{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/53772"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/53772","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"The errors associated with estimations of the reproductive efficiency of bulls based on non-return data","abstract":"Three statistical methods - multiple and linear regression, and analysis of variance - were used to interpret the data in this study. The results of a preliminary study indicated that there were several major sources of variation in the non-returns of bulls. These were seasonal differences, possible breed differences, and differences between bulls within a breed. In addition, there were differences in breeds in different seasons. Upon consideration of these data a regression study of 33 bulls was undertaken to ascertain the degree of relationship between the changes in the early and late non-returns to first services. Statistically, it was found that when both the 60-90 day and 30-60 day non-returns are available, the latter are of little practical value in predicting the changes in the 150-180 day non-returns. When only the 30-60 day figures are available they may be used with reasonable accuracy to “estimate” the final changes in the 150-180 day non-returns. An analysis of variance of the errors of estimate from the regression studies indicated that there are several assignable causes of variation in non-return estimates. These include differences between breeds as to the effect of season on reproductive efficiency, differences between bulls within a breed, and a significant difference in seasonal effect in different stations. The use of non-return data in estimating the reproductive efficiency of a bull is of value only when all factors that affect this reproductive efficiency are considered. This investigation shows the significance of some of the various factors to be considered.","abstract_html":"Three statistical methods - multiple and linear regression, and analysis of variance - were used to interpret the data in this study. The results of a preliminary study indicated that there were several major sources of variation in the non-returns of bulls. These were seasonal differences, possible breed differences, and differences between bulls within a breed. In addition, there were differences in breeds in different seasons. Upon consideration of these data a regression study of 33 bulls was undertaken to ascertain the degree of relationship between the changes in the early and late non-returns to first services. Statistically, it was found that when both the 60-90 day and 30-60 day non-returns are available, the latter are of little practical value in predicting the changes in the 150-180 day non-returns. When only the 30-60 day figures are available they may be used with reasonable accuracy to “estimate” the final changes in the 150-180 day non-returns. An analysis of variance of the errors of estimate from the regression studies indicated that there are several assignable causes of variation in non-return estimates. These include differences between breeds as to the effect of season on reproductive efficiency, differences between bulls within a breed, and a significant difference in seasonal effect in different stations. The use of non-return data in estimating the reproductive efficiency of a bull is of value only when all factors that affect this reproductive efficiency are considered. This investigation shows the significance of some of the various factors to be considered.","abstract_has_math":false,"creators":["Finkel, Peter William"],"institution":"Virginia Polytechnic Institute","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Dairy Husbandry","degree_department":"Dairy Husbandry","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1953,"date_issued":"1953","date_published":"1953","updated_at":"2026-07-22T22:20:41Z","subjects":[],"languages":["en_US"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/53772","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Dairy Husbandry"]},{"key":"dc:creator","label":"Author","values":["Finkel, Peter William"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-06-26T20:54:38Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-06-26T20:54:38Z"]},{"key":"dc:date.issued","label":"Date","values":["1953"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Dairy Husbandry"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/53772"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Three statistical methods - multiple and linear regression, and analysis of variance - were used to interpret the data in this study. The results of a preliminary study indicated that there were several major sources of variation in the non-returns of bulls. These were seasonal differences, possible breed differences, and differences between bulls within a breed. In addition, there were differences in breeds in different seasons. Upon consideration of these data a regression study of 33 bulls was undertaken to ascertain the degree of relationship between the changes in the early and late non-returns to first services. Statistically, it was found that when both the 60-90 day and 30-60 day non-returns are available, the latter are of little practical value in predicting the changes in the 150-180 day non-returns. When only the 30-60 day figures are available they may be used with reasonable accuracy to “estimate” the final changes in the 150-180 day non-returns. An analysis of variance of the errors of estimate from the regression studies indicated that there are several assignable causes of variation in non-return estimates. These include differences between breeds as to the effect of season on reproductive efficiency, differences between bulls within a breed, and a significant difference in seasonal effect in different stations. The use of non-return data in estimating the reproductive efficiency of a bull is of value only when all factors that affect this reproductive efficiency are considered. This investigation shows the significance of some of the various factors to be considered."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The errors associated with estimations of the reproductive efficiency of bulls based on non-return data"]}]}],"canonical_facts":{"dc:contributor.department":["Dairy Husbandry"],"dc:creator":["Finkel, Peter William"],"dc:date.accessioned":["2015-06-26T20:54:38Z"],"dc:date.available":["2015-06-26T20:54:38Z"],"dc:date.issued":["1953"],"dc:description.abstract":["Three statistical methods - multiple and linear regression, and analysis of variance - were used to interpret the data in this study. The results of a preliminary study indicated that there were several major sources of variation in the non-returns of bulls. These were seasonal differences, possible breed differences, and differences between bulls within a breed. In addition, there were differences in breeds in different seasons. Upon consideration of these data a regression study of 33 bulls was undertaken to ascertain the degree of relationship between the changes in the early and late non-returns to first services. Statistically, it was found that when both the 60-90 day and 30-60 day non-returns are available, the latter are of little practical value in predicting the changes in the 150-180 day non-returns. When only the 30-60 day figures are available they may be used with reasonable accuracy to “estimate” the final changes in the 150-180 day non-returns. An analysis of variance of the errors of estimate from the regression studies indicated that there are several assignable causes of variation in non-return estimates. These include differences between breeds as to the effect of season on reproductive efficiency, differences between bulls within a breed, and a significant difference in seasonal effect in different stations. The use of non-return data in estimating the reproductive efficiency of a bull is of value only when all factors that affect this reproductive efficiency are considered. 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