Massey research update

MASSEY UNIVERSITY RESEARCH UPDATE

Gains in reducing pain

Massey University School of Veterinary Science PhD candidate Farzin Sahebjam has developed a novel method for prolonging analgesia among deer after velvet antler removal.

BACKGROUND AND SCOPE

The New Zealand deer industry is growing quickly, thanks largely to exports of velvet antler and the production of venison. In the year ending 30 September 2018, the total value of velvet exports from New Zealand was estimated at $65 million (Deer Industry New Zealand, 2018), and demand for velvet antler has led to an increased demand for stag production.

There are still some animal welfare concerns about velvet antler production, in which pain can be as severe as that felt after a limb amputation (Wilson and Stafford, 2002). The current practice is to inject the short-acting local analgesic lidocaine around the antler pedicle, and the drug is licensed to be administered just before the procedure. However, this pain relief can only last for about 90 minutes. In my study I’ve been able to demonstrate that deer regain the sensation of pain as soon as one hour after the procedure.

To date, no licensed protocol or product has been developed to alleviate pain following velvet antler removal in deer. For this reason my PhD project aims to develop a new analgesic drug for use in velvet antler removal. I used the deer model to figure out how to cover and coat local anaesthetic drugs, causing a slower release than usual and therefore prolonging their effects.

SIMULATION IN THE LAB

Initially I faced many challenges and had to work in a multidisciplinary way to bring together all aspects of the research. A year into my study I learned how to extract and change the structure of biocompatible materials from industrial waste products to make my formulation. I focused on using waste products to not only reduce cost but also minimise the environmental impacts of the industry.

The next stage involved a series of tests to assess and validate the functionality of the novel formula. My colleagues and I needed to establish first whether our drug could be released from the biocompatible structure, and second

how quickly it was released. The best analogy for the structure of the drug is a sponge with tiny holes in it, through which the drug molecules slowly disperse and arrive at the surface to start acting on the tissue.

Before involving any animals I conducted tests in the laboratory that simulated the deer physiology. In vitro studies are not always representative of animal studies, but they can be very helpful in mapping research plans and collecting numbers to interpret and justify products’ effectiveness. In my in vitro study I used an apparatus called a Franz diffusion cell, a gold-standard method, to test the efficacy of the drugdelivery system.

The results from the lab tests were promising, with the drug-release patterns showing an obvious slower release of the drug I had formulated compared to the ones conventionally used without a coating to control release.

TIME TO TRY THE FORMULATION ON DEER

We next obtained approval from the Massey University Animal Ethics Committee to trial the new formulation on deer. With the help of my supervision team, we designed a wafer-thin pad that could be easily manufactured and conveniently applied on deer antlers in a farming situation. We then undertook further assessments, such as using thermal imaging to ensure that our product did not elicit any additional inflammation or adverse reactions and was safe to be used on animals.

Our trial was conducted at the Massey University Deer Research Unit and involved 40 stags divided into four groups, each containing 10 animals. Each group was treated differently: the animals in the control group were injected with conventional lidocaine before velvet antler was removed; the other three treatment groups each received lidocaine injections before antler removal, then one of three treatment pad types once the antler was removed. It was important to apply the pads instantly to the antler wound surfaces to let the pads absorb blood and release the anaesthetic agents into the underlying tissue.

We observed that the pads stayed attached to the antlers for up to one month after application. Pain was quantified with a force-detection device called an algometer, and measurements were taken at regular time intervals, enabling us to plot the animals’ behavioural reactions to our device.

In my observations, and after statistical analysis, we concluded that up to 10 hours of pain relief was detected. We had produced a product that could revolutionise animal welfare through more effective pain management after surgical manipulation.

GETTING PREPARED TO TAKE THE PRODUCT TO MARKET

My hope is that the product developed for my PhD can be commercialised and made available in the market soon, thus helping animals as soon as possible. Currently the product is in the preliminary stages of patenting.

Along with the animals, veterinarians, farmers and the deer industry will benefit hugely from this innovation, which presents a great step in the betterment of animal welfare and pain management. Other animal species, both large and small, could also potentially benefit from the product with further development.

I am grateful for all the support I have received from Massey University, the Ministry of Business, Innovation and Employment, the NZ Leather and Shoe Research Association as well as my supervisors.

REFERENCES:

Deer Industry New Zealand. At a Glance Industry Statistics. https://www.deernz.org/about-deerindustry/nz-deer-industry/deer-industry-statistics/ glance-industry-statistics#.XzMxgxMzZTY (accessed 21 July 2020). Deer Industry New Zealand, Wellington, New Zealand, 2018

Wilson P, Stafford K. Welfare of farmed deer in New Zealand. 2. Velvet antler removal. New Zealand Veterinary Journal, 50(6), 221–7, 2002

PhD candidate Natalie King compiles research projects underway at Massey University.