Increased teat wall thickness in response to machine milking

Transiently increased teat wall thickness in response to machine milking has been documented by various methods, including ultrasound. However, correlative ultrasonography and histology detect the origin of this phenomenon is lacking. The first goal present study was evaluate compare milking-related changes tissue 2 breeds dairy cows (11 Simmental 3 Holstein) using B-mode ultrasonography. Additionally, observed were compared with ultrasonographic findings a Holstein cow periparturient udder edema. Finally, corresponding histological sections teats analyzed those from lactating nonmilked Angus cow. We hypothesized that mechanical load both stretching vacuum during phases open cup liner compression closed results transient congestion blood vessels wall. barrel 1 front each scanned immediately before after (system vacuum: 42 kPa; pulsation rate: 60 cycles/min; ratio: 65:35). Shortly (33 ± 6 min), Simmentals slaughtered, their removed processed for investigation light microscopy. Ultrasonography revealed anechoic tubular structures mainly inner half Histological examination these be thick-walled veins. left hind cow, collected prepared identically cows, showed same features. Ultrasonographic measurements diameter veins significantly matching images milking. This effect most pronounced cows. Similarly, very prominent neither milked nor provided any evidence edematous extravasation on or histology. These corroborated our hypothesis increase size main reason thickening walls