Stripping Milk Research Articles

Effect of dynamic pulsation and milk flow rate switch-point settings on milking duration and post-milking teat condition.

The objective of this study was to investigate the effect of dynamic pulsation settings that increased the open phase and reduced the closed phase of pulsation during the peak milk flow period together with increasing the milk flow rate switch-point for cluster detachment on milking duration and teat condition after milking. The present study filled current gaps in knowledge by informing on the effects of both milk flow rate switch-points and dynamic pulsation together in one experiment, while presenting data on milking performance, strip milk, teat condition and vacuum levels in the cluster during milking. To this end, 4 treatments consisting of different milk flow rate switch-points and pulsator settings combinations were deployed across 4 groups of 24 cows for 8 weeks. Treatments consisted of 2 levels of milk flow rate switch-point (0.2 kg/min and 0.8 kg/min) and 2 pulsator settings (static and dynamic). The static pulsator settings had a pulsator ratio of 65:35. For the dynamic settings a pulsator ratio of 63:37 below a milk flow rate of 2 kg/min was used, which changed to 73:27 above 2 kg/min. Milking parameters and teat scoring data were analyzed using mixed models. The effect of milk flow rate switch-point on milking duration was significant, whereas the effect of dynamic pulsation was not. The reductions in milking duration were larger for PM milking (for static pulsation settings, the average reduction was 21% between switch-point of 0.2 kg/min and 0.8 kg/min) compared with a 12% reduction for AM milking. In addition, we found a significant effect of treatment on teat-barrel congestion, with reduced odds of teat-barrel ringing for treatments with a milk flow rate switch-point of 0.8 kg/min relative to 0.2 kg/min due to significantly reduced over milking time and hence reduced exposure to higher mouthpiece chamber vacuum during the over milking period. On average across all treatments cows spent 32% of the milking above 2 kg/min, however this varied from 37% for AM milking to 23% on average for PM milking, hence an uneven milking interval impeded the ability of dynamic pulsation to contribute, especially for PM milking. We concluded that milk flow rate switch-point settings are more impactful than dynamic pulsation settings for reducing milking duration. Furthermore, we found no evidence of interactions between the effects of switch-point and pulsator setting on milking duration, milk yield or milk flow rate.

Dam–calf contact rearing in Switzerland: Aspects of management and milking

Cow-calf contact (CCC) rearing is becoming an increasingly popular alternative to the common practice of early separation of cow and calf in dairy management. Milkability can be impaired in nursing cows, which contributes to the loss of machine milk yield caused by calf intake, especially in pure dam-calf contact (DCC) systems. The aims of this study were (1) to describe the current status quo of DCC rearing regarding management and milking and (2) to evaluate the effects of DCC (suckling and milking vs. milking alone) and the effects of different types of DCC on milkability parameters, teat condition, and behavior during milking on Swiss DCC farms. By means of 17 telephone interviews with DCC farmers, we collected data on DCC management, housing, separation and weaning processes, milking procedures and techniques, and perceived milkability problems. Subsequently, we collected data on 10 of the interviewed DCC farms (183 cows): 4 DCC farms with a whole-day contact (WDC) system, 3 farms with DCC before milking (CBM), and 3 farms with DCC after milking (CAM). Five farms on which calves had no contact with dams were chosen as reference farms (178 cows). Using a milk flow meter, the occurrence of ejection disorders, bimodality of the milk flow curve, machine milk yield, duration of the decline phase, and duration of prestimulation were measured. The average mouthpiece chamber vacuum during the main milking phase and hind leg activity during milking were measured using a pressure sensor and an accelerometer, respectively. After cluster removal, the teat condition was evaluated, and a stripping milk sample was taken for fat content analysis. The interview results revealed that 8 of the 17 farms surveyed had a WDC system, and 2 farms operated a daytime DCC system. Contact before milking was applied by 3 farms, and 3 farms allowed CAM. On one farm, calves had access to dams 3 times a day. A great diversity in cow-calf management was found. In the on-farm data collection, 20 milkings of a total of 701 milkings examined met the criteria for a clear ejection disorder, with 17 of these observations occurring on WDC farms and none on reference farms. The stripping milk fat content was lower in nursing cows, indicating a lower degree of udder emptying. Machine milk yield was higher in nursing CAM cows than in nursing WDC and CBM cows. Farm types did not differ regarding teat condition, hind leg activity, or the occurrence of bimodal milk flow curves. In conclusion, the large variation in individual management approaches to DCC rearing even within DCC types, such as calf housing or cow breeds, implies caution when interpreting results. Contact after milking may be the system most beneficial for some productivity parameters, but adequate calf supply must be ensured. Higher amounts of milk remaining in the udder after cluster removal indicate that nursing can affect milkability, but future research should consider the effects of udder filling before milking to better interpret the fat content of stripping milk.

Estimation of udder emptying based on milk constituents of strip samples after milking

Milk ejection disorders were induced by oxytocin receptor blockade. We tested the hypothesis that the degree of udder emptying at incomplete milk ejection can be estimated based on the concentration of various milk constituents in different milk fraction samples. To induce different levels of spontaneous udder emptying (SUE) 10 Holstein dairy cows were milked either with or without i.v. injection of the oxytocin receptor blocking agent atosiban (ATO). In ATOearly, 12 µg/kg BW ATO was injected immediately before and in ATOlate directly after a 1-min manual udder preparation. The normal milking routine served as the control treatment. In all 3 treatments the udder was completely emptied by the i.v. injection of 10 IU oxytocin (OT) at the end of spontaneous milk flow. During all experimental milkings 4 milk samples were taken in all treatments: at the start of udder preparation (foremilk; FM), immediately after cessation of spontaneous milk flow and cluster detachment by hand stripping (strip milk; SM), from spontaneous removed milk in bucket 1 (milk before OT; MBOT) and from the milk obtained after OT injection in bucket 2 (milk after OT; MAOT). Fat, protein, lactose, and electrolytes (Na, Cl, and K) were measured in each milk sample. In addition, electrical conductivity (EC) was determined in parallel to continuous milk flow recording. The treatments induced individual degrees of SUE; therefore, the final evaluations of data were based on SUE classes instead of treatments. The most pronounced differences of milk constituents at different degrees of SUE were found for the milk fat content. The fat content of SM and MBOT remained almost unchanged up to 60% SUE, but was considerably higher if >80% of the milk was spontaneously removed. The concentrations of Na and Cl were highest and of K lowest if less than 20% of milk was received in the different samples. The EC was higher in SM and MBOT if <20% of milk was received. In conclusion, the blockade of the OT effect influences primarily the fat content, which confirmed an OT-induced fat secretion during milking. Similar effects are likely found in situations of disturbed milk ejections, caused by a lack of or reduced release of OT in response to different degrees of tactile udder stimulation. Our results show that the measurement of fat content and the EC in SM samples collected after cluster detachment can be used to estimate the completeness of udder emptying.

Effect of milk flow-rate switch-point settings on milking duration and udder health throughout lactation

The objective of this study was to quantify the effects of different milk flow-rate switch-point settings on milking duration, SCC, strip milk, teat condition and milk yield in a grass based system in a long-term experiment. Much work has already been conducted providing strong support for significant reduction in milking duration without impact on yield through increasing the flow-rate switch-point at which vacuum to the milking cluster ceases and the cluster is removed from the cow by means of a retracting cord. However, in practice many farms have not adopted this labor saving technology on the basis that it may increase milk SCC. Recent research on commercial Irish dairy herds identified the contagious mastitis causing pathogen Staph. aureus as the most prevalent pathogen detected. Staph. aureus could have a cyclical shedding pattern which would inhibit detection at certain time points. Therefore, to reliably assess the effect of milk flow-rate switch-points on SCC, a long-term study was required, consisting of multiple observations on cow level SCC. The present study filled this gap in knowledge by informing on any impact that ceasing milking at different flow-rates may have on milking duration and SCC levels, particularly with regard to spring calving grass based systems. Four treatments, consisting of milk flow-rate switch-points increasing from 0.2 kg/min to 0.8 kg/min in steps of 0.2 kg/min, were deployed for 31 weeks to cows at the Teagasc Research Centre at Moorepark, Ireland. The effect of treatment on daily milking duration was significant (P < 0.001). The milking duration for a milk flow-rate switch-point of 0.8 kg/min was 95 s (14%) shorter than for 0.2 kg/min. We did not find a significant effect of increasing the milk flow-rate switch-point from 0.2 to 0.8 kg/min on milk yield or SCC in this long-term study. We did find a significant effect of week of experiment on milk SCC, whereby the SCC of the cows on the experiment increased similarly among treatment groups as lactation progressed. A significant reduction in Dead Time (time from cluster attachment to reach a milk flow-rate of 0.2 kg/min) was also noted as the milk flow-rate switch-point increased. On average reductions in Dead Time contributed 12% to the overall reductions in Milking Duration. Similarly, reductions in Low Flow Time (time from a flow-rate of 0.2 kg/min to cluster detachment at the end of milking) contributed 26% to the overall reductions in Milking Duration. Reductions in Dead Time and Low Flow Time played a greater role in reducing PM Milking Duration rather than AM Milking Duration due to the milking interval practiced on the research farm.

Effects of short and long milking intervals on milking characteristics and changes of milk constituents during the course of milking in crossbred Istrian × Awassi × East-Friesian ewes.

The main objective of this experiment was to evaluate the effects of two milking intervals (8 and 16 h) on milk constituents (fat, protein, lactose, dry matter, and log10 SCC) of nineteen Istrian × Awassi × East-Friesian crossbred ewes in different milk fractions (0-25, 25-50, 50-75 and 75-100%) during the course of milking and in machine stripping (MS) milk. Furthermore, we sought to determine the effect of the two milking intervals on milking characteristics (average milk flow rate, peak milk flow rate, machine-on time, total milk yield, and milk production rate) and whether each milk constituent within each milking interval is best described by a linear, quadratic, or cubic function. Average milk flow rate and milk yield per milking decreased in the 8 h milking interval compared to the 16 h milking interval (P < 0.05). Peak milk flow rate, machine-on time, and milk production rate were not different between the two milking intervals. Overall, milk fat content, dry matter content, and log10 SCC increased in the 8 h milking interval compared to the 16 h milking interval (P < 0.05). Milk protein content did not change through the main milk fractions at either milking interval. Milk lactose content did not change through the milk fractions at the 8 h milking interval, whereas it decreased in the 75-100% and stripping milk fractions at the 16 h milking interval (P < 0.05). The 0-25% and stripping milk fractions contained the highest log10 SCC compared to all other milk fractions (P < 0.05). Changes of milk fat and dry matter content throughout milking were best described by quadratic functions, whereas milk protein content, milk lactose content, and log10 SCC were best described by different functions depending on the milking interval. These results demonstrate that milking interval influenced all milk constituents in various milk fractions during the course of ewe milking. Moreover, milking characteristics such as average milk flow and total milk yield, and the appropriate mathematical function to characterize milk constituents throughout a milking, were affected by milking interval.

Effects of simulated quarter and udder teat cup removal settings on strip milk and milking duration in dairy cows

The aim of this study was to estimate the amount of milk left in quarters and udders and the milking duration for a variety of teat cup removal strategies. A combination of empirical data and simulated quarter and udder teat cup removal settings were used to make these estimates. Milking duration is an important factor in both automatic and conventional milking systems because it directly influences milking efficiency and hence can affect farm profitability. Strategies investigated in the literature to reduce milking duration include the application of different milk flow rate switch-points (milk flow rate at which the milking unit or teat cup is removed). Applying these milk flow rate switch-points can affect the amount of milk that is not harvested (strip milk). We are not aware of previous research analyzing strip milk yield and milking duration at the quarter level, across a range of quarter and udder milk flow rate switch-points. Quarter-level average milking duration decreased by 2 min, and strip milk increased 1.3 kg as quarter milk flow rate switch-point was increased from 0.2 kg/min to 1.0 kg/min. Using an end of milking criterion of removal of the teat cup at 50% of the quarter's rolling average milk flow rate resulted in a 0.4-min reduction in milking duration and a 0.08-kg increase in strip milk per quarter, compared with removal of the teat cup at 30% of the quarter's rolling average milk flow rate. Udder-level average milking duration decreased by 1.4 min, and strip milk increased by 0.76 kg (0.19 kg per quarter) as udder milk flow rate switch-point was increased from 0.2 kg/min to 1.0 kg/min. A 0.8-min reduction in cow milking duration and a 0.27-kg increase in strip milk at the udder level (0.08 kg per quarter) resulted when changing udder milk flow rate switch-point from 30% of the udder rolling average to 50% of the udder rolling average milk flow rate. This study provides quantitative estimates of the effect of teat cup milk flow rate switch-points on milking duration and strip milk yield.

Milk electrical conductivity in Manchega ewes: Variation throughout milking and relation with mammary gland health status

The aim of this work was to study the effect of milking fraction and mammary gland health status on the electrical conductivity (EC) of milk from Manchega ewes, considering also the lactation number. To this end, we also studied the relationship of EC with milk macrocomposition, and the relation existing between EC and somatic cell count (SCC). Finally, the use of EC thresholds as a mastitis detection method (sensitivity, specificity, positive (PPV) and negative predictive value (NPV)) was assessed in each of the three fractions: first streams (F1), machine milk (F2) and stripping milk (F3). Milking fraction, mammary gland health status and lactation number had a significant effect on EC and SCC. In the case of EC, the milking fraction caused a more pronounced effect than health status of the glands or number of lactation (F = 19.95, 15.88 and 6.55, respectively; P &amp;lt; 0.5). In SCC, the gland health status caused the most pronounced effect followed by milking fraction and lactation number (F = 112.02, 6.89, and 5.28, respectively; P &amp;lt; 0.05). Changes in the milk composition, especially fat and lactose contents, explained the EC variation to a great extent. For the same EC threshold, specificity and sensitivity varied slightly depending on the milking fraction. NPV above 80% was obtained in the three milking fractions and at all EC thresholds tested, but PPV was only higher than 20% as of the threshold of 4.5, 4.4, and 4.2 mS/cm in F1, F2 and F3, respectively. From the results obtained, we concluded that the algorithm design for mastitis detection in sheep should include those factors affecting the composition and which therefore cause variations in EC, such as milking fraction, individual differences, lactation stage or lactation number.

Machine milking parameters for an efficient and healthy milking in dairy camels (Camelus dromedarius)

The effect of vacuum level and pulsation rate on machine milking efficiency in lactating dromedary camels were studied in 2 separate experiments. In the first experiment, a total of 14 multiparous camels in early (n=7) and late (n=7) lactation were used to study the effects of vacuum level (45 and 50 kPa) and pulsation rate (52 and 60 pulsations/min) on milk fractionation and flows traits. At the morning milking, volumes of machine milk (MM), machine stripping milk (MSM) and residual milk (RM) were recorded at two different days. For the second experiment, another 10 multiparous dromedary camels at mid stage of lactation were used to evaluate teat condition and udder health during 10 weeks. Milk samples were collected weekly at each milking and analysed for major milk constitutes and udder health. The 50 kPa vacuum level and 60 pulsations/min decreased (P<0.05) the MSM (from 15.2 to 5.9%) and RM (from 44.1 to 29.8%) compared to 45 kPa and 52 pulsation rate. Moreover, milking camels at high vacuum level resulted in significantly more milk in a shorter time with higher milk flows rate at early stage of lactation. No subclinical mastitis was detected in any of udders quarters as indicated by the CMT (<1), SCC (387×103±86 cells/mL) and bacteriology (coliform=0 and total flora=32097±396 ufc/mL) test. There were no differences in teat diameters, texture and color before and after milking. In conclusion, dromedary camels are readily to milk efficiently at 50 kPa and 60 pulsations/min without affecting negatively teat condition or udder health.

Effects of pulsation type (alternate and simultaneous) on mechanical milking of dairy goats (I): A study in Alpine goats varying the system vacuum level

The aim of this study was to assess the effect of alternate and simultaneous pulsation on milking performance (milk yield, machine stripping milk, milking duration, and average milk flow rate) of Alpine goats milked at two different system vacuum levels (38 and 42kPa). To this end, a field study was carried out in a commercial farm of Northern Italy. A pre-experimental period was carried out and 164 goats with a similar parturition date were selected and distributed into two similar subplots of 82 goats according to their values of milk yield and milking duration. The experiment lasted 24 d and was laid out as a split-plot design. Each treatment lasted 3days. Once every combination (2 pulsation types×2 vacuum levels) was tested (Experiment 1), the same experimental design was repeated in reverse order (cross-over design) to control the effect of lactation progress on the results (Experiment 2). Milk traits regarding milking performance (milk yield, machine stripping milk, milking duration, and average milk flow rate) and variables related to vacuum level in the milking cluster (vacuum in the short milk tube and vacuum fluctuation in the short milk tube) were recorded during morning and afternoon milkings. Results showed that the use of alternate pulsation reduced the vacuum fluctuations and increased the average vacuum in the short milk tube. Moreover, when a higher system vacuum level (42kPa) was set, the use of alternate pulsation reduced the milking duration. We concluded that the use of alternate pulsation offers some advantages compared to simultaneous pulsation in high milk flow conditions.

Effects of manual udder stimulation on milk partitioning and flow traits during the machine milking in dairy camels (Camelus dromedarius)

A total of 9 multiparous dromedary camels in late stage of lactation (287±8 DIM; 3.8±0.8 kg/d) were used to study the effect of manual udder stimulation on machine milking efficiency of dairy camels under intensive management condition. Experimental design consisted of 3x3 Latin square with 9 animals allocated randomly and equally to 3 treatment (T1=60 s, T2=90 s and T3=120 s). All camels were machine milked twice daily. Milk yield and milk flow parameters were recorded by Lactocorder® milk meters. Udder health was evaluated by California mastitis test (CMT) and somatic cell counts (SCC). Cisternal milk was determined 14 h after milking using Atosiban®. Volumes of machine milk (MM), machine stripping milk (MSM) and residual milk (RM) were recorded in duplicate. No subclinical mastitis was detected during the experimental period as indicated by the CMT ( 25%). The increase of udder stimulation from T1 to T3 decreased (p<0.05) the lag time (LT) (3.83 to 2.24 sec) in camels of G1 and the MSM (26.6 to 14.8%) as well as RM (46.1 to 31.4%) in camels of G2. Bimodal curves tended (P=0.08) to decrease from 43.6% to 28.1% when duration of udder stimulation increased from T1 to T3 in camels of G2. In conclusion, increase duration of manual udder stimulation to 90–120 s ameliorate the machine milking efficiency in harder milked camels at late stage of lactation. (Resume d'auteur)

Ergonomics in Modern Dairy Practice: A Review of Current Issues and Research Needs

ABSTRACT Dairy farming is an ancient occupation. Traditionally, cows have been manually milked while tethered in stalls or stanchions. In the latter half of the 20th century as machine milking emerged, the parlor milking system has become more popular, especially among larger dairy farms. The transition from manual milking to automatic milking systems as well as the transition from stanchion to parlor milking systems involved a dramatic change in milking tasks. These transitions have resulted in changing patterns of occupational exposure to risk factors for work-related musculoskeletal disorders among dairy workers. However, aspects of the milking task such as sanitization of teats, stripping milk from teats, and attachment and detachment of milking equipment have remained relatively the same. Work-related musculoskeletal symptoms have been reported in the low back, shoulders, hands/wrists, and knees. Research that has measured exposures to risk factors for work-related musculoskeletal disorders among dairy farm workers has been limited, especially when using ergonomic tools to directly measure exposure, such as electrogoniometry or electromyography. Self-reported exposure measures have been most commonly used. The interventions that have been tested to reduce exposure to risk factors for work-related musculoskeletal disorders include assisted lift-hold devices, use of lighter-weight equipment, adjustable flooring, and use of rubber mats. However, research evaluating potential solutions to reduce dairy farm worker exposure to risk factors for musculoskeletal disorders is scarce. Future research efforts should further characterize hazards while simultaneously testing viable solutions that fit within the business model of the dairy farm industry.

Comparison between two milk distribution structures in dairy goats milked at different milking frequencies

Twenty-four dairy goats of 3 breeds (Majorera, Tinerfeña, and Palmera) in mid lactation (110±7d in milk) were milked unilaterally at 2 frequencies (once: X1 or twice daily: X2) for 6wk to evaluate milk yield and milk composition and to compare two milk distribution structures. On the sampling days, milk volumes of each udder halves were recorded and analyzed. Milk partitioning was divided into: cisternal (CM) and alveolar milk (AM); and into: machine milk (MM), machine stripping milk (MSM), and residual milk (RM). In Majorera and Tinerfeña breeds did not find significant differences in milk yield and milk composition due to milking frequency. In contrast, Palmera goats had an increase of 14% in milk yield when they were milked X2 compared with X1, but the protein content was significantly higher in the milk of X1 (3.92%) than X2 (3.72%). Furthermore, the absence of differences in protein daily yield between X1 and X2, suggested that cheese yield could not be maintained. Milking frequency did not affect CM and AM percentages in the studied breeds. Regarding breed factor, Majorera and Palmera had the highest and lowest CM percentages, respectively, both in X1 and X2. On the other hand, MM and MSM percentages did not differ due to milking frequency in Tinerfeña and Palmera breeds. However, Majorera goats had significant differences in MM (77.29 vs. 71.66%) and MSM (12.67 vs. 17.41%) for X1 and X2, respectively. A breed effect was observed on MM and MSM fractions: Majorera goats had higher MM percentages, while Tinerfeña and Palmera goats had higher MSM percentages. RM fraction was not affected by milking frequency or breed factors. Finally, no significant correlation coefficients were detected when comparing CM and AM with MM, MSM and RM fractions, which indicates that both milk partitioning structures did not seem to be comparable between them, at least in goat udders that have a more horizontal teat insertion.

Variation in milk cortisol during lactation in Murciano-Granadina goats

Fifty-seven goats were included in an experiment designed to study the effect of lactation stage, parity number, and mammary gland health status on milk cortisol concentration as a method to assess the welfare of Murciano-Granadina goats. The relationships of milk cortisol concentration with different production parameters (milk yield, milk composition, and mechanical milking ability: milk fractioning during milking and milking time) were also studied. The experiment lasted 8mo and monthly samplings were carried out to determine total milk yield (MY), fractioning during milking (machine milk, MM; machine stripping milk, MSM), and milking time (MT), and a sample was taken from the total milk yield to determine milk cortisol concentration, somatic cell count, and milk composition (fat, protein, and lactose). To determine the infection status of the gland, an aseptic sample was taken for bacteriological analysis before each monthly sampling. Third-parity goats presented higher concentrations of milk cortisol than those of 1, 2, or ≥4 parities. Intramammary infection had no effect on milk cortisol concentration, and somatic cell count did not correlate with cortisol concentration. Cortisol presented a significant correlation with MY and MM, but showed no significant correlation with MSM, MT, or milk composition parameters. Variations in milk cortisol concentration in goats may be associated with different physiological factors in the animal (e.g., milk production level, lactation stage, and parity number) and therefore need not always indicate stress for the animal.

Analysis of the electrical conductivity in milking fractions as a mean for detecting and characterizing mastitis in goats

The aim of the work was to study the effect of milking fraction on electrical conductivity of milk (EC) to improve its use in dairy goat mastitis detection using automatic EC measurements during milking. The experiment was carried out on a group of 84 Murciano-Granadina goats (28 primiparous and 56 multiparous). Goats were in the fourth month of lactation. A linear mixed model was used to analyse the relationship between EC or somatic cell count (SCC) of gland milk and parity, mammary gland health status, analysed fraction (first 100mL=F-1; machine milk=F-2; and stripping milk=F-3) and their first order interactions. Additionally, the mastitis detection characteristics (sensitivity, specificity, positive predictive value and negative predictive value) of SCC and EC were studied at different thresholds.All factors considered were significant for EC and SCC. EC decreased significantly as milking progressed (from F-1 to F-3) in both healthy and infected glands. EC was not significantly different between healthy and infected glands in F-1 and F-2 fractions, but EC of healthy glands (5.01mS/cm) was significantly lower than in infected glands (5.03mS/cm) at F-3.Mastitis detection characteristics of EC did not differ amongst studied fractions. The small significant difference of EC between healthy and infected glands obtained in F-3 fraction did not yield better sensitivity results compared to F-1 and F-2. The best EC mastitis detection characteristics were obtained at 5.20mS/cm threshold (sensitivity of 70% and specificity of 50%). The best SCC mastitis detection characteristics were obtained at 300,000cells/mL threshold and F-3 fraction (sensitivity of 85% and specificity of 65%).It was concluded that mastitis detection characteristics of EC were similar in the three milking fractions analysed, being slightly better for SCC in F-3 fraction. As shown in previous studies, there are no factors other than the mammary gland health status that affect milk EC and should be considered in the algorithms for mastitis detection to improve the results.

Draft Genome Sequence of Enterococcus mundtii CRL1656

We report the draft genome sequence of Enterococcus mundtii CRL1656, which was isolated from the stripping milk of a clinically healthy adult Holstein dairy cow from a dairy farm of the northwestern region of Tucumán (Argentina). The 3.10-Mb genome sequence consists of 450 large contigs and contains 2,741 predicted protein-coding genes.

Effect of different hand-milking techniques on milk production and teat treatment in Zebu dairy cattle

The aim of the study was to test three different hand-milking techniques ("pull down", "thumb in", and "full hand grip") and their effects on milk production and teat treatment. This is important since milk production in many tropical areas still rely on hand-milking. The study was carried out at a peri-urban farm in the Bobo-Dioulasso area in Burkina Faso. Twelve indigenous Zebu cows in early lactation were used in the study. The sequences of the treatments (hand-milking techniques) and the milkers were balanced for carry-over effects between successive periods and days, respectively. The sequences were constructed by using special Latin squares. Yield and composition of saleable milk was not affected by milking technique but there were differences between the milkers in milk yield. There was also a significant interaction for saleable milk yield between milker and milking technique. Hemoglobin in milk was measured as an indicator of teat damage. The hemoglobin content was numerically higher in post-milking strip milk samples than in saleable milk. It was concluded that the amount of milk removed depends mainly on the milker and how well the milking technique works for the individual milker. No effect of milking technique was observed on teat treatment.

Day-to-day variation in yield, composition and somatic cell count of saleable milk in hand-milked zebu dairy cattle.

The aim of the study was to determine the relative day-to-day variation in yield and composition of zebu cows. Ten multiparous zebu cows in day 41 ± 1.6 of lactation were used in the study. After a 14 day adaptation period, milk production was recorded daily for four consecutive weeks. Cows had access to natural pasture for 6.5 h per day and were also supplemented with hay, cottonseed cake and molasses. The cows were hand-milked and calves were used to stimulate milk ejection before and during milking. Average yield of saleable milk was 2.08 ± 0.23 l/day with a relative day-to-day variation of 18 -21%. The variation of saleable milk was 23 - 25% for fat, 12 - 14% for protein, 6% for lactose and 8% for somatic cell count. The variation in fat content was higher in strip milk (19 - 46%) than in saleable milk. The results indicated a larger variation in composition of milk from hand-milked Bos indicus Zebu than from machine‑milked Bos taurus cows. The most likely reasons for the difference in variation are the suckling by the calf and that hand-milking entails larger variation in the degree of emptying machine-milking does. Key words: Zebu, cow, milk, day-to-day variation, milk composition.

Screening of surface properties and antagonistic substances production by lactic acid bacteria isolated from the mammary gland of healthy and mastitic cows

Bovine mastitis (BM) is a costly disease in dairy cattle production. The prevention and treatment of mastitis is performed by applying antimicrobial products that negatively affect milk quality. In the last years, the use of probiotic microorganisms to prevent infections in humans and animals has being aggressively studied. Samples from teat canal and milk (foremilk and stripping) were taken from healthy and mastitic mammary quarters. A screening of the surface properties and antagonistic substances production of lactic acid bacteria (LAB) isolated from the mammary gland was performed to select potential probiotic strains to prevent mastitis. Somatic cell count, physico-chemical and microbiological studies were carried out. Pre-selected microorganisms were genetically identified. Compared with stripping milk, foremilk showed lower levels of fat and higher levels of pH, density, microorganism numbers, lower percentage of strains with mean and high hydrophobicity and mean autoaggregation and higher number of strains able to produce hydrogen peroxide and bacteriocins. The other parameters analyzed were not statistically significant. One hundred and two LAB strains were isolated. Most of them had low degrees of hydrophobicity and autoaggregation. No correlation between these properties was found. Antagonistic metabolites were mainly produced by strains isolated from healthy quarters. Most of the pre-selected strains were identified as Streptococcus bovis and Weissella paramesenteroides. Three bacteriocin-producers were found and their products partially characterized. The results of this work are the basis for the further design of a specie-specific probiotic product able to prevent BM.

Effects of the frequency of milking and lactation stage on milk fractions and milk composition in Tinerfeña dairy goats

Machine milk (MM), machine stripping milk (MSM), residual milk (RM), and milk protein and fat content were recorded during the second lactation in 49 Tinerfeña goats milked once (X1) and twice (X2) a day. MM, MSM and RM percentages were 67.7% and 62.4%, 20.2% and 30.2%, 12.1% and 7.4% in X1 and X2, respectively. Milking frequency statistically affected MSM, RM and fat content, but increasing milking frequency from once to twice a day did not improve milkability nor did it significantly affect milk yields.

Order of sheep entry into the milking parlour and its relationship with their milkability

Sixty Manchega ewes were used to evaluate whether recently weaned dairy sheep organise themselves into a well-defined sequence to enter into the milking parlour and to study the effects on their milkability during an 11-week milking period after a 5-week suckling+milking period. A two-platform milking parlour was used, with 12 stalls on each platform and a milking routine including machine stripping and hand stripping. Conclusive evidence of the existence of a milking order was established. Animals which were in the last group to enter the milking parlour presented milk ejection less (P<0.01) frequently, a lower (P<0.001) percentage of machine milking fractions and a higher (P<0.001) percentage of stripping milk fractions. However, somatic cell count was not significantly correlated to any of the tested variables. Thus, the order of entry into the milking parlour after weaning is a good indicator of sheep milkability throughout lactation.