Frank Siewerdt

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Restriction of behavioral opportunities and uneven use of space are considerable welfare concerns in modern broiler production, particularly when birds are kept at high densities. We hypothesized that increased environmental complexity by provision of barrier perches would help address these issues by encouraging perching and enhancing use of the pen space(More)
The global poultry sector is divided into a large-scale commercial sector dominated by international, highly vertically integrated companies, and a small-scale sector that provides up to 90 percent of total poultry production in some of the least developed countries. The fast reproduction cycle, low unit costs, economies of scale in research and(More)
Artificial insemination plays a key role in the genetic management of elephants in zoos. Because freshly extended semen is typically used for artificial insemination in elephants, it has become imperative to optimize conditions for liquid storage and semen transport. The objectives of this study were to examine the interactions between different extenders(More)
The purpose of this study was to evaluate selection in lines of transgenic mice. Two replicates of lines that either carried or did not carry the sheep metallothionein-1a sheep growth hormone transgene (oMt1a-oGH) were established. The host lines had been previously selected for rapid growth or selected randomly. Within-litter selection for increased 8-wk(More)
Using lines of mice having undergone long-term selection for high and low growth, a large-sample (n ≈ 1000 F2) experiment was conducted to gain further understanding of the genetic architecture of complex polygenic traits. Composite interval mapping on data from 10-week-old F2 females (n = 439) detected 15 quantitative trait loci (QTLs) on 5 chromosomes(More)
Deterioration of footpad and hock condition and increased stress are important welfare concerns in high-density broiler production. It has been argued that environmental enrichment may help address these issues. We hypothesized that increasing environmental complexity by providing access to barrier perches across a range of densities should improve footpad(More)
OBJECTIVES To examine the associations between hardiness (defined as the ability to manage stress), depression, and emotional well-being and appetite in older adults. DESIGN Cross-sectional. SETTING Assisted-living facilities and senior centers in the Washington/Baltimore area. PARTICIPANTS Two hundred ninety-two adults aged 60 and older. (More)
Knowledge of genetic parameters is essential for improved reproductive management and increased yield. Quantitative analysis of genetic parameters is lacking for many breeds of buffaloes. This article provides the first estimate of genetic parameters for dual purpose (meat and milk) Brazilian Jaffarabadi buffaloes, using Bayesian inference. Data on milk(More)
The effect of individual and dam (maternal) inbreeding was quantified for preweaning traits in an Angus nucleus herd that has been closed to outside breeding for 70 yr. The effectiveness of 5 models (linear, quadratic, exponential, Michaelis-Menten, and Rumford-Newton) was evaluated for describing the effect of inbreeding on growth traits, hock length (HL),(More)
Title of Document: ELECTROENCEPHALOGRAPHY (EEG) AND MEASURES OF NOCICEPTION IN DOMESTIC CATTLE (Bos taurus) Kim Drnec, Doctor of Philosophy, 2013 Co-chairs: Associate Professor William R. Stricklin, Department of Animal and Avian Sciences/ Neuroscience and Cognitive Science Program Associate Professor Jonathan Z. Simon, Department of Electrical and computer(More)