. C. 2007. Corn as an Alternative to Hay for Gestating and Lactating Beef Cows. Ohio Beef Cattle Letter. Ohio State University. Extension Beef Team.

National Research Council. 1996. Nutrient Requirements for Beef Cattle. The National Academies Press. Washington, DC.

USDA. 2018. NASS.USDA.GOV. Agricultural Counts. Statistics by Subject. National Statistics for Hay.

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Source: https://extension.psu.edu/consider-corn-based-diets-as-alternatives-to-hay-for-beef-cows

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