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Effects of increased milking frequency on gene expression in the bovine mammary gland
BACKGROUND: Previous research has demonstrated that increased milking frequency of dairy cattle during the first few weeks of lactation enhances milk yield, and that the effect persists throughout the entire lactation period. The specific mechanisms controlling this increase in milk production are u...
Autores principales: | , , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
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BioMed Central
2008
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2518935/ https://www.ncbi.nlm.nih.gov/pubmed/18671851 http://dx.doi.org/10.1186/1471-2164-9-362 |
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author | Connor, Erin E Siferd, Stephen Elsasser, Theodore H Evock-Clover, Christina M Van Tassell, Curtis P Sonstegard, Tad S Fernandes, Violet M Capuco, Anthony V |
author_facet | Connor, Erin E Siferd, Stephen Elsasser, Theodore H Evock-Clover, Christina M Van Tassell, Curtis P Sonstegard, Tad S Fernandes, Violet M Capuco, Anthony V |
author_sort | Connor, Erin E |
collection | PubMed |
description | BACKGROUND: Previous research has demonstrated that increased milking frequency of dairy cattle during the first few weeks of lactation enhances milk yield, and that the effect persists throughout the entire lactation period. The specific mechanisms controlling this increase in milk production are unknown, but suggested pathways include increased mammary epithelial cell number, secretory capacity, and sensitivity to lactogenic hormones. We used serial analysis of gene expression (SAGE) and microarray analysis to identify changes in gene expression in the bovine mammary gland in response to 4× daily milking beginning at d 4 of lactation (IMF4) relative to glands milked 2× daily (Control) to gain insight into physiological changes occurring within the gland during more frequent milking. RESULTS: Results indicated changes in gene expression related to cell proliferation and differentiation, extracellular matrix (ECM) remodeling, metabolism, nutrient transport, and immune function in IMF4 versus Control cows. In addition, pathways expected to promote neovascularization within the gland appeared to be up regulated in IMF4 cows. To validate this finding, immunolocalization of Von Willebrandt's factor (VWF), an endothelial cell marker, and its co-localization with the nuclear proliferation antigen Ki67 were evaluated in mammary tissue sections at approximately d 7 and d 14 of lactation in cows milked 4× daily versus Controls to estimate endothelial cell abundance and proliferation within the gland. Consistent with expression of genes related to neovascularization, both abundance of VWF and its co-localization with Ki67 appeared to be elevated in cows milked 4× daily, suggesting persistent increased milk yield in response to increased milking frequency may be mediated or complemented by enhanced mammary ECM remodeling and neovascularization within the gland. CONCLUSION: Additional study is needed to determine whether changes in ECM remodeling and neovascularization of the mammary gland result in increased milk yield during increased milking frequency, or occur in response to an increased demand for milk production. Gene pathways identified by the current study will provide a basis for future investigations to identify factors mediating the effects of milking frequency on milk yield. |
format | Text |
id | pubmed-2518935 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2008 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-25189352008-08-22 Effects of increased milking frequency on gene expression in the bovine mammary gland Connor, Erin E Siferd, Stephen Elsasser, Theodore H Evock-Clover, Christina M Van Tassell, Curtis P Sonstegard, Tad S Fernandes, Violet M Capuco, Anthony V BMC Genomics Research Article BACKGROUND: Previous research has demonstrated that increased milking frequency of dairy cattle during the first few weeks of lactation enhances milk yield, and that the effect persists throughout the entire lactation period. The specific mechanisms controlling this increase in milk production are unknown, but suggested pathways include increased mammary epithelial cell number, secretory capacity, and sensitivity to lactogenic hormones. We used serial analysis of gene expression (SAGE) and microarray analysis to identify changes in gene expression in the bovine mammary gland in response to 4× daily milking beginning at d 4 of lactation (IMF4) relative to glands milked 2× daily (Control) to gain insight into physiological changes occurring within the gland during more frequent milking. RESULTS: Results indicated changes in gene expression related to cell proliferation and differentiation, extracellular matrix (ECM) remodeling, metabolism, nutrient transport, and immune function in IMF4 versus Control cows. In addition, pathways expected to promote neovascularization within the gland appeared to be up regulated in IMF4 cows. To validate this finding, immunolocalization of Von Willebrandt's factor (VWF), an endothelial cell marker, and its co-localization with the nuclear proliferation antigen Ki67 were evaluated in mammary tissue sections at approximately d 7 and d 14 of lactation in cows milked 4× daily versus Controls to estimate endothelial cell abundance and proliferation within the gland. Consistent with expression of genes related to neovascularization, both abundance of VWF and its co-localization with Ki67 appeared to be elevated in cows milked 4× daily, suggesting persistent increased milk yield in response to increased milking frequency may be mediated or complemented by enhanced mammary ECM remodeling and neovascularization within the gland. CONCLUSION: Additional study is needed to determine whether changes in ECM remodeling and neovascularization of the mammary gland result in increased milk yield during increased milking frequency, or occur in response to an increased demand for milk production. Gene pathways identified by the current study will provide a basis for future investigations to identify factors mediating the effects of milking frequency on milk yield. BioMed Central 2008-07-31 /pmc/articles/PMC2518935/ /pubmed/18671851 http://dx.doi.org/10.1186/1471-2164-9-362 Text en Copyright © 2008 Connor et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Article Connor, Erin E Siferd, Stephen Elsasser, Theodore H Evock-Clover, Christina M Van Tassell, Curtis P Sonstegard, Tad S Fernandes, Violet M Capuco, Anthony V Effects of increased milking frequency on gene expression in the bovine mammary gland |
title | Effects of increased milking frequency on gene expression in the bovine mammary gland |
title_full | Effects of increased milking frequency on gene expression in the bovine mammary gland |
title_fullStr | Effects of increased milking frequency on gene expression in the bovine mammary gland |
title_full_unstemmed | Effects of increased milking frequency on gene expression in the bovine mammary gland |
title_short | Effects of increased milking frequency on gene expression in the bovine mammary gland |
title_sort | effects of increased milking frequency on gene expression in the bovine mammary gland |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2518935/ https://www.ncbi.nlm.nih.gov/pubmed/18671851 http://dx.doi.org/10.1186/1471-2164-9-362 |
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