Small Ruminant Mammary Disease

Question 1

How long do sheep/goats lactate

Answer 1

• Goats - 305 w/ a 60 day dry period
• Sheep - 180-290 days
  
  • typically allowed to raise lambs for the 1-2 months

Question 2

How do goats/sheep secrete milk?

Answer 2

• apocrine secretion
  
  • milk is produced by budding off of the mammary gland
• Affects SCC -

Question 3

What is SSC

Answer 3

• total number of cells in the milk
• Majority - neutrophils or macrophages
  
  • goat = neutrophils
  • sheep - macrophages
• Determines milk grade:
  
  • A 800,000 cells/ml
  • B 1.5 million cells/ml

Question 4

factos that affect SSC

Answer 4

• parity
• DIM
• stress
• estrus onset
• infection

Question 5

How is SCC measured in small ruminants

Answer 5

• Manual counting - direct microscopic somatic cell count using pyronin y-methyl green dye (DMSCC and PYMG)
• Automated - Fossomatic (flow cytometry), greater precision

Question 6

What are the non-mastitic mammary gland abnormalities common in small ruminants

Answer 6

• Agalactia
• Udder edema
• Precocious Udder
• Gynecomastia

Question 7

What areas should be the focus of mastitis prevention in small ruminants?

Answer 7

• Udder and milking hygiene
  
  • good udder/teat cleaning prior to and after milking
  • Post-milking teat dip
• Milking process
  
  • avoid mechanical trauma (abnormal pressure in vacuum or over milking)
  • improperly cleaned milking equipment
• Dry-off treatment
  
  • Abruptly discontinue milking
  • Intramammary infusion of antibiotics can be used to treat existing infection and prevent new infections
    
    • non antibiotic options: teat sealants, mastitis vaccination, Vie E and selenium supplementation

Question 8

How is Mastitis diagnosed in small ruminants

Answer 8

• California Mastitis Test (CMT)
  
  • detect subclinical mastitis
  • reagent lyses somatic ceslls causing precipitation of DNA and intracellular protein resulting in gell formation
  • reagent changes color in low pH from blue to yellow
  • Trace and 1+ are insignificant - apocrine secretion!
• Milk culture
  
  • to confirm clinical mastitis, direct therapy and determine possible source
  • sample must be collected sterile

Question 9

What are the types of mastitis in small ruminants? differences?

Answer 9

• Clinical mastitis: Staph aureus
  
  • contagious
  • subclinical to gangrenous
  • micro abscesses w/in mammary gland
  • difficult to culture due to intermittent shedding
  • Milk last or cull
• Subclinical mastitis:
  
  • Staph epidermis and caprae - goats
  • Staph epidermis and simulans - sheep
  • Very high milk SCC
• Coliform mastitis: E coli, Klebsiella
  
  • uncommon
  • pelleted stool decreases contamination
• Gangrenous mastitis - “Blue bag?
  
  • acute, associated with ischemic necrosis of the udder
  • Udder initially warm, but then cools
  • dark discoloration often line of demarcation between healthy and dead tissue
  • Staph aureus most likely
  • Requires surgical removal of affected tissue
• Retroviral Mastitis - “Hard Bag”
  
  • caused by Caprine Arthritis Encephalitis virus (CAE) and Ovine Progressive Pneumonia (OPP_
  • Interstitial mastitis 1st recognized at parturition