Browsing by Author "Aviles-Rosa, Edgar O."
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Item An Automated Canine Line-Up for Detection Dog Research(2021) Aviles-Rosa, Edgar O.; Gallegos, Shawna F.; Prada-Tiedemann, Paola A.; Hall, Nathaniel J.Currently, there is a need to develop technology that facilitates and improves detection dog research. The aim of this research was to develop an automated computer-driven olfactory line-up task. The apparatus consisted of three olfactometers. Each olfactometer was equipped with flow meters to regulate air flow and dilution and six solenoid valves connected to odor jars. Each olfactometer generated an odor which was carried to an odor port where the dogs sample it. The olfactometer's valves were activated by a microcontroller, and a Python program was built to control each olfactometer and randomize and balance the odor presentation. Dogs (N = 12) received one or two 40-trial training sessions in a day where they progressed through a series of training phases where they learned to detect and alert to double-base smokeless powder (SP). An “alert” consisted of a 4-s nose hold. This was measured by infrared sensors in the ports. For each trial, the apparatus recorded dogs' search latency, sniff time, port entries, and response. All this information was automatically recorded in a csv file. A photoionization detector (PID) and solid-phase microextraction followed by gas chromatography-mass spectrometry (SPME-GC/MS) were used to evaluate the odor dynamics and to instrumentally verify odor presence and clearance. A control test was conducted at the end of the training to ensure dogs were alerting exclusively to the odorant. All 12 dogs readily learned to operate the apparatus within 23 days, and all exceeded 85% accuracy. Control tests indicated dogs were leveraging only olfactory cues and not unintentional cues such as auditory cues from the apparatus. Analytical data showed that odor was detected in the port immediately after the activation of a valve and that odor clearance occurred immediately after the valve was closed. The apparatus developed was easy to operate by the dogs and allowed substantial data collection using double-blind testing procedures in a very short period at an affordable cost point for research equipment (~$5,000 USD). The apparatus may prove to be a useful research tool to provide optimal odor stimuli control, ensure double-blind conditions, reduce labor, and significantly increase the amount of data collected.Item The effect of swine's semiochemicals on pigs' behavior, physiology and production(2019-05) Aviles-Rosa, Edgar O.; McGlone, John J.; Hall, Nathaniel J.; Rakhshandeh, Anoosh; Thompson, Jonathan E.; Surowiec, KazThe objectives of this doctoral dissertation were to 1) evaluate how coprophagy benefits piglets, 2) the identification of maternal semiochemicals that might be acting as a fecal maternal pheromone, and 3) to evaluate if putative maternal semiochemicals (FMS) could be used to improve wean pig welfare and performance. The effect of coprophagy on nursing piglet hematology, behavior, and performance were assessed by depriving piglets of maternal feces the first seven days of age. Deprivation of maternal feces had no statistically significant effect on piglet behavior, RBC, HCT, and Hb (P > 0.05). Piglets with access to maternal feces (control) had better pre- and post-weaning performance than piglets deprived of maternal feces for the first seven days of age. Deprivation of maternal feces reduced piglets average daily gain and feed intake by 10 %. Piglets with access to maternal feces the first seven days of age weighed 9.6 kg more at 123 d post-weaning compare to the ones deprived of maternal feces the first seven days of age (P < 0.05). To identify fecal maternal semiochemicals that might be acting as a maternal fecal pheromone and inducing coprophagy, fecal samples were collected from eight sows during gestation and lactation. Fecal semiochemicals were extracted with a SPE procedure and analyzed by GC/MS. Results showed that lactation increased the fecal concentrations of skatole and myristic acid (P < 0.05). During gestation the concentration of skatole and myristic acid were 11. 69 µg/g and 66.24 µg/g respectively. However, during lactation the concentration of these analytes significantly increased by 62 % and 11 % respectively (P < 0.05). A free-choice preference assessment showed that piglets had a preference for feeders sprayed with 5 mL of a mineral oil solution containing skatole (4.5 mg) and myristic acid (9.0 mg) (P < 0.05), but not either molecule alone. The application of skatole and myristic acid to the feeders of weaned pigs statistically reduced piglet aggression by 30 % and increased feeding behavior by 35 % the first 24 h post weaning (P < 0.05). No difference in performance was observed over a 28-d period. Overall, because having access to maternal feces improved piglet performance by 10 %, coprophagy presents as a beneficial behavior to piglets. In addition, skatole and myristic acid might be acting as a multicomponent maternal semiochemical that attracts piglets and has a calming effect at weaning.