Project Overview
Commodities
- Animals: bovine
- Animal Products: dairy, meat
Practices
- Animal Production: genetics
- Crop Production: nutrient management
- Education and Training: workshop
Proposal abstract:
Manure application to crop fields is an economical method for dairy farms to recycle essential nutrients excreted by cattle into fertilizer. However, excess nitrogen (N) and phosphorus (P) in agricultural soils contribute to eutrophication of adjacent watersheds, which has damaging effects on aquatic ecosystems and subsequently inhibits the ability to use water bodies for irrigation, drinking, or recreation1. To maintain and enhance water quality and soil health, Vermont farms must abide by Required Agriculture Practices (RAPs); RAPs include implementation of nutrient management plans and restrictions on manure application2.
Nutrient management planning can require large overhead investments for dairy farms. Manure storage infrastructure, specialty cropping equipment, additional land, and supplemental synthetic fertilizers all represent substantial costs for dairy farmers during a time when current and future milk prices are volatile. Despite the expenses associated with RAPs compliance, Vermont dairy farmers reported making changes to management practices and facilities to comply3. In contrast, when similar policies became effective in New Zealand, more farmers reported transitioning to producing other commodities to reduce their impact on water quality3. This demonstrates Vermont dairy farmers' commitment to continuing the state's agricultural legacy of dairy production.
Though Vermont dairy producers have invested in mitigating nutrient runoff, agriculture remains the primary source of P runoff in Lake Champlain 4. As dairy production is Vermont's primary agricultural industry 5, nutrient runoff is primarily attributed to crop fields producing feedstuffs for dairy cattle. Clearly, there is a need for additional tools that can be incorporated into nutrient management planning. Implementation of these strategies must be simple and affordable to allow Vermont dairy farms to continue to thrive.
Solution and Approach
Additional, cost-effective, strategies for nutrient management are required to ensure the economic and environmental sustainability of Vermont dairies. We propose the use of genetic selection to reduce the total concentration of N and P excreted in dairy cattle manure. The proposed research aims to identify phenotyping strategies to enable the development of a national dairy cattle genetic evaluation of N and P efficiency.
For the last century, US dairy farmers have utilized breeding values computed in the national genetic evaluation to improve the next generation of their herds. Breeding values of N and P excretion will enable dairy farmers to reduce the total nutrients excreted in manure over time. The only cost to farmers for implementation would be the same investments currently being used in their breeding programs. Therefore, selection has the potential to be an affordable tool in nutrient management planning for dairy farms.
Project objectives from proposal:
We hypothesize that N and P efficiency breeding values of dairy cattle will contribute to a systems-wide solution to agricultural runoff. The goal of this project is to identify phenotyping strategies to enable genetic selection for reduced N and P excretion in dairy cattle manure.
The following research objectives will be pursued to achieve our project goal:
Objective 1: Identify Holstein cows with divergent nutrient excretion phenotypes.
Objective 2: Validate use of urine and fecal spot samples to estimate nutrient excretion.
Objective 3: Estimate genetic parameters of nutrient efficiency and identify correlated traits.
We expect to identify suitable proxy phenotypes to enable a national dairy genetic evaluation for N and P excretion traits. Northeast dairy farmers will benefit from incorporating nutrient efficiency traits into their selection program as breeding for reduced N and P excretion is a low-cost method of nutrient management.