Dam characteristics associated with pre-weaning diarrhea in mink (Neovison vison)

Table 3 Associations between litter PWD status and individual dam- and litter-level risk factors after controlling for farm and design effects

Exposure variable	N	Fixed effect of the exposure variable in the model					Fixed effect of the extraneous design variable
		PWD+	PWD−	OR	CI_95% of OR	P	High vs. low farm PWD prevalence^a
		PWD+	PWD−	OR	CI_95% of OR	P	OR	CI_95% of OR	P
Only farm PWD status in the model	70			–	–	–	8.61	2.29; 32.30	0.002
Female characteristics
Age of dam (1-year/> 1-year)	70^b	25/4	20/21	8.54	1.97; 36.98	0.005	10.10	2.55; 40.05	0.002
Number of kits observed after birth (> 5/≤ 5)	70	15/14	2/39	25.00	3.91; 159.68	0.001	8.88	2.13; 37.00	0.004
Body mass index^b (≤ 17.7/> 17.7)	70	14/15	24/17	0.62	0.19; 2.02	0.42	8.80	2.31; 33.56	0.002
Number of active glands per mink kit (≤ 1.5/> 1.5)	70	15/14	10/31	4.92	1.29; 18.79	0.02	11.14	2.69; 46.10	0.001
Weight of mammary gland tissue per kit (g) (> 12.19/≤ 12.19)	68^c	8/20	18/22	2.02	0.58; 7.00	0.26	9.61	2.46; 37.5	0.002
Bacteriology of mammary gland
Bacterial growth of mammary gland (±)	70	6/23	3/38	9.08	1.25; 65.71	0.03	13.19	3.03; 57.38	0.001
Histology of mammary gland
Infiltration of MNL (more/few)	70	13/16	16/25	0.80	0.24; 2.68	0.72	9.16	2.32; 36.18	0.002
Infiltration of PNL (present/absent)	70	6/23	7/34	1.82	0.37; 9.01	0.45	9.30	2.36; 36.61	0.002
Mammary tissue oedema (±)	70	11/18	15/26	0.72	0.21; 2.45	0.60	9.22	2.35; 36.18	0.002
Mammary tissue calcification (> 2/≤ 2 per slide)	70	1/28	1/40	2.36	0.07; 76.69	0.62	8.91	2.29; 34.63	0.002
Mammary corpora amylacea (> 4/≤ 4 per slide)	70	3/26	7/34	0.72	0.12; 4.36	0.72	8.56	2.24; 32.68	0.002
Excess fibrous connective tissue (±)	70	2/27	2/39	0.47	0.05; 4.94	0.52	9.76	2.42; 39.45	0.002

All models included Farm ID as random effect variable. All models included two fixed effects explanatory variables of which the extraneous design variable “Farm PWD status” with high farm prevalence vs. low farm prevalence of litters with PWD was forced into each model and one exposure variable of interest, e.g. “Age of dam”. Each line represents one model
BMI body mass index, MNL mononuclear leucocytes, PNL polymorphonuclear leucocytes
^a >/<10% prevalence affected litters
^bThe 70 litters in the analysis are dichotomized according the the exposure level and disease status. Thus, as an example, the model with “Age of dam” had 25, 4, 20 and 21 litters in the categories and sums up to 70
^cInformation was missing for two dams

ISSN: 1751-0147