Molecular Screening for Digital Dermatitis-Associated Treponemes in Bovine Ischaemic Teat Necrosis Lesions and Milk in Dairy Cattle

Abstract

Bovine ischaemic teat necrosis (ITN) is a disease affecting the skin of the teats of dairy cows with an unknown aetiopathogenesis. Digital dermatitis (DD)-associated treponemes have previously been suggested as a potential aetiological agent in ITN, although the sample size was small. The current study, using established PCR techniques, aimed to examine the association with the presence of DD-associated treponemes in a large number of ITN samples from a wider geographical area, and surveyed the potential of milk as an infection reservoir. From 95 ITN lesions, 35.8% (n = 34) were positive for at least one DD-associated treponeme compared with only 5.6% (n = 1) of 18 non-lesioned teats from cows with ITN lesions on a different teat using a nested PCR approach. All 10 age- and production-matched control cows were negative for DD-associated treponemes via PCR. No DD-associated treponemes could be detected from foremilk of cows with (n = 19) and without (n = 31) a DD lesion on the hind feet. DD-associated treponemes could be detected via PCR after incubation in milk for up to 2 h. Therefore, milk does not appear to be a competent reservoir for transmission of DD-associated treponemes. Moreover, in the current study DD-associated treponemes were only detected in a subset of ITN samples, so it is unlikely these opportunistic skin-associated pathogens are the major or sole agent of ITN.

Clinical Presentation, Bacteriologic Findings and Possible Risk Factors for Ischemic Teat Necrosis in Cattle—A Case Series

“…was performed, as Treponema spp. are the most discussed factor in the existing literature [ 3 , 4 , 5 , 6 ]. However, detection of Treponema spp.…”

“…In particular, Treponema spp. causing digital dermatitis have been considered a risk factor [ 3 , 4 , 5 , 6 ]. In a very recent study by Crosbi-Durrany et al [ 6 ], Treponema spp.…”

“…causing digital dermatitis have been considered a risk factor [ 3 , 4 , 5 , 6 ]. In a very recent study by Crosbi-Durrany et al [ 6 ], Treponema spp. were detected in 35.8% of cases in 95 teats with ITN.…”

“…However, the authors concluded that Treponema spp. were only found in some of the samples and therefore cannot be considered the most important or sole etiologic factor [ 6 ]. A survey from Germany in 2016/2017 reported that several animals on two farms were affected by ITN, particularly in the first lactation and at the beginning of lactation.…”

“…As the disease seems to occur predominantly in heifers at the beginning of lactation and various risk factors are discussed [ 3 , 4 , 5 , 6 , 7 ], both non-infectious and infectious factors appear to play a role in the development of ITN.…”