Dry Matter Intake (DMI) refers to the amount of feed a cow eats each day after removing the water content. In other words, it’s the weight of the feed minus the moisture. DMI is a standard way to measure the nutrition your dairy or beef cattle receive and what they need to stay healthy and productive.
Knowing how much DMI your cows need and the main factors that affect it can help you improve herd performance. This article explains why DMI matters, how forage testing helps, what influences intake, and why high-quality feed is essential for cow health and productivity.
Why DMI Matters for Nutrition and Performance
DMI is the most important factor affecting milk production and weight gain in cattle. When cows consume enough dry matter, they perform better. According to Ohio State University, every 2 pounds of additional DMI can lead to 4–5.5 pounds more milk.
All feeds — whether forage or grain — contain water. To understand the true nutritional value of a diet, that water must be excluded. This allows you to compare feeds accurately and balance rations effectively.
For example, you have two piles of corn silage:
- Pile 1: 100 lbs at 55% moisture contains 45 lbs dry matter.
- Pile 2: 100 lbs at 70% moisture contains 30 lbs dry matter.
Both piles weigh the same and also appear similar at first glance. However, the nutritional difference is huge. The same is seen in a silage vs. hay comparison, with hay having a higher DM content. But dry matter isn’t the only factor to consider. For example, silage has a higher nutritional value than hay despite the lower dry matter.
The optimal DMI for each cow depends on factors such as body weight, stage of gestation or lactation, illnesses, and environmental conditions. If cows eat less than their required DMI, you will lose milk yield and profit. High-producing cows are often limited by how much feed they can physically consume and the energy density of that feed.
The closer you can get each cow to her ideal DMI, the better her production, health, and overall performance will be.
How To Calculate The Dry Matter Intake
When you feed cattle, the feed includes water, so it’s important to convert the as-fed amount (weight of feed with moisture) into dry matter to understand how much actual nutrition your cows are getting.
To do this, use this dry matter calculation formula:
Dry Matter (lb) = As-Fed Amount (lb) × (DM% ÷ 100)
You can get the dry matter percentage (DM%) from your feed supplier or through forage testing. Regular forage testing is essential not only to accurately measure moisture and dry matter content but also to detect nutrient deficiencies and contaminants. Even if your cows are eating the right amount of dry matter, poor nutrient quality can still hurt their productivity.
The table below shows an approximate DMI demand for cattle in various life stages. However, your nutritionist should determine exact values based on your herd and feed specifics.
| Dry Matter Demand as a Percentage of Body Weight | |
|---|---|
| Dry dairy cows | 1.8–2% |
| Low-producing dairy cows | 3.0% or more |
| High-producing dairy cows | 4.0% or more |
| Heifers 3–6 months | 3.0% |
| Heifers 6–12 months | 2.75% |
| Heifers 12–24 months | 2.5% |
| Beef Cattle (above 1 year of age) | 2.25% |
| Beef Cattle (weaned, below 1 year of age) | 2.75% |
Use the following formula to get the adequate DMI weight per day for your cow’s body weight:
Dry Matter Intake (lb/day) = Body Weight (lb) × (DMI % of BW ÷ 100).
Critical Factors Affecting DMI Requirements
Dry Matter Intake (DMI) needs vary based on a cow’s life stage and environment. Understanding these factors helps you adjust feed and keep your herd productive.
- Body Weight: Larger cows eat more and need more energy. DMI is often shown as a percentage of body weight. However, this doesn’t always align with age—young cattle often eat a higher percentage of their body weight than mature cows.
- Stage of Production: High-milk-producing cows have the largest DMI demands in dairy cows. Similarly, beef cows need higher DMI when nursing a calf than when dry or pregnant.
- Forage Quality: Poor-quality forage limits how much feed cows can eat. Feed that’s bulky or high in fiber fills the rumen quickly, making cows feel full before they meet their energy needs.
- Fiber Content: Cattle can consume 1.1% of their body weight in Neutral Detergent Fiber (NDF) before their digestive system limits the DMI, according to Michigan State University.
- Feed Composition and Palatability: Your cattle feed ingredients must be a balanced mix of proteins, fiber, fats, and starch to support rumen health, avoid rumen acidosis, and maintain appetite.
- Temperature: Heat stress can significantly affect DMI and subsequent cow productivity. It’s particularly important to understand the relationship between temperature and humidity, and act quickly when signs of heat stress appear.
- Water: High-producing cows need plenty of water, especially in hot weather. Dehydration quickly lowers DMI, and lactating cows are the most vulnerable.
Custom Feed With The Right Nutrients For Your Herd
Optimize your feed program with precision. Star Blends works with your nutritionist to offer custom feed formulations to meet your herd’s dry matter requirements at every life stage. Working together we can create a balanced feed plan that supports your cows’ health, maximizes DMI, and improves productivity. Contact us today to learn more about how we can help your herd.
