128 research outputs found

    Evaluation of selection in developing inbred lines of swine

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    Agricultural Experiment Stations of Illinois, Indiana, Iowa, Minnesota, Missouri, Nebraska, Oklahoma, and Wisconsin and U.S. Department of Agriculture cooperatingDigitized 2007 AES.Includes bibliographical references (pages 58-[60])

    Influence of heterosis and plane of nutrition on rate and economy of gains, digestion and carcass composition of pigs

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    This report includes much of the material presented by senior author as a dissertation for the Doctor of Philosophy degree in August, 1951--P. [3].Digitized 2007 AES.Includes bibliographical references (pages 41-42)

    Components of performance in selecting for heterosis in swine

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    This bulletin is a report on Animal Husbandry Department project number 39 entitled 'Swine Improvement'--P. 6."This report includes much of the material presented by the senior author as a dissertation for the Doctor of Philosophy degree in July, 1952"--P. [7].Digitized 2007 AES.Includes bibliographical references (pages 67-68)

    Biological Efficiency Differences Among \u3ci\u3eBos taurus\u3c/i\u3e x \u3ci\u3eBos taurus\u3c/i\u3e and \u3ci\u3eBos indicus\u3c/i\u3e x \u3ci\u3eBos taurus\u3c/i\u3e F\u3csub\u3e1\u3c/sub\u3e-Cross Cows

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    Matching germplasm to resources through designed crossbreeding programs can contribute to optimum beef production efficiency. This is particularly true in light of the wide diversity of environmental conditions encountered by beef producers in the U.S. This approach requires considerable knowledge about genetic diversity among breeds in components of performance and furthermore how those components interact to influence life-cycle efficiency in the production setting. It was largely this identified need, coupled with the importation of a number of new breeds from continental Europe, that gave impetus for the establishment of the Germplasm Evaluation (GPE) Program. In Cycles I and II of the GPE program, increases in cow output associated with higher breed potential for growth rate and milk production were largely offset by equivalent or greater increases in feed requirements for maintenance and lactation. Additionally, in Cycle III, output of calf weaned per cow in the breeding herd was high for Bos indicus x Bos taurus crosses relative to Bos taurus crosses. More information is needed to evaluate F1 cross of Bos taurus versus Bos indicus x Bos taurus sources of germplasm. Therefore, this study was conducted to: 1) estimate input/output components, and 2) estimate life-cycle efficiency of Cycle III breeds representing these types of F1 cross females

    Influence of inbreeding, age and growth rate of sows on sexual maturity, rate of ovulation, fertilization and embryonic survival

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    This report includes most of the material presented by the senior author as a Doctoral dissertation--P. [3].Digitized 2007 AES.Includes bibliographical references (pages 39-40)

    Effects of Managing Heifers to Calve First at Two \u3ci\u3evs\u3c/i\u3e Three Years of Age on Longevity and Lifetime Production of Beef Cows

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    Resources used by cow herds for beef production vary greatly. To optimize reproduction and other production characteristics in the cow herd, breeding and management should be matched with the feed resources available for production. One management decision is whether to develop replacement females to calve first as 2-year-olds or as 3-year-olds. When feed resources are limited or expensive relative to other costs and value of output, it may be economical to delay the first calving until 3 years of age. When feed resources are adequate to support rapid growth and development of heifers and thus to reduce age at puberty to 14 months of age or less, then calving at 2 years of age may be optimum. another management decision is whether or not cows should be culled the first time they are open, or held over for another opportunity to breed (in lieu of keeping an additional replacement heifer). This study was conducted to evaluate effects of 2-year-old vs 3-year-old first calf management on longevity and lifetime production of cows and on current economics of beef production

    Effects of Heterosis on Longevity in Beef Cattle

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    Longevity can be important to the economic efficiency of beef production. The longer cows remain productive in a herd, the fewer the number of replacement heifers needed and the greater the calf output per cow maintained. In this way, more heifers can be sold for feeding and slaughter, and the cost of growing out replacement females to a productive age is reduced. Less culling of infertile cows also increases output per cow exposed. This study was conducted to determine effects of heterosis on longevity and associated factors in crosses of the Hereford, Angus, and Shorthorn breeds

    Reproductive development and performance of inbred and crossbred boars

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    This report includes much of the material presented by the senior author as a doctoral dissertation--P. [3].Digitized 2007 AES.Includes bibliographical references (page 56)

    Experiences and attitudes of Dutch rheumatologists and oncologists with regard to their patients’ health-related Internet use

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    The objective of this study is to explore the experiences and attitudes of rheumatologists and oncologists with regard to their patients’ health-related Internet use. In addition, we explored how often physicians referred their patients to health-related Internet sites. We sent a questionnaire to all the rheumatologists and oncologists in the Netherlands. The questionnaire included questions concerning demographics, experiences with patients’ health-related Internet use, referral behavior, and attitudes to the consequences of patients’ health-related Internet use (for patients themselves, the physician-patient relationship and the health care). The response rate was 46% (N = 238). Of these respondents, 134 practiced as a rheumatologist and 104 as an oncologist. Almost all physicians encountered their patients raising information from the Internet during a consultation. They were not, however, confronted with their patients’ health-related Internet use on a daily basis. Physicians had a moderately positive attitude towards the consequences of patients’ health-related Internet use, the physician-patient relationship and the health care. Oncologists were significantly less positive than rheumatologists about the consequences of health-related Internet use. Most of the physicians had never (32%) or only sometimes (42%) referred a patient to a health-related Internet site. Most physicians (53%) found it difficult to stay up-to-date with reliable Internet sites for patients. Physicians are moderately positive about their patients’ health-related Internet use but only seldom refer them to relevant sites. Offering an up-to-date site with accredited websites for patients might help physicians refer their patients

    Moving to capture children’s attention: developing a methodology for measuring visuomotor attention

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    Attention underpins many activities integral to a child’s development. However, methodological limitations currently make large-scale assessment of children’s attentional skill impractical, costly and lacking in ecological validity. Consequently we developed a measure of ‘Visual Motor Attention’ (VMA) - a construct defined as the ability to sustain and adapt visuomotor behaviour in response to task-relevant visual information. In a series of experiments, we evaluated the capability of our method to measure attentional processes and their contributions in guiding visuomotor behaviour. Experiment 1 established the method’s core features (ability to track stimuli moving on a tablet-computer screen with a hand-held stylus) and demonstrated its sensitivity to principled manipulations in adults’ attentional load. Experiment 2 standardised a format suitable for use with children and showed construct validity by capturing developmental changes in executive attention processes. Experiment 3 tested the hypothesis that children with and without coordination difficulties would show qualitatively different response patterns, finding an interaction between the cognitive and motor factors underpinning responses. Experiment 4 identified associations between VMA performance and existing standardised attention assessments and thereby confirmed convergent validity. These results establish a novel approach to measuring childhood attention that can produce meaningful functional assessments that capture how attention operates in an ecologically valid context (i.e. attention's specific contribution to visuomanual action)
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