intro to mastitis

Question 1

list general causes of mastitis

Answer 1

• bacteria
• viruses
• fungi
• physical (trauma)
• toxins
• neoplasia

Question 2

list clinical signs of mastits

Answer 2

changes to the milk
- (presence of clots/lumps/strings)
- changes in colour (off white, yellow, red)
- changes in consistency
- smell

inflammation of the gland
- swollen
- hot
- hard
- painful
- +/- necrosis of the quarter

systemic illness
- reduced yield
- pyrexia
- anorexia
- recumbency
- tachycardia
- tachypnoea
- collapse
- death

Question 3

what are the grades of mastitis

Answer 3

grade 1:
- changes to the milk only (clots/change of colour/change of consistency)

grade 2:
- changes to the udder (heat/pain/swelling)

grade 3:
- changes to the cow (pyrexia, anorexia, tachycardia, tachypnoea etc)

Question 4

what is clinical vs sub-clinical mastitis

Answer 4

clinical: disease can be identified on the basis of clinical signs
sub-clinical: disease is present but no visual signs/additional diagnostics required to diagnose

Question 5

contagious mastitis is caused by which bacteria

Answer 5

• staphylococcus aureus
• streptococcus agalactiae
• streptococcus dysgalactiae

Question 6

is contagious mastitis severe

Answer 6

usually not - tends to be mild. spreads cow to cow almost exclusively during the milking process

Question 7

compare staphylococcus aureus and streptococcus agalactiae and how they cause contagious mastitis

Answer 7

staph aureus:
- often causes chronic, mild or subclinical mastitis
- associated with high somatic cell counts
- very occasionally cuases gangrenous mastitis

streptococcus agalactiae:
- highly contagious
- an obligate udder pathogen living in the gland and occasionally on the skin
- historically very common, now rare
- associated with high somatic cell count herds

Question 8

how does contagious mastitis spread

Answer 8

milking equipment not cleaned

Question 9

what bacteria cause environmental mastitis

Answer 9

• escherichia coli
• streptococcus uberis
• streptococcus dysgalactiae

Question 10

if a cow has a severe case of acute mastitis is it more likely to be environmental mastitis or contagious mastitis

Answer 10

environmental

Question 11

compare streptococcus uberus and escherichia coli and how they cause environmental mastitis

Answer 11

Question 12

explain the five point plan in controlling contagious mastitis

Answer 12

1. post milking teat disinfection = kill any bacteria transferred onto teat duing milking, immediately after unit removed
2. treat clinical cases promptly = aseptic infusion of intra-mammary antibiotic tubes is the most common tx
3. dry cow therapy for all animals = to cure existing infections and prevent new ones
4. cull chronically infected animals
5. milking machine maintenance

Question 13

how is mastitis controlled

Answer 13

• keep in clean housing (sand beds, clean straw yars, stocking density)
• pre milking teat prep