|Rotz, Clarence - Al|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2005
Publication Date: 7/28/2005
Citation: Rotz, C.A., Zartman, D.L., Crandall, K.L. 2005. Economic and environmental feasibility of a perennial cow dairy farm. Journal of Dairy Science. 88:3009-3019. Interpretive Summary: Economic and political forces are prompting change in the dairy industry. New concepts are being explored to improve the efficiency and profitability of dairy farms while reducing potential adverse effects on the environment. One possibility is the use of perennial dairy cows. A perennial cow is defined as one that remains at a relatively high milk production level for three or more years without cycling through a dry period and the birth of other calves. Some cows have followed this production cycle, usually due to a failure in rebreeding. They do not fit well on today's dairy farms where cows are rebred on approximately an annual basis to stimulate greater milk production. The potential exists to develop the genetics of this type of cow to create full herds on a perennial lactation management plan. A feasibility study was needed to determine how such a management strategy would affect the profitability and environmental sustainability of typical dairy farms. Many issues must be considered in such a study. Because dairy farms are complex systems with many interacting components, a comprehensive evaluation of the whole farm was needed. A farm simulation model was used to evaluate and compare the performance, environmental impact, and economics of dairy farms using traditional and perennial lactation cycles. A perennial cow production system was found to improve the economic and environmental sustainability of traditional dairy farms if a similar level in annual milk production per cow was maintained. This illustration of the economic and environmental feasibility of dairy farms using perennial lactating herds will promote more research and development of this alternative production concept for practical use on dairy farms.
Technical Abstract: More efficient and economical dairy production systems are needed to improve the sustainability of our dairy industry. A concept that should be explored is the use of perennial cows. Perennial cows are those that maintain a relatively high milk production for up to four years without going through the traditional dry period followed by calving. Farm records demonstrate that a number of cows have produced over 20 kg/d for up to four years. A dairy farm simulation model was used to evaluate the long-term performance, environmental impact, and economics of a conceptual perennial cow production system on a typical dairy farm in Pennsylvania. Compared to a traditional 100-cow dairy farm with replacement heifers produced on the farm, use of 120 perennial cows and purchased replacements reduced supplemental protein feed purchases 11%, increased annual milk sales 18%, reduced manure production 16%, reduced nitrogen (N) losses 10%, and increased annual net return to farm management by $10,000 while maintaining a long-term phosphorus (P) balance for the farm. Compared to a traditional 125-cow dairy farm where replacement heifers were purchased, use of 120 perennial cows with purchased replacements reduced supplemental protein feed purchases 14%, reduced annual milk sales 6%, reduced manure production 8%, reduced N losses 4%, and increased annual net return to farm management by $2900. The economic feasibility of the perennial cow dairy farm was relatively insensitive to a lower cow mortality rate or improved milk quality from perennial cows, moderately sensitive to milk and heifer prices and the useful life of perennial cows, and very sensitive to the milk production maintained by the perennial herd. Thus, a perennial cow production system can improve the economic and environmental sustainability of traditional dairy production systems if a similar level in annual milk production per cow can be maintained.