No abstract

Many years of experience in the operation of milking machines show that milking rubber was and remains a short-lived and unreliable link in the technological process of machine milking. During operation, rubber quickly loses its strength and elastic properties, becomes stiff and less elastic, deforms, and changes its shape. The purpose of this study is to identify changes in the technical parameters of milking rubber under industrial conditions in order to establish their impact on the milking process. The obtained results could make it possible to rationally choose the milking rubber for teat cups, which would ensure an effective milking process. During this study’s initial stage, the physical and mechanical condition of milking rubber was experimentally established at steam disinfection and as a result of saturating the article with milk fats. The following stage implied detecting the effect of milking rubber tension in a teat cup on the speed of milking. It was established that milking rubber during operation is actively exposed to milk fat, which leads to the loss of its weight relative to its original value. On day 1,000 of work, the weight loss relative to the initial value (100 g), under the washing regime temperature of 85 °C, 50 °C, 35 °C, and 20 °C, was 1 g, 3.3 g, 5 g, and 4.2 g, respectively. The dependences have been derived for the swell mass of milking rubber M on the temperature of washing solutions T and the duration of operation t as a result of saturation with milk fats. The dependence of milk yield rate V on the tension force of milking rubber F in teat cups has been established. Thus, it was found that when the tension force of milking rubber changes from 25 to 60 N, the difference in the average intensity of milk yield is 0.13 kg/min (10.8 %). Regarding the amount of milk yield at the specified tension, the difference is 0.15 kg (2.5 %). At rubber tension from 60 to 25 N, the average milking time increases by 0.46 min (8.3 %). Thus, it was determined that a milking machine with milking rubber at different tension over a total milking time would unevenly milk different parts of the cow’s udder. The study reported here expands the idea about the technical and manufacturing characteristics of rubber articles, namely changes in them at steam disinfection and as a result of saturation with milk fats

Preparing cows for milking is one of the most important operations. Not only the speed of milk production but also the quality of milk depends on the level of the work performed. One of the most effective ways to mechanize the preparation of cows for milking implies the development of a special mechanical brush that cleans and stimulates the teat skin. As a result, there is no need to use additional foam detergents and napkins to cleanse and disinfect teats. A device has been designed for cleansing teats with two rotating brushes. Theoretical studies of the interaction of cleansing elements of the device for mechanical removal of pollutants from the udder teats in the course of milking operation were carried out. Assuming constancy of the modulus of elasticity, shape and roughness of teats, linear and angular velocities of brushes, nap stiffness, and homogeneity of physical and mechanical properties of contaminants on the teat, dependence of force Fe of the mechanical device on length l of the cleansing element and its speed ω was established. Under the condition that force Fe of the mechanical device is smaller than force Fp which causes pain but greater than the force retaining pollutants (adhesion), values of the main design and technological parameters of the developed device were determined: l=8 mm, ω=106 rpm. As a result of production tests, it was found that when using the developed device, the daily milk yield of the experimental group of cows exceeded that of the control group by an average of 1.1 times which has made it possible to obtain a supplement of 132.5 kg of milk. Along with this, there was a 0.19 % increase in milk fat content in the experimental group compared to the control group. The number of microorganisms decreased 2.2 times and the number of contaminant particles decreased 4.6 times

To implement effective cow milking, it is necessary to take into account the peculiarities of the milk flow process, the milking machine's adaptability to perform the given technological functions. The aim of research is to establish changes in the design and technological parameters and physical and mechanical properties of teat cup liner of milking machines during its testing and in production conditions. The results obtained will make it possible to make a rational choice of rubber, ensure an efficient milking process during its service life. It is found that the tensile strength of silicone teat cup liner at the beginning of operation was 1.6 times higher than that of a rubber compound, and after 6 months. operation – 1.7 times. With respect to the relative elongation, this difference was 1.4 times, and after operating time – 1.3 times. Studies have proven that rubber during operation changes its physical and mechanical properties: the length of the active part increased by 3.1 mm; wall thickness – 0.2 mm. It is found that the most intensively elastic properties of teat cup liner changed during the first 10–20 days. After 10 days, the closing vacuum increased by 16.6 % compared to the initial one, and after 20 days by 23.3 %, which amounted to 8.57 and 9.06 kPa, respectively. Up to 420 hours of operation, the clamping vacuum reached 11.3 kPa, which is 5.8 % lower than the requirements for toughening teat cup liner for rejection. In general, over the period of experiments, the average value of the vacuum of closing the opposite walls of teat cup liner increased from 7.35 to 12.43 kPa, which is 3.6 % higher than the norm (12 kPa). As a result of experimental studies, the regularity of the rubber tension force depending on the operating time in the form of a fourth degree polynomial is obtained. It is found that after 150 hours of operation, the tensile force of teat cup liner decreased by 21 %

The problem of treatment of subclinical mastitis often arises after calving, especially in cows of the first lactation. The paper presents the results of the therapeutic effect of Bacillus megaterium in subclinical mastitis in cows. The aim of the research. To determine the effect of Bacillus megaterium on the microflora of the gastrointestinal tract and colonies of microorganisms isolated from subclinical mastitis in cows. Materials and methods. The research was conducted in a dairy farm growing Holstein. Cows with subclinical mastitis of the experimental groups were given concentrated feed with the addition of Bacillus megaterium (1 × 109 CFU/g) at a dose of 15–35 g per animal. The control group of cows was given the usual diet for dairy cows. The experiment lasted 30 days. Results. The use of Bacillus megaterium (1 × 109 CFU/g) at a dose of 35 g per animal had a pronounced effect on the microflora of the gastrointestinal tract of cows. The amount of Lactobacillus sp. was 67 % higher and Bifidobacterium 58 % higher than the control. In addition, the level of opportunistic pathogens on Escherichia coli decreased by 45 %, Clostridium by 27 %, Enterobacteriaceae and Staphylococcus by 75 %, and Candida by 80 % compared to controls. The amount of microflora in milk decreased by 40.2 % and the number of somatic cells by 87.9 %. Conclusions. The therapeutic efficacy of Bacillus megaterium (1 × 109 CFU/g) at a dose of 35 g per animal for 30 days in subclinical mastitis has been proven. After treatment, the amount of microflora in cow's milk decreased by 40.2 % and the number of somatic cells by 87.9 %. A positive effect on the microflora of the gastrointestinal tract of cows, where the number of Lactobacillus sp. increased by 67 % and Bifidobacterium by 58 %. The level of opportunistic pathogenic microflora decreased by Escherichia coli – by 45 %, Clostridium – by 27 %, Enterobacteriaceae and Staphylococcus – by 75 %, Candida – by 80 %, compared to the control.