No description available.

No description available.

Das allgemeine Ziel der vorliegenden Doktorarbeit war es, den Zusammenhang von Fressverhalten, Futteraufnahme, Milchproduktion und Stoffwechselkrankheiten bei Milchkühen in der Frühlaktation zu untersuchen. Dafür wurden Daten von 70 laktierenden Deutschen Holstein-Friesischen Milchkühen (1. -7. Laktation) gesammelt. Das Fressverhalten wurde mittels eines elektronischen Fütterungssystems überwacht, welches die elektronische Kennung jeder einzelnen Kuh beinhaltete. Während der ersten Studie dieser Arbeit basierte die Analyse des Fressverhaltens der Milchkühe auf jedem Einzelbesuch; dabei war ein Besuch als die Zeit definiert, in der eine einzelne Kuh mit ihrem Kopf im Trog verweilte, unabhängig davon, wie die Kuh diese Zeit verbrachte. Während der zweiten und dritten Studie wurden die Besuche in Mahlzeiten unterteilt, die auf einem Mahlzeitenkriterium basieren, welches wie folgt berechnet wurde: Eine Mischung aus zwei normalen Verteilungen wurde an die Verteilungen der Intervallängen zwischen den Besuchen, die mittels des natürlichen Logarithmuses umgerechnet wurden waren, angepasst. Innerhalb dieser Studien wurde der Einfluss der Laktation, des Laktationsstatus und des Milchleistungsniveaus auf das Fressverhalten und die Futteraufnahme untersucht. Die letzte Studie bestimmte die Auswirkungen von Stoffwechselkrankheiten auf das Fressverhalten, die Futteraufnahme und die Milchproduktion. Die Ergebnisse deuten darauf hin, dass die Mahlzeit die wichtigere Einheit als der Einzelbesuch ist, um das Fressverhalten zu beschreiben. Laktationsnummer, Laktationsstatus und Milchleistungsniveau waren entscheidend für die Charakteristika des Fressverhaltens und die Futteraufnahme. Die höher Korrelation zwischen Fressverhalten, z.B. Dauer und Umfang einer Mahlzeit, verweisen darauf, dass das Messen der Fresszeit für das Berechnen der Futteraufnahme genutzt werden kann. Stoffwechselkrankheiten hatten einen entscheidenen Einfluss auf das Fressverhalten, die Futteraufnahme und die Milchproduktion. Die Beobachtung der Charakteristika des Fressverhaltens könnte bei der Früherkennung des bei Kühen bestehenden erhöhten Risikos an Stoffwechselstörungen hilfreich sein. / The overall objective of this PhD thesis was to investigate the relationships between feeding behaviour, feed intake, milk production, and metabolic-related production diseases of dairy cows during early lactation. Data from 70 lactating German Holstein Friesian dairy cows (parity 1 to 7) were collected. The feeding behaviour monitoring was conducted by using an electronic feeding system, which was equipped with an electronic identification of each individual cow. In the first study of this dissertation, the feeding behaviour of dairy cows was analysed based on the individual visits, with a visit being defined as the time spent by an individual cow with her head in one of the troughs regardless of how the cow spent that time. In the second and third studies, the visits were clustered in meals based on a “meal criterion”, which was calculated by fitting a mixture of two normal distributions to the distributions of the natural logarithm (LN)-transformed lengths of the interval between visits. In these studies, the effects of parity, stage of lactation, and milk yield level on feeding behaviour and feed intake were investigated. The final study determined the effects of metabolic-related production diseases on feeding behaviour, feed intake, and milk production. The results suggested that the meal is the more relevant unit than the individual visit for describing feeding behaviour. Parity, stage of lactation, and milk yield level had significant effects on feeding behaviour characteristics and feed intake. The high correlation between feeding behaviour such as meal duration and feed intake (meal size) suggests that measuring the time spent eating could be used to estimate the feed intake. Metabolic-related production diseases had significant effects on feeding behaviour, feed intake, and milk production. The monitoring of feeding behaviour characteristics might be helpful to detect the cows’ risk for metabolic-related production diseases at an early stage.

WWOX (WW domain-containing oxidoreductase) is a candidate tumor suppressor gene that has been shown to be involved in various cancers including breast, lung, prostate, gastric and hepatic. The Drosophila ortholog Wwox was identified and subjected to targeted ‘loss of function’ mutagenesis. The resulting mutants were found to be viable when homozygous with no obvious defects in the adult fly. As Wwox mutant flies were found to exhibit an increased sensitivity to ionising radiation (IR), a number of Wwox proteins specifically deleted or mutated at positions consisting of conserved functional protein motifs, or regions that are highly conserved among WWOX / Wwox homologs. The Wwox variants were tested for their ability to modify the IR sensitivity phenotype. In the course of this study, it was found that background mutations introduced during the generation of the mutant flies was responsible for the IR sensitivity phenotype. As a result, proteomic alterations resulting from changes in Wwox protein levels in Drosophila were investigated in order to ascertain the possible molecular functions of the Wwox protein. 2D-DIGE analysis was conducted on a number of different fly genotypes expressing differing levels of Wwox protein in both adult and embryonic flies. The proteomic changes resulting from lack of Wwox function as well as Wwox over-expression were detected with the proteins of interest identified by mass spectrometry (MS) using both MALDI-TOF/TOF-MS and LC-ESI-MS/MS. Label free quantitative MS analysis was also performed in order to determine the most abundant protein(s) in those spots found to contain multiple proteins. These proteomic studies identified changes in a wide variety of proteins with a significant number of metabolic proteins as well as proteins involved in oxidative stress response as a result of different levels of Wwox expression. Of particular interest, consistent changes in different isoforms of superoxide dismutase 1 (Sod1) were identified. Due to the known roles these proteins play in pro and anti-apoptotic pathways, it is possible that Sod1 and Wwox may work in concert to regulate the delicate balance of defence mechanisms in response to environmental stresses, particularly oxidative stress. The protein/gene targets identified in this work therefore offer some insights into normal Wwox function. / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2008

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.