Flock-level risk factors for outbreaks of infectious arthritis in lambs, Norway 2018

Table 3 Description of variables for management at lambing tested in the univariable screening (Chi²-test)

Variable	Categories	Total		Case flocks (n = 84)		Control flocks (n = 1414)
Variable	Categories	n	%	n	%	n	%	P-value
Observed infections around ear tag^a	No (never/rarely)	1103	73.7	44	52.4	1059	75.0	< 0.0001
Observed infections around ear tag^a	Yes (sometimes, often)	393	26.3	40	47.6	353	25.0
Routines for colostrum supply^b	Observe that they suck, not using stomach tubes	504	33.7	11	13.1	493	34.9	< 0.0001
	Observe that they suck, use stomach tubes routinely/when needed	931	62.2	67	79.8	864	61.1
	Not consistent, no clear routines	62	4.1	6	7.1	56	4.0
How often are stomach tubes used for colostrum supply^{a, b}	Not using stomach tubes	550	36.8	15	17.9	535	37.9	< 0.0001
	Sometimes (1–10% of the lambs)	776	51.9	49	58.3	727	51.5
	Relatively often (> 10% of the lambs)	170	11.4	20	23.8	150	10.6
Disinfection of navels^a	Never/rarely, sometimes	633	42.3	22	26.2	611	43.2	0.002
Disinfection of navels^a	Yes	864	57.7	62	73.8	602	56.8
Age at ear tagging^a	1 day	746	49.9	47	56.0	699	49.5	0.011
	2 days	370	24.8	27	32.1	343	24.3
	≥ 3 days	379	25.4	10	11.9	369	26.2
Statement: as far as possible the ewe and her lambs are left in peace during and immediately after lambing^a	Fully agree	954	64.1	43	51.1	911	64.8	0.017
	Partly agree/disagree	535	35.9	40	48.2	495	35.2
% of ewes needing assistance during lambing^a	0–10%	443	30.2	16	19.3	427	30.9	0.031
	11–20%	430	29.3	23	27.7	407	29.4
	> 20%	594	40.5	44	53.0	550	39.7
Use of disinfectant on ear tag	No/sometimes	908	61.1	54	65.9	854	60.8	0.36
Use of disinfectant on ear tag	Yes	578	38.9	28	34.2	550	39.2

^aTested in multivariable model
^bNot tested in the multivariable model due to collinearity with another variable (with the same letter)

ISSN: 1751-0147