Cows can utilize a wide variety of feedstuffs as long as the ration is palatable and balanced for the cow’s needs and genetic potential. Several decades of experience with a drylot beef cow herd at the NDSU Carrington Research Extension Center has validated the concept that a balanced ration formulated to meet the cows’ needs supports healthy and productive animals with excellent reproductive performance.
Corn grown for silage produces more energy per acre than any other crop. Corn silage is very palatable and conditions a ration with other ingredients. Alfalfa is excellent forage as haylage or dry hay and provides protein, energy and minerals. Nondairy-quality alfalfa or mixed grass-alfalfa forages should be fed at economic and nutritionally appropriate levels.
A wide variety of feeds can be used for drylot cows. Consider cost per unit of protein and/or energy in purchasing and feeding these ingredients and include transportation and storage losses.
Most all crop residues, Conservation Reserve Program hay, ditch hay, slough hay and other low-quality forages can be used in drylot diets when properly supplemented. Forages that are very low in quality or digestibility should be used sparingly in cow rations because rumen impaction can occur. This is especially true when these low-quality forages are chopped and included at higher proportions of a dry diet. Table 1 shows example rations for lactating beef cows, with Ration 1 having been used successfully for cows of average milking ability at the NDSU Carrington Research Extension Center Livestock Unit.
If 100% hay rations are considered, analysis for protein and energy are critical. Grain and other supplemental energy or protein can be fed to make up any shortage of nutrients. Distillers grains with solubles are commonly used in cow rations. Rations 5 and 6 provide example diets with ethanol coproducts. Condensed distillers solubles, a liquid coproduct, are useful when mixed with low-quality forage and are an excellent ration conditioner.
The amount of mineral supplied in the diet will vary with feeds included in the ration. As a general recommendation, cows should be provided with trace mineral salt and a calcium (Ca)-phosphorus (P) mineral supplement to achieve a Ca-to-P ratio of 1.5-to-1 in the entire diet. The use of distillers coproducts or grains may eliminate the need for a phosphorus supplement.
A mineral mix can be fed free choice, but mixing it in the ration ensures more uniform intake. Cows fed high volumes of crop residue may require more careful mineral supplementation because crop residues tend to be lower in minerals, compared with other forages such as alfalfa or grass hay. Give special consideration to mineral supplementation if deficiencies or toxicity problems are known.
With the increased use of distiller grains with solubles in beef cow rations, fat and sulfur levels should be monitored closely. The maximum sulfur (S) level ranges from 0.3% to 0.5%, according to the National Academies of Science, Engineering, and Medicine Nutrient Requirements of Beef Cattle (2016).
At the low end of the range (0.3%) are high- concentrate diets that result in greater production of hydrogen sulfide gas in the rumen, compared with forage-based diets. Diets for cows may approach the 0.5% maximum level because these diets generally contain much greater levels of forage or roughage.
The calculation of dietary S intake must include S present in the feed and the water. In some areas, high- sulfate water may contribute the majority of the S intake for beef cattle.
Excess dietary S can be a problem for ruminants for two reasons. First, high levels of sulfur (above 0.3% to 0.5% of diet dry matter) from feed and water can lead to polioencephalomalacia (PEM). Second, sulfur interferes with copper absorption/metabolism. Producers in areas with suspected high sulfate in the water should test their water.
Table 2 provides examples of various inclusion rates and sulfur contents for distillers grains with solubles and the impact on overall dietary S content in a corn- and corn silage-based diet. Notice the table has several situations that are close to or above the suggested maximum level of sulfur in the diet. The table is for example purposes only. Producers are encouraged to work with a nutritionist to formulate diets with appropriate S content for their production environments.
The fat or oil content of cattle diets should not exceed 5% to 6% of dry-matter intake. Ethanol coproducts such as distillers grains plus solubles and condensed distillers solubles, as well as oilseeds such as sunflower, soybean and canola, are high in oil content. Diets with greater than 6% oil or fat content can have detrimental effects on fiber utilization. Consequently, take care when formulating diets containing these feedstuffs.
Table 1. Rations for Lactating Beef Cows in Drylot (Percent As Fed).
Ingredient
|
Ration 1
|
Ration 2
|
Ration 3
|
Ration 4
|
Ration 5
|
Ration 6
|
These diet formulations should be considered examples of upper limits of distillers grains with solubles and also assume relatively lower levels of fat and sulfur in the coproduct used.
|
Corn silage (35% DM)
|
70
|
78
|
-
|
-
|
-
|
-
|
Alfalfa-grass hay (15% CP)
|
30
|
-
|
80
|
18
|
-
|
-
|
Sunflower meal (39% CP)
|
-
|
12
|
-
|
-
|
-
|
-
|
Grass hay (11% CP)
|
-
|
-
|
-
|
-
|
40
|
-
|
Straw or stover
|
-
|
10
|
20
|
32
|
23
|
36
|
Wheat midds
|
-
|
-
|
-
|
50
|
-
|
-
|
Dry distillers grains w/solubles
|
-
|
-
|
-
|
-
|
37a
|
-
|
Wet distillers grains w/solubles
|
-
|
-
|
-
|
-
|
-
|
64a
|
Table 2. Sulfur Content Scenarios for Beef Cow Diets.
Inclusion rate,
% DM
|
Sulfur Content of Distillers Grains
|
.60%
|
.80%
|
1%
|
20
|
.21
|
.25
|
.29
|
30
|
.27
|
.33
|
.37
|
40
|
.33
|
.41
|
.49
|