Effect of Milking Frequency on Mammary Functioning and Shape of the Lactation Curve

Stelwagen, K.

doi:10.3168/jds.s0022-0302(01)70219-6

Cited by 120 publications

(137 citation statements)

References 73 publications

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“…If colchicine (which is known to destructure the cytoskeleton) was injected via the teat canal, similar effects were observed [36]. According to Stelwagen [37], the migration of secretory vesicles could be disturbed by an accumulation of milk in the mammary alveoli because of modifications to the cytoskeleton orchestrated by the opening of tight junctions.…”

Section: Metabolic and Secretion Activitiesmentioning

confidence: 82%

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

et al. 2006

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-The aim of this review is to better understand the regulation of milk yield in response to once-daily milking and feed restriction. Glucose is the principal precursor for the synthesis of lactose (a major osmotic agent in milk), and participates in determining the milk volume produced. When applying these two breeding factors, reductions in milk yield are associated with a reduction in milk lactose yield and in the arterial flow of glucose, due to a decrease in the mammary blood flow. The ability of the udder to extract glucose is altered with once-daily milking but not necessarily with feed restriction. Lactose synthesis is down-regulated in response to once-daily milking and feed restriction but the percentage of the extracted glucose which is converted into lactose is differently affected in response to treatments. No marked change is observed with once daily milking whereas this would be increased with feed restriction and in contrast, depressed with fasting. milk yield / glucose / mammary gland / uptake / metabolic fate / ruminants

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Section: Metabolic and Secretion Activitiesmentioning

confidence: 82%

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

et al. 2006

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“…To our knowledge, there are no data describing the early regulation of MEC dynamics and activity during the first days of ODM application. One of the putative regulatory mechanisms is the disruption of mammary epithelium integrity (Stelwagen, 2001). Disruption of mammary tight junctions is associated with a decrease in milk yield in different situations such as psychological stress (Stelwagen et al, 2000), mastitis (Leitner et al, 2004) and longer milking intervals (Stelwagen et al, 1994;Delamaire and Guinard-Flament, 2006).…”

Section: Introductionmentioning

confidence: 99%

The decrease in milk yield during once daily milking is due to regulation of synthetic activity rather than apoptosis of mammary epithelial cells in goats

Chedly

Lacasse

Marnet

et al. 2013

Animal

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Once daily milking (ODM) is a management practice that can improve working conditions and reduce production costs in dairy farming compared with twice daily milking (TDM). However, ODM is associated with a decrease in milk yield. Previous research indicated that disruption of tight junctions in the mammary gland may be one of the regulatory factors involved in the milk yield decrease observed during ODM. The aim of this study was to investigate the involvement of mammary epithelium disruption in the regulation of the activity and dynamics of mammary epithelial cells (MEC) during 5 weeks of ODM in goats. Twelve alpine goats (producing 3.67 ± 0.64 kg/day and 47 ± 1.6 days in milk) were assigned to two groups that were milked once or twice a day during 5 weeks and then switched back to TDM. Mammary biopsies were collected before and on days 2 and 16 of both ODM and TDM switchback periods. Milk purified epithelial cells were collected before and on days 1, 7, 21 and 28 during ODM as well on days 1 and 7 of the TDM switchback period. The mRNA levels of genes involved in the regulation of synthetic activity and apoptosis were analysed by RT-PCR in milk MEC and mammary biopsies. ODM decreased yields of milk (−23%), lactose (−23%) and casein (−16%). Lactose synthesis was regulated at the transcriptional level by downregulation of α-lactalbumin mRNA levels in both biopsy samples (−30%) and milk MEC (−74%). TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling) staining of mammary gland biopsies did not show any increase in cell apoptosis after 2 and 16 days of ODM (0.8% and 1%, respectively) despite upregulation of Bax mRNA levels in milk MEC. This suggests that the decrease in milk yield observed during ODM is attributable to a decrease in synthetic activity rather than to induction of MEC cell death. ODM induced the disruption of tight junctions in the mammary gland only on the first day of the treatment as indicated by increased blood lactose concentration. This indicates that the decrease in MEC activity observed over the 5 weeks of ODM was not due to disruption of the mammary gland tight junctions. There was no carryover effect of 5 weeks of ODM on milk production. Therefore, it appears that the decrease in milk yield that occurs during ODM in goats is due to regulation of synthetic activity rather than to apoptosis of MEC.

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“…The loss of milk yield varies from 15% to 30% in small ruminants (Nudda et al, 2002;Marnet and Komara, 2008). Milk yield declines when the number of mammary epithelial cells (MECs) and/or their synthetic activity decreases (Stelwagen, 2001;Capuco et al, 2003). However, very few studies have investigated the effects of ODM on the cellular regulation pathways related to the observed loss of milk yield.…”

Section: Introductionmentioning

confidence: 99%

Use of milk epithelial cells to study regulation of cell activity and apoptosis during once-daily milking in goats

Chedly

Lacasse

Marnet

et al. 2011

Animal

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Generally, once-daily milking (ODM) decreases milk yield. This effect may be the consequence of a decrease in mammary epithelial cell (MEC) activity or a reduction in their number. The aim of this study was to determine the effect of ODM on the synthetic activity and rate of apoptosis of MEC using a non-invasive method. Eight Alpine goats were subjected to ODM or twice-daily milking for two 5-week periods. MECs were purified by centrifugation and immunocytochemical binding in milk after 1 and 5 weeks of each period. mRNA levels of some proteins involved in lactose and milk protein synthesis and in apoptosis were evaluated using real-time PCR. Isolation of MEC from milk was a useful method to investigate transcriptional regulation in a timeline study. ODM induced greater decreases in milk, lactose and protein yields after 1 week than after 5 weeks. This suggests an adaptation of the mammary gland to ODM, which reduces the inhibitory effect of this practice. Reductions in milk component yields were associated with lower a-lactalbumin transcripts, suggesting a transcriptional decrease of lactose synthesis during ODM. Glucose transporter GLUT1 transcripts were downregulated under ODM, suggesting that lactose precursor uptake by MEC might be involved in the regulation of lactose synthesis. k-Casein mRNA levels tended to be lower during ODM. ODM increased levels of the pro-apoptotic transcript Bax after both 1 and 5 weeks, but no variation was observed in the Bax/Bcl-2 ratio. ODM affected cell synthetic activity through transcriptional regulation and may have induced apoptosis. The reduction of the negative effect of ODM on milk yield suggests that Alpine goats are able to adapt to ODM. Further studies are needed to investigate the effect of ODM on MEC turnover.

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Effect of Milking Frequency on Mammary Functioning and Shape of the Lactation Curve

Cited by 120 publications

References 73 publications

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

Changes in mammary uptake and metabolic fate of glucose with once-daily milking and feed restriction in dairy cows

The decrease in milk yield during once daily milking is due to regulation of synthetic activity rather than apoptosis of mammary epithelial cells in goats

Use of milk epithelial cells to study regulation of cell activity and apoptosis during once-daily milking in goats

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