Feed Testing and Ration Design

Feed Testing and Ration Design

Livestock's nutrient requirements vary with age, size and level of production and reproduction. Nutrient use is most efficient when the nutrient supply in the diet is in balance with the nutrient requirements of the animals.

The nutrient content of feedstuffs varies greatly from field to field, year to year, and species to spe­cies. The level and type of fertilization, stage of maturity and method of storage and processing also affect the nutrient composition of feeds.

To balance rations, one must know exactly what nutrients are present and in what amounts. This information is imperative when roughage mixtures of unknown proportions are harvested, and unfamiliar materials are going to be used in feeding livestock. The only way to get precise information is laboratory analysis of the feed.

A full range of feed-testing services is available at various feed testing laboratories. Feeds can be analyzed for:

• Crude protein;
• Estimated digestible energy;
• Essential minerals and vitamins; or
• Toxic substances such as nitrates and prussic acid.

In order to have valuable feed analyses and advice on feed use, it is essential that samples be properly taken and submitted with detailed information on how feed will be used.

Examples of Rations for Beef Cows

The following are sample rations using straw as the main feed ingredient.

Late Spring/Early Summer Conditions

• 1,300 lb. cow
• air temperature +20º C
• third month of lactation
• calf at side

All amounts are per cow per day on an "as fed" basis using average feed values.

Rations

* The vitamin A-D-E pre-mix contains 10,000,000 I.U.s of vitamin A per kg

Salt should always be available on a "free-choice" basis. Consumption should average one to two oz. per cow per day. As an option, loose salt could be added to the grain mix.

If feeding more than eight or nine lb. of total concentrate per cow per day, it is advisable to divide the concentrate and feed equal portions twice per day.

These rations should maintain the cow's body condition. Requirements will change over time.

Late Summer/Early Fall Conditions

• 1,300 lb. cow
• air temperature +15º C
• four months pregnant
• current year calf has been weaned

All amounts are per cow per day on an "as fed" basis.

Rations

* The vitamin A-D-E pre-mix contains 10,000,000 I.U.s of vitamin A per kg

• Salt should always be available on a "free-choice" basis. Consumption should average one to two oz. per cow per day. As an option, loose salt could be added to the grain mix.
• If feeding more than eight or nine lb. of total concentrate per cow per day, it is advisable to divide the concentrate and feed equal portions twice per day.
• These rations should maintain the cow's body condition. Requirements will change over time.

Mid-Winter Conditions

• 1,300 lb. cow
• no wind, -20º C
• seven months pregnant
• to start calving March 15
• expected calf birth weight 90 lb.

All amounts are per cow per day on an "as fed" basis.

Rations

* The vitamin A-D-E pre-mix contains 10,000,000 I.U.s of vitamin A per kg

Salt should always be available on a "free-choice" basis. Consumption should average one to two oz. per cow per day. As an option, loose salt could be added to the grain mix.

If feeding more than eight or nine lb. of total concentrate per cow per day, it is advisable to divide the concentrate and feed equal portions twice per day.

These rations should maintain the cow's body condition. Requirements will change over time.