Forage preservation (grazing vs. hay) fed to ewes affects the fatty acid profile of milk and CPT1B gene expression in the sheep mammary gland

Table 1 Chemical composition (% of dry matter, DM) and fatty acid content (in % of total fatty acid methyl esters, FAME) of pasture hay, fresh pasture grazed and alfalfa pellets fed to Churra Tensina ewes during the peripartum period ¹

Diet	HAY	GRE
Diet	pasture hay	fresh pasture grazed	alfalfa pellets²
*Chemical composition*
Dry matter M (DM, % of fresh matter)	87.5	18.9	93.3
Crude protein, CP	12.0	20.1	15.7
Neutral detergent fibre, NDF	50.4	42.3	35.5
Acid detergent fibre, ADF	26.8	21.6	23.8
*Fatty acids*
C12:0	0.38	0.23	0.66
C14:0	0.65	0.68	1.14
C16:0	14.13	15.54	13.94
C16:1 cis-9	0.40	0.77	0.21
C17:0	0.73	0.27	0.32
C18:0	3.35	3.02	2.80
C18:1 n-9	3.38	2.98	3.71
C18:1 trans-11 (VA)	0.11	0.20	0.02
C18:2 cis-9 cis-12	7.53	8.51	18.65
C18:3 n-6	1.94	0.54	0.30
C18:3 n-3	14	21.89	18.90
C20:0	18.82	23.44	23.01
SFA	38.60	43.19	37.76
MCFA	1.03	0.91	1.80
LCFA	36.30	42.00	39.75
UFA	27.36	34.89	45.90
MUFA	3.89	3.95	3.94
PUFA	23.47	30.94	41.96
PUFA n-6	9.47	9.05	18.95
PUFA n-3	14	21.89	23.01
n-6/n-3	0.68	0.41	0.82
UFA/SFA	0.71	0.81	1.22

¹SFAs (saturated fatty acids) were calculated as the sum of C12:0 + C14:0 + C16:0 + C17:0 + C18:0 + C20:0; MCFAs (medium-chain fatty acids) were calculated as the sum of C12:0 + C14:0; LCFAs (long-chain fatty acids) were calculated as the sum of C16:0 + C18:0 + C20:0; UFAs (unsaturated fatty acids) were calculated as the sum of (MUFA + PUFA); MUFAs (monounsaturated fatty acids) were calculated as the sum of (C16:1 + C17:1 + C18:1n-9 + C18:11n-7 + C20:1); PUFAs (polyunsaturated fatty acids) were calculated as the sum of (C18:2 t-t + C18:2c-c + C18:3n-6 + C18:3n-3 + CLA + C20:2 + C20:3 + C20:4 + C20:5 + C22:5 + C22:6).
²Supplement during 11 days in the pre-partum grazing ewes, when snow limited pasture availability.

ISSN: 1746-6148