Maximize production, but don't waste resources. That sums up the art and science of formulating rations for milking groups. The challenge is that rations are seldom balanced for just one cow; they are balanced for a pen of cows with similar characteristics – age, days in milk, reproductive status, and even breed.

Bill Weiss from The Ohio State University presented our April webinar, "Target rations for your milking groups." He addressed basic principles and some misconceptions in balancing rations for lactating cows.

The goal is to provide ample nutrients for top producers to reach their potential because you do not want to shortchange the most efficient and profitable cows. Yet, feeding excess to those that will not take full advantage, such as late lactation cows, adds unnecessary feed cost.

Feeding all cows as if they were all top producers is expensive because many will not fully utilize the nutrients you make available. The other consideration is overfeeding nutrients, which may be excreted in urine and manure, that potentially could have negative environmental impacts.

The cows that should receive careful attention include recently fresh ones. Days in milk (DIM) affects dry matter intake (DMI). It takes about a month for a fresh cow to consume what she is fully capable of eating. So, when possible, wait about a month before introducing her to a pen of cows that are at peak feed intake and production.

Weiss defined the concept of "safety factors" when balancing rations. It is the degree of overfeeding relative to the pen's mean requirements.

Nutrition is not an exact science. So, you should feed for the above-average cow. But what repercussions could surface? How do you determine where to hold back? Weiss addressed the following questions to help guide your decisions.

• What is the short-term response to various nutrient deficiencies?
  
• Are there any long-term impacts to an oversupply of a nutrient?
  
• How accurate or reliable are current National Research Council's recommendations?
  
• Is the nutrient in question a major driver or requirement of milk production?

Weiss provided some statistical analysis to help nutritionists create strategies to reach the right target in each pen or group. Kuhn North America sponsored the webinar. The entire presentation (with questions following the webinar) are archived on our website. They can be viewed here.

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The author is the online media manager and is responsible for the website, webinars and social media. A graduate of Modesto Junior College and Fresno State, she was raised on a California dairy and frequently blogs on youth programs and consumer issues.