The association between teat shape and bimodal milk ejection in Holstein dairy cows.

Our objectives were to investigate the association of teat shape with (1) bimodality, (2) incremental milk flow rates (average flow rates during the first 15 s, 15-30 s, 30-60 s, and 60-120 s of milking), and (3) peak milk flow rate in Holstein dairy cows milked 3 times/d. In this prospective cohort study, we analyzed 220,928 milking observations that were collected from 2,520 cows from a single dairy herd over a period of 31 d. Teat shape was visually assessed and classified into 1 of 4 categories as follows: (1) triangular barrel and pointed teat end (TP), (2) square barrel and round teat end (SR), (3) square barrel, round teat end, and flat in the area of the teat orifice (SRF), and (4) square barrel and flat teat end (SF). Individual cow-level milk flow rates were obtained using electronic on-farm milk meters. We considered bimodality to be present if any of the incremental milk flow rates (flow rates during 15-30 s, 30-60 s, or 60-120 s) were lower than any of the previous rates (flow rates during the first 15 s, 15-30 s, or 30-60 s). The frequency distribution of cows with different teat shapes was as follows: TP, 96 (3.8%); SR, 1,751 (69.5%); SRF, 617 (24.5%); and SF, 56 (2.2%). A generalized linear mixed model revealed differences in the odds of bimodality among cows with different teat shapes. Compared with cows in category SR, the odds (95% CI) of bimodality of cows in other categories were as follows: TP, 0.68 (0.48-0.97); SF, 1.96 (1.21-3.19); and SRF, 1.46 (1.23-1.72). General linear mixed models indicated an association between teat shape and all incremental milk flow rates, with higher milk flow rates being present for cows with teat shapes in the SRF and SF categories. The general linear mixed model for the dependent variable peak milk flow rate indicated an association between teat shape and peak milk flow rate. Least squares means and 95% CI were 5.1 (4.9-5.3) kg/min for TP, 5.8 (5.5-6.1) kg/min for SF, 5.6 (5.5-5.7) for SRF, and 5.3 (5.3-5.4) for SR, respectively. We conclude that in this study cohort, bimodality is more likely to occur in cows with flat teat ends compared with those with a round teat ends. We attribute this relationship to the difference in milking speed across cows with different teat shapes. Teat shape may serve as a useful phenotype to identify cows that are more likely to exhibit bimodality. Because our study population was unique, future studies considering different circumstances such as breed, milking system, and milking routine are needed before results can be extrapolated.

Dysphoric milk ejection reflex - call for future trials.

Dysphoric milk ejection reflex is a condition that causes an abrupt emotional downturn during the initial moments of milk ejection in a breastfeeding mother. Depression, anxiety, hopelessness, anger, irritability, homesickness, and stomach hollowness are all possible symptoms. The exact cause of D-MER remains unknown. However, it is proposed that it is caused by an alteration in oxytocin signaling response where secretion of oxytocin upregulates the stress response instead of its downregulation. Activation of the defensive response of the mother by oxytocin during breastfeeding, disruption in dopamine levels, and activation of vasopressin-regulated pathways are other probable causes. Due to a lack of awareness, this phenomenon is easily misdiagnosed as postpartum depression and aversion by many healthcare professionals. Its prevalence in various populations of the world remains unknown due to the lack of research studies conducted in these populations. While no medically approved therapeutic strategy is available, supportive techniques such as maintaining a healthy diet, mental distraction, relaxation methods, and increasing skin-to-skin contact can help alleviate dysphoria during breastfeeding. However, due to a lack of D-MER research, specific challenges exist regarding early withdrawal from breastfeeding and women's help-seeking attitude toward perinatal mental health.

The interplay of continuous milk ejection and milking system with and without prestimulation at different vacuum settings.

Efficient machine milking requires an optimal interaction of alveolar milk ejection in the udder and milk removal by the milking machine. The aim of the present study was to test whether the equilibrium between continuous milk ejection and milk removal can also be maintained at very fast milking through a particularly high vacuum. Eight Holstein dairy cows were milked at 42, 52, or 60 kPa, with (PS) or without (nPS) prestimulation. Each of the 6 treatments was conducted at 2 afternoon milkings in each animal. The prestimulation lasted 40 s and consisted of forestripping and teat cleaning. The cluster attachment followed after a 20-s latency period. Throughout each milking, B-mode ultrasound videos of the gland cistern of 1 front quarter as well as milk flow and claw vacuum curves were recorded. Total milk yield was neither affected by nPS or PS nor by the vacuum level. Milk removed within the first minute and the first 2 min of milking and average milk flow were higher, and the duration of incline and time until peak milk flow were shorter at PS than at nPS milkings at all vacuum levels. Machine-on time was shorter at PS than at nPS milkings, although only at 42 and 52 kPa vacuum, obviously caused by the high percentage of bimodalities occurring in nPS milkings (17% bimodalities in PS vs. 92% bimodalities in nPS milkings). The frequency of bimodalities was higher at high than at low vacuum both in PS and nPS milkings. Peak flow rate and average milk flow were both higher at higher vacuum levels. The duration of milk flow plateau was shorter at 60 kPa than at 42 kPa milkings. At the highest vacuum (60 kPa), the shorter plateau phase indicated a declining milk ejection rate toward the end of the plateau phase, and milk ejection could no longer keep up with the fast milk removal; hence, a higher milking efficiency at a higher vacuum level could only be achieved as long as the gland cistern remained sufficiently filled by the continuous milk ejection. The ultrasound imaging confirmed this finding as the duration of cisternal area plateau in the recorded front quarter was shorter at high than at low vacuum. Thus, the highest vacuum of 60 kPa did not cause a shorter machine-on time than 52 kPa. In conclusion, milking at a very high vacuum can increase milking efficiency compared with a low vacuum. However, a vacuum reduction at the start and toward the end of milking is required to prevent overmilking if milking is performed at a very high vacuum.

Risk factors for delayed milk ejection in Holstein dairy cows milked 3 times per day.

Delayed milk ejection, manifested most often as bimodal milk flow, occurs when the cisternal milk fraction is removed before the alveolar milk reaches the gland cistern. It is thought to be a consequence of not meeting cows' physiological needs, due to insufficient premilking teat stimulation, inadequate timing of milking unit attachment, or both. It has been associated with decreased milking efficiency, reduced milk yield, and impaired teat and udder health. Traditionally, portable electronic milk meters have been used to assess the presence of delayed milk ejection in dairy cows. By contrast, incremental milk flow rates from on-farm milk meters and their suitability as a measure to assess delayed milk ejection have not been studied by rigorous methods. The objectives were (1) to describe a protocol for identification of cows with chronically delayed milk ejection (CDME) and (2) to investigate risk factors for CDME using incremental milk flow rates obtained from automated on-farm milk meters. In a retrospective case control study, milk flow data from a 4,300-cow dairy with a thrice-daily milking schedule were obtained over a 1-wk period. Incremental milk flow rates (0-15 s, 15-30 s, 30-60 s, and 60-120 s) were used to identify cows with delayed milk ejection. Cases of CDME were defined as presence of delayed milk ejection at all 21 milking observations. Cows that had no delayed milk ejection at any of the same 21 milking observations were included as controls. A total of 171 cases and 393 controls were included in the study based on these criteria. A logistic regression model was used to evaluate associations of the following risk factors with CDME: parity (1, 2, ≥3), stage of lactation (<100, 101-200, >200 DIM), presence of a nonlactating quarter, milk somatic cell count, average daily milk production, and health and management events. Parity and CDME were associated such that compared with cows in their third or greater lactation, the odds (95% confidence intervals, 95% CI) of CDME were 1.27 (0.71-2.25) for cows in their first and 4.77 (2.47-9.22) for animals in their second lactation. The odds of CDME increased with increasing stage of lactation, with an odds ratio of 0.20 (0.11-0.36) for early and 0.28 (0.15-0.52) for mid-lactation animals, respectively, compared with late lactation cows. A 1-kg increase in average daily milk production was associated with decreased odds of CDME [odds ratio (95% CI): 0.89 (0.87-0.92)]. A lameness event during the study period increased the odds of CDME [odds ratio (95% CI): 8.04 (1.20-53.83)], as did a vaccination event 1 wk before the study period [odds ratio (95% CI): 4.07 (0.99-16.71)]. This study confirmed associations between CDME and previously reported risk factors and identified several previously less rigorously investigated health and management events that could be associated with CDME. Incremental milk flow rates from individual cows serve as an automated tool to evaluate milk flow dynamics. This information could be used to improve individual premilking udder preparation to meet the animal's physiological requirements, improve teat and udder health, and enhance parlor efficiency.

Oxytocin and cortisol release during suckling, hand-milking and machine milking in camels.

This research paper addresses the hypothesis that oxytocin (OT) could be released during suckling and during milking with and without the presence of a calf and that this release could be regulated by maternal behaviour. Plasma concentration patterns of OT and cortisol (CORT) were measured in six Tunisian dromedary camels during 2 suckling episodes, 2 manual milking episodes with calves beside the mother and 2 machine milking episodes without calves present. Various patterns of OT release were observed between each camel including specific two peak release patterns. Higher plasma OT concentrations were found during the suckling and hand-milking episodes with simultaneous suckling of calves, than during the machine milking episodes without calves. Exclusive mechanical milking episodes also evoked significant mean OT release, although greatly reduced compared to suckling and hand milking. The low basal levels and classical CORT release patterns suggested non-stressful management practices were used and there were very limited differences in udder stimulation between managements. The OT release induced by exclusive suckling and suckling together with hand-milking gives a reference point for what a good milk ejection stimulation is in camels. The important and specific reduction of OT release during machine milking without the calf present could be a physiological consequence of the maternal behaviour (selectivity for the own young) and to a lesser extent explained by a lower stimulation by machine milking.

Detection of Milk Ejection Using Bioimpedance Spectroscopy in Lactating Women during Milk Expression Using an Electric Breast Pump.

Milk ejection is essential for effective milk removal during breastfeeding and pumping, and for continued milk synthesis. Many women are unable to accurately sense milk ejection to determine whether their infant is receiving milk or, when pumping, to switch the pump to a more effective expression pattern. To determine if changes in bioimpedance parameters are associated with milk ejection in the lactating breast during pumping. 30 lactating women participated in 2 pumping sessions within 2 weeks of each other. During pumping the breasts were monitored with bioimpedance spectroscopy (on either the pumped or the non- pumped breast), and milk flow rate and volume were measured simultaneously. All mothers completed 24-h milk productions. Linear mixed effects models were used to determine associations between milk flow rate and bioimpedance changes. Changes in bioimpedance parameters were greater at the first milk ejection when measured on the pumped breast (median (IQR): R zero: -7 (-17, -4,) % (n = 30); R infinity: -8 (-20, -2) % (n = 29); membrane capacitance: -24 (-59, -7) % (n = 27). Changes in bioimpedance detected in the non-pumped breast were lower at the first milk ejection, R zero: -3 (-8, -2) % (n = 25); R infinity: -5 (-8, -2) % (n = 23); membrane capacitance: -9 (-17, 15) % (n = 24). Smaller less consistent decreases in the bioimpedance characteristics were detected at the second milk ejection in both breasts. Bioimpedance parameters showed a consistent decrease associated with the first milk ejection when electrodes were placed on the pumped breast. Smaller decreases were observed when the non-pumped breast was monitored for the first and second milk ejection. There was wide variation in the magnitude of changes observed, and hence further development of the methodology is needed to ensure reliability.

Herd-level variables associated with premilking stimulation time in Michigan dairy herds.

The objective of this study was to determine the herd-level variables that were associated with total stimulation time during the premilking routine in 64 Michigan dairy herds. The mean herd size was 452 cows (range = 59 to 2,771 cows). For each herd, surveys were administered to producers to gather mastitis management practices and attitudes. Additionally, milking protocols were observed and milk flow dynamics were measured by use of digital vacuum recorders. Backward multivariate regression analysis was used to determine which of 47 herd-level milking and management variables were associated with mean total stimulation time. Mean total stimulation time was 14.2 s (range = 2.4-40.8 s) and was positively associated with increasing latency period (time interval between first stimulation and cluster attachment). Total stimulation time was negatively associated with greater herd size and number of visits to each cow in the premilking routine. In summary, increased stimulation time is more likely in herds that foster a lower sense of urgency of cow throughput during milking, as evidenced by a positive association with longer latency periods and fewer preparation visits per cow. Tactile stimulation is critical for efficient milk ejection; if inadequate, cows are at greater risk of delayed milk ejection and bimodal milk flow, which in turn has been associated with teat congestion and reduced milk flow. This study offers insight as to some of the herd factors that may be limiting adequate tactile stimulation.

Herd-level variables associated with delayed milk ejection in Michigan dairy herds.

The objective of this study was to determine which herd-level variables were associated with delayed milk ejection (bimodal milk let-down) in 64 Michigan dairy herds. Median herd size was 294 cows (range 59 to 2,771 cows). For each herd, milking protocols were observed and milk flow dynamics were estimated by use of digital vacuum recorders. Surveys were also administered to the producers to measure mastitis management practices and attitudes. Milk flow dynamics were recorded for a total of 3,824 cow milkings, with a mean of 60 milkings per herd (range of 11 to 154). Backward multivariable analysis was used to determine which of the 47 herd-level milking and management variables were associated with delayed milk ejection (cows with milk let-down periods between milking cluster attachment and the incline phase of milk flow of >30 s). Delayed milk ejection occurred in an average of 25% of the cows in each herd (range 0 to 75%). A multivariable model found that the proportion of cows in a herd with delayed milk ejection was negatively associated with mean total time of tactile stimulation during premilking routines and positively associated with herd size.

Technical note: Reduced pulsation chamber vacuum at normal pulsation rate and ratio provides adequate prestimulation to induce oxytocin release and milk ejection while simultaneous milk flow is prevented.

In the present study we investigated the milking characteristics and the oxytocin release in dairy cows milked after either manual prestimulation or a premilking period with pulsating liners at normal pulsation rate (60) and ratio (60:40) while the pulsation chamber vacuum (PCV) was reduced to 20 kPa to prevent the opening of the liners. During the milking trial with 8 cows the PCV reduction was started either before attachment (PCV-1) or immediately after attachment (PCV-2) of the teat cups. Milk yields, total milking times, average milk flows, peak flow rates, the duration of milk flow plateaus, and the duration of milk flow declines did not differ among the 3 treatments. Only the time to reach peak milk flow was prolonged when the vacuum reduction was started after teat cup attachment (PCV-2). In this treatment, milk flow >200 g/min already occurred during the premilking period, resulting in bimodal milk flow curves. In 5 of the 8 cows, plasma oxytocin (OT) concentrations were measured from -2 min before the start of milking until 3 min of milking to compare the OT release in response to manual prestimulation and during PCV-1. In both treatments, OT increased similarly and remained elevated until the end of measurements. Consequently, the areas under the curve of OT concentrations did not differ between treatments. In conclusion, milking performance is similar if milking is performed after manual prestimulation or after normal pulsation at reduced PCV. To prevent milk flow during the prestimulation period, it is of crucial importance to start the reduction of the PCV before cluster attachment.

Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.

The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece chamber vacuum on teat-end congestion and resultant decreases in CA.

Review of present knowledge on machine milking and intensive milk production in dromedary camels and future challenges.

The camel dairy industry has gone through major development in the last decade. The world's first large-scale camel dairy farm was established 10 years ago in Dubai, United Arab Emirates, and since then, several commercial and scientific projects have been started, and more studies have been published demonstrating increasing interest in camel milk. The aims of this paper are to summarize relevant published data on factors influencing milk production under intensive management, compare those with our own observations obtained from Emirates Industry for Camel Milk and Products (EICMP), and highlight areas of research that are indispensable for further development. As in other species, the most important factors influencing milk yield are genetic and individual variation, age, parity, stage of lactation, nutrition, management, season, photoperiod, etc. However, the precise role of the various factors has not been thoroughly studied in camels and based on our understanding of the basic physiological processes, endocrine control is minimal. In addition, machine milking of dromedaries is still at early stage and requires research for improvement of the technology and defining factors affecting and improving milk ejection. The role of environment (like photoperiod, nutrition) should also be investigated as there is significant annual variation both in milk quantity and quality that might influence the processing characteristics of raw camel milk. The large pool of animals and thoroughly recorded data at EICMP provide an excellent opportunity for increasing milk production and improving milk quality using various methods, like feeding, management, reproduction, selection, and breeding.

Milk ejection patterns: an intra- individual comparison of breastfeeding and pumping.

BACKGROUND: Milk ejection is a transient episode critical to milk removal and women typically have multiple milk ejections during breastfeeding and pumping. Recently it was found that milk ejection characteristics such as number of milk ejections and periodicity were consistent throughout 12 months of lactation in women who expressed their milk with an electric breast pump. It is not known whether the stimulation of an infant at the breast influences milk ejection patterns or whether this is a programmed event. The aim of this study was to compare milk ejection patterns during breastfeeding and expressing milk with an electric pump within mothers. METHODS: Twelve lactating mothers with normal milk production (502-1356 mL) had milk ejection recorded by measuring the diameter of a major milk duct with ultrasound imaging throughout an entire breastfeed and a 15-min pumping session. Scans were analysed for timing, duration of duct dilation and maximum duct diameter. RESULTS: The initial milk ejection defined as the first increase in duct diameter was observed earlier during breastfeeding than during two phase pumping sessions but was not statistically significant (p = .057). There were no significant differences between the duration of the first or second milk ejection for mothers when breastfeeding or pumping at their maximum comfortable vacuum (p = .18; p = .99). The times taken to reach the peak duct diameter, or the first half of the milk ejection were also not found to be significantly different between breastfeeding and pumping. CONCLUSION: This study suggests that milk ejection patterns remain consistent within individual mothers regardless of whether the mother is breastfeeding or expressing milk indicating a likelihood of the process either being programmed or innate to the individual.

Changes in milk L-lactate, lactate dehydrogenase, serum albumin, and IgG during milk ejection and their association with somatic cell count.

In both conventional and automatic milking systems (AMS), sensitive and reliable mastitis detection is important for profitable milk production. Mastitis detection parameters must be able to detect mastitis when the somatic cell count (SCC) is only slightly elevated. Owing to the pre-milking teat cleaning process in AMS, sampling cannot take place before the occurrence of alveolar milk ejection and importantly, this can affect the ability of parameters to detect mastitis. The aim of the present study was to examine the effect of alveolar milk ejection on L-lactate, lactate dehydrogenase (LDH), serum albumin (SA) and immunoglobulin G (IgG) compared with SCC, a commonly used indicator of mastitis. In this experiment, milk samples were collected every 20 s from one quarter during a 120-s manual teat stimulation in ten cows. Samples were analysed for SCC, L-lactate, LDH, SA and IgG. Quarters were grouped by low (<5.0 log10 cells/ml), mid (5.0-5.7 log10 cells/ml), and high (>5.7 log10 cells/ml) SCC using the sample at t=0 s. Neither L-lactate nor LDH could statistically differentiate between low and mid-SCC quarters, but there were a significant difference in levels between the high-SCC quarters and low and mid-SCC quarters. SA could not differentiate between the low and mid-SCC quarters, but the SA levels for the high SCC quarters remained statistically different compared with low and mid-SCC quarters throughout the experiment. IgG could statistically differentiate between low and mid-SCC, although the high-SCC quarters were not statistically different from the mid-SCC quarters after 60 s. In the high-SCC quarters, a decrease was shown in all parameters during milk ejection, after t=60 s. In conclusion, alveolar milk ejection reduces the effectiveness of detection parameters when compared with SCC. With the exception of IgG, the ability of other tested parameters was not satisfactory to differentiate between quarters with low to mid-SCC levels.

First description of milk flow traits in Tunisian dairy dromedary camels under an intensive farming system.

In order to evaluate milking ability in dromedary camels, 124 milk flow curves were registered during morning milking of 20 dairy Maghrebi dromedary camels. Animals were in lactations 1-8, were 6-19 years old and were 4-15 months of their current lactation. Milk flow curves were recorded using an electronic milk flow meter (Lactocorder®). Milk flow curves were classified in three typical patterns: type 1 represents curves with one high and short peak of milk flow; type 2 represents curves with a moderate mean milk flow rate during a large plateau phase; and type 3 represents curves with lower mean milk flow rate and a relatively longer milking duration. The ratio of the different milk flow patterns in the population evaluated was 40:38:22% for types 1, 2 and 3, respectively. The highest milk yield per milking, average and peak milk flow were observed in camels with type 1 curves (4·24 kg, 1·49 and 3·54 kg/min, respectively) followed by type 2 animals (3·30 kg, 1·12 and 2·12 kg/min, respectively) and lastly type 3 curves (2·34 kg, 0·65 and 1·23 kg/min, respectively). This study confirmed that a major proportion of dromedary camels have a suitable machine milking ability. Nevertheless, our results suggest that pre-stimulation and improving the milking process may improve milking efficiency and guarantee a more complete and rapid emptying of the udder.

Effects of a latency period between pre-stimulation and teat cup attachment and periodic vacuum reduction on milking characteristics and teat condition in dairy cows.

The goal of the present study was to examine the suitability of a short pre-stimulation (P) for 15 s followed by a latency period (L) of 30 s before cluster attachment for machine milking. In addition we tested the effect of a periodic reduction of the vacuum under the teat (VR) during the massage phase from 43 kPa to 12-15 kPa on milking characteristics and teat tissue condition. The study was carried out in 9 cows in a cross-over design. Animals were milked twice daily, and each of the 4 treatment combinations was used for six subsequent milkings (P+L vs. continuous P, and standard pulsation vs. VR, respectively). Milk flow was recorded during all experimental milkings. Longitudinal ultrasound cross sections of the teat were performed by B-mode ultrasound after the last milking of each treatment at 0, 5, and 15 min after the end of milking, respectively. None of the evaluated milking characteristics (total milk yield, main milking time, peak flow rate, average milk flow) differed between treatments. Teat measures as obtained by ultrasound cross sections showed no significant difference if individual treatments were compared at the three time points individually. However, teat wall thickness (TWT) tended to be smaller in VR vs. non-VR treatments at 5 min after milking (P=0·05). In conclusion, teat preparation consisting of a short stimulation followed by a latency period represents a similarly efficient pre-stimulation as a continuous pre-stimulation. VR seems to reduce the load on the teat tissue during milking and thus reduces the development of oedema and hence a less pronounced increase of TWT while milking characteristics are similar with or without VR.

Dysphoric Milk Ejection Reflex in Human Lactation: An Integrative Literature Review.

BACKGROUND: Dysphoric Milk Ejection Reflex is an understudied condition of lactation involving emotional dysregulation during letdown or milk ejection. Affected individuals may experience transient feelings of helplessness, melancholy, and general unhappiness. RESEARCH AIM: To evaluate the scope of published literature on Dysphoric Milk Ejection Reflex. METHOD: Whittemore and Knafl's methodology guided this integrative review. Five databases were searched for primary research, summaries, and editorials on Dysphoric Milk Ejection Reflex in lactating individuals. Literature searched also included websites, pamphlets, and conference proceedings via Google and Google Scholar. A total of 11 articles, from five different countries, met inclusion criteria for review. RESULTS: Studies on Dysphoric Milk Ejection Reflex and negative emotional sensations during lactation were synthesized under five conceptual umbrellas: (1) Experiences, Sensations, and Symptom Management; (2) Biological Underpinnings; (3) Influence on Maternal Role and Breastfeeding Self-Efficacy; (4) Support, Understanding, and Awareness; and (5) Reduction and Cessation of Breastfeeding. CONCLUSION: Dysphoric Milk Ejection Reflex is a neurobiological condition characterized by low mood and negative feelings during milk ejection throughout lactation. Dysphoric Milk Ejection Reflex is linked to maternal psychological distress and breastfeeding discontinuation. Priority areas for future research include biological origins and interventions aimed at prevention, symptom control, and greater awareness of the condition on a more international scope.

Dysphoric milk ejection reflex among Japanese mothers: a self-administered survey.

BACKGROUND: The dysphoric milk ejection reflex (D-MER) is a reflex that causes temporary discomfort during milk ejection. D-MER develops due to the effects of hormones involved in lactation, and it has been reported that it is a physiological symptom different from postpartum depression, but the actual situation is unknown in Japan. METHODS: This study was conducted using a self-administered, anonymous survey of mothers of children who had undergone health checkups at three years of age at five health centers in Kagoshima city and aimed to clarify the reality and perceptions of mothers regarding D-MER. The survey period was from May to September, 2022. The questionnaires were distributed to 389 mothers, and 216 (55.5% recovery rate) responses were received, of which 202 (valid response rate 93.5%) were included in the analysis. RESULTS: Regarding the experience of D-MER, 202 mothers in the study population had given birth to a total of 403 children and experienced D-MER when breastfeeding 62 children (15.4%). Of the 202 mothers included in the analysis, 47 (23.3%) answered that they had experienced D-MER with at least one child while breastfeeding. Sixty-six mothers (32.7%) knew about D-MER. Compared to those who had not experienced D-MER, those who had experienced D-MER had significantly higher scores on the items related to having had trouble breastfeeding (odds ratio (OR]: 3.78; 95% confidence interval (CI]: 1.57, 9.09) and knowing about D-MER (OR 2.41; 95% CI 1.20, 4.84). Regarding symptoms, irritability (n = 24, 51.1%), anxiety (n = 22, 46.8%), and sadness (n = 18, 38.3%) ranked high. Coping strategies included distraction, focusing on the child, and, in some cases, cessation of breastfeeding. Thirty mothers (63.8%) answered that they did not consult anyone, citing reasons such as a belief that no one would be likely to understand their symptoms, and that they could not sufficiently explain their symptoms. CONCLUSION: The low level of awareness of D-MER suggests that it is necessary to inform and educate mothers and the public about the physiological symptoms of D-MER. Moreover, it is necessary to listen to the feelings of mothers with D-MER and support them in coping with their symptoms.

Evaluating milk flow patterns using the high flow rate period during breast pumping.

PROBLEM: Breast pumping practices have scope for improvement. BACKGROUND: Breast milk weight measurement can be used to evaluate milk flow pattern dynamics during breast pumping. AIM: To determine inter-individual differences in milk flow patterns and their practical implications based on high milk flow rate period (HFP) data among Japanese women expressing breast milk using an electric pump. METHODS: This cross-sectional, observational study analysed data from 19 women (33.0 ± 3.9 years) nursing 1-6-month-old infants and with previous breast milk expression experience. Breast milk was weighed continuously during a 15-min single-breast electric pumping session. The HFP features and flow rate time (≥0.1 g/s) were analysed to determine each individual's milk flow pattern. FINDINGS: The total expressed breast milk was 69.8 ± 42.5 g with a maximum individual flow rate of 0.5 ± 0.2 g/s. The breast milk yielded during the HFPs was 43.1 (34.4-81.3) g, accounting for 82.5 % (69.9-89.5 %) of the total expressed breast milk. HFP occurred 0-3 times during the 15-min session. Multiple discrete and continuous milk flow patterns were observed. Among those with discrete HFP, the HFP interval was 221 (68-371) s. Breast milk fat content changes and subjective residual milk measurements implied sufficient milk removal. A strong positive correlation was noted between HFP length and total breast milk expression volume. DISCUSSION: Individual differences in milk flow patterns were observed among the women using HFP. Milk flow patterns were consistent with previous reports. CONCLUSION: Milk flow pattern data can be used to guide individualised lactation support.

Impact of Dysphoric Milk Ejection Reflex on Mental Health.

Objective: Postpartum mental health, significantly influences breastfeeding. Dysphoric milk ejection reflex (D-MER) is defined as negative emotional reaction to milk ejection, such as unpleasant feelings, anger-irritability or a strange feeling in the stomach. This study investigates the impacts of D-MER on mothers experiencing negative emotions during breastfeeding. Method: This cross-sectional, descriptive study was conducted between July 1 and September 30, 2023 among surveyed mothers with babies of ages 0-2 experiencing discomfort while breastfeeding. Mothers reached out through Instagram and Facebook and completed a semi-structured 45-question survey using a Google form. Results: Out of 141 mothers, 27.7% (n: 39) had D-MER findings. Common emotions included tension (48%), exhaustion (43%), intolerance (41%), hypersensitivity (35%), and restlessness (33%). Symptoms reported to begin within the first month of breastfeeding in 59% of D-MER cases. Nausea was reported in 30% of mothers. The most common conditions that increased the severity of D-MER symptoms were insomnia, stress and breast fullness. Sleeping or resting, being alone, doing something else, drinking cold water, listening to music and talking to mothers who had similar experiences helped the mothers relax. In cases with D-MER findings, about 17.9% considered stopping breastfeeding, with 7.7% stopping. The postpartum depression score was ≥13 in 59% of D-MER cases. Conclusion: D-MER, which can cause early cessation of breastfeeding, may also be associated with the mother's mental health problems. Raising awareness about D-MER and equipping health professionals on this subject are important in the continuity of breastfeeding.

Dysphoric Milk Ejection Reflex: Characteristics, Risk Factors, and Its Association with Depression Scores and Breastfeeding Self-Efficacy.

Background: Dysphoric milk ejection reflex (D-MER) is a phenomenon that occurs before milk letdown and is described as a wave of negative or devastating emotions, ranging from mild to severe and lasting for seconds to minutes. To date, there has been little research regarding this phenomenon. This study aims to determine the prevalence of D-MER in our population as well as its association with postnatal depression scores and breastfeeding self-efficacy. Methods: Lactating persons between 4 and 12 weeks postpartum at our institution were invited to complete an anonymous 59-question survey via an online platform. Questions asked included patient demographics, presence of symptoms of dysphoria (including timing, duration, and frequency), the Edinburgh Postnatal Depression Scale (EPDS), and the Breastfeeding Self-Efficacy Scale Short Form (BSES-sf). Results: In total, 201 women completed the survey. Twelve women were classified as likely having D-MER (6%). Symptom resolution primarily occurred within a minute to 5 minutes (58%). Mean EPDS scores differed significantly between those with likely D-MER and those without (12.2 vs. 5.4, p = 0.002). BSES-sf scores differed significantly between the two groups (43.1 vs. 52.5, p = 0.009). Preexisting depression or anxiety was not associated with D-MER (p = 0.133), other reported mood disorders differed significantly between those with D-MER and those without (p = 0.004). Demographic characteristics of women with and without D-MER were similar. Conclusion: D-MER prevalence may be lower than previously reported. Patients with likely D-MER appear to have lower breastfeeding self-efficacy and higher depression scores. Those with preexisting mood disorders may be at higher risk of experiencing D-MER.