MASTISIS CONTROL PROGRAM ON DAIRIES WITH HIGH
INCIDENCE IN FIRST CALVING HEIFERS
C.N. Acuña and R.E. Chertcoff
Agro-veterinary group of advisers in milk quality and mastitis (GAV) Lincoln . Pcia. de Bs.As.
Argentina
Introduction
This paper evaluates the results of mastitis control in two dairies placed in Buenos Aires
Province, Argentina, with significant incidence of Streptococcus agalactiae and Staphylococcus
aureus infections in first calving heifers.
Materials and Methods
The present research was done from December 2001 to November 2002, in a farm with two
dairies (Dairy I & Dairy 2) where 1400 Argentine Holstein cows are milked, producing a average
of 28 liters/cow/day. On bulk milk tank, somatic cell counts (BMTSCC) were realized as
indicated by FIL/IDF (148A-1995), standard plate count (SPC) as in (FIL/IDF 100B-1991),
counts in pasteurized milk (LPC), counts in milk with previous sample incubation (PIC) and
coliforms counts (CC). The sampling, the isolation of BMT, clinic, sub clinic and post-calving
samples and the antibiograms were realized according the norms indicated by the National
Mastitis Council (NMC)(2).
Results and Discussion
The farm was first visited in December 2001; the pit milking routine then in practice was the
following: teats were washed with water, first skirts were observed, pre-dipping was done with
chlorine (+/-10ppm) by spry system, drying individually each teat with newspaper paper.- Post
dipping was done by immersion with an iodine product at 0.5%, after all cows from one row had
been milked. Table 1 shows the initial values of BTSCC, SPC, CPI and CC for both dairies.
BTSCC
Dairy 1
Dairy 2
Table 1
SPC
CPI
CLP
CC
1x10 3 Cells/ml
1x10 3 CFU/ml
1x10 3 CFU/ml
CFU/ml
CFU/ml
588
259
19
55
25
132
210
310
400
>3.000
For both dairies Staphylococcus aureus & Streptococcus agalactiae were isolated, the level of
environmental pathogens Streptococcus non agalactiae was high >2000 CFU/mL. The
bacteriological analysis of the water used for teat washing gave an elevated contamination with
coliform bacteria and Pseudomonnas spp in Dairy 2.- The results from the clinic cases (n=40)
showed a 78.75% prevalence of S.aureus. The prevalence of coliform bacteria (Klebsiella spp)
in clinical samples was 11.25%.- Previous data over all cows showed the following values of
prevalence: S.aureus: 24.53% ; S.agalactiae: 3.36% ; Corynebacterium spp : 24.14% ; Coliforms:
2.34%. The antibiogram results in samples taken from clinical cases showed a resistance of
S.aureus to pencilins and ampicilins. In January 2002, pit routine was modified, washing with
water was eliminated, first skirts were taken, then a pre dipping with chlorine (200ppm) was
applied and teats were dried. The post dipping was done immediately after cups off. The
lactation treatments were replaced by a intra mammary formulation of amoxillin-clavulanic acid
combined with an intra muscular injection of Gentamicine; the dry cows treatment was done
with a cloxacilin-benzatidic formulation. During February 2002, clinic cases were evaluated,
relating them with “days from calving” and “number of calvings” ; results are shown in Table 2
Table2
Days from calving
< 10
10-100
101-250
250
Number of calving
1
2
3
4
% Clinical Mastitis
20.68 %
6.89 %
51.72 %
20.68 %
43.48 %
26.08 %
10.87 %
18.37 %
A high % of clinical mastitis was observed in first lactation heifers. According this, samples
were taken from first calving heifers between 6 to 10 days after calving, finding a 6.52% of
heifers infected with S.aureus and 10.52 with S.agalactiae. A treatment previous to calving was
then put in practice, for every heifer with calving date > 45 days, with a product for dry cows
containing cloxacilina benzatinica. The results in the heifers was 98% succesfull (n=100).
Animals with chronic mastitis was found in a 29.41, 23.53 and 47,06 % for first, second, third
and more calvings; the % for first and second calvings was considered elevated (52.93%).
Then all the cows where sampled between the 6 and 10 day after calving, so to identify the
chronics and evaluate the dry cow therapy. S.aureus was not found in the 81.46% samples of
587 cows that were analyzed. Actual prevalence of sub clinical with S.aureus and S.agalactiae in
both herds is 12.97 and <1 %, this show a reduction of the sub clinical infections of 47.13 and
70.24% regarding initial data, which was 24.53 and 3.36%.- Actual prevalence of
Corynebacterium spp is 5.05%, which show a reduction of 79.08% from the initial data of
24.14%. It is supposed that this is because of the change of type and way of application of the
post dipping product. Table 3 shows the monthly evolution of the BTSCC in both dairies from
December 2001 to November 2002.
Table 3
BTSCC
Dairy 1
Linear Score
Dairy 2
Linear Score
1x10 3 Cells/ml
December/01
March /02
June /02
July /02
August /02
September/02
October /02
588
343
236
240
220
224
203
1x10 3 Cells/ml
5.5
4.8
4.2
4.3
4.1
4.2
4.0
259
133
182
200
192
266*
145
4.4
3.4
3.9
4.0
4.0
4.4
3.5
November /02
202
4.0
152
3.6
During September BTSCC had gone up in Dairy 2, caused by an increase of clinical cases by
environmental bacteria (coliforms), the motive was that the spray pre-dipping system was not
working; it was then replaced by a chlorinator. The SPC values for the month of October 2002
were 2000 CFU/ml for dairy 1 and 5000 CFU/ml for dairy 2. The high incidence of mastitis in
first calving heifers, that was principally generated by feeding them with non pasteurized milk
when they were calves, actually it has been corrected treating the milk given to calves with
0,15% of 30% peroxide of hydrogen (H2O2) and heating to 50°C. With this treatment, initial
milk bacteria presence is reduced to > a 3 log 10, similar to what is achieved by pasteurization, in
both cases depending on initial level of bacterial presence.- This new practice, which needs to be
evaluated again, is employed instead of pasteurization, as the Argentine actual situation of dairy
economy limits the use of pasteurizing equipment in the dairies. For the same reason, good milk
replacers cannot be bought by dairy farmers.
Conclusions:
The good results achieved in lowering the BTSCC in both dairies was principally obtained
because of the pre calving treatment for the first calving heifers, plus other decisions that were:
1. Dry cow treatment with the correct antibiotic, as S.aureus resistance was found for the
antibiotics that had been previous in use.
2. Treatment of cows in milk
3. Corrections done on the pit milking routine.
All the same, importance must be given to prevention of mastitis in first calving heifers, as
infected animals produce less milk and this situation does not get better even in the cases that the
treatments work well, producing important economical loses.