{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/23749"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/23749","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Periconceptional Heat Stress of Holstein Cows Affects Subsequent Production Parameters Measured During Adulthood","abstract":"Periconceptional heat stress is known to reduce the likelihood of establishing pregnancy; however, some conceptuses will survive. Of the pregnancies that continue to term, a proportion will be heifers which are retained as replacement animals. Alterations that occur as a result of exposure to thermal stress during such critical stages in development likely result in differential performance between the heat stress-conceieved (HSC) cows and thermoneutral-conceived (TNC) cows. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records (n =14,189,891) included cows born between 1977 and 2010 in FL, GA, SC, MS, LA, AL, and TX. Records were edited to include only Holsteins born between 2000 and 2010 (n = 704,419). Conception dates were calculated by subtracting 276 d from the recorded birth date. Records for cows conceived within the months of June, July, and August were retained as HSC cows; cows conceived within the months of December, January, and February were retained as TNC contemporaries. Significant differences (P<0.01) in mature-equivalent milk yield were observed in all first lactation cows, and in cows that were retained within one herd for three lactations. In the latter group alterations in milk compositions were statistically significant (P<0.01), but not biologically so. Furthermore, significant differences (P<0.01) in days open were observed in cows retained within one herd for three lactations. The effects of periconceptional heat stress were particularly noticeable during seasonal comparisons, with HSC cows seemingly having an advantage in subsequent episodes of heat stress.","abstract_html":"Periconceptional heat stress is known to reduce the likelihood of establishing pregnancy; however, some conceptuses will survive. Of the pregnancies that continue to term, a proportion will be heifers which are retained as replacement animals. Alterations that occur as a result of exposure to thermal stress during such critical stages in development likely result in differential performance between the heat stress-conceieved (HSC) cows and thermoneutral-conceived (TNC) cows. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records (n =14,189,891) included cows born between 1977 and 2010 in FL, GA, SC, MS, LA, AL, and TX. Records were edited to include only Holsteins born between 2000 and 2010 (n = 704,419). Conception dates were calculated by subtracting 276 d from the recorded birth date. Records for cows conceived within the months of June, July, and August were retained as HSC cows; cows conceived within the months of December, January, and February were retained as TNC contemporaries. Significant differences (P&lt;0.01) in mature-equivalent milk yield were observed in all first lactation cows, and in cows that were retained within one herd for three lactations. In the latter group alterations in milk compositions were statistically significant (P&lt;0.01), but not biologically so. Furthermore, significant differences (P&lt;0.01) in days open were observed in cows retained within one herd for three lactations. The effects of periconceptional heat stress were particularly noticeable during seasonal comparisons, with HSC cows seemingly having an advantage in subsequent episodes of heat stress.","abstract_has_math":false,"creators":["Brown, Britni M."],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Animal and Poultry Sciences","degree_department":"Animal and Poultry Sciences","school":null,"contributors":[],"advisors":[],"committee_chairs":["Rhoads, Michelle"],"committee_members":["James, Robert E.","Cassell, Bennet G.","Knight, James W."],"year":2013,"date_issued":"2013-09-04","date_published":"2013-09-04","updated_at":"2026-07-22T22:19:54Z","subjects":["dairy cow","heat stress","Reproduction","lactation"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:1602"],"render_values":[{"text":"vt_gsexam:1602","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/23749","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Rhoads, Michelle"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["James, Robert E.","Cassell, Bennet G.","Knight, James W."]},{"key":"dc:contributor.department","label":"Department","values":["Animal and Poultry Sciences"]},{"key":"dc:creator","label":"Author","values":["Brown, Britni M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2013-09-05T08:00:17Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2013-09-05T08:00:17Z"]},{"key":"dc:date.issued","label":"Date","values":["2013-09-04"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Animal and Poultry Sciences"]},{"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 and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["dairy cow","heat stress","Reproduction","lactation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"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.other","label":"Dc Identifier Other","values":["vt_gsexam:1602"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/23749"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Periconceptional heat stress is known to reduce the likelihood of establishing pregnancy; however, some conceptuses will survive. Of the pregnancies that continue to term, a proportion will be heifers which are retained as replacement animals. Alterations that occur as a result of exposure to thermal stress during such critical stages in development likely result in differential performance between the heat stress-conceieved (HSC) cows and thermoneutral-conceived (TNC) cows. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records (n =14,189,891) included cows born between 1977 and 2010 in FL, GA, SC, MS, LA, AL, and TX. Records were edited to include only Holsteins born between 2000 and 2010 (n = 704,419). Conception dates were calculated by subtracting 276 d from the recorded birth date. Records for cows conceived within the months of June, July, and August were retained as HSC cows; cows conceived within the months of December, January, and February were retained as TNC contemporaries. Significant differences (P<0.01) in mature-equivalent milk yield were observed in all first lactation cows, and in cows that were retained within one herd for three lactations. In the latter group alterations in milk compositions were statistically significant (P<0.01), but not biologically so. Furthermore, significant differences (P<0.01) in days open were observed in cows retained within one herd for three lactations. The effects of periconceptional heat stress were particularly noticeable during seasonal comparisons, with HSC cows seemingly having an advantage in subsequent episodes of heat stress."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Periconceptional Heat Stress of Holstein Cows Affects Subsequent Production Parameters Measured During Adulthood"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Rhoads, Michelle"],"dc:contributor.committeemember":["James, Robert E.","Cassell, Bennet G.","Knight, James W."],"dc:contributor.department":["Animal and Poultry Sciences"],"dc:creator":["Brown, Britni M."],"dc:date.accessioned":["2013-09-05T08:00:17Z"],"dc:date.available":["2013-09-05T08:00:17Z"],"dc:date.issued":["2013-09-04"],"dc:description.abstract":["Periconceptional heat stress is known to reduce the likelihood of establishing pregnancy; however, some conceptuses will survive. Of the pregnancies that continue to term, a proportion will be heifers which are retained as replacement animals. Alterations that occur as a result of exposure to thermal stress during such critical stages in development likely result in differential performance between the heat stress-conceieved (HSC) cows and thermoneutral-conceived (TNC) cows. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records (n =14,189,891) included cows born between 1977 and 2010 in FL, GA, SC, MS, LA, AL, and TX. Records were edited to include only Holsteins born between 2000 and 2010 (n = 704,419). Conception dates were calculated by subtracting 276 d from the recorded birth date. Records for cows conceived within the months of June, July, and August were retained as HSC cows; cows conceived within the months of December, January, and February were retained as TNC contemporaries. Significant differences (P<0.01) in mature-equivalent milk yield were observed in all first lactation cows, and in cows that were retained within one herd for three lactations. In the latter group alterations in milk compositions were statistically significant (P<0.01), but not biologically so. Furthermore, significant differences (P<0.01) in days open were observed in cows retained within one herd for three lactations. The effects of periconceptional heat stress were particularly noticeable during seasonal comparisons, with HSC cows seemingly having an advantage in subsequent episodes of heat stress."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:1602"],"dc:identifier.uri":["http://hdl.handle.net/10919/23749"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["dairy cow","heat stress","Reproduction","lactation"],"dc:title":["Periconceptional Heat Stress of Holstein Cows Affects Subsequent Production Parameters Measured During Adulthood"],"dc:type":["Thesis"],"thesis:degree_discipline":["Animal and Poultry Sciences"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:54Z"}