Lecture 10: Mastitis & Udder Health Management Flashcards
What are some mastitis 101 info?
-most costly disease and most common for antimicrobials and antibiotics
-130+ different organisms (bacteria, protozoa, algae) but almost always a mix
-Two mostly independent forms
*clinical and subclinical
*Contagious and environmental
What is mastitis?
-inflammation of the mammary gland
-Practically associated with bacterial infection
-Typically 1in5 cows have at last 1 clinical mastitis per lactation
-Ofter the most economically important disease on a dairy farm ($5k-$12k per cows/year)
-The #1 reason for use of antibiotics in dairy cows
When is mastitis more common and how come it it so common?
-Mastitis causing organisms are common on the cow and her environment which is why hygiene is so important
-Bacteria have the potential to enter the mammary gland during and after milking if proper precautions are not taken
-Blood-milk barrier limits the immune system components available to respond to challenge
-Milk is a difficult place for immune cells and antibiotics to function
-Evidence that some cows are genetically programmed for a “better” immune response
What are the different kinds of clinical mastitis?
Visibly abnormal milk
-Mild: flakes, clots, or watery milk; normal quarter
-Moderate: abnormal milk + swollen or hard quarter
-Sever=abnormal milk; quarter and systemically ill cow
What is clinical mastitis and how does it affect the cow/producer?
-Severity is not well correlated with the etiologic agent
-Typically 3-10d of production lost (non-saleable) per clinical case
-Costs include: milk discarded, treatment costs, labour; risk of drug residues; possible risk of infection to other cows
-Typically a substantial majority of cases occur in the first month after calving
-With optimal management the goal is <2% clinical case rate per month
What is subclinical mastitis?
-Inflammation without visibly abnormal milk
-Detected by somatic cell count (SCC) (every month or 3w take samples of every lactating dairy cow elevation in SCC how its detected)
-Somatic cells=immune cells (neutrophils) in milk
-Routinely measured
* weekly (every pick up in ON) in bulk milk all herds
* monthly on individual cows in herd on DHI
What is somatic cell count (SCC)? and why is it important?
-SCC is associated with the probability of bacterial infection (high SCC = Higher risk of infection)
-Linear score (LS) in the log (SCC)
ie linear relationship with milk loss and reduced skewing of group average SCC
-SCC 200,00 cells/ml = LS 4= typical cut point for assumed infection
-Regulatory limit in bulk tank milk = SCC < 400,000 (if more fines and eventual shut off)
What are some control measures for mastitis?
General (not pathogen dependant)
-Milking hygiene and technique (clean dry teats, good milk let down we want to stimulate udder and rapid milk out)
-Clean environment
-Cow comfort (lying down for 12h a day so want to make sure comfortable)
-Dry cow therapy (teat sealant in dry cows)
Pathogen Specific
-Antibiotics treatment protocols for clinical cases
-Vaccination (help reduce clinical severity)
-Selective culling (responsible for infection)
What are some tools that can be implemented that have been proven to prevent mastitis?
-Iodine dip kills bacteria wipe, milk and then dip again
-Clean dry towels every time milked
-Gloves at milking will < transmission
-Teat sealant helps prevent bacteria from going up
What is the NMC 10-step mastitis control program?
- Establish udder heath goals for the herd (SMART)
- Maintain a clean and comfortable environment (cows and ppl)
- Always use proper milking procedures (previous slide)
- Properly use and maintain milking equipment
- Keep good records
- Manage clinical mastitis appropriately during lactation
- Use effective dry cow mamngammnt- all quarters of all cow (teat sealant, treat selectively that have high SCC)
- Use biosecurity protocols (buyer beware) & cull chronically infected cows
- Monitor herd’s udder health status regularly (6w tests milk to check for SCC plus regular check when milk is picked up)
- Periodically review the mastitis control program
How is the diagnosis made for mastitis?
-First see symptoms take sample
-Etiologic diagnosis may be important for treatment decisions, prognosis, and specific preventive measures
-Definitive diagnosis based on bacteriologic culture (takes at least 12-24h or up to 3-4 if taken to animal health lab across campus more so for herd test)
-Some farms can take cultures and plate themselves and find out in 24h very simple
TRUE OR FALSE: you can monitor SCC monthly by using DHI which can help identify certain cows with high SCC and also average to help mange the cows want to cull/keep.
TRUE
What is the California mastitis test?
-A simple cow-side qualitative SCC that can be done on farm
-Detergent in solution reacts with DNA in neutrophils to form gel reaction
-Cheap, fast, and provides info at the quarter level
-If a lot of gel probably infected SCC over 600
TRUE OR FALSE: incidence of new infections only occurs mostly during lactation.
FALSE
it happens mostly during early lactation BUT ALSO the dry period which is why teat sealant is crucial
What are the 2 different types of dry cow therapy?
- Antibiotic
-Long-acting formulations (2weeks)
-Objectives to eliminated existing infections and prevent new IMI during involution - Teat sealant
-Inert physical barrier in the teat end similar to slay
-Objective: prevent new IMI (intra-mammary infection) throughout the dry period
