Milk Meters Research Articles

Effects of intramammary infections on somatic cell score and milk yield in Sarda sheep

AIM: To evaluate the effects of intramammary infections (IMI) on somatic cell score (SCS) and milk yield in dairy ewes. METHODS: Monthly milk samples were collected from a flock of 202 Sarda sheep, over a period of 7 months, for bacteriological culture and measurement of somatic cell counts (SCC). During the same period, milk yield was measured daily using electronic milk meters connected to each half-udder cluster of the milking machine. SCC was transformed to SCS using a base-2 log transformation. One SCS is equivalent to a SCC of 25,000 cells/ml, and each increase of 1 in SCS is associated with doubling of the SCC. IMI was defined by the presence of five or more colonies of similar morphology isolated from a milk sample (≥500 cfu/ml). The effect of IMI on SCS and milk yield was assessed using a generalised estimating equation (GEE). RESULTS: There were 1,186 udder halves with IMI from 2,828 milk samples, a prevalence of 41.9%. The distribution of bacterial species within the 1,186 culture-positive samples was comprised of 476 (40.1%) Staphylococcus epidermidis, 172 (14.5%) Staph. chromogenes, 38 (3.2%) Staph. caprae, 134 (11.3%) Staph. simulans, 114 (9.6%) Streptococcus uberis, 123 (10.4%) Strep. dysgalactiae, and 129 (10.9%) Strep. equi subsp. zooepidemicus. SCS was greater in udder halves with IMI (mean 7.71; SD 0.82) than in udder halves without IMI (mean 5.53; SD 1.02) (p<0.01). IMI due to streptococcal species were associated with greater SCS (mean 8.24; SD 0.62) than those due to staphylococcal species (mean 7.48; SD 0.79) (p<0.01). Milk yield from udder halves with IMI was lower (mean 439 (SD 162) ml/half udder/day) than from udder halves without IMI (mean 602 (SD 170) ml/half udder/day) (p<0.01). IMI due to staphylococcal species was associated with a lower milk yield (mean 399 (SD 167) ml/half udder/day) than IMI due to streptococcal species (mean 427 (SD 156) ml/half udder/day) (p<0.01). CONCLUSIONS: These findings provide sheep milk producers with information on the losses associated with subclinical mastitis, which can be used to evaluate the economics of prevention and treatment protocols concerning udder health in ovine dairy flocks.

Milkability assessment of Tsigai, Improved Valachian, Lacaune and F1Crossbred ewes (Tsigai × Lacaune, Improved Valachian × Lacaune) throughout lactation

This paper aimed to compare the milking ability of ewes from pure European breeds (Tsigai, Improved Valachian, Lacaune, and their crosses) on the basis of their milk flow kinetics during machine milking throughout lactation. Ewes of the Tsigai (TS, n = 13), Improved Valachian (IV, n = 12), Lacaune (LC, n = 12), TS × LC (50%, n = 12) and IV × LC (50%, n = 12) on their 1–3 lactation were used. The ewes were in their 74 ± 12 d of lactation at the beginning of the experiment. Milk flow data of each ewe were recorded during one evening milking in the middle of four successive months (May, June, July, and August). Milk flow was recorded by means of an automatic collecting jar equipped with an electronic milk meter device working in every 1-s intervals. The milk flow curves were classified into three types: 1 peak (1P), 2 peaks (2P) and plateau (PL). The highest values of repeatability of parameters were found for stripped milk yield (SMY), maximum milk flow, latency time and milk yield at 30 s (over 0.52). The lowest values were recorded for machine milking time (MMT), machine milk yield (MMY) and time to reach maximum milk flow (<0.33). Month of lactation significantly influenced most of the milkability data except latency time and time to maximum flow rate. The effect of genotype showed highly significant influence on most of the analyzed parameters. The lowest total milk yield (TMY) and MMY were measured in pure TS (0.348 ± 0.02 l and 0.266 ± 0.021 l, respectively) and IV breeds (0.320 ± 0.022 l and 0.259 ± 0.021 l, respectively) as compared with Lacaune (0.524 ± 0.022 l and 0.360 ± 0.021 l, respectively). The highest TMY and MMY were measured in ewes with PL milk flow types and the lowest in ewes with 1P. Ewes with 1P showed clearly shorter MMT and higher percentage of SMY as compared to PL and 2P though SMY did not differ among groups. Interaction of milk flow type and stage of lactation influenced TMY and MMY, maximum milk flow, milk yield in 30 s of milking and MMT. A clear effect of milk flow type on TMY and MMY was observed each month.

Biofilm in milking equipment on a dairy farm as a potential source of bulk tank milk contamination with Listeria monocytogenes

The objective of this study was to assess the presence of a Listeria monocytogenes-containing biofilm in milking equipment as a potential source of bulk tank milk contamination on a dairy farm where milk contamination had been previously documented. Samples were collected from milking equipment and milking parlor premises on 4 occasions and analyzed for the presence of L. monocytogenes. Pulsed-field gel electrophoresis (PFGE) typing was conducted on L. monocytogenes isolates from the milking equipment, parlor and storage room floors, bulk tank milk, and in-line milk filters. Pieces from milk meters and rubber liners were obtained to visually assess the presence of a biofilm using scanning electron microscopy. A total of 6 (15%), 4 (25%), and 1 (6%) samples were culture-positive for L. monocytogenes in the first, second, and third sample collection, respectively. Two samples were L. monocytogenes hly PCR-positive but were culture-negative in the fourth sample collection. Combined AscI and ApaI restriction analysis yielded 6 PFGE types for 15 L. monocytogenes isolates obtained from milking equipment, parlor, bulk tank milk, and milk filters. A predominant and persistent PFGE type (PFGE type T) was observed among these L. monocytogenes isolates (9/15 isolates). Scanning electron microscopy of samples from the bottom cover of 2 milk meters showed the presence of individual and clusters of bacteria, mainly associated with surface scratches. The presence of a bacterial biofilm was observed on the bottom covers of the 2 milk meters. Prevention of the establishment of biofilms in milking equipment is a crucial step in fulfilling the requirement of safe, high-quality milk.

Effect of the sampling device on fat and protein variation in cow milk samples obtained for official milk recording

The paper was designed to assess the effect of the type of milk meter used by dairy farms for official milk testing to obtain individual milk samples for fat and protein determination. This study was performed in 2006 in Galicia, which is Spain's main dairy cattle region; data were collected from 2,149 Holstein cow farms enrolled for official milk recording. Findings indicate that the milk sampling system used has a substantial effect on the fat contents recorded for individual milk samples. Such variation could arise from poor functioning of the equipment, inadequate mixing of the milk portion from which the sample is obtained, or from the nonproportionality of the sample. Samples obtained from only one point in the milk line may not be representative of all the milk produced. The most significant differences are observed in the percentage of fat, whereas differences in percentage of protein are smaller. The sampling method used should, but does not always, provide a representative sample of the milk from a single milking.

Development and testing of a “free-flow” conductimetric milk meter

Accurate milk yield measurement is important to maintain production efficiency and improve farm management: yield data enable to implement and evaluate feed rations for individual cows or groups, calculate actual lactation curves and identify potential health problems proactively. Nowadays, many electronic milk metering devices, based on different methods of measurement, are available on the market. Vacuum drop across the meter, accuracy over a wide range of flow rates and farm conditions (e.g. foaming of milk) are the key problems of currently available electronic milk meters. Aim of this project was the development of a free-flow milk meter, able to work with different flow rates and different combination of air-milk flows, with a measuring chamber essentially made by a portion of linear pipe, horizontally disposed and with no mechanical movement parts, to minimize the interferences with the milk flow and on the electric conductivity (EC), to calculate the milk yield, in order to obtain a low-cost device. A prototype was built up and laboratory and farm tests were carried out during 2004 and 2005, in order to evaluate the accuracy and reproducibility of the new device. Laboratory and farm tests were carried out following the guidelines of the International Committee for Animal Recording (ICAR). Laboratory tests showed a bias of 1.4% and a standard deviation of 5.0%, while farm tests showed a bias of −4.5% and a standard deviation of 12.7%.

An investigation into the relationship between milk progesterone concentrations in fore-milk and composite milk samples

AbstractMilk progesterone concentrations are generally estimated on a composite, “jar”, sample from the bulk milk collecting jar, with concentrations &gt;3 ng/ml considered as indicative of the presence of luteal tissue. However, on a number of dairy farms composite sampling is not possible as they operate a direct pipeline milking system, without milk meters, and the only practical means of obtaining a milk sample is via fore-milk sampling. The objective of this study was to investigate the relationship between progesterone concentrations, as estimated by an ELISA procedure, in fore-milk strippings and composite milk samples. A significant relationship (r2 = 0.83) was obtained between the progesterone concentration in composite milk and fore-milk samples; y = 1.52 - 1.41(0.163)x, where y = log10(composite progesterone) and x = log10(fore-milk progesterone). A milk progesterone concentration of 3 ng/ml in composite milk corresponded to a milk progesterone concentration of 1.47 ng/ml in fore-milk. Using this relationship progesterone profiles may be compared between herds where milk samples have been obtained by either composite milk or fore-milk sampling. In addition, composite milk samples only should be used with qualitative on-farm assays.

Introduction of electronics into milking technology

In countries, like the former German Democratic Republic (GDR), where ‘industrialized’ milk production in large herds was the goal to be reached, research on automation of machine milking was started more than 30 years ago. Initially, the main goal was to mechanize operations at the end of the milking process. This work finally resulted in milking devices that do not apply uniform parameters to all cows, but operate according to the milk flow obtained from the cow actually to be milked. This evolution towards ‘controlled milking’ would not have been possible without application of electricity and electronic components for sensors and control units. Also depending on the technical evolution of electronic control systems are devices for recording milk yield and for taking samples for milk analysis, which were available around the year 1980. At that time initial projects for automatic milk recording were evaluated, which had an obvious influence on further development of milk meters. The most demanding step of application of electronic control systems up to now was the introduction of automatic milking systems. Here not only application of teat cups has to be executed, it also is necessary to enable automatic checks of udder condition, milk quality and other operations which may be challenging even for trained human operators. Further evolution of electronic measurement procedures may be important for the milk-producing farmer too, especially when on-line milk analysis is to be introduced within the near future.

Within milking variation of urea, acetone, fat and protein and the determination of sampling time for an on-line system

Sampling for analysis of milk constituents (fat and protein) is a routine procedure on commercial dairy farms. It is assumed that for this procedure a representative sample of whole milk is taken, either as a fractionated sample from the milk meter or as a thoroughly mixed milk sample taken after the milk has been agitated with air in the recording jar. The use of on-line sensors for milk analysis will provide real-time data on which nutritional management decisions can be made according to milk composition. However, there is no recommendation as to the optimum sampling time in an on-line system to obtain a representative sample during the milking process. Ideally sampling should be carried out as early as possible for the analysis to be completed before the milking system is needed for the next cow. It is important to establish within milking variation of milk constituents for an on-line sensing system, especially since fat increases significantly throughout milking. The aims of this study were to determine the within milking variation of urea, acetone, fat and protein and to specify the most appropriate time of sampling within milking to obtain representative concentrations of these constituents and analytes.

Near infrared spectroscopy for biomonitoring: cow milk composition measurement in a spectral region from 1,100 to 2,400 nanometers.

The potential of near infrared spectroscopy (NIRS; 1,100 to 2,400 nm) to measure fat, total protein, and lactose content of nonhomogenized milk during milking and the influence of individual characteristics of each cow's milk on the accuracy of determination were studied. Milk fractions were taken during milking, twice per month, for 6 mo. Samples were taken every 2nd and 4th wk at the morning and the evening milkings. Teatcups were removed at each 3 L of milk yield as determined with a fractional sampling milk meter. A total of 260 milk samples were collected and analyzed with an NIRSystem 6500 spectrophotometer with 1-mm sample thickness. Partial least squares (PLS) regression was used to develop calibration models for the examined milk components. The comparison with the reference method was based on standard error of cross validation (SECV). The obtained SECV varied from .107 to .138% for fat content, from .092 to .125% for total protein, and from .066 to .096% for lactose content, and the accuracy of the reference method (AOAC, 1990, method No 972.16) was .05% for all measured milk components. The obtained models had lower SECV when an individual cow's spectral data were used for calibration. The reduction of SECV for each cow's individual calibration, when compared with SECV for the set of all samples, differed with the different constituents. For fat content determination, the reduction reached 22.46%, for protein 26.40%, and for lactose 31.25%. This phenomena was investigated and explained by principle component analysis (PCA) and by comparing loading of PLS factors that account for the most spectral variations for each cow and the measured milk components, respectively. The results of this study indicated that NIRS (1,100 to 2,500 nm, 1-mm sample thickness) was satisfactory for nonhomogenized milk compositional analysis of milk fractions taken in the process of milking.

Measurement of Liner Slips, Milking Time, and Milk Yield

Liner slip or rapid air leakage past the mouthpiece of the milking machine liner is related to high rates of new cases of mastitis. A real time technique was developed to monitor the air flow into the milking machine cluster during liner slips as well as to monitor milking time and milk yield using a commercial type pipeline milking system. The air flow into the cluster was measured by recording the pressure differences across on orifice plate place in the air bypass of an air-milk separator using a differential pressure transducer. Milk yield was recorded by counting the number of milk releases from an electronic milk meter. The release solenoids of the milk meter were linked to a computer. The start and end of milking were manually recorded by switching a twopole switch connected to a digital input card on the computer, which was programmed to record air flow, milk yield, and milking time. Milk yield, milking time, and air flows during liner slips were recorded simultaneously at each milking unit in an 11-unit herringbone parlor. The system was tested with an experiment with a 4 × 4 Latin square design using four treatments (clusters) and four treatment groups (22 cows per group).

Dairybase: An Electronic Individual Animal Inventory and Herd Management System

A microcomputer application program developed with database management system technology is described for management of animal inventory, reproduction, genetic improvement, feeding, milk production, and health records of dairy cattle. An inventory of cattle, frozen semen, frozen embryos, and nutrient content of feeds is maintained in integrated databases using a relational database management system. Knowledge-based management information is encoded into the application program to enhance management. The program utilizes electronic transfer of milk production data from electronic milk meters and has the capability to minimize manual entry of other data by electronic updating of the database. Use of the program in a 300-cow herd enhanced the detail of data available for management of individual cows and provided an improved method for planning herd management events, monitoring the current status of individual cows, and custom interfacing herd records with new or emerging electronic communication and animal sensor technology.

Investigations on the design of floats to control milk meters

To reduce the influence of variable density of milk on the accuracy of volumetric milk meters, equipped with floats, the amount of air in the milk at float level was measured and the effect of geometry and specific gravity of floats on the accuracy of two volumetric milk meters was estimated. The influence of milk density on meter operation was lower when the float was placed in a measuring chamber after separation of air and milk in an inlet chamber. Best results were obtained using a float with a specific gravity of 0.724 g/cm3. A float with a long vertical axis, a cone-shaped upper portion and a specific gravity close to 0.5 g/cm3 was least affected by variable density of the fluid when operating in unseparated air and milk.

Physiological, Productive, and Economic Benefits of Shade, Spray, and Fan System Versus Shade for Holstein Cows During Summer Heat

During the 1984 summer, effects of spray and fan in freestall areas and feeding areas on milk yield, plasma growth hormone and prolactin, freestall utilization, and economic significance for Holstein cows were studied. Weekly milk and rectal temperatures at morning and afternoon milkings were higher for cows in shade than in shade with spray and fan cooling. Compared with rectal temperature, milk temperature measured in the clawpiece provided a more reliable indicator of heat stress than in the milk meter. Diurnal pattern of rectal temperature from 4-h measurements showed an average of 12h in which maximal rectal temperatures of cows in shade were greater than 39°C, but cows in the shade plus spray plus fan group had rectal temperatures below 39°C all day. Plasma growth hormone was higher and prolactin lower for cows in shade plus spray and fan than cows in shade only.Cows cooled with spray and fan under shade produced 2 kg/cow per d more than cows in shade alone. Eeconomic analysis showed a net income of 22¢/cow per day for spray plus fan under shade. Results suggest that milk temperature is a practical technique to assess heat stress in dairy cattle, and the use of spray plus fan is a profitable means to maximize cow comfort and lessen stress-induced decline in milk production.

Rates of Milk Flow and Milking Times Resulting from Selection for Milk Yield1,2

Responses to selection for milk yield for rates of milk flow and times for milking were studied using data from an experimental herd of Holsteins. In 1964, foundation cows were paired by sire and randomly split into two genetic groups, selection and control. Four highest bulls for Predicted Difference milk were mates for selection cows each year and replaced annually. Twenty bulls near breed average for milk in 1964 were mated continuously to control cows. Beginning in 1972, milk yield at 15-s intervals was recorded by using a stopwatch and milk meter. Lactations for 130 selection and 162 control cows were observed over 10 yr. Selection cows did not differ from controls during first lactation for rate of milk flow but took longer to milk until stripping. When adjustment was made for milk yield at the observed milking, pedigree groups did not differ for milking time until stripping. Data from all cows suggested that rates of milk flow were also greater for selection cows. First parity heritabilities were .46 (peak rate), and .68 (milking time until stripping). Genetic and phenotypic correlations of milk yield with rates of flow and milking times were positive.

Milk Iodine Residues in Herds Practicing Iodophor Premilking Teat Disinfection

The objective was to determine effects of different concentrations of iodophor teat dips on milk iodine residues, when teat dips were used both premilking and postmilking. Eighty cows in each of seven herds were assigned to one of four treatments. Each treatment received postmilking teat dip at .1 or 1% iodophor concentration. Two groups received no premilking dip, and the other two groups received premilking teat dip at the same concentration as the postmilking teat dip. Premilking teat dipping was followed by manual drying of teats. Noniodophor postmilking dips and no premilking inodophor udder sanitizers were used during an 8-d adjustment period. Milk was collected for milk iodine determination from each cow from weigh jars or milk meters at p.m. milkings during the last 3 d of the adjustment period and d 4, 6, and 8 of the treatment period. Premilking and postmilking teat dipping with .1% iodophor dip did not significantly increase milk iodine residue above postmilking teat dipping with .1% iodophor dip alone. However, 1% iodophor postmilking teat dip significantly increased milk iodine residue over use of .1% iodophor dip used as a premilking and postmilking teat dip. Adding a 1% iodophor premilking teat dip significantly increased iodine residues.

Changeover from dipstick measurement to metered collection of ex‐farm milk in England and Wales

The introduction of systems for the collection of milk from farms in England and Wales using tanker‐mounted turbine milk meters, and the arrangements for driver training and the servicing and calibration of meters, are described.

A capacitor milk meter for data logging

Abstract A commercial milk meter has been modified to give an electrical output suitable for data logging by attaching two strips of metal foil to the outside of the measuring cylinder to form a capacitor. A 5 MHz oscillator supplies a voltage divider circuit consisting of the milk capacitor and a low-value resistor in series. When milk rises in the cylinder the capacitance increases, a dicde circuit changes the alternating voltage to direct voltage, and this is displayed on a digital voltmeter which is used to control a tape punch. Alternatively, the change in capacitance may be used to give a frequency-modulated output.