The potential role of shearing load in the development of toe tip necrosis syndrome

Toe tip necrosis syndrome (TTNS) is defined as a hind limb lameness disorder of feedlot cattle. TTNS is characterized by separation of the white line, necrosis of the third phalanx (P3) and abscess formation. The reason for white line separation with TTNS is unclear. One potential cause is that cattle, due to environmental conditions, damage the white line by scuffing their hooves on abrasive surfaces found in feedlots. This may result in small pathways for external biological materials and bacteria to enter the hoof, causing infection and initiation of TTNS. Also, an abraded worn claw may be more susceptible to local damage caused by small particles, further increasing potential for pathways to develop. The objectives of this study were: 1. Compare local stiffness along the white line of abraded claws and control claws. 2. Compare contrast-enhanced HR-pQCT image-based metrics of damage and pathway development of abraded claws, control claws and claws with TTNS. 3. Compare overall stiffness of abraded claws, control claws and claws with TTNS. Abrasion testing was performed on the lateral digit of healthy specimens. Local indentation stiffness testing was performed on these specimens as well as control specimens manually rasped to the same level of wear found with abrasion. Following that, the claws were submerged in a contrast agent and underwent suction. Specimens were then imaged using High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT). Images were segmented, with measures of mean intensity acquired. Estimates of overall stiffness were also acquired using load-displacement curves. State statistics were used to compare local stiffness, mean intensity and overall stiffness. Our results indicated a significant difference (p-value < 0.05) between local stiffness of abraded claws and control claws. Our findings also indicated differences in the mean intensity between these two groups. In addition, local damage was observed in HR-pQCT scans of abraded claws, whereas there was no evidence of local damage with control claws. Furthermore, we found that mean overall stiffness of abraded claws was similar to that of claws with TTNS and lower than control claws. These findings support the idea that abrasion is involved in TTNS pathogenesis.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Saskatchewan

Year dc:date.issued

2023

Author dc:creator

• Hedayati, Nassim

Advisors dc:contributor.advisor

• Johnston, James D
• Jelinski, Murray

Committee members dc:contributor.committeemember

• Noble, Scott
• Erickson, Nathan
• Clark, Chris

• TTNS
• Bovine claws
• Mechanical properties
• Shearing load

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10388/14692

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/14692