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Dissertation
Designing Breeding Programs For Improving Milk Yield Performance Of Indigenous Genous Dairy Cattle In Sudan
(2022)
The overall aim of the present study was to design appropriate breeding programs for the sustainable improvement of Butana cattle in Sudan. Four studies were conducted, beginning with a comprehensive review of literature on indigenous dairy cattle breeding strategies in sub-Saharan Africa with a focus on the factors that contribute to their success or failure. It showed that crossbreeding of indigenous breeds with exotic breeds has been widely used for genetic improvement, but it largely failed under low-input ...
Aufsatz
Enlarging a training set for genomic selction by imputation of un-genotyped animals in populations of varying genetic architecture
(BioMed Central, 2013)
Background: The most common application of imputation is to infer genotypes of a high-density panel of markers on animals that are genotyped for a low-density panel. However, the increase in accuracy of genomic predictions resulting from an increase in the number of markers tends to reach a plateau beyond a certain density. Another application of imputation is to increase the size of the training set with un-genotyped animals. This strategy can be particularly successful when a set of closely related individuals are ...
Dissertation
Assessment of genetic diversity in local breeds
(2020-06)
The present study aimed at assessing genetic diversity in selected local livestock breeds in Northern Germany, and furthermore, examining some of the indices used in describing diversity in populations. The study begun with an assessment of genetic diversity in the German Angler (RVA) and Red-and-white dual-purpose (RDN) cattle breeds. Analyses of the RVA and RDN pedigrees, consisting of 93,078 and 184,358 records, respectively, revealed a number of Red Holstein (RH) sires that were influential in these breeds. Even ...
Aufsatz
Evaluation of breeding strategies for polledness in dairy cattle using a newly developed simulation framework for quantitative and Mendelian traits
(2016-06-29)
Background: Intensified selection of polled individuals has recently gained importance in predominantly horned dairy cattle breeds as an alternative to routine dehorning. The status quo of the current polled breeding pool of genetically-closely related artificial insemination sires with lower breeding values for performance traits raises questions regarding the effects of intensified selection based on this founder pool.
Methods: We developed a stochastic simulation framework that combines the stochastic simulation ...
Dissertation
Entwicklung eines ökonomisch ausgerichteten Zuchtprogramms für die bedrohte Schweinerasse „Bunte Bentheimer“
(2016-03-03)
Das Ziel dieser Arbeit war, ein ökonomisch ausgerichtetes Zuchtprogramm für die bedrohte Schweinerasse „Bunte Bentheimer“ (BB) zu entwickeln. Ein wesentlicher Bestandteil von Zuchtprogrammen für bedrohte Rassen ist der Erhalt der genetischen Diversität durch Vermeidung von weiterer Inzucht und Reduzierung des Inzuchtzuwachses. In Kapitel 2 wurde die Population der BB unter Berücksichtigung der vorhandenen Abstammungsinformationen in Bezug auf genetische Diversität, Inzucht und Verwandtschaft analysiert. Durchschnittlicher ...
Dissertation
Analyse von unerwünschten Arzneimittelwirkungen antibiotikahaltiger Euterinjektoren von Mastitiden bei Kühen der Rasse Holstein- Friesian unter Berücksichtigung von Leistungsniveau, Genetik und Produktionsbedingungen
(2015-08-04)
Das Ziel der vorliegenden Arbeit bestand darin, detailliert Wechselwirkungen zwischen dem binären Gesundheitsmerkmal klinischer Mastitis auf der einen und Produktionsmerkmalen (z. B. Milch-kg) und funktionalen Merkmalen (z.B. somatischer Zellgehalt) auf der anderen Seite unter simultaner Berücksichtigung von Umwelt und genetisch bedingten Einflussgrößen auf phänotypischer und genetischer Ebene abzubilden. Die Studie fokussierte auf innovative Aspekte der genetisch-statistischen Modellierung bzgl. der Anwendung von ...
Dissertation
Heat stress response for physiological traits in dairy and dual purpose cattle populations on phenotypic and genetic scales
(2016-02-23)
The main objective of this thesis was to determine the potential impact of heat stress (HS) on physiological traits of lactating cows and semen quality of bulls kept in a temperate climate. The thesis is comprised of three studies. An innovative statistical modeling aspect common to all three studies was the application of random regression methodology (RRM) to study the phenotypic and genetic trajectory of traits in dependency of a continuous temperature humidity index (THI).
In the first study, semen quality and ...