FieldDxContagious AgalactiaClinical signs, differential diagnosis, treatment and prevention in goats and sheep.
Overview
A disease of sheep and goats causing mastitis, conjunctivitis and arthritis, more complex in goats where several agents can be involved. Mycoplasma agalactiae is the primary cause in both species; Mycoplasma mycoides subsp. capri, M. capricolum subsp. capricolum and M. putrefaciens also implicated in goats.
Clinical signs
- Mastitis with a hot, swollen, painful udder.
- Sudden fall in milk yield and quality.
- Milk discoloured, granular or thick and yellow with clots.
- Later atrophy and fibrosis of the mammary gland.
- Arthritis, one or both sides, with hot swollen joints.
- Conjunctivitis with corneal opacity, sometimes blindness.
- Abortion.
- Respiratory disease in kids.
Predisposing factors
- Subclinical carrier animals, whether seronegative or seropositive.
- Movement of stock bringing carriers into a clean flock.
- Contact with aerosolised body fluids from infected animals.
- Spread through the milking machine.
Treatment
- Fluoroquinolones such as enrofloxacin or marbofloxacin.
- Macrolides such as tylosin or erythromycin.
- Tetracyclines such as doxycycline or tetracycline.
- Lincosamides such as lincomycin.
- Typically 2-10 mg/kg IM or SC every 24 hours for 3-5 days.
- Intramammary treatment as a single dose for mastitis.
Drugs mentioned: Marbofloxacin Enrofloxacin Erythromycin Tetracycline, Tetracycline Hydrochloride Doxycycline Lincomycin Tylosin
Prevention
1. Monitor flocks by serology, culture or PCR on milk or serum. 2. Cull or isolate infected animals. 3. Test replacement stock by culture or PCR before entry. 4. Improve milking hygiene. 5. Pasteurise milk and colostrum before feeding young stock. 6. Use artificial insemination to avoid venereal spread. 7. Inactivated M.
Source
MSD Veterinary Manual — Contagious Agalactia in Small Ruminants (accessed 2026-07-31)
Condensed and attributed, never reproduced whole. Open the full entry in the app.