Nutrient Variation – The Unwelcome Surprise

A key to preventing such surprises is to ensure the nutrients we are providing to the cow stay consistent. ( Lindsey Benne )

I am not a fan of surprises. Especially within a nutrition program on a dairy. If operating correctly, the diet which is balanced should result in the predicted outcome. Or at least close. However, surprises do happen, and we are left to solve the puzzle as to why the cows are performing contrary to what we expected. A key to preventing such surprises is to ensure the nutrients we are providing to the cow stay consistent. This may seem obvious, but often we use “book values” to approximate the nutrient content of the feeds in the ration. This results in a ration to which we can only guess the exact nutrient contents. There are several strategies to limit the nutrient variation of our rations. 

To start, forages need to be routinely analyzed. Forages, as we all know, can be extremely variable from year to year, bunker to bunker, and even within the face of the bunker. Thus, testing allows us to modify the ration with the most recent nutrient values. Forages also comprise a large portion of the diet. Therefore, any small change in the forage quality will greatly impact the nutrient content of the entire ration. This practice is well-adopted but needs to be emphasized. 

As we are starting to balance our rations with greater precision, there are lower-inclusion feedstuffs which will greatly impact nutrient levels in the diet. For example, soybean processing or bloodmeal drying can greatly impact the lysine content available to the cow. There are several ways to try to control for this variability. Simply, we can overfeed a nutrient to ensure we meet the animal requirements. If we are concerned the lysine-rich feeds, such as bloodmeal or soybeans, are variable, we can just balance for more lysine. This lowers the risk of being deficient of lysine but is not a cost-effective or efficient solution. 

Another option is to increase the number of feeds which provide a given nutrient. In this case, we hope the nutrient variation within feedstuffs cancel each other out and result in a more consistent ration. Let us use the roasted soybean and bloodmeal example, once more. If the roasted soybeans are roasted perfectly, they may provide a greater than expected amount of lysine. Whereas, if the bloodmeal was heat damaged, it may have a lower amount of available lysine. If we feed both, they may offset each other’s variation. The more feedstuffs which provide a nutrient, the more likely that nutrient will remain consistent in the ration. 

The best option may be to adopt a routine testing program to analyze more ingredients more often. Although sending samples for laboratory analysis is not free, the returns from improved ration balancing and cow performance can out-weigh the cost. To receive the biggest bang for your testing buck, start by testing those feeds which are known to be inconsistent, keep track of where these feeds are originating, and with time, we can precisely predict the nutrients in our ration. Hopefully with some extra attention, we will never have to suffer another unwelcome surprise. 

Trent Dado is consultant with GPS Dairy Consulting, LLC. GPS Dairy Consulting, LLC is a professional team of dairy nutrition consultants servicing dairies throughout the midwest and beyond. 

 
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