Short communication: Teat-end shape and udder-level milking characteristics and their associations with machine milking-induced changes in teat tissue condition

Abstract

Machine milking-induced changes in teat tissue condition, such as congestion and edema, have been associated with teat canal openness, penetrability, and thus susceptibility to new intramammary infections and diminished animal well-being. The primary objective of this study was to investigate the association of teat-end shape and machine milking-induced shortterm changes in teat tissue condition. Our secondary objective was to study the association of udder-level milking characteristics and short-term changes. Data from 125 Holstein cows were analyzed in a longitudinal prospective cohort study. Cows were housed in freestall pens with sand bedding, fed a total mixed ration, and milked 3 times per day. Teat-end shape was classified into 3 categories: pointed, flat, and round. Udder-level milking characteristics were obtained from electronic on-farm milk meters. Short-term changes in teat tissue condition after machine milking were assessed visually. Multivariable generalized mixed model analysis showed an association between teat-end shape and short-term changes. Compared with teats with round teat-end shape, the odds ratio (95% confidence interval) for short-term changes was 1.68 (0.53-5.31) and 0.03 (0.004-0.19) in teats with pointed and flat teat-end shape, respectively. There was an association between milking characteristics and short-term changes such that higher milk flow rate during the first 15 s of milking decreased the likelihood of short-term changes. The adjusted probability of short-term changes for a milking observation of a mid-lactation cow and an average first 15-s milk flow rate of 0.5 and 1.5 kg/min was 53. 0% (42.8-63.8) and 32.9% (15.2-57.3), respectively. Our results suggest that teat-end shape may be one of the risk factors that contribute to machine milking-induced short-term changes. Milking characteristics (e.g., first 15-s milk flow rate) may have the potential as a measure to indirectly monitor teat tissue changes associated with machine milking on a daily basis, though further research is needed to validate this hypothesis and to establish thresholds that could serve as on-farm guidelines.

Vacuum Dynamics as an Alternative Method for Detection of Bimodal Milk Ejection in Dairy Cows

“…Our results do not support a measurable relationship between BIM VA , BIM LA , and LDT and STC. The results of the current study contrast with those of a previous study from our group showing an association between udder-level milking characteristics as assessed with electronic on-farm milk meters and STC [40]. Discrepancies in study populations and assessment technique could be variables that account for the differences observed between our previous study and this one.…”

“…This may have had an influence on our outcome measurements, namely bimodality and STC. However, our results are comparable with those of previous studies investigating bimodality [1,9] or STC [40,44]. We therefore believe that if such an influence had existed, it would have been minor.…”

“…For example, several researchers reported that bimodality is positively associated with milking speed [1,41], such that cows with a bimodal milk flow curve had higher maximum milk flow rate [41] or the frequency of bimodality increased with increasing peak milk flow rate [1]. In a recent study, we showed that milkability was highest in cows with flat teat ends [42], which in turn has been reported to decrease the risk of STC [40]. It is therefore possible that in the current study, cows with flat teat ends had a higher risk of bimodality but were less likely to exhibit STC.…”

Feasibility of the use of deep learning classification of teat-end condition in Holstein cattle

“…automated scoring system could facilitate exclusion of the nonlactating quarter from evaluation and thereby improve accuracy. Several research groups showed an association between milking characteristics and machine milking-induced changes in teat tissue condition (Nørstebø et al, 2018;Wieland et al, 2018). Linking cow-or quarter-level milk flow data from electronic on-farm milk meters could therefore further improve the accuracy of image-based classification of teat tissue condition.…”

Graduate Student Literature Review: Understanding the genetic mechanisms underlying mastitis

“…Approaches have included reducing exposure to pathogens by prioritizing improvements to cow housing, ensuring milking hygiene, and minimizing teat lesions (Dodd, 1983;Bartlett et al, 1992). Additional emphasis has been given to milking machine effects and examining the resistance of the teat canal itself to bacterial invasion, considering factors such as overmilking, milk flow, vacuum level, liner slips, and pulsation (Thompson et al, 1978;Natzke et al, 1982;Baxter et al, 1992;Lacy-Hulbert and Hillerton, 1995;Wieland et al, 2018). Research has also focused on the potential dispersal of bacteria in the udder by considering factors such as hand-stripping to remove foremilk and the frequency of udder evacuations (Mein et al, 2004;Shoshani et al, 2017).…”