Marian Wiercioch, Adam Luberański, Krzysztof Lejman, Małgorzata Fugol and Hubert Prask
A liner is the only part of the milking unit which has a direct contact with a cow’s teat. It ensures a correct circulation of body liquids in a teat with its suitable massage and creates conditions for a teat to open and milk to flow out and maintains a milking cup on a teat. The result of the last task is generation of a suction force that sucks a teat into a liner. During milking, when a cup is placed on a teat, counter forces are generated that try to remove a liner from a teat and forces that cause that a teat moves up to a liner producing a phenomenon of “a climbing cup”. Forces that tend to separate a teat from a liner depend on the mass of a milking cup set and the value of the friction force. A counter force that tends to suck a teat into a liner is proportional to the level of negative pressure in a liner and the surface of cross-section of a teat that is subjected to negative pressure. We should also assume that also the structure of a liner will influence this force. The paper presents results of the laboratory tests on the impact of the shape of the cross-section of a rubber core and construction solutions of liners on the vacuum force of a liner when a teat is sucked into a teat chamber. Eight liners, popular in milking machines used in our country were used in the tests. Various penetrations of a teat (50, 62, 75 and 100 mm), working pressure (25-55 kPa) and a working stage of the milking cup were additional variables. In order to determine whether and what is the degree of the impact of variability sources on shaping the suction forces of a liner, a static processing of results was carried out using a multi-variance analysis. It was proved that at the significance level of α=0.05, the source of variability assumed in the experiment in the form of the liner shape, negative pressure and penetration affected the analysed sizes, i.e. Average values of suction forces in the suction phase (Fws) and massage phase (Fwm). The investigation of the impact of the rubber core part on the determined values of the suction force in the function of variable negative pressure proved that at teat penetration of 50 and 62 mm (the most popular lengths of teats in milked cows), the lowest suction force was observed in case of a liner with a triangular cross-section, slightly bigger with a square cross-section and the highest suction force is generated by round and oval liners.
Adam Luberański, Marian Wiercioch, Józef Szlachta, Aleksander Krzyś and Danuta Skalska
Improvement of mechanical milking in the aspect of cow's udder health and maintaining correct milking parameters is possible through e.g. constant improvement of the structure of clusters. A cluster with a specific claw with crossing milk connection pipes Flo-Star Max with liners with a round profile of the barrel of DK1X. The objective of the paper was to analyse usefulness of this type of the sitructure of the machine for mechanical milking of cows. Measurements of simulated milking were carried out in a laboratory to the upper milking pipeline at variable mass intensity of liquid flow within 0-8 kg·min−1, for four penetrations of artificial teats of 100, 75, 62, 50 mm at the systemic negative pressure values within 50 to 44 kPa, simultaneous and alternating pulsation and during real milking of cows in a cowshed. Using a multivariate analysis of variance, the impact of independent variables of an experiment on the values of average vacuum of suction, vacuum fluctuations in cycle, average drop of vacuum in a cycle were proved. Analysis of the machine operation in a milking parallel parlour in real mechanical milking conditions and difficulties in placing a machine on the cow's udder as well as violent milk flow were reported and the milk flow of 3.5 kg·min−1 was exceeded with its characteristic balancing in the rhythm of a pulsator.
Francesca Dai, Giulia Segati, Emanuela Dalla Costa, Faith Burden, Andrew Judge and Michela Minero
Limited information is available about the actual management characteristics of dairy donkeys in Southern Europe. The aim of the present study is to describe animal management of dairy donkey farms in Italy. Twelve farmers were asked to answer a questionnaire on the management of their animals and their farms distributed over the Italian territory. Six farms grouped their animals in paddocks according to the production characteristics (e.g. lactating, dry, stallions); three farms housed the stallions in single boxes. Most of the visited farms were family run and the number of animals cared for by a single person varied from five to 103 animals. All the farms but one performed mechanical milking with a modified goat milkmaid. Vaccinations were regularly performed only on two farms. All the foals received colostrum and suckled from their own mothers. Foals were nursed by their mother until 6-12 months old. During the separation period before milking, foals were usually (83%) housed in paddocks near their mothers with the possibility of visual and/or tactile contact, however such separations could be for up to 12 hours (17%). Even though the assessed sample was small, considerable differences were seen between farms, likely due to lack of uniform information available for the farmers. The adoption of scientific based procedures is suggested in order to improve both animal welfare and milk quality.
This article critically explores Foucauldian approaches to the human-animal-technology nexus central to modern industrialised agriculture, in particular those which draw upon Foucault’s conception of power as productive to posit the reconstitution of animal subjectivities in relation to changing agricultural technologies. This is situated in the context of key recent literature addressing animals and biopolitics, and worked through a historical case study of an emergent dairy technology. On this basis it is argued that such approaches contain important insights but also involve risks for the analyses of human-animal-technology relations, especially the risk of subsuming what is irreducible in animal subjectivity and agency under the shaping power of technologies conceived as disciplinary or biopolitical apparatuses. It is argued that this can be avoided by bringing biopolitical analysis into dialogue with currents from actor-network theory in order to trace the formation of biopolitical collectives as heterogeneous assemblages. Drawing upon documentary archive sources, the article explores this by working these different framings of biopolitics through a historical case study of the development of the first mechanical milking machines for use on dairy farms.
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Mijic P, Knezevic I, Domacinovic M, Ivankovic A, Ivkic Z (2005): Relationship between various phases of milk flow at mechanicalmilking system and the somatic cell count in cows‵ milk. J Anim Feed Sci 14: 483-490.
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Tina Bobić, Pero Mijić, Vesna Gantner, Gjoko Bunevski and Maja Gregić
mastitis prevalence in Gir cows. Pesq Agropec Bras. 45 (12): 1507-1512. https://doi.org/10.1590/S0100-204X2010001200023
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