Animal & Avian Sciences Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2741
Browse
5 results
Search Results
Item Effects of barrier perches and stocking density on the behavior, space use, and leg health of the domestic fowl (Gallus gallus domesticus)(2009) Ventura, Beth Ann; Estevez, Inmaculada; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The objective of this study was to discern whether providing enrichment in the form of barrier perches across a range of densities might improve leg and foot health and promote behavioral expression and more even use of space in broilers. To investigate this, 2,088 day-old broiler chicks were randomly assigned to one of three barrier treatments at one of three densities. Effects on behavior, space use, foot and hock health, tibia fluctuating asymmetry, fear and production were subsequently assessed. Higher densities appeared to compromise broiler welfare, seen by increased tibia length asymmetry, poorer foot and hock health, suppression of activity, increased disturbances, and decreased use of space. Conversely, barrier perches - particularly simple barriers - appeared to improve footpad quality, promote increased perching and activity, decrease aggression and disturbances, and improve use of the central pen space, all without negatively impacting production traits.Item The effect of sperm mobility phenotype on fertility persistence in layer and broiler hens(2008) Baczynski, Kathleen; Estevez, Inmaculada; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Domestic fowl (Gallus gallus domesticus) were studied to identify accurate predictors of potential fertility in two lines of broiler breeder males along with fertility persistency in layer and broiler hens. Sixty-four Hy-Line layer and thirty-seven broiler breeder hens were AI with identical amounts of high or low mobility sperm from FG males. Morphological measurements were taken to determine relationships of these with semen volume, concentration, and mobility. We hypothesized that 1) semen quality would decline as males aged, 2) morphology would be positively correlated with semen quality, and 3) females AI with high mobility sperm would have a longer duration of fertility. Results revealed a significant age*line interaction for semen volume (p=0.0307), sperm concentration (p=0.0003), and sperm mobility (p=0.0405). Morphological measurements were correlated with different semen parameters in both lines. Fertility was positively correlated with semen quality. Sperm mobility influenced fertility in layer hens but not in broiler breeders.Item Personality Traits in the Budgerigar, Melopsittacus undulatus(2008) Callicrate, Taylor; Estevez, Inmaculada; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study investigated bold-shy personality in the budgerigar, Melopsittacus undulatus . Adult budgerigars (14 females, 9 males) fed either a control diet, or one supplemented with docosahexaenoic acid (DHA), were subjected to seven behavioral tests and two immunocompetence assays. Behavioral responses were categorized by context: fear, feeding, or activity. Correlations were obtained within contexts and among immunocompetence variables and all behavioral variables. Kruskal-Wallis analysis was used to investigate effects of gender and DHA on all variables. Budgerigars behaved consistently within activity and feeding contexts. Males had higher feeding rates, and their feeding responses were negatively correlated with a measure of innate immunity. Cluster analysis characterized birds by activity levels; bold birds were highly active and shy birds were less active. The results of this study suggest that budgerigars exhibit consistent behaviors in two contexts, feeding and activity, which are unrelated to each other, and that activity is the predominant personality trait.Item Effects of Moderate Calorie Restriction on Ovarian Function and Decline in Rhesus Monkeys(2006-04-27) Wu, Julie Mei-Fen; Ottinger, Mary Ann; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Calorie restriction (CR) has long been heralded as the only proven nutritional intervention for life extension. Recent data demonstrated that moderate CR also extended reproductive lifespan in female rats. The objectives of this project were to: 1) analyze general hormonal changes that occur with aging and menopause and 2) evaluate the effects (whether beneficial or detrimental) of moderate (30%) CR on ovarian function and decline in rhesus monkeys (Macaca mulatta). Hormone analyses demonstrated elevated FSH and reduced INHB in Old monkeys, prior to menstrual cycle irregularity and alterations in E2 or P4. Our data are the first demonstration of this hormonal event occurring in monkeys. Furthermore, moderate CR did not impair normal ovarian function or aging. Evaluation of three clinically available tests: day 3 FSH, the Clomiphene Citrate Challenge Test (CCCT) and the Exogenous FSH Ovarian Reserve Test (EFORT), demonstrated that CCCT is efficacious in monkeys, especially with the use of E2 and INHB. As such, CCCT is the most cost effective and best predictor of ovarian response. Responses were similar between CON and CR. Oocytes from old short-term CON and CR monkeys were collected and fertilized with spermatozoa collected from normal males. Interestingly, CR appears to prolong ovarian responsiveness to exogenous gonadotropins and improve embryonic development in vitro in old female rhesus monkeys. Microarray analysis of gene expression was conducted in luteinizing granulosa cells. A subset of responsive genes were identified that will require validation by via real time polymerase chain reaction (RT-PCR). These data will provide insight into potential mechanisms of direct action of CR on the ovary. Therefore, the results of this study have provided evidence for the utility of the rhesus monkey as a model for human menopause. Additionally, moderate CR did not impair normal reproductive function or decline. We also confirmed the efficacy of the CCCT in rhesus monkeys and recommend its use as a diagnostic tool. Finally, CR improved ovarian response to exogenous gonadotropins and has beneficial effects on oocyte quality and subsequent embryo development.Item The Captive Maned Wolf (Chrysocyon brachyurus): Nutritional Considerations with Emphasis on Management of Cystinuria(2005-05-12) Childs-Sanford, Sara; Angel, Roselina; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The intent of this project was to investigate options for improvement of a commercially manufactured prescription diet designed to reduce manifestation of clinical disease secondary to cystinuria in captive maned wolves in the United States. Diets high in plant-based protein, independent of sulfur amino acid content, resulted in an increase in average urine pH as well as a decrease in urine cystine crystal formation and cystine excretion in maned wolves. The rate of passage of digesta in maned wolves was very similar to that of domestic dogs on either the commercially available formula and an experimental formula. Differences in nutrient digestibility and mineral retention were seen between the wolves and the dogs, with dogs exhibiting higher digesitibility or retention in all cases. Six maned wolves maintained on these same two diets exhibited plasma taurine concentrations markedly lower than canine and feline normal reference ranges, implying that maned wolves may have a dietary requirement for taurine.