Evaluating a Non-antibiotic Treatment of Mastitis in Organic Dairy Cows

Project Overview

OS24-178
Project Type: On-Farm Research
Funds awarded in 2024: $29,938.00
Projected End Date: 03/31/2026
Grant Recipient: Texas A&M University
Region: Southern
State: Texas
Principal Investigator:
Dr. Sushil Paudyal
Texas A&M University

Commodities

No commodities identified

Practices

No practices identified

Proposal abstract:

The proposed solution is to evaluate the efficacy and
cost-effectiveness of using AHV compounds as an alternative to
antibiotics for treating mastitis in dairy cattle. This will be
accomplished through a controlled field trial at a commercial
USDA certified organic dairy farm, comparing udder health, milk
quality, dairy cow performance, and economics between an AHV
treatment group and non-treated control group.

Approximately 120 lactating Holstein dairy cows will be enrolled
in the study, balanced between the AHV treatment and control
groups. Cows will be selected based on elevated somatic cell
counts (>350,000 cells/mL) indicating subclinical mastitis.
The treatment group will receive the AHV mastitis regimen as
designed by Agri-Dynamics, consisting of an initial dose of AHV
Rapid followed by extended dosing of AHV Extend. The control
group will receive standard herd management without AHV or
antibiotics.

The efficacy of AHV therapy will be evaluated using milk somatic
cell counts, milk bacterial counts and identification, and
clinical mastitis incidence. Milk samples will be collected at
the time of treatment assignment and then 25 days after the start
of treatment. Somatic cell counts will be measured by DHIA
testing. Bacterial counts and identification will be conducted at
the lab using standard culture-based techniques. Clinical
mastitis events (abnormal milk, swelling) will be recorded by
farm staff throughout the study period.

Additional health and productivity outcomes will be analyzed to
further assess AHV impacts, including milk production, rumination
time, and survival/retention in the herd. Historical and ongoing
milk yield, rumination, and electrical conductivity data will be
obtained from the farm management system. Cow retention/survival
will be compared between groups using survival analysis.

To evaluate cost-effectiveness, a partial budget analysis will be
conducted from the farm perspective. Costs of AHV products, labor
for treatment administration, and milk discarded in the CON group
during treatment will be quantified based on farm records and
valued at farm prices. The value of potential benefits such as
reduced clinical mastitis, improved milk quality premiums, and
higher milk production will be estimated based on study results
and farm milk prices.

The expected key project outcomes are:

- Determination of AHV regimen efficacy based on somatic cell
count reduction, bacterial inhibition, and clinical mastitis rate
compared to non-treated cows

- Economic analysis indicating potential or lack of return on
investment for AHV therapy under real-world conditions

- Documentation of impacts on milk production, cow health, and
retention to provide a comprehensive assessment of AHV therapy

- Identification of any practical limitations or areas needing
refinement for on-farm AHV use

- Scientifically-validated evidence to support or reject further
research and adoption of AHV compounds as a non-antibiotic
mastitis treatment

The results will objectively inform dairy producers,
veterinarians, and the animal health industry whether integrating
AHV therapy into organic dairy health protocols could be a viable
strategy to combat mastitis. If proven effective and economical
for on-farm use, AHV adoption would support sustainable
agriculture by improving animal welfare and milk quality without
antibiotics. However, if AHV treatment is found ineffective or
cost-prohibitive, it highlights the critical need for research
into additional alternatives for sustainable mastitis control.
Either outcome will provide valuable evidence to guide practical
solutions for reducing antibiotic use and mastitis impacts in the
dairy industry.

Project objectives from proposal:

This on-farm field trial will use a controlled experiment with
enrolled cows randomly allocated to AHV treatment or control
groups. The sample size of 120 cows is obtained using a sample
size calculations in SAS with an effect difference of 10
percentage point reduction in mastitis incidence rate using 95%
confidence to obtain a power of 80%. Approximately 120 lactating
Holstein dairy cows will be enrolled in the study, balanced
between the AHV treatment and control groups. Cows will be
selected based on elevated somatic cell counts (>350,000
cells/mL) indicating subclinical mastitis. The treatment group
will receive the AHV mastitis regimen as designed by
Agri-Dynamics, consisting of an initial dose of AHV Rapid on day
0 followed by dosing of AHV Extend (on day 7). The control group
will receive standard USDA organic program-approved mastitis
management without AHV or antibiotics which will include milking
out the animals and monitoring the cow for clinical signs. Milk
samples will be collected from both treatment and control groups
on day 0 and day 25 after the enrollment. Udder health, milk
quality, cow performance, and economic outcomes will be compared
between groups using the following methods:

Somatic Cell Counts: Milk samples will be
aseptically collected from each quarter of enrolled cows at
treatment start and 25 days after. Samples will be submitted to
Texas DHIA for analysis of somatic cell count (SCC) using flow
cytometry. The SCC results will be used to evaluate AHV efficacy
in reducing subclinical mastitis as indicated by lowered SCC.

Bacterial Counts and Identification: Additional
sterile quarter milk samples will be cultured by the TVMDL lab
using standard protocols at treatment start and day 25. Bacterial
species present and colony forming units/mL will be quantified to
determine impacts of AHV on mastitis pathogens. PCR will identify
major contagious (Staph aureus) and environmental (Strep species)
pathogens.

Clinical Mastitis: Farm personnel will check
cows 2X daily during the study, recording clinical mastitis
events (abnormal milk, swelling). Clinical mastitis incidence
will be compared between groups to assess effects of AHV
treatment on clinical disease.

Milk Production: Milk yield data will be
extracted from the on-farm management software for the week
before and 4 weeks after treatment start. Daily milk production
will be totaled and averaged by week for comparison between
treatment groups.

Rumination and Conductivity: Historical and
ongoing rumination time and milk electrical conductivity data
will be obtained from the farm management system. Conductivity
indicates mastitis and rumination is associated with cow health.
Trends will be evaluated for AHV effects.

Retention/Survival Analysis: Cows will be
tracked until dry off or culling to compare retention/survival
between groups using Kaplan-Meier survival analysis. This
evaluates potential milk production and cow health impacts.

Economic Analysis: A partial budget analysis
will quantify costs of AHV products, labor, and discarded milk.
Value of benefits such as reduced clinical mastitis and improved
milk quality will be estimated based on results. Return on
investment will be determined. 

Lab bacteriology, PCR, somatic cell counting, and economic
analysis will be conducted at the Texas A&M University
facilities. On-farm data collection and cow enrollment will be
performed by the farm staff with training provided. The
controlled experiment with objective measurement of udder health,
productivity, and economic outcomes will provide rigorous
scientific evidence on the real-world efficacy and feasibility of
AHV therapy. The methods align with the principles of sustainable
agriculture by critically evaluating a potential non-antibiotic
alternative to improve animal welfare and milk quality. Results
will guide responsible practices to reduce reliance on
antibiotics.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.