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Rupert M. Bruckmaier - One of the best experts on this subject based on the ideXlab platform.
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Investigations on milk flow and milk yield from teats with milk flow disorders
Journal of dairy science, 2002Co-Authors: Julia Querengässer, Rupert M. Bruckmaier, T. Geishauser, Klaus Querengässer, K. FehlingsAbstract:The objective of this study was to investigate peak milk flow, average milk flow, and milk yield in teats with milk flow disorders. A total of 100 hard Milking teats were studied in 97 cows. Teats with milk flow disorders were examined endoscopically. Quarter milk flow and quarter milk yield were examined with four Lactocorders attached to a quarter Milking Machine. Peak milk flow, average milk flow, and milk yield were measured in all teats of the udder before treatment of the affected teat, as well as 1 and 6 mo later. Teats with milk flow disorders were compared to all other teats of the same udder. Before treatment, peak milk flow from affected teats was 20%, average milk flow 14%, and milk yield 53% of the control teats, adjusted for other significant explanatory variables. Milk flow and milk yield increased after surgical treatment of the affected teats. Six months after treatment peak milk flow was 79%, average milk flow 76%, milk yield was 71% compared with control teats. We conclude from these findings that teat endoscopy and measuring quarter milk flow and milk yield with Lactocorders are useful tools for examining teats with milk flow disorders.
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Milk ejection during Machine Milking in dairy cows
Livestock Production Science, 2001Co-Authors: Rupert M. BruckmaierAbstract:Abstract Only a small percentage of cisternal milk, usually less than 20 percent is immediately available for milk removal in dairy cows. Most of the milk, the alveolar milk, is stored in alveoli and small milk ducts and is fixed by capillary forces. Removal of the alveolar fraction requires active expulsion of milk into the cisternal cavities by the milk ejection reflex. Tactile teat stimulation causes release of oxytocin (OT) from the posterior pituitary into circulation. Myoepithelial cells, surrounding the alveoli, contract in response to elevated OT concentrations and the alveolar milk is shifted through the milk duct system into the cistern to be removed by the Milking Machine. The delay in milk ejection after the start of teat stimulation changes during the course of lactation and depends of the interval from previous Milking. Milk ejection is not completed with the occurrence of alveolar milk in the cistern during early Milking. The process of shifting milk continues until the end of milk removal, and continuously elevated concentrations of OT throughout the entire Milking are essential to maintain milk ejection until the udder is emptied. In cows with very high milk flow rates during early Milking, milk ejection may be a limiting factor for milk flow towards the end of Milking.
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oxytocin release and milk removal in ruminants
Journal of Dairy Science, 1998Co-Authors: Rupert M. Bruckmaier, J W BlumAbstract:Abstract Before Milking, less than 20% of the milk yielded by dairy cows is stored within the cistern, where it is immediately available for removal. Most of the milk is available for the Milking Machine only after milk ejection, which occurs in response to tactile teat stimulation and oxytocin release. For complete milk removal, milk ejection is necessary throughout the entire Milking process. The continuation of stimulatory effect of the Milking Machine until the end of Milking is, therefore, essential. PreMilking teat stimulation causes induction of alveolar milk ejection before the start of Milking. Thus, bimodal milk flow curves (i.e., interruption of milk flow after removal of the cisternal milk) are avoided. Continual ejection of milk is dependent on the presence of elevated oxytocin concentrations during the entire Milking. Any interruption of the milk ejection process can disturb milk removal. Disruption of milk removal can be caused by peripheral inhibition of oxytocin effects on the mammary gland or by inhibition of oxytocin release by the central nervous system. Peripheral inhibition is induced by elevated concentrations of catecholamines through stimulation of α -adrenergic receptors in the mammary gland, likely via changes in ductal resistance. Inhibition of oxytocin release by the central nervous system has been observed in primiparous cows immediately after parturition, during peak estrus, and during Milking in unfamiliar surroundings; concentrations of β -endorphin and cortisol are elevated in this situation. However, the role of endogenous opioid peptides in the inhibition of oxytocin release in cows remains unclear. In conclusion, during Machine-Milking, the physiological requirements of the cows need to be considered, and, most importantly, stressors must be minimized.
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Interruption of Machine Milking in Dairy Cows: Effects on Intramammary Pressure and Milking Characteristics
Journal of Dairy Research, 1995Co-Authors: Hans Ulrich Pfeilstickee, Rupert M. Bruckmaier, Jürg W. BlumAbstract:Experiments were designed to test the hypothesis that milk ejection rate decreases during Milking, thereby causing insufficient refill of the cistern and decreasing milk flow rate towards the end of Milking. In a first series of experiments Machine Milking of the left front quarters of 11 cows was interrupted for 2 min after removal of 25, 50 or 75% of expected total milk yield, while Milking was continued in the other three quarters. Milk flow was recorded during Machine-on times. Intramammary pressure (IMP) was recorded during preMilking teat stimulation and during interruption of Milking. IMP during interruption of Milking decreased with decreasing amounts of milk remaining in the udder. The IMP did not change during these interruptions when they occurred after 25 and 50% of expected total milk yield was removed. Thus, the ejection rate could keep up with the milk flow or removal rate. However, IMP increased during interruption of Milking following removal of 75% of total yield, although significantly so only in cows with a high milk flow rate. Obviously, more milk was removed than was transported to the cisternal cavity. It is likely that a reduced ejection rate caused the decreased milk flow rate. In a second series of experiments the pulsation ratio of the Milking Machine was changed from the usual 70:30 to 50:50 with the aim of reducing the milk flow rate and thus adapting to the ejection rate at the end of Milking. The changed pulsation ratio caused a reduced peak flow rate and a prolonged high milk flow period, whereas the main flow rate did not change significantly.
Ruth N. Zadoks - One of the best experts on this subject based on the ideXlab platform.
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streptococcus agalactiae in the environment of bovine dairy herds rewriting the textbooks
Veterinary Microbiology, 2016Co-Authors: Hannah J Jorgensen, Ruth N. Zadoks, A B Nordstoga, S Sviland, L Solverod, Bjorg Kvitle, T MorkAbstract:Many free-stall bovine dairy herds in Norway fail to eradicate Streptococcus agalactiae despite long-term control measures. In a longitudinal study of 4 free-stall herds with automatic Milking systems (AMS), milk and extramammary sites were sampled 4 times with 1-2 month intervals. Composite milk, rectal- and vaginal swabs were collected from dairy cows; rectal swabs from heifers and young stock; rectal- and tonsillar swabs from calves; and environmental swabs from the AMS, the floors, cow beds, watering and feeding equipment. A cross sectional study of 37 herds was also conducted, with 1 visit for environmental sampling. Fifteen of the herds were known to be infected with S. agalactiae while the remaining 22 had not had evidence of S. agalactiae mastitis in the preceding 2 years. All samples were cultured for S. agalactiae, and selected isolates (n=54) from positive herds were genotyped by Multi Locus Sequence Typing (MLST). Results show that the bovine gastrointestinal tract and the dairy cow environment are reservoirs of S. agalactiae, and point to the existence of 2 transmission cycles; a contagious transmission cycle via the Milking Machine and an oro-fecal transmission cycle, with drinking water as the most likely vehicle for transmission. Ten sequence types were identified, and results suggest that strains differ in their ability to survive in the environment and transmit within dairy herds. Measures to eradicate S. agalactiae from bovine dairy herds should take into account the extra-mammary reservoirs and the potential for environmental transmission of this supposedly exclusively contagious pathogen.
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Multilocus Sequence Typing of Intercontinental Bovine Staphylococcus aureus Isolates
Journal of Clinical Microbiology, 2005Co-Authors: Edward M. Smith, Ynte H. Schukken, Ruth N. Zadoks, Laura E. Green, Graham F. Medley, H. E. Bird, Lawrence K. Fox, J. V. Kruze, Andrew J. Bradley, Christopher G. DowsonAbstract:A total of 258 bovine-associated Staphylococcus aureus isolates from the United States, Chile, and the United Kingdom, plus the reference isolate S. aureus Newbould 305 (NCIMB 702892), were analyzed by multilocus sequence typing (MLST). A collection of previously characterized United Kingdom isolates were also included in the analysis. The results demonstrated that MLST is suitable for the differentiation of bovine S. aureus isolates from various sites (milk, teat skin, Milking Machine unit liners, hands, and bedding) and countries. The theory of the host specificity of S. aureus is supported by the detection of a previously undescribed clonal complex that comprised 87.4% of the isolates studied, with representatives from all geographic locations investigated. This suggests that a single clonal group has achieved a widespread distribution and is responsible for the majority of infections. Some sequence types (STs; ST25, ST115, ST124, and ST126) demonstrated site specificity, as they were significantly (P < 0.05) associated with milk or teat skin.
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clinical epidemiological and molecular characteristics of streptococcus uberis infections in dairy herds
Epidemiology and Infection, 2003Co-Authors: Ruth N. Zadoks, O C Sampimon, B E Gillespie, Herman W. Barkema, S.p. Oliver, Ynte H. SchukkenAbstract:SUMMARY A longitudinal observational study (18 months) was carried out in two Dutch dairy herds to explore clinical, epidemiological and molecular characteristics of Streptococcus uberis mastitis. Infections (n=84) were detected in 70 quarters of 46 cows. Bacterial isolates were characterized at strain level by random amplified polymorphic DNA (RAPD) fingerprinting. Persistent infections were usually attributable to one strain, while recurrent infections could be caused by different strains. When multiple quarters of a cow were infected, infections were mostly caused by one strain. In each herd, multiple strains were identified yet one strain predominated. The majority of all infections were subclinical, and infections attributed to predominant strains were more chronic than infections attributed to other strains. Epidemiological and molecular data suggest infection from environmental sources with a variety of S. uberis strains as well as within-cow and between-cow transmission of a limited number of S. uberis strains, with possible transfer of bacteria via the Milking Machine.
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Comparison of Staphylococcus aureus Isolates from Bovine and Human Skin, Milking Equipment, and Bovine Milk by Phage Typing, Pulsed-Field Gel Electrophoresis, and Binary Typing
Journal of clinical microbiology, 2002Co-Authors: Ruth N. Zadoks, Herman W. Barkema, Ynte H. Schukken, Lawrence K. Fox, W. Van Leeuwen, D. Kreft, A. Van BelkumAbstract:Staphylococcus aureus isolates (n = 225) from bovine teat skin, human skin, Milking equipment, and bovine milk were fingerprinted by pulsed-field gel electrophoresis (PFGE). Strains were compared to assess the role of skin and Milking equipment as sources of S. aureus mastitis. PFGE of SmaI-digested genomic DNA identified 24 main types and 17 subtypes among isolates from 43 herds and discriminated between isolates from bovine teat skin and milk. Earlier, phage typing (L. K. Fox, M. Gershmann, D. D. Hancock, and C. T. Hutton, Cornell Vet. 81:183-193, 1991) had failed to discriminate between isolates from skin and milk. Skin isolates from humans belonged to the same pulsotypes as skin isolates from cows. Milking equipment harbored strains from skin as well as strains from milk. We conclude that S. aureus strains from skin and from milk can both be transmitted via the Milking Machine, but that skin strains are not an important source of intramammary S. aureus infections in dairy cows. A subset of 142 isolates was characterized by binary typing with DNA probes developed for typing of human S. aureus. Typeability and overall concordance with epidemiological data were lower for binary typing than for PFGE while discriminatory powers were similar. Within several PFGE types, binary typing discriminated between main types and subtypes and between isolates from different herds or sources. Thus, binary typing is not suitable as replacement for PFGE but may be useful in combination with PFGE to refine strain differentiation.
F. San Primitivo - One of the best experts on this subject based on the ideXlab platform.
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Factors of variation influencing bulk tank somatic cell count in dairy sheep.
Journal of Dairy Science, 2005Co-Authors: Carlos Gonzalo, Miriam Blanco, E. Beneitez, J A Carriedo, M T Juarez, L F De La Fuente, F. San PrimitivoAbstract:Between January and December 2002, a total of 21,685 records for bulk tank milk somatic cell count (BTSCC) were obtained from 309 dairy ewe herds belonging to the Sheep Improvement Consortium in Castilla-Leon, Spain. Based on the first statistical model, ANOVA detected significant effects of herd, breed, month within herd, dry therapy, type of Milking, contagious agalactia, and installations within Machine Milking on logBTSCC. A second statistical model was used on herds with Machine Milking to study the effect of the vacuum level and pulsation rate on BTSCC. Herd and month within herd were important variation factors as they explained 48.4 and 16.1% of the variance in BTSCC. Variability in logBTSCC among breeds ranged from 5.84 (Castellana) to 6.09 (Awassi and Spanish Assaf). Implementing dry-ewe therapy (5.91) significantly reduced logBTSCC compared with when it was not implemented (6.10). Hand Milking elicited greater logBTSCC (6.07) than Machine Milking (5.94). Machine Milking of ewes in Milking parlors (logBTSCC: 5.88 to 5.94) was associated with better udder health than was the use of bucket-Milking Machines (6.04). Reduced vacuum levels and elevated pulsation rate during Machine Milking optimized BTSCC. In all cases, clinical outbreaks of contagious agalactia increased BTSCC. As a result, dry therapy was proposed as the main tool to reduce BTSCC. Optimization of Milking-Machine standards and parlor systems also improved udder health in dairy sheep.
Ynte H. Schukken - One of the best experts on this subject based on the ideXlab platform.
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Multilocus Sequence Typing of Intercontinental Bovine Staphylococcus aureus Isolates
Journal of Clinical Microbiology, 2005Co-Authors: Edward M. Smith, Ynte H. Schukken, Ruth N. Zadoks, Laura E. Green, Graham F. Medley, H. E. Bird, Lawrence K. Fox, J. V. Kruze, Andrew J. Bradley, Christopher G. DowsonAbstract:A total of 258 bovine-associated Staphylococcus aureus isolates from the United States, Chile, and the United Kingdom, plus the reference isolate S. aureus Newbould 305 (NCIMB 702892), were analyzed by multilocus sequence typing (MLST). A collection of previously characterized United Kingdom isolates were also included in the analysis. The results demonstrated that MLST is suitable for the differentiation of bovine S. aureus isolates from various sites (milk, teat skin, Milking Machine unit liners, hands, and bedding) and countries. The theory of the host specificity of S. aureus is supported by the detection of a previously undescribed clonal complex that comprised 87.4% of the isolates studied, with representatives from all geographic locations investigated. This suggests that a single clonal group has achieved a widespread distribution and is responsible for the majority of infections. Some sequence types (STs; ST25, ST115, ST124, and ST126) demonstrated site specificity, as they were significantly (P < 0.05) associated with milk or teat skin.
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clinical epidemiological and molecular characteristics of streptococcus uberis infections in dairy herds
Epidemiology and Infection, 2003Co-Authors: Ruth N. Zadoks, O C Sampimon, B E Gillespie, Herman W. Barkema, S.p. Oliver, Ynte H. SchukkenAbstract:SUMMARY A longitudinal observational study (18 months) was carried out in two Dutch dairy herds to explore clinical, epidemiological and molecular characteristics of Streptococcus uberis mastitis. Infections (n=84) were detected in 70 quarters of 46 cows. Bacterial isolates were characterized at strain level by random amplified polymorphic DNA (RAPD) fingerprinting. Persistent infections were usually attributable to one strain, while recurrent infections could be caused by different strains. When multiple quarters of a cow were infected, infections were mostly caused by one strain. In each herd, multiple strains were identified yet one strain predominated. The majority of all infections were subclinical, and infections attributed to predominant strains were more chronic than infections attributed to other strains. Epidemiological and molecular data suggest infection from environmental sources with a variety of S. uberis strains as well as within-cow and between-cow transmission of a limited number of S. uberis strains, with possible transfer of bacteria via the Milking Machine.
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Comparison of Staphylococcus aureus Isolates from Bovine and Human Skin, Milking Equipment, and Bovine Milk by Phage Typing, Pulsed-Field Gel Electrophoresis, and Binary Typing
Journal of clinical microbiology, 2002Co-Authors: Ruth N. Zadoks, Herman W. Barkema, Ynte H. Schukken, Lawrence K. Fox, W. Van Leeuwen, D. Kreft, A. Van BelkumAbstract:Staphylococcus aureus isolates (n = 225) from bovine teat skin, human skin, Milking equipment, and bovine milk were fingerprinted by pulsed-field gel electrophoresis (PFGE). Strains were compared to assess the role of skin and Milking equipment as sources of S. aureus mastitis. PFGE of SmaI-digested genomic DNA identified 24 main types and 17 subtypes among isolates from 43 herds and discriminated between isolates from bovine teat skin and milk. Earlier, phage typing (L. K. Fox, M. Gershmann, D. D. Hancock, and C. T. Hutton, Cornell Vet. 81:183-193, 1991) had failed to discriminate between isolates from skin and milk. Skin isolates from humans belonged to the same pulsotypes as skin isolates from cows. Milking equipment harbored strains from skin as well as strains from milk. We conclude that S. aureus strains from skin and from milk can both be transmitted via the Milking Machine, but that skin strains are not an important source of intramammary S. aureus infections in dairy cows. A subset of 142 isolates was characterized by binary typing with DNA probes developed for typing of human S. aureus. Typeability and overall concordance with epidemiological data were lower for binary typing than for PFGE while discriminatory powers were similar. Within several PFGE types, binary typing discriminated between main types and subtypes and between isolates from different herds or sources. Thus, binary typing is not suitable as replacement for PFGE but may be useful in combination with PFGE to refine strain differentiation.
Laurence Shalloo - One of the best experts on this subject based on the ideXlab platform.
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investment appraisal of technology innovations on dairy farm electricity consumption
Journal of Dairy Science, 2015Co-Authors: J. Upton, Michael D Murphy, P Groot W G Koerkamp, P B M Berentsen, Imke J.m. De Boer, Laurence ShallooAbstract:Abstract The aim of this study was to conduct an investment appraisal for milk-cooling, water-heating, and milk-harvesting technologies on a range of farm sizes in 2 different electricity-pricing environments. This was achieved by using a model for electricity consumption on dairy farms. The model simulated the effect of 6 technology investment scenarios on the electricity consumption and electricity costs of the 3 largest electricity-consuming systems within the dairy farm (i.e., milk-cooling, water-heating, and Milking Machine systems). The technology investment scenarios were direct expansion milk-cooling, ice bank milk-cooling, milk precooling, solar water-heating, and variable speed drive vacuum pump-Milking systems. A dairy farm profitability calculator was combined with the electricity consumption model to assess the effect of each investment scenario on the total discounted net income over a 10-yr period subsequent to the investment taking place. Included in the calculation were the initial investments, which were depreciated to zero over the 10-yr period. The return on additional investment for 5 investment scenarios compared with a base scenario was computed as the investment appraisal metric. The results of this study showed that the highest return on investment figures were realized by using a direct expansion milk-cooling system with precooling of milk to 15°C with water before milk entry to the storage tank, heating water with an electrical water-heating system, and using standard vacuum pump control on the Milking system. Return on investment figures did not exceed the suggested hurdle rate of 10% for any of the ice bank scenarios, making the ice bank system reliant on a grant aid framework to reduce the initial capital investment and improve the return on investment. The solar water-heating and variable speed drive vacuum pump scenarios failed to produce positive return on investment figures on any of the 3 farm sizes considered on either the day and night tariff or the flat tariff, even when the technology costs were reduced by 40% in a sensitivity analysis of technology costs.
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assessing the impact of changes in the electricity price structure on dairy farm energy costs
Applied Energy, 2015Co-Authors: J. Upton, Michael D Murphy, P Groot W G Koerkamp, Laurence Shalloo, Imke J.m. De BoerAbstract:This study aims to provide information on the changes in electricity consumption and costs on dairy farms, through the simulation of various electricity tariffs that may exist in the future and how these tariffs interact with changes in farm management (i.e. shifting the Milking operation to an earlier or later time of the day). A previously developed model capable of simulating electricity consumption and costs on dairy farms (MECD) was used to simulate five different electricity tariffs (Flat, DayN milk cooling system, water heating system, Milking Machine system, lighting systems, water pump systems and the winter housing facilities. The effect of Milking start time was simulated to determine the effect on electricity consumption and costs at farm level. The earliest AM Milking start time and the latest PM Milking start time resulted in the lowest energy consumption. The difference between the lowest and highest electricity consumption within a farm was 7% for SF, 5% for MF and 5% for LF. This difference was accounted for by the variation in the milk cooling system coefficient of performance. The greatest scope to reduce total annual electricity costs by adjusting Milking start times was on TOU2 (39%, 34% and 33% of total annual electricity costs on the SF, MF and LF) and the least scope for reductions using this method was on the Flat tariff (7%, 5% and 7% of total annual electricity costs). The potential for reduction of annual electricity consumption and related costs per litre of milk produced by adjusting Milking times was higher for the LF than the SF or MF across all electricity tariffs. It is anticipated that these results and the use of the MECD will help support the decision-making process at farm level around increasing energy efficiency and electricity cost forecasts in future electricity pricing tariff structures.