A note on the design and testing of single teatcups for automatic milking systems

peer-reviewedIn automatic milking units single independent teatcups or shell/liner combinations are required. The milking characteristics of three designs of single-teatcup milking units were compared with a conventional milking unit in a pipeline milking system. The combined weight of each single-teatcup shell and liner used in the single-teatcup units was 0.18 kg, 0.38 kg or 0.56 kg. The conventional milking cluster had a claw volume of 150 mL and a weight of 3.16 kg. The single sets of teatcups were applied manually and removed automatically when milk flow from the four teatcups reached 0.2 kg/min. The experiment involved a latin square design with four groups of Friesian cows (10 cows/group), four 2-day periods and four treatments. At a flow rate of 4 L/min during simulated milking the mean vacuum level at the teat-end (artificial teat) during the “bphase” of pulsation was 43.8 kPa with the conventional milking unit and 33 kPa for the three single-teatcup units. The corresponding mean and minimum teat-end vacuum in the “d-phase” were 38.46 kPa and 29.54 kPa, respectively, for the conventional system and 24.95 kPa and 17.59 kPa, respectively, for the single-teatcup configuration. The light teatcup (weight 0.18 kg) gave longer time to milk letdown, longer milking time and both lower peak and average milk flow than the conventional cluster

Evaluation of Milking Systems in Terms of Mastitis Risk, Teat Tissue Reactions & Milking Performance.

End of Project ReportsMeasurements of milking vacuum recorded on a flow simulator can provide guidelines for optimum design of milking units. • Increasing the bore of the short milk tube above the recommended diameter or claw volume above 150ml does not improve milking efficiency. • Increasing the long milk-tube bore from 13.5mm to 16mm increased the level of milking vacuum. • The milking vacuum was highest with wide-bore tapered liners and simultaneous pulsation. • The minimum vacuum was increased with narrow-bore liners and alternate pulsation. • The milk yield with wide-bore tapered liners in heavy 3-kg clusters and using simultaneous pulsation was 5% higher than with light clusters (1.65 kg) with alternate pulsation. • The milk yield depressions obtained with light clusters were similar in short and long term experiments and increased with the magnitude of the milk yield per milking. • The teat condition scores were not affected by the magnitude of vacuum fluctuations

A study of the somatic cell count (SCC) of Irish milk from herd management and environmental perspectives

End of project reportThe objective of this study was to investigate the herd management practices associated with somatic cell count (SCC) and total bacteria count (TBC), to geographically analyse SCC on a national basis, to investigate cow factors associated with SCC and to estimate the milk loss associated with high SCC across parities. From the 400 farms surveyed during farm visits throughout spring and winter, a profile of herd management was developed and the associations between management practices and milk SCC and TBC were established. Management practices associated with low SCC included the use of dry cow therapy, participation in a milk recording scheme, the use of teat disinfection post-milking, a higher frequency of cleaning and increased farm hygiene. Management practices associated with low TBC included the use of heated water in the milking parlour, participation in a milk recording scheme, tail clipping of cows at a frequency greater than once per year and increased farm hygiene. The spatial analysis showed that the south of the country had the greatest density of milk-recording herds. Approximately 60% of all herds in the study were from four counties (Cork, Kerry, Limerick and Tipperary). Average bulk tank SCC increased from 110,264 cells/mL in 2003 to 118,782 cells/mL in 2005, followed by a decrease to 108,454 cells/mL in 2007. Spatial clustering of high SCC scores was not observed (i.e., SCC on one farm was not related to SCC on other farms), which is consistent with mastitis being a herd problem as opposed to an area-based problem. SCC increased with parity from 97,000 cells/mL in parity 1 to 199,000 cell/mL in parity 6. SCC decreased between the period 5 to 35 days in milk (DIM) and 36 to 65 DIM, and increased thereafter. Cows calving in the months of January and September were associated with lower average 305 day SCC. The rate of increase in SCC from mid to late lactation was greatest in older parity animals. There was a test day milk loss of 1.43, 2.08, 2.59, 2.56 and 2.62 litres (parities 1 to 5, respectively) associated with an increase of SCC category from 400,000 cells/mL. When SCC was adjusted (test day SCC/dilution estimate, and test day SCC + (-ß)(test day milk yield)) to account for milk yield, similar trends in milk loss were observed. Alternatively, adjusting SCC (SCC*test day milk yield/mean test day milk yield) to account for milk yield showed an increase in test day milk with increasing SCC category. The results from this study highlight that adherence to best milking/farming practice will help reduce SCC and TBC on farms. The results contribute to the knowledge relating to SCC through increasing the accuracy of milk loss due to SCC and management practices associated with SCC. The results in the study can also be used in the development of strategies to reduce SCC on farms

A study of factors affecting the efficiency of milking operations.

End of Project ReportWith a mid-level milking system the milking time was reduced significantly when the teat end vacuum was increased • Vacuum losses were lower and milking time was shorter with simultaneous pulsation than with alternate pulsation • Milk yield was not affected by the magnitude of teat end vacuum. • Both the mean flowrate and peak flowrate increased when the teat end vacuum was increased. • New milking plants and conversions should have 16 mm bore long milk tubes (LMT) and 16 mm bore entries in the milk pipeline • The omission of udder washing as a pre-milking preparation procedure did not influence milking characteristics. • TBC and E. coli were significantly reduced with full pre-milking preparation compared to no pre-milking preparation when milk was produced from cows on pasture • Counts for individual bacterial species were well below maximum numbers permitted in EU Council Directive (Anon. 1992) when no pre-milking preparation was carried out

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

peer-reviewedFriesian-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

Design of automatic milking system for use in pasture-based systems

End of Project ReportA commercial vision system was successful in identifying target artificial teats in various and demanding scenarios, but the system is very prone to making false identifications. A robotic manipulator capable of the simultaneous handling of four milking cups has been designed. The end-effector profile is sufficiently compact to allow access between the rear legs of the cow while enabling full access to all four teats for application of milking cups. The positioning response of the end-effecter is satisfactory for accommodating small changes in teat position during milking cup application

Note on a portable simulator for analysis of milking machine porformance

peer-reviewedA portable flow simulator was developed for recording vacuum variations in commercial milking machine clusters. The cluster in the milking unit under evaluation was mounted on the frame of the simulator and the flow of water through each liner was regulated by separate flow meters. By placing an artificial teat into the liners the flow characteristics during actual milking were simulated. Measurement vacuum sensors were mounted in the claw, in one artificial teat, in the pulsation chamber and in the milk pipeline. Analog and digital outputs were recorded. The system was validated by comparing the outputs with those obtained with a laboratory flow simulator and with recordings taken during cow milking. The recordings with the portable simulator and the laboratory simulator were identical; the profiles of the analogue signals obtained with the portable simulator and from cow milking were similar. The portable flow simulator will allow recording of vacuum variations in commercial milking machines during simulated or actual milking.European Unio

Effects of the design of a milking unit on vacuum variations during simulated milking

peer-reviewedThe vacuum variations at the apex of an artificial teat during simulated milking were measured in a factorial-design laboratory test involving six cluster types, two internal diameters (13.5 mm and 16 mm) of long milk tube (LMT), three water flow rates (4, 6 and 8 l/min), simultaneous (4 × 0) and alternate (2 × 2) pulsation patterns and three pulsator ratios (60, 64, and 68%). Four of the six clusters were fitted with wide-bore tapered liners and represented all combinations of two claw volumes (150 or 420 ml) and two short-milk-tube bores (8.5 mm and 13.5 mm). Two clusters were fitted with narrow-bore liners (22 and 25 mm) that had large-bore short milk tubes and large claw volumes. The vacuum variations were expressed as mean vacuum at the teat-end during the b-phase of pulsation (TVB), mean vacuum at the teat end measured over complete pulsation cycles (TV), minimum vacuum measured over complete pulsation cycles (TVM) and amplitude of vacuum fluctuation measured over complete pulsation cycles (TVF). The highest level of TVB was recorded with wide-bore tapered liners. For a milking unit fitted with a wide-bore tapered liner TVF was reduced and TVM increased by increasing either the bore of the short milk tube or the volume of the claw. When the bore of the LMT was increased TVB, TV and TVF increased. Simultaneous pulsation gave higher TVB (P < 0.001) and higher TVF (P < 0.001) than alternate pulsation for all cluster types. The overall effects of altering pulsator ratio were significant but small in practical terms. There were significant interactions between cluster type and water flow rate and pulsation pattern for TVB, TV, TVM and TVF.European Unio

A note on the effects of test-end vacuum on milking characteristics

peer-reviewedThe magnitude of vacuum applied to the teat end can have a major effect on milking characteristics. While milking vacuum is usually measured in the milk pipeline, the teat-end vacuum during milk flow depends on the configuration of the milking unit. The objective was to establish the effect of teat-end vacuum, recorded during flow simulation, on actual milking time, milk yield, and both mean and peak milk-flow rates. Four configurations of milking units were set up to give vacuum levels of 35, 38, 40 and 42 kPa at the apex of an artificial teat during simulated milking. The experiment involved a latin square design with four groups of Friesian cows (14/group), four 2-day periods and four treatments (vacuum level). Altering the vacuum level had no significant effect on milk yield. There were no differences in milking characteristics between vacuum levels of 38 and 40 kPa. A vacuum level of 42 kPa gave a shorter milking time (P < 0.001), higher average milk-flow rate (P < 0.01) and higher peak milk-flow rate (P < 0.001) than the three lower vacuum levels. Milking time was significantly longer (P < 0.001) and peak milk-flow rate lower (P < 0.001) with a vacuum of 35 kPa compared to other vacuum levels

The involvement of astrocytes in early-life adversity induced programming of the brain

Early-life adversity (ELA) in the form of stress, inflammation, or malnutrition, can increase the risk of developing psychopathology or cognitive problems in adulthood. The neurobiological substrates underlying this process remain unclear. While neuronal dysfunction and microglial contribution have been studied in this context, only recently the role of astrocytes in early-life programming of the brain has been appreciated. Astrocytes serve many basic roles for brain functioning (e.g., synaptogenesis, glutamate recycling), and are unique in their capacity of sensing and integrating environmental signals, as they are the first cells to encounter signals from the blood, including hormonal changes (e.g., glucocorticoids), immune signals, and nutritional information. Integration of these signals is especially important during early development, and therefore we propose that astrocytes contribute to ELA induced changes in the brain by sensing and integrating environmental signals and by modulating neuronal development and function. Studies in rodents have already shown that ELA can impact astrocytes on the short and long term, however, a critical review of these results is currently lacking. Here, we will discuss the developmental trajectory of astrocytes, their ability to integrate stress, immune, and nutritional signals from the early environment, and we will review how different types of early adversity impact astrocytes