Formulating dairy cow rations
Formulating rations provides cows with the nutrients they need to stay healthy and optimize production. You can formulate rations by hand or with the help of a computer.
Key tips for formulating rations
- A cow’s dry matter intake should be a minimum of 40 percent forage and no more than 60 percent grain
- Acid neutral detergent fiber should be at least 18 percent and neutral detergent fiber at least 28 percent of ration dry matter.
- Early lactation cows need 17 to 18 percent protein in their ration.
- Added fat shouldn’t go above 7 percent of ration dry matter.
- Include a calcium-phosphorus source in the grain mix at 1 to 2 percent.
Formulating rations allows you to feed your animals efficiently. It provides animals a reasonable amount of food containing all the nutrients they need. You can formulate a ration with the help of a computer or by hand. Computers provide a more complete analysis of nutrient profiles in rations and also includes economics.
Expressing computer ration information
A ration analysis reviews the nutrients all of the feeds add to the ration. It doesn’t balance the ration, and thus doesn’t correct any nutrient deficiencies or excesses. For an accurate analysis, you must know how much of each feed you give including the nutrient content.
A ration balancer program combines feeds to meet the nutrient needs set for a ration. The nutrient content of the feed determines how much you feed to meet your herd’s needs. A balancer program doesn’t consider feed costs or profit.
Least cost formulation includes:
Defining the nutrient needs or constraints for the ration
Finding what feeds need combining to meet or exceed these constraints at the lowest cost per pound of dry matter (DM)
Least cost formulations change as feed costs change. The computer will often give an opportunity or break-even cost for feeds not used in the ration. It’s thought to be a good buy when the price of an unused feed goes below the opportunity price. In this case, reformulate the ration to see how much of that feed you can now use.
A true maximum profit ration program includes:
A least cost function
Milk price information
A maximum profit (income over feed cost) for one of the constraints or specifications to formulate on
In maximum profit, the computer selects feeds and a milk production level to obtain maximum profit. In least cost or balanced rations, the computer only selects feeds to meet the nutrient needs specified for a given level of milk production.
Rules of thumb for formulating lactating cow rations
Know the dry matter intake of your lactating cows. Use table 1 as a guide.
Table 1. Determining dry matter intake
|Body weight (lbs)|
|(lbs/day)*||Dry matter intake (% of body weight **)|
* Fat-corrected milk = (milk lb ×0.4) + (fat lb ×15)
** Intakes may be up to 18 percent less for early lactation cows
Total dry matter intake (DMI) of the ration should consist of:
At least 40 percent forage DM or about 1.5 percent of the cow’s body weight (BW)
No more than 60 percent grain DM or 2 percent of BW
Feed 1 pound of grain per 3 pounds of milk if the cows produce between 10 and 70 pounds of milk daily.
Feed grain at 1 pound per 3.5 pounds of milk if the cows produce over 70 pounds of milk daily.
Acid and neutral detergent fiber content
Acid detergent fiber (ADF) should be at least 18 percent in ration DM. Nineteen to 20 percent is ideal, especially when you’re feeding fat
Neutral detergent fiber (NDF) should be at least 28 percent of the ration DM. Forages should account for 75 percent or more of the total ration NDF (1.2 percent of body weight or 21 percent of ration DM).
Protein and nonprotein nitrogen
Make sure the ration meets the cows’ protein needs (16 to 18 percent in early lactation rations). A low rumen degradable protein source may be good in early lactation rations for high producing cows.
Limit urea to 0.4 pounds per cow daily. Don’t feed more than 0.2 pounds daily to cows in phase 1 and 2.
Total fat should not go above 7 percent of the diet DM. No more than 2 percent added fat should be from any one of these sources: animal, vegetable or rumen inert.
When feeding fat, increase the following in the ration DM.
Calcium to 0.9 to 1 percent
Magnesium to 0.3 percent
ADF to 20 percent or more
Minerals and vitamins
Salt should be included in the grain mix at 1 percent. Another option is feeding salt at the daily rate. Individual cows need 1 ounce for maintenance plus 1 ounce for every 30 pounds of milk.
A calcium-phosphorus mineral source should be included in the grain mix at 1 to 2 percent. Another option is feeding these minerals near a rate of 1 ounce per 10 pounds of milk.
Supplement vitamins (A, D and E) and trace minerals in the ration to meet the cows’ needs.
Reviewed in 2018