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20131
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Subject: Epidemiology × Author: SOMA SEKHAR REDDY, B × Start date: 1985 ×
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    ThesisItemOpen Access
    EPIDEMIOLOGICAL STUDIES ON SUB CLINICAL MASTITIS IN CROSSBRED CATTLE
    (SRI VENKATESWARA VETERINARY UNIVERSITY , TIRUPATI – 517502. (A.P.) INDIA, 2013-02) SOMA SEKHAR REDDY, B; SHOBHAMANI, B (Major); SREEDEVI, B; NALINI KUMARI, K
    ABSTRACT : To find out the incidence of subclinical mastitis (SCM) 1599 quarter milk samples from 417 apparently healthy lactating cows of seven local organized dairy farms and lactating animals from individual holdings came to Teaching veterinary clinical complex, Tirupati, Andhra Pradesh, were subjected to California Mastitis Test (CMT) and Electrical Conductivity (EC) Test. The quarter wise incidence of SCM as detected by CMT and EC was 27.83 and 19.95 per cent respectively. Whereas the animal wise incidence was 52.28 and 38.13 per cent for CMT and EC respectively. The incidence of SCM in relation to lactation number was highest in fourth and above (53.33%) followed by third (52.94%), first (52.83%) and second (49.45%) lactations as detected by CMT. Whereas the incidence of SCM as per EC was highest in first (43.40%), followed by third (42.48%) lactations, fourth and above (34.17%) and second (32.97%). It was also observed that the fore quarters were more frequently affected (28.87%) than the hind quarters (26.85%). Further, incidence of SCM in relation to stage of lactation was observed in cows in early lactation (51.24% with CMT and 40.50%with EC) than mid (55.07% with CMT and 37.68% with EC) and late (50.63% with CMT and 36.71% with EC) lactations. The mean electrical conductivity readings of infected and uninfected quarters from cows were 270±30 and 360±40 respectively. Taking cultural test as standard, the per cent accuracies of CMT, EC and SCC were 73.33, 70.37, and 71.00 respectively. The false positive reactions were more in CMT(24.60) than SCC (23.70%) and EC (20.4%), whereas the false negative reactions were highest in EC (34.9%) followed by SCC (31.60%) and CMT (28.6%). EC test had the highest specificity (84.84%) and predictive value (79.59%) with lowest sensitivity (56.52%) than CMT and SCC taking cultural test as standard and thus it can be used as the decision criteria to cull or to treat the animals in herds with high prevalence of SCM. Cultural examination of milk from the affected quarters revealed the frequency of isolation of Staphylococci spp (55.12 per cent), Streptococcus Spp(15.61 per cent), E. coli (13.17 per cent), E. coli + Streptococcus Spp (5.17 per cent), Staphylococcus Spp + Streptococcus Spp (3.42 per cent), E. coli + Staphylococcus Spp (4.39 per cent) and pseudomonas Spp (0.98 per cent). In vitro drug sensitivity test was conducted on 425 whole milk cultures which revealed that 28.94 per cent were sensitive to chloramphenicol (123) followed by 24.71 percent ceftriaxone + sulbactum (105), 24.47 per cent ceftrioxone + tazobactum (104), 23.06 per cent gentamicin (70), 20.00 per cent ciprofloxacin(85), 13.88per cent amoxycillin + sulbactum (59),12.71 per cent enrofloxacin(54), 1.65 per cent amoxycillin + clavulonic acid (7), 1.41 per cent ceftizoxime(6), 1.18per cent ampicillin (5),0.94 per cent streptomycin (4), and only few isolates (3) were sensitive to tetracycline(0.71). Based on in vitro drug sensitivity cows of therapeutic trials subclinical mastitic cows in early stage of lactation were divided into five groups. Therapeutic trials were conducted by administering Enrofloxacin, Chloramphenicol, Amoxycillin + Sulbactum, Ceftrioxone + tazobactum, Ceftrioxone + Sulbactum and Ceftizoxime into the affected cows. In Group –I out of 14 subclinically infected quarters from 7 cows subjected to enrofloxacin treatment, milk from 12 quarters from 6 cows were test negative on both CMT and cultural examination on 8th day post treatment, milk from the remaining 2 teats was test negative (CMT, cultural) on 15th day post treatment. In Group-II out of 14 subclinically infected quarters from 7 cow subjected to chloramphenicol treatment, 11 quarters from 6 cows gave negative reaction on both CMT and cultural examination on 8th day post treatment. Milk from 3 quarters from one cow was test negative on 15th day post treatment. In Group-III out of 14 sub clinically infected quarters from 8 cows subjected to ceftizoxime treatment, all the 14 quarters milk samples were test negative on both CMT and cultural examination on 8th day post treatment. In Group–IV, 14 subclinically infected teats from 7 cows were treated with ceftrioxone + Tazobactum, and all the 14 milk samples were test negative with both CMT and cultural examination on 8th day post treatment. Whereas the milk from cows in Group-V was test negative on 7th, 15th day post treatment, with CMT and cultural examination. To find out association between SCM vs. Hypocalcaemia and Hypoglycemia seven cows with SCM + hypocalcaemia were treated (Group –A).Of them, 6,7 and 7 cows were culturally negative on 1st, 2nd and 3rd week post treatment respectively. While 3, 5 and 7 cows had normal calcium levels (9-11 mg. / dl.) during first, second and third weeks post treatment. In Group-C all the 7 cows were culture positive and had low serum calcium levels throughout the study period. In Group-B a total of 7 cows witch SCM and hypoglycemia were treated. Of them, 5 cows were test negative on cultural examination and 3 were cows had normal BHBA values below (1.4 m.mol. /Lt) during the 1stweek post treatment. All the seven cows were test negative for SCM on cultural examination and had normal BHBA on 2ndand 3rd week post treatment. Seven animals in Group – D with SCM and high BHBA values were kept as untreated controls. All the 7 cows were culturally positive and had higher BHBA values (Mean) during the study period (1 to 3 weeks).