Mastitis

Question 1

How do we diagnose Environmental Mastitis?

Answer 1

• *High/increasing incidence of clinical mastitis,
• Low***Bulk Tank SCC {BTSCC}

definitive Dx requires detection of environmental mastitis pathogens in milk
{culture, molecular diagnostic tests}

Question 2

What is the most common isolate in Environmental {Streptococcal} Mastitis?

Answer 2

​Streptococcus uberis

then S.dysgalactiae

Question 3

How long does the milking procedure usually last?

Answer 3

5-8 min {depending on the cow}
if good milk ejection & machine function

Question 4

Pre-dipping controls ______ mastitis,
whereas post-dipping aims to control _____ mastitis.

Answer 4

Environmental;
Contagious
bc that cow is going back to the barn & that sphincter is open
- will take bout 30-40 min to close-
teat defenses compromised for 2-3 hours
therefore you want fresh food available & keep them standing

Question 5

The 2 types of mastitis are either {generally, usually}
persistent & subclinical OR transient & clinical. Which is which?

Answer 5

Contagious mastitis:
persistent & subclinical subclinical
greater economic impact on dec.milk production

Environmental mastitis:
transient & clinical
greater economic impact on unsellable/discarded milk

Question 6

What are the major & minor pathogens associated with contagious mastitis?

Answer 6

Major:
Streptococcus agalactae
Staphylococcus aureus
Mycoplasma bovis

Minor:
Corynebacterium bovis

Question 7

What is the method of definitive diagnosis for detection of contagious mastitis?

Answer 7

CULTURE!

Question 8

Streptococcus agalactiae as well as Staphylococcus aureus contagious mastitis pathogens are both capable of beta-hemolysis. How do we differentiate the 2?

Answer 8

Streptococcus agalactae

• catalase {—}
• esculin {—}
• CAMP {+}

Staphylococcus aureus

• ​catalase {+}
• Coagulase {+}

Question 9

What would we use these for & why?

Answer 9

Contagious mastitis
Staphylococcus aureus

this pathogen is often resistant to intramammary antibiotics
& some strains produce ß-lactamase

these antibiotics {pictured} are ß-lactamase susceptible

Question 10

Why does treatment at dry off have a higher success in treating contagious mastitis {S.aureus}?

Answer 10

1. Longer acting antibiotic formulations
2. antibiotics not milked out
3. gland undergoes repair

Question 11

You’re on a farmcall with Dr. Bishop, and he explains that he’s sure contagious mastitis making its way around his herd. Observing {aka distance exam}, you find these cows seem off in other ways. You count 9 with a head tilt, and 12 with nasal discharge. What do you think you’re dealing with & what are you gonna do about it?

Answer 11

Mycoplasma bovis
characteristic presentation: “pneumonia-arthritis syndrome”

use antibiotics approved for Mycoplasma in cattle:

• Resflor {Florfenicol & flunixin meglumine}
  
  • IM dose given to dairy cow →60day w/d
• Nuflor {Florfenicol}
• Draxxin {Tulathromycin}
• Baytril {Enrofloxacin}

ß-lactams won’t be effective d/t lack of cell wall

Question 12

What is the legal limit of bulk tank somatic cell count {BTSCC} per mL, for Grade A milk in the US?

Answer 12

750,000/mL