Mastitis is an inflammatory disease of the mammary gland caused mainly by bacterial infections entering through the teat canal. It can be clinical or subclinical and affects milk production and quality. Diagnosis involves somatic cell counts, California Mastitis Test, and culture of milk samples. Treatment depends on causative organism but includes intramammary antibiotics and supportive therapies. Prevention focuses on proper milking hygiene, teat dipping, dry cow therapy, and culling chronically infected cows. Unaddressed mastitis poses economic losses to dairy operations.

1. Mastitis

2. • Inflammatory disease of the mammary gland
• Cause- bacteria, fungi, yeast, spirochetes,
trauma
• Route of infection- ascending via teat canal

3. Types of Mastitis
• Infectious- caused by microbial organisms
• Non infectious – resulting from physical injury
to the mammary gland

4. Mammary Gland
• Made up of 4 independent glands
• Only interconnected by blood supply
• Milk does not pass from one quarter to the
others

5. Economic impact of mastitis
• Most dairy herds, 24-50% of quarters are
infected
• Decreased milk production
• Milk discarded due to medication, presence
of bacteria, and or white blood cells
• Veterinary/labor/medication expenses

6. Factors affecting development of
mastitis
• Sanitation of milking equipment/cows udder
• Trauma to udder through improper vacuum
pressure
• Anatomic/structural weakness of teat canal
• Pathogenicity of bacteria present

7. Symptoms of mastitis
1. subclinical- increased WBC count in milk
2. Acute
- heat, pain
- Discolored milk
- Clots/flakes of blood present in milk
- +/- systemic illness
3. Chronic
- Fibrosis
- Atrophy of mammary gland

8. Sample collection
• Collect samples just prior to milking
• Thoroughly wash udder and teats and dry with a
paper towel
• Swab the teat with 70% alcohol
• Strip each teat 2-3 times before collecting milk
sample
• Sample each quarter individually, unless
collecting composite herd screening samples
• Keep samples refrigerated until plated and plate
within 2 hours

9. Diagnosis
• Somatic cell count
- WBC degrade quickly in milk
- Smears should be made, fixed, stained with 2
hours of collection
- Electronic cell counters
• Strip cup
• California Mastitis Test
• Inline filters

10. Treatment for Mastitis
• Intramammary transfusion
• Systemic/parenteral treatment
Staphylococcal mastitis
- A herd problem
- Treatment of little value, limited effect of Ab
Streptococcal mastitis
- S. agalactiae
- Intramammary Pen G 100,000 units per quarter
very effective

11. Coliform mastitis
- Spontaneous recovery without treatment
- Frequent milk stripping is important in toxic
individuals
- Oxytocin may enhance stripping
Mycoplasmal mastitis
- Treatment has little benefit and will only delay
slaughter or milk sale

12. Control of Mastitis
National Mastitis Council recommends a 5 step plan
1. Milking machine maintenance
2. Teat dipping
3. Early treatment of clinical cases
4. Dry cow therapy
5. Culling cows with chronic mastitis
* Extra: vaccinate dairy cows against gram negative
mastitis using R mutant bacterin

13. Equine Mastitis
• Can occur at any stage of lactation but most
common a few weeks after weaning
• Symptoms
- Mammary swelling, heat, pain, depression
and inappetance
- Ventral edema
- Occasionally mild lameness

14. Equine mastitis
• Diagnosis
- Streptococcus zooepidemicus is most common
isolate
- Utilize procedures mentioned for sampling
Treatment
- Trimethoprim sulfa 5 mg/kg oral BID
- Combo Pen G 20,000 units IM, gentamicin
2mg/kg IV or IM tid
- Supportive hot packs
- No intrammammary treatments used

15. Small Ruminant Mastitis
• Sheep
- Usually S. aureus
- P. hemolytica
- E. coli
Acute with toxemia is life threatening and possible
gangrene of teat
Lameness is often first sign
Routine udder palpation and culling animals with
damaged udders

16. Dairy Goat Mastitis
• S. aureus is most common
• Subcu Pen 10,000 units/kg BID or ½ dose
bovine udder infusion usually works well

17. Milking and Mastitis
• Natural situations and mastitis- any mammal that
is lactating, milking machines change anatomy
enough to cause infection
• Vacuum
- Milking machines have an intermittent vacuum
- A constant vacuum pressure can damage teat
leading to infection
- Must be constantly monitored so damaged
vacuum system does not put too much pressure
on teat

18. Vacuum and Pulsation
• Massage, turning vacuum on and off
1. Shell on outside of teat of stainless steel
2. Liner/inflation- rubber liner of shell, fits
around teat to form an air tight seal
3. The shell plus the liner is called a teat cup, 4
teat cups together are called a claw

19. Pulsation ratios
• 50/50- 50% milk, 50% rest
• 60/40- 60% milk, 40% rest
• 70/30- 70% milk, 30% rest

20. Equipment
• Bucket milker and dumping station- carries
milk to central storage unit
• Around the barn pipeline- takes milk from
barn into the milking parlor
• CIP, clean in place, cleans milking pipeline
• Parlor- clean room where milk is stored

21. Teat sphincter
• Teat sphincter damage
- If damaged, the sphincter allows bacteria to
enter the teat which leads to mastitis
- This occurs when the system is not working
properly

22. Milking technique
• Improper milking technique
- Vacuum levels too long or too strong damage
teat
- Milking time vs rest time in pulsation ratios is
not correct
- Consistency- cows do best on a consistent
pulsation ratio and pressure
- Individual towels to reduce spread of disease

23. Milking technique con’t
• Pre-dip- an antibacterial solution the teat is
dipped into prior to milking, reduces bacteria
spread in teat cups and claws
• Post dip- after milking, usually a special color
to identify cows that were treated, a very
good practice to prevent mastitis
Teat canal remains open for 90 minutes post
milking

24. Vacuum Fluctuation
• Flooding- a huge pressure causes teat cups to
slam against teats can be prevented by
- Air jets
- Liner size larger than water lines, increased
diameter decreases pressure
• Vacuum leaks prevented by
- Vacuum regulator lets air into system to maintain
constant pressure, if it senses a leak, it shuts
enough to compensate
- Vacuum reserve also prevents fluctuation

25. Contagious mastitis
• Spread during milking
• Generally gram (-) but not always
• Subclinical infections lead to spread of
infection as only diagnosis is through
evaluation of milk
• Strep agalactica and Staph. Aureus
• Mycoplasma

26. Environmental mastitis
• Generall gram ( -) but not always
• Often show clinical signs such as fever and
anorexia

27. Strip plate
• 4 cup paddle used to collect milk sample from
each quarter
• Evaluate for visible color or consistency
change

28. California Mastitis Test
CMT
• Performed by mixing equal parts of CMT
reagent and milk
• Milk samples are on 4 cup plastic paddle
• Reagent reacts with WBC and thickens or gels
in proportion to number of WBC
• Greater reaction, higher score
• Rapid test done by farmer identifies
subclinical and chronic mastitis

29. CMT interpretation
• Negative- mixture remains liquid with no
evidence of precipitate
• Trace- slight precipitate or flakes form, then
disappear
• 1 ( weak +) distinct precipitate
• 2 ( distinct +) mixture thickens immediately
and some gel formation

30. CMT Scores
• Negative 0– 200,000 cells
• Trace – 200,000 -400,000 cells
• 1- 400,000-1,000,000 cells
• 2- 1,200,000- 5,000,000 cells
• 3- >5,000,000 cells

31. Electronic Somatic Cell Count
• Done by machine on bulk tank sample
• More accurate count
• Done by milk processor
• SCC composed of 75% WBC and 25% epithelial
cells
• SCC greater than 250,000 indicates subclinical
mastitis by a major pathogen

32. High SCC
• Rise in whey protein and decrease in casein
resulting in lower cheese yields
• Shorter shelf life
• Adverse milk flavors
• Decreased production

33. Milk quality
• Bulk tank- refrigerated a little above freezing
• Pick up – every other day
• Evaluation of milk quality
- SCC normal 100-200,000, paid more for lower
counts
- Antibiotic residue tests for milk
- Freezing point to rule out water added
- Milk fat, milk protein, milk weight all used for
value of milk

34. Economic loss for mastitis
• $165 per year per cow
• Discarded abnormal milk
• Replacement heifers
• Reduced value of culled cows
• Increased labor costs
• Increased veterinary costs

35. Factors influencing susceptibility to
mastitis
• Type of bacteria- some more virulent
• Physiological status of cow- first three weeks of
dry period and first month after parturition cows
are more susceptible
• Age of cow- increases with age
• Level of milk production
• Inherited features of cow
• Milking machine
• Environment- more common if turned out to
pasture, esp. chilling of udder

36. Mastitis Control
• Proper milking hygiene
- Wash hands thoroughly before milking
- Teats should be cleaned and dried before
milking
- Milk clinically infected cows last

37. • Milking machine
- Properly functioning
- Vacuum regulator cleaned and checked
regularly
- Teat cup assembly, milk pipes etc in good
working condition and cleaned regularly

38. • Dipping teat after milking
- Does not reduce existing infection
- Reduces rate of new infections by up to 50%
with a suitable disinfectant dipped or sprayed
on teat

39. • Dry treatment
- Reduce mastitis by effective use of antibiotic
infused in each quarter at last milking of a
lactation
- Best way to cure chronic and sub-clinical
mastitis

40. • Culling of chronically infected cows
- 6-8% of all cows account for 40-50% of all
clinical mastitis
• Nutrition
- Vit E and selenium have been associated with
an increased rate of new mammary infections