Influence of liner design on mouthpiece chamber vacuum during milking

1991 ◽  
Vol 58 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Janthea A. Newman ◽  
Robert J. Grindal ◽  
M. Clare Butler
Keyword(s):  
Flow Rate ◽  
Characteristic Pattern ◽  
Design Experiment ◽  
Slow Flow ◽  
Milk Flow ◽  
Holstein Friesian ◽  
Wide Range ◽  
Pressure Changes ◽  
Slow Flow Rate ◽  
Friesian Cows

SummaryThree types of liner (wide bore tapered, wide bore and narrow bore) were compared in a change-over design experiment comprising three 3-d periods and using six lactating Holstein Friesian cows with a wide range in milk flow rate and teat dimensions. Vacuum levels measured within the liner showed a characteristic pattern of three distinct phases: 1, a mouthpiece chamber (MPC) vacuum that fluctuated with vacuum beneath the teat; 2, a stable MPC vacuum that coincided with the period of peak milk flow and 3, a MPC vacuum that fluctuated with pressure changes in the pulsation chamber and coincided with the period of no or reduced flow. Of the three liners examined, the Gascoigne 1030A (wide bore tapered) induced the highest MPC vacuum (29·4 ± 2·23 kPa, mean ± s.e.m), significantly higher (P < 0·01) than the Alfa-Laval 960000–01 wide bore (23·5 ± 2·32), regardless of teat size and milk flow rate. The Alfa-Laval 7275737–01 (narrow bore) gave a significantly lower value (16·5 ± 1·96) than either of the others (P < 0·001). It was not possible to link absolutely raised MPC vacuum to cow discomfort and teat trauma but circumstantial evidence encourages this view. Narrow teats in combination with slow flow rate appeared to exacerbate MPC vacuum and, because milking time for such animals was protracted, teats were exposed for longer periods.

Dynamic responses of the dairy cow's teat to step changes in pressure

1979 ◽  
Vol 46 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Sybren Y. Reitsma ◽  
Norman R. Scott
Keyword(s):  
Statistical Analysis ◽  
Flow Rate ◽  
Step Change ◽  
Dynamic Responses ◽  
External Diameter ◽  
Milk Flow ◽  
Holstein Friesian ◽  
Delay Times ◽  
Friesian Cows

SUMMARYDynamic responses of the teat end, measured as changes in external diameter and milk flow-rate, due to step changes in pressure, uniformly applied to the whole teat, are presented. The experiment involved a front and a rear teat of each of 6 Holstein–Friesian cows. The measured variables were: (1) step change in pressure, (2) milk flow-rate, (3) step change in external teat end diameter, (4) rise times of pressure and teat end diameter changes, (5) fall times of pressure and teat end diameter changes, and (6) delay times between pressure and teat end diameter changes both at start of rise and of fall times. A statistical analysis showed that front teats expanded more than rear teats (P < 0·05). Several other findings of importance to any system of milk removal through the streak canal of the teat are discussed.

Overmilking causes deterioration in teat-end condition of dairy cows in late lactation

2013 ◽  
Vol 80 (3) ◽  
pp. 344-348 ◽  
Author(s):  
J Paul Edwards ◽  
Bernadette O'Brien ◽  
Nicolas Lopez-Villalobos ◽  
Jenny G Jago
Keyword(s):  
Milk Production ◽  
Flow Rate ◽  
Cow Milk ◽  
Udder Health ◽  
Milk Samples ◽  
Bulk Milk ◽  
Milk Flow ◽  
Holstein Friesian ◽  
Mixed Age ◽  
Friesian Cows

The objective of the study was to determine the effect of varying degrees of overmilking on teat-end hyperkeratosis, milk production variables and indicators of udder health during late lactation. This was examined by assessing the effect of four end-of-milking criteria on 181 spring-calving, mixed-age Holstein-Friesian cows, at an average 217±24 d in milk, over a six-week period. The four treatments were: remove cluster once milk flow rate fell to 0·2 kg/min plus 5 s (Ovr0), plus 120 s (Ovr2), plus 300 s (Ovr5), and plus 540 s (Ovr9). Daily measurements included individual cow milk yield, milking duration, overmilking duration, maximum milk flow rate, milk flow rate at cluster removal and the number of cluster re-attachments. Individual cow bulk milk samples were collected weekly at AM and PM milkings to determine composition (fat, protein and lactose) and somatic cell count (SCC; AM only). Teat-end hyperkeratosis score was assessed at weeks 0, 3, 5 and 6. At week 6 mean teat-end hyperkeratosis score of the Ovr2 treatment was not greater than Ovr0, whilst Ovr5 was greater than Ovr2 and Ovr9 was greater than Ovr5 and Ovr2. Milk production, milking characteristics and SCC were not different between treatments, except milking duration and milk flow rate at cluster removal. However, higher teat-end hyperkeratosis scores may have a longer-term impact on indicators of udder health if teat-end condition reaches severe levels. Results indicate that to minimise changes in teat-end condition overmilking should be limited to 2 min, which has implications for milking management in large parlours not fitted with automatic cluster removers.

RELATIONSHIPS OF TEAT CONFORMATION AND UDDER HEIGHT TO MILK FLOW RATE AND MILK PRODUCTION IN HOLSTEINS

1981 ◽  
Vol 61 (2) ◽  
pp. 493-501 ◽  
Author(s):  
R. K. MOORE ◽  
SUSAN HIGGINS ◽  
B. W. KENNEDY ◽  
E. B. BURNSIDE
Keyword(s):  
Milk Production ◽  
Flow Rate ◽  
Production Traits ◽  
Stage Of Lactation ◽  
Milk Flow ◽  
Holstein Friesian ◽  
Negative Effect ◽  
Fat Yield ◽  
Quadratic Effects ◽  
Friesian Cows

Teat conformation characteristics, udder height, total milking yield, 2-min yield, 2-min yield adjusted for the linear and quadratic effects of total milking yield, and 305-day milk and fat yields were recorded on 377 Holstein-Friesian cows in 18 herds. Simple relationships of teat conformation measures and udder height to milk flow rate and production traits which were significant (P < 0.05) were as follows. Mean 2-min, total milking, and 305-day milk yields were lower for plumb front teats than for front teats that were not plumb. Cows with plumb rear teats also had lower total milking yields. Cows with cylindrical teats, both front and rear, had lower total milking yields than cows with funnel teats. Teat length was positively correlated with total milking, 305-day milk and 305-day fat yields. Teat diameter measures taken at proximal, medial and distal locations of the teat were positively correlated with all production traits, and rear teat diameter measures were positively correlated with 2-min yield. Udder height was positively correlated with adjusted 2-min yield and negatively correlated with total milking, 305-day milk and 305-day fat yields. Least squares analyses, which corrected for the effects of herd, age of cow at calving, and stage of lactation, were conducted, and significant (P < 0.05) effects were as follows. Cows with cylindrical teats produced 0.7–0.8 kg less total milk at milking than cows with funnel teats. Rear teat diameter was more highly related to milk production than front teat diameter. Proximal and distal diameter of the rear teat was positively associated with all three production traits, and medial rear teat diameter was positively associated with total milking and 305-day milk yields. Also, proximal diameter of the rear teat had a positive relationship with 2-min yield. Total milking yield was positively influenced by front teat proximal and medial diameters, but medial diameter had a negative effect on adjusted 2-min yield. Udder height influenced all traits. High udders had relatively higher milk flow rates but lower milk and fat production. Each centimetre increase in udder height was associated with a 46-kg decrease in 305-day milk. Heritabilities of 2-min yield, adjusted 2-min yield, 305-day milk yield and 305-day fat yield were 0.17, 0.27, 0.18, and 0.50, respectively.

scholarly journals Mechanoregulation of BK channel activity in the mammalian cortical collecting duct: role of protein kinases A and C

2009 ◽  
Vol 297 (4) ◽  
pp. F904-F915 ◽  
Author(s):  
Wen Liu ◽  
Yuan Wei ◽  
Peng Sun ◽  
Wen-Hui Wang ◽  
Thomas R. Kleyman ◽  
...  
Keyword(s):  
Flow Rate ◽  
Collecting Duct ◽  
Bk Channel ◽  
Slow Flow ◽  
Cortical Collecting Duct ◽  
Flow Rates ◽  
Calphostin C ◽  
Flow Stimulation ◽  
Slow Flow Rate ◽  
Stimulation Of

Flow-stimulated net K secretion ( JK) in the cortical collecting duct (CCD) is mediated by an iberiotoxin (IBX)-sensitive BK channel, and requires an increase in intracellular Ca2+ concentration ([Ca2+]i). The α-subunit of the reconstituted BK channel is phosphorylated by PKA and PKC. To test whether the BK channel in the native CCD is regulated by these kinases, JK and net Na absorption ( JNa) were measured at slow (∼1) and fast (∼5 nl·min−1·mm−1) flow rates in rabbit CCDs microperfused in the presence of mPKI, an inhibitor of PKA; calphostin C, which inhibits diacylglycerol binding proteins, including PKC; or bisindolylmaleimide (BIM) and Gö6976, inhibitors of classic and novel PKC isoforms, added to luminal (L) and/or basolateral (B) solutions. L but not B mPKI increased JK in CCDs perfused at a slow flow rate; a subsequent increase in flow rate augmented JK modestly. B mPKI alone or with L inhibitor abolished flow stimulation of JK. Similarly, L calphostin C increased JK in CCDs perfused at slow flow rates, as did calphostin C in both L and B solutions. The observation that IBX inhibited the L mPKI- and calphostin C-mediated increases in JK at slow flow rates implicated the BK channel in this K flux, a notion suggested by patch-clamp analysis of principal cells. The kinase inhibited by calphostin C was not PKC as L and/or B BIM and Gö6976 failed to enhance JK at the slow flow rate. However, addition of these PKC inhibitors to the B solution alone or with L inhibitor blocked flow stimulation of JK. Interpretation of these results in light of the effects of these inhibitors on the flow-induced elevation of [Ca2+]i suggests that the principal cell apical BK channel is tonically inhibited by PKA and that flow stimulation of JK in the CCD is PKA and PKC dependent. The specific targets of the kinases remain to be identified.

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.

The Effect of Dry Matter Content of A Straw/Sugar Beet Pulp Mixture Used As A Buffer Feed When Fed to Dairy Cows at Different Stages of Lactation

1994 ◽  
Vol 1994 ◽  
pp. 5-5
Author(s):  
A Hameleers ◽  
T Bronda ◽  
D J Roberts
Keyword(s):  
Sugar Beet ◽  
Dairy Cows ◽  
Dry Matter ◽  
Matter Content ◽  
Design Experiment ◽  
Dry Matter Content ◽  
Stage Of Lactation ◽  
Wide Range ◽  
Beet Pulp ◽  
Friesian Cows

Buffer feeding is a widely used strategy to improve DM intakes from dairy cows at grass. A very wide range of products have been used as buffer feeds resulting in a wide range of responses. Less well understood are which factors are important in explaining these responses. In this experiment the buffer feed characteristic “dry matter content” and the animal factor “stage of lactation” were used as variables in order to gain a better understanding of responses to buffer feeding.Forty Friesian cows, of which 20 were spring calving and 20 autumn calving were used in a continuous design experiment lasting 5 weeks from 3 May until 7 June 1993. The animals were allocated to four treatments on basis of milk yield, liveweight and stage of lactation. The treatments were grazing only (C), grazing and a buffer feed at 30% DM (B30), 50% DM (B50) and 80% DM (B80) and for each treatment half the cows were spring calving (S) or autumn calving (A). The grazing consisted of a 8 ha field of predominantly perennial ryegrass which was split into 4 equal paddocks which were grazed on a daily rotational basis.

scholarly journals Temperament of Holstein Friesian cows in milking parlour and its relation to milk production

2008 ◽  
Vol 56 (1) ◽  
pp. 201-208 ◽  
Author(s):  
Andrea Szentléleki ◽  
Jeremy Hervé ◽  
Ferenc Pajor ◽  
Daniel Falta ◽  
János Tőzsér
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Correlation Coefficients ◽  
Production Traits ◽  
Milk Production Traits ◽  
Point Scale ◽  
Milk Traits ◽  
Milk Flow ◽  
Holstein Friesian ◽  
Friesian Cows

The aim of this study was to evaluate the change of temperament of Holstein cows scored before and during milking during the entire lactation and to calculate correlation between temperament measured in the two moments as well as milk production traits and temperament. Observations were carried out on 17 primiparous Holstein Friesian cows starting their lactation within 85 days. Measurements of temperament and milk production traits were taken once in each month of the lactation, during the morning milking, in a milking parlour. Temperament was assessed in a 5-point scale during udder preparation and milking procedure (1: very nervous, 5: very quiet). Data of milk yield and milk flow were collected individually on each test day morning. Results showed changes during the lactation in temperament of cows scored directly before milking (P < 0.01), however, temperament during milking did not alter with months (P > 0.10). By correlation coefficients, behaviour assessed in the two moments cannot be regarded as the same. In addition loose, significant relations were found only between milk traits and temperament before milking.

Effects of habituation to the milking parlour on production, health and fertility of Norwegian and Holstein dairy herd replacements

2003 ◽  
Vol 2003 ◽  
pp. 26-26
Author(s):  
H.C.F. Wicks ◽  
A.F. Carson ◽  
M.A. McCoy
Keyword(s):  
Milk Yield ◽  
Flow Rate ◽  
Transition Period ◽  
Dairy Herd ◽  
Nutritional Management ◽  
Social Changes ◽  
Subsequent Performance ◽  
Milk Flow ◽  
Holstein Friesian ◽  
Norwegian Dairy

During the transition period (defined as three weeks prior to calving to three weeks post-calving) heifers are exposed to physiological, nutritional, management, and social changes as they enter the dairy herd. One obvious change is the introduction of heifers to the milking parlour. Previous work has shown that when mature cows were milked in unfamiliar surroundings, milk yield, milk flow rate and milking duration were affected due to increased stress (Rushens, et al. 2001). The objective of the current study was to investigate the effects of habituating heifers to the milking parlour pre-calving on the subsequent performance of Holstein-Friesian and Norwegian dairy herd replacements.

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