Effects of zinc supplementation on growth performance, blood metabolites and lameness in young Holstein bulls

Figures & data

Table 1. Composition of basal diet.

	Total mixed ration
Ingredient	Percentage of DM
Corn silage	7.5
Wheat straw	2
Barley (milled)	54
Potato	12
Cottonseed meal	3
Sunflower meal	4.78
Wheat bran	4
Rice bran	6
Beet pulp	2
Molasses	1.5
Zeolite	1.5
Urea	0.28
Calcium carbonate	0.56
Salt	0.28
Vitamin premix^a	0.3
Mineral premix^b	0.3
Chemical composition	Percentage of DM
CP	13.25
NDF	29.25
ADF	12.06
Ether extract	3.04
Ca	0.63
P	0.24
Mg	0.31
S	0.14
	mg/kg DM
Cu	4.7
Zn	44.8
Mn	59
Fe	30.2
Mo	1.2
^aContained per kilogram of premix: 500,000 IU of vitamin A, 100,000 IU of vitamin D and 0.1 g of vitamin E.
^bContained per kilogram of premix: 180 g Ca, 90 g P, 20 g Mg, 60 g Na, 2 g Mn, 3 g Fe, 0.3 g Cu, 3 g Zn, 0.1 g Co, 0.1 g Se, 0.1 g I, 3 g antioxidant.

Table 2. Least squares means and standard errors of growth performance and DM digestibility for young Holstein bulls fed different diets.^a

Variable	Control	Zn	P value
DMI (kg/d)
Day 0–28	9.92	9.72	0.72
Day 28–56	10.94	10.65	0.97
Day 0–56	10.43	10.19	0.95
ADG (kg)
Day 0–28	1.46	1.18	<0.01
Day 28–56	1.29	1.10	<0.01
day 0–56	1.37	1.14	<0.01
G:F
Day 0–28	0.14	0.12	<0.001
Day 28–56	0.11	0.10	<0.001
Day 0–56	0.13	0.11	<0.001
DM digestibility (%)	69.75	58.07	<0.001
^aDiets included (1) the basal diet (control); (2) basal diet plus 150 mg of Zn/kg of DM as ZnSO4.

Table 3. Least squares means and standard errors of metabolic profile for young Holstein bulls fed different diets containing a Zn supplementation of 0 or 150 ppm.

Variable	Control	Zn	P value
Plasma total protein (mg/100 ml)	4.9	5.5	<0.01
Plasma albumin (mg/100 ml)	2.9	3.2	<0.05
Plasma ALP (U/L)	97.6	107.3	<0.001
Serum cholesterol (mg/100 ml)	97.7	91.7	<0.01
Serum urea nitrogen (mg/100 ml)	11.8	13.2	<0.01
Serum Zn (µg/100 ml)
Day 0	89.2	90.8	0.85
Day 28	83	101	0.1
Day 56	147.8	194.4	0.06
Serum Cu (µg/100 ml)
Day 0	94	91.4	0.97
Day 28	92.6	108.6	0.35
Day 56	117	127.2	0.6
Liver Zn (mg/kg DM)	164	183.5	<0.05
ALP, alkaline phosphatase.

Table 4. Probabilities of main effects and interactions on serum Zn and Cu of young Holstein bulls.

Variables	Zn	Time	Time×Zn
Serum Zn	0.89	<0.01	0.65
Serum Cu	0.19	<0.01	<0.05

Table 5. Probabilities of main effects on the presence of claw disorders of young Holstein bulls.

Lameness	Sole disorder	White line disorder	Inter-digital disorder
<0.05	0.94	0.94	0.29

Table 6. Associations between treatments and the presence of claw disorders in young Holstein bulls.

	Lameness		Sole disorder		White line disorder		Inter-digital disorder
	OR	CLL–CLU	OR	CLL–CLU	OR	CLL–CLU	OR	CLL–CLU
Control	2.7	0.99–7.43	>999.9	<0.001– > 999.9	>999.9	<0.001– > 999.9	1.75	0.61–5.01
Zn	1		1		1		1
OR, odds ratio; CLL, lower confidence limit; CLU, upper confidence limit; p =0.05.