extension outreach response to livestock mortality events associated with algal toxin production in...

Extension Outreach Response to Livestock Mortality Events Associated With Algal Toxin Production in Georgia Farm Ponds

Waste to Worth – Denver, ColoradoApril 2013

Susan B. Wilde, Rebecca Haynie, David Kissel, Leticia Sonon and Uttam Saha

Background

• “blue-green algae”

• can photosynthesize but more similar to bacteria than true algae, existing as prokaryotic cells • reclassified as

cyanobacteria

• fix nitrogen, survive in inhospitable environs

• Nonmotile, can be single, colonial, or multicellular

Background

Eutrophication – the addition of nutrients (i.e. Soil erosion, Nitrogen, Phosphorus, Chemicals, Fertilizers, etc.) to an aquatic system

Additional Nutrients Increased Productivity Algal Blooms (some Toxic!)

Influenced by drought High summer temperatures

Toxin Production

Common genera that produce toxins:• Anabaena• Aphanizomenon• Cylindrospermopsis• Microcystis• Oscillatoria• Planktothrix

Three primary toxins:• Microcystins- liver• Anatoxin-a- nervous system• Cylindrospermopsin- liver, kidneys

Toxicity

Concentration in water (ppb)

Microcystins Anatoxin-a CylindrospermopsinHuman recreation uses 0.8 90 4Subchronic water intake, dog 2.0 100 10Acute water intake, dog 100.0 100 200Subchronic water intake, cattle 0.9 40 5Acute water intake, cattle 50.0 40 60*Office of Environmental Health Hazard Assessment (OEHHA), California EPA 2012

Action Levels for selected scenarios

• Subchronic- Multiple day

• Acute- Single day

• Human drinking water < 1 ppb(World Health

Organization)

Microcystis aeruginosa

Stone Lab, Lake Erie Colonies can be almost macroscopic and form a thick floating scum.

Aphanizomenon flos-aquae

Anabaena

Cylindrospermopsis raciborski

Lyngbya wollei

Case Study

• May 2012

• Report of 4 cattle deaths in Gwinnett County, GA

• Attending veterinarian suggested testing pond because it was “bright green”

Clinical Signs

• Weakness & extreme weight loss

• Confusion, loss of coordination • Flaccid or rigid paralysis• Pale colored mucous

membranes & excessive salivation

• Bloody diarrhea• Sudden collapse and death• Green stains on muzzle

Clinical signs are not diagnostic!

Site conditions

• Agricultural runoff pond • <1 acre

• Annual fertilization • Poultry litter

• Unrestricted access

Gwinnett County, GA

Site Assessment Protocol

May 30, 2012• 4.4 x106 cells/mL• TEST: >5 ppb microcystin• ELISA: >142 ppb microcystin

• Identify and count algal species microscopically

• Toxin assays:• Quick field test strip• ELISA kit

Treatment and Response

May 30, 2012 (4.4 x106 cells/mL) • Conservative: 1 gal Cutrine+

June 19, 2012 (3.7 x106 cells/mL)• Fourth cow death• Maximum: 3 gal Cutrine+

June 25, 2012 (1.2 x106 cells/mL)• Appearance of diatoms and

green algae

July & August• Microcystin >5 ppb• Increase in cell density

Media Blitz

• TV and newspaper coverage

Cattle pond samples from:• Dade• Grady• Gwinnett• Johnson• Monroe• Morgan• Spalding• Tift

Dead cow and algae summer extravaganza!

Assessment Results

Cattle pond samples from:• Dade• Grady• Gwinnett• Johnson• Monroe• Morgan• Spalding• Tift• Stephens

RED = reports of cattle deaths

Ponds Investigated14

Ponds w/ Microcystis11 of 14

Microcystins > 5 ppb7 of 9

Ponds in Drought13 of 14

Drought Conditions

USDA (droughtmonitor.unl.edu)

8/7/2012

• News flash: Animals are not that smart

• Cattle, dogs will consume cyanobacterial crusts/mats

• Affinity for water with cyanobloom

Lopez and Costa 1999

Additional considerations

Management Recommendations

• Algaecide and/or water conditioning products

• Aeration• Implementation of BMP’s• Restrict access• Vegetated buffer

• Change fertilization regime• Limit phosphorous

Management Recommendations

Livestock watering options• Limited • Rely on pond

State/federal agencies strongly discourage watering in creeks

Statewide Screening Initiative

Investigate• Landowners send samples via

UGA Ag testing service• Contract basis (pay/sample)• Provide for each sample • Species list• Toxin analysis• Recommendations

Educate• Participate in short courses

Acknowledgements

Dr. Lee Jones, UGA Veterinary Diagnostic Laboratory

Dr. Gary Burtle, Dr. Lawton Stewart, UGA Cooperative Extension Specialists

Brad Bartleme, Jamie Morgan, Graduate Research Assistants

Dr. Mark Risse, UGA Agriculture and Environmental Science

Questions?