Conversations: Ask your nutritionist about forage consistency

Feed ingredients and forages can be nutritionally volatile, creating significant starch variation in a dairy ration. As producers and their advisors meet in the conference room (or kitchen), the conversation should lead to a better understanding of this volatility, and how managing it can greatly improve the efficiency of a ration.

By Kevin Leahy

The stability of a herd’s ration directly affects milk production stability and efficiency. Here are some questions dairy producers should consider when evaluating ration consistency, and discuss with their herd nutritionist to consider options to improve the consistency.

1) What are some of the causes of nutritional volatility in a ration?

Nutritional volatility in a ration can be caused by a number of things. Some of the main causes can be a change in the type of feed ingredients being used, the harvest/storage/fermentation of forages included, and even the genetics of the forage crop. Often, these variations can be extreme even within the same bunker or truckload of feed, further adding to the volatility. Forage and feedstuff starch digestibility can vary greatly in both the speed of which it is digested, and where – specifically – in the digestive tract it is broken down. The key is knowing how to manage these differences to reduce negative “volatile” effects.

Consider factors that could change content within a ration. Ask your nutritionist if more frequent tests of ration content would be beneficial.

2) Are there signs that might indicate there is a challenge in a particular ration?

Yes, there can be many signs of trouble. The real challenge is realizing that it is in the ration, and doing so soon enough to avoid a train-wreck. One of the more common, short-term signs may include abnormal fluctuations in herd production – especially in butterfat composition of the milk. Longer-term effects might cause reduced reproductive performance. Unfortunately, the latter often occurs long after the problem began.

Carefully review milk component and production fluctuations and work with your nutritionist to evaluate how these may align with forage input changes in the ration.

3) What options are there for measuring starch content of a ration?

Measuring starch content in a ration has been an important step for nutritionists to evaluate inputs to a ration. Measuring crude – or total tract starch digestibility – can be done very effectively by sending feed samples in to a laboratory. These tests indicate the total amount of starch digested in the rumen and the lower gastrointestinal tract. More recently, we have gained technology allowing a nutritionist to test and balance starch content digested specifically  in the rumen.

Ask your nutritionist for the latest insight and advice on various starch measurements.

4) How should test results and insights be used?

Knowing the starch content and expected speed of digestibility in the rumen is important, because of the potential effect on rumen parameters. For example, pH and the digestibility of other nutrients – and the resulting effect on milk production and component yield – can help guide ration balancing decisions that will allow for more optimal nutrient management. This may even help identify ways ration ingredient costs can be reduced or substituted with less expensive inputs, without sacrificing the nutrition needs for production goals.

Spend time with your nutritionist carefully evaluating your herd performance goals, and how ration changes might help achieve them – while still improving economic efficiency.

5) What can a producer expect as a result of more precisely managed starch?

When rations can be calculated to maintain optimum starch digestibility, improved feed efficiency and stable milk production can be more easily attained. From an efficiency perspective, rations can be developed that maximize production without wasting expensive starch sources, like corn. Or, alternative, less-costly feed ingredient options can be considered if you know what their digestible rumen starch might be, and how the ration consistency can be maintained.

Explore your options for various feed ingredients to help reduce ration cost. Working closely with your nutritionist to better understand rumen starch digestibility might help identify alternative, convenient and less-costly options that would allow you to maximize production goals and further minimize feed costs.


Kevin Leahy is technical services manager for Calibrate™ technologies.  Contact him via phone at 877-595-1361or e-mail:

Miss a 2010 Conversation?

Find these ‘Conservations’ columns at

• January: Direct-fed microbials

• February: Lagoon management

• March: Corn silage quality

• April: BVD management

• May: Heifer management

• June: Udder health

• July: Pregnancy detection

• August: A TMR audit

• September: Transition cow nutrition and management

• October: Alfalfa seed selection

• November: Energy status at transition