Comparison of milk and grass composition from grazing Irish dairy herds with and without milk fat depression

Table 4 Mean pasture chemical composition and FA composition of HMF, MMF and LMF herds

Item	HMF¹	MMF¹	LMF¹	S.E.M²
Pre-grazing herbage mass (kg/DM ha)	1821	2012	1660	124.0
DM (%)	17.41	17.56	17.29	0.492
Chemical composition (% of DM)
Crude protein	17.66	18.22	18.33	0.756
NDF	43.40	44.93	45.25	0.782
ADF	19.84	20.89	20.98	0.465
Ash	8.37	8.41	8.60	0.232
WSC	5.65	4.78	4.01	0.571
Oil—Ether extract	3.03	2.91	2.74	0.135
FA (mg/g DM)
Total FA (mg/g DM)	28.25	26.54	25.46	1.233
FA (g/kg of total FA)
C4:0	0.11	0.12	0.12	0.011
C6:0	0.19^a	0.22^a,b	0.27^b	0.025
C8:0	0.15^a	0.22^b	0.22	0.025
C12:0	0.28	0.34	0.36	0.032
C14:0	0.63	0.66	0.75	0.041
C15:0	0.17	0.20	0.21	0.014
C16:0	18.64^a	20.21^a,b	20.89^b	0.685
C16:1c9	0.22	0.25	0.28	0.020
C17:0	0.22^a	0.24^a,b	0.26^b	0.015
C18:0	1.66^a	1.82^a,b	2.01^b	0.096
C18:2c 9,12	14.80	15.23	14.78	0.349
C18:3c6,9,12	0.10	0.12	0.15	0.021
C18:3c9,12,15	57.81	54.65	53.72	1.400
C20:0	0.38	0.40	0.42	0.027
C21:0	0.16	0.19	0.20	0.025
C22:0	0.63	0.65	0.71	0.030
C24:0	0.44	0.42	0.49	0.024
C24:1c15	0.13	0.15	0.16	0.008
Total Saturated FA	23.96^a	26.19^a,b	27.55^b	1.017
Total MUFA	3.00^a	3.29^a,b	3.65^b	0.201
Total PUFA	72.72^a	70.41^a,b	68.71^b	1.195
Total Unsaturated FA	75.81^a	73.86^a,b	72.30^b	1.143
Total Omega 3 FA	57.91	54.75	53.81	1.399
Total Omega 6 FA	14.99	15.45	15.01	0.349
Total Omega 7 FA	0.68	0.71	0.75	0.045
Total Omega 9 FA	2.36^a	2.56^a,b	2.86^b	0.158
Ratio Omega 3:Omega 6	3.99	3.64	3.68	0.163
Ratio Omega 6:Omega 3	0.27	0.28	0.28	0.012

¹HMF (> 3.95% milk fat) = High milk fat herds, MMF (3.31 – 3.94% milk fat) = Medium milk fat herds, LMF = Low milk fat herds (< 3.30% milk fat)
²S.E.M = Standard error of the mean
^a,b,c, Means in the same row with different superscripts differ (P < 0.05)

ISSN: 2046-0481