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.