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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

The Relative Accuracy of Estimating the Production of Dairy Cows as Affected by Length of Testing Interval and Method of Estimating Production

Young, Ross M. 01 May 1964 (has links)
Production records for dairy cows were first based on the yield of butter for a seven day period any time during the lactation. Later, 365- day records based on production for one day in each calendar month came into general use. The records preferred at present are 305- day records based on monthly test day production, but calculated using the centering date method. The centering date estimate is based on milk and butterfat production from two consecutive milkings per month. The sampling day is centered as nearly as possible in the test month period which need not coincide with the calendar month. The reason for the general acceptance of the 305- day records is the desire of the dairyman to freshen the dairy cow annually, which means milking for ten months and dry for two months. Records calculated by the centering date method more nearly represent actual production than records calculated by other methods that have been used. It is generally accepted that if the present testing program is used properly it can be of great value to the dairy farmer from the standpoint of herd improvement and for selecting animals for a breeding program. However, only a small percentage of the dairymen take advantage of a testing program. One of the limiting factors has been the cost of testing and record keeping. It has been suggested that bimonthly or trimonthly test periods might provide as much information as the monthly testing interval and at the same time reduce the cost to the individual dairymen. It is reasonable to speculate that with reduced costs there would be an increased number of herds tested. This would help compensate the testing supervisor and data processing center for lost income resulting from less frequent testing, and at the same time provide more information for national sire proving programs. However, bimonthly or trimonthly testing have not been accepted because of the possiblilty of larger error being involved in individual records. This larger error occurs because the curvelinear shape of the lactation is not taken into account and a cow is given credit for the same production over the entire testing period, resulting in either under or over estimation of the record. Tho objective of this study is to measure the relative accuracy of estimating 305- day production of dairy cows by using different testing intervals and different methods to estimate production. Monthly, bimonthly, and trimonthly intervals are studied. Methods include the centering date method and three methods using factors designed to extend production from each test day to a 305-day estimate with the test day estimate averaged to determine the final estimate of production for 305 days.

Optimal feeding systems for small scale dairy herds in the North-West Province of South Africa

Manzana, Nonzwakazi Patience. January 2007 (has links)
Thesis (MSc. (Paraclinical Sciences)--University of Pretoria, 2007. / Includes bibliographical references. Also available in print format.

Relationships among estimated net income, herdlife and linear type traits in dairy cattle /

Weigel, Daniel J., January 1993 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 145-157). Also available via the Internet.

Using a statewide farm business management DACUM to determine the knowledge-base deficiencies of dairy farmers in northwest Wisconsin

Ranallo, Gerald W. January 1998 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 1998. / Includes bibliographical references.

Estimating amino acid limitations in California dairy rations and the effect of feeding a ruminally protected lysine supplement on animal performance

Swanepoel, Nadia. January 2009 (has links)
Thesis (M.Sc.(Agric.)(Animal Science: Animal Nutrition)) -- University of Pretoria, 2009. / Summary in English. Includes bibliographical references.

The impact of a national milk order for the United States an economic appraisal.

Gartner, Gerald John, January 1970 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Improving the management of dairy production systems in Cameroon

Bayemi Pougue, Henri Dieudonne. January 2009 (has links)
Thesis (Ph.D.(Animal and Wildlife Sciences)) -- University of Pretoria, 2009. / Summary in English. Includes bibliographical references.

The effect of summer feeding systems on the performance of spring-calving dairy cows

Burstedt, Erling. January 1983 (has links)
Thesis (doctoral)--Sveriges Lantbruksuniversitet, 1983. / Added t.p. and "List of corrections" leaves inserted. Includes three articles by the author which are referred to in the text. Includes bibliographical references.

Supplemental lipids of niacin in rations of dairy cows in early lactation

Ruegsegger, Gary J. January 1984 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. Includes tables. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 170-191).

An analysis of the differences in attitudes and accomplishments of dairy farmers in urban and rural towns of Connecticut, with implications for education

Hesseltine, W. R. January 1959 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 106-110).

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