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

Abstract

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.

Risk factors for delayed milk ejection in Holstein dairy cows milked 3 times per day

“…Evidence also suggests that, under certain circumstances, delayed milk ejection can cause reduced milk yield. The underlying concept has been recently described by Erskine et al (2019) and seconded by work from our group (Wieland et al, 2021). However, the reader should keep in mind that a cause-effect relationship cannot be inferred from this observational study.…”

Comparison of Sensor-Based and Audible Detection of Milking Liner Slips during Machine Milking of Dairy Cows

“…Data for trial 2 were collected during 15 visits (Teaching Dairy Barn, 11 visits during the 11:00 a.m. milking session; commercial dairy, 4 visits during the 9:00 a.m. milking session). Individual cow vacuum events were collected during milking using VaDia (BioControl, Rakkestad, Norway) vacuum recorders as previously described [ 11 ]. For this purpose, 4 VaDia devices were installed at the first 2 stalls on each parlor side at the Teaching Dairy Barn, and 10 VaDia devices were installed at 10 consecutive stalls at the commercial dairy farm.…”

The Association of Delayed Milk Ejection with Milking Performance in Holstein Cows in a Large Dairy Herd with Suboptimal Premilking Teat Stimulation

“…They found that cows with DME yielded 1.8–3.1 kg less milk per milking session than cows without DME [ 11 ]. In a study conducted at five dairy farms with a thrice-daily milking schedule in New York, USA [ 12 ], our group analyzed data from 241 cow milking observations and revealed that cows with a bimodal milk flow curve produced 1.3 kg less milk per milking session than those with a unimodal milk flow curve. Bruckmaier and Blum used 12 cows to study the effect of premilking stimulation on milk ejection and milk flow [ 4 ].…”

“…Although these studies have shown that DME can have a negative impact on milking performance in dairy cows, this evidence is limited. For instance, the assessment of the association between DME and milking performance in previous studies was based on a single milking observation [ 4 , 11 , 12 ]. However, some cows may exhibit DME in every milking session, i.e., chronic DME [ 13 ], and the effect size of the association of DME with milking performance could differ according to the frequency of DME events.…”

“…Moore-Foster et al showed that in larger herds (≥300 cows), the total stimulation duration was reduced by half compared to that in smaller herds [ 16 ]. Previous work from our group has shown that the preparation lag time in large dairy operations can be as short as 57 s [ 12 ].…”