Case-control study on factors associated with a decreased milk yield and a depressed health status of dairy herds in northern Germany

Table 2 Descriptive and single-factorial analyses of risk factors for health and performance problems in dairy farms in Northern Germany (quantitative variables; no missing values in either status group)

Variable	N	Cases			N	Controls			Single factorial analyses
Variable	N	Mean	Median	CV	N	Mean	Median	CV	OR	LCL	UCL	P
Crude fiber
% of the herd with fat-protein-quotient < 1 in the DHI data	45	7.8	6.7	81.5	47	8.7	7.3	70.2	0.98	0.91	1.05	0.5228
Ratio of roughage in the complete diets felc¹ based on DM content	45	58.6	58.6	15.8	47	58.2	58.0	12.4	1.01	0.97	1.05	0.5035
Energy density
Energy density in the roughage diets in MJ NEL/kg DM felc¹	45	6.3	6.3	3.2	47	6.4	6.4	3.5	0.06	0.01	0.51	0.0091
Energy density in the complete diets in MJ NEL/kg DM felc¹	45	6.9	6.9	3.3	47	7.0	7.0	2.7	0.12	0.01	1.02	0.0519
Quantity of feed
Roughage per cow and day in kg DM felc¹	45	13.4	13.2	17.4	47	14.3	14.2	12.7	0.81	0.65	1	0.0541
Confounder
Herd size (lactating and dry cows)	45	118.9	108.0	58.9	47	144.8	120.0	47.0	0.99	0.99	1.00	0.0867

ISSN: 1746-6148