Milking performance evaluation and factors affecting milking claw vacuum levels with flow simulator

Milking performance of milking machines that matches the production capability of dairy cows is important in reducing the risk of mastitis, particularly in high‐producing cows. This study used a simulated milking device to examine the milking performance of the milking system of 73 dairy farms and to analyze the factors affecting claw vacuum. Mean claw vacuum and range of fluctuation of claw vacuum (claw vacuum range) were measured at three different flow rates: 5.7, 7.6 and 8.7 kg/min. At the highest flow rate, only 16 farms (21.9%) met both standards of mean claw vacuum ≥35 kPa and claw vacuum range ≤ 7 kPa, showing that milking systems currently have poor milking performance. The factors affecting mean claw vacuum were claw type, milk‐meter and vacuum shut‐off device; the factor affecting claw vacuum range was claw type. Examination of the milking performance of the milking system using a simulated milking device allows an examination of the performance that can cope with high producing cows, indicating the possibility of reducing the risk of mastitis caused by inappropriate claw vacuum.     

A case study of improving milking cow performance and milking system performance with using a flow simulator

Efforts to improve dairy performance have been focused on increasing milk productivity of cows through improved feeding systems and genetic potential. However, methods for evaluating milking system performance based on milk productivity have not yet been established. Milking system performance was evaluated by measuring the claw vacuum at five flow rates (1.9–8.7 kg/min) produced using a flow simulator for a single eight‐swing milking parlor with a high‐line system. Based on these results, a double eight‐parallel milking parlor with a low‐line system was installed and tested. Farmers can take data obtained from evaluations of milking system performance into account for future management decisions, such as renewing the milking system. By renewing the milking system, average milking productivity, somatic cell linear score (LS) of bulk milk, and LS of each cow were significantly improved in the year after installing the new system (p < .01). In addition to checking conventional milking systems, this novel diagnostic method using a flow simulator can be used for checking new installations and also for proposing renovations.     

Effect of liner design,pulsator setting,and vacuum level on bovine teat tissue changes and milking characteristics as measured by ultrasonography

: Friesian-type dairy cows were milked with different machine settings to determine the effect of these settings on teat tissue reaction and on milking characteristics. Three teat-cup liner designs were used with varying upper barrel dimensions (wide-bore WB = 31.6 mm; narrow-bore NB = 21.0 mm; narrow-bore NB1 = 25.0 mm). These liners were tested with alternate and simultaneous pulsation patterns, pulsator ratios (60:40 and 67:33) and three system vacuum levels (40, 44 and 50 kPa). Teat tissue was measured using ultrasonography, before milking and directly after milking. The measurements recorded were teat canal length (TCL), teat diameter (TD), cistern diameter (CD) and teat wall thickness (TWT).Teat tissue changes were similar with a system vacuum level of either 50 kPa (mid-level) or 40 kPa (low-level). Widening the liner upper barrel bore dimension from 21.0 mm (P < 0.01) or 25.0 mm (P < 0.001) to 31.6 mm increased the magnitude of changes in TD and TWT after machine milking. Milk yield per cow was significantly (P < 0.05) higher and cluster-on time was reduced (P < 0.01) with the WB cluster as compared to the NB1 cluster. Minimum changes in teat tissue parameters were achieved with system vacuum level of 40 kPa and 50 kPa using NB and WB clusters, respectively. Similar changes in teat tissue and milk yield per cow were observed with alternate and simultaneous pulsation patterns. Widening pulsator ratio from 60:40 to 67:33 did not have negative effects on changes in teat tissue and had a positive effect on milk yield and milking time. Milk liner design had a bigger effect on teat tissue changes and milking characteristics than pulsation settings.     

Influence of milking units and working vacuum level on the mechanical milking of goats

The objectives of this study were to evaluate and compare the effect of working vacuum levels (35 and 44 kPa) and liners dimensions (mouthpiece lip diameter and overall length, 20–185 and 22–170 mm) on the main milking characteristics of goats. The results highlight that both the working vacuum level and the liner dimension have influenced the milk flow curve parameters. The maximum variations were found for peak flow rate, which increased significantly with liner dimensions of 20–185 mm at a working vacuum level of 44 kPa as well as average milk flow rate and for plateau phase duration. The incorrect adoption of operative parameters and unsuitable milking machine components, might affect the performance of the mechanical milking and negatively affecting animal productions and welfare.     

Milk production,plasma metabolite profiles and mammary arterial‐venous differences of milk precursors in early lactation cows milked at different frequencies by an automatic milking system

The objective of this study was to clarify the effect of different milking frequencies under an automatic milking system (AMS) on milk yield, plasma metabolite profiles and mammary arterial‐venous (A‐V) differences of milk precursors by mammary tissues in early lactation cows. Twelve Holstein cows were divided into two and four times milking frequency treatments by AMS after calving to 50 days postpartum. Cows were given a partial mixed ration ad libitum and a concentrate diet at every milking. Dry matter intake increased similarly in both treatments with advancing postpartum days. Milk yield was greater (P < 0.001) by 25% with four times milking, but milk composition was not affected by milking frequency. Body weight change was also not affected by milking frequency. Arterial concentrations of glucose and glutamate were lower (P < 0.05) for four times milking frequency. However, arterial concentration of nonesterified fatty acids did not differ between treatments. Although mammary A‐V differences of plasma concentration for most milk precursors did not differ between treatments, estimated plasma flow was higher (P < 0.05) for four times milking frequency. These results indicate that higher milking frequency may increase mammary uptake of milk precursors, whereas may not affect the extent of fat mobilization of early lactating cows from day 20 postpartum onward.     

Effect of an automatic milking system on milking traits

Recent studies in Japan of the effect of automatic milking systems (AMS) on the behavior of dairy cows have confirmed the labor-saving aspect of AMS, but have not solved some of the problems affecting milking traits. The influence of AMS on milking was examined in 39 Holstein cows at Iwate Agricultural Research Center from June 1998 to December 1999, by measuring and recording the yield per milking, milking finish time, milking frequency, and daily yield of milking. Four milking traits were analyzed separately as the objective variable in a linear model, with parity, days in milking, month after installation of the AMS as independent variables. Primiparous cows milked more frequently in the middle and late stage of lactation, yielded less per milking and less per day in the early stage of lactation than multiparous cows with the AMS. Lower frequencies were observed at noon and midnight for cleaning of the bulk tank. By contrast, higher milking frequency in the forenoon was shown. The yield per milking rose and declined, following a normal lactation curve. However, milking frequency rose slowly, and declined gradually in the late stage of lactation. After installing a one-way gate, the cows milked more frequently, with a lower yield per milking and a greater daily milk yield, than before installation.     

Quarter-milking-, quarter-, udder- and lactation-level risk factors and indicators for clinical mastitis during lactation in pasture-fed dairy cows managed in an automatic milking system

Objectives To identify risk factors and indicators at quarter‐milking and other levels for clinical mastitis during lactation in pasture‐fed cows managed in an automatic milking system. Design A retrospective nested case–control study using data collected over a 31‐month period. A total of 803,948 quarter‐milkings from 249 cows were available for analysis, of which 245 were selected as clinical mastitis quarter‐milking cases and 2450 unaffected quarter‐milkings were selected as controls. Most of the diagnoses of clinical mastitis had been made after clinical assessments of quarters following automated alerts by the milking system. Potential risk factors and indicators were assessed using univariable and multivariable multilevel logistic models. Results Quarters that are milked infrequently and have low yield, fast peak milk flow rates, blood in the milk and/or elevated milk conductivity are at increased risk of clinical mastitis. Quarters were also at increased risk between days 10 and 29 of lactation, and during higher parity lactations. Milk fat and protein concentrations and the fat : protein ratio were not significantly associated with the development of clinical mastitis. Neither quarter position (fore or rear) nor side (left or right) was associated with clinical mastitis occurrence. Quarters that had been clinically affected more than 30 days previous in the current lactation were not at increased risk of redeveloping clinical mastitis. Conclusions Under the study conditions, the risk of clinical mastitis increased for quarter‐milkings in quarters that were milked less frequently in the previous 7 days, were low‐yielding, had fast peak milk flow rates and had more milkings in which blood was detected in milk and/or the milk conductivity was elevated. Risk was also increased in days 10–29 of lactation and in higher parity lactations.     

Association of automatic milking systems milking frequency in primiparous and multiparous cows with their yield and milkability

The aim of the study was to determine the association of automatic milking systems milking frequency (≤2.40, 2.41–2.80 and >2.80 times/day) in primiparous and multiparous cows with their daily milk yield and milkability. The analysis included of the milk production level and the interaction between milking frequency per day and daily milk yield. Regardless of the daily production level, most primiparous cows were milked 2.41–2.80 times/day and most multiparous cows >2.80 times/day. Higher daily milk yield and a more favourable effect of increasing milking frequency on this parameter were observed in multiparous cows, with an increase from 29.7?kg (milking frequency ≤2.40 times/day) to 31.1?kg milk (>2.80 times/day). In primiparous cows, this increase was smaller and amounted to 0.8?kg milk (from 29.2 to 30.0?kg).     

Influence of milking technique, milking hygiene and environmental hygiene parameters on the microbial contamination of milking machines

It was the aim of this study to investigate the effect of various factors of the milking technique, milking hygiene and environment on microbial contamination of the milking machine. In 31 dairy herds, the degree of bacterial contamination was examined by taking swabs at four locations (teat cup liner, claw, short and long milk tube) before the milking procedure was started using a standardized protocol (DIN ISO 6887-1:1999). Furthermore, the total germ count was determined in the first milk entering the bulk tank as well as in the bulk tank milk following milking. For each farm, the quality of the milking process and the condition of the milking machine as well as of various environmental factors were recorded. A subjective evaluation of the status of the milking cluster or other parts of the milking machine ("good" or "moderate-poor") gave more information about bacterial contamination than the determination of age and type of material used. A temperature of the rinsing water of < 42 degrees C increased the contamination with Pseudomonas spp. and coliform bacteria. Milking clusters kept out of the cluster pick-up between milking had a higher risk of microbial contamination. Various methods of teat cleaning before milking or of postmilking teat disinfection did not affect the contamination of the milking machine and the bulk tank milk with environmental bacteria. Furthermore, type of bedding material affected bacterial contamination of milking clusters and bulk tank milk. In conclusion, our results suggest that the microbial contamination of the milking machine is not only influenced by the sanitation pro-     

Effect of vacuum level on milking efficiency, somatic cell counts (SCC) and teat end wall thickness in ewes of Greek mountain Boutsiko breed

The aim of this work was to determine the effect of vacuum level of machine milking on milk yield, milk composition, milking efficiency, somatic cells counts (SCC), and teat end thickness of the Greek mountain breed Boutsiko ewes. Seventy two ewes after a suckling period of 45 ± 5 days were divided into three equal groups of 24 animals for level of milk production, prolificacy and lactation number. The overall experiment lasted 14 weeks. All groups were milked with a pulsation rate of 120/min, pulsator ratio of 50/50, and three vacuum levels of 38, 44 and 50 kPa, respectively, were applied for the three groups. Every two weeks, in a.m. and p.m. milking, measurements were taken for machine milk (MM) and machine stripped milk (MSM), milk composition, SCC, milk emission characteristics (only in a.m. milking) and teat end wall thickness (TEWT) before and after milking. The results have shown that the lower vacuum level of 38 kPa increased (P < 0.05) the percentage of machine milk (82.9%). There were no significant differences among the groups for milk composition, milk flow rate and SCC, but there was a difference in log SCC (P < 0.05) between 38 and 50 kPa. The teat end wall thickness was lower at the lower vacuum level (38 kPa) after milking, and increased (P < 0.001) as the vacuum level was raised to 50 kPa. The findings of this study suggest that with a lower vacuum level of 38 kPa, the ewes are milked better than those with 44 or 50 kPa. Also, the irritation of teats is considerably reduced, while no differences were seen regarding the health of the udder.     

Estimates of genetic parameters for milkability from automatic milking

Genetic parameters were estimated by restricted maximum likelihood with a multi-trait animal model for three milkability traits with serial data from an automatic milking system from a research farm (401 dairy cows) collected between September 2000 and June 2003 (320834 milkings). Furthermore, daily values for milk yield and milkability were formed from all single milkings resulting in 104 132 records and, subsequently, an estimation of genetic parameters was carried out based on these daily values.The resulting estimated heritability coefficients (based on daily values) are h² = 0.55, h² = 0.55 and h² = 0.39 for average milk flow, maximum milk flow and milking time, respectively. The heritabilities are at a high level and thus breeding for good milkability makes sense. The genetic correlations between the three milkability traits are near unity with r_g = 0.98 between average and maximum milk flow, r_g = − 0.89 between average milk flow and milking time and r_g = − 0.86 between maximum milk flow and milking time. Thus it may be sufficient to record only one of these traits in performance tests. The genetic correlations between milk yield and average milk flow, maximum milk flow and milking time are r_g = 0.51, r_g = 0.44 and r_g = − 0.23, respectively.In future, serial data on milkability, already existing on many farms with automatic milk yield recording, should be used to greater extent for selective breeding with the aim of achieving good milkability.     

Forecasting the milk yield of cows on farms equipped with automatic milking system with the use of decision trees

The purpose of this paper was to utilize the decision trees technique to determine the factors responsible for high monthly milk yield in Polish Holstein‐Friesian cows from 27 herds equipped with milking robots. The applied statistical method—the decision tree technique—showed that the most important factors responsible for monthly milk yield of dairy cows using robots were, in descending order of importance: milking frequency, lactation number, month of milking, and type of lying stall. At the same time, it has been ascertained that the highest monthly milk yield (47.24 kg) can be expected from multiparous cows kept in barns with a deep bedding that were milked more frequently than three times per day. On the other hand, the lowest milk production (13.56 kg) was observed among dairy cows milked less frequently than two times a day, with an average number of milked quarters lower than 3.97. The application of the decision trees technique allows a breeder to select appropriate levels of environmental factors and parameters that will help to ensure maximized milk production.     

A comparison of the direct and residual response of dairy cows to once or twice-daily milking, in late lactation

Two experiments were undertaken to examine the direct and residual responses of late lactation (mean of 232 days calved) autumn calving dairy cows (Experiment 1), and late lactation (mean of 240 days calved) spring calving dairy cows (Experiment 2), to once-daily milking. Experiments 1 and 2 involved 50 and 44 Holstein–Friesian dairy cows respectively. In each of the two experiments, cows were milked either once daily (ODM) or twice daily (TDM), during the late lactation period (mean of 79 and 66 days in Experiments 1 and 2 respectively). Cows in Experiment 1 were managed within a grazing system, and were offered 3.0 kg of concentrate/day, while cows in Experiment 2 were housed, and offered grass silage supplemented with 6.0 kg concentrate/day. Forty-one cows from Experiment 1, and 32 cows from Experiment 2, completed the first eight weeks of the subsequent lactation on a twice-daily milking regime. Food intakes were not measured in Experiment 1, while treatment had no significant effect on dry matter intake in Experiment 2 (P > 0.05). In each of Experiments 1 and 2, total milk output was increased with twice-daily milking (P ≤ 0.05), while milk fat (P ≤ 0.01) and protein (P < 0.001) concentrations increased with once-daily milking. Somatic cell counts were higher with animals milked once daily in Experiment 1 (P < 0.001), while not being significantly affected by milking frequency in Experiment 2 (P > 0.05). Milking frequency had no significant effect on cow live weight or on cow condition score at the point of drying off in either Experiment (P > 0.05). Milking time per cow during morning milking was unaffected by treatment in either experiment, while total daily milking time per cow (morning and evening combined) was significantly longer with the TDM treatment (P < 0.001). In Experiment 1, milk flow rates during the morning milking were higher with animals on the ODM treatment, compared to those on TDM treatment (P < 0.001), while being unaffected by treatment in Experiment 2 (P > 0.05). Neither daily milk yield, milk fat content, milk protein content, or somatic cell count during the subsequent lactation, were affected by previous lactation milking frequency in either of Experiments 1 or 2 (P > 0.05).     

New aspects of the physiology of milking with special reference to the teat smooth musculature in teat rubber-free extraction

The following frequencies of change between 30 kPa milking vacuum and atmospheric pressure were used in a milking experiment with single-space cups: 0.05 Hz, 0.1 Hz, 0.2 Hz, 0.35 Hz, 0.5 Hz, 0.65 Hz, 0.8 Hz, and 0.95 Hz. Milking cup pressure and instantaneous milk flow rate through the teat canal were repetitively recorded ten times per second. Four clearly distinguishable and reproducible forms of flow rate oscillations were observed across several sucking phases together with four equally distinguishable and reproducible forms of profiles of a variable milk flow rate within one sucking phase. The occurrence of those differentiated forms of milk flow was found to be correlated primarily with both the sucking phase frequency applied and the average milk flow rate. These findings seem to be indicative of active control of teat canal diameter or milk flow rate by the unstriated teat musculature.     

荷斯坦牛泌乳速度指标影响因素分析

【目的】 探究荷斯坦牛泌乳速度相关指标的群体规律及非遗传因素对其的影响。【方法】 收集华东地区某规模化牧场8 757头泌乳牛的906 748条挤奶记录，定义了班次产奶量、前两分钟产奶量、挤奶时间、前两分钟产奶量占比、平均流速和最高流速6个泌乳速度指标，并对其进行了描述性统计，计算了各指标间的Pearson相关系数，采用固定模型分析了测定季节、胎次、泌乳阶段、初产月龄和挤奶班次对泌乳速度相关指标的影响。【结果】 6个泌乳速度指标中，除前两分钟产奶量占比之外，班次产奶量、前两分钟产奶量、挤奶时间、平均流速和最高流速均基本呈对称分布，各个指标的变异较大，变异系数在30%左右；各指标两两之间存在极显著相关关系，相关系数在-0.84~0.89之间，泌乳速度与产奶量呈中等或强相关，与挤奶时间呈弱负相关，与前两分钟产奶量占比呈弱正相关。测定季节、胎次、泌乳阶段、初产月龄和挤奶班次对泌乳速度指标均有极显著影响（P<0.01）；不同季节中，冬季的班次产奶量和挤奶时间最大，夏季的平均流速最快，而秋季的最高流速最快；不同泌乳阶段中，在第Ⅱ泌乳阶段（45~99 d），奶牛的班次产奶量、挤奶时间、平均流速和最高流速均最大；不同班次中，在夜间班次（00：00—06：00），奶牛的班次产奶量、挤奶时间、平均流速和最高流速均为最大。【结论】 奶牛泌乳速度指标存在较大变异，对季节、胎次等环境和生理因素较为敏感，可为奶牛产奶性能的选育提供信息。     

Sensors and management support in high-technology milking

Two directions can be distinguished in the development of high-tech milking equipment: 1) high-capacity milking parlors with a high throughput of cows per person per hour and 2) automatic milking systems in which manual labor is replaced by a milking robot. High-capacity milking parlors are developed in such a way that one operator is able to milk many cows, partly by automation and partly by optimization of available labor. In such parlors, one operator can milk up to 125 cows per hour. This means that there are only a few seconds available for udder preparation. In an automatic milking system, a robot takes over all manual labor during milking. Currently available systems have one robot arm working with one milking stall (one-stall system) or one robot arm working with more milking stalls (multiple-stall systems). Cows have to go to the automatic milking system voluntarily. Therefore, there is a large variation in milking intervals. Moreover, a large variation between milkings and between cows was observed in milk flow rate, machine-on time and udder preparation time. Both developments in high-tech milking have effects on the milk ejection. The small amount of time dedicated to udder preparation in high-capacity milking parlors has negative effects on the milk ejection, among others leading to more bimodal milk flow curves and longer machine-on time. In automatic milking systems, the variation in time between udder preparation and cluster attachment and in milking frequency might have an effect on milk ejection. Lactation physiology can play a role in solving the questions around milk ejection in high-tech milking systems. The introduction of high-tech milking systems makes decision support systems using sensors necessary. These systems should assist in detection of abnormal milk and mastitis. To a lesser extent, diseased cows need to be brought to the attention of the dairy farmer. Some sensors are currently available for this purpose, but they do not fulfill all demands. In the near future other sensors might be developed. It is important that this development is demand driven and not technology driven. Lactation physiology can play an important role in the determination of milk components useful for automatic detection.     

The impact of installation of automatic milking system on production and reproduction traits of dairy cows

The objective of the research was the evaluation of change in the traditional milking system using automatic milking system in the scope of the selected reproduction features of dairy cows of the Polish Holstein–Friesian breed. Animal material consisted of 2,818 cows used on nine farms equipped with the automatic milking system Astronaut A4 made by Lely. The cows were controlled in the scope of services per conception, service period, length of pregnancy, calving interval and calving to conception period, milk yield, protein and fat content obtained in lactations of 305 days. The selected traits were observed between 2005 and 2015. In this period, the milking system was changed from the conventional to automated one. The collected data material was statistically processed, using the multifactorial analysis of variance. The period between the first calving and the second effective insemination was reduced by 11.8 days, and the period between the second calving and the third effective insemination was shortened by 4 days after the installation of the automatic milking system. The increase in milk yield by 466 kg during 305‐day lactation was observed among primiparous cows. The percentage of protein and fat content in the researched groups decreased; moreover, the fall of intergroup variability was noticeable, which may be a sign of the levelling of the yield within the herd.     

挤奶厅挤奶卫生检测的关键点分析

挤奶设备和挤奶厅的卫生对原料乳的质量有着重要的影响。作者介绍了挤奶厅检测的几个关键点：挤奶机奶衬、挤奶机真空压水平、挤奶机滤膜、挤奶机脉动管和脉动器及挤奶后挤奶机的洁净度;挤奶厅的卫生及挤奶操作和储奶管的清洗。通过加强挤奶厅关键点的检测从而保证原料乳质量。     

'Looking up' behavior in the holding area of the milking parlor: its relationship with step-kick, flight responses and productivity of commercial dairy cows

Commercial dairy cows milked in a parlor system are packed close together in the holding area before milking. The present study examined the relationships of ‘looking up’ behavior with some other behaviors and the productivity of 1116–1153 cows from five farms. The individual identities of the cows looking up in the holding area were recorded at 5 min intervals during six intermittent afternoon milking sessions. Entrance into the milking parlor and the numbers of steps and kicks by cows while the milking person was attaching the milking cups, were recorded in six milking sessions. Flight responses in the pasture after milking were recorded over four days intermittently. The frequency of ‘looking up’ behavior weakly, but significantly correlated with flight starting distance (r = 0.10, P < 0.05), while the correlation with the number of step‐kicks during milking was not significant. As for productivity, lactation number (r = ?0.18, P < 0.001), milk yield (r = ?0.15, P < 0.001) and fat content (r = ?0.15, P < 0.001) were negatively correlated with the frequency of ‘looking up’ behavior. Age of cows was correlated with the frequency of ‘looking up’ behavior as well as lactation number (r = ?0.21, P < 0.001). Entrance order was positively correlated with the frequency of ‘looking up’ behavior (r = 0.15, P < 0.001). The ‘looking up’ behavior was observed more frequently in cows in their third or less lactation compared with cows which were in their fourth or greater lactation (P < 0.05). The lactation number of cows was correlated with their milk yield (r = 0.36, P < 0.001) and flight starting distance (r = ?0.21, P < 0.001). In conclusion, ‘looking up’ behavior shown by cows in the holding area before milking might be an indicator of low motivation for milking, mainly because of fear of humans, and an aversion to milking caused by insufficient experience in being milked.     

挤奶频率对奶牛生产性能的影响

文章介绍了挤奶频率对奶牛泌乳性能、繁殖性能、健康与福利等方面的影响。