Cabergoline treatment at dry-off facilitated the remodelling and the lactoferrin immunoprotection of the mammary tissue in dairy cows

ObjectivesIn ruminants, the early phase of drying-off is a period of intense mammary gland involution that is due, in part, to dramatic decline prolactin (PRL) release. The speed at which the bovine mammary gland involutes following the abrupt cessation of lactation is also directly related to the risk of new intramammary infections. Thus, strategies to hasten involution following dry-off could have implications in preventing mastitis and optimizing mammary tissue regenerative processes.Materials and methodsTo assess the effect of prolactin inhibition by cabergoline on mammary gland involution, 14 Holstein dairy cows were injected with a single i.m. administration of 5.6 mg cabergoline (n=7) or placebo (n=7) within 4 hours after the last milking before the drying off at the day of drying-off (D0). Mammary secretion samples were collected using a teat-cannula once during lactation (D-6) and at D1, D2, D3, D4, D8 and D14 after the drying-off. The mammary secretion samples were used for lactoferrin and zymography analyses to detect the activity of enzymes such as MMP, matrix metalloproteinases involved in the remodelling of mammary tissue during involution. Mammary epithelial cells (MEC) were also purified from mammary secretions after centrifugation andimmunocytochemical binding in order to evaluate the MEC exfoliation. Mammary biopsy samples were collected one week before drying-off (D-6), at D1 and at D8 and used for lactoferrin immunochemistry and zymography analyses.ResultsThe activity of MMP9 increased after drying-off in mammary secretions (P < 0.001). Cabergoline increased the activity of MMP9 (1.7 fold, P < 0.05) in mammary secretions and MMP-2 in mammary tissue after drying-off (1.4 fold, P ≤ 0.01). MEC concentration progressively increased in mammary secretions after drying-off (P < 0.01). Cabergoline induced an increase in MEC concentration (P =0.04). Lactoferrin content progressively increased in mammary secretions during involution. The rise of lactoferrin content in mammary secretions was significant starting at D4 in the cabergoline treated cows (P ≤0.05) whereas it only happened at D8 in controls (P < 0.05). Overall, cabergoline treatment increased lactoferrin content of mammary secretions (P = 0.10). The total lactoferrin immunostaining in the mammary tissue increased after drying-off (P < 0.05). Compared with during lactation, this increase was observed at D1 and D8, respectively for cabergoline treated cows and control cows (P <0.05).ConclusionsOur results indicate that cabergoline treatment was efficient to enhance the extracellular matrix mammary remodeling, and the MEC exfoliation from the mammary epithelium and also hasten the udder immunoprotection by lactoferrin and therefore facilitates the drying-off

Cabergoline treatment at dry-off accelerated mammary involution as indicated by mammary secretion composition changes in dairy cows

In ruminants, the early phase of drying-off is a period of mammary gland involution that is marked by the cessation of prolactin (PRL) release. The speed at which the bovine mammary gland involutes following the abrupt cessation of lactation is directly related to the risk of new intramammary infections.ObjectivesOur aim was to assess the effect of PRL inhibition by cabergoline on the speed of the mammary gland involution, through analysis of the changes of mammary secretion composition.Materials and methodsFourteen Holstein dairy cows were injected with a single i.m. administration of 5.6 mg cabergoline (n=7) (Velactis ®, Ceva Sante Animale) or placebo (n=7) at the first day of dryingoff (D0). Mammary secretion samples were collected using a teat-cannula once during lactation (D-6) and at D1, D2, D3, D4, D8 and D14 after the drying-off. The mammary secretion samples were used for milk fat, lactose, true protein, alpha-lactalbumin and SCC analysis. Mammary biopsy samples were collected one week before drying-off (D-6), at D1 and at D8 and used for RNA extraction and RT-PCR analyses.ResultsAs expected, SCC progressively increased whereas lactose content decreased in mammary secretions after drying-off (P < 0.001). The increase in SCC was 2.4 fold higher in cabergoline treated cows than in control cows (P < 0.01). The decrease of lactose content in mammary secretions progressively decreased during involution and was associated with paralleled change in GLUT-1 mRNA level coding the main glucose transporter in the udder. These decreases were faster in cabergoline treated cows compared to controls with lower lactose content in cabergoline treated cows already by D1 than in controls (P < 0.05) and significant decrease in GLUT-1 mRNA levels at D1 and D8 respectively for cabergoline and control treatments compared to D-6 (P ≤ 0.05). Cabergoline treatment tended to increase fat content at D3 after drying-off (P < 0.10). No significant effects of cabergoline treatment were observed both in true protein and in alpha-lactalbumin contents in mammary secretions or in alphalactalbumin and kappa-casein mRNA levels in mammary tissues.ConclusionsThe changes in lactose, SCC and fat in mammary secretions and GLUT-1 mRNA level in the udder, indicate that cabergoline treatment was efficient to hasten the mammary gland involution without affecting milk protein synthesis in the mammary tissue. Cabergoline could facilitate dairy management at the time of dry-off

Cabergoline treatment at dry-off facilitated the remodelling and the lactoferrin immunoprotection of the mammary tissue in dairy cows

Objectives[br/] In ruminants, the early phase of drying-off is a period of intense mammary gland involution that is due, in part, to dramatic decline prolactin (PRL) release. The speed at which the bovine mammary gland involutes following the abrupt cessation of lactation is also directly related to the risk of new intramammary infections. Thus, strategies to hasten involution following dry-off could have implications in preventing mastitis and optimizing mammary tissue regenerative processes.[br/] Materials and methods[br/] To assess the effect of prolactin inhibition by cabergoline on mammary gland involution, 14 Holstein dairy cows were injected with a single i.m. administration of 5.6 mg cabergoline (n=7) or placebo (n=7) within 4 hours after the last milking before the drying off at the day of drying-off (D0). Mammary secretion samples were collected using a teat-cannula once during lactation (D-6) and at D1, D2, D3, D4, D8 and D14 after the drying-off. The mammary secretion samples were used for lactoferrin and zymography analyses to detect the activity of enzymes such as MMP, matrix metalloproteinases involved in the remodelling of mammary tissue during involution. Mammary epithelial cells (MEC) were also purified from mammary secretions after centrifugation and immunocytochemical binding in order to evaluate the MEC exfoliation. Mammary biopsy samples were collected one week before drying-off (D-6), at D1 and at D8 and used for lactoferrin immunochemistry and zymography analyses.[br/] Results[br/] The activity of MMP9 increased after drying-off in mammary secretions (P < 0.001). Cabergoline increased the activity of MMP9 (1.7 fold, P < 0.05) in mammary secretions and MMP-2 in mammary tissue after drying-off (1.4 fold, P ≤ 0.01). MEC concentration progressively increased in mammary secretions after drying-off (P < 0.01). Cabergoline induced an increase in MEC concentration (P =0.04). Lactoferrin content progressively increased in mammary secretions during involution. The rise of lactoferrin content in mammary secretions was significant starting at D4 in the cabergoline treated cows (P ≤0.05) whereas it only happened at D8 in controls (P < 0.05). Overall, cabergoline treatment increased lactoferrin content of mammary secretions (P = 0.10). The total lactoferrin immunostaining in the mammary tissue increased after drying-off (P < 0.05). Compared with during lactation, this increase was observed at D1 and D8, respectively for cabergoline treated cows and control cows (P <0.05).[br/] Conclusions[br/] Our results indicate that cabergoline treatment was efficient to enhance the extracellular matrix mammary remodeling, and the MEC exfoliation from the mammary epithelium and also hasten the udder immunoprotection by lactoferrin and therefore facilitates the drying-off

Inhibiting prolactin by cabergoline accelerates mammary gland remodeling during the early dry period in dairy cows

The inhibition of prolactin release using cabergoline, a dopamine agonist, is an effective strategy to accelerate the changes in mammary secretion composition after drying-off. The objective of this study was to determine how cabergoline may affect mammary tissue remodeling during early involution. Holstein dairy cows were treated with either a single i.m. administration of 5.6 mg of cabergoline (Velactis, Ceva Santé Animale, Libourne, France, n = 7) or placebo (n = 7) at the time of drying-off. Mammary biopsy samples were collected 1 wk before drying-off (d -6), after 30 h of milk accumulation (d 1), and again 8 d following drying-off (d 8) to determine changes in gene expression, lactoferrin content, and cell turnover. Blood and mammary secretion samples were collected at d -6 and again at d 1, 2, 3, 4, 8, and 14 following the abrupt cessation of lactation to evaluate indicators of blood-milk barrier integrity and other markers of mammary tissue remodeling. Cabergoline induced less SLC2A1, BAX, CAPN2, and IGFBP5 mRNA expression. In contrast, cabergoline did not modify changes in cell proliferation and apoptosis. Following the cessation of lactation, changes in mammary secretion composition (Na(+) and K(+)) and blood lactose concentrations were indicative of a loss in the blood-milk barrier function in both treatment groups. Cabergoline treatment affected only Na(+) and K(+) concentrations at d 1, suggesting a moderate increase in tight junction permeability. The increase in the activity of MMP9 and in mammary epithelial cell concentration in mammary secretions was greater in cabergoline-treated cows than in control cows, suggesting more mammary tissue remodeling. The increase in lactoferrin immunostaining in the mammary tissue occurred earlier for cabergoline-treated cows than for control cows, and was essentially localized in the stroma. Changes in some key markers of mammary involution suggest that cabergoline accelerates mammary gland remodeling. Thus, a single injection of cabergoline after the last milking would facilitate drying-off by enhancing mammary gland involution

Cabergoline treatment at dry-off accelerated mammary involution as indicated by mammary secretion composition changes in dairy cows

In ruminants, the early phase of drying-off is a period of mammary gland involution that is marked by the cessation of prolactin (PRL) release. The speed at which the bovine mammary gland involutes following the abrupt cessation of lactation is directly related to the risk of new intramammary infections.[br/] Objectives[br/] Our aim was to assess the effect of PRL inhibition by cabergoline on the speed of the mammary gland involution, through analysis of the changes of mammary secretion composition.[br/] Materials and methods[br/] Fourteen Holstein dairy cows were injected with a single i.m. administration of 5.6 mg cabergoline (n=7) (Velactis ®, Ceva Sante Animale) or placebo (n=7) at the first day of dryingoff (D0). Mammary secretion samples were collected using a teat-cannula once during lactation (D-6) and at D1, D2, D3, D4, D8 and D14 after the drying-off. The mammary secretion samples were used for milk fat, lactose, true protein, alpha-lactalbumin and SCC analysis. Mammary biopsy samples were collected one week before drying-off (D-6), at D1 and at D8 and used for RNA extraction and RT-PCR analyses.[br/] Results[br/] As expected, SCC progressively increased whereas lactose content decreased in mammary secretions after drying-off (P < 0.001). The increase in SCC was 2.4 fold higher in cabergoline treated cows than in control cows (P < 0.01). The decrease of lactose content in mammary secretions progressively decreased during involution and was associated with paralleled change in GLUT-1 mRNA level coding the main glucose transporter in the udder. These decreases were faster in cabergoline treated cows compared to controls with lower lactose content in cabergoline treated cows already by D1 than in controls (P < 0.05) and significant decrease in GLUT-1 mRNA levels at D1 and D8 respectively for cabergoline and control treatments compared to D-6 (P ≤ 0.05). Cabergoline treatment tended to increase fat content at D3 after drying-off (P < 0.10). No significant effects of cabergoline treatment were observed both in true protein and in alpha-lactalbumin contents in mammary secretions or in alphalactalbumin and kappa-casein mRNA levels in mammary tissues.[br/] Conclusions[br/] The changes in lactose, SCC and fat in mammary secretions and GLUT-1 mRNA level in the udder, indicate that cabergoline treatment was efficient to hasten the mammary gland involution without affecting milk protein synthesis in the mammary tissue. Cabergoline could facilitate dairy management at the time of dry-off

Efficacy of cabergoline in a double-blind randomized clinical trial on milk leakage reduction at drying-off and new intramammary infections across the dry period and postcalving

The abrupt cessation of milking at dry-off may induce milk leakage, which may increase the risk of new intramammary infections (IMI). This study assessed the efficacy of 1 i.m. injection of 5.6 mg of cabergoline (Velactis, Ceva Santé Animale, Libourne, France) at drying-off on milk leakage after dry-off and new IMI across the dry period and postcalving compared with a placebo (negative control) and an intramammary antibiotic treatment (positive control) under field conditions. The study was a double-blind, randomized, 3-arm, multicenter, clinical trial performed under Good Clinical Practice conditions. Data from 900 dairy cows of various breeds from 63 farms in France, Germany, and Hungary were analyzed. Only quarters with no bacterial growth at drying-off and a cow somatic cell count ≤200,000 cells/mL were included. Quarters infected with major or minor pathogens or cows with high somatic cell count at time of inclusion were excluded. Cows that qualified for the study were visited 7 times in total before and after drying-off and after calving. Presence (yes/no) of milk leakage was recorded on the day after dry-off. A new infected quarter (new IMI) was defined as one with a major pathogen present in any one of the 2 postcalving samples. Two mixed logistic regression models were fitted to the data to evaluate the efficacy of cabergoline in the reduction of milk leakage and new IMI. One i.m. injection of cabergoline at drying-off significantly reduced the incidence of milk leakage the day after dry-off compared with both placebo and antibiotic treatment. Cabergoline-treated cows significantly reduced the risk of new IMI by major pathogens across the dry period and postcalving by 21% when compared with placebo cows (20.5 vs. 26.0%, respectively). However, when milk leakage was added to the model, the significance of cabergoline was reduced. We interpreted this to show that milk leakage is an intervening variable between treatment with cabergoline and lower risk of new IMI. The antibiotic treatment significantly decreased the odds of new IMI compared with both cabergoline and placebo. However, because several countries are currently disallowing the preventive use of antibiotics at dry-off in noninfected quarters, the dry-off facilitator cabergoline may therefore be of particular value to reduce the risk of new IMI across the dry period

Efficacy of cabergoline in a double-blind randomized clinical trial on milk leakage reduction at drying-off and new intramammary infections across the dry period and postcalving

The abrupt cessation of milking at dry-off may induce milk leakage, which may increase the risk of new intramammary infections (IMI). This study assessed the efficacy of 1 i.m. injection of 5.6 mg of cabergoline (Velactis, Ceva Santé Animale, Libourne, France) at drying-off on milk leakage after dry-off and new IMI across the dry period and postcalving compared with a placebo (negative control) and an intramammary antibiotic treatment (positive control) under field conditions. The study was a double-blind, randomized, 3-arm, multicenter, clinical trial performed under Good Clinical Practice conditions. Data from 900 dairy cows of various breeds from 63 farms in France, Germany, and Hungary were analyzed. Only quarters with no bacterial growth at drying-off and a cow somatic cell count ≤200,000 cells/mL were included. Quarters infected with major or minor pathogens or cows with high somatic cell count at time of inclusion were excluded. Cows that qualified for the study were visited 7 times in total before and after drying-off and after calving. Presence (yes/no) of milk leakage was recorded on the day after dry-off. A new infected quarter (new IMI) was defined as one with a major pathogen present in any one of the 2 postcalving samples. Two mixed logistic regression models were fitted to the data to evaluate the efficacy of cabergoline in the reduction of milk leakage and new IMI. One i.m. injection of cabergoline at drying-off significantly reduced the incidence of milk leakage the day after dry-off compared with both placebo and antibiotic treatment. Cabergoline-treated cows significantly reduced the risk of new IMI by major pathogens across the dry period and postcalving by 21% when compared with placebo cows (20.5 vs. 26.0%, respectively). However, when milk leakage was added to the model, the significance of cabergoline was reduced. We interpreted this to show that milk leakage is an intervening variable between treatment with cabergoline and lower risk of new IMI. The antibiotic treatment significantly decreased the odds of new IMI compared with both cabergoline and placebo. However, because several countries are currently disallowing the preventive use of antibiotics at dry-off in noninfected quarters, the dry-off facilitator cabergoline may therefore be of particular value to reduce the risk of new IMI across the dry period

Incidence of milk leakage after dry-off in European dairy herds, related risk factors, and its role in new intramammary infections

The incidence of milk leakage (ML) after dry-off (DO) and related risk factors was studied in 1,175 dairy cows from 41 commercial herds in 8 European countries: Belgium, Czech Republic, Denmark, France, Germany, Italy, the Netherlands, and Spain. Milk leakage was assessed twice for 30 s each during 3 visits at 20 to 24 h, 30 to 34 h, and 48 to 52 h after DO. Information related to dry-cow management and udder health was collected at herd and cow level, including individual somatic cell count (ISCC) from test-day controls and occurrence of clinical mastitis cases from DO until 30 d in lactation. Mixed-effect logistic regression analyses were used to identify possible risk factors for ML and to study the association between ML and new intramammary infections. Intramammary infections were defined as clinical mastitis cases during the dry period and in the first 30 d in lactation or a rise in ISCC from before to after the dry period (threshold: 200,000 cells/mL) or both. Milk leakage was observed in 24.5% of the cows between 20 and 52 h after DO, where the herd incidence varied between 0.0 and 77.8%. The reduction in number of milkings in the weeks before DO had statistically significant effect on the ML incidence. When the milking frequency was reduced from 3 times/d to 2 or maintained at twice a day, cows had 11 (95% CI = 3.43–35.46) or 9 (95% CI = 1.85–48.22) times higher odds of leaking milk, respectively, compared with cows where the milking frequency was reduced from twice to once a day. Also, the milk production 24 h before DO was associated with ML incidence. Hence, cows with a milk production between 13 and 21 L or above 21 L had 2.3 (95% CI = 1.48–3.53) and 3.1 (95% CI = 1.79–5.3) times higher odds of leaking milk, respectively, compared with cows with a milk production below 13 L. A higher ML incidence was present in the group of cows with an average ISCC in the last 3 mo before DO ≥200,000 cells/mL (odds ratio = 1.7; 95% CI = 1.13–2.41) compared with cows with an average ISC

Incidence of milk leakage after dry-off in European dairy herds, related risk factors, and its role in new intramammary infections

The incidence of milk leakage (ML) after dry-off (DO) and related risk factors was studied in 1,175 dairy cows from 41 commercial herds in 8 European countries: Belgium, Czech Republic, Denmark, France, Germany, Italy, the Netherlands, and Spain. Milk leakage was assessed twice for 30 s each during 3 visits at 20 to 24 h, 30 to 34 h, and 48 to 52 h after DO. Information related to dry-cow management and udder health was collected at herd and cow level, including individual somatic cell count (ISCC) from test-day controls and occurrence of clinical mastitis cases from DO until 30 d in lactation. Mixed-effect logistic regression analyses were used to identify possible risk factors for ML and to study the association between ML and new intramammary infections. Intramammary infections were defined as clinical mastitis cases during the dry period and in the first 30 d in lactation or a rise in ISCC from before to after the dry period (threshold: 200,000 cells/mL) or both. Milk leakage was observed in 24.5% of the cows between 20 and 52 h after DO, where the herd incidence varied between 0.0 and 77.8%. The reduction in number of milkings in the weeks before DO had statistically significant effect on the ML incidence. When the milking frequency was reduced from 3 times/d to 2 or maintained at twice a day, cows had 11 (95% CI = 3.43–35.46) or 9 (95% CI = 1.85–48.22) times higher odds of leaking milk, respectively, compared with cows where the milking frequency was reduced from twice to once a day. Also, the milk production 24 h before DO was associated with ML incidence. Hence, cows with a milk production between 13 and 21 L or above 21 L had 2.3 (95% CI = 1.48–3.53) and 3.1 (95% CI = 1.79–5.3) times higher odds of leaking milk, respectively, compared with cows with a milk production below 13 L. A higher ML incidence was present in the group of cows with an average ISCC in the last 3 mo before DO ≥200,000 cells/mL (odds ratio = 1.7; 95% CI = 1.13–2.41) compared with cows with an average ISC