STUDIES ON HISTOLOGY AND MICROBIOLOGY OF TEAT AND STREAK CANAL AND THERAPEUTIC EFFICACY OF PARTIAL VS FULL INSERTION OF ANTIBIOTIC SYRINGE CANNULA IN BUFFALOES AND COWS

Abstract

The present study was undertaken to determine the comparative prevalence of streak canal infections in buffalo and cow and to determine the comparative dimensional features of streak canal these two dairy species. In addition, comparative efficacy of partial or full insertion of teat cannula of a dry period antibiotic formulation in buffalo and cow was determined. Duplicate streak canal swab and quarter foremilk samples taken from 20 lactating buffaloes and 20 lactating cows were cultured and isolates identified. Length and width of streak canal of buffalo and cow (n = 20 each) was determined by Vernier caliper after incising the teats collected from abattoir. An in vivo comparative radiographic analysis of streak canal of buffaloes and cows (n = 20 each) was performed after infusion of 0.25ml of 5% barium sulphate into each teat followed by radiographic imaging and measurement of streak canal length and width from the image. In another phase of the study, efficacy of partial insertion vs. full insertion of teat cannula of a commercial cephapirin benzathine dry period antibiotic formulation (Cefa-Dri®) in the prevention of new intramammary infections and treatment of existing infections was evaluated on 20 buffaloes and 20 cows. Results: Seventy three (91.25%) and 59 (73.75%) of streak canal swab samples of cow and buffalo respectively were found infected. Staphylococcus aureus was the most frequent isolate both in cow and buffalo accounting respectively for 34 and 18 of total isolates (n = 106 for cow; n = 78 for buffalo) recovered from streak canal. Forty four (55%) and 18 (22.5%) of quarter foremilk samples of cow and buffalo respectively were infected. Staphylococcus aureus was the frequent isolate recovered from milk samples of both cows and buffaloes accounting respectively for 25.49% and 18.18% of total milk isolates. The mean values of streak canal length determined by Vernier caliper in cow and buffalo respectively were 9.78 ± 1.20 and 9.96 ± 1.44 mm whereas the mean width was 0.9 ± 0.12 and 0.98 ± 0.23 mm; both dimensions being non significantly different in the two dairy species. The mean length (9.34 ± 1.01mm) of streak canal of cow determined from radiographic image differed non- significantly (p = 0.105) from the mean length (9.97±1.36mm) of streak canal of buffalo. Similarly, mean width of streak canal of cow (0.9±0.09mm) differed non-significantly (p = 0.192) from the mean width of streak canal of buffalo (0.94±0.10mm). Thickness of epithelium of streak canal of buffalo (357.19 ± 4.8μ) was highly significantly (p = 0.001) more than thickness of epithelium of streak canal of cows (327.25±5.91μ). Similarly, thickness of keratin layer of streak canal of buffalo (154.7±6.34μ) was highly significantly (p = 0.001) greater than the thickness of keratin layer of streak canal of cow (101.3±4.11μ). As also was the case for muscle sphincter thickness around streak canal. Fürstenberg’s rosette folds were highly significantly (p = 0.001) thicker in buffalo (13.4±0.12) than in cow (12.75±0.2). Mitotic index of streak canal of cow and buffalo also differed significantly (p = 0.038); being greater in cow than in buffalo. Seventeen new intramammary quarters infections were detected in 40 quarters of cows treated by full insertion of dry intramammary treatment syringe (Cefa-Dri®, Forte Dodge, USA) cannula. The corresponding figure for 40 cow quarters treated by partial insertion of the same antibiotic dry period formulation was 6. Nine new intramammary infections developed over dry period in 40 quarters of buffaloes treated by full insertion of treatment syringe (Cefa-Dri®, Forte Dodge, USA) cannula. The corresponding figure for 40 buffalo quarters treated by partial insertion of the same antibiotic dry period formulation was 3. A total of 20 quarters of 10 cows were found infected by various mastitis pathogens at drying off in full insertion treatment group. Thirteen of these quarters were found cured after calving as no organism could be isolated from samples collected at calving and those collected biweekly for 3 months after calving. In the partial treatment group, of the 22 quarters, 18 were cured. Thus the cure rate (81.8%) in the partial insertion treatment group was significantly higher than in the full insertion treatment group in cows. Ten of the 14 (71.4%) infected quarters of buffaloes were cured when Cefa-Dri® intramammary tube was used by full insertion method. The corresponding cure rate by partial insertion of the same intramammary preparation was 84.6% (11 of 13 infected quarters being microbiological negative at calving as well as 3 months following calving of buffaloes). All in all, the results of comparative histomorphological examination of streak canal of cow and buffalo as well as the results of comparative efficacy trial of partial vs. full insertion of cannula of dry period antibiotic treatment syringe suggest that both the dairy species should be treated at drying off by using partial insertion of dry period intramammary antibiotic formulation.