HOST DETERMINANTS BASED COMPARATIVE PREVALENCE OF SUBCLINICAL MASTITIS IN LACTATING HOLSTEIN-FRIESIAN CROSS COWS AND RED CHITTAGONG COWS IN BANGLADESH

摘要

A comparative prevalence of sub-clinical mastitis (SCM) based on host risk factors was studied by using California Mastitis Test (CMT) in 96 Holstein-Friesian cross cows (HFCC) of Abu Baker Dairy Farm at Pansha Upazilla in Rajbari district and 20 Red Chittagong cows (RCC) of Bangladesh Agricultural University Dairy Farm (BAUDF), Mymensingh during the period from January to June 2008. Out of the 116 lactating cows examined, 51 (43.97%) showed positive reactivity to CMT. Similar prevalence rate of SCM was recorded in both the HFCC (43.75%) and RCC (45.0%). The overall prevalence of SCM on the basis of lactation stages showed that all the three lactation stages had SCM but there was a tendency to increase its prevalence rates from early (30.43%), mid (32.26%) to late (69.23%) stages. The highest prevalence of SCM was recorded at late lactation stage in both the HFCC (68.75%) and RCC (71.43%) in comparison to their respective mid and early lactation stages. The parity-wise prevalence of SCM was recorded as 18.42%, 55.0%, 66.67%, 75.0% and 75.0% in HFCC whereas, it was 20.0%, 20.0%, 66.67%, 75.0% and 66.67% in RCC at their 1st, 2nd, 3rd, 4th and 5th parity, respectively. This study recorded a relationship between the increased prevalence of SCM with decreased of milk production in both the groups of lactating cows. The respective prevalence of SCM at high, medium and low level of milk production in HFC (14.29%, 33.33% and 70.59%) and RCC (14.29%, 50.00% and 71.42%) were found significantly (p 0.01) correlated with milk production. An overall 19.18% quarters was affected with SCM, of which 4.31%, 7.33% and 7.38% showed mild, moderate and severe reaction to CMT. However, comparatively, higher percentage of quarter infection was recorded in HFCC (20.31%) than RCC (13.75%). It may be concluded from these observations that both the HFCC and RCC should be monitored by using CMT for the detection of SCM in order to provide rational treatment and control it to make the dairy farming profitable.