Submitted to: American Forage and Grassland Council Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 10, 2002
Publication Date: July 14, 2002
Citation: Soder, K.J., Rotz, C.A. 2002. Economic and environmental impacts of utilizing a total mixed ration in Pennsylvania grazing dairy herds. American Forage and Grassland Council Conference Proceedings. 11:212-216. Interpretive Summary: Economic and environmental concerns are stimulating changes in dairy production. Inflation-adjusted milk prices have remained stable or declined for many years, while the cost of production inputs has continued to increase. As sustainable dairy farms are developed for the future, changes must be made to improve their productivity, profitability, and environmental impact. Low cost pasture-based forage systems are a viable management alternative for dairy producers. Grazing of dairy cows typically reduces input costs, but it also decreases milk production. Supplementation of these grazing cows decreases forage demand while increasing milk production to more acceptable levels. However, the question remains as to what is the most economical and environmentally sustainable type of supplementation for grazing dairy farms. Computer simulation was used to compare farming systems that used different feeding methods. In comparison to confined feeding systems, a grazing dairy farm that fed a total mixed ration of supplemental feeds maintained a similar farm profit. Feeding unblended supplemental feeds on a grazing farm resulted in decreased milk production and profitability. When a total mixed ration was used, environmental impacts were similar between full confinement herds and grazing herds. Feeding a total mixed ration to grazing dairy cows provides a viable feeding strategy for increasing production while maintaining similar environmental impact and farm profitability.
Technical Abstract: Rotational grazing can be an economical way to feed dairy cows in today's age of unstable milk prices and increasing input costs. In order to maintain profitable milk production levels, grazing dairy cows are normally supplemented with concentrate, protein, hay, silage, or some combination of feeds. The introduction of the total mixed ration (TMR) has improved the efficiency of feeding confined dairy cows. The advantage of a TMR system is that feed ingredients are blended together, providing the cow with a nutritionally balanced diet in every bite. Combining this feeding approach with grazing can provide higher and more stable milk production for grazing cows, but the economic and environmental impacts of this strategy have not been evaluated. A systematic whole farm analysis was conducted to evaluate the effects of supplementation strategy in well-managed rotational grazing and confinement systems on the productivity, profitability, and nutrient balance of a representative Pennsylvania dairy farm. Feeding a TMR to a grazing dairy herd resulted in a slight decrease ($21/cow) in annual farm profit when compared to a confinement farm of the same size, primarily due to slightly lower milk production. Nitrogen losses and the phosphorus balance were similar across these farm strategies. Compared to an all grass farm where cows were fed a concentrate supplement, nitrogen volatilization loss on a farm feeding a TMR to a grazing dairy herd was 14 lb/acre less and nitrogen leaching loss was 11 lb/acre greater. Economic risk or year-to-year variation in farm profit for the grazing farms was about half that of the confinement farm. This study illustrates that using a TMR to supplement a grazing dairy herd is a viable option to meet the nutrient demands of cows while maintaining high levels of milk production with acceptable environmental impact.