CHARACTERIZATION OF THE BACTERIAL COMMUNITIES LOCATED ON THE SKIN SURFACE OF DIGITAL DERMATITIS AND FOOT ROT LESIONS OF FEEDLOT CATTLE
Date
2024-01-23
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0009-0005-1565-7640
Type
Thesis
Degree Level
Masters
Abstract
As a major health problem in feedlots, lameness has significant economic and welfare consequences. Infections in the hooves are a major source of lameness in feedlot cattle. Foot rot (FR) is a highly prevalent hoof disease that affects the interdigital space between the claws. Digital dermatitis (DD) is another important hoof disease that typically manifests as skin lesions between the dew claws on the back of the heel, which can have different presentations as they develop through a series of morphological (M) stages. Both FR and DD are painful, contagious, and are major contributors to feedlot lameness, posing operational and production challenges related to their treatment and control in the feedlot industry. In addition, both hoof diseases have a bacterial origin and can concurrently affect the same hoof (DD+FR). The main objectives of this thesis were to: 1) characterize the hoof lesion bacterial communities of DD, FR, and a combination of both (DD+FR) and 2) characterize and compare the bacterial communities of two active DD stages (M2 and M4.1). Bacterial communities investigation was accomplished using 16S rRNA amplicon sequencing of surface hoof swabs collected from cattle in three southern Alberta feedlots. Analysis of hoof swabs revealed that the DD, FR, and DD+FR bacterial communities were distinct from the bacterial communities of the healthy control skin. The novel characterization of mixed bacterial communities of a DD+FR combination lesion was presented for the first time. Fusobacterium, Prophyromonas, and Peptostreptococccae were associated with FR, DD, and FR+DD, suggesting bacterial overlap in lesion communities. Although M2 and M4.1 lesions each were independently different from M0 skin, no significant diversity and bacterial communities differences were observed between the two active lesion stages. There were similar increases in Spirochaetota and Fusobacteriota relative abundances and alpha diversities in the communities of these two DD stages when compared to M0 control skin. In addition to bacterial communities of both lesion stages sharing multiple common taxa, the lack of alpha, beta, and phylogenetic differences suggest that the bacterial communities appear stable across active lesion stages. These findings contribute to the polybacterial understanding of complex hoof lesions through a non-invasive surface swabbing method.
Description
Keywords
hoof lesions, 16S amplicon sequencing, beef cattle, lameness, swab
Citation
Degree
Master of Science (M.Sc.)
Department
Western College of Veterinary Medicine
Program
Large Animal Clinical Sciences