Mastitis 2 Flashcards
linear score is better for…
looking at groups of cows
cut off for SCC where one or more quarters are affected?
200,000
what are the two main ways to diagnose mastitis?
milk culture: gold standard, in a lab, in clinic, or on farm
PCR: highly sensitive, can identify dead bacteria, but difficult to interpret
what are the pros and cons of doing a lab milk culture?
pros: highly triained staff using special equipment, they will find the pathogen no matter what, use specialized media, can isolate the bacteria down to the species level (PCR isoalte or MADLI-TOF)
cons: time and cost
pros and cons of in clinic milk culture?
often only an incubator and simple media plates such as bi plates like agar and mcconkey OR tri or quad plates
it’s faster than sending it to a lab, but the results are less specific
what types of bacteria grow on the following media: blood agar, maconckey
blood agar: gram neg and pos
maconckey: gram neg only
pros and cons of on farm milk culturing?
pros: rapid results so you can make immediate treatment decisions (can reduce your antibiotic use), usually bi or tri plates being used which are cheaper
cons: wont get to the species level and youll have to keep frozen samples in case you want further diagnostics
why is it so important to do culture based mastitis therapy? why not just do no culture at all?
knowing the pathogen reduces the use of IMM antimicrobials for clinical cases by a lot!! (IMM is intramammary)
for non severe clinical mastitis cases, there is no difference in clinical outcome waiting up to 24 hours to get results to decide therapy
how will you treat the following:
- severe mastitis
- moderate mastitis with gram positive growth with a low likelyhood of cure
- moderate mastitis with gram positive growth with a high likelihood of cure
- moderate mastitis with gram neg growth
- moderate mastitis with no growth
- supportive care and antibiotics
- no IMM tx, NSAIDs
- IMM tx and NSAIDs
- NSAIDs only, no antibiotics
-NSAIDs only, no antibiotics
note that IMM means intramammary antibiotics
pros and cons of composite vs quarter sampling of milk
compositie samples: risk of getting a contaminated sample increases, but good if youre wondering if a cow has a contagious mastitis pathogen
quarter samples: most likely to give a result–>we only want bacteria that are present on the INSIDE of the mammary gland
what is the proper way to store milk culture samples
- they are ok at room temp for less than 1 hour
- can be in frig for 2 days
- frozen they are good up to 8 weeks
how does freezing affect the pathogens in a milk sample?
freezing the sample slightly decreases E coli and increases staph aureus and slight decrease in mycoplasma if frozen for more than 1 week
why is the preferred route of admin IMM?
because it’s highly concentrated in the milk and there’s lower consumption of the antibiotic
IMM works well for ____ but doesn’t work well for ____
gram positives, gram negs
how long is treatment with a superficial invader vs an invader of the deeper secretory tissues?
superficial: 2-3 days
deep: 5-8 days
what are the 2 options for antibiotics in lactating dairy cows?
Cefa-Lak (cephapirin sodium)
Spectromast (ceftiofur hydrochloride)
Cefa-Lak is labelled for…
clinical mastitis caused by strep agalactiae and staph aureus
the dose is 200mg once and then repeated in 12 hours and this isn’t good enough for staph aureus which invades deep tissues
Spectromast is labelled for…
clinical mastitis caused by E coli, strep dysgalactiae, and NAS, AND for subclinical mastitis associated with NAS or strep dysgalactiae
uhhh it wont work for E coli cuz IMM doesn’t work on gram negs
why do cefa-lak and spectromast suck
because they have huge label claims that are FAKE NEWS and you’re often forced to go off label because the dose or frequency isn’t good enough…often need a CG FARAD and then milk withholds become a pain
which NSAID should be used for mastitis?
metacam
why do we give intramammary antibiotics to dry cows?
to prevent new intramammary infections and to treat any existing intramammary infections
IMM abs work better in an involuted udder compared to a lactating one!
what is blanket drug cow therapy?
the largest use of prophylactic antimicrobials in the dairy industry and is banned in some countries
selective dry cow therapy can be used on some farms (only treat some of the cows instead of all)
why is the abs dose higher for dry cows?
for longevity and to get MIC to last as long as possible
list some examples of abs that can be used in dry cows
Cefa-dry, Spectramast, Dry-Clox
what are teat sealants and why are they used? proper way to use?
they form a physical barrier in the teat canal. they should be applied whether dry cow abs are being used or not. it seals off the teat and is then hand stripped out at first milking
***MUST BE DONE ASEPTICALLY otherwise youre trapping bacteria in the udder and sealing it in there=fatal
true or false: the E coli vaccine is not considered core for dairy cows
FALSE it IS a core vaccine! use killed vaccines that require boosters (only short period of immunity but works really well)
when should you NOT give E coli vaccines (they are bacterins)
too close to calving, or with another bacterin vaccine
it can cause abortions
what are the two most common mastitis pathogens for beef cows?
staph aureus and corynebacterium bovis
how is beef cow mastitis treated?
usually treat the gram pos infections, IMM therapy works, but can use injectables (safer)
you go see a dairy cow with a big ole’ full thickness laceration to one of her teats. How will you fix this?
suture it closed in 3 layers: submucosa, intermediate layer, then skin, DO NOT include mucosa in the first layer.
use a ring block at base of teat with lidocaine (no epi!! this causes vasoconstriction and can create more problems)
true or false: longitidinal lacerations heal better than horizontal ones
true because of blood supply not being cut off as much
true or false: lacerations at the base dont heal as well as at the apex
FALSE they heal better at the base than at the apex
when would you need to do a teat amputation?
when teat damage is irreversible
how do you amputate a teat?
drain the quarter of all milk, and infuse IMM abs. then perform a ring block at the base of the teat and clamp the base of the teat, cut the skin around proximal 3rd of teat, then tighly appose the submucosa and intermediate layers with a continuous horizontal mattress suture
lactococcus and enterococcus are what kind of mastitis pathogen
environmental, similar to strep uberus
