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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Home-range fidelity and the effect of supplemental feeding on contact rates between white-tailed deer in southern Illinois

Rustand, Matthew Clifton 01 May 2010 (has links)
White-tailed deer (Odocoileous virginianus) are an important game animal and provide intrinsic value to many people. However, disease has become of great concern within white-tailed deer populations. Frequency of contract drives the establishment and spread of infectious diseases among susceptible hosts. Supplemental feed provided to increase white-tailed deer survival or create hunting opportunities, as well as bait stations to aid in capture of deer, may increase contact opportunities and disease transfer. My objective was to quantify the effects of bait sites on indirect contact between deer. I examined data from global positioning system (GPS) collars placed on 27 deer near Carbondale, Illinois, USA, from 2002 to 2005. Location data from GPS collars were used to ensure that I quantified contacts between deer in separate social groups, based on the volume of intersection of their spatial utilization distributions and correlation of movements. I matched 35 bait site locations and control sites not containing bait based on local land cover composition. Pairwise indirect contacts between deer were tabulated within a 10, 25, 50, 75, or 100-m buffer around each bait and control site. Indirect contact frequencies between bait and control sites were compared using mixed-model Poisson regression with deer pair as a random-effect variable and bait, joint utilization distribution (JUD), and year as fixed-effect variables. Contact frequencies did not differ significantly (P<0.05) between bait sites and control sites at any buffer distance, implying that small bait piles used to capture deer have minimal effect on contact frequencies. However, the effect of more consistent and greater quantities of food distributed during supplemental feeding programs should be studied further to determine its impact on contact rates and spatial distribution of deer. Understanding the spatial distribution of white-tailed deer is important to implement effective disease and population management within localized areas. The objective of this study was to measure the home-range fidelity of female deer in an exurban deer herd in southern Illinois. I compared location data of 7 deer that had been collected in 2004-2005 and 2008. I used the volume of intersection (VI) and percent of home range overlap to statistically compare the two annual home ranges for each deer. Deer were located used ground-based radiotelemetry and home ranges were characterized using a fixed kernel utilization distribution. Comparing home ranges between years, the mean VI was 0.45 with little variation (range 0.35-0.55). I found the mean percent overlap of 50% isopleths to be 47.1% (range 31.3-71.7%) and the mean overlap of 95% isopleths to be 62.0% (range 44.3-68.6%). My results indicate that female white-tailed deer on our study area showed strong home-range fidelity, which could permit disease and population management by removing deer and reducing local deer densities.
2

Effect of Time of Supplementation on Performance and Grazing Behavior of Grazing Steers

Claire, Olivia Mary 11 June 2020 (has links)
Beef cattle follow a daily, cyclical pattern of grazing, rumination, and digestion that coincides with their environment and season. Traditionally backgrounding operations hand feed any supplement in the morning. However, this practice may interrupt typical grazing patterns during early morning and subsequent rumination during the heat of the day. Self-fed concentrate feeds containing intake limiters are used to minimize the labor associated with hand feeding and allow cattle to eat throughout the day. The objectives of this experiment were to investigate the effect of supplement feeding time on performance and grazing behavior of backgrounded beef steers. Crossbred beef steers (n = 54; 7 ± 1 m of age; body weight, BW = 243 ± 2 kg) were sourced from a regional cattleman's association and grazed on tall fescue pasture (Festuca arundinacea) at the Southwest Virginia Agricultural Research and Extension Center in Glade Spring, VA from October 1 to November 7, 2019. Cattle were stratified by BW and source and allotted to 9 pasture groups (6 steers per pasture) in a randomized design. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Cattle were weighed on 2 consecutive days at the start and end of the experiment, and feed adjustments were made following three interim weigh-ins. Motion-sensing cameras were used to monitor cattle visits to the feeder and waterer portions of the pasture. Treatment did not impact (P = 0.13) BW, flesh condition score (FCS), dry matter intake (DMI), average daily gain (ADG), and backfat thickness. SELF steers were significantly more feed efficient than the AM supplemented groups (P = 0.03) and tended to be a greater G:F ratio (P = 0.08) for the PM supplemented groups vs. AM supplemented steers. Steers with access to a self-feeder showed behavioral differences to hand supplemented cattle, with more feeder visits in a 24 h period (P = 0.01) compared to AM and PM steers. Despite these behavioral observations, any disruption in natural grazing behavior was not dramatic enough to negatively influence backgrounded cattle growth performance. / Master of Science / Grazing beef cattle tend to follow a general pattern of grazing, rumination, and digestion that coincides with their environment and the time of year. Backgrounded cattle managed in pasture-based systems are traditionally offered supplemental feedings in the morning. However, this practice could be decreasing how efficiently cattle utilize forage resources. Natural grazing behaviors are more intense preceding the heat of the day and interruption of morning grazing bouts could decrease forage intake by causing cattle to come to the feeder to consume supplement feedings. To examine how feeding time potentially influences performance and grazing behavior of backgrounded beef cattle, 52 crossbred beef steers 7 to 8 months of age and weighing 243 kg were grazed on tall fescue pastures at the Southwest Virginia Agricultural Research and Extension Center from October 1 to November 8, 2019. Cattle were supplemented with either a commodity blend or cracked corn mixed with an intake limiter. Cattle were sourced from 4 local producers and allotted to 9 pastures by body weight (BW) and source. Pasture groups were randomly assigned to 1 of 3 treatments (3 pastures per treatment): 1) steers hand-fed supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a self-feeder supplement with an intake limiter (SELF). Hand-fed groups were fed a commercial commodity blend (38% corn gluten feed pellets, 30% cracked corn, 22% soy hull pellets, and 10% dried distillers grains) daily at 1.5% BW on an as fed basis. The SELF supplement was a blend of 70% cracked corn and 30% of an intake limiter-containing pellet that was formulated to maintain voluntary supplement intake at 1.5% BW on an as fed basis. Adjustments were made to the average BW of pasture groups, following three interim weigh dates at d 11, d 21, and d 30, to keep intake levels accurately at 1.5% BW. Flesh condition scores (FCS) were assigned on a scal of 1 to 9, with 1 considered emaciated and 9 excessively fat. 12th rib fat thickness (FT) was measured using an Aloka 500SC ultrasound. Both measurements were taken on the first and final day of the experiment. Motion-sensing cameras were installed in each pasture to capture pictures every one-minute following motion detection. Subsequent pictures were used to analysis the number of feed and water visits, along with time of day, in an attempt to characterize intake behavior. There were no major differences seen by treatment groups for BW, flesh condition score, DMI, ADG, and backfat thickness. Cattle on the SELF treatment had greater G:F than AM, with PM cattle being intermediate and not different than either. Steers with access to a self-feeder visited the feeder more than double the number of times in a 24 h period than either of the hand supplemented group. Despite differences in observed cattle behavior, any disruption in natural grazing behavior did not negatively influence performance of backgrounded steers.
3

Spatial and Feeding Ecology of the Fer-de-Lance (Bothrops asper) in Costa Rica

Wasko, Dennis Keith 14 April 2009 (has links)
Understanding the ways in which animals utilize space and obtain food are central themes in modern ecology. Formulating broad principles and elucidating the factors explaining such patterns are limited, however, by the availability of data from a broad range of species and systems. This problem especially true of snakes, a predator group about which even the most basic natural history data are often entirely lacking, even among abundant, widespread, and ecologically-important species. I studied the natural history and ecosystem role of one such species, the fer-de-lance (Bothrops asper) in lowland rainforest in Costa Rica. B. asper is a large, cryptic pitviper that is highly abundant in many Central American ecosystems and is strongly relevant to human health due to high incidence of snakebite, yet its biology under natural conditions is almost entirely undocumented. I used radiotelemetry to quantify home range, movement patterns, habitat usage, and foraging behavior. B. asper was found to have smaller home ranges and reduced movement patterns than similarly-sized temperate pitvipers, likely due to a greater reliance upon ambush foraging in patches of high prey density. Snakes also demonstrated strong selection for swamp habitat, which may reflect efforts to exploit frogs as a primary food source due to low availability of small mammals at the study site. I subsequently addressed the trophic status of this B. asper population using a supplemental-feeding experiment. In comparison to control snakes, individuals receiving supplemental food had smaller home ranges, shorter and less frequent movements, increased mass acquisition, and shifted to primarily forest rather than swamp habitat. These results support the suggestion that B. asper at the study site are strongly food-limited. Finally, I tested the hypothesis that fer-de-lance mediate local seed-predation rates by influencing habitat usage and foraging behavior of rodents. A series of behavioral experiments conflicted with many existing studies in failing to support this idea, as three rodent species demonstrated little snake avoidance, and none of likely ecological relevance. Collectively, this dissertation represents the first comprehensive field study of Bothrops asper and is among the first for any tropical snake, and suggests several avenues for future research.
4

Risk Factors for Poor Birth Outcomes in Moderately Malnourished Pregnant Women in Sierra Leone

Rodriguez, Candice A 01 March 2020 (has links) (PDF)
Background: Maternal malnutrition in developing countries is associated with adverse pregnancy and birth outcomes. Malnourished mothers are often faced with additional risk factors as a circumstance of poverty. Supplementary nutrition can improve the outcomes of both mother and infant. Identifying maternal nutritional and socioeconomic risk factors is critical for developing effective interventions. Objective: A secondary analysis to evaluate maternal risk factors associated with poor birth outcomes including pregnancy loss, low birth weight, stunting, and preterm delivery among moderately malnourished pregnant women in Sierra Leone. Maternal risk factors in the analysis are age, education, parity, BMI, MUAC, gestational weight gain, and recent exposure to malaria infection. Methods: Pregnant women were enrolled into a randomized controlled trial when presenting with a MUAC ≤ 23cm (N=1475). Demographic information was collected and women were randomly assigned two receive either a ready-to-use supplementary food (RUSF) or a corn-soy blended flour with an iron and folic acid supplement (CSB +IFA). Anthropometric measurements of height, weight, MUAC, and fundal height were measured every two weeks during pregnancy. Upon delivery the infant was measured for length, weight, MUAC, and head circumference and the mother was measured for MUAC. Infant outcomes of interest included stunting (length-for-age z-score Results: The mean age of enrolled pregnant women was 21.2 years with a mean BMI of 19.78 kg/m2. A total of 33.2% had never attended school. Controlling for weeks on treatment and BMI at enrollment, mothers receiving the RUSF treatment gained a mean 0.49 kg (p2 produced infants that were significantly smaller than women with a BMI ≥ 18.5 kg/cm2 . Similarly, infants born to women with a MUAC(p=0.004) and had a 0.26 cm smaller MUAC (p=0.008) compared to women with a MUAC ≤23. Additionally, for every one unit decrease in maternal MUAC, women has 1.2 greater odds of preterm delivery (p=0.022). Also, women with adequate weekly weight gain gave birth to infants with a 0.37 cm greater mean length (p=0.012), 7.0 g greater mean weight (p=0.030), and 0.08 cm greater mean MUAC (p=0.045) than women with inadequate weight gain. No association was found between recent exposure to malaria at enrollment and poor infant outcomes. Conclusion: In resource poor settings like Sierra Leone with high rates of maternal malnutrition and a high burden of stunting, LBW, and preterm delivery, use of RUSF improved maternal nutritional status but did not impact infant outcomes. The youngest adolescents had the most adverse infant outcomes. Education did not have the expected outcome, indicating other risk factors in this population may play a greater role in infant outcomes. Maternal risk factors of malnutrition such as BMI2and MUACpregnancy, women should be encouraged to gain adequate weight. Young primiparous adolescent are at the highest risk and interventions to postpone motherhood should be priority.
5

The effects of year-round supplemental feeding of white-tailed deer on sources of disease

Jacobson Huang, Miranda Hsiang-Ning 06 August 2021 (has links)
Supplemental feeding of deer is a common management action. However, concentrating animals, as feeding does, is known to promote the transmission of disease. We examined how feeding alters three sources of disease: aflatoxins, gastrointestinal parasites, and ticks. To do this, we paired 79 feeder sites throughout Mississippi with ecologically-equivalent sites without feeders. Wildlife visitation increased at feeders compared to sites without feeders. For aflatoxins, we sampled during the summer and hunting season and found low prevalence and levels in feeders and bagged/bulk feed. The greater concern was environmental exposure to aflatoxins. All corn piles exposed to environmental contamination in July contained toxic levels of aflatoxins after eight days. The environmental load of gastrointestinal parasites was elevated for coccidia (4x) and strongylids (3x). Finally, feeding reduced the number of ticks at feeder sites, but did not alter the prevalence of tick-borne diseases within captured ticks compared to sites without feeders.
6

Ecological determinants of roe deer (Capreolus capreolus) spatial behavior and movement in limiting conditions / Déterminants écologiques du comportement spatial et des mouvements des chevreuils en conditions limitantes

Ossi, Federico 13 January 2015 (has links)
Pour la grande majorité des grands herbivores vivant en régions tempérées, l'hiver est la saison la plus limitante à cause des effets combinés du manque de ressources et de la sévérité des conditions climatiques. Les espèces qui ne développent pas d'adaptations morphologiques ou physiologiques particulières pour faire face à la sévérité de l'hiver doivent mettre en place des mouvements et des tactiques d'utilisation de l'espace appropriés (comme par exemple les migrations). Plus spécifiquement, ces patrons d'utilisation de l'espace peuvent émerger à différentes échelles spatio-temporelles pour permettre aux individus d'accéder aux ressources dont ils ont besoin et d'échapper aux conditions climatiques défavorables. Ainsi, ces patrons d'utilisation de l'espace déterminent le sort des individus et la dynamique des populations. Une compréhension détaillée de la relation entre les facteurs limitants durant l'hiver et la réponse des animaux en termes de mouvements est prépondérante pour préserver et gérer les populations d'ongulés sauvages avec succès, tout spécialement dans le contexte actuel de changements climatiques rapides qui induisent des modifications importantes dans le paysage et la distribution des ressources (par exemple changement de patrons de couverture neigeuse en hiver). La comparaison de tactiques de mouvements sous différents scénarios de conditions environnementales, par exemple au moyen d'analyses à vaste échelle de l'aire de distribution de l'espèce cible, représente une approche pertinente pour mieux comprendre comment les mouvements des animaux répondent aux changements dans le paysage. Le chevreuil (Capreoluscapreolus) est une espèce modèle particulièrement intéressante pour étudier ces questions parce que la distribution de cette espèce couvre la plupart des pays d'Europe, grâce à sa forte plasticité écologique / For the majority of large ungulates living in temperate regions winter is the limiting season, because of the combined effects of lack of resource availability and severity of climatic conditions. Those species that did not develop any particular morphological and physiological adaptation to cope with winter severity may adopt movement and space use tactics instead (like e.g. migration). Specifically, these space use patterns may emerge at different spatiotemporal scales to allow individuals to accede the resources they need and escape unfavourable conditions, thus determining both individual fate and population dynamics. A detailed understanding of the relationship between limiting factors in wintertime, and individual movement response, is remarkable to preserve and manage wildlife successfully, especially in the context of fast-occurring climate change that induces important alterations in landscape and resource distribution (e.g. changes of snow cover patterns). The comparison of movement tactics under different environmental scenarios, e.g. by means of large –scale analysis at the species distribution range, represents a valuable approach to work in that direction and to assess the effects of landscape alteration on individual movement. Roe deer (Capreolus capreolus) is an excellent model species to investigate these issues, because its distribution range covers most of Europe, thanks to its high ecological plasticity. For those populations that live in northern and mountain environments, winter is the limiting season because roe deer lack any morphological and physiological adaptations to cope with winter severity. In spite of the adoption of specific movement tactics such as partial migration from summer to winter ranges, roe deer may still face limiting conditions in some areas of the distribution range exposed to winter severity

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