The bovine teat canal: information from measurement of velocity of milk flow from the teat

1986 ◽  
Vol 53 (2) ◽  
pp. 179-185 ◽  
Author(s):  
David M. Williams ◽  
Graeme A. Mein
Keyword(s):  
Mass Flow Rate ◽  
Flow Rate ◽  
Shear Force ◽  
Peak Flow ◽  
Effective Diameter ◽  
Peak Flow Rate ◽  
Milk Flow ◽  
Rate Period ◽  
Flow Through ◽  
Teat Canal

SUMMARYThe velocity of milk flow from the teat during the peak flow rate period of milking was estimated to be ∼ 8·5 m/s with a liner vacuum of 50 kPa and 7·5 m/s at 40 kPa. These results confirm the applicability of the Bernoulli theorem for estimating velocity of milk flow through the teat canal during milking. Concurrent measurements of mass flow rate and velocity indicate that the effective diameter of the open teat canal is ∼ 2 mm. Further calculations indicate that the shear force due to milk flow acting to debride the surface of the open teat canal is about 1·8 × 10-2 N. The opposing surfaces of the ‘closed’ teat canal may be ∼ 100 µm apart immediately after milking. If so, bacteria present in the milk residue within the teat canal would never be more than 50 µm from a surface.

Mechanics of the teat and teatcup liner during milking: information from radiographs

1973 ◽  
Vol 40 (2) ◽  
pp. 179-189 ◽  
Author(s):  
G. A. Mein ◽  
C. C. Thiel ◽  
D. N. Akam
Keyword(s):  
Flow Rate ◽  
Peak Flow ◽  
Peak Flow Rate ◽  
Depth Of Penetration ◽  
Wall Movement ◽  
Milk Flow ◽  
Inner Surface ◽  
Rate Period ◽  
Sinus Pressure ◽  
Made In

SummaryFor radiographic studies of the teat and teatcup liner during milking, quarters were infused with a suspension of propyliodone in milk. Simultaneous recordings of vacuum within the liner, in the mouthpiece chamber and in the pulsation chamber, and recordings of liner-wall movement, were made in conjunction with the radiographs.The studies indicated that the sudden decline in milk flow-rate at the end of the period of peak flow-rate from each quarter, and the concurrent changes in the appearance and position of the teat in the liner, result from a fall in teat sinus pressure. This fall in pressure follows the partial closing of the milk passageway between the teat and udder sinuses. The changes initiating the closing of this connexion seem to occur above the teatcup and are associated with the declining amount of milk in the udder.The teat is elongated by 33–50% as it enters the liner and further stretching of the skin of the teat throughout milking is negligible. Thus, increase in the depth of penetration of the teat into the liner is due to more of the teat entering the top of the liner.The force exerted on the teat by the closed liner, which is greatest near the end of the teat, usually appears to increase near the end of milking. The force acting against the inner surface of the open liner barrel is greatest during the peak flow-rate period and it appears to be fairly uniform over most of the area of contact.

Influence of milk flow rate and streak canal length on new intramammary infection in dairy cows

1991 ◽  
Vol 58 (4) ◽  
pp. 383-388 ◽  
Author(s):  
Robert J. Grindal ◽  
Andrew W. Walton ◽  
J. Eric Hillerton
Keyword(s):  
Flow Rate ◽  
Peak Flow ◽  
Peak Flow Rate ◽  
Secondary Importance ◽  
Flow Rates ◽  
Intramammary Infection ◽  
Susceptibility To Infection ◽  
Milk Flow ◽  
Wide Range ◽  
Mastitis Control

SummaryEighteen cows with a wide range of quarter peak flow rates (0·35–2·22 kg/min) were inoculated with Streptococcus agalactiae and Str. dysgalactiae 4 mm into each streak canal every 3 d for 12 d. Thirty of the 72 quarters developed intramammary infection. Mean peak flow rate and length of streak canal of those quarters that became infected were 1·26 ± 0·08 kg/min (mean ± SEM) and 11·47 ± 0·41 mm respectively, compared with 1·01 ± 0·05 kg/min and 12·05 ± 0·35 mm for those that remained uninfected. Logistic regression analysis showed that the probability of infection increased significantly with the increase in peak flow rate (P = O·O1). The influence of streak canal length on new infection, after allowing for the effect of peak flow rate, was not significant at the 5% level (P = 0·07), suggesting that there may be an inverse relationship between teat duct length and infection, but that it is of secondary importance to peak flow rate. If increased mass of milk distends the teat duct by raising intramammary pressure, then quarter susceptibility to infection is further compromised. These results strongly suggest that the benefits of reduced infection from mastitis control, achieved despite dramatic increases in milk flow rate and milk yield, are significantly underestimated.

scholarly journals Connection of milk flow curve to the somatic cell count in bovine milk

2004 ◽  
Vol 47 (6) ◽  
pp. 551-556 ◽  
Author(s):  
P. Mijić ◽  
I. Knežević ◽  
M. Domaćinović
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Flow Rate ◽  
Flow Curve ◽  
Somatic Cell Count ◽  
Peak Flow ◽  
Bovine Milk ◽  
Correlation Coefficients ◽  
Peak Flow Rate ◽  
Milk Flow

Abstract. The modern equipment introduction into cow milking created technical possibilities for studying the milk flow curve and for using the results in cattle selection. In preventing mastitis, besides curing, other parameters of the milk flow curve could be used preventively. Research showed that cows that had the milk flow curve with a short duration of increasing flow rate (dIFR ≤ 0.40 min) and a larger quotient between the peak and down phase (QPD > 1.20) had also the least somatic cell count in milk (LSCC = 3.47, and 3.30 respectively). Such relation is favourable because increasing the relation, the duration of quick and uniform milking extends, and the duration of peak flow rate shortens. That also show correlation coefficients which were between the logarithmic somatic cell count in milk (LSCC) on one hand and the peak flow rate (dPFR), that means the quotient of peak and down phase (QPD) on the other hand negative (r= −0.25** and –0.27**). Breeding-selective procedures could create bull fathers and mothers with the most desirable milk flow curve and the duration of certain milking phases, whereby the somatic cell count in milk would be the least. Therefore it would be necessary to define desirable proportions of the milk flow curve with a special attention to the cow’s health udder.

scholarly journals Pre-milking mechanical teat stimulation and milking performance of dairy buffaloes in early lactation

2017 ◽  
Vol 48 (1) ◽  
pp. 53-55
Author(s):  
Francesco Maria Tangorra ◽  
Stefania Leonardi ◽  
Valerio Bronzo ◽  
Nicola Rota ◽  
Paolo Moroni
Keyword(s):  
Milk Yield ◽  
Flow Rate ◽  
Peak Flow ◽  
Early Lactation ◽  
Peak Flow Rate ◽  
Flow Rates ◽  
Enhancing Effect ◽  
Milk Flow ◽  
Total Milk ◽  
Automatic Removal

The objective of the present study was to investigate the effect of pre-milking mechanical teat stimulation on milk yield and milking performance of dairy buffaloes in early lactation. For this purpose, twenty-two healthy Italian Mediterranean buffaloes in their first to third lactation and in early lactation (<120 days in milk) were subjected to two treatments of teat stimulation: i) washing of the teats with water for about 5 s and attaching of the milking unit within 60 s, without any pre-milking massage (farm milking routine); ii) fast pulsation (FP), achieved by increasing pulsation rate to 120 pulsations per min during the first 60 s after application of teat cups. Each treatment lasted for 10 days and the following parameters were measured: milk yield (kg/milking), milk yield at 2 min after unit attachment (kg), time between milking unit attachment and its automatic removal (min), peak milk flow rate (kg/min), and milking time to reach peak flow rate (min). The average milk flow rate (kg/min) was calculated by dividing milk yield by the actual milking time. Milk yield was not affected by mechanical pre-stimulation and during the first 2 min of milking 20.2% and 19.6% of total milk yield were milked respectively when treatments 1 and 2 were applied. The time elapsed from attachment of the milking cluster until its automatic removal was less than 8 min both for buffaloes subjected to FP, and for buffaloes subjected just to washing of the teats before attaching the milking unit. FP stimulation did not show an enhancing effect on peak and average milk flow rates and on milking time to reach peak flow rate.

scholarly journals Effect of pre-stimulation on milk flow pattern and distribution of milk constituents at a quarter level

2008 ◽  
Vol 52 (No. 5) ◽  
pp. 117-121 ◽  
Author(s):  
V. Tančin ◽  
M. Uhrinčať ◽  
L. Mačuhová ◽  
R.M. Bruckmaier
Keyword(s):  
Flow Rate ◽  
Dry Matter ◽  
Peak Flow ◽  
Milk Composition ◽  
Peak Flow Rate ◽  
Time Duration ◽  
Decline Phase ◽  
Milk Flow ◽  
Distribution Of Components ◽  
Flow Stripping

The aim of this study was to investigate milk flow patterns and milk composition in relation to pre-milking udder stimulation. The milk of one quarter of each of the sixteen cows was removed separately and in the course of milking it was divided into six fractions (P – cisternal milk during milking without stimulation and the first 300 ml during milking with pre-stimulation, 0&minus;25%, 25&minus;50%, 50&minus;75%, 75&minus;100%, 75&minus;100%, MS-machine stripping) and into five portions (25%, 50%, 75%, 100%, 100% + MS). Two milkings were performed during two consecutive evening milkings with or without manual stimulation. Pre-stimulation resulted in a reduction of milking time, duration of the increase and decline phase of milk flow, stripping yield, but it increased the peak flow rate as compared to milking without pre-stimulation (<i>P</i> < 0.05). In both fractions and portions the content of fat increased steadily during milking and reached a maximum at MS. Lactose increased from P to 50&minus;75% and then it decreased to MS. Significantly higher fat contents at 25% and 50% portions and in both protein and dry matter at 25% portions were found during milking with pre-stimulation as compared to no stimulation (<i>P</i> < 0.05). The content of fat, protein and dry matter were also higher in both P and 0&minus;25% fractions for milking with pre-stimulation (<i>P</i> < 0.05). Pre-stimulation positively influenced the parameters of milk flow and therefore the efficiency of milk removal and contributed to better distribution of components in milk fractions during milking.

scholarly journals Quarter milk flow patterns in dairy cows: factors involved and repeatability

2012 ◽  
Vol 48 (No. 10) ◽  
pp. 275-282 ◽  
Author(s):  
V. Tancin ◽  
A.H. Ipema ◽  
D. Peskovicova ◽  
P.H. Hogeverf ◽  
J. Macuhova
Keyword(s):  
Milk Yield ◽  
Flow Rate ◽  
Peak Flow ◽  
Clinical Mastitis ◽  
Plateau Phase ◽  
Peak Flow Rate ◽  
Flow Parameters ◽  
Milk Flow ◽  
Total Milk

The objectives of our study were to describe the variation of quarter milk flow parameters and to determine the factors that affect these parameters the most. Additionally, repeatabilities (r<sub>2</sub>) of the quarter milk flow traits (duration of milk flow, time to reach peak flow, peak flow rate, and duration of milk flow in single phases &ndash; increase, plateau, decline and blind phase) were calculated. Repeatability of total milk yield and milk yield in single phases was calculated, too. The data from 39 Holstein cows, in their first to third lactation and free of clinical mastitis, were used for statistical analysis. A total of 1 656 curves of quarter milk flows were recorded during six consecutive days. At the last evening and morning milking samples of milk from each quarter were collected for determination of somatic cell count (SCC). Peak flow rate, quarter position, time of milking (morning and evening) and SCC significantly affected most of the measured traits. The highest r2 were for total milk yield and yield of plateau phase 0.53 and 0.50, resp. The lowest r2 were calculated for the duration of increase phase, and milk yield of the increase and blind phase 0.26, 0.12 and 0.21, resp. Peak flow rate, SCC, time of milking and front-rear position influenced the values of r2 of traits to various extent.

Factors affecting mouthpiece chamber vacuum in machine milking

2003 ◽  
Vol 70 (3) ◽  
pp. 283-288 ◽  
Author(s):  
Marianne Borkhus ◽  
Odd Rønningen
Keyword(s):  
Flow Rate ◽  
Peak Flow ◽  
Marked Change ◽  
Air Leakage ◽  
Peak Flow Rate ◽  
Depth Of Penetration ◽  
Factors Affecting ◽  
Milk Flow ◽  
Before And After ◽  
Factorial Trial

The vacuum in the mouthpiece chamber (MPC) was measured in a factorial trial with two liners (DeLaval 964008-01 and DeLaval 999007-03), two pulsator ratios (60 and 70%) and morning and evening milking over eight milkings of ten cows. Teat length and diameter were measured before and after milking, and maximum milk flow rate and depth of penetration of the teat into the teatcup were also recorded. The MPC vacuum at peak flow rate was classified as stable, at various levels, in 79% of the recordings. In the rest of the milkings the vacuum declined gradually, and this decline was associated with gradually deeper penetration of the teat into the teatcup. The DeLaval 964008-01 liner with the narrower bore and larger mouthpiece opening gave lower MPC vacuum at peak flow rate than did the wider bore DeLaval 999007-03 with the smaller mouthpiece opening. Morning milking gave higher MPC vacuum than evening milking. Increased maximum milk flow rate and increased length and diameter of the teat gave decreased MPC vacuum. The teats were longer before milking in the morning than in the evening. However, during peak flow rate, the teats had penetrated deeper into the teatcup in the evening than in the morning. A marked change in MPC vacuum in the transition to the period of flow rate can be used to identify the start of over-milking of an individual teat. A general model explaining the MPC vacuum as the outcome of the balance between air leakage past the mouthpiece lip and the leakage past the teat in the liner barrel is suggested.

scholarly journals Milk flow-controlled changes of pulsation ratio and pulsation rate affect milking characteristics in dairy cows

2009 ◽  
Vol 76 (3) ◽  
pp. 272-277 ◽  
Author(s):  
Sarah Ambord ◽  
Rupert M Bruckmaier
Keyword(s):  
Flow Rate ◽  
Peak Flow ◽  
Phase Changes ◽  
Peak Flow Rate ◽  
Milk Ejection ◽  
Milk Flow ◽  
Group 3 ◽  
Group 2 ◽  
Pulsation Cycle ◽  
Group 1

To test a system with milk flow-controlled pulsation, milk flow was recorded in 29 Holstein cows during machine milking. The three different treatments were routine milking (including a pre-stimulation of 50–70 s), milking with a minimum of teat preparation and milking with milk flow-controlled b-phase, i.e. with a gradually elongated b-phase of the pulsation cycle with increasing milk flow rate and shortening again during decreasing milk flow. For data evaluation the herd was divided into three groups based on the peak flow rate at routine milking (group 1: <3·2 kg/min; group 2: 3·2–4·5 kg/min; group 3: >4·5 kg/min). Compared with routine milking, milking with milk flow-controlled b-phase caused a significant elevation of the peak flow rate and the duration of incline lasted longer especially in cows with a peak flow rate of >3·2 kg/min in routine milking. In milking with a minimum of teat preparation the duration of incline lasted longer compared with the two other treatments. Bimodality of milk flow, i.e. delayed milk ejection at the start of milking, was most frequent at milking with a minimum of teat preparation. No significant differences between routine milking and milking with milk flow-controlled b-phase were detected for all other milking characteristics. In summary, milking with milk flow-controlled b-phase changes the course of milk removal, however mainly in cows with high peak flow rates.

Biological responses of the bovine teat to milking: information from measurements of milk flow-rate within single pulsation cycles

1981 ◽  
Vol 48 (1) ◽  
pp. 7-21 ◽  
Author(s):  
David M. Williams ◽  
Graeme A. Mein ◽  
Murray R. Brown
Keyword(s):  
Mass Flow Rate ◽  
Flow Rate ◽  
Compressive Load ◽  
Secondary Importance ◽  
Maximum Value ◽  
Biological Responses ◽  
Milk Flow ◽  
Thin Walled ◽  
Pulsation Cycle ◽  
Teat Canal

SummaryThe mass flow-rate (FR) of milk from the bovine teat within individual pulsation cycles was measured by continuous computation of the average optical density of the milk–air mixture within a teatcup. Measurements during milking were made on both live and excised teats using a range of teatcup liners, vacuum levels and pulsation characteristics. During a typical pulsation cycle, soon after the start of milking, milk FR from live teats reached a peak within 100 ms of the start of the flow period and fell to about 60% of the maximum value between 0·5 and 1·5 s of flow. If the liner was held open for longer than 1·5 s, the FR typically declined a further 10% over the next 10–15 s. After 10–15 s little or no further change occurred in milk FR at normal milking vacuum levels. Milk flow from excised teats reached a steady value within 100 ms of the start of the flow period and showed no subsequent fall in FR.Within individual pulsation cycles the changes in FR from live teats are affected by: (i) the degree of compressive load applied by the collapsed liner to the teat in the preceding cycle; and (ii) the duration of application of the compressive load. Increasing the degree of compressive load or the length of time of loading increases the peak milk FR of the next cycle by reducing the degree of congestion in the tissues of the teat surrounding the teat canal. Muscular effects are of secondary importance. The relatively small changes in milk FR associated with muscle contractions of the teat can be seen most clearly at low milking vacuum levels (below about 30 kPa) or with an unsupported teat (e.g. using a very distensible, thin-walled liner).

scholarly journals Correlation of intravesical prostatic protrusion with severity of lower urinary symptoms among patients with benign prostatic hyperplasia

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Babatunde K. Hamza ◽  
Muhammed Ahmed ◽  
Ahmad Bello ◽  
Musliu Adetola Tolani ◽  
Mudi Awaisu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Bladder Outlet Obstruction ◽  
Peak Flow ◽  
Prostate Volume ◽  
Outlet Obstruction ◽  
Peak Flow Rate ◽  
The Mean ◽  
Benign Prostate ◽  
Intravesical Prostatic Protrusion ◽  
Lower Urinary

Abstract Background Benign prostate hyperplasia (BPH) is characterized by an increase in the number of epithelial and stromal cells in the periurethral area of the prostate. Lower urinary tract symptoms (LUTS) often develop as a manifestation of bladder outlet obstruction (BOO) due to benign prostate enlargement. When the prostate enlarges, protrusion into the bladder often occurs as a result of morphological changes of the gland. Prostatic protrusion into the bladder can be measured with ultrasound as intravesical prostatic protrusion (IPP). There are studies that have shown IPP as a reliable predictor of bladder obstruction index (BOOI) as measured by pressure flow studies. IPP is thereby reliable in assessing the severity of BOO in patients with BPH. The severity of symptoms in patients with BPH can be assessed through several scoring systems. The most widely used symptoms scoring system is the International Prostate Symptoms Score (IPSS). The aim of this study is to determine the correlation of IPP with IPSS in men with BPH at our facility. Methods The study was a cross-sectional observational study that was conducted at the Division of Urology, Department of Surgery, in our facility. The study was conducted on patients greater than 50 years LUTS and an enlarged prostate on digital rectal examination and/or ultrasound. All consenting patients were assessed with the International Prostate Symptoms Score (IPSS) questionnaire, following which an abdominal ultrasound was done to measure the intravesical prostatic protrusion (IPP), prostate volume (PV) and post-void residual (PVR) urine. All the patients had uroflowmetry, and the peak flow rate was determined. The data obtained were entered into a proforma. The results were analyzed using Statistical Package for Social Sciences (SPSS) software package version 20. Results A total of 167 patients were seen during the study period. The mean age was 63.7 ± 8.9 years, with a range of 45–90 years. The mean IPSS was 18.24 ± 6.93, with a range of 5–35. There were severe symptoms in 49.1%, while 43.1% had moderate symptoms and 7.8% had mild symptoms. The overall mean IPP was 10.3 ± 8 mm. Sixty-two patients (37.1%) had grade I IPP, 21 patients (12.6%) had grade II IPP and 84 patients (50.3%) had grade III IPP. The mean prostate volume and peak flow rate were 64 g ± 34.7 and 11.6 ml/s ± 5.4, respectively. The median PVR was 45 ml with a range of 0–400 ml. There was a significant positive correlation between the IPP and IPSS (P = 0.001). IPP also had a significant positive correlation with prostate volume and post-void residual and a significant negative correlation with the peak flow rate (P < 0.01). Conclusion Intravesical prostatic protrusion is a reliable predictor of severity of LUTS as measured by IPSS, and it also shows good correlation with other surrogates of bladder outlet obstruction.

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