A longitudinal prospective cohort study investigating the association of premilking stimulation and teat-end shape on milking characteristics and teat tissue condition in dairy cows

Table 2 Unadjusted regression coefficients, SE, unadjusted odds ratios, and 95% CI for independent variables tested for association with machine milking-induced short-term changes to the teat condition from univariable generalized linear mixed models from 384 milking observations of 129 cows

Explanatory variable	β^a (SE)	unadj.OR^b (95% CI)	p
Milking session			0.001
Milking #1	0.30 (0.35)	1.34 (0.68–2.64)
Milking #2	−0.97 (0.34)	0.38 (0.19–0.75)
Milking #3	-Referent-
Parity			0.06
1st	1.10 (0.51)	3.01 (1.10–8.24)
2nd	0.01 (0.58)	1.02 (0.33–3.17)
≥ 3rd	-Referent-
DIM^c			0.003
≤ 100	1.84 (0.55)	6.28 (2.12–18.59)
101–200	0.72 (0.55)	2.05 (0.70–5.99)
> 200	-Referent-
TES^d			0.06
Pointed	0.90 (0.65)	2.45 (0.68–8.75)
Flat	−1.41 (0.79)	0.24 (0.05–1.15)
Round	-Referent-
TMY^e	0.12 (0.05)	1.13 (1.02–1.25)	0.02
STIM^f	0.02 (0.37)	1.02 (0.49–2.11)	0.95
LAG^g	−0.15 (0.07)	0.86 (0.74–1.01)	0.06

^aUnadjusted linear regression coefficient
^bUnadjusted odds ratio
^cStage of lactation (days in milk)
^dTeat-end shape. Classified as follows: pointed = 2 or more pointed teats, flat = 2 or more flat teats, round = 3 or 4 round teats
^eTMY = Total milk yield (kg)
^fStimulation time (s)
^gPreparation lag time (s), time between first teat stripping and milking unit attachment
^e-gOdds ratios are for each 1-unit increase, TMY: 1 kg; STIM: 10 s; LAG: 10 s

ISSN: 1746-6148