T E C H N I C A L NOTES Incidence of Clinical Mastitis in a Herd of Holstein Cattle 1 T. R. B A T R A 2, B. J. N O N N E C H K E 3, F. H. S. NEWBOULD 3, and R. R. HACKER Department of Animal and Poultry Science University of Guelph Guelph, Ontario, Canada ABSTRACT
INTRODUCTION
Incidence of clinical mastitis in 760 lactations of 331 Holstein cows was studied for effects of sire, parity, and m o n t h of calving. Incidence of clinical mastitis was higher in hind quarters than fore quarters. Positive correlations between n u m b e r of cases in one quarter with n u m b e r in o t h e r quarters and bet w e e n p r o p o r t i o n infected in one quarter and p r o p o r t i o n infected in others indicated that occurrence of mastitis in one quarter was associated with above average frequencies o f mastitis in the o t h e r quarters of the same cow. Clinical mastitis increased with increase in lactation number up to f o u r t h lactation. Cows calving in January and February more f r e q u e n t l y had mastitis than those calving in March and April.
Mastitis reduces milk yield, changes milk composition, shortens productive life o f affected cows, and is costly to dairy farmers. Rendel and Sundberg (5) suggested that f r o n t quarters arc m o r e p r o t e c t e d and less likely to be injured and to contract mastitis. They also r e p o r t e d an incidence of 14.9% in first lactation c o m p a r e d to 37.7% in f o u r t h lactation. Braud and Schultz (1) and Miller et al. (4) r e p o r t e d that the incidence of mastitis increased with age of cow. McDowell and McDaniel (2) r e p o r t e d f r e q u e n t mastitis in s u m m e r with twice as m a n y t r e a t m e n t s in J u l y to S e p t e m b e r as in April to June. Miller et al. (3) r e p o r t e d that fall calvers may have less mastiffs since t h e y are dry or in late lactation during summer. The objectives of our study were to assess the f r e q u e n c y of clinical mastitis and to d e t e r m i n e effects of sire, lactation number, and m o n t h of calving on f r e q u e n c y of clinical mastitis.
Received August 4, 1976. 1Supported by Ontario Ministry of Agriculture and Food and the National Research Council Grant NRCA6247. 2Animal Research Institute, Research Branch, Agriculture Canada, Ottawa, Canada KIA OC6. 3 Department of Veterinary Microbiology and Immunology.
DATA AND METHODS
The data were lifetime histories for all Holstein cows f r o m 1960 to 1975 at the Elora Dairy Cattle Research Station, Elora, Ontario, Canada. Total n u m b e r of separate cases in each
TABLE 1. Arithmetic means and standard deviations of 10 traits of mastitis infection. Trait Number Number Number Number Number
of of of of of
Proportion Proportion Proportion Proportion Proportion
cases per lactation cases, RF (right front quarter) cases, RH (right hind quarter) cases, LF (left front quarter) cases, LH (left hind quarter) infected infected, infected, infected, infected,
RF RH LF LH
1169
Mean
SD
1.90
3.00
.44 .49 .44 .53
.99 1.06 1.08 1.11
.53 .26 .30 .27 .29
.50 .44 .46 .44 .46
o o
TABLE 2. l n t r a c o w p h e n o t y p i c correlations among mastitis traits.
t~
g < o
g z
©
Proportion infected
N umbe r of cases
Numb er o f Nu mb er o f Nu mb er of Nu mb er of Nu mb er o f Proportion Proportion Proportion Proportion
cases cases, RF cases, RH cases, LF cases, LH infected infected, RF infected, RH infected, LF
RF
RH
LF
LH
Total
RF
RH
LF
LIt
.66
.65 .24
.71 .30 .27
.70 .28 .26 .34
.52 .39 .36 .34 .33
.53 .73 .26 .26 .23 .52
.53 .22 .70 .24 .28 .56 .30
.52 .26 .24 .63 .26 ,51 .35 .30
.56 .28 .26 .29 .68 .54 .35 .37 .34 > > Oq
> TABLE 3. Least-squares analysis of variance of measures of incidence of mastiffs. Mean squares Proportion infected
N u m b e r of cases Source Sires Cows with in sires Parity Months Error *P
INTRODUCTION
Incidence of clinical mastitis in 760 lactations of 331 Holstein cows was studied for effects of sire, parity, and m o n t h of calving. Incidence of clinical mastitis was higher in hind quarters than fore quarters. Positive correlations between n u m b e r of cases in one quarter with n u m b e r in o t h e r quarters and bet w e e n p r o p o r t i o n infected in one quarter and p r o p o r t i o n infected in others indicated that occurrence of mastitis in one quarter was associated with above average frequencies o f mastitis in the o t h e r quarters of the same cow. Clinical mastitis increased with increase in lactation number up to f o u r t h lactation. Cows calving in January and February more f r e q u e n t l y had mastitis than those calving in March and April.
Mastitis reduces milk yield, changes milk composition, shortens productive life o f affected cows, and is costly to dairy farmers. Rendel and Sundberg (5) suggested that f r o n t quarters arc m o r e p r o t e c t e d and less likely to be injured and to contract mastitis. They also r e p o r t e d an incidence of 14.9% in first lactation c o m p a r e d to 37.7% in f o u r t h lactation. Braud and Schultz (1) and Miller et al. (4) r e p o r t e d that the incidence of mastitis increased with age of cow. McDowell and McDaniel (2) r e p o r t e d f r e q u e n t mastitis in s u m m e r with twice as m a n y t r e a t m e n t s in J u l y to S e p t e m b e r as in April to June. Miller et al. (3) r e p o r t e d that fall calvers may have less mastiffs since t h e y are dry or in late lactation during summer. The objectives of our study were to assess the f r e q u e n c y of clinical mastitis and to d e t e r m i n e effects of sire, lactation number, and m o n t h of calving on f r e q u e n c y of clinical mastitis.
Received August 4, 1976. 1Supported by Ontario Ministry of Agriculture and Food and the National Research Council Grant NRCA6247. 2Animal Research Institute, Research Branch, Agriculture Canada, Ottawa, Canada KIA OC6. 3 Department of Veterinary Microbiology and Immunology.
DATA AND METHODS
The data were lifetime histories for all Holstein cows f r o m 1960 to 1975 at the Elora Dairy Cattle Research Station, Elora, Ontario, Canada. Total n u m b e r of separate cases in each
TABLE 1. Arithmetic means and standard deviations of 10 traits of mastitis infection. Trait Number Number Number Number Number
of of of of of
Proportion Proportion Proportion Proportion Proportion
cases per lactation cases, RF (right front quarter) cases, RH (right hind quarter) cases, LF (left front quarter) cases, LH (left hind quarter) infected infected, infected, infected, infected,
RF RH LF LH
1169
Mean
SD
1.90
3.00
.44 .49 .44 .53
.99 1.06 1.08 1.11
.53 .26 .30 .27 .29
.50 .44 .46 .44 .46
o o
TABLE 2. l n t r a c o w p h e n o t y p i c correlations among mastitis traits.
t~
g < o
g z
©
Proportion infected
N umbe r of cases
Numb er o f Nu mb er o f Nu mb er of Nu mb er of Nu mb er o f Proportion Proportion Proportion Proportion
cases cases, RF cases, RH cases, LF cases, LH infected infected, RF infected, RH infected, LF
RF
RH
LF
LH
Total
RF
RH
LF
LIt
.66
.65 .24
.71 .30 .27
.70 .28 .26 .34
.52 .39 .36 .34 .33
.53 .73 .26 .26 .23 .52
.53 .22 .70 .24 .28 .56 .30
.52 .26 .24 .63 .26 ,51 .35 .30
.56 .28 .26 .29 .68 .54 .35 .37 .34 > > Oq
> TABLE 3. Least-squares analysis of variance of measures of incidence of mastiffs. Mean squares Proportion infected
N u m b e r of cases Source Sires Cows with in sires Parity Months Error *P
