Late Gestation Heat Stress Effects on Cow Productive, Reproductive and Health Performance

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Material Information

Title:
Late Gestation Heat Stress Effects on Cow Productive, Reproductive and Health Performance
Physical Description:
1 online resource (163 p.)
Language:
english
Creator:
Thompson, Izabella Maria
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Animal Sciences
Committee Chair:
DAHL,GEOFFREY E
Committee Co-Chair:
HANSEN,PETER J
Committee Members:
THATCHER,WILLIAM W
DE VRIES,ALBERT
RISCO,CARLOS A

Subjects

Subjects / Keywords:
cow -- health -- heat -- performance -- reproduction -- stress
Animal Sciences -- Dissertations, Academic -- UF
Genre:
Animal Sciences thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
Exposure of dairy cows to heat stress and photoperiod during late gestation affects subsequent lactational performance. The aim of this dissertation was to study the effects of heat stress during this period on cow productive, reproductive and health performance. In Chapter 2 data from a commercial dairy were evaluated for seasonal effects in late gestation on health, reproduction and milk production in the subsequent lactation. Cows dried during cool months produced more milk and had improved reproductive and health performances than cows dried during hot months. In Chapter 3, cows were exposed to either cooling or heat stress under commercial settings during late gestation and the subsequent lactational performance was evaluated. Additionally, records of cows under cooling or heat stress during the dry period over 5 years were analyzed. No differences in milk production, occurrence of postpartum diseases and reproductive performance were observed under commercial settings. In contrast, analysia of data collected over 5 increased milk production in cows cooled during the dry period. For Chapter 4, the effects of dry period cooling on immune response after Streptococcus uberis intramammary challenge postpartum were evaluated. Cooled cows had greater white blood cells count and number of neutrophils in the blood during the challenge than heat stressed cows. Additionally, cooled cows had greater expression of cytokines in neutrophils. For Chapter 5, the effects of heat stress and photoperiod during the dry period on placental development were determined. Heat stress affected concentrations of pregnancy- specific protein B, but no differences were observed due to photoperiod lengths. For Chapter 6, the effect of a prolactin suppressor (cabergonline) on milk production of cows under heat stress during the dry period was tested. Cows exposed to heat stress and cabergoline did not have a periparturient prolactin surge, which resulted in decreased milk yield in the subsequent lactation. In conclusion, heat stress during the dry period affects late gestation placental development and subsequent milk production, health and reproductive performances. The response is related to the severity of heat stress. Changes in prolactin concentrations during the dry period are associated with production in the subsequent lactation.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Izabella Maria Thompson.
Thesis:
Thesis (Ph.D.)--University of Florida, 2014.
Local:
Adviser: DAHL,GEOFFREY E.
Local:
Co-adviser: HANSEN,PETER J.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2014-11-30

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2014
System ID:
UFE0046574:00001