The current feed and milk market volatility can make one’s head spin. Grain and forage prices are rising, and this can negatively affect income over feed cost and the breakeven cost of production.
Starch is a major nutrient in dairy rations, and it also can be expensive. There are some basic guidelines that are worth reviewing, especially when trying to keep feed costs under control and to optimize animal performance.
Making corn work better
Of all the cereal grains, corn is the most widely fed, either as shelled or ear corn — the latter of which is comprised of 20% to 25% cob and 70% to 80% grain, if partitioned by weight.
The energy that cereal grains supply comes in the form of starch with minimal levels of fats and sugars. The availability and rate of digestion of starch is heavily influenced by the processing method.
Starch in finely ground corn is degraded more rapidly by ruminal microorganisms than coarsely processed grain. Finely ground grains are higher in digestibility because there is more surface area where the rumen bacteria can attach.
The starch in high-moisture grain ferments more rapidly in the rumen than starch in dry grain. Heating grains, such as steam flaking — 24 to 28 pounds a bushel — enhances starch digestion. The heating process gelatinizes the starch in a manner that increases fermentability in the rumen.
Typically, processing grains adds to your expenses, so before you do it, ask yourself this question: Is the processing really necessary to complement the forage ration?
Ration starch levels
Several factors should be considered when determining the ration starch level. These include forage particle size, frequency of grain feeding, site of starch digestion, fiber digestibility, use of byproduct feeds, grain processing method and dry matter intake.
The following are guidelines for starch feeding of lactating cows, on a dry matter basis:
23% to 26%. Barley, oats, high-moisture grain, steam-flaked grain or finely ground grain can predominate the concentrate portion of the diet.
27% to 29%. High-quality hay forages predominate the ration. Corn silage also can predominate the ration with inclusion of non-forage fiber sources.
Greater than 30%. Coarsely processed corn is recommended with non-forage fiber sources.
Check the bottom line
There has been a trend over the past years to formulate diets with high starch levels that also are highly digestible. This approach has been common in heavy corn silage-based diets.
However, herd dynamics such as long days in milk, and number of first- and second-lactation animals, can be negatively affected by high-starch diets. Depressed milk components, reduced chewing activity, laminitis, inconsistent dry matter intake, and milk production not meeting the benchmarks for twice and three times daily milking may warrant reassessing the starch feeding strategy.
There have been several published research papers showing the positives of feeding a low-starch diet. A lot depends on the forage base and other ingredients being fed.
However, if animal performance is not meeting the minimum metrics on a high-starch ration, then it may be time to consider an alternative approach. This adjustment could have a positive effect on income over feed cost during times of increasing grain prices.
Monitoring must include an economic component to determine if a management strategy is working or not. For the lactating cows, income over feed cost is a good way to check that feed costs are in line for the level of milk production.
Ishler is a dairy Extension educator with Penn State Cooperative Extension.