Bos taurus
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ABSTRACT:
PROVIDER: PRJNA138051 | ENA |
REPOSITORIES: ENA
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Project description:Four-times daily milking during the first 3 weeks of lactation elicits an increase in milk yield, which persists through late lactation even after twice-daily milking is imposed. We hypothesized that this milk yield response would be associated with changes in mammary proliferation, apoptosis, and gene expression, which would persist throughout lactation. Six multiparous cows were assigned to unilateral frequent milking (UFM; twice daily milking of the left udder half (2X), four-times daily milking of the right udder half (4X)) on days 1 to 21 of lactation, followed by 2X thereafter. Udder halves initially milked 4X produced more milk than those milked 2X during, and after UFM treatment, through 180 days in milk (DIM). To determine the mechanisms involved in the persistent milk yield response, we obtained mammary biopsies from both udder halves at 21, 23, and 40 DIM. Rates of [3H]-thymidine incorporation into DNA in vitro and mammary cell apoptosis were not affected by UFM or DIM. Using Affymetrix GeneChipM-BM-. Bovine Genome Arrays, we determined that the differential expression (4X vs. 2X) of 18 genes was significantly affected by DIM. Within the group of 18 differentially expressed genes, we identified a cluster of 15 genes with a similar temporal pattern of differential expression. Nine of the genes in the cluster remained differentially expressed at 40 DIM, indicating that they may be involved in the persistent milk yield response. Among the genes in the cluster were chitinase 3-like (CHI3L)-1, clusterin, early growth response (EGR)-1, and sex determining region Y-box (SOX)-4. These genes have been associated with mammary development, differentiation and remodeling; all of which may be functionally related to the increase in milk yield. We conclude that frequent milking during early lactation does not alter mammary growth but is associated with changes in mammary expression of 18 genes. Future experiments will determine the function of these genes in the mammary gland, and will clarify their role in the autocrine regulation of milk production and long-term alteration of mammary function. 36 samples from 6 cows; 3 timepoints
2014-01-01 | E-GEOD-27851 | biostudies-arrayexpress
Project description:BACKGROUND: The lactating mammary gland responds to changes in milking frequency by modulating milk production. This response is locally regulated and, in dairy cows, the udder is particularly sensitive during early lactation. Relative to cows milked twice-daily throughout lactation, those milked four-times-daily for just the first 3 weeks of lactation produce more milk throughout that lactation. We hypothesized that the milk yield response would be associated with increased mammary cell turnover and changes in gene expression during frequent milking and persisting thereafter. Cows were assigned to unilateral frequent milking (UFM; left udder halves milked twice-daily; right udder halves milked four-times daily) on days 1 to 21 of lactation, followed by twice-daily milking for the remainder of lactation. Relative to udder halves milked twice-daily, those milked four-times produced more milk during UFM; the difference in milk yield declined acutely upon cessation of UFM after day 21, but remained significantly elevated thereafter. We obtained mammary biopsies from both udder halves on days 21, 23, and 40 of lactation. RESULTS: Mammary cell proliferation and apoptosis were not affected by milking frequency. We identified 75 genes that were differentially expressed between paired udder halves on day 21 but exhibited a reversal of differential expression on day 23. Among those genes, we identified four clusters characterized by similar temporal patterns of differential expression. Two clusters (11 genes) were positively correlated with changes in milk yield and were differentially expressed on day 21 of lactation only, indicating involvement in the initial milk yield response. Two other clusters (64 genes) were negatively correlated with changes in milk yield. Twenty-nine of the 75 genes were also differentially expressed on day 40 of lactation. CONCLUSIONS: Changes in milking frequency during early lactation did not alter mammary cell population dynamics, but were associated with coordinated changes in mammary expression of at least 75 genes. Twenty-nine of those genes were differentially expressed 19 days after cessation of treatment, implicating them in the persistent milk yield response. We conclude that we have identified a novel transcriptional signature that may mediate the adaptive response to changes in milking frequency.
2014-01-01 | GSE27851 | GEO
Project description:The acute milk yield response to frequent milking in early lactation is mediated by genes transiently regulated by milk removal.
| PRJNA137019 | ENA
Project description:Milking dairy cows four times daily (4X) instead of twice daily (2X) during early lactation stimulates an increase in milk yield that partly persists through late lactation; however, the mechanisms behind this response are unknown. We hypothesized that the acute mammary response to regular milkings would be transient and would involve different genes from those that may be specifically regulated in response to 4X. Nine multiparous cows were assigned at parturition to unilateral frequent milking (UFM; 2X of the left udder half, 4X of the right udder half). Mammary biopsies were obtained from both rear quarters at 5 days in milk (DIM), immediately after 4X glands had been milked (Experiment 1; n = 4 cows), or 2.5 h after both udder halves had last been milked (Experiment 2; n = 5 cows). Affymetrix GeneChip® Bovine Genome Arrays were used to measure gene expression. Eight hundred and fifty five genes were differentially expressed in mammary tissue between 2X vs. 4X glands of cows in experiment 1 (FDR ≤ 0.05), whereas none were differentially expressed in experiment 2 using the same criterion. We conclude that there is an acute transcriptional response to milk removal, but 4X milking did not elicit differential expression of unique genes. Therefore, there does not appear to be a sustained transcriptional response to 4X milking on day 5 of lactation. Using a differential expression plot of data from both experiments, as well as qRT-PCR, we identified at least two genes that may be responsive to both milk removal and to 4X milking. Therefore, the milk yield response to 4X milking may be mediated by genes that are acutely regulated by removal of milk from the mammary gland.
2012-02-27 | GSE27380 | GEO
Project description:Milking dairy cows four times daily (4X) instead of twice daily (2X) during early lactation stimulates an increase in milk yield that partly persists through late lactation; however, the mechanisms behind this response are unknown. We hypothesized that the acute mammary response to regular milkings would be transient and would involve different genes from those that may be specifically regulated in response to 4X. Nine multiparous cows were assigned at parturition to unilateral frequent milking (UFM; 2X of the left udder half, 4X of the right udder half). Mammary biopsies were obtained from both rear quarters at 5 days in milk (DIM), immediately after 4X glands had been milked (Experiment 1; n = 4 cows), or 2.5 h after both udder halves had last been milked (Experiment 2; n = 5 cows). Affymetrix GeneChipM-BM-. Bovine Genome Arrays were used to measure gene expression. Eight hundred and fifty five genes were differentially expressed in mammary tissue between 2X vs. 4X glands of cows in experiment 1 (FDR M-bM-^IM-$ 0.05), whereas none were differentially expressed in experiment 2 using the same criterion. We conclude that there is an acute transcriptional response to milk removal, but 4X milking did not elicit differential expression of unique genes. Therefore, there does not appear to be a sustained transcriptional response to 4X milking on day 5 of lactation. Using a differential expression plot of data from both experiments, as well as qRT-PCR, we identified at least two genes that may be responsive to both milk removal and to 4X milking. Therefore, the milk yield response to 4X milking may be mediated by genes that are acutely regulated by removal of milk from the mammary gland. 8 samples from 4 cows in experiment 1; 6 samples from 3 cows in experiment 2
2012-02-27 | E-GEOD-27380 | biostudies-arrayexpress
Project description:Transcript profiling was performed by Affymetrix microarray analysis and SAGE to characterize changes in gene expression in the bovine mammary gland in response to 4× versus 2× daily milking during the first week of lactation. These changes in gene expression may contribute to the increased milk production observed in response to increased milking frequency. Our results indicate that increased milking frequency alters expression of genes in the mammary gland related to increased extracellular matrix remodeling, neovascularization, metabolism, cell proliferation and apoptosis. Keywords: Physiological response to stimulus
2007-12-23 | GSE9344 | GEO
Project description:Regulation of milk synthesis and secretion is controlled mostly through local (intra-mammary) mechanisms. To gain insight into the molecular pathways comprising this response, an analysis of mammary gene expression was conducted in 12 lactating cows shifted from twice daily to once daily milking. Tissues were sampled by biopsy from adjacent mammary quarters of these animals during the two milking frequencies, allowing changes in gene expression to be assessed within each animal. Using bovine-specific, oligonucleotide arrays representing 21,495 unique transcripts, a range of differentially expressed genes were found as a result of less frequent milk removal. A total of 12 microarrays were used in this study. Each array was hybridized with RNA derived from a mammary sample taken at each biopsy time point, such that the twice-a-day milked sample and once-a-day milked sample were contained on the same slide for each animal (12 animals). Six of the microarrays represented animals previously shown to demonstrate a âlargeâ reduction in milk yield, whereas the other six arrays represented animals that previously displayed a âsmallâ reduction in milk yield when milked once per day. Half of each yield loss group (three animals) was represented by once-a-day milked/twice-daily-milked samples for Cy5/Cy3 labelling, with the other half labelled with the opposite dye configuration. This meant that six of 12 arrays were 'dye swapped', but with biological replicates as opposed to identical replicates.
2010-05-16 | E-GEOD-16876 | biostudies-arrayexpress
Project description:Regulation of milk synthesis and secretion is controlled mostly through local (intra-mammary) mechanisms. To gain insight into the molecular pathways comprising this response, an analysis of mammary gene expression was conducted in 12 lactating cows shifted from twice daily to once daily milking. Tissues were sampled by biopsy from adjacent mammary quarters of these animals during the two milking frequencies, allowing changes in gene expression to be assessed within each animal. Using bovine-specific, oligonucleotide arrays representing 21,495 unique transcripts, a range of differentially expressed genes were found as a result of less frequent milk removal.
2009-07-01 | GSE16876 | GEO
Project description:Transcript profiling was performed by Affymetrix microarray analysis and SAGE to characterize changes in gene expression in the bovine mammary gland in response to 4× versus 2× daily milking during the first week of lactation. These changes in gene expression may contribute to the increased milk production observed in response to increased milking frequency. Our results indicate that increased milking frequency alters expression of genes in the mammary gland related to increased extracellular matrix remodeling, neovascularization, metabolism, cell proliferation and apoptosis. Keywords: Physiological response to stimulus Multiparous Holstein cows were milked either 2× daily (Control, n = 3) or 2× daily from day 1 to 3 of lactation, and 4× daily beginning at day 4 of lactation until day 21 post partum (IMF4, n = 4). The milking intervals were approximately 12 hours for Control cows and 9, 3, 9, and 3 hours, respectively, for IMF4 cows. Mammary biopsies were obtained at approximately day 7 of lactation for extraction of total RNA and subsequent transcript profiling my microarray (Affymetrix). Pooled Control and IMF4 RNA samples were used to synthesize two SAGE libraries using the Long SAGE kit by Invitrogen.
2007-12-22 | E-GEOD-9344 | biostudies-arrayexpress
Project description:Unilateral once daily milking locally induces differential gene expression in both mammary tissue and milk epithelial cells revealing mammary remodeling
| PRJNA186614 | ENA