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1417
Alternative forage crops modify the composition and content of bovine milk fatty acids

Thursday, July 21, 2016: 2:30 PM
155 F (Salt Palace Convention Center)
Laura M Cersosimo , University of Vermont, Burlington, VT
Rinske Tacoma , University of Vermont, Burlington, VT
Sabrina Greenwood , University of Vermont, Burlington, VT
Kelsey Juntwait , University of New Hampshire, Durham, NH
Andre F. Brito , University of New Hampshire, Durham, NH
Jana Kraft , University of Vermont, Burlington, VT
Abstract Text:

Bioactive fatty acids (FA) found in milk have been linked to human health benefits. Alternative forage crops (AFC) include small grains, warm-season grasses and legumes that can potentially enhance forage production. The objective of this study was to determine if traditional pasture strip-tilled with AFC (treatment, TRT) would alter the composition (g/100g FA) and content (g/kg milk) of milk FA compared with traditional grass-legume pasture (control, CON). Two 21-d experiments, spring (SPR) and summer (SUM), were conducted using 16 lactating Jersey cows (SPR, 85 ± 46 DIM; SUM, 143 ± 58 DIM). Cows were divided into two groups and offered 60% TMR (DM basis) and 40% pasture as AFC or traditional. SPR AFC included barley, wheat, rye, triticale, and hairy vetch (2.4% diet DM), while SUM AFC included buckwheat, chickling vetch, and oat (10.0% diet DM). From d 19-21 of each experiment, milk samples were collected during four consecutive milkings. Forage and milk FA were analyzed via gas-liquid chromatography. Differences between least-squares means were evaluated using the student’s t test (JMP Pro 12). SPR forage FA (% total) included CON (total n-3 FA: 30.1%; total n-6 FA: 35.2%) and TRT (total n-3 FA: 46.2%; total n-6 FA: 21.5%), whereas the SUM forage FA included CON (total n-3 FA: 44.4%; total n-6 FA: 22.6%) and TRT (total n-3 FA, 45.7%; total n-6 FA, 22.0%). No differences in the milk content of total PUFA, branched-chain FA, or biohydrogenation intermediates (e.g., trans-11 18:1) were observed in either experiment. Milk proportions of total odd-chain FA were higher (P<0.01) in SPR TRT (2.07 g/100 g) than in SPR CON (1.96 g/100 g). Milk proportions of n-3 FA and trans-18:1 were respectively lower (P<0.01) in SPR TRT (0.64 g/100g; 20.5 g/100 g) than in SPR CON (0.71 g/100g; 22.8 g/100 g), but the contents of these FA were not different between groups. Milk content of 12:0 was higher (P < 0.05) in SPR TRT (1.86 g/kg milk) than in SPR CON (1.56 g/kg milk) (P <0.05). Total milk SFA content was higher (P<0.05) in SUM TRT (33.7 g/kg) than in SUM CON (29.1 g/kg). Milk content of de novo FA (CON: 11.6 g/kg milk; TRT: 13.2 g/kg milk) and mixed FA (CON: 13.0 g/kg milk; TRT: 16.2 g/kg milk) were higher (P<0.01) in SUM AFC-fed cows. In conclusion, AFC altered the composition and content of milk FA.

Keywords: dairy, organic, pasture