Formulating a modern dairy diet

5 Min Read

The dairy industry and the nutritional requirements of dairy cows have changed considerably over the last several decades, driven by diverse factors such as cow genetics, consumer demands and economics. Today’s dairy diet takes all of these factors into account to deliver as much milk as possible for the most economical cost per cow. Many of these diets are supplemented with Rumensin®, which increases milk production efficiency* by delivering more milk per pound of feed.

Modernizing past clinical research

Today’s modern dairy practices require considerably fewer resources than they did in the past. For example, the resources required to produce 1.0 million metric tons of energy-corrected milk in 2017 were considerably reduced relative to those required in 2007, with 2017 production systems using 74.8% of the cattle, 82.7% of the feedstuffs, 79.2% of the land and 69.5% of the water as compared to 2007.1 Over the past century significant strides have been made in understanding cattle metabolism and nutrition such that modern dairy cattle are more feed efficient and are fed more precisely balanced diets than their ancestors.2 In addition, our industry’s understanding of how a cow’s nutrition affects factors such as milkfat has increased greatly over the years.

Because of the differences in cows’ feed and nutrition and changing consumer tastes, Elanco is currently conducting research in order to provide data that give dairy producers and nutritionists the information they need to make the best decisions for their operations and herds. As a result, conducting research that includes a trusted product like Rumensin as a component in today’s dairy diets is critical.

The “modern dairy diet”

Our current research is representative of what nutritionists and dairy producers use in the field now and focuses on using corn silage as the basis of the forage portion of the diet. We are also focusing on fatty acid, metabolizable protein and amino acid supply within the diet using current recommendations. We are focused on what our customers are doing and are using that to guide our research.

Factors used to determine a modern dairy diet

Dairy nutritionists use a computer-based ration-balancing program that has underlying modeling of the cow’s biology associated with it to create a diet for a particular animal or herd. By inputting information, including the cow’s age, gestational period and level of milk production, the nutritionist determines what targets the diet needs to achieve to supply the right nutrient mix for that cow to support the desired levels of milk production, milk components, and weight gain.

There are also minerals required in small amounts that a cow cannot produce on her own, including zinc, manganese, copper, cobalt and iron. These trace minerals, which promote good health and help with reproduction, should also be part of a modern dairy diet. Dairy cows are the high-performance athletes of the animal world, so they need balanced nutrition to be healthy and produce milk and healthy calves.

Keeping the rumen healthy

As the largest portion of the cow’s digestive tract, the rumen is where nutrient metabolism occurs by bacteria and other microbes. These “bugs” need to be kept happy to meet the caloric and protein requirements of today’s dairy cows. A nutritionist will then focus on what is most economically favorable to leverage in terms of sources of protein and energy for the herd.

Satisfying changing consumer tastes

Periodically, what consumers are looking for from dairy products changes. For example, fat production has been favorable in terms of price for the last few years, whereas prior to that protein in milk was more valuable. Changing consumer trends have a big effect on where economic benefits for dairy producers are found and, consequently, play a role in how dairy diets are modified in order to meet specific market demands.

Rumensin increases energy/lb

Rumensin provides value throughout the lactation cycle.

  • In early lactation, Rumensin delivers more energy from every pound of feed, increases dry matter intake (DMI) allowing cows to more rapidly return to a positive energy balance3-5

  • In mid- and late lactation, cows produce more milk per pound of feed5

  • In dry cows, Rumensin promotes more efficient use of feed to maintain body condition6

In addition to optimizing feed potential and maximizing energy, Rumensin prevents and controls coccidiosis — a disease that can cause intestinal damage, long-term productivity issues and even death in calves and heifers if not treated.  

Talk with your nutritionist or Elanco sales representative about a dairy diet that fits today’s herds and how to make Rumensin part of a long-term strategy for improved milk production efficiency.

*Production of marketable solids-corrected milk per unit of feed intake.


The label contains complete use information, including cautions and warnings. Always read, understand and follow the label and use directions.

CAUTION: Consumption by unapproved species or feeding undiluted may be toxic or fatal. Do not feed to veal calves.

Dairy cows

For increased milk production efficiency (production of marketable solids-corrected milk per unit of feed intake)

Total mixed rations (complete feed): Feed continuously to dry and lactating dairy cows a total mixed ration (“complete feed”) containing 11 to 22 g/ton monensin on a 100% dry matter basis.

Component feeding systems (including top dress): Feed continuously to dry and lactating dairy cows a Type C medicated feed containing 11 to 400 g/ton monensin. The Type C medicated feed must be fed in a minimum of 1.0 lb of feed per cow per day to provide 185 to 660 mg/hd/d monensin to lactating cows or 115 to 410 mg/hd/d monensin to dry cows. This provides cows with similar amounts of monensin they would receive by consuming total mixed rations containing 11 to 22 g/ton monensin on a 100% dry matter basis.


1Capper JL, Cady RA. The effects of improved performance in the U.S. dairy cattle industry on environmental impacts between 2007 and 2017. J Anim Sci. 2019;98(1):1-14.

2Eastridge ML. Major advances in applied dairy cattle nutrition. J Dairy Sci. 2006;89(4):1311-23.

3McCarthy MM, Yasui T, Ryan CM, et al. Performance of early-lactation dairy cows as affected by dietary starch and monensin supplementation. J Dairy Sci. 2015;98:3335-50.

4Schroeder GF, Strang BD, Shah MA, et al. Effects of increasing levels of monensin in dairy cows in early lactation. Abstract T279.

5Shah MA, Schroeder G, Strang BD, et al. Effect of monensin concentration on dry matter intake during the transition period of lactating dairy cows. J Dairy Sci. 2008;91(Suppl 2):268-9.

6Symanowski JT, Green HB, Wagner JR, et al. Milk production and efficiency of cows fed monensin. J Dairy Sci. 1999;82(Suppl 1):Abstr.


Rumensin, Elanco and the diagonal bar logo are trademarks of Elanco or its affiliates.

© 2020 Elanco.


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