The objective of this study was to evaluate the relationship between hair coat shedding ability, apparent forage digestibility, and mineral status in Angus cattle. Fecal samples were collected on fall calving Angus cows for one week in March, May, and July from 2019-2022. Liver and plasma samples were collected in March and July each year. Fecal samples were analyzed for DM, ash, NDF, and ADF while liver and plasma were analyzed for mineral concentration. Data were analyzed using MIXED procedure of SAS with significance declared at P0.05. Interactions were detected for DM, NDF, ADF, and liver Fe concentration. The model included MFS, month, and MFS by month interaction for each response variable. Interpretation of results showed no clear trends or associations between hair coat shedding ability, apparent forage digestibility, and mineral status, but further investigation is needed to understand cow performance due to relationships between genes and environment.

In the U.S., soybean mosaic virus (SMV) is classified into seven strain groups, designated G1 to G7, based on their different responses on resistant soybean [Glycine max (L.) Merr.] cultivars. These responses are: symptomless or resistant (R), necrotic (N), and mosaic or susceptible (S). The gene-for-gene model has been proposed for SMV-soybean interactions. In the majority of cultivars, a single dominant gene, Rsv1, confers both the R and N responses. In the first part of this study, the coat protein (CP) genes of two SMV strains, G1 and G6 were isolated, cloned, and sequenced. Gene isolation was done by reverse transcription-polymerase chain reaction (RT-PCR) on partially purified virus preparation without prior RNA extraction. Amplified products were blunt-end ligated into pNoTA/T7 vector and transformed into competent cells. Sequencing was performed in both directions on heat-denatured double-stranded plasmids. The predicted 265 amino acid sequence of the CP of G1 and G6 strains were 98.9% identical, with only two amino acid differences. Correlating the CP sequences of G1, G2, G6, and G7, with their virulence on resistant soybean cultivars indicated that the CP is not likely to be the R- and/or N-determinant in the SMV-soybean system. The second part of the study involved studying the pathogenesis of G1, G6, and G7 strains on inoculated leaves of R, N, and S soybean cultivars by leaf imprint immunoassay. Results indicated four types of reactions: i) susceptible, showing unrestricted replication and spread; ii) immune, where no virus was detected; iii) systemic spread, showing unrestricted replication but limited spread along the veins; and iv) restricted replication and spread, where infection was restricted to few foci along the veins. Results of this study indicated that Rsv1-mediated resistance is a multicomponent type of resistance that involves both inhibition of virus replication as well as cell-to-cell movement. The third part of the study aimed at investigating Rsv1-mediated resistance at the cellular level. For this purpose, an SMV-soybean protoplast system was developed. Protoplast isolation was based on a combined cellulase-pectolyase Y-23 digestion and metrizamide-sorbitol gradient purification protocol. Virus inoculation of protoplasts was facilitated by either polyethelene glycol (PEG) or poly-L-ornithine (PLO), and method of detection was by Western blotting using antiserum to whole virus. Inoculation by PEG was successful, but results were irreproducible because of the adverse effect of PEG on protoplast viability. Inoculation by PLO was inconclusive because of the high background from residual inoculum. Additional research is needed before a protoplast system can be used to study the mechanism of Rsv1 resistance to SMV at the cellular level. / Ph. D.

Asphalt tack coats are applied during pavement construction to ensure bond between pavement layers, thus providing a more durable pavement. A prototype tack coat evaluation device (TCED) was developed to evaluate the tensile and torque-shear strength of tack coat materials. Three emulsions (SS-1, CSS-1, and CRS-2) and one asphalt binder (PG 67-22), commonly used as tack coats, were evaluated using the TCED at various application temperatures, application rates, dilutions, and set times. A laboratory bond interface strength device (LBISD) was developed to assess interface shear strength of laboratory-prepared specimens. Mass loss testing was performed to evaluate moisture evaporation and visual breaking properties of emulsions. Study results indicate application rate, tack coat, and emulsion set time significantly affect TCED strength. Application rate also affected evaporation rate of emulsions.

The domestication of animals is a process of great interest to many scientific fields, including genetics. Differences in coat colour between wild and domesticated animals have been of scientific interest for a long time. Coat colours are easily recognizable phenotypes and so have been studied since the dawn of modern genetics. Many phenotypes that are similar across species have the same genetic basis, but there are numerous exceptions. Similar phenotypes within a species can also have different genetic backgrounds. The progressive advances in genetic research methodology have given new insights into both the molecular basis for coat colours and the history of domestication over the last decades. The variation in coat colours seen today is believed to be caused mainly by human selection. Similarities in morphological changes between different species during domestication, including colour phenotypes such as white spotting, have long been noted. This is known as the domestication syndrome and two major hypotheses for this have been suggested: the neural crest hypothesis and the thyroid hormone hypothesis. This thesis gives an overview of the current knowledge about the genetic basis of coat colours in mammals, the genetic aspects of domestication of animals, and how the two are related.

Three interrelated genes postulated to affect economically important traits related to growth and/or carcass quality of beef cattle were chosen to characterize and perform association analyses for this study. Melanocortin 1 receptor (MC1R), melanocortin 4 receptor (MC4R) and agouti related protein (AGRP) play an integral role in the appetite pathway and in fat deposition.<p> We genotyped 328 crossbred steers of various coat colours that were purchased at weaning and fed until slaughter for the previously published alleles ED, E+ and e. The E+ allele was present at five percent in this population and therefore was not included in further analysis. Black cattle of ED/ED or ED/e genotype had increased backfat (P<0.05) and required significantly fewer days (15-25) (P<0.01) on feed to reach a target fat level for slaughter compared to the red cattle. Red cattle of e/e genotype were found to have significantly larger longissimus dorsi (l. dorsi) area, shipping weight and hot carcass weight. Subsequent analysis revealed that the differences were comparable whether black versus red coat colour or MC1R genotype was used as the criteria for the group of cattle.<p> MC4R sequence was obtained from 20 random crossbred steers. In addition to several previously published polymorphisms, a novel Ser330Asn polymorphism was detected. A population of 382 crossbred Canadian steers and 985 crossbred American steers was genotyped for this Ser330Asn polymorphism. A minor allele frequency of 0.01 was observed in the Canadian and 0.02 in the American steer populations. No homozygous g.989AA cattle were detected. In the Canadian population, heterozygous steers had increased grade fat (P=0.036) and decreased lean meat yield (P=0.032). Similarly in the American population, steers of the g.989GA genotype had increased backfat (P=0.031) and less desirable yield grades (P=0.022,) but also lower ribeye area measurements (P=0.031). These results suggest that genotyping for the Ser330Asn polymorphism may lead to increased quality of carcasses either through lean meat production or backfat measurements, depending on the goal of the beef operation.<p> Sequence data obtained from 38 Bos taurus beef cattle, 4 Holsteins and 4 Bos indicus cattle revealed six polymorphisms in the AGRP gene. No polymorphisms that altered amino acids were detected in Bos taurus cattle. Genotyping of 382 crossbred beef steers was performed for two polymorphisms, an intronic deletion (g.439_440delTC) and a base pair substitution in exon 4 that did not alter an amino acid (g.715G>A). An ANOVA analysis, using PROC Mixed, was performed for both polymorphisms on several growth and carcass traits. No significant differences were observed.<p> Polymorphisms in MC1R and MC4R could be used as genetic tests which may be beneficial for beef producers in North America. The significant differences observed in this study in relation to cattle growth and fat deposition would represent savings for producers when used for sorting feedlot cattle or in selection of breeding cattle.

Three interrelated genes postulated to affect economically important traits related to growth and/or carcass quality of beef cattle were chosen to characterize and perform association analyses for this study. Melanocortin 1 receptor (MC1R), melanocortin 4 receptor (MC4R) and agouti related protein (AGRP) play an integral role in the appetite pathway and in fat deposition.<p> We genotyped 328 crossbred steers of various coat colours that were purchased at weaning and fed until slaughter for the previously published alleles ED, E+ and e. The E+ allele was present at five percent in this population and therefore was not included in further analysis. Black cattle of ED/ED or ED/e genotype had increased backfat (P<0.05) and required significantly fewer days (15-25) (P<0.01) on feed to reach a target fat level for slaughter compared to the red cattle. Red cattle of e/e genotype were found to have significantly larger longissimus dorsi (l. dorsi) area, shipping weight and hot carcass weight. Subsequent analysis revealed that the differences were comparable whether black versus red coat colour or MC1R genotype was used as the criteria for the group of cattle.<p> MC4R sequence was obtained from 20 random crossbred steers. In addition to several previously published polymorphisms, a novel Ser330Asn polymorphism was detected. A population of 382 crossbred Canadian steers and 985 crossbred American steers was genotyped for this Ser330Asn polymorphism. A minor allele frequency of 0.01 was observed in the Canadian and 0.02 in the American steer populations. No homozygous g.989AA cattle were detected. In the Canadian population, heterozygous steers had increased grade fat (P=0.036) and decreased lean meat yield (P=0.032). Similarly in the American population, steers of the g.989GA genotype had increased backfat (P=0.031) and less desirable yield grades (P=0.022,) but also lower ribeye area measurements (P=0.031). These results suggest that genotyping for the Ser330Asn polymorphism may lead to increased quality of carcasses either through lean meat production or backfat measurements, depending on the goal of the beef operation.<p> Sequence data obtained from 38 Bos taurus beef cattle, 4 Holsteins and 4 Bos indicus cattle revealed six polymorphisms in the AGRP gene. No polymorphisms that altered amino acids were detected in Bos taurus cattle. Genotyping of 382 crossbred beef steers was performed for two polymorphisms, an intronic deletion (g.439_440delTC) and a base pair substitution in exon 4 that did not alter an amino acid (g.715G>A). An ANOVA analysis, using PROC Mixed, was performed for both polymorphisms on several growth and carcass traits. No significant differences were observed.<p> Polymorphisms in MC1R and MC4R could be used as genetic tests which may be beneficial for beef producers in North America. The significant differences observed in this study in relation to cattle growth and fat deposition would represent savings for producers when used for sorting feedlot cattle or in selection of breeding cattle.

The objective of this work is to enhance the understanding of the delay observed in the early stages of E-coat deposition. E-coat deposition has been widely used by industries such as the automotive industry to form the primary protective coating against corrosion. Currently, models that are used to find the best conditions under which the desired coating coverage for the entire auto body can be achieved do not accurately predict the coating coverage in recessed areas. The accuracy of large-scale models can be improved by enhancing our understanding of the mechanisms responsible for the observed delay. To accomplish this, experiments are performed to define the processes that control deposition initiation and then a model is developed to describe those processes. Simulation results are compared with experimental measurements for a range of conditions to assess the validity of the results. The delay before the onset of deposition is influenced by the type of substrate and properties of the E-coat solution. The impact of the substrate type on the onset of deposition was experimentally investigated. The results of experiments indicated that surface characteristics such as adhesion of bubbles to the surface and the formation of an initial coating increase the local current density on the surface. Investigations of the morphology of the initial coating on different types of substrates indicated that deposition began at areas where the local current density was higher. Increasing the local current density due to the adhesion of bubbles to the surface resulted in a 40% reduction in the time required for the onset of deposition on galvanized steel compared to bare steel. The processes in the solution adjacent to the surface were also investigated to understand the mechanisms responsible for the onset of deposition. Convection was used as a tool to determine the impact of the accumulation of hydroxide ions on the onset of deposition. The results of rotating disk electrode (RDE) experiments showed that the observed delay before deposition was not due to the time required for accumulation of hydroxide ions at the surface. The results of additional experiments showed that the accumulation of micelles was critical to the deposit initiation. The impact of micelle accumulation on the deposit initiation was further explored by developing a mathematical model of the physical processes in the solution adjacent to the surface. The model was evaluated at different conditions and was found to agree with experimental results at different current densities and bulk micelle concentrations. The model and the experimental results from this study help to explain the observed delay in the early stages of E-coat deposition and provide a basis for improving large-scale simulation of E-coat deposition.

Published Article / A study was conducted to determine the differences between four breeds in respect of coat score, hide-thickness, tick burden and body condition score. The study was comprised of 40 heifers - 10 of each breed, namely Afrikaner, Braford, Charolais and Drakensberger. A subjective system of coat scoring, ranging from extremely short to very woolly, was used. Body condition score was measured subjectively, with 1 being emaciated and 9 being obese. Hide-thickness (in mm) and tick count were also determined. Between August 2007 and early March 2008, measurements were carried out on the same 10 animals of each breed, with highly significant differences in body condition score, hide-thickness and tick count being observed between the breeds in all instances. Coat scores differed significantly between breeds in the earlier and latter stages of the study becoming less significant midway through. A significant difference in body condition score within breeds was also found, while hide-thickness did not differ significantly within breeds.

Cortisol is a stress hormone which is released from the adrenals in the Hypothalamic-Pituitary-Adrenal (HPA) axis and plays a major role in animal stress response. Cortisol is used as a stress marker and can be sampled using different methods. A good non-invasive method and a good measure of chronic stress is to measure cortisol through hair. Cortisol is stored in hair for months and therefore reflects chronic stress. The aim of this study was to investigate if cortisol concentration differs depending on coat color. Hair samples from 20 black and white Border collie dogs was analysed and used in this study. Cortisol was extracted with methanol and analysed with ELISA. The results showed no significant difference between black and white coat color within the population while there were individual differences. The results also showed that the sexes do not affect the cortisol concentration. In summary, coat color (black and white) has an effect on cortisol concentration which means that the factor color does need to be taken into account when measuring cortisol through hair.

Although dark coat color in dogs has been theorized as a risk factor for thermal stress, there is little evidence in the scientific literature to support that position. We utilized 16 non-conditioned Labradors (8 black and 8 yellow) in a three-phase test to examine effects of coat color on thermal status of the dog. Rectal, gastrointestinal (GI), surface temperature, and respiration rates measured in breaths per minute (bpm), were collected prior to (Baseline – phase 1) and immediately after a controlled 30-minute walk in an open air environment on a sunny day (Sunlight – phase 2). Follow up measurements were taken 15 minutes after walking (Cool down – phase 3) to determine post-exposure return to baseline. No effect of coat color was measured for rectal, gastrointestinal, surface temperature, or respiration (P > 0.05) in dogs following their 30-minute walk. Temperatures increased similarly across both coat colors (rectal 1.88 °C and 1.83 °C; GI 1.89 °C and 1.94 °C) for black and yellow dogs respectively during the sunlight phase (P > 0.05). All temperatures and respiration rates decreased similarly across coat colors for rectal (0.9°C and 1.0 °C) GI (1.5 °C and 1.3°C) for black and yellow dogs respectively (P>0.05). Similarly, sex did not impact thermal status across rectal, gastrointestinal, surface temperature or respiration rates measured (P > 0.05). These data contradict the commonly held theory that dogs with darker coat color may experience a greater thermal change when compared to dogs with a lighter coat color exposed to direct sunlight.