Rick Kohn Louise Lawrence A program to improve dairy herd nutrition using milk urea nitrogen Department of Agriculture

Overview Background Background Project overview Project overview Experience so far Experience so far

Milk Urea Nitrogen

Nitrogen Metabolism Kohn, et al., MD Nutrition Conference

Implications Milk urea is proportional to blood urea. Milk urea is proportional to blood urea. Milk urea is proportional to amount of excess amino acids and ammonia absorbed. Milk urea is proportional to amount of excess amino acids and ammonia absorbed. High milk urea indicates that more than enough N was absorbed into the body. High milk urea indicates that more than enough N was absorbed into the body. Low milk urea indicates that too little N was absorbed. Low milk urea indicates that too little N was absorbed.

Urine N vs. MUN Jonker, et al., J. Dairy Science

Nutrient Balance in a Cow Intake Milk Waste

Target MUN MUN Target Concentrations for Holstein Cows

Target vs. Observed MUN Jonker, et al., J. Dairy Science

Lab Differences Foss 4000 NIRS is not as repeatable as wet chemistry or Foss Foss 4000 NIRS is not as repeatable as wet chemistry or Foss After Sep. 17, 1998 MUN analyses were reduced about 4 units. After Sep. 17, 1998 MUN analyses were reduced about 4 units.

Target MUN Kohn et al., J. Dairy Science

Check List ✓ Milk Production ✓ Feed intake ✓ Diet Formulation ✓ Feed Analysis ✓ Feed Digestibility ✓ Feeding Management ✓ Feeding Behavior

Typical Results Best

Study on feeding in Chesapeake Bay Watershed Surveyed and sampled 450 farms in region Surveyed and sampled 450 farms in region Used milk analysis and survey results to predict N intake, N in urine, N in feces, and N utilization efficiency. Used milk analysis and survey results to predict N intake, N in urine, N in feces, and N utilization efficiency. Jonker, et al., 2002, J. Dairy Science

Effect of milk per cow on N utilization efficiency Jonker, et al., 2002, J. Dairy Science

Effect of intake N on N utilization efficiency Jonker, et al., 2002, J. Dairy Science

Cost of Overfeeding Protein Jonker, et al., J. Dairy Sci.

Environmental Cost of Overfeeding Protein Jonker, et al., J. Dairy Sci.

Project Goal Institutionalize MUN analysis in Maryland and Virginia (and the country). Institutionalize MUN analysis in Maryland and Virginia (and the country).

Participants University of Maryland University of Maryland –Coordination, Quality Control, Teaching, Trouble Shooting, Evaluation Maryland Department of Agriculture Maryland Department of Agriculture –Coordination Virginia Tech Virginia Tech –Teaching, Trouble Shooting Milk Cooperatives Milk Cooperatives –Information disemination Milk Analysis Laboratories Milk Analysis Laboratories –Analysis

Barriers to Use of MUN Inconvenience of sampling and analysis Inconvenience of sampling and analysis Inconsistent analysis results Inconsistent analysis results Lack of understanding of MUN results Lack of understanding of MUN results Lack of incentive to decrease MUN Lack of incentive to decrease MUN

Methods Upgrade milk processor labs to enable routine, accurate analysis of MUN Upgrade milk processor labs to enable routine, accurate analysis of MUN Quality control of MUN analyses Quality control of MUN analyses Education to nutritionists and farmers Education to nutritionists and farmers Provide one-time incentive payments to farmers maintaining low MUN Provide one-time incentive payments to farmers maintaining low MUN

Incentives Nominal payment ($ ) for MUN below target (11 mg/dl) for 3 months Nominal payment ($ ) for MUN below target (11 mg/dl) for 3 months Publication (with permission) of the names of the 10 top producers per county for high milk yield with low MUN. Publication (with permission) of the names of the 10 top producers per county for high milk yield with low MUN.

Experience So Far Presentations and Interviews Presentations and Interviews –Agents, Farmers, Nutritionists, MASCD Contracts with co-ops and labs Contracts with co-ops and labs Laboratory upgrades Laboratory upgrades