Vermont Dairy Farm Sustainability Project, Inc.

Vermont Dairy Farm Sustainability Project, Inc.

Summary

The intent of the Vermont Dairy Farm Sustainability Project (VDFSP) is to involve dairy industry stakeholders in demonstrating methods for improving water quality and sustaining the Vermont dairy industry. The project addresses whole-farm nutrient balances and management at the farm level through practical methods supported by farmers and their suppliers. Successful methods must maintain, or improve, farm profitability. Once demonstrated, these methods will be shared with dairy industry producers and professionals.

Preliminary results demonstrate the potential for reducing farm nutrient balances through increased precision in cropping and feeding programs. Data collection is complete on eight dairy farms. Preliminary results on farm nutrient status and nutrient use efficiencies are available.

Objectives/Performance Targets

Original project objectives were to enroll ten farms and demonstrate economically viable opportunity areas for decreasing nitrogen and phosphorus loading and improving nutrient management on each farm. Data collection will be continuous for two years in order to compare baseline nutrient balances to nutrient balances after implementation of a farm developed Nutrient Management Improvement Plan (NMIP). All enrolled farms will develop and implement a NMIP they developed in conjunction with their suppliers. Educational programs based on project findings will be developed for farmers, suppliers and consultants.

Accomplishments/Milestones

Data collection to assess farm level mass balances as well as nutrient supply versus requirement on a per animal group and per field basis for both baseline and post implementation phases is complete. Baseline data was analyzed, reviewed and Nutrient Management Improvement Plans developed in collaboration with farms, suppliers, advisors and extension. Plans were implemented in 2002. Data collection continued in 2002 in order to compare post-plan implementation to baseline nutrient status. In conjunction with NRCS, the Vermont Phosphorus Index was calculated on four farms. Data for both baseline and post-implementation years is being compiled and summarized. Educational materials will be developed after data has been analyzed.

Impacts and Contributions/Outcomes

Preliminary analysis of baseline results describes: 1) Overall efficiency of nutrient use on farms, 2) Efficiency of use of fed nutrients, 3) Potential opportunity areas for improved nutrient use efficiency.

Farms studied encompass a variety of sizes and management techniques. Included are seven dairies ranging in size from approximately 70 to 300 milking head and one custom heifer contractor. Strategies employed by farms for raising heifers include all heifers raised on the farm, all heifers contracted, and a portion of heifers contracted. Two of the farms pastured lactating cattle, two fed no corn silage, and one farm imported no fertilizer.

Overall nutrient-use efficiency is described at the whole-farm level based on data collected over the baseline year. The calculation is nitrogen or phosphorus leaving the farm as product divided by nitrogen or phosphorus imported onto the farm, multiplied by 100. Exports include livestock, manure, forages, and milk. Imports include livestock, bedding, nitrogen fixation, fertilizer, and purchased feed. The mean Overall Nitrogen Conversion Efficiency for all farms was 31.6%, ranging from 14.0 to 49.2%. The mean Overall Phosphorus Conversion Efficiency for all farms was 39.4%, ranging from 20.5 to 75.6%.

The Feed Nutrient Conversion Efficiency was calculated as retained nitrogen or phosphorus divided by intake nitrogen or phosphorus, multiplied by 100. Retained nutrients are those nutrients converted to milk or tissue (pregnancy and growth). Lactating groups were modeled using the Cornell Net Carbohydrate and Protein System (CNCPS) on a biweekly basis. CNCPS inputs were based on feed supplier ration ingredient lists and analyses, forage samples, farm measured intakes, bulk tank weights, and, in most cases, DHIA records. Nutrients retained as tissue were calculated by the CNCPS. A weighted average of data points was compiled to describe the Feed Nutrient Conversion Efficiency for each herd. A weighted average was used to account for multiple groups of lactating cows with varying group numbers within farms. The straight mean* Feed Nitrogen Conversion Efficiency for Lactating Cattle across all farms was 26.7%, ranging from 23.3 to 29.6%. The straight mean Feed Phosphorus Conversion Efficiency for Lactating cattle across all farms was 31.6%, ranging from 28.4 to 34.9%.

The Net Feed Nutrient Import for lactating groups was also summarized from CNCPS data points. Net Feed Nutrient Import is calculated as intake of purchased concentrate nitrogen or phosphorus minus milk produced nitrogen or phosphorus. Each farm’s weighted average of data points was compiled to describe Net Feed Nutrient Import for lactating cattle on each farm. Again, a weighted average was used to account for multiple groups with varying group numbers within farms. The straight mean Net Feed Nitrogen Import across farms was 197 g/head/day, ranging from 101 to 276 g/head/day. The straight mean Net Feed Phosphorus Import for all farms was 30 g/head/day, ranging from 10 to 45 g/head/day.

An overall average of P2O5 application versus university-based requirement recommendations was also calculated for each farm. Each farm’s average was weighted by acreage across fields and crop types. The straight mean Applied Minus Recommended Requirement of P2O5 across all farms using commercial fertilizer was 47.8lbs P2O5/ acre, ranging from –8.4 to 130.9. The potential for reduced fertilizer application of P2O5 has been documented. One farm reduced total P2O5 application by 8.3 ton per year. The resulting cost savings was approximately $4,200 per year.

* The use of “straight mean” refers to an equal weighting across farms. The straight mean across farms is not weighted by the number of animals on each farm.

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