ERA

Download the full-sized PDF of Effects of Photoperiod Management on Milk Production in Lactating Dairy CowsDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R30K26N8B

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Graduate Studies and Research, Faculty of

Collections

This file is in the following collections:

Theses and Dissertations

Effects of Photoperiod Management on Milk Production in Lactating Dairy Cows Open Access

Descriptions

Other title
Subject/Keyword
dairy cows
persistency
photoperiod
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Espinoza, Oswaldo S
Supervisor and department
Oba, Masahito (Agricultural, Food and Nutritional Science)
Examining committee member and department
Ambrose, Divakar (Agricultural, Food and Nutritional Science)
Zuidhof, Martin (Agricultural, Food and Nutritional Science)
Department
Department of Agricultural, Food, and Nutritional Science
Specialization
Animal Science
Date accepted
2016-02-04T11:53:58Z
Graduation date
2016-06
Degree
Master of Science
Degree level
Master's
Abstract
The goals of this research were to evaluate the interaction effects between photoperiod management and dietary grain allocation in lactating dairy cows and to determine if any relationships exist between photoperiod management and the persistency of lactation in selected dairy herds in Alberta. In study 1, there were no significant interaction effects between photoperiod management and dietary grain allocation on milk production, dry matter intake or body weight gain. Cows that were exposed to long day photoperiod (LP; 16 h of light, 8 h of darkness) increased milk yield by 2. 2 kg/d relative to the animals exposed to short day photoperiod (SP; 8 h of light, 16 h of darkness). However, galactopoietic responses to LP were only detected four weeks after initial light exposure; when cows were fed different diets, after adaptation to light treatment, the effect of LP on milk yield was not detected. Contrarily, cows fed high grain diets increased milk yield and dry matter intake compared with those fed low grain diets. In study 2, we found that animal exposure to light did not differ between summer and winter. Thus, farms that practiced photoperiod management were able to provide long day photoperiod throughout the year whereas cows in farms without photoperiod management were exposed to short photoperiod even in the summer months. The current study showed that persistency of lactation was not different for farms with photoperiod management compared with farms without it. Long day photoperiod can increase milk production in lactating dairy cows but animal responses may be affected to a greater extent by other management practices.
Language
English
DOI
doi:10.7939/R30K26N8B
Rights
This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for the purpose of private, scholarly or scientific research. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
Citation for previous publication

File Details

Date Uploaded
Date Modified
2016-02-04T18:54:08.770+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (PDF/A)
Mime type: application/pdf
File size: 2584549
Last modified: 2016:06:16 17:08:14-06:00
Filename: Espinoza_Oswaldo_S_201602_MSc.pdf
Original checksum: cadcf75711d9c225b3993399e7e1101b
Activity of users you follow
User Activity Date