Bovine Mastitis

Question 1

Average cost of clinical mastitis case

Answer 1

$250-411 per case
↓ milk production
Discarded and loss of milk quality
↑ replacement cows and labor
Death and culling cost

Question 2

Where does clinical mastitis come from?

Answer 2

Bacteria that has successfully entered the udder

Question 3

Gram + mastitis bacteria

Answer 3

Contagious: Stept. agalactiae and Staph aureus
Environmental: Staph. spp. (CNS) and Strept. spp

Question 4

Gram - mastitis bacteria

Answer 4

Coliforms/ environmental: E. coli, Klebs, Citrobacter, Enterobacter
Others (less common): Serratia, pseudomonas

Question 5

Clinical mastitis

Answer 5

3 grades: Mild (1), moderate (2), severe (3)
Only way to know cause is to cx

Question 6

Field tx protocols (intramammary/ IMM)

Answer 6

Goals is to help reduce #of bacteria
Begins immediately after visual detection of abnormal milk
Tx for 5d (until milk norm)

Question 7

Inflammation

Answer 7

Resolution takes time
No need to tx with mastitis tube
Return to norm in 4-6d

Question 8

Early mastitis tx

Answer 8

Forestripping
Subclinical mastitis

Question 9

Cow factors (consider for tx)

Answer 9

Lactation #
Hind v. front quarter
Immunity (genetics, nutrition, stress, vx)
Anatomy (udder conformation and teat end condition, internal fibrosis)

Question 10

Pathogen factors (consider for tx)

Answer 10

Pathogens differ: invasiveness, response to abx, host immune response
Some won’t respond: yeast, proteus, serratia, pasterurella

Question 11

Tx factors

Answer 11

Choice of abx, route of admin, duration of tx, cost and milk or meat residue period

Question 12

Where to target abx therapy in mastitis due to diff pathogens

Answer 12

Str. agalactiae and CNS: milk/ ducts
Other str. and S. aureus: milk/ ducts, udder
Coliforms: milk/ducts, cow

Question 13

Considerations for duration of therapy

Answer 13

Invasiveness of pathogens
Antimicrobial choice
Risks
Economic cost v. benefit

Question 14

Bacterial cure may be achieved in _______

Answer 14

1-2d

Question 15

Short duration therapy

Answer 15

3d or less
Cows spend less time in hospital pen, producer saves time, milk and money, fewer IMM abx used

Question 16

Clinical mastitis tx options

Answer 16

Tx only severe mastitis
Cx milk for tx decision after 24 hr
Start tx and change after 24 hr

Question 17

Limitations of on farm cx (OFC)

Answer 17

80% accurate for G+, G- and no-growth
Doesn’t ID 100% mastitis pathogens to species level:

Question 18

MN EAst Cx Bi-Plate interpretation: Growth on factor

Answer 18

G+ (Stept. Staph, bacillus, T. pyogenes)
Hemolysis: S. aureus

Question 19

MN EAst Cx Bi-Plate interpretation: Growth on MacConkey

Answer 19

G- (E. coli, Klebs, proteus, pseudomona, serratia)

Question 20

MN EAst Cx Tri-Plate interpretation: Growth on MTKT and Factor

Answer 20

Strep species
Hemolysis: Strept. ag

Question 21

MN EAst Cx Tri-Plate interpretation: Growth on factor

Answer 21

Staph species
Hemolysis: S. aureus

Question 22

MN EAst Cx Tri-Plate interpretation: Growth on MacConkey

Answer 22

G-

Question 23

1/3 no growth

Answer 23

Cow self-cured
IMM therapy contributes to perceived tx success

Question 24

1/3 G-

Answer 24

Most cases self cure
Tx adds cost and residue risk without added benefit

Question 25

1/3 G+

Answer 25

Most responsive cases to tx
Short duration v extended tx

Question 26

_________ mastitis is our target for tx

Answer 26

G+