Transcript Formalin - University of Vermont

An Investigation of Hairy
Foot Wart Treatments and
Associated Environmental
and Public Health Risks
Nicole Desnoyers
Brent Frankland
Micha Cetner
Josh Hayford
Hairy Foot Wart
or
Papilomatous Digital
Dermatitis
What's the deal?

Caused by bacteria
– Genus Treponema
First reported in the U.S. 25 years ago
 Extremely contagious

– 31% to 89% in 3 years
– 30% of cows sent to U.S. slaughterhouses
- Wells et al. 1997
Associated Cost
20% of all dairy lameness cases
 Milk loss
 Reproductive problems
 Premature culling
 Major implications for Vermont

– $1.2 billion a year
– $70 million in gross wages
Treatment

Topical application of antibiotics
– Not practical on large herds

Medicated Foot baths
– Copper Sulfate
– Formalin
– Alternative Treatments

What about the waste?
Copper Sulfate
-5-10%
concentration foot bath
-Effective for 150-300 cow passes
Hazards to Farm Employees

General Use Pesticide
– No permit required
Toxicity Class 1 – Highly Toxic
 Acute Effects

– Extremely caustic/corrosive – Burns
– Ingestion

Oral LD50 in rats is 472 mg/kg
Hazards to Farm Employees

Chronic Effects
– Liver Disease in vineyard workers
– Anemia
– Damage to Red Blood Cells
– Kidney Disease
What about the waste?

Used foot bath = industrial waste
But….
What about the waste?
What does that amount to?

Average Foot bath
– 62 gallons of water
– 26 lbs copper sulfate = 6.5 lbs copper
Problems?
-Frequency of use
-Amount of land
-Soil type
Soil tests Important!
Surface Waters
Extremely toxic to fish and aquatic
invertebrates
 96 Hour LC50 to pond snails = .39 mg/L
 Behavioral Changes

Is there Significant Risk?
Hazard to employees
 Unregulated disposal is a concern

– Copper loading in soil
– Danger to aquatic species
FORMALIN
1.
2.
3.
4.
5.
6.
7.
8.
9.
37-39% Formaldehyde Solution
Strong, pungent hay/straw-like odour
Formalin - CH2O (Formaldehyde – CH2O3)
Non-Corrosive, Biodegradable
Not regulated by EPA
Used in Footbaths in Dairy Industry – Control PDD
Breaks down rapidly to form formic acid and carbon monoxide
Disposed of in croplands
Human Health Risk
Formaldehyde in Water
Formaldehyde dissolves rapidly in water
Half-Life of 2-20 days in clean fresh water
Decomposed in ~30 hours in lake water (aerobic) and 48 hours (anaerobic)
Formaldehyde in Air
Formaldehyde molecules react with hydroxyl radicals:
1)hydrogen and carbon monoxide stable molecules, or
2) formyl (HCO) radicals and hydrogen atoms
Half-life of 7-71hours, limiting long range distribution
HCO radicals important in smog generation – Urban areas
Formaldehyde and Wildlife
No build up of contaminant residues in plants and animals
Marine algae sensitive to formalin
Fresh water algae slightly more tolerant
Bioaccumulation in fish – no significant results
Initial toxic effects in fish – variable (striped bass most sensitive)
Formalin kills larvae of terrestrial invertebrates and nematodes
No data on mammals, bird and reptiles
Animals in lab – enhanced sensitization to inhaled allergens
Rats – 1)cell proliferation in nasal and respiratory tract → inflammation and
ulceration → increased tumors
2) Gastrointestinal tract → lowered food and liquid intake
Animals exposed to high levels – shortened lifespan, reproductive
problems, lowered fertility, changes in appearance or behaviour
No carcinogenic effects from formalin given orally
Formaldehyde] (mg/m3)
The response of tumor proliferation to increasing concentrations of
formaldehyde in lab rats. (Montecello et al., 1996).
Formaldehyde and Human Health
Formalin cause irritation of eyes, nose, throat, and burning of
skin
Ingested – severe abdominal pain, vomiting and possible
death
People exposure to formaldehyde – cancer of nose and throat
Allergic reactions from household and personal products
Symptoms may only occur long after exposure
Formaldehyde and all bi-products (incl. formalin) possible
carcinogens
Evidence of tumors in upper respiratory tract
No evidence of abortion associated with maternal and
paternal exposure
Known to cause insomnia, lack of concentration, memory loss
or loss of appetite
State Regulation Governing Formaldehyde
Vermont – standards in workplace, mainly in industrial and commercial
settings, disallowed on farms
Agricultural businesses rarely visited, random inspections carried out
periodically
New York – no stringent regulations in agricultural use, but use with caution
and with safety equipment
Standards set for non agricultural workplaces
Alternatives

Improved Hygiene
– Flooring
– Living conditions

Footbaths other than formalin and copper
sulfate
– Contact time with the hoof
– Concentration of the chemical
– Health concerns
Antibiotics
 Kovex Foam

Living Conditions

Keep dairy cows out of locations which harbor
the potential for bacterial growth by promoting
exposure to sun, air flow, and dry conditions
Flooring Types

Reduces the chance
of PDD
– Rubber-slat flooring
system
– Straw yards

Increases the chance
of PDD
– Solid concrete floors
Alternative Footbaths
zinc sulfate
 acidified sodium chlorite
 bleach
 iodine products
 peroxides

Antibiotics

Topical broadspectrum antibiotics
– Tetracycline and
oxytetracycline
Most effective way at
treating PDD
 Issue with antibiotics

Kovex Foam
A new alternative
 Highly accepted for
easy use and
effectiveness over
footbath method
 No seen harmful
effects on cows or
workers

Alternative overview

Combining tactics of
better hygiene along
with better flooring
systems and
environmentally
friendly PDD
treatments without
harming cows or
workers
Recommendations
PDD infections - large financial impact on dairy industry
Loss of approx. $190 million ± $130 million
Farmers main concern - Financial feasibility, practicality, and most
rapid recovery results
Only half cows affected show signs of lameness
GENERAL CARE:Wetter yearly climate - very important
Well ventilated Barns
Housing Facility – Clean and Dry
Cleaning tools and footbaths after use – hoof-trimmer
Automatic mechanized Alley-Scraper
Prevention:
Neither Formalin nor Copper Sulfate treat PDD lesions, only preventative
Copper sulfate – expensive @ ~$80/ 50lb bag (~$1.60-$2.00/lb) and 1 bag
/footbath/200 cows/weekly – environmental problems
Zinc sulfate – expensive @ ~$42/50lb bag (~$0.84/lb) and 1
bag/footbath/200 cows/weekly - efficient preventative but dissolves poorly –
environmental problems
Formalin – inexpensive @ ~$250/55 gallon barrel (~$4.50/gallon) and
1gallon /footbath/~120 cows/weekly
Vermont - copper sulfate in footbath more common
New York - Formalin more common
Prevent burning of cow feet
Formalin most cost effective whole heard preventive treatment CARCINOGENIC
Caution and correct safety equipment
Treatment:
Clean infected area
Scrape lesion
Antibiotic topical application – oxy-tetracycline powder
Not practical for large herds and expensive
Wrap in conjunction with footbath preventative program
Spraying of feet is affective but not practical – dilution, disturbance,
contamination