Research Interests:
Abstract Consumers’ interest in specialty eggs appears to be growing in Europe and North America. The objective of this research was to develop logistic regression models that utilise purchaser attributes and demographics to predict the... more
Abstract Consumers’ interest in specialty eggs appears to be growing in Europe and North America. The objective of this research was to develop logistic regression models that utilise purchaser attributes and demographics to predict the probability of a consumer purchasing a specific type of table egg including regular (white and brown), non-caged (free-run, free-range and organic) or nutrient-enhanced eggs. These purchase prediction models, together with the purchasers’ attributes, can be used to assess market opportunities of different egg types specifically in British Columbia (BC). An online survey was used to gather data for the models. A total of 702 completed questionnaires were submitted by BC residents. Selected independent variables included in the logistic regression to develop models for different egg types to predict the probability of a consumer purchasing a specific type of table egg. The variables used in the model accounted for 54% and 49% of variances in the purchase of regular and non-caged eggs, respectively. Research results indicate that consumers of different egg types exhibit a set of unique and statistically significant characteristics and/or demographics. For example, consumers of regular eggs were less educated, older, price sensitive, major chain store buyers, and store flyer users, and had lower awareness about different types of eggs and less concern regarding animal welfare issues. However, most of the non-caged egg consumers were less concerned about price, had higher awareness about different types of table eggs, purchased their eggs from local/organic grocery stores, farm gates or farmers markets, and they were more concerned about care and feeding of hens compared to consumers of other eggs types.
Research Interests:
As part of the Canadian Wildlife Service monitoring of great blue herons in British Columbia, eggs were collected from three colonies with low, intermediate, and high levels of PCDD and PCDF contamination: Nicomekl, Vancouver, and... more
As part of the Canadian Wildlife Service monitoring of great blue herons in British Columbia, eggs were collected from three colonies with low, intermediate, and high levels of PCDD and PCDF contamination: Nicomekl, Vancouver, and Crofton, respectively. One egg from each nest was used for chemical analysis by GC-MS; the others were hatched. Liver microsomes were prepared from the heron chicks and used for determination of cytochrome P-450-dependent activities. No erythromycin N-demethylase activity was found in any sample. Ethoxyresorufin O-dealkylase activity in the Nicomekl group was similar to that in pigeons, a control altricial species. The ethoxyresorufin activity in the herons from the Crofton colony was 2.6-fold higher than in the Nicomekl group. The Vancouver colony was intermediate. No difference among the three heron colonies was found in pentoxyresorufin O-dealkylase activity, although levels were 20-33 times that in the pigeon. Chemical analysis was carried out on paire...
Research Interests: Toxicology, Biology, Medicine, Environmental Sciences, Liver, and 14 moreBirds, Animals, Oxidoreductases, Chemical Analysis, British Columbia, CHEMICAL SCIENCES, Multiple regression analysis, Heron, Correlation coefficient, Pigeon, Dioxins, Enzyme Induction, Medical and Health Sciences, and mixed function oxidase (MFO)
Research Interests:
A multiphasic function that considers egg production of individual hens to result from more than one phase was used to describe egg production for Japanese quail. Each phase is determined by number of eggs within a clutch, including... more
A multiphasic function that considers egg production of individual hens to result from more than one phase was used to describe egg production for Japanese quail. Each phase is determined by number of eggs within a clutch, including internally laid eggs, and pause between clutches. Cumulative egg production was fitted by using a function (Koops and Grossman, 1992) expressing time in terms of cumulative egg number. Data from nine hens over a 31-day period were analyzed to estimate parameters for lag and delay. The data were preadjusted for internal laying. Lag ranged from -1.14 to .19 h. Unlike chickens, there was no clear relationship between lag and average clutch length in Japanese quail. Average delay was about 21.6 h and seemed to be longer than that in the chicken. Furthermore, the residual standard error for delay was higher in Japanese quail than in the chicken.
Research Interests:
Research Interests:
To estimate, in male quail susceptible to atherosclerotic plaque formation (SUS) fed a regular diet and an atherogenic diet, the genetic and phenotypic parameters associated with antioxidant enzymes and atherogenesis. Genetic parameters... more
To estimate, in male quail susceptible to atherosclerotic plaque formation (SUS) fed a regular diet and an atherogenic diet, the genetic and phenotypic parameters associated with antioxidant enzymes and atherogenesis. Genetic parameters were estimated from variance components of the analysis of variance on 70 males from 13 full-sib families. Under the regular diet, seven of 35 males developed mild atherosclerosis. Heritability was zero for atherosclerotic plaque score and plasma cholesterol level. Plaque score was highly correlated to plasma triglyceride level (rp = 0.96) and liver fattiness (rp = 0.97), but only moderately to plasma cholesterol level (rp = 0.39). With the high cholesterol diet, plasma cholesterol level increased sixfold and became heritable (h2 = 0.4). Many males developed severe atherosclerosis. Plaque score became associated more with plasma and aortic cholesterol levels (rp = 0.56) and 0.76, respectively) than with plasma triglyceride level (rp = 0.54). Aortic g...
Research Interests:
Research Interests:
The overall objective was to develop an in vitro test to predict fertility of bulls in the field. We investigated the bull effect on in vitro embryo production, zona binding and acrosome reaction, and the correlation of this effect to... more
The overall objective was to develop an in vitro test to predict fertility of bulls in the field. We investigated the bull effect on in vitro embryo production, zona binding and acrosome reaction, and the correlation of this effect to field fertility meas ured by 60–90 d non-return rate. Frozen semen from three separate ejaculates of eight unrelated young bulls, obtained from an artificial insemination (AI) center, was used. On thawing, ejaculates from each bull were pooled, motile sperm were selected and (a) subjected to immunofluorescent assay at 0 and 4 h of incubation in capacitation medium to assess acrosome status, (b) used in an in vitro fertilization assay system to assess cleavage and blastocyst production rates, and (c) sperm-zona binding assay was carried out to determine the number of sperm bound to the zona pellucida of mature oocytes. Percentage of pre-freeze motile sperm (PrFM) and non-return rate data were obtained from the AI center. PrFM, percentage of acrosome rea...
Research Interests:
Research Interests:
Records of 1,530 Japanese quail were used to estimate heritabilities and genetic correlations based on a derivative-free restricted maximum likelihood (REML) method with an animal model and ANOVA. The animal model included fixed effects... more
Records of 1,530 Japanese quail were used to estimate heritabilities and genetic correlations based on a derivative-free restricted maximum likelihood (REML) method with an animal model and ANOVA. The animal model included fixed effects of hatch and sex, random effects of additive genetic value of the bird, and common environmental effect of the dam. Heritabilities estimated from REML for body weights at hatch, 7, 14, 21, and 28 d of age were .38, .12, .31, .12, and .44, respectively. Heritabilities estimates from the sire component of variance for the same traits were .57, .08, .28, .15, and .47. These values indicate that genetic progress can be made by selecting for either 14-d or 28-d body weight. Genetic correlation (REML) of .76 between body weights at 14 and 28 d of age indicates the possibility of improving body weight at 28 d of age by selecting for body weight at 14 d of age.
Research Interests:
The effects of divergent growth selection for 18 generations on semen characteristics, fertility and hatchability were investigated. Males from the low weight line produced semen with a significantly (P less than or equal to 0.05) higher... more
The effects of divergent growth selection for 18 generations on semen characteristics, fertility and hatchability were investigated. Males from the low weight line produced semen with a significantly (P less than or equal to 0.05) higher sperm concentration and a highly significantly (P less than or equal to 0.01) lower methylene blue reduction time than the males from the high line. Differences between lines for semen volume, sperm motility, percent of live sperm, fertility and hatchability were not statistically significant.
Research Interests:
Productive coastal and estuarine habitats can be degraded by contaminants including persistent organic pollutants (POPs) such as PCBs, dioxins, and organochlorine insecticides to the extent of official designation as contaminated sites.... more
Productive coastal and estuarine habitats can be degraded by contaminants including persistent organic pollutants (POPs) such as PCBs, dioxins, and organochlorine insecticides to the extent of official designation as contaminated sites. Top-predatory wildlife may continue to use such sites as the habitat often appears suitable, and thus bioaccumulate POPs and other contaminants with potential consequences on their health and fitness. Victoria and Esquimalt harbours are located on southern Vancouver Island, British Columbia (BC) and are federally designated contaminated sites due mainly to past heavy industrial activities, such as from shipyards and sawmills. We collected scat samples from river otters (Lontra canadensis) throughout an annual cycle, and combined chemical analysis with DNA genotyping to examine whether the harbour areas constituted a contaminant-induced ecological trap for otters. We confirmed spatial habitat use by radio telemetry of a subsample of otters. Fifteen pe...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Canada, Birds, Animals, Oxidoreductases, Polychlorinated Biphenyls, and 3 moreEggs, Body Weight, and Dioxins
Research Interests:
Research Interests: Evolutionary Biology, Genetics, Zoology, RNA, DNA, and 5 moreAnimals, Experimental, Palate, Protein Biosynthesis, and fluorouracil
Research Interests:
Research Interests: Agriculture, Population Dynamics, Biological Sciences, Environmental Sciences, Pesticide, and 15 morePesticides, Female, Animals, Male, British Columbia, CHEMICAL SCIENCES, Eggs, Oxygen, Larva, Intensive farming, Environmental Toxicology and Chemistry, Native Species, Ambystoma, Environmental, and Congenital abnormalities
Research Interests:
The pineal gland plays an important role in seasonal adaptation including variation in energy requirement. Animals exhibiting seasonal changes in their energy expenditure would be benefited if their cardiac and pulmonary systems respond... more
The pineal gland plays an important role in seasonal adaptation including variation in energy requirement. Animals exhibiting seasonal changes in their energy expenditure would be benefited if their cardiac and pulmonary systems respond to the pineal photoperiodic signal, melatonin, appropriately. Thus, we would like to hypothesize that melatonin receptors are present in the heart and lung. Using a specific labeled melatonin agonist, 2-[125I]iodomelatonin, binding sites were demonstrated in the lung and heart of birds and other animals. In the chicken lung, there were high affinity (equilibrium dissociation constant, Kd = 9.11 +/- 0.73 pmol/l) and low density (maximum number of binding sites, Bmax = 1.29 +/- 0.16 fmol/mg protein) 2-[125I]iodomelatonin binding sites that were highly specific to melatonin. Similar binding with lower density was demonstrated in the quail and frog lungs. In the duck heart, specific 2-[125I]iodomelatonin binding sites with a Kd of 30.5 +/- 3.5 pmol/l and...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Carotenoids, Apoptosis, Female, Animals, Male, and 15 moreCell Death, Light, Dietary Supplements, Japanese Quail, Age related macular degeneration, Beta Carotene, Lutein, Time Factors, Macular pigment, Age Factors, Stepwise Regression, Retinal Diseases, Neurosciences, Medical biochemistry and metabolomics, and Macula lutea
Research Interests: Environmental Monitoring, Raptors, Biological Sciences, Environmental Sciences, Liver, and 15 moreFemale, Animals, Regression Analysis, Polychlorinated Biphenyls, Gas Chromatography, British Columbia, Polychlorinated Biphenyl, CHEMICAL SCIENCES, Fresh water, Oregon, Environmental Toxicology and Chemistry, Environmental, Kraft Pulping, ovum, and yolk sac
SummaryThe diet patterns and trophic relationships are poorly understood for most tropical owl species. We used stable isotopes of carbon (δ13C) and nitrogen (δ15N) in 24 feather samples of the rare, endemic, and ‘Near Threatened’ Bearded... more
SummaryThe diet patterns and trophic relationships are poorly understood for most tropical owl species. We used stable isotopes of carbon (δ13C) and nitrogen (δ15N) in 24 feather samples of the rare, endemic, and ‘Near Threatened’ Bearded Screech-owl Megascops barbarus to determine the trophic level of their prey and evaluate whether diet patterns vary (1) among individuals, (2) spatially along the species's range in the highlands of Chiapas, Mexico, and (3) temporally during the short- and long-term. Our results indicated that there was diet variation among individuals during the period of feather growth and there was a high positive correlation between stable isotopes in body and rectrices. The stable isotopes showed significant temporal differences in δ15N signature values, but not in δ13C values, with no obviously interpretable temporal pattern. Spatially, values of δ13C and δ15N did not vary across all nine sampled locations. The observed lower δ13C values suggested that th...
Research Interests:
Research Interests:
Research Interests:
Research Interests: Poultry Science, Animal Production, Mutation, Female, Animals, and 4 moreMale, Feathers, Food Sciences, and Quail
Research Interests:
Research Interests:
Data were collected on reproductive, health and production events in 45 dairy herds in southwestern and eastern Ontario, Canada, from July 1990 to July 1993. Mean and median days in milk at first estrus, at first service, and at... more
Data were collected on reproductive, health and production events in 45 dairy herds in southwestern and eastern Ontario, Canada, from July 1990 to July 1993. Mean and median days in milk at first estrus, at first service, and at conception were 85.1 and 83.9, 94.0 and 88.9, and 126.3 and 115.5 d, respectively. The mean estrus detection rate was 48.3%, with a minimum of 28.4% and a maximum of 64.2%. The mean overall conception rate was 46.7%, with a minimum of 29.8% and a maximum of 70.7%. The most commonly used used therapeutic agents were GnRH (11.5% lactational incidence risk) and PG (13.1% lactational incidence risk). Estrus management accounted for the largest portion of PG use in the herds studied (69.4%). Results of a two sample t-test indicated no significant difference in reproductive performance among herds housed in free-stall compared with those housed in tie-stall barns. Multivariate linear regression models of 3 reproductive performance measures indicated that cows with ovarian cysts and/or increased peak milk production had significantly longer calving-to-first estrus and calving-to-conception intervals as well as lower conception rates than average producing cows without cysts. Cows with metritis were found to have significantly shorter calving-to-conception intervals but no detectable difference in conception rate or calving-to-first estrus interval than their herdmates. As lactation number increased reproductive performance improved. Cows that were observed in estrus earlier conceived earlier. Animals receiving uterine infusions had significantly longer calving-to-conception intervals and lower conception rates than their herdmates. There was no detectable difference in reproductive performance for cows treated with GnRH or PG compared with the nontreated cows. An increased estrus detection rate was associated with shorter calving-to-conception intervals and lower conception rates. Based on the range of performance in the study herds, the factors with the greatest potential influence on calving-to-conception interval in the average herd were the estrus detection rate and conception rate.
Research Interests: Mate Choice, Reproduction, Aging, Fertility, Lactation, and 18 moreLinear models, Theriogenology, Biological Sciences, Pregnancy, Female, Animals, Male, Ontario, tESTIS, Cattle, Ducks, Time Factors, Mallard, Gonadotropin Releasing Hormone, Oviposition, Captive Wild Animals, Ovarian cysts, and Dairying
Research Interests:
Research Interests:
The distribution of the Cascade mantled ground squirrel, Spermophilus saturatus, in British Columbia. MC Leung, KM Cheng Canadian field-naturalist. Ottawa ON 111:33, 365-375, 6/1997. The Cascade Mantled Ground Squirrel ...
Research Interests:
The distribution of the Cascade mantled ground squirrel, Spermophilus saturatus, in British Columbia. MC Leung, KM Cheng Canadian field-naturalist. Ottawa ON 111:33, 365-375, 6/1997. The Cascade Mantled Ground Squirrel ...
Research Interests:
1. Exp Eye Res. 1999 Nov;69(5):579-81. rd and rc chickens carry the same GC1 null allele (GUCY1*). Semple-Rowland SL, Cheng KM. PMID: 10548480 [PubMed - indexed for MEDLINE]. Publication Types: Letter; Research ...
Research Interests:
1. Exp Eye Res. 1999 Nov;69(5):579-81. rd and rc chickens carry the same GC1 null allele (GUCY1*). Semple-Rowland SL, Cheng KM. PMID: 10548480 [PubMed - indexed for MEDLINE]. Publication Types: Letter; Research ...