Antibiotic Usage on the Dairy Farm

Why are Dairy Cows Given Biotics? What organs are often implicated?

• Treat bacterial infection

  • Mastitis inflammation of mammary gland

  • Uterine infections/ diseases

  • Foot / Claw

  • Respiratory Tract

What is Mastitis?

Infection of Mammary gland, most common reason to be treated with antibiotics

• 4 quarters, most dairy cows use all four quarters

2 antimicrobial classes approved my FDA for Mastitis

• Beta-lactams

  • amoxicillin, ceftiofur, etc

• Lincosamide

  • pirlimycin

• 4 quarters with bad milk = 4 antibiotic shots

• Antibiotic needle is intramammary and goes inside teat

Do you treat E.coli mastitis with antibiotics?

No, they don’t recover any faster than cows treated without it.

Mastitis symptoms

• Abnormal milk

  • bloody

  • greenish tint

  • clots (cottage cheese looking)

• swollen, redness

• Pus

What causes mastitis, what microorganisms?

• No growth

  • majority of cases that get tested has no growth since cow’s immune system has already cleared it

  • this means you don’t have to use antibiotics to treat this most of the time

  • good to decrease antimicrobial usage for financial reasons

• E. coli

• Env. Strep

What do we do with abnormal milk?

Milk is shunted and does not go into bulk tank so consumer to no consume it

• poured down the drain

• if milk is not too foul and cattle are on treatment they can give it to calves

Metritis

• infection of the uterus

• 2nd most common reason to use antibiotics in a dairy cow

• estimates show around 1/3 diary cattle are diagnosed with this

When do we want cows to get pregnant during lactation?

Around 75 days after giving birth when she is in heat

• uterus should look normal

• she should be making a lot of milk

• she’s making a lot of milk even while she’s pregnant

• dried off and for two months she is not milked and then gives birth

• If she is bred at that 75 day mark, you can capitalize on the amount of milk compared to not being bred

What percent of meat we eat is dairy animals?

20%

Side effects of calving in

• Retained placenta

  • wet moist tissue hanging out of uterus/ vagina

  • is like a wick for bacteria

  • is due to immune repression

  • can turn into metritis

• Metritis

  • foul smelling darker discharge

  • pain full

  • few weeks after birth

  • needs medical attention immediately

• Purulent vaginal discharge

• cytological endometritis

Metritis therapy

• supporting cows immune system with

  • therapy

  • oral supplements

• Nothing should be put in uterus unlike historically

Digital Dermatitis

• “Hairy Heel Wart”

  • fimbriae of wart tissue that looks like hair

  • red ulcerated lesion

  • extremely painful

  • very highly infectious to other cows

What causes DD?

• Abrasion/ break in the skin

• wet environment

• low oxygen environment

• a mix of bacterial presence (not from one bacteria)

DD risk factors?

• dirty muddy pens

• foot trauma

• micronutrients deficiencies

• introduction of new animals

DD treatment

1. Clean/ scrub the lesion with proper restraint

2. Topical antibiotic spray/ powder treatment

   • oxytetracycline

3. wrap / bandage 1-3 days

4. will need reapplications and have footbathing

   • Formalin or copper sulfate in bath

   • cow walks through it

How often are hooves looked at on dairy farms?

2-3 times a year

• cow laying on side

• foot picked up by hydraulics

Foot Rot

• use of Cephalosporin antibiotic

• no milk or meat withhold

• stinky, painful but treatable

Pneumonia

Less common in adult cattle

• increased temp

• tachypnea - increased respiratory rate

• dyspnea - labored breathed

• abnormal posture - extended neck

• abnormal nasal discharge

• cough

• abnormal lung sounds on auscultation

• common in confinement raised calves

Antibiotics

• ampicillin

• ceftiofur

• penicillin

• oxytetracycline

• more available in younger then 20 months since they are not lactating

GI tract

• no approved antibiotics to treat diarrhea and other GI diseases of dairy cattle

• most cases of diarrhea are dietary or viral in origin

Farm treatment records

Treatment record must contain

• treatment date

• animal identification

• dosage

• route of administration

• withdrawal time for milk and meat

• individual who administered the drug

• drug used

• duration of therapy

On-label vs Extra Label

• Must follow label exactly

• any deviation must be covered by a vet label for Extra Label Use (ELU) which includes withhold time for meat and milk

Approved drugs in non lactating vs lactating

Non lactating has a much larger list then lactating cows

FARAD

• to prevent or mitigate illegal resides of drugs, pesticides and other chemicals

Medicated Feed

• Veterinary Feed Directive

• you cannot be adding antibiotics to feed to prevent anything