Research and Reviews: Dairy

Special Circular 169-99

Ohio Dairy Ration Program: Now With Environmental Information

M. L. Eastridge1 and W. P. Weiss
The Ohio State University Department of Animal Sciences

Abstract

A new release (Version 5.2) of the Ohio Dairy Ration Program is now available. The program is designed to provide for evaluation and least-cost formulation of rations for lactating and dry cows and heifers. The program also provides a feed library, allows for formation of feed batches, and summarizes feed costs on an individual animal, animal group, and herd basis. One of the unique new features is the calculation of nitrogen and phosphorus output in milk and manure on an animal group and herd basis. Evaluation of lysine and methionine in diets has been included in the new release. The program assists in developing feeding strategies for meeting nutritional requirements, minimizing feed costs, and monitoring the nitrogen and phosphorus balance on dairy farms.

Overview of Software

The first version of a computer program developed by faculty at The Ohio State University to evaluate rations for dairy cattle was released around 1982. Since that time, several other versions have been released to incorporate up-to-date research on the nutritional needs of dairy cattle and to take advantage of modern computer applications. An entirely new program was released in 1992 (Version 5.0) with menu operations and many new features. The program was revised in 1994 (Version 5.1), and a new release (Version 5.2) has been completed that provides additional features.

The Ohio Dairy Ration Program is designed to provide for evaluation and least-cost formulation of rations for lactating and dry cows and heifers. Additional features of the program include:

• A library of 108 feeds with typical nutritive composition. (Names and composition of feeds can be modified and feeds not in the library can be added.)
• Selection of individual feeds for a batch mix. The batch can be saved as a "feed" for use with more than one animal group. (Quantity for the batch can be selected based on a desired weight or number of animals in a group and number of feedings per day.)
• A summary of amounts and costs for feeds fed to all animal groups to provide total feed costs and income over feed costs per day and feed cost per hundredweight of milk for the dairy herd. (This option also offers a feature to monitor forage inventory.)
• Provision of environmental information by calculation of nitrogen and phosphorus output in milk and manure on a per group and herd basis.
• Customization of reports before printing by adding and deleting text lines and printing of reports to a printer or a disk file.
• Several options for tailoring the screen to a computer system and the operation of the program based on the user’s specific interests.

Although rations are evaluated and formulated on an individual-cow basis, the program was developed with a herd framework–at one time, the user can work with five lactating cows, two dry cows, and three heifer groups. Summaries of amounts fed and feed costs are available on a per group and herd basis. Feed costs per day can be summarized for any animal group, but income over feed costs and feed costs as a percentage of milk income are provided for lactating-cow groups and the entire herd. The batch feature can be used to determine weights and percentages of feeds in total-mixed rations (with easy updating of dry matter for forages) and concentrate or mineral mixtures.

Inputs for animal groups include:

Body weight, lactation number, and performance inputs allow for accurate estimation of nutrient requirements. Days in milk, environmental temperature, and proximity to freshening are primarily used to predict feed intake. The user can alter the recommendations for DM intake, CP, NEL, minimum neutral detergent fiber (NDF), maximum forage NDF, Ca, P, and Mg.

Composition of feeds can be altered, including levels of dry matter, crude protein, lysine, methionine, rumen degradable protein (RDP), soluble protein, acid detergent fiber, NDF, effective NDF, lignin, starch, fat, ash, NE_L, phosphorus, potassium, calcium, magnesium, sulfur, sodium, chloride, manganese, iron, copper, zinc, selenium, and vitamins A, D, and E. Lysine and methionine recommendations and amounts provided by a diet are expressed as a percentage of essential amino acids (EAA) flowing to the small intestine. Lysine, methionine, and EAA flows to the small intestine are calculated based on microbial CP synthesis (Firkins et al., 1998) and rumen undegradable protein (RUP) in feed. Intakes and outputs (milk and manure) of nitrogen and phosphorus are calculated for each animal group and for the herd. The program also calculates body weight change of cows and ration levels of forage, forage NDF, nonfiber carbohydrates (NFC), forage NDF:NFC, NFC:RDP, nitrogen:sulfur, calcium:phosphorus, potassium:calcium plus magnesium, and cation:anion balance.

The Ohio Dairy Ration Program operates with DOS (IBM-compatible) microcomputers. The program is located in county Extension offices and is available for purchase from the Department of Animal Sciences.

Acknowledgments

The authors express sincere thanks to Jim Lemon (Senior Systems Developer, The Ohio State University, Section of Communications and Technology) for serving as the programmer of the software.

References

Firkins, J. L., M. S. Allen, B. S. Oldick, and N. R. St-Pierre. 1998. Modeling ruminal digestibility of carbohydrates and microbial protein flow to the duodenum. J. Dairy Sci. 81:3350-3369.

¹ For more information, contact at: The Ohio State University, 221B Animal Science Building, 2029 Fyffe Road, Columbus, OH 43210; (614) 688-3059, Fax (614) 292-1515; email:eastridge.1@osu.edu