Two strategies to reduce impact of heat stress on high producing dairy cows were examined. The first was to recalculate the temperature-humidity index (THI) using high producing dairy cows under diurnal summer conditions. This re-evaluation confirmed that current THI values underestimate the severity of heat stress levels. Therefore, cooling of dairy cattle during warm summer months should begin at a THI of 68. Previously, a THI equal to or greater than 72 has been used to define onset of heat stress. This study demonstrated that a THI greater than or equal to 68 is sufficient to increase body heat storage, respiration rate, skin evaporative heat loss, declines in feed intake and milk yield. A second objective involved three studies carried out to evaluate use of niacin in dairy cow rations to improve evaporative heat loss and resistance to heat stress. Niacin is known to cause intense vasodilation in human and lab species. We hypothesized that increasing vasodilation would improve evaporative heat loss in dairy cows. In the first niacin study, supplementation of lactating dairy cows with an encapsulated rumen by-pass form of niacin (NIASHURE™; Balchem Corporation, New Hampton, NY) at a dose of 12 g/d proved effective in alleviating some affects of heat stress during mild thermal stress. We hypothesized that encapsulated niacin would induce vasodilation effects documented in humans and lab animals increasing evaporative heat loss. Past research demonstrated that the possible mechanism for vasodilation affects seen by niacin were most likely due to prostaglandin D secretions. Niacin may act through increased prostaglandin D and E production and secretion by Langerhans cells which then act upon vascular endothelial prostaglandin D receptors to increase vasodilation. No studies have evaluated impact of encapsulated niacin on milk yield and composition during periods of thermal stress under commercial dairy conditions. The objective of the last study was to examine the effects of encapsulated niacin during heat stress on milk production and composition as well as core body temperatures under commercial conditions.

Thèse (M. Arch.)--Université Laval, 2003. / Bibliogr.: f. 159-163. Publié aussi en version électronique.

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Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-01-26T14:21:45Z No. of bitstreams: 1 arquivototal.pdf: 1043037 bytes, checksum: 92788ad999f4b08f8e2b154fa22c70b0 (MD5) / Made available in DSpace on 2016-01-26T14:21:45Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1043037 bytes, checksum: 92788ad999f4b08f8e2b154fa22c70b0 (MD5) Previous issue date: 2015-04-28 / Tinnitus is the perception of sound in the absence of a sound source. Occurring between 10-15% of the world population still needs better understanding of its pathophysiology, clinical comorbidities and more effective treatments. To this end, a better standardization of the use of evaluation methods in researches is required. This study aims the choice of most appropriate and easier use and interpretation methods. Initially an article in the form of a systematic review was performed in order to establish which evaluation methods of tinnitus are currently being used by scientific works. The aim of their uses was also identified. The THI, the EVA and the acuphenometry were the most used methods in 24 articles reviewed. The evaluation of therapy for tinnitus was the most frequent verified goal. A second article was performed to carry out a comparative analysis of these three methods. It was the THI, EVA (bother) and acuphenometry (loudness and pitch) in 44 patients with chronic tinnitus. A positive correlation of moderate intensity between them was found, being stronger between THI and VAS. It is concluded that the three evaluated tests keep moderate relation to each other. this should be taken into account when comparing with each other the results of different studies. The results of THI and EVA are be more strongly compared. Other future studies with more patients and more homogeneous sample can bring more contribution to the topic. / O zumbido é a percepção de um som na ausência de uma fonte sonora. Ocorre entre 10-15% da população mundial. Há a necessidade de melhor padronização do uso dos métodos avaliativos nas pesquisas, permitindo assim melhores comparações dos seus resultados. Este estudo visa contribuir na escolha dos métodos mais adequados e de mais fácil uso e interpretação. Inicialmente realizou-se um artigo de revisão sistemática, a fim de observar os métodos avaliativos do zumbido mais utilizados e o objetivo dos mesmos. Nos 24 artigos de revista analisados, o THI, a EVA e a acufenometria foram os métodos mais utilizados. A avaliação de terapia para o zumbido foi o mais frequente objetivo verificado. Um segundo artigo foi elaborado para analisar comparativamente estes 3 métodos. Aplicou-se o THI, EVA (incômodo) e acufenometria (loudness e pitch), em 44 pacientes com zumbido crônico. Encontrou-se uma correlação positiva de moderada intensidade entre eles, sendo mais forte entre o THI e a EVA. Concluiu-se que os 3 métodos avaliados guardam relação moderada entre si, devendo isso ser levado em consideração quando se comparam seus resultados entre si. Os escores do THI e da EVA podem mais fortemente serem comparados.

Aufgrund der zu erwartenden Klimaveränderungen, insbesondere durch eine Erhöhung der Temperaturen und einer Zunahme der Extremsituationen (Hitze- und Kälteperioden), sollte vermehrt über Effekte von Hitzestress auf das Wohlbefinden und Leistungsvermögen von Tieren nachgedacht werden. Um den Einfluss von klimatischen Bedingungen (Temperatur und Temperatur-Humiditäts Index) auf die Gesundheit und das Leistungsvermögen von Milchkühen zu untersuchen, wurden drei Studien durchgeführt. Zuerst wurden die Auswirkungen des Temperatur-Humiditäts Index (THI) auf die Behandlungsfrequenz von Milchkühen ermittelt. Hierfür wurden die Daten aus den Bestandsbüchern von 2003 und 2005 von acht Milchviehbetrieben ausgewertet. Die Behandlungen wurden in vier Komplexe unterteilt: Stoffwechsel, Fruchtbarkeit, Euter und Klauen, wobei 37,4% der Behandlungen zum Stoffwechsel-, 32,9% zum Euter-, 21,6% zum Fruchtbarkeits- und 8,1% zum Klauenkomplex gehörten. Es zeigten sich ein tendenzieller Anstieg der Stoffwechselinzidenzen mit steigendem THI und ein nicht signifikanter Anstieg von Euterbehandlungen mit abfallendem THI. Die zu analysierenden Daten bezüglich des Einflusses auf das Leistungsvermögen wurden im Rahmen eines einjährigen Feldversuches vom April 2010 bis März 2011 aufgenommen. Hierfür wurden aus einem Pool von niedersächsischen Milchviehbetrieben 20 Betriebe mit unterschiedlichen Haltungssystemen (gedämmte und ungedämmte Laufställe mit und ohne Weidegang) ausgewählt. Auf diesen Betrieben wurden klimatische Werte (Stalltemperatur, relative Stallluftfeuchtigkeit und THI) als auch Herden- bzw. tierindividuelle Leistungsdaten (4% fettkorrigierte Milchmenge (FCM), Milchinhaltsstoffe und somatischer Zellscore (SCS)) anhand von Tankmilchproben bzw. Einzeltiermilchproben im Rahmen der Milchleistungsprüfung erfasst. Insgesamt wiesen die Untersuchungen unterschiedlich hohe Hitzestresseffekte auf die Milchleistung, Milchinhaltsstoffe und den SCS in den verschiedenen Haltungssystemen auf. Für die Milchmenge ergaben sich Regressionskoeffizienten von -0,12 kg FCM/THI und -0,11 kg FCM/THI bei gedämmten Laufställen ohne und mit Weidegang sowie -0,21 kg FCM/THI für Außenklimaställe ohne und mit Weidegang. Für den SCS ergaben sich bei den Stallhaltungssystemen Regressionskoeffizienten von +0.03 SCS/THI für gedämmte Systeme und +0,07 SCS/THI für Außenklimaställe. Basierend auf den Ergebnissen der Arbeit kann geschlussfolgert werden, dass Milchkühe in Niedersachsen während der Sommermonate Hitzestress ausgesetzt waren, wohingegen sich die Auswirkungen je nach Haltungssystem differenziert darstellten. Des Weiteren konnte gezeigt werden, dass in dem System mit gedämmtem Dach niedrigere Auswirkungen mit steigendem THI zu finden waren.

The dissertation on the influence of temperature and humidity of the environment on the reproduction of the honey bee (Apis mellifera) describes the effect of the observed physical quantities on the entire bee during the growing season. Three habitats were monitored under different conditions. The measuring devices were always located inside and outside one colony of each habitat. In cooperation with colleagues from the Faculty of Electrical Engineering, ČVUT in Prague, the physical parameters monitoring was extended by monitoring the sound and weight of the hives - hive assemblies at the site located at the Agricultural Faculty of the University of South Bohemia. The data collection system in beehives was designed as a fully autonomous modular system. Measured data was processed and evaluated by statistical programs. The results showed that the hives observed differ in the number of bee queens found in the growing season and also in the number of frames found. Near-fetal temperatures were measured for correct development of the bee (32 °C to 36 °C). Colonies in the observed periods of 2014, 2015 and 2016 had to actively increase the relative humidity inside the hive in spring and summer. The colony reacts to changes in air temperature by varying intensity of sound. The results revealed the differences between the intensity of bee sounds in different temperature conditions. The highest sound intensity was detected at temperatures below 10 ° C (36.71 W.m-2), the lowest being at temperatures above 29.4 °C (26.25 W.m-2). The correlation coefficients were very low (r = 0.180) to medium (r = 0.463) and the correlation coefficient (r = 0.555) changed with a change in the temperature group. In order to evaluate the optimal conditions for honeybee rearing, the temperature and humidity monitoring can be used. The most suitable temperatures were in the range (29.5-34.3 °C) and temperatures above 34.4 °C. In terms of humidity, the temperature range (20-29.4 °C) and (29.5-34.3 °C) are the most appropriate. Changes in the observed values also affect the queen's bee in the colony. The data obtained from the long-term monitoring of these variables can help us to construct a THI index for bees, which would be a suitable tool to evaluate the optimal conditions for bees.

Thèse (M.Sc.)--Université Laval, 2005. / Titre de l'écran-titre (visionné le 28 mars 2007). Bibliogr.

Thesis (Ph.D.)--Pennsylvania State University, 2008. / Mode of access: World Wide Web. Thesis advisor: Mary Ann Stankiewicz.

Thèse (M. Arch.)--Université Laval, 2004. / Bibliogr.: f. [114]-121. Publié aussi en version électronique.

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