α-Tocopherol and β-carotene concentrations in feed, colostrum, cow and calf serum in Swedish dairy herds with high or low calf mortality

Table 2 Results of univariable analyses (categorical variables), tested for associations with type of herd: high mortality (HM) or low mortality (LM)

Model/variable	Class	HM	LM	P value^a
Model feed^b (n = 57)
Feeding TMR	Yes	18	21
Feeding TMR	No	9	9	0.88
First harvest grass in feed sample^c	Yes	12	15
First harvest grass in feed sample^c	No	15	12	0.64
Percentage maize silage of total diet (%)	< 20	18	24
Percentage maize silage of total diet (%)	≥ 20	9	6	0.26
Third harvest grass in feed sample^d	Yes	18	16
Third harvest grass in feed sample^d	No	9	11	0.74
Type of herd (HM/LM)		27	30
Model colostrum^b (n = 162)
Breed	SR	15	46
Breed	SH/MB	65	41	0.063
Hours post-partum sample was collected	< 1	19	28
	> 1 ≤ 3	37	30
	> 3–6	24	29	0.15
Milk leakage occurred pre-partum	Yes	6	13
	No	64	74	0.25
	Missing	10	0
Parity	1	20	22
	2	24	34
	3	16	13
	4–8	20	18	0.68
Type of herd (HM/LM)		80	87
Model cow (n = 189)
Breed	SR	14	54
	SH	67	39
	MB	9	6	0.12
Day post partum cow was sampled	2–3	33	40
	4–5	31	36
	6–7	26	23	0.80
Feeding TMR	Yes	18	21
Feeding TMR	No	9	9	0.88
Parity	1	37	39
	2	21	31
	3–8	32	29	0.55
Percentage maize silage of total diet (DM)	Tested in model feed, see above
Type of herd (HM/LM)		90	99
Model calf^b (n = 187)
Age of calf when sampled (days)	2–3	30	42
	4–5	30	33
	6–7	29	23	0.53
Breed	SR	15	52
Breed	SH/MB	74	46	0.052
Total protein (g/L)	≥ 55	59	58
Total protein (g/L)	< 55	30	40	0.52
Transition milk is given (days)	≥ 3	59	88
Transition milk is given (days)	< 3	20	10	0.42
Type of herd (HM/LM)		89	98

SR Swedish Red, SH Swedish Holstein, MB mixed breed
^aTested with univariable logistic regression, with cluster on herd, of its association with type of herd (HM: high mortality; LM: low mortality)
^bOutcome transformed with a natural logarithm (ln) to approximate normal distribution
^cVariable used only for the model “β-carotene concentration in feed”
^dVariable used only for the model “α-tocopherol concentration in feed”

ISSN: 1751-0147