Table 2.

The effects of selenium yeast supplementation on dry matter intake, milk production and composition.

Item	Treatment1			SEM	P-value
	Control	SY-0.5	SY-5		Treatment	Week	Treatment × Week
Dry matter intake, kg/d	22.4	22.2	22.7	0.13	0.32	<0.01	0.10
Production, kg/d
Milk yield	31.2	30.1	33.2	1.32	0.46	<0.01	0.10
4% FCM2	31.8	29.9	34.9	1.53	0.17	<0.01	0.31
ECM3	35.4	33.4	38.8	1.62	0.17	<0.01	0.24
Protein yield	1.12	1.06	1.21	0.04	0.20	<0.01	0.23
Fat yield	1.29	1.20	1.44	0.07	0.12	<0.01	0.38
Lactose yield	1.49	1.41	1.61	0.06	0.35	<0.01	0.15
Total solids field	4.08	3.45	4.46	0.29	0.19	<0.01	0.21
Total solids-not fat field	2.81	2.67	3.04	0.11	0.27	<0.01	0.19
Composition, %
Protein	3.63	3.54	3.65	0.03	0.60	<0.01	0.53
Fat	4.15	4.02	4.36	0.10	0.45	<0.01	0.84
Lactose	4.74	4.70	4.84	0.04	0.24	<0.01	1.00
Total solids	13.1	12.9	13.4	0.21	0.31	<0.01	0.66
Solids-not fat	9.01	8.93	9.13	0.12	0.19	<0.01	0.94
SCS4	4.48a	4.07a	3.42b	0.11	0.01	0.01	0.08

^a,b Values in the same row with a different superscript differ significantly.

¹Control, SY-0.5 and SY-5 were supplemented with selenium yeast at 0.5 and 5 mg Se/kg DM, respectively.

²4% FCM = 4% fat-corrected milk = 0.4 × Milk yield (kg) + 15.0 × Milk fat yield (kg).

³ECM = energy-corrected milk = 0.327 × Milk yield (kg) +12.95 × Milk fat yield (kg) +7.20 × Milk protein yield (kg).

⁴SCS = somatic cell score = log₂ [SCC (cells per mL)/100,000] + 3.