2003 Annual Report for LNC03-237
Nutrient Management Planning for Dairy Farms Practicing Management Intensive Rotational Grazing
Summary
Data needed to estimate dry matter intake and manure production on seven Wisconsin dairy farms has been collected in the summer of 2003. Dry matter intake from pasture varied from 6 lbs/cow/day to over 30 lbs/cow/day with an average of 12 lbs/cow/day. Milk production averaged 52 lbs/cow/day. Manure production estimates based on these values ranged from 73 to 95 lbs/cow/day. This is significantly less than that the values currently used for nutrient management planning for cows in confinement.
Objectives/Performance Targets
Producers using Management Intensive Rotational Grazing (MIRG) will increase their awareness of the need for Nutrient Management Planning (NMP) and will become more knowledgeable of what is required to develop accurate plans.
Other audiences (agencies and private consultants) involved in the process will be more knowledgeable about NMP issues for grazing farms and improve their ability to assist/support the NMP process.
Accuracy of estimates of manure production by grazing dairy cows will be improved to facilitate NMP by MIRG farms.
Nutrient management plans for the participating farms will be developed, implemented, and monitored to demonstrate to the NMP process to other MIRG farms.
Development and demonstration of a nutrient management planning framework which will enable grazing dairy farms in the north central region to meet current and future nutrient management standards.
Development/modification of supporting NMP software and related tools that provide farmers and their support network with a means for accurately planning and documenting nutrient flows throughout the farm in accordance with nutrient management standards.
MIRG farms in the North Central Region will develop and implement nutrient management plans that enhance their environmental stewardship and improve the natural resource base on which they depend.
Accomplishments/Milestones
Data were collected from seven farms in 2003. Data collected includes pasture dry matter availability before a grazing event and after a grazing event. This provided information on dry matter intake. Pasture quality was measured by taking grab samples at each sampling time. Milk production was also measured during the time that animals were in each sampled pasture. Data were collected three to five times each season on each farm. This provided a total of 46 individual measurements in 2003. Manure was sampled five times at each farm to provide average nutrient content. Supplemental feed levels and quality were also recorded. Feed intake levels of P and N and total P and N excreted in milk allowed us to estimate manure production required to excrete the remaining P and N.
In 2003, the average crude protein level of pasture samples was 20%, the average neutral detergent fiber level was 45%, and average relative forage quality value was 187. Pasture dry matter intake averaged 12 lbs/cow/day. Average milk production was 52 lbs/cow/day. Manure nitrogen content was 7.8 lbs/ton and P2O5 averaged 6 lbs/ton. Using these values, average manure production was estimated to be 93 lbs/cow/day based on nitrogen excretion and 75 lbs/cow/day based on P2O5 excretion. Both of these values are well below the 148 lbs/cow/day currently used to estimate manure production of 1400-lb cows.
Impacts and Contributions/Outcomes
Information generated form this project was incorporated into two grazing schools held in Wisconsin in 2003. The project is providing participating producers information regarding dry matter intake of their cows on pasture. It also is providing pasture utilization percentages, milk production figures, and pasture quality values. These types of values have not previously been available and are being shared with others as representative of typical grazing dairy farms. At the conclusion of the project, this information will represent a unique and valuable database for grazers in the north central region.
The ultimate goal of this project is the development of meaningful nutrient management methodology for grazing dairies. The manure generation estimates are fairly consistent, but two additional years of data collection will provide information to solidify the values that we already have.