Comparison of three estrus detection systems during summer heat stress in a large commercial dairy herd

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dc.contributor.authorPeralta, Oscar A.en
dc.contributor.committeechairNebel, Raymond L.en
dc.contributor.committeememberPearson, Ronald E.en
dc.contributor.committeememberSwecker, William S. Jr.en
dc.contributor.departmentDairy Scienceen
dc.date.accessioned2014-03-14T20:40:15Zen
dc.date.adate2003-09-24en
dc.date.available2014-03-14T20:40:15Zen
dc.date.issued2003-06-12en
dc.date.rdate2004-09-24en
dc.date.sdate2003-06-20en
dc.description.abstractThe objective of the study was to compare three systems for detection of estrus and combinations of these systems on a large commercial dairy (1000 lactating cows) during stress of summer heat. At 37 to 45 days in milk (DIM), 266 cows were fitted with a HeatWatch (HW) device (HeatWatch; DDx Inc., Boulder, CO), an activity (A) sensor (ALPRO; DeLaval Inc., Kansas City, MO), and observed visually (V) twice daily. Pregnancy status was determined by uterine palpation 35 to 49 d following artificial insemination (AI). The effects of DIM, parity, physical activity, standing events, months, AI technician, and interval between onset of estrus and AI on conception rate were determined using linear contrasts and logistic regression. Efficiencies for detection of estrus, determined by comparing detected periods of estrus with a theoretical total of 707 periods, were 45.8% (V), 33.2% (A), 40.3% (HW), and 71.6% for all three systems simultaneously. Conception rates (LSM ± SE) by method of detection were 16.7 ± 4.9 for HW, 19.8 ± 5.5 for A, 7.9 ± 3.4 for V, 16.3 ± 6.0 for V + A, 27.6 ± 4.6 for V + HW, 21.1 ± 4.9 for A + HW, and 21.9 ± 4.5 for V + A + HW. Conception rate and number of mounts decreased for cows in first versus second and third parity (P < 0.05). For periods of estrus detected by A, the lowest conception rate (P < 0.05) occurred >18 h after the onset of estrus (16.7 ± 7.9). The highest conception rate occurred with the combination of V + HW, which confirms the premise that combination of multiple systems enhances both the efficiency and accuracy of detection.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-06202003-122256en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-06202003-122256/en
dc.identifier.urihttp://hdl.handle.net/10919/33659en
dc.publisherVirginia Techen
dc.relation.haspartThesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectDetection of estrusen
dc.subjectefficiencyen
dc.subjectALPROen
dc.subjectHeatWatchen
dc.subjectheat stressen
dc.titleComparison of three estrus detection systems during summer heat stress in a large commercial dairy herden
dc.typeThesisen
thesis.degree.disciplineDairy Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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