The objectives were to study the effect of 2 different premilking stimulation regimens, with and without manual forestripping, on teat tissue condition and milking characteristics in dairy cows. In a randomized controlled crossover study, 130 Holstein cows milked 3 times daily were assigned to treatment and control groups. Premilking udder preparation for the treatment group consisted of: (1) predipping with 1% iodine, (2) sequential forestripping of 3 streams of milk per quarter, (3) wiping of teats, and (4) attachment of the milking unit. Premilking udder preparation for the control group was identical except that the forestripping step was omitted. The mean tactile stimulation durations were 16 s and 7 s for the treatment and control group, respectively. The time spent from first tactile stimulus (either forestripping or wiping of teats) to milking unit attachment was kept consistent at 90 s for both groups. The study lasted for 14 d with 2 periods, each consisting of a 2-d adjustment time followed by 5 d of data collection. Machine milking-induced short-term changes to the teat tissue were assessed by palpation and visually. The following milking characteristics were assessed with electronic on-farm milk meters: milk yield (MY), milking unit-on time (MUOT), 2-min MY (2MIN), and time spent in low milk flow rate (LMF). Generalized linear mixed models were used to describe the effect of treatment on the outcome variables. The odds of machine milking-induced short-term changes to the teat tissue were lower for cows that received forestripping compared with cows that were not forestripped (odds ratio = 0.31; 95% confidence interval = 0.22-0.42). Least squares means (95% confidence interval) for cows that were forestripped and animals that were not for-estripped, respectively, were 12.

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The primary objective of our study was to assess the ability of a vacuum recorder to detect the presence of bimodal milk flow curves in dairy cows compared with a portable milk flow meter. In a cross-sectional study, 241 individual cow milking observations were analyzed. We simultaneously collected (1) individual cow vacuum events during milking using portable vacuum recorders, and (2) individual cow milk flow curves by attaching a portable milk flow meter to the same milking unit. Presence of bimodality was assessed with the vacuum recorder visually (BIMVA) and with the gold standard method of a milk flow meter through automatic detection (BIMLA). Kappa statistics revealed moderate agreement between BIMVA and BIMLA [κ, 95% confidence intervals (95% CI) = 0.59 (0.46–0.71)]. Diagnostic test statistics for BIMVA for detection of bimodality indicated moderate performance for sensitivity [0.65 (0.52–0.76)] and positive predictive value [0.71 (0.58–0.82)] and high values for specificity [0.92 (0.87–0.95)] and negative predictive value [0.93 (0.84–0.93)]. We conclude that milking vacuum dynamics are a suitable measure to assess bimodal milk flow curves in dairy cows.

The importance of the end of lactation and the dry period in the dynamics of intramammary infection (IMI) in dairy cattle has long been recognized. In previous studies, gradual cessation of milking has been shown to decrease daily milk production during the last week of lactation and reduce risk of new IMI during the dry period. Although these results support the use of gradual cessation of milking to end lactation as an aid to improve udder health, only a limited number of recent studies have investigated its suitability in high-producing dairy cows. Consequently, gradual cessation has not been implemented widely in the field and no definite regimen has been recommended to dairy producers. However, due to increased intramammary pressure and subsequent tissue damage, abrupt cessation has been shown to be associated with elevated fecal stress hormones and is therefore subject to increasing concerns regarding animal well-being. The objective of this study, therefore, was to investigate the effect of 2 different drying-off protocols (gradual vs abrupt cessation) on the risk of new IMI, milk production, and somatic cell count (SCC) in the subsequent lactation, as well as concentration of fecal glucocorticoid metabolites in dairy cows. We hypothesized that cows that are enrolled in an intermittent milking schedule (i.e., gradual cessation) for the final week of lactation would have a lower risk of new IMI during the dry period, higher milk production, and lower SCC in the subsequent lactation, as well as lower fecal glucocorticoid concentration compared with their herd mates that are milked 3 times daily and dried-off by abrupt cessation.