The objective of this research was to determine differences in carcass evaluation, yield, and meat quality from representative fresh domestic (FSD), frozen domestic (FZD), and frozen imported Australian (FIA) goat carcass sides (n=30 from each source). The U.S. carcasses were split into sides and the right side frozen and stored for 6 weeks. Left sides were fabricated into standardized primal cuts. After frozen storage, right sides and FIA carcasses were thawed for 3 days at 4°C. Three experiments were conducted on the carcass traits and meat yields, quality differences in leg cut, and differences in loin and racks across freezing and packaging treatments. Domestic carcasses were heavier (P<0.05) with more (P<0.05) external fat, but carcass conformation and lean flank color were not different than imported Australian goat carcasses. Australian carcasses had less waste and higher trimmed primal loin, rack, leg, shank, and shoulder yields as % of carcass weight than domestic sides. Freezing and thawing changed the percentages of cuts, but FIA carcasses had higher (P<0.05) yields of lean trimmed primal cuts and FIA legs had higher (P<0.05) drip, cook losses, and water binding, but lower (P<0.05) color values than the FZD legs or FSD legs. With paired t-tests, FZD legs had higher (P<0.05) drip and cook losses and lower (P<0.05) color values than FSD legs. FZD and FIA chops had higher (P<0.05) drip and cook losses than FSD. Freezing lowered (P<0.05) color values of chops, however, packaging with 0.5% CO increased (P<0.05) a* and chroma values of frozen meat over that of fresh goat meat before packaging. Vacuum packaging of goat chops increased (P<0.05) drip and chops in overwrap packaging had the lowest (P<0.05) color values. Packaging did not (P>0.05) affect Warner-Bratzler shear values. FSD chops had higher (P<0.05) shear force values than FZD, which were higher than FIA. Loin chops had greater (P<0.05) drip and cook losses than rib chops. Rib chops were found to have higher (P<0.05) color values both pre and post package and lower (P<0.05) shear force values when compared to loin chops.

One of the most significant threats to the well-being and performance of grazing livestock are gastrointestinal nematode (GIN) parasitic infections. Allowing a large GIN burden to manifest can cause a significant cost in terms of productivity in grazing cattle. Beef producers commonly rely greatly on the efficacy of broad-spectrum anthelmintics, to not only kill resident worms but to also prevent the establishment of ingested infective stage larvae (L3) for a period following treatment. Eprinomectin (LONGRANGE®, E-LR) is the first extended-release injectable cattle dewormer that claims to provide cattle producers season-long persistent parasite control for 100 to 150 d in a single dose, dependent on parasite species. This in turn, improves nutritional efficiency. The purpose of this study is to evaluate the efficacy of E-LR for controlling long-term GIN infections in nursing calves. E-LR was compared to the traditional anthelmintic fenbendazole (Panacur®, F-P). Four groups of nursing calves (with their dams) grazed separate pastures and pastures were rotated after each sampling date to ensure equal parasitic pasture exposure. Two groups were treated with E-LR and two groups were treated with F-P. Calves were weighed at 28 d intervals and fecal samples were collected on d 0, 14, 28, 56, 84, and 112. Results indicated E-LR was effective in providing long term parasite control. There was no significant (p < 0.05) difference in the FEC between F-P and E-LR treated animals on d 14, showing that both were efficient at initially killing GIN. Significant differences in FEC between treatments started to show by d 56. On d 56, there was an increase in FEC in calves treated with F-P which continued to increase throughout the rest of the study. The E-LR treated animals had only slightly increased FEC for the rest of the study which indicated prolonged GIN control.

Vitrification is the latest technique used in cryopreservation, the ability to utilize this method with oocytes and embryos has become a valuable system. Vitrification has been successful with bovine embryos and oocytes but is far from optimal. Following cryopreservation storage discarding embryos can cause ethical issues, and mature oocytes have fragile organelles that can be detrimentally affected by ice crystal formation during freezing. Immature oocytes have not formed some of these temperature sensitive microfilaments and can circumvent these detrimental effects. The common intracellular cryoprotective agents are dimethyl sulfoxide, glycerol and ethylene glycol. Different combination of these agents have been reported for vitrification of oocytes. The overall objective of this experiment was to determine if immature and mature cumulus cell complexes vitrified in solutions of dimethyl sulfoxide or glycerol in combination with ethylene glycol would be competent to produce pronuclei following thawing and in vitro fertilization. Two experiments evaluated two cryoprotectant solutions and their ability to fertilize bovine cumulus cell complexed oocytes (n=400). The first study used DMSO and glycerol containing vitrification solution with immature bovine oocytes (n=200) followed by IVM and IVF with an end point of pronuclei formation to indicate fertilization. The second used DMSO and glycerol containing vitrification solutions with mature bovine oocytes (n=200) followed by IVF. We found that vitrifying immature oocytes with DMSO or Glycerol containing solutions prior to IVF resulted in higher fertilization for DMSO P<.01. Vitrifying mature oocytes with DMSO or glycerol containing also resulted in higher fertilization for DMSO solution P<.05. These results suggest that DMSO may be the more appropriate choice when used in combination with ethylene glycol for vitrification of immature and mature oocytes.

Twenty-four male Holstein calves (BW = 38.78 ± 7.26 Kg) were used to evaluate the effects of commercially available or farm mixed starter on animal performance, blood metabolites, and rumen health. Calves were randomly assigned to one of two treatments which included: commercial calf starter (minimum 20% CP; CCS) and starter of similar nutrient content but hand mixed on farm (FMS). Calves were offered treatments ad libitum on days 4 through 84. Milk replacer (MR) was offered beginning on day 4. On day 42, MR was reduced to once daily to decrease intake by 50%. On day 49 calves were weaned but remained in hutches for the remainder of the 84 d trial. Body weight (BW), hip height, withers height, hip width, and body length were recorded weekly, and grain and milk replacer intakes were measured twice daily. Rumen fluid and blood samples were collected every two weeks beginning on week 2 for analysis of ruminal pH, ammonia (NH3), volatile fatty acids (VFA), plasma urea nitrogen (PUN), plasma glucose, and â-hydroxybutyrate (BHBA). There was a treatment by week interaction (P < 0.05) for BW, starter intake and PUN. Postweaning BW was greater (P < 0.05) for calves fed FMS. Calves fed FMS had higher (P < 0.05) overall ADG. However, there were no differences (P > 0.05) on ADG before weaning. There were no treatment effects (P > 0.05) on structural growth variables, feed efficiency, and fecal scores. Calves fed FMS had greater (P < 0.05) starter intake. There were no treatment effects (P > 0.05) on total VFA concentrations, VFA molar percentages, glucose, and BHBA. Ruminal pH was higher (P < 0.05) for calves fed FMS while ruminal NH3 concentrations were greater (P = 0.03) for calves fed CCS. Calves fed CCS had greater (P < 0.05) PUN concentrations. These data suggest that farm mixed diets can equal commercial calf diets for general performance and rumen development when calf starter meets all the nutrient necessary for normal growth and is properly mixed.

Feeding laying hens or broiler breeder hens organic sources of trace minerals can improve egg quality, especially as related to shell quality. The objectives of this research were to evaluate the effect of increasing laying hen dietary zinc (Zn) levels on the content of Zn and other minerals in eggs (boron (Bo), iron (Fe), and calcium (Ca)), and to evaluate the effect of feeding increasing Zn, manganese (Mn) and copper (Cu) levels from inorganic (ITM) and organic (OTM) sources on egg quality and yolk content of Zn, Mn, and Cu. In the first experiment, a total of 64 (48 weeks of age) commercial hens (Hy-Line W-36) were allotted to one of four treatments diets on day 0. There were four replicates with four hens per replicate. The dietary treatments were: 1) corn-soybean meal (C-SBM) with no added Zn (25 mg/kg total Zn from feeding ingredients), 2) C-SBM with 50 mg/kg added Zn, 3) C-SBM with 100 mg/kg added Zn, and 4) C-SBM with 150 added mg/kg Zn. The inorganic source of Zn was ZnSO4. The trial lasted 30 days. In the second trial, 600 Hy-Line W-36 hens at 26 weeks of age were used. Hens were allotted to one of five treatment diets on day 0 of the trial. A total of 10 replicates with 12 hens per replicate were used. The dietary treatments were: 1) Control - no supplementation of Zn, Mn, or Cu, 2) Zn, Mn, and Cu supplemented at 80-90-8 mg/kg from ITM, 3) Zn, Mn, and Cu supplemented at 80-90-8 mg/kg from ITM+OTM, 4) Zn, Mn, and Cu supplemented at 160-175-16 mg/kg from ITM, and 5) Zn, Mn, and Cu supplemented at 160-175-16 mg/kg from ITM+OTM. The trial lasted 84 days. The response criteria were egg weight, specific gravity, egg shell thickness, egg shell weight, albumen height, yolk height and width, Haugh units, yolk index, feed intake and feed conversion. Data were collected on three consecutive days at the end of each 28 day period. On the second day of each three day collection period, three yolks per replicate were collected and stored for analysis of Zn, Mn, and Cu content. In the first experiment, hens fed more than 100 mg/kg added Zn had reduced egg production and egg mass. Zinc content in the egg yolk was increased 23% with 150 mg/kg added Zn. In the second experiment there was no effect (P>0.05) of dietary treatment on egg production. During the first 28 day collection period, yolk Zn and Mn were highest (P<0.01) for hens fed the 160-175-16 mg/kg from ITM+OTM. In the third 28 day collection period, albumen height was highest (P<0.05) in eggs laid by hens fed the control diet and similar for hens fed all other treatment diets. Egg weight and egg mass were not affected by increasing dietary inclusion of Zn, Mn, and Cu. Feed intake was improved for the first 28 day collection period. Egg/kg of feed was increased when hens were fed the 80-90-8 mg/kg from ITM+OTM. Thus, Zn content of the egg yolk may be increased by the inclusion of ITM+OTM at rates above their requirement in layer diets.

Predation risk strongly influences the ecology and evolution of animal behaviors. However, anti-predator responses differ among species. Tradeoffs between anti-predator abilities and foraging efficiencies across habitats can promote the coexistence of ecologically similar species. In general, larger animals may better exploit riskier habitats; smaller animals, resources at low densities. I studied two montane ground squirrels Spermophilus lateralis and Tamias minimus in Colorado. Using food trays, I determined that the smaller T. minimus foraged more efficiently near meadow edges and was competitively superior to S. lateralis there. In contrast, S. lateralis had no preference for either edge or far habitat, but was competitively superior to T. minimus farther from the edge. I predicted, correctly, the exclusion of S. lateralis from meadows with primarily edge habitat. I proposed three alternatives to explain the observed patterns of habitat use: satiation, travel cost, or perceived predation risk. In a series of manipulations of energetic costs, protective cover, and predators, I eliminated all but the predation risk hypothesis. S. lateralis perceives less risk farther from the edge of the meadow than T. minimus. Faster harvesting and running speeds might decrease perceived predation risk. S. lateralis and T. minimus both experienced diminishing returns while foraging in food trays. Due to a higher encounter rate, S. lateralis harvested seeds significantly faster than T. minimus. S. lateralis also ran faster than T. minimus (3.14 m/s and 2.13 m/s, respectively). Gregarious animals may detect predators before solitary ones. I suggest that due to differences between sensory modes, this advantage occrues only to animals using vision. Thus, I predicted that gregariousness as a predator detection strategy should evolve only in diurnal animals. To test this, I mapped diurnal activity and gregarious behavior onto a phylogeny of eutherian mammals, and than calculated their degree of association. I found strong support for my prediction. This pattern may occur in other mobile animals. The data also suggest an association between larger body size and open habitat use among diurnal, gregarious organisms, paralleling a result from Colorado ground squirrels.

This study involved a new type of patterned string task in which a delay period was imposed between string presentation and opportunity to respond. In Experiments I and II, six squirrel monkeys were tested on parallel and crossed string problems in a Wisconsin General Test Apparatus. After the parallel or crossed string pattern was viewed by the subject for five seconds, one of three conditions was carried out: (a) a cover was placed over the ends of the strings thereby obscuring the food cup at the end of one string (far cover); (b) a cover was placed over the center portion of the strings allowing the subject to view the food cup but breaking the visual continuity of the strings (middle cover); (c) a cover was placed behind the string pattern thereby not obstructing the subject's view (no cover). After placing the cover according to one of three conditions, a Plexiglas screen was raised either immediately or after a five-second delay thus allowing the subject to respond. Results indicated that squirrel monkeys committed more errors under the far cover condition than under the no cover condition on parallel string patterns. On the crossed string pattern, squirrel monkeys manifested more position preference during the middle cover condition than during the no cover condition or during the far cover condition. In Experiment III, six capuchin monkeys were tested under 11 conditions on crossed string patterns. Eleven conditions were used to vary the lighting and the location of covering during the 12-second delay. Conditions 1 through 10 were conducted either in light or in dark when a cover was imposed during the beginning, middle, or end four seconds or during the beginning or end eight seconds. Regardless of light or dark conditions, capuchin monkeys manifested more correct responses when the full pattern was visible during the last four or the last eight seconds before the response. The result suggests that information received in the early part of the delay interval was used less efficiently than did that in the last part of the delay interval.

The corpus luteum (CL) is a tissue formed from the remnants of an ovulated follicle in the ovary, and it produces the progesterone needed for a healthy pregnancy. CL growth is highly dependent on a growing nutrient supply, and can be compared with the most aggressive vascular tumours. Angiogenesis, the growth of new blood vessels from existing ones, plays a key role in the growth and function of the CL. Inadequate angiogenesis has been linked to infertility in cows. The CL is composed of several vascular(e.g. endothelial cells (ECs), pericytes (PCs)), and avascular (e.g. luteal cells (LCs), immune cells) cell types, and several pro-angiogenic factors (e.g. Fibroblast Growth Factor 2, FGF2) found to be important in the angiogenic process. The objective of this thesis is to shed light on the cellular and extracellular level determinants of angiogenesis in the bovine CL. We begin with the relevant biological and mathematical literature in Chapter 1. In Chapter 2, an ordinary differential equation model of CL growth is introduced. We assume that the CL volume is a continuum of three cell types, ECs, LCs, and stromal cells (such as PCs). The fourth variable in the model, FGF2, enhances the EC proliferation rate. The model is able, by varying parameters such as the maximal proliferation rate of the ECs, to distinguish cases where the CL shifts from a ‘normal’ to a ‘pathological’ growth. In Chapter 3, we present in vitro CL published and novel studies from Robinson’s Lab. Preliminary results demonstrate interesting endothelial and pericyte behaviours regarding cell aggregation and sprout formation, which are the motivation for the next two Chapters. In these experimental studies, all the CL cell types were incorporated in the same in vitro culture, hence providing a closer approximation to the in vivo environment compared to other in vitro cultures which use only a single cell type (mainly ECs). However, this complicates matters in terms of distinguishing cell behaviours and factors which contribute on the overall cell dynamics. Therefore, in the Chapters 4 and 5 we use data from literature. In Chapter 4, by using the Cellular Potts Model (CPM) framework, we focus on EC-PC interactions, and particularly on the mechanism which is responsible for the EC growth inhibition. Our model incorporates two possible mechanisms for inhibition. That is, the mechanical cell-cell contact inhibition, and the inhibition mediated from diffusive TGF-b secreted once the two cell types come in contact. Interestingly, our model results suggest that the effective range of TGF-b is a crucial determinant of the degree of EC growth inhibition. Chapter 5, by using a CPM, is devoted to sprouting angiogenesis (the formation of new blood vessel). The dynamic interchange between stalk and tip EC phenotype is incorporated through the Notch signalling pathway, with the leading tip cell moving up macrophage-mediated VEGFA gradients in a non-uniform matrix environment. The model reproduces phenomena in sprouting angiogenesis, including sprout morphology, tip competition, and explains knockout experiments on the Notch signalling pathway. Finally, we close with Chapter 6 where we summarise the ain results from each chapter and propose model extensions for future directions.

Recent published work indicates a role for pre-slaughter dietary vitamin D supplementation to promote post mortem meat tenderization in cattle (Montgomery et al., 2000; Foote et al., 2004; Montogmery et al., 2004), pigs (Wilborn et al., 2004) and sheep (Wiegand et al., 2001; Boleman et al., 2004). The hypothesis being that vitamin D supplementation at supra-nutritional levels is able to cause increases in the calcium status of the animals, increasing the activity of the calcium-dependant proteolytic enzymes, the calpains, which are responsible for meat tenderization (Koohmaraie & Geesink, 2006). Muscle fibre type is a variable factor in muscle and is related to meat quality (Klont et al., 1998). Vitamin D has been suggested to play a role in regulating skeletal muscle function through the creation of vitamin D receptor knockout mice models (Endo et al., 2003) and observations that muscle weakness and falling risk in vitamin D deficient patients is linked to a loss of fast muscle fibres (Aniansson et al., 1986; Larsson et al., 1979; Sorenson et al., 1979; Sato et al., 2005). This thesis investigated two vitamin D pre-slaughter diet regimes on their effects on meat quality of the most economically important cut of the carcass, the longissimus dorsi (LD) muscle (Molina et al., 2005) and the expression of the calpain system. Trial 1 fed sheep vitamin D at 2.0 X 10[superscript]6 IU/day for four days prior to slaughter and found that this had no effect on shear force of LD chops. Calcium levels were unchanged but mRNA levels of calpain I and II were increased 3.7 and 10% respectively (P=0.099 and P=0.014) but there was no effect on calpastatin mRNA nor changes in the calpain system at the protein level. Trial 2 fed sheep the same dose of vitamin D for 7 days with an additional calcium bolus, resulting in a 10% increase in calcium concentrations of both serum and LD. Toughness of LD chops was increased (P<0.01), there was no effect on mRNA of the calpain system but there was an increase in the protein levels of calpain II and calpastatin by 16 and 17% respectively (P=0.05 and P=0.087). A microarray study of rat primary myoblasts treated with 1,25(OH)[subscript]2D[subscript]3 for 24 hours highlighted a number of responsive genes significantly up and down regulated 1.5 fold or more (P<0.05). Pathway analysis identified novel targets of 1,25(OH)[subscript]2D[subscript]3 with a possible relationship to muscle growth and function; these included C/EBPβ metallothionein 2A and the MAPK, ERK. Three muscle cell strains, the rat primary muscle cells, L6 Aston and C2C12, were assessed for myosin heavy chain (MHC) gene expression using semi-quantitative PCR and western blotting analysis. The muscle cell line demonstrating the broadest range of MHC genes relevant to mature muscle tissue was used for the final experiments; this was the C2C12 cell line demonstrating expression of the slow MHC 1/β, an isoform which was absent or showed much lower expression in the other cells. C2C12 cells treated with 1α(OH)D[subscript]3 for 48 hours at varying stages of development responded in changes in myogenic regulatory factors (MRFs), MHCs and novel target gene expression. Real time PCR analysis of C2C12 cells treated with the active vitamin D metabolite 1α(OH)D[subscript]3 affirmed C/EBPβ mRNA expression to be upregulated (P<0.001) and MAPK ERK 1/2 phosphorylation to be down regulated (P<0.001) by 1α(OH)D[subscript]3 in muscle cells. The effect of 1α(OH)D[subscript]3 in myoblasts was reduce proliferation and promote differentiation, as myotubes formed the effect of 1α(OH)D[subscript]3 was to promote MHC gene expression of an intermediate oxidative fibre type, increasing expression of MHC 1/β and 2A, decreasing MHC 2B. In conclusion, there is no apparent benefit of a pre-slaughter dietary vitamin D feeding regime on meat quality, but the active metabolites of vitamin D, 1α(OH)D[subscript]3 and 1,25(OH)[subscript]2D[subscript]3, exert changes in gene expression and MAPK signalling which are likely to affect muscle growth and fibre type, and is of relevance in terms of both meat quality and muscle function in the elderly.

The growth of ovarian follicles is well documented in terms of hormonal control, however the fluid dynamics of antral follicle growth is less well understood. Aquaporins (AQP) are transmembrane water channels which facilitate the passive movement of water. In mammals 13 AQPs have been identified in a vast range of tissue types. In terms of ovarian AQPs there is currently a paucity of information. Recent studies in rat, pig and human have revealed the presence of ovarian AQPs, but in doing so have also highlighted a lack of consensus on AQP-type and location. The main aim of this study was to investigate the potential role of AQP in antral follicle growth. The first objective was to identify tissue expression and localisation of AQP proteins in the bovine ovary. This required the characterisation of a panel of polyclonal serum antibodies. Immunohistochemistry (IHC) was then used to identify AQPs and to detect changes in protein expression during follicular growth. Aquaporin 1 was found in most vascular endothelium; it was plentiful in capillaries surrounding antral follicles and increased in abundance as vasculature increased with follicle development. Aquaporin 2 was not found in bovine ovarian tissue and the remaining antibodies were deemed too nonspecific to permit reliable conclusions. The second objective was to investigate, via RT-qPCR, mRNA levels of AQPs in granulosa and theca cells isolated from preantral, through to large preovulatory follicles. Transcripts of AQP 1, -3, -4, -5, -7 and -9 were detected in both the granulosa and theca of antral follicles with expression levels generally higher in theca. The expression of AQP 1, -5, -7 and -9 was initiated in the theca cells of early antral follicles. Finally, swelling assays using bovine and porcine granulosa cells demonstrated the ability of granulosa to swell. This was inhibited by HgCb which is characteristic of AQP function. Porcine granulosa cells incubated with androgen swelled by 27%, this effect was inhibited by hydroxyflutamide. Protein analysis of AQP5 via IHC and Western blotting showed possible up-regulation in porcine follicles. RTqPCR did not reveal AQP5 transcript, the reasons for this currently remain unclear. In conclusion, this study has revealed for the first time the involvement of AQPs in bovine ovarian follicle development, with AQPI, -5, -7 and -9 potentially playing a pivotal role in antrum formation. The AQP system in porcine granulosa cells is androgen sensitive however identification of the AQP/s responsible needs further investigation. The evidence from this investigation suggests a role for AQPs in facilitating follicle growth. The stage-dependent expression of certain AQPs and the androgen sensitive porcine granulosa cells reveals the possibility that AQPs may be modulated by follicle-regulating hormones.