Longitudinal study of the effects of teat condition on the risk of new intramammary infections in dairy cows

Abstract

Machine milking-induced alterations of teat tissue may impair local defense mechanisms and increase the risk of new intramammary infections. The objective of the current study was to assess the influence of short-term and long-term alterations of teat tissue and infectious status of the udder quarter on the risk of naturally occurring new intramammary infections, inflammatory responses, and mastitis. Short-term and long-term changes in teat condition of right udder quarters of 135 cows of a commercial dairy farm in Saxony-Anhalt, Germany, were recorded monthly for 10 mo using simple classification schemes. Quarter milk samples were collected from all examined quarters at each farm visit. Bacteriological culture results and somatic cell counts of quarter milk samples were used to determine new inflammatory responses (increase from ≤100,000 cells/mL to >100,000 cells/mL between 2 samples), new infections (detection of a pathogen from a quarter that was free of the same pathogen at the preceding sampling), and new mastitis (combination of new inflammatory response and new infection). Separate Poisson mixed models for new inflammatory responses, new infections, and new mastitis caused by specific pathogens or groups of pathogens (contagious, environmental, major, minor, or any) were used to estimate risk ratios and 95% confidence intervals. Data preparation and parameter estimation were performed using the open source statistical analysis software R. We observed no effect of any variable describing teat condition on the risk of new intramammary infections, inflammatory responses, or mastitis. Intramammary infections of the same udder quarter in the preceding month did not affect risk either.

Quarter- and cow-level risk factors for intramammary infection with coagulase-negative staphylococci species in Swiss dairy cows

“…No classical quarter level covariates (i.e., teat end score, papillomatosis, teat skin lacerations, and so on) were identified to be significant risk factors for speciesspecific CNS IMI in the present study. This is similar to the results of a German study in which no significant associations between teat end condition and new IMI caused by CNS or major mastitis pathogens were identified (Zoche-Golob et al, 2015). In contrast, associations of high teat end scores with a high infection rate of Staph.…”

“…In contrast, associations of high teat end scores with a high infection rate of Staph. aureus (Zadoks et al, 2001), high loads of Streptococcus uberis and Escherichia coli in the teat canals (Paduch et al, 2012;Zoche-Golob et al, 2015), and occurrence of clinical mastitis (Neijenhuis et al, 2001) were described by others. Recently, De Visscher et al (2016) found an increased risk for IMI with Staph, chromogenes, Staph.…”

Bacterial Load of the Teat Apex Skin and Associated Factors at Herd Level

“…However, Guarin et al [10] could not find any association between hyperkeratosis and teat-skin load with environmental pathogens. Zoche-Golob et al [52] could not observe any variable describing teat condition on the risk of developing mastitis. According to our results, coliform bacterial load on teat ends increases as the percentage of cows with normal and healthy teat apices among all lactating cows per herd increases.…”

An update on environmental mastitis: Challenging perceptions

“…Scoring systems have also been developed for teat-end callosity or hyperkeratosis (Shearn & Hillerton, 1996). In a small study (135 cows), teat-end hyperkeratosis was not associated with the risk of mastitis, but a large study (1,667 cows) showed that severe hyperkeratosis is associated with increased risk of E. coli or S. uberis CM, and moderate hyperkeratosis with increased risk of E. coli CM (Breen, Green, & Bradley, 2009;Zoche-Golob et al, 2015). Bacterial loads of both organisms are higher in teat ends with hyperkeratosis than in those without, providing a plausible biological mechanism for the observed association (Paduch, Mohr, & Kr€ omker, 2012).…”