Hartpury College Research Takes the Pressure Off Dog Walking with HBM Miniature Load Cell

Potential dangers of excessive forces from collars

Dog owners usually share an extremely close relationship with their pets, and hence would be interested in knowing that dog injuries can occur due to the constant force exerted by collars or harnesses. Prong collars or choke chains have the potential, as a result of excessive force, to cause mechanical or ischemic damage to the brain, thyroid, trachea, larynx and esophagus. The propensity for increased intraocular pressure due to excessive compression on the jugular vein is also present. Although considered kinder for animals, there is limited evidence available about the injuries caused to areas such as front limbs, chest or across back due to the amount of force applied by harnesses. It has also been anecdotally suggested that a harness changes the natural gait of a dog. As a result of that, it is equally important for dog owners to be aware of the potential problems that their dogs might face, such as undue pressure and force on their bodies and joints, injuries, and even chaffing, due to ill-fitting harnesses. With these important warnings in mind and no concrete information available on how these restraints affect the gait of a dog or the force exerted when in motion and most importantly which type of restraint is better, HBM supplied the key piece of equipment which could help solve the puzzle.

Analyzing the degree of forces excerted on the lead

To identify whether there is a significant difference in the gait of a dog when it is exercised using either a collar or a harness and to analyze the degree of force exerted on the lead by the handler and the dog, Hartpury College specified the U9C miniature load cells from HBM to collect data on the amount of force experienced at the site of the dog’s restraint. The compact and cost-effective U9C series reliably measures tensile and compressive force where space is a constraint, which was a key consideration in these trials. Enabling dynamic and static measurement tasks to be solved, its high fundamental frequency also makes it suitable for very fast measurements. Manufactured in stainless steel and featuring a welded design, the U9C is a robust sensor, which was the ideal choice for such a challenging application. By incorporating strain gauges onto the dog’s harness and lead, Hartpury College were successfully able to achieve the desired measurements for both the dog and the handler. To make the design more robust, the transducer was sewn into a one meter lined fleece that enabled the gauge to be fixed to the D ring of the collar or harness. This gauge was then connected to a four port express DAQ connected via USB to a laptop. The software for analysis, also supplied by HBM, provided the data from both the handler and the dog in numeric data (Hz) pull from each of the trials as well as in graph form. Suitable for challenging applications, catman data acquisition software, which allows data visualization, analysis and storage during the measurement and reporting process, enabled the raw data to be transferred to a spreadsheet and to be analyzed with the SPSS statistical analysis software. With the strain gauge and the lead attached to the collar, the handlers walked and trotted dogs, and the process was then repeated with dogs wearing a harness instead.

The result

The results collated from the study proved that when using the particular types of collars and harnesses used in the study, there is no difference in gait when the dog is walking or trotting in a harness. It also proved that the force exerted to the neck and throat when wearing a collar is more localized and has the potential to cause damage or exacerbate existing injuries, while the force exerted when wearing a harness is distributed over a larger area, which reduces the impact of the force. The data collected can be used by concerned pet owners to make a more educated decision regarding their dogs.