Machine milking–induced changes in teat canal dimensions as assessed by ultrasonography

Abstract

Changes in teat canal diameter as induced by machine milking are thought to be related to teat canal penetrability and susceptibility to new intramammary infections. The objective of this study was to describe the effects of machine milking on teat canal dimensions as assessed by ultrasonography and to evaluate postmilking changes of teat canal dimensions throughout an 8-h milking interval. Ultrasonographic images were taken of the left front and right hind teats of 80 Holstein cows milked 3 times per day. Imaging occurred before attachment of the milking unit after completion of premilking udder preparation (t−1), immediately after removal of the milking unit (t0), and then every hour after milking until 8 h had elapsed (t1 to t8). Teat canal length and teat canal diameter (at the proximal, middle, and distal regions) were measured. General linear mixed model analysis indicated differences in the relative change of teat canal length (compared with t−1) with least squares means (LSM) and 95% confidence interval (95% CI) of 11.1% (8.7-13.4%) after machine milking (t0). Teat canal length decreased throughout the 8-h milking interval but remained elevated relative to t−1. Teat canal diameter at the proximal and middle regions increased near the end of the milking interval, whereas that at the distal region did not change meaningfully during the 8 h of observation. Our findings suggest that the teat canal and its surrounding tissue is in a state of near-constant remodeling in cows milked 3 times daily. Future work is warranted to study the association between ultrasonographically assessed changes of teat canal dimensions after machine milking and teat canal penetrability to mastitis-causing pathogens.

Delta thermal radiomics: An application in dairy cow teats

“…Although this radiomic feature is not the same as the 3-dimensional teat surface area, it does provide a surrogate measurement of area as seen from the camera. This observation is consistent with results from previous studies (Guarín and Ruegg, 2016;Melvin et al, 2019) and is most likely attributable to longitudinal shear forces that are applied to the teat during milking (Williams and Mein, 1982). Elongation of teats after milking was higher and did not reach our level of significance (P < 0.03) but it demonstrated a substantial effect size (d > 1.20), suggesting that detection of morphological changes via thermal radiomics is plausible.…”

A randomized trial to study the effect of automatic cluster remover settings on milking performance, teat condition, and udder health

“…Recent developments in milking machine settings in the industry support an increased threshold, and a cluster remover take-off milk flow threshold of up to 1 kg/min has been suggested (Besier and Bruckmaier, 2016). This trend was further supported by a recent field study on a commercial dairy farm in Michigan (Erskine et al, 2019) that applied a threshold of 1.1 kg/min, as well as studies from our own group on farms that applied a threshold of 1.3 kg/min (Wieland et al, 2017;Melvin et al, 2019). To our knowledge, no studies have investigated the effect of such high ACR settings on milking performance.…”

Technical note: Development and evaluation of a standardized technique to assess blood perfusion in teats of dairy cows using power Doppler ultrasonography

“…Measures to further improve precision include modification of the standoff (i.e., container or standoff medium), training of operators, and further standardization of image analysis (e.g., automatized determination of the region of interest subjected to computational analysis with PixelFlux). Recently, we showed that recovery of teat tissue alterations that result from machine milking can last several hours or exceed the 8-h milking interval in cows milked 3 times a day (Melvin et al, 2019). In the current study, we performed teat scanning between 3 and 6 h after milking, which likely resulted in scanning of teats in a state of remodeling.…”