The aim of the present study was to determine the features and size of teat structures in cows using ultrasonography. The experiment was conducted with 12 clinically healthy Black-and-White cows, 3 years of age, with body weight of 350-450 kg. Ultrasonography was performed on 48 teats using ultrasound SonoScape A5v (SonoScape, China) with multifrequency linear transducer (5-12 MHz). The potential of the imaging technique to visualize teat structures as well as teat canal length and diameter, the diameter in the area of the Furstenberg’s rosette, teat wall thickness, teat cistern diameter in its middle part and teat cistern diameter in teat base was evaluated. Scans were conducted before milking, immediately after milking, and 1 and 2 hours after milking. The average teat canal length measured by ultrasound was 8.48±1.41 mm before milking, and until the 2nd post-milking hour its size became statistically significantly (p<0.001) lower (7.48±0.93 mm). Teat canal diameter showed a significant difference (p<0.01) only immediately after milking compared to the size before milking. The diameter of the middle part and the base of the teat cistern also tended to decrease considerably after milking (p<0.001) as compared to premilking values. The teat wall thickness immediately after milking and 1 hour after milking were statistically significantly higher (p<0.001) compared to the premilking size. The analysis of results showed that ultrasonography is a rapid non-invasive and accurate method for determination of characteristics and size of teat structures. It could be used for evaluation of changes occurring in bovine teat after milking - shortening of the teat canal, teat wall thickening and reduction of teat cistern diameter.

The relationship between the milking process phases and the artificial teat reaction have been studied. Milking units with a conventional and tri-circle shape of the pulsation chamber were used. The conclusions are related to the reaction of the teat support and the changes of the time components in the pulsogram. The filling of the milking chamber with an artificial teat reduces the absolute duration of the transitional phases "a" and "c" and prolongs the actual phases "b" and "d" in all the experimental rates.

Abstract. Milking machines equipped with new and used milking liners with a round cross section were studied. The used milking membranes were operated for 3 months on a farm for rearing 60 cows (Holstein cattle) with double milking per day. The experiment involved recording the standard pulsation phases “a”, “b”, “c” and “d” (in absolute units) in the frequency range from 1 Hz to 2.5 Hz, in a vacuum mode of 40 kPa and 50 kPa and at a pulsation ratio of 50/50%. It was found that the transients (phase “a” and phase “c”) are faster and the established phases (phase “b” and phase “d”) are longer in milking units equipped with used milking liners. The conclusions are related to the service life of the milking liners.

Abstract. A comparative study of the pulsation phases in classic milking units was performed. The testing of the same is done in laboratory and field conditions (during milking). The pulsation settings at which the test was performed were pulsation rate 60 min-1 and 90 min-1, ratio 50/50% and vacuum mode 50 kPa. The experiments were performed in the laboratory of “Machine milking” (Department of Agricultural Engineering, Faculty of Agriculture, Trakia University) on a milking installation with a pipe line and on a farm for 60 lactating cows at the same milking installation. It was found that the transients (phases “a” and “c”) are significantly reduced during milking. Respectively, the actual phases (phases “b” and “d”) are significantly increased during the milking process. The conclusions are related to the settings and timely diagnostics of the milking machine.