VTS257: Lg Animal Diseases & Nursing

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