Short communication: Associations between teat dimensions and milking-induced changes in teat dimensions and quarter milk somatic cell counts in dairy cows

Bacterial populations of teat skin are associated with risk of intramammary infection and may be influenced by anatomical characteristics of teats. The objective of this study was to evaluate associations of selected anatomical characteristics of teats with bacterial counts of teat skin of cows exposed to different types of bedding. Primarily primiparous Holstein cows (n = 128) were randomly allocated to 4 pens within a single barn. Each pen contained 1 type of bedding [new sand (NES), recycled sand (RS), deep-bedded manure solids (DBMS), and shallow-bedded manure solids over foam core mattresses (SBMS)]. During a single farm visit udders (n = 112) were scored for hygiene and 1 front (n = 112) and 1 rear teat (n = 111) of each enrolled cow were scored for hyperkeratosis (HK). Teat length, teat barrel diameter, and teat apex diameter were measured and teat skin swabs were systematically collected for microbiological analysis. Linear type evaluation data for udders of each cow were retrieved for each cow. Teat position (front or rear) was associated with occurrence of clinical mastitis during the 12 mo before the farm visit and more cases occurred in front quarters. The proportion of udders that were classified as clean (score 1 or 2) was 68, 82, 54, and 95% for cows housed in pens containing NES, RS, SBMS, and DBMS, respectively. No association was found between HK score and teat position and no association was found between HK score and teat skin bacterial count. Bacterial counts of teat skin swabs from front teats of cows in pens containing RS and SBMS were significantly less than those of rear teats of cows in pens containing DBMS or NES. Teat skin bacterial counts were significantly greater for swabs obtained from teats of cows with udder hygiene scores of 3 and 4 as compared with swabs obtained from cows with cleaner udders. Of all udder conformation traits evaluated, only narrower rear teat placement was positively associated with bacterial counts on teat skin.

Section: Introductionmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Anatomical characteristics of teats and premilking bacterial counts of teat skin swabs of primiparous cows exposed to different types of bedding

Guarín

Baumberger

Ruegg

2017

“…Machine milking-induced short-term changes of teat tissue condition are defined as tissue responses to a single milking (Mein et al, 2001) and can be discriminated into congestion (intravascular accumulation of fluids) and edema (extravascular accumulation of fluids; Hamann and Mein, 1990). Short-term changes have been investigated in multiple studies using different techniques, including visual assessment (Hillerton et al, 2000), a modified spring-loaded caliper (Hamann and Mein, 1988), a 2-dimensional vision-based measuring device (Zwertvaegher et al, 2013), infrared thermography (Paulrud et al, 2005), and ultrasonography (Neijenhuis et al, 2001a). These short-term changes have been related to teat canal openness, penetrability, and susceptibility to new IMI (Zecconi et al, 1992;Neijenhuis et al, 2001a;Paulrud et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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

Melvin

Heuwieser

Virkler

et al. 2019

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.

“…The canals of congested teats have been shown to close more slowly after milking (Neijenhuis et al, 2001), and this delayed closure of the teat canal is thought to result in a longer window of opportunity for mastitis, causing bacteria to pass through the teat canal (Mein et al, 1987;Zecconi et al, 1992;Gleeson et al, 2004). Thicker teats postmilking compared with premilking are associated with higher quarter SCC (Zwertvaegher et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Effect of pulsation rest phase duration on teat end congestion

Upton

Penry

Rasmussen

et al. 2016

The objective of this study was to quantify the effect of d-phase (rest phase) duration of pulsation on the teat canal cross-sectional area during the period of peak milk flow from bovine teats. A secondary objective was to test if the effect of d-phase duration on teat canal cross-sectional area was influenced by milking system vacuum level, milking phase (b-phase) duration, and liner overpressure. During the d-phase of the pulsation cycle, liner compression facilitates venous flow and removal of fluids accumulated in teat-end tissues. It was hypothesized that a short-duration d-phase would result in congestion of teat-end tissue and a corresponding reduction in the cross-sectional area of the teat canal. A quarter milking device, designed and built at the Milking Research and Instruction Laboratory at the University of Wisconsin-Madison, was used to implement an experiment to test this hypothesis. Pulsator rate and ratios were adjusted to achieve 7 levels of d-phase duration: 50, 100, 150, 175, 200, 250, and 300ms. These 7 d-phase durations were applied during one milking session and were repeated for 2 vacuum levels (40 and 50kPa), 2 milking phase durations (575 and 775ms), and 2 levels of liner overpressure (9.8 and 18kPa). We observed a significant reduction in the estimated cross-sectional area of the teat canal with d-phase durations of 50 and 100ms when compared with d-phase durations of 150, 175, 225, 250, and 300ms. No significant difference was found in the estimated cross-sectional area of the teat canal for d-phase durations from 150 to 300ms. No significant interaction was observed between the effect of d-phase and b-phase durations, vacuum level, or liner overpressure.