Maurice L. Eastridge, Professor and Extension Dairy Specialist, The Ohio State University
With the drought situation this year and the variable amount of rainfall in different areas of Ohio, corn silage will be harvested ranging from no ears to being well-eared. Information elsewhere in this issue of Buckeye Dairy News provides guidelines to follow for proper harvesting and pricing of corn with different stages of development. The focus of this article will be on using alternative ingredients in situations of feeding corn with no ears to being well eared. Even with well-eared corn for silage, the cost of corn grain may result in favorable substitution of some alternative ingredients. Although there is no neutral detergent fiber (NDF) or starch requirement for dairy cattle, both of these dietary components are important for maintaining favorable rumen fermentation and optimizing microbial protein synthesis. Inadequate or excessive amounts of either NDF or starch can cause adverse issues. Although typical diets for lactating cows generally contain 25 to 35% starch, the cost of corn has caused us to re-examine the amount of starch in the diet. In general, dropping below 20% starch in the diet may compromise the microbial fermentation. Lack of ear on corn will result in high NDF corn silage, which can cause a reduction in intake if dietary NDF gets too high, e.g. in excess of 25% forage NDF in the diet.
A list of ingredients is provided in Table 1 of some commonly traded commodities that may be priced adequately at certain times for inclusion in dairy diets to provide protein, starch, and/or fiber. A few of the carbohydrate ingredients can be used to supply some starch in the diet (e.g. hominy), but most of them provide primarily nonforage fiber (NFNDF), and as a result, appreciable amounts of some nutrients, such as protein, are provided. The NFNDF can be used to dilute some starch in diets, e.g. feeding a lot of well-eared corn silage or trying to limit the inclusion of high-priced corn. Some of the FNDF can be replaced with the fiber from some of these ingredients (e.g. feeding a lot of corn silage with no ears) and NFNDF sources are useful in diluting starch when forage availability is low, but in general, the lower limit is 16% FNDF in a diet. This lower limit is determined by the concentration of starch in the diet, degradability of the starch source, and particle size of the forages. When feeding diets low in starch, 2 to 3 % supplemental sugar (e.g. molasses or similar course) may improve ruminal fermentation and milk yield.
Overall cow health and income over feed costs need to be monitored continuously during these times of dietary changes and high feed costs. Short term advantages need to translate into long-term benefits.
Table 1. List of typical alternative carbohydrate and protein sources that may be useful in dairy cattle diets.
| Ingredient |
% CP
|
% Starch
|
% NDF
|
Upper Level (%)
|
| Carbohydrate Sources |
|
|
|
|
|
Brewers grains |
29.2
|
12.0
|
47.4
|
25
|
| Citrus pulp |
6.9
|
1.5
|
24.2
|
20
|
| Corn gluten feed |
23.8
|
18.0
|
35.5
|
30
|
| Cottonseed1 |
23.5
|
0.3
|
50.3
|
15
|
| Hominy |
11.9
|
45.0
|
21.1
|
40
|
| Distillers grains2 |
29.7
|
6.0
|
38.8
|
25
|
| Soybean meal |
13.9
|
5.3
|
60.3
|
30
|
| Wheat middlings |
18.5
|
30.0
|
36.7
|
25
|
|
|
|
|
|
|
| Protein Sources |
37.8
|
0.0
|
29.8
|
10
|
| Canola meal |
65.0
|
15.6
|
11.1
|
10
|
| Cottonseed meal1 |
44.9
|
1.5
|
30.8
|
10
|
| Feather meal |
85.0
|
0.0
|
0.0
|
5
|
| Meat meal |
54.2
|
0.0
|
0.0
|
5
|
1Limit the amount of cottonseed and cottonseed meal in the diet due to the additive amount of gossypol contributed. The amount
of cottonseed included alone is limited because of its concentration of unsaturated fat (~20%).
2The composition of distillers grains can be quite variable, depending if it is coming from a whiskey or ethanol plant and if it is a fractioned
product (e.g., high or low fiber).