University of Saskatchewan Research Archive
Not a member yet
14369 research outputs found
Sort by
The effects of sow grouping practices on production and mixing aggression
No full textAs the Canadian swine industry transitions gestation housing from stalls to groups, it is important to understand the impact of different grouping practices on sow productivity and welfare. When sows are housed in groups, a social hierarchy is established through aggressive behaviour which can negatively impact production. Many producers are implementing dynamic groups and early mixing using precision feeding; however, there is potential for greater aggression and the consequences of this practice are not fully known.
This study compared the effects of three grouping treatments in gestation on sow productivity and aggression. Treatments included: Control (Con): sows housed in stalls for 35 days after insemination, then moved to static groups; Static (Sta): sows mixed into static groups 1-8 days after insemination; and Dynamic (Dyn): sows mixed into dynamic groups 1-8 days after insemination with monthly mixing (8-10 sows removed and replaced). Mixed parity sows and gilts were housed in groups of 25 per pen in three replicates per treatment. Body weight, body condition score and backfat thickness were recorded once at breeding and again when sows were moved to farrowing. Farrowing rate, litter characteristics and piglet birthweights were recorded. On the day of mixing, sow behaviour was video recorded for measurement of reciprocal and one-sided aggression. Skin lesions and lameness were scored before and after mixing, at ~day 63 of gestation, ~day 91 of gestation, and on the day of moving to farrowing. Hair samples were collected at 7- and 12-weeks post-insemination for cortisol analysis. Statistical analysis was performed in SAS 9.4 using mixed effects models and Chi-square analysis.
Grouping practice did not have a significant effect on change in body weight, backfat thickness or body condition during gestation. Farrowing rates for Con, Dyn and Sta treatments were 81%, 88% and 62%, respectively (Chi sq p<0.001). There were no significant treatment differences for litter characteristics. At mixing, Sta sows had a higher frequency of reciprocal fighting in the first half hour (Chi sq p<0.001), than did Con or Dyn sows. However, during the 24 hrs following mixing, sows in the Con treatment received more lesions in total than did Sta or Dyn sows (means ±SEM: Con: 11.71 ±0.46; Dyn: 8.69 ±0.40; Sta: 9.09 ±0.41, p<0.01)). Lesion scores decreased significantly over time in all groups. Throughout gestation, Dyn sows had higher lesions overall and a higher incidence of lameness than either Con or Sta sows (p<0.001 and p=0.046, respectively). Although treatment had no effect on hair cortisol concentrations, parity group had a significant effect on concentrations at both timepoints with young sows having the highest concentration and mid parity sows the lowest (p=0.04, p<0.01, respectively).
In conclusion, Con and Sta sows appeared to be more aggressive at mixing while aggression in Dynamic groups appeared to be moderated due to the smaller number of unfamiliar sows introduced at each mixing event. Dyn sows had more lesions and increased lameness overall during gestation suggesting increased chronic aggression for dynamic sows, although the results were not severe enough to impact farrowing rate or litter quality. In conclusion, dynamic mixing may serve as a viable housing alternative for pork producers provided that the management strategies are implemented to mitigate the effects of ongoing aggression
Identifying new protocol methods in polyploidy research with Cannabis sativa L
No full textThe development and critique of an improved experiment and protocol analysis is critical in terms of this research experiment. With little published research in the development of polyploid cannabis, it was crucial that steps were taken to test and report the methods and protocols provided thus far. The development and discovery that Pisum sativum L. impeded the ploidy analysis of Cannabis sativa L. in flow cytometry when used as an internal standard was recognized. In turn, these findings only reinforced the need to find and test better suited endogenous controls for Cannabis sativa L. samples within flow cytometry analysis. The works of producing a more suited protocol for Cannabis sativa L. flow cytometry we can better understand the effects of possible secondary metabolites between the plants within flow cytometry as well as help pave the way for future Cannabis sativa L. ploidy research
A Double-Roof Chinese Solar Greenhouse Environment Monitoring and Simulation
No full textThe abstract of this item is unavailable due to an embargo
Population Coding of Motion-Sensitive Neurons in the Migratory Locust Locusta migratoria
No full textThe abstract of this item is unavailable due to an embargo
The role of embryonic risk cues on the life history, morphology and behaviour of the wood frog Lithobates sylvaticus
Get PDFPredation is an important selective force that can influence prey life history, morphology, physiology, and behaviour. For prey to accurately mitigate their current predation risk, it is vital that they obtain reliable and updated information from their environment. Chemical information, such as alarm cues and disturbance cues, are known to play an important role in risk assessment for aquatic species and stimulates phenotypic plasticity. Alarm cues are chemicals released by a prey that have been attacked by a predator, while disturbance cues are released by uninjured, distressed prey prior to an attack or during a missed predation event. Both cues are detected during the embryonic and post embryonic stages. Alarm cues can be produced in the embryonic stage and can affect the morphology and hatching time of embryos. However, the way in which alarm cue exposure at this early stage impacts post-embryonic behaviour is unknown. In addition, it is unknown if embryos can produce disturbance cues. Using wood frog (Lithobates sylvaticus) embryos, I explored the existence of embryonic disturbance cues and their effects on hatching time, morphology, post-embryonic behaviour and growth during the larval stage, as well as the effect of embryonic alarm cues. Embryonic disturbance cues and embryonic alarm cues caused delayed hatching, and decreased size of tadpoles. Embryonic disturbance cues also caused a decrease in response to larval alarm cues. Neither cue caused a change in morphology. Wood frog embryos can produce disturbance cues. These cues as well as embryonic alarm cues are used by embryos to assess the risk in their environment and produce a response according to the risk. This study is the first to examine the production of embryonic disturbance cues and their effects, providing data to better understand the ecological implications of disturbance cues during the embryonic stage, and contribute to our understanding of how much prey rely on disturbance cues to assess risk
DESIGN, THERMAL SIMULATION AND ECONOMIC FEASIBILITY ANALYSIS OF A PLANT FACTORY HOUSED IN A UNDERGROUND MINE DRIFT
No full textThe abstract of this item is unavailable due to an embargo
Helical Poly(ferrocenylsilane)s Through Thermal Ring-opening Polymerization of Enantiopure Sila[1]ferrocenophanes
No full textThe abstract of this item is unavailable due to an embargo
Politeness among Iranians: Taarof use in focus
Get PDFThis study focuses on the Iranian exaggerated politeness system called “taarof”. It investigates Iranians’ attitudes toward taarof use as well as some features of taarof perception and production which may be affected by gender, socioeconomic status, and geographic variation. To do so, I recruited a total of 96 research participants (within the age group of 30 to 40 years old) who were grouped by the above variables as follows: a) gender: 48 males and 48 females; b) two educational backgrounds: 48 secondary education and 48 post-secondary education; c) two different urban areas: 48 Isfahan residents and 48 Alborz residents; and d) two occupational categories: 48 skilled and 48 unskilled. As an initial step, a questionnaire survey was employed to obtain quantifiable data on perception of taarof characteristics and on taarof use by the participants. Second, a speech production elicitation technique was used to elicit taarof expressions in quasi-spontaneous prompted dialogues. All the 10-minute conversations were recorded and transcribed for further analysis. The results of the survey part showed that attitudes toward taarof significantly differ by geographical variation and socioeconomic status, however, not by gender. In addition, the analysis of the conversation transcripts displayed significant differences in the frequency of taarof use by province and education, whereas no significant differences were observed by gender and occupation
Autonomic control of heart rate in children with congenital heart disease
Get PDFCongenital heart disease (CHD) is the leading form of birth defects worldwide. Advancements in neonatal management and surgery have led to better outcomes for all types of CHD lesions. Children with CHD may demonstrate autonomic dysfunction indicated by a reduction in heart rate variability (HRV) at rest and delayed heart rate recovery (HRR) post-exercise compared to healthy children. We postulate that children with CHD may not engage in regular physical activity and have a higher body mass index (BMI) compared to healthy children, due to several causes. It is not known whether children with CHD matched with healthy control children on age, BMI, and physical activity will exhibit autonomic dysfunction. HYPOTHESES: We tested three hypotheses: Compared to age, BMI matched healthy controls, and with approximately similar self-reported physical activity levels, (1) children with CHD would have reduced heart rate variability at rest; (2) children with CHD would have slower heart rate recovery kinetics following the six-minute walk test; and (3) there would be a significant correlation between resting heart rate variability and heart rate recovery kinetics. METHODS: Eighteen children with CHD (f/m=7/11) were matched on age, BMI, and approximately similar physical activity (using the Physical Activity Questionnaire for Older Children, PAQ-C) with 18 healthy control children (CTL) (f/m=10/8). Heart rate variability (HRV) was determined following 10-min (minutes) of supine rest using a 5-min surface electrocardiogram (ECG) recorded epoch. Post-exercise HRR kinetics were determined following a 6-min walk test (6MWT) over a 4-min period using telemetry-based HR. Mono-exponential modelling was used to derive the HRR time constant (time to reach 63% change). Analyses included unpaired t-tests for demographics, HRV, 6MWT distance, 6MWT HR, and post-exercise HRR kinetics between the two groups. ANOVA and ANCOVA (with physical activity as the covariate) were used to compare group differences. Factorial ANOVA was used to analyze differences between the groups on exercise HR. Multiple linear regression was used to determine the relationship between 6MWT HR and HRV, 6MWT distance and HRV, and between HRR time constant and HRV. Simple linear regression was used to determine the relationship between 6MWT distance and average 6MWT HR with HRR. Data are presented as mean±SD and P < 0.05 was considered significant. RESULTS: There was no statistically significant difference between children with CHD and CTL on age (12±2 years vs. 11±3 years, P = 0.6245), BMI (19±3 vs. 19±4, P = 0.8456), and physical activity (3.06±0.77 vs. 3.48±0.55, P = 0.0646). On average, children with CHD had a lower resting SDRR (standard deviation of R-R intervals, 62±41 ms vs. 92±24 ms; P = 0.0093), lower 6MWT distance (528±53 m vs. 608±81 m; P = 0.0013), lower average 6MWT HR (120±12 beats/min vs. 138±17 beats/min; P < 0.001), lower end-exercise HR (127±14 beats/min vs. 149±19 beats/min; P < 0.001), lower recovery amplitude (39±14 beats/min vs. 57±15 beats/min, P < 0.001) and higher HRR time constant (33±15 s vs. 24±8 s; P = 0.0334) compared to CTL. When accounting for variance from PAQ-score, there was a difference between the groups on SDRR (P = 0.0331) but no difference between the groups on HRR (P = 0.0809). Heart rate was lower throughout the 6MWT at each minute of exercise in CHD vs. CTL (all P < 0.005). Of all HRV parameters, SDRR had the strongest relationship with 6MWT distance (r = 0.347, P = 0.0382) and HRR time constant (r = - 0.350, P = 0.0365). Inspection of SDRR indicated 7/18 children with CHD had an SDRR above the group mean SDRR in CHD and within or above the SD of the SDRR of CTL. The CHD subgroup with high SDRR reported a higher PAQ-score compared to CHD subgroup with low SDRR (3.50±0.71 vs. 2.78±0.69; P = 0.0485). CONCLUSION: Our findings demonstrate that children with CHD often have a lower HRV at rest, but not in all cases. Children with CHD and relatively high SDRR report higher levels of physical activity compared to their counterparts with relatively lower SDRR. On average, children with CHD display lower HR during exercise, and this coincides with reduced 6MWT distance. The HRR is slower in children with CHD compared to healthy matched CTL which may be related to resting SDRR; however, the slower HRR in children with CHD is more comparable to CTL when accounting for self-reported physical activity. Collectively, these data indicate that cardiac autonomic dysfunction is commonplace in children with CHD and may be influenced by physical activity
Violations of Bayesian Thinking: An Exploration of Potential Causes
Get PDFThis research seeks to determine what factors influence participants to violate Bayes Theorem when they are asked to solve seemingly simple reasoning problems, in which applying Bayes Theorem is an appropriate strategy. There are three primary hypotheses underlying this goal. First, the extent to which information reflects prior beliefs will influence behaviour. Second, that the amount of information will affect behaviour. Third, that the Reasoning Strategy of the participant will affect their behaviour. These hypotheses were addressed in the context of the Base Rate Neglect Task, which requires participants to determine the probability of a randomly selected person from one of two groups. For each problem, participants were given a base rate of the number of people belonging to each group as well as a personality description. The personality descriptions and base rates could suggest to the participant either the same answers or different answers. The Base Rate Neglect Task was used, in part, because it allowed for the manipulation of both the extent to which information reflected prior belief and the quantity of information through the personality descriptions. Overall, the findings from both experiments support the hypothesis that variations in diagnosticity contribute to an increase in Bayes violations. Conversely, neither experiment found support for hypothesis that the amount of information would influence the number of Bayes violations. Finally, only experiment two found support for an increase in Bayes violations that were dependent on Reasoning Strategy