Udder and teat morphometry and its relationship with occurrence of intramammary infections in dairy cattle

Abstract

Bovine mastitis, an inflammatory disease of the mammary gland, is often caused by bacterial infection and is a major health problem on dairy farms. A cross-sectional study of four herds was conducted to assess udder and teat-related risk factors for the development of intramammary infections in 243 lactating cows. Udder and teat morphometric parameters were determined through visual appraisal method. Intramammary infection was assessed using California mastitis test (CMT), Somatic cell count (SCC) and bacteriology of milk samples. The frequencies of udder conformations were 65.8%, 18.9%, 7.4% and 7.8% for desirable, pendulous, round and goaty-shapes, respectively. Teat conformation revealed that 76.0%, 5.3%, 6.6%, 4.5% and 7.5% for desirable, short, funnel, bottle and conical-shapes, respectively. There was a significant (p<0.01) effect of udder shape and teat-end shape on SCC level and intramammary infections. The mean SCC and mastitis infection levels for undesirable udder was significantly (p<0.05) higher as compared to the desirable shaped udder. Similarly, significant (p<0.05) higher level SCC was found in undesired teats compared to desirable teats. The overall proportion of quarter mastitis infection in all four farms revealed 1.23% for clinical and 36.52% for subclinical mastitis. Herd-wise subclinical mastitis prevalence showed 42.8%, 35.07%, 33.09% and 2.94% for farm A, C, B and C, respectively. The most frequently isolated bacterial species were Staphylococcus aureus (56.34%) followed by Escherichia coli (22.55%), Streptococcus agalactiae (9.86%) and Bacillus spp. (8.45%). In conclusion, undesirable udder and teats conformations were more susceptible to intramammary infection and these traits must be considered accordingly while selecting dairy animals for future milk production. Observed high occurrence of subclinical Staphylococcal mastitis needs improvements in milking hygiene, mammary gland health, regular screening of animals, and use of biosecurity as an intervention tactic to limit the spread of pathogens at dairy farms.