Hauser et al. [ 5 ] studied the behaviours of 40 dogs during veterinary examinations in a randomised, crossover, double-blinded, placebo-controlled trial. DEXO oromucosal gel reduced vocalisations, avoidance behaviours, panting, trembling, urination and defaecation.
In a crossover study, Amat et al. [ 19 ] examined the effectiveness of DEXO for preventing nausea and stress in connection with a 10-minute car journey 2 hours after receiving DEXO. Amat et al. [ 19 ] also examined fear reduction after exposure to sound in sound-sensitive dogs using a dose of DEXO of 125 µ g / m 2 body surface area, and found a decrease in tremors, panting, urination / defaecation, escape attempts and need to curl up and hide.
Korpivaara et al. [ 20 ] showed lowered noise-associated acute anxiety and fear, with decreased tremors, panting, restlessness, vocalisation and inappropriate urination, in 182 dogs. The study was conducted on New Year ' s Eve( when fireworks are commonly used) in 2012; in this study, the DEXO preparation was perceived as easy to administer by 84.6 % of users. In another study, Korpivaara et al. [ 21 ] reported improvement in the ability to perform a physical examination and a short minor veterinary or husbandry procedure in a study with 74 dogs previously reported to show fear and anxiety during veterinary visits, given doses of DEXO of 125 and 250 µ g / m 2, and also found significant reductions in the HR of the dogs.
An oromucosal gel with the active ingredient detomidine, another alpha-2 agonist, has also been tried in horses. In eight horses treated to alleviate acute noise-related anxiety and fear on New Year ' s Eve, the placebo group overall showed more restlessness, vocalisation and signs of colic [ 25 ].
The effect of FSAR has not previously, to our knowledge, been validated. Our study does not support the use of Aptus Relax as a PVP in the kind of setting used in the trials.
Behaviours were assessed only at the three sessions where the medications were tested, not during the two baseline sessions. Both dogs with the highest floor interaction score during DEXO treatment(‘ pink’ and‘ purple’) scored highest at their first session, then lower for each treatment session. This could have been due to adaptation, despite no sign of habituation in their physiological parameters.
The time from administration to each assessment varied slightly, to increase the study efficiency. The shortest time that elapsed between the administration of DEXO and the assessment was 42 min, long enough to allow the product to take effect. Other studies have demonstrated effects while using varying timings of administration of DEXO, for example, 2 hours before car travel [ 19 ], or either 1 hour in advance of expected signs of stress or when signs started to occur [ 20 ].
Stress evaluation parameters
The clinical examination was designed to mimic a normal visit to a veterinary clinic and expose the dogs to a situation with several moderate stressors. The health-check parameters selected served the dual purpose of both creating the visit-stimulated stress and measuring it. RR, HR, MAP and body temperature, all of which increase during stress due to the activation of the sympathetic nervous system, are good quantifiers of stress surges.
According to Gomart et al. [ 26 ], measuring the rectal temperature in a dog induces more stress reactions( increase in HR, defensive behaviour, lip licking and vocalisation) compared with measurement of auricular or axillary temperature, with a sex difference( females showed a smaller difference in stress reactions than males), and this suggests that axillary( and, to a lesser extent, auricular) temperature measurement is a reliable, less stressful alternative to rectal temperature measurement in dogs. In the current study, rectal temperature measurement was chosen because it is a very common practice at regular veterinary visits. DEXO has previously been shown to have a small and dose-dependent temperature-lowering effect. Rectal temperature variations were, however, limited and close to or within the margin of error( 0.1 – 0.2 ° C) of the digital thermometer, and thus not informative.
MAP was measured five times in succession, as is recommended to ensure a credible result [ 27 ]. The five readings were taken over 2 – 3 minutes, during which the dog was held by the dog handler, with a cuff on the tail, making this part of the examination potentially the most stress-inducing.
Our data on RR are somewhat unreliable. According to the protocol, a result needed to be obtained within a 5-minute time span by the VN by counting breaths for 15 seconds. Several observations were dismissed after 5 or 10 seconds, when dogs were unable to stay still or were sniffing, hissing or panting, especially at baseline 1. Listening to the lungs with a stethoscope would have increased the accuracy of RR measurement. However, visually counting breaths allowed evaluation of the dog before it had any physical contact with the VN( RR1), and the RR would likely increase from physical manipulation.
Four RR data were excluded: those for dog‘ brown’ for moving and sniffing excessively after a dose of DEXO, and‘ black’ due to panting after being given FSAR. Panting not only makes RR difficult to establish; it is also often classified as a behavioural change rather than a physiological one, in contrast to HR, blood pressure and cortisol levels [ 7, 10, 28 ]. Therefore, it could optionally have been included in the analysis of behaviour. There was a non-statistical tendency towards lower RR after administration of DEXO.
24 Veterinary Nursing Journal