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Subject: search.filters.subject.Dogs as laboratory animals

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    Tonic immobility by dogs : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science in Veterinary Ethology at Massey University
    (Massey University, 1993) Ong, Rae Ming
    Tonic immobility (TI) is a state of relative immobility induced by restraint and presumed to function as a terminal defensive reaction. Although TI has been reported in a wide spectrum of species ranging from invertebrates to mammals, there have been very limited studies on TI by dogs. The aim of this thesis was to determine the susceptibility and characteristics of TI in dogs so that the feasibility of using TI as a humane, quick, easily reversible, non-chemical and safe method of restraint for veterinary procedures could be assessed. In an initial survey, 132 dogs were tested twice. Once by inversion and 30s restraint in the lateral position and once with an additional treatment (stroking, scruffing, blanket over head, cuff around ears or light into eyes) during the 30s restraint. Based on the criterion of remaining in the position restrained, without lifting its head off the test surface, for a minimum of 10s after release from restraint, 10 of the 132 dogs (7.6%) exhibited TI. The characteristics of the dogs during TI were similar to those reported in other species, as the dogs remained very still, with the exception of occasional repositioning of heads and limbs, muscle tremors, twitches and paw movements. Swallowing, lip licking, blinking and occasional periods of eye closure were also observed but dogs had their eyes open throughout most of the TI episodes and appeared to be continually monitoring their environment as eye and ear movements, muscle twitches and changes in respiration rate were observed in response to auditory and other stimuli. Many TI episodes were not terminated by intense stimulation such as loud auditory stimuli or physiological testing that included pinching between the dog's toes and inserting a thermometer into the dog's rectum. Respiration rate, heart rate, withdrawal reflexes and temperature were monitored on these dogs. These physiological parameters were all within normal limits. Susceptibility to TI appeared to be a dog effect rather than a technique effect. Timid dogs or dogs that eliminated during testing were more susceptible to TI, indicating that susceptibility may be related to the dog's temperament or fearfulness. It was also found that proestrous bitches were more susceptible to TI than the other dogs. A potentiation effect with repeated testing was observed when the intertrial interval was between 20-80s. No order or carry-over effect was however found when a 3 min intertrial interval was used. No difference in susceptibility to TI was found between techniques but the cuffing technique resulted in longer TI durations than the others. Results should however, be interpreted with caution due to the small number of dogs exhibiting TI. More extensive investigations of the characteristics and physiological changes during TI and the effect of individual variables on TI susceptibility and durations are also required to determine the safety and extent of procedures that may be conducted while dogs are in TI. The results from this initial study are promising as they show that dogs do exhibit TI. The duration, characteristics and physiological changes observed during TI also indicate the potential for using TI as a quick, non-chemical, easily reversible and safe method of restraint in some dogs, for routine clinical examinations or even veterinary procedures.
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    The rat as a model animal for digestion in the dog : a thesis presented in partial fulfilment of the requirement for the degree of Master of Science in Nutrition at Massey University
    (Massey University, 1998) Sritharan, Kugappiriyai
    The suitability of the laboratory rat as a model animal for studying protein digestion in the dog was investigated. The work was conducted in two experiments. In the first study ileal and faecal endogenous excretion of amino acids and nitrogen was measured in adult rats and dogs. Two groups of five adult dogs (two females and three males) and two groups of six adult rats (three males and three females) were fed either a protein-free (PF) or enzyme hydrolysed casein (EHC)-based diet, containing Cr O as an indigestible marker. After an 8-10 d equilibration period, 4½ h after the start of hourly feeding, the animals were euthanased and the ileal content was collected from the terminal 20 cm of the ileum and freeze-dried. Faecal digesta samples of the rats and dogs fed the PF diet were obtained one day before digesta sampling from the terminal ileum. The freeze-dried digesta collected from the EHC fed animals were ultrafiltrated before analysis. The amount of endogenous amino acids and nitrogen excreted per gram of dry matter intake at the end of the ileum for the PF and EHC fed animals and over the entire digestive tract for the PF fed animals were determined. Data were analysed using ANOVA with species, diet and the interaction between species and diet as variables. There was no interaction between species and diet on the endogenous ileal excretions of any of the amino acids or nitrogen. Significant (P < 0.05) higher endogenous amino acid and nitrogen excretions were found in the dogs compare to the rats when fed the PF and EHC-based diet. Faecal endogenous excretions were higher than ileal endogenous excretion in both species for all amino acid. The pattern of endogenous amino acid excretions was similar in both species with the endogenous excretions of amino acids measured by the ultrafiltration method significantly (P < 0.05) higher than the PF method in both species. In the second experiment the digestibility of a commercial dry dog food was compared between the rat and the dog. A group of five adult dogs (three females and two males) and six adult rats (three females and three males) were fed a commercial dry dog food, containing Cr O as an indigestible marker for 10 and 8 days, respectively. On the final day, 4½ h after the start of hourly feeding, the animals were euthanased and the ileal content was collected and freeze-dried. A faecal sample was collected from each animal one day before ileal digesta sampling. The diet and digesta samples were analysed for amino acids, nitrogen, organic matter and the apparent digestibility of dry matter, organic matter, nitrogen and amino acids were determined at a faecal and ileal level. The true ileal digestibility of nitrogen and amino acids were calculated and all the data were analysed using ANOVA. In the dog, the apparent faecal digestibility of aspartic acid, threonine, serine, proline, glycine and total nitrogen was significantly (P < 0.05) higher than the apparent ileal digestibility values whereas for methionine the apparent ileal digestibility value was significantly (P < 0.05) higher than the apparent faecal digestibility value. Apparent and true ileal digestibility for most amino acids were significantly (P < 0.05) higher in the dog when compared to the rat. Regression analysis showed that there was a significant (P < 0.001) linear relationship between the apparent and true ileal digestibility of amino acids between the rat and the dog. Ileal digestibility of amino acids in the dog (Y) could be predicted from respective rat values (X). The following equations were obtained for apparent digestibility: Y = 0.32 + 0.65 X and true digestibility: Y = 0.45 + 0.53 X. The present study showed that the rat may be a useful model for studying protein digestion in the dog. However, to make a more general conclusion regarding the use of the rat as a model animal to study protein digestion in the dog, a wider range of dog foods need to be investigated to determine the "strengths" of the regression equation shown above.