infectious, traumatic, toxic (environment or chemical irritant)
Why is beef cow mastitis less of a problem?
being on pasture has a diluting effect
Causes of beef cow mastitis. (3)
confinement housing, calf may be source of infection, S. aureus, Mycoplasma, and environmental pathogens
3 ways to categorize mastitis.
clinical vs subclinical, acute vs chronic, toxic vs non-toxic
Describe clinical mastitis.
visible changes in the milk
Describe sub-clinical mastitis.
mastitis is present (inflammation of the udder), but there are NO visible changes in the milk
What are some reasons we miss clinical mastitis cases on the farm? (6)
don't want cows in the hospital, takes longer to milk, owner gets mad, may not be forestripping cows, culling may mask problems, no incentive to report cases
Which is more common: clinical or subclinical mastitis?
How does DHIA define subclinical mastitis?
>4.0 linear score for the FIRST time in that lactation, based on a composite sample (composite samples are misleading- just because her composite SCC <150k, does not mean one of her quarters isn't over 200K- dilution effect)
How do we define subclinical mastitis?
any quarter with SCC>200k and the milk looks normal
What's a somatic cell?
What are the units of SCC?
cells/mL of milk
Describe acute vs chronic infection.
acute is a new/recent infection; chronic are persistent infections
What causes toxic mastitis?
coliform infections resulting in endotoxemia
What causes non-toxic mastitis?
often subclinical or contagious pathogens
What are the natural external defenses of the udder? (3)
Contagious pathogen that causes chronic infection and abscesses within the mammary gland; generally considered untreatable.
If you do decide to treat Staph aureus, how can you attack it?
extended intra-mammary antimicrobial therapy
How do you definitively diagnose Strep ag?
What is the hallmark of Strep ag infection?
How do you treat Strep ag?
easy fix with antimicrobials and good parlor practices
_________ behaves as an environmental and as a contagious pathogen.
How do you treat Strep uberis?
difficult to treat, often becomes chronic
Mycoplasma results from high risk practices, such as... (4)
home remedies, purchased at sale barn, poor parlor practices, history of respiratory pneumonia
Common clinical signs of Mycoplasma mastitis? (3)
udder still looks full after milking, milk may look normal, recurring bouts of mastitis
How do you treat Mycoplasma mastitis?
you don't.... CULL HER
Control measures for contagious mastitis? (7)
test and cull/isolate, post-dip, back flush b/w each cow, milking hygiene, proper treatment procedures, milk these cows last, pasteurization (before fed to calves)
What are the 3 compartments of mastitis, and the treatments aimed at each?
Tissue/parenchyma- intra-mammary and systemic, long-term
Cow- systemic treatment, supportive care
What pathogens are usually in each compartment of mastitis?
Milk- Strep ag, other Strep, Coag-neg Staph
Tissue/parenchyma- Staph aureus, Strep uberis
Direct methods of determining the individual cow SCC. (3)
direct microscopic cell counts, DHI (electronic cell counts), linear score
Indirect method of determining individual cow SCC. (1)
CMT (california mastitis test)
CMT is a test that is only used for __________; it should be done at ____________.
subclinical cows; the beginning of milking
How does electrical conductivity work as a method of identifying subclinical mastitis?
wit mastitis, blood components enter the udder--> ions are elevated in mastitic milk, making it a better conductor of electricity
What is the number 1 reason you won't culture organisms from 30% of clinical mastitis cases?
the farmer already treated her
If you think you are dealing with Mycoplasma, you should not ____________ the milk.
Define chronic mastitis.
2 or more consecutive test dates with SCC score greater than 4 in the current lactation
Define new mastitis case.
cow with SCC score of greater than 4 for the first time in this lactation
Define a normal SCC.
cows with consistent SCC score of less than 4 during the current lactation
Diagnosing mastitis at the herd level. (2 methods)
bulk tank SCC, bulk tank milk culture
What is the best way to measure the prevalence of subclinical mastitis in a herd?
bulk tank SCC
What is the goal for bulk tank SCC?
What is the Grade A legal limit for bulk tank SCC?
Milk quality measures. (4)
bulk tank milk culture, standard plate count (SPC), preliminary incubation count (PI/PIC), coliform count
Test to determine the total number of bacteria in a milk sample that can grow and form countable colony forming units on a standard methods agar plate.
SPC (standard plate count)
To determine ______, a sample of milk is incubated for 18hr at 55 degrees followed by the SPC procedure; based on the theory that the normal microflora of the cow will not grow substantially when incubated at this combination, while other organisms will.
PI (preliminary incubation count)
An estimate of the number of bacteria that can survive laboratory pasteurization.
LPC (laboratory pasteurization count)- not a state/federally required regulatory test
The legal rules that define standards that pertain to production, transportation, and processing of Grade A milk.
pasteurized milk ordinance (PMO)
What areas are covered in the standards for Grade A milk? (5)
milking barn, cow housing area/cow yard, milk house, water supply, methods of sanitation