Effect of Somatic Cell Count on Milk Yield and Composition of First and Second Lactation Dairy Cows

Figures & data

Table 1. The effect of number, average and month of lactation on milk yield, somatic cell count and milk composition.

Parameter	LN	ALY							Months					SEM	P
	June	July	August	September	October	November	December	January	February	March		LN	Month	LNxmonth
Milk yield, kg/day	1	27.10	26.73	30.68	28.73	29.72	29.42	28.82	25.51	24.44	26.20	24.24	2.750	<0.001	<0.001	<0.001
2	29.68	37.27	38.03	34.06	34.26	29.92	29.70	25.26	23.96	25.37	22.15
SCC,xl0^3cell/mL	1	246.7	292.23	180.81	123.00	97.84	239.80	381.77	392.50	174.30	148.57	402.33	0.112	0.034	<0.001	0.889
2	303.1	296.60	191.89	307.75	210.71	244.83	278.96	348.33	535.12	213.91	413.83
Total solids, %	1	12.75	12.32	12.49	12.79	12.33	12.71	13.09	12.12	12.93	13.42	13.21	0.074	0.026	<0.001	0.960
2	12.96	12.51	12.52	12.66	12.67	13.03	13.34	12.51	13.18	13.84	13.28
Milk fat, %	1	3.83	3.65	3.84	4.03	3.55	3.81	4.06	2.92	3.84	4.35	4.20	0.067	0.101	<0.001	0.967
2	3.98	3.85	3.77	3.92	3.79	4.01	4.26	3.26	3.99	4.72	4.17
Milk protein, %	1	3.28	3.14	2.97	3.21	3.22	3.28	3.34	3.50	3.43	3.30	3.42	0.005	<0.001	<0.001	0.463
2	3.41	3.13	3.12	3.26	3.35	3.44	3.48	3.54	3.62	3.55	3.52
Milk lactose, %	1	4.67	4.66	4.61	4.66	4.65	4.69	4.78	4.72	4.62	4.64	4.72	0.002	0.002	<0.001	0.952
2	4.62	4.64	4.59	4.60	4.62	4.64	4.64	4.73	4.62	4.50	4.64
Milk urea-N, mmol/L	1	6.69	6.76	7.06	6.58	6.30	6.40	6.51	6.78	6.49	7.08	6.79	0.034	0.141	<0.001	0.622
2	6.59	6.67	6.76	6.36	6.19	6.47	6.62	6.50	6.42	7.32	6.48

LN, lactation number; ALY, average lactation yield; SCC, somatic cell count.

Table 2. The effect of somatic cell count on milk yield and composition.

Parameter	LN	SCC,xl0^3cell/mL				SEM	P
		≤200	201-500	501-999	≥1000		LN	SCC	LNxSCC
Milk yield, kg/day	1	26.78	26.76	25.50	24.00	2.646	0.054	<0.001	0.346
2	30.93	29.49	29.41	25.68
Total solids, %	1	12.60	12.99	12.80	13.10	1.026	0.237	0.044	0.705
2	12.87	13.11	13.35	13.04
Milk protein, %	1	3.23	3.33	3.42	3.46	0.544	0.153	<0.001	0.742
2	3.35	3.45	3.45	3.50
Milk fat, %	1	3.75	3.95	3.70	3.99	0.973	0.104	0.321	0.762
2	3.91	4.08	4.30	4.22
Milk lactose, %	1	4.68	4.67	4.69	4.68	0.420	<0.001	<0.001	<0.001
2	4.65	4.61	4.56	4.32
Milk urea-N, mmol/L	1	6.65	6.83	6.63	6.47	0.891	0.802	0.046	0.620
2	6.54	6.72	6.87	6.33

LN, lactation number; SCC, somatic cell count.

Table 3. Correlation of somatic cell count with milk yield and composition.

Parameter	Milk yield	Total solids	Milk fat	Milk protein	Milk lactose	Milk urea-N
SCC	-0.251^**	0.164^*	0.103^*	0.291^*	-0.206^**	0.005

SCC, somatic cell count.

**P<0.01;

*P<0.05.