title: Estimating teat canal cross-sectional area to determine the effects of teat-end and mouthpiece chamber vacuum on teat congestion.
abstract: The primary objective of this experiment was to assess the effect of mouthpiece chamber vacuum on teat-end congestion. The secondary objective was to assess the interactive effects of mouthpiece chamber vacuum with teat-end vacuum and pulsation setting on teat-end congestion. The influence of system vacuum, pulsation settings, mouthpiece chamber vacuum, and teat-end vacuum on teat-end congestion were tested in a 2×2 factorial design. The low-risk conditions for teat-end congestion (TEL) were 40 kPa system vacuum (Vs) and 400-ms pulsation b-phase. The high-risk conditions for teat-end congestion (TEH) were 49 kPa Vs and 700-ms b-phase. The low-risk condition for teat-barrel congestion (TBL) was created by venting the liner mouthpiece chamber to atmosphere. In the high-risk condition for teat-barrel congestion (TBH) the mouthpiece chamber was connected to short milk tube vacuum. Eight cows (32 quarters) were used in the experiment conducted during 0400 h milkings. All cows received all treatments over the entire experimental period. Teatcups were removed after 150 s for all treatments to standardize the exposure period. Calculated teat canal cross-sectional area (CA) was used to assess congestion of teat tissue. The main effect of the teat-end treatment was a reduction in CA of 9.9% between TEL and TEH conditions, for both levels of teat-barrel congestion risk. The main effect of the teat-barrel treatment was remarkably similar, with a decrease of 9.7% in CA between TBL and TBH conditions for both levels of teat-end congestion risk. No interaction between treatments was detected, hence the main effects are additive. The most aggressive of the 4 treatment combinations (TEH plus TBH) had a CA estimate 20% smaller than for the most gentle treatment combination (TEL plus TBL). The conditions designed to impair circulation in the teat barrel also had a deleterious effect on circulation at the teat end. This experiment highlights the importance of elevated mouthpiece chamber vacuum on teat-end congestion and resultant decreases in CA.
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, Madison 53705. Electronic address: penry@wisc.edu.
authors.forename: J F
authors.initials: JF
authors.lastname: Penry
authors.affiliation: Animal and Grassland Research and Innovation Centre, Teagasc Moorepark Fermoy, Co. Cork, Ireland P61P302.
authors.forename: J
authors.initials: J
authors.lastname: Upton
authors.affiliation: Scientific consultant, Werribee South, Australia 3030.
authors.forename: G A
authors.initials: GA
authors.lastname: Mein
authors.affiliation: Department of Engineering, Aarhus University, Denmark, 8000.
authors.forename: M D
authors.initials: MD
authors.lastname: Rasmussen
authors.affiliation: The Dairy Group, Taunton, United Kingdom TA12PX.
authors.forename: I
authors.initials: I
authors.lastname: Ohnstad
authors.affiliation: Department of Biological Systems Engineering, University of Wisconsin-Madison, Madison 53705.
authors.forename: P D
authors.initials: PD
authors.lastname: Thompson
authors.affiliation: Department of Biological Systems Engineering, University of Wisconsin-Madison, Madison 53705.
authors.forename: D J
authors.initials: DJ
authors.lastname: Reinemann
mesh_terms: D000818:Animals; D002417:Cattle; D003131:Combined Modality Therapy; D003612:Dairying / Q000295:instrumentation* / Q000379:methods; D005260:Female; D007774:Lactation; D008321:Mammary Glands, Animal / Q000502:physiology / Q000503:physiopathology*; D008893:Milk Ejection / Q000502:physiology; D014618:Vacuum
keywords: congestion; peak milk flow; pulsation; teat barrel; teat end; vacuum