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dc.contributor.advisorCollier, Robert J.en_US
dc.contributor.advisorRhoads, Robert P.en_US
dc.contributor.advisorHadsell, Daryll L.en_US
dc.contributor.authorPuthenparampil Alex, Abraham
dc.creatorPuthenparampil Alex, Abrahamen_US
dc.date.accessioned2011-12-05T14:17:34Z
dc.date.available2011-12-05T14:17:34Z
dc.date.issued2009en_US
dc.identifier.urihttp://hdl.handle.net/10150/193425
dc.description.abstractSix primiparous Holstein cows were assigned to a half udder design (n=6) 40 days prior to parturition. Beginning at parturition, one udder half was milked once daily (24hr interval) and the other four times daily (6hr interval). Udder halves were biopsied at days 15, 60, 120, and 230 of lactation for mammary tissue to perform mitochondrial staining and apoptosis studies. Increasing the milking frequency from 1x to 4x elevated the 4x udder half milk yield at early (d1-45) (P<0.0001), mid (d46-150) (P<0.0001) and late (d151-230) (P<0.0001) lactation. Milk protein percent (P= 0.013), lactose percent (P=0.004) and SNF percent (P=0.006), were elevated in milk from 4x udder halves over milk from 1x udder halves. We did not detect an effect of increased milking frequency on milk fat percent (P=0.25); however, yield of all components was increased. Increased milking frequency also increased mitochondrial numbers in mammary cells from 4x udder half (P=0.002) compared to 1x. We did not detect an effect of increased milking frequency on mammary apoptosis percentage. We also did not detect a difference in the abundance of gene transcripts for SOCS1, SOCS2, SOCS3 and CIS in milk; but could find an increase in alpha-lactalbumin (P=0.04) and beta-casein (P=0.001) 4x udder half gene transcripts.
dc.language.isoENen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectBovine lactationen_US
dc.subjectMilking frequencyen_US
dc.subjectUdder half experimenten_US
dc.titleEffects of Milking Frequency on Milk Yield, Composition and Indices of Mammary Gland Metabolism in Lactating Dairy Cowsen_US
dc.typetexten_US
dc.typeElectronic Thesisen_US
dc.contributor.chairCollier, Robert J.en_US
dc.identifier.oclc659753435en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.levelmastersen_US
dc.contributor.committeememberRhoads, Robert P.en_US
dc.contributor.committeememberHadsell, Daryll L.en_US
dc.identifier.proquest10677en_US
thesis.degree.disciplineAnimal Sciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.nameM.S.en_US
refterms.dateFOA2018-08-24T17:47:22Z
html.description.abstractSix primiparous Holstein cows were assigned to a half udder design (n=6) 40 days prior to parturition. Beginning at parturition, one udder half was milked once daily (24hr interval) and the other four times daily (6hr interval). Udder halves were biopsied at days 15, 60, 120, and 230 of lactation for mammary tissue to perform mitochondrial staining and apoptosis studies. Increasing the milking frequency from 1x to 4x elevated the 4x udder half milk yield at early (d1-45) (P<0.0001), mid (d46-150) (P<0.0001) and late (d151-230) (P<0.0001) lactation. Milk protein percent (P= 0.013), lactose percent (P=0.004) and SNF percent (P=0.006), were elevated in milk from 4x udder halves over milk from 1x udder halves. We did not detect an effect of increased milking frequency on milk fat percent (P=0.25); however, yield of all components was increased. Increased milking frequency also increased mitochondrial numbers in mammary cells from 4x udder half (P=0.002) compared to 1x. We did not detect an effect of increased milking frequency on mammary apoptosis percentage. We also did not detect a difference in the abundance of gene transcripts for SOCS1, SOCS2, SOCS3 and CIS in milk; but could find an increase in alpha-lactalbumin (P=0.04) and beta-casein (P=0.001) 4x udder half gene transcripts.


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