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

Release of oxytocin (OT) is essential for milk ejection in dairy cows (Lefcourt & Akers, 1983; Bruckmaier & Blum, 1998). During milk ejection, alveolar milk is shifted into the cistern, which causes an increase of intracisternal pressure (Bruckmaier et al. 1994). To initiate maximum milk ejection at the start of milking, increasing OT concentration beyond a threshold level is sufficient (Schams et al. 1983). Increasing OT concentration beyond this threshold has no additional effect on intracisternal pressure, i.e., milk ejection (Bruckmaier et al. 1994). Stimulatory effects of milking by hand or by machine or by suckling are well documented (Gorewit et al. 1992; Bar-Peled et al. 1995; Tancin et al. 1995; Bruckmaier & Blum, 1996). At the start of milking, stimulatory effects of machine milking without pre-stimulation or with a manual pre-stimulation and subsequent machine milking cause the release of comparable amounts of OT (Gorewit & Gassman, 1985; Mayer et al. 1985; Bruckmaier & Blum, 1996), whereas the timing of the applied pre-stimulation is important for the shape of the milk flow curve. Should the pre-stimulation period be too short, or absent altogether, the start of the main milk flow is delayed resulting in a bimodal milk flow profile (Bruckmaier & Blum, 1996). Furthermore, the stimulation of only one teat causes an OT release similar to that caused by stimulation of all four teats (Bruckmaier et al. 2001). However, milk production is greater for hand milking or suckling than for machine milking, possibly owing to higher OT concentrations (Gorewit et al. 1992; Bar-Peled et al. 1995).

Download Full-text

Effects of vacuum level and pulsation rate on milk ejection and milk flow traits in Tunisian dairy camels (Camelus dromedarius)

Tropical Animal Health and Production ◽

10.1007/s11250-014-0708-0 ◽

2014 ◽

Vol 47 (1) ◽

pp. 201-206 ◽

Cited By ~ 4

Author(s):

Moufida Atigui ◽

Pierre-Guy Marnet ◽

Ahmed Barmat ◽

Touhami Khorchani ◽

Mohamed Hammadi

Keyword(s):

Camelus Dromedarius ◽

Milk Ejection ◽

Vacuum Level ◽

Pulsation Rate ◽

Milk Flow

Download Full-text

Inhibition of oxytocin release during repeated milking in unfamiliar surroundings: the importance of opioids and adrenal cortex sensitivity

Journal of Dairy Research ◽

10.1017/s0022029901005222 ◽

2002 ◽

Vol 69 (1) ◽

pp. 63-73 ◽

Cited By ~ 18

Author(s):

JULIANA MAČUHOVÁ ◽

VLADIMIR TANČIN ◽

WOLF-DIETER KRAETZL ◽

HEINRICH H. D. MEYER ◽

RUPERT M. BRUCKMAIER

Keyword(s):

Endogenous Opioids ◽

Opioid Antagonist ◽

Control Group ◽

Research Station ◽

Milk Ejection ◽

Milk Flow ◽

Oxytocin Release ◽

And Control ◽

Naloxone Treatment ◽

Vaginal Stimulation

The aim of this study was to test if the opioid antagonist naloxone has a beneficial effect on normalization of oxytocin (OT) release during repeated milking of cows in unfamiliar surroundings. One control milking without naloxone treatment in all cows was performed in the familiar parlour. For four successive evening milkings, cows were transported to, and milked in, the operating theatre of the research station without (control group) or with naloxone administration (1 mg/kg BW) (naloxone group) before milking. After cessation of spontaneous milk flow, but not before 3 min of milking, vaginal stimulation was applied for 2 min. After milk flow ceased again, 10 IU of OT was injected intravenously to remove the remaining milk including residual milk. Milk flow was recorded continuously and blood samples were collected via a jugular vein cannula at 1-min intervals from 1 min before the start of milking until i.v. injection of OT. The inhibition of milk ejection and its normalization during repeated milking in unfamiliar surroundings was not influenced by naloxone treatment. Concentrations of cortisol and β-endorphin during control milking and all relocations were similar in the naloxone and control groups, although their concentrations were higher after relocations than in the control. Therefore, a role of endogenous opioids in the inhibition of milk ejection in unfamiliar surroundings could not be demonstrated. In addition, the effect of exogenous ACTH1–24 (8 IU, i.v.) on the release of cortisol related to the response of cows milked in unfamiliar surroundings was studied. Cows with totally inhibited milk ejection in response to vaginal stimulation during milking after first relocation had numerically, but not significantly lower cortisol levels (8·8±3·4 ng/ml; AUC/min) in response to ACTH than did cows with at least partial milk ejection (38·7±12·9 ng/ml). Thus animals with a higher adrenal response to ACTH seemed to have less severe inhibition of milk ejection.

Download Full-text

Lactational changes in oxytocin release, intramammary pressure and milking characteristics in dairy cows

Journal of Dairy Research ◽

10.1017/s0022029900029708 ◽

1991 ◽

Vol 58 (2) ◽

pp. 159-169 ◽

Cited By ~ 39

Author(s):

Harald Mayer ◽

Rupert Bruckmaier ◽

Dieter Schams

Keyword(s):

Dairy Cows ◽

Milk Yield ◽

Maximum Flow ◽

Pressure Increase ◽

Maximum Pressure ◽

Early Lactation ◽

Milk Ejection ◽

Milk Flow ◽

Oxytocin Release ◽

Almost All

SummaryTwo experiments were conducted to investigate possible changes of milking-related oxytocin release (Expt 1) and of intramammary pressure and milking characteristics (Expt 2) throughout entire lactations in German Braunvieh dairy cows. Mean oxytocin concentrations after stimulation at onset of milking increased from 18·3 ± 15·9 to 30·7 ± 24·1 pg/ml in Expt 1 and decreased from 23·9 ± 17·6 to 15·4 ± 9·1 pg/ml in Expt 2, respectively, but remained above the level necessary to elicit complete milk ejection in both trials. Premilking baseline intramammary pressure had its maximum in early lactation until about month 4 and then decreased to ∼50% of its initial level. Ejection pressure followed a similar pattern, but dropped only to ∼75% of its maximum. This was due to the constant elevation of pressure increase, reaching its highest level in late lactation. Time from commencement of stimulation until maximum pressure exceeded 1 min in almost all instances even in early lactation and increased throughout lactation. Despite the normal decrease of milk yield average milk flow fell only slightly while maximum flow rate remained almost constant. Pressure increase, milk yield and milk flow were not different after 1 min and after extended stimulation. Thus there were no indications of a decreasing sensitivity of the milk ejection reflex during lactation, and milking characteristics were positively affected by intense teat stimulation. Suggestions for practical dairying are made.

Download Full-text

Reduced claw vacuum and b-phase during low milk flow does not impact oxytocin release and milking performance

Journal of Dairy Research ◽

10.1017/s0022029917000504 ◽

2017 ◽

Vol 85 (1) ◽

pp. 70-77

Author(s):

Anna-Lena Neuheuser ◽

Ann-Catherine Schwinn ◽

Olga Wellnitz ◽

Lorenzo E. Hernández-Castellano ◽

Rupert M. Bruckmaier

Keyword(s):

Wall Thickness ◽

Cross Sections ◽

Peak Flow ◽

Milk Ejection ◽

Flow Curves ◽

Flow Rates ◽

Milk Flow ◽

Oxytocin Release

Oxytocin release, milking characteristics, and teat condition were investigated with reduced claw vacuum and pulsation settings compared to milking at regular settings with or without pre-stimulation. The reduced vacuum and pulsation settings during low milk flow are expected to protect the teat tissue before the occurrence of milk ejection at the start of milking, and at the end of milking during a potential overmilking period, i.e. at a milk flow <200 g/min. Seven cows were machine-milked either after a 60 s manual pre-stimulation, or without pre-stimulation and reduced vacuum and pulsation settings, or at full vacuum and normal pulsation during the start of milking. Plasma oxytocin (OT) concentration increased similarly in response to manual pre-stimulation and to both milking with reduced, or with full vacuum and pulsation settings, however delayed by 1 min if the cluster was attached without pre-stimulation. In all treatments OT concentrations remained elevated throughout milking. Milk flow curves were mostly non-bimodal at milkings after manual pre-stimulation and bimodal at milkings without pre-stimulation. The main milking time was shorter and average milk flow was higher during milking after pre-stimulation, but did not differ between treatments without pre-stimulation. Milk yields and peak flow rates were not affected by treatments. Either reduced or full vacuum settings were again applied during an intended overmilking from 200 to 100 g/min of milk flow towards the end of milk harvest. Pre-milking teat ultrasound cross sections were recorded one day before the experiment started. Post-milking ultrasound cross sections were performed at 15 min after each experimental milking. Teat wall thickness was increased after milking as compared to pre-milking but did not differ among treatments. In conclusion, OT release and milking performance are similar if milking is performed with pre-stimulation, or without pre-stimulation but reduced claw vacuum and b-phase during low milk flow.

Download Full-text

Simultaneous recording of oxytocin release, milk ejection and milk flow during milking of dairy cows with and without prestimulation

Journal of Dairy Research ◽

10.1017/s0022029900031708 ◽

1996 ◽

Vol 63 (2) ◽

pp. 201-208 ◽

Cited By ~ 61

Author(s):

Rupert M. Bruckmaier ◽

Jürg W. Blum

Keyword(s):

Flow Rate ◽

Simultaneous Recording ◽

Milk Ejection ◽

Flow Curves ◽

Milk Flow ◽

Oxytocin Release ◽

Plateau Time ◽

Milking Machine ◽

Left Front

SummaryThe effects of manual teat stimulation compared with stimulation by the liner of a conventional milking machine and the influence of milk ejection on the course of milk flow during the entire milking were investigated. Twelve cows were milked with or without prestimulation on three quarters and milk flow was recorded while intramammary pressure (IMP) was recorded in the left front quarter and blood samples for the determination of oxytocin (OT) were taken at 1 min intervals. OT concentrations increased very similarly in response to manual teat stimulation or liner stimulation and remained elevated during the entire milking procedure. Milk flow curves were generally bimodal without stimulation and not bimodal during milking after prestimulation. Milk yield was not significantly lower in milkings without than with stimulation, whereas machine-on time was prolonged and peak milk flow rate was reduced during milking without stimulation. Time to reach milk flow plateau, time to reach peak flow rate and IMP profiles were similar in both treatments if time was calculated from the start of stimulation. IMP increased similarly in response to manual or liner teat stimulation. In milkings with and without prestimulation IMP did not reach its maximum until the start of milking. In bimodal milk flow curves the second increase of milk flow occurred concomitantly with the start of IMP increase; ejection IMP generally occurred concomitantly with the milk flow plateau. In some cases during milking without prestimulation only small and transient OT release was observed. In response, IMP did not increase to its maximum and increased further in response to a stripping-related OT release. During the course of milking IMP decreased slightly because of the emptying of the three milked quarters. After the end of milking, and with OT concentrations decreasing to the premilking values, IMP again decreased slightly to another plateau, probably owing to myoepithelial relaxation. Thus the course of milk ejection, i.e. the IMP profile, influenced milk removal markedly during early milking.

Download Full-text

Effects of morphine and naloxone on the release of oxytocin and on milk ejection in dairy cows

Journal of Dairy Research ◽

10.1017/s0022029999003945 ◽

2000 ◽

Vol 67 (1) ◽

pp. 13-20 ◽

Cited By ~ 13

Author(s):

VLADIMIR TANČIN ◽

WOLF-DIETER KRAETZL ◽

DIETER SCHAMS

Keyword(s):

Dairy Cows ◽

Receptor Agonist ◽

Opioid System ◽

Dependent Manner ◽

Milk Ejection ◽

Milk Flow ◽

Oxytocin Release ◽

Dose Dependent ◽

Μ Receptor ◽

Stimulation Of

The aim of this study was to investigate the action of opioids (the μ receptor agonist morphine) and the antagonist naloxone on inhibition of oxytocin release and milk let-down in response to milking in dairy cows. In the first experiment, cows were injected with 0, 21, 70 and 210 mg morphine 10 min before milking on four successive days. Plasma oxytocin levels after 1 min manual stimulation of the udder were reduced by 70 and 210 mg morphine, and milk let-down was inhibited at the latter dose. In the second experiment, cows were injected after a control milking with 210 mg morphine (or 350 mg at 10 min before milking the following day if not effective) to inhibit milk flow. On the following day the inhibiting dose of morphine was given with 210 mg naloxone. Naloxone injection given before morphine had no effect on plasma oxytocin concentrations, but abolished the inhibition of oxytocin release by morphine and potentiated oxytocin release in response to milking. Naloxone alone injected the day after control milking increased oxytocin levels during milking, suggesting involvement of the opioid system in milking. A model has been developed for the control of opioid effects during milking. Morphine suppressed oxytocin release during milking in a dose-dependent manner and the effect was reversible by naloxone.

Download Full-text

Best combination of pre-stimulation and latency period duration before cluster attachment for efficient oxytocin release and milk ejection in cows with low to high udder-filling levels

Journal of Dairy Research ◽

10.1017/s0022029910000816 ◽

2010 ◽

Vol 78 (1) ◽

pp. 97-104 ◽

Cited By ~ 16

Author(s):

Shehadeh Kaskous ◽

Rupert M Bruckmaier

Keyword(s):

Storage Capacity ◽

Latency Period ◽

Milk Ejection ◽

Suitable Alternative ◽

Milk Flow ◽

Total Milk ◽

Oxytocin Release ◽

Actual Degree ◽

Period Duration ◽

Stimulation Of

Experiments were designed to investigate the suitability of a combination of a short manual teat stimulation with a short latency period before teat cup attachment to induce and maintain oxytocin release and milk ejection without interruption. In Experiment 1, seven dairy cows in mid lactation were manually pre-stimulated for 15, 30 or 45 s, followed by either 30 s or 45 s of latency period. It was shown that all treatments induced a similar release of oxytocin without interruption until the end of milking. In particular, the latency period of up to 45 s did not cause a transient decrease of oxytocin concentration. In Experiment 2, milking characteristics were recorded in seven cows each in early, mid, and late lactation, respectively. Because the course of milk ejection depends mainly on the degree of udder filling, individual milkings were classified based on the actual degree of udder filling which differs between lactational stages but also between morning and evening milkings. All animals underwent twelve different udder preparation treatments, i.e. 15, 30, or 45 s of pre-stimulation followed by latency periods of 0, 30, 45, or 60 s. Milking characteristics were recorded. Total milk yield, main milking time and average milk flow rate did not differ between treatments if the degree of udder filling at the start of milking was >40% of the maximum storage capacity. However, if the udder filling was <40%, main milking time was decreased with the duration of a latency period up to 45 s, independent of duration of pre-stimulation. Average milk flow at an udder filling of <40% was highest after a pre-stimulation of 45 s followed by a latency period of another 45 s. In contrast, average milk flow reached its lowest values at a pre-stimulation of 15 s without additional latency period. However, average milk flow after a 15-s pre-stimulation increased with increasing latency period. In conclusion, a very short pre-stimulation when followed by a latency period up to 45 s before teat cup attachment remains a suitable alternative for continuous stimulation to induce milk ejection.

Download Full-text

Small increases in peripheral noradrenaline inhibit the milk-ejection response by means of a peripheral mechanism

Journal of Endocrinology ◽

10.1677/joe.0.1000337 ◽

1984 ◽

Vol 100 (3) ◽

pp. 337-344 ◽

Cited By ~ 21

Author(s):

A. M. Lefcourt ◽

R. M. Akers

Keyword(s):

Milk Yield ◽

Bolus Injection ◽

Fold Increase ◽

Response To Treatment ◽

Milk Ejection ◽

Milk Flow ◽

Dependent Change ◽

Peripheral Mechanism ◽

Oxytocin Release ◽

Second Peak

ABSTRACT The effects of exogenous noradrenaline on the milk-ejection response were determined for nine Holstein cows. Noradrenaline was injected (0·95 nmol/kg) 15 s after the start of teat stimulation (preparation) or infused (0·13 nmol/kg per min, after bolus injection of 0·47 nmol/kg) starting 10 min before milking for 20 min. Cows were prepared (udder wash and dry) for 1 min before milking. Both injection and infusion resulted in approximately a 3·5-fold increase in peripheral noradrenaline at 1·75 min after the start of milking (baseline noradrenaline 0·83 and 0·89 nmol/l plasma; at 4 min, 2·00 and 3·00 nmol/l). Prolactin release was delayed and oxytocin release enhanced, while milk yield was decreased by 8·6% for both treatments. The maximum rate of milk flow was also depressed by treatment. In contrast, milking time increased for injection and decreased for infusion. In addition, a milk-yield-dependent change in the pattern of milk flow was seen in response to treatment. In medium-yield animals, two distinct milk-flow peaks were apparent and injection delayed the time to the second peak. We conclude that physiologically meaningful increases in peripheral noradrenaline can inhibit milk-ejection response by means of a peripheral mechanism not involving inhibition of release of oxytocin. J. Endocr. (1984) 100, 337–344

Download Full-text

Milk yield, oxytocin and β-endorphin gradually normalize during repeated milking in unfamiliar surroundings

Journal of Dairy Research ◽

10.1017/s0022029900031691 ◽

1996 ◽

Vol 63 (2) ◽

pp. 191-200 ◽

Cited By ~ 23

Author(s):

Rupert M. Bruckmaier ◽

Hans-Ulrich Pfeilsticker ◽

Jürg W. Blum

Keyword(s):

Dairy Cows ◽

Milk Yield ◽

Control Level ◽

Operating Theatre ◽

Milk Ejection ◽

Asymptotic Approach ◽

Blood Samples ◽

Milk Flow ◽

Total Milk ◽

Oxytocin Release

SummaryFor six successive milkings, six dairy cows were relocated immediately before milking to an unfamiliar operating theatre, a procedure previously shown to inhibit oxytocin release and milk ejection. Two control milkings were performed in familiar surroundings. After milk flow had ceased, two i.v. injections of 1 i.u. oxytocin were given to remove the remaining milk. Milk flow was recorded continuously and blood samples were taken every minute during milking and 10 min after milking. During the first milking in unfamiliar surroundings, no oxytocin was released. Thereby, only 13% of the total milk yield, the cisternal milk, was available and the alveolar milk fraction could only be removed after injection of oxytocin. During subsequent relocations oxytocin release steadily increased toward the control level, although the timing of oxytocin release remained delayed as compared with controls. However, the milk fraction available before oxytocin injection increased with increasing number of removals, following an asymptotic approach to control levels. The concentrations of β-endorphin, cortisol (and perhaps also of prolactin) gradually declined with the number of times the animal was moved to unfamiliar surroundings, i.e. hormone concentrations gradually adjusted to control level. During milking, concentrations of prolactin and cortisol increased, while β-endorphin concentrations decreased (except for the first relocation). We conclude that milking-related oxytocin release and therefore milk ejection adapted gradually to repeated relocations to unfamiliar surroundings. This adaptation was inversely related to β-endorphin concentrations, so it is possible that oxytocin release was suppressed by high circulating β-endorphin concentrations.

Download Full-text