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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #352843

Title: Impacts of seasonal variation and winter supplementation of ground whole flaxseed on milk fatty acid composition of organic dairy cows in the northeastern United States

item HAFLA, AIMEE - Agri Food - Canada
item Soder, Kathy
item BRITO, ANDRE - University Of New Hampshire
item KERSBERGEN, RICHARD - University Of Maine
item BENSON, FAY - Cornell University
item DARBY, HEATHER - University Of Vermont
item RUBANO, MELISSA - Consultant
item DILLARD, LEANNE - University Of Auburn
item KRAFT, JANA - University Of Vermont
item REIS, SIMONE - University Of New Hampshire

Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2018
Publication Date: 9/26/2018
Citation: Hafla, A., Soder, K.J., Brito, A., Kersbergen, R., Benson, F., Darby, H., Rubano, M., Dillard, L., Kraft, J., Reis, S. 2018. Impacts of seasonal variation and winter supplementation of ground whole flaxseed on milk fatty acid composition of organic dairy cows in the northeastern United States. Professional Animal Scientist. 34:397-409.

Interpretive Summary: Dairy cows grazing pasture have altered milk fatty acid profiles that may have human health benefits. However, these beneficial milk fatty acid profiles are not maintained during the wintertime when hay and silage are fed. We evaluated the effect of feeding flaxseed to organic dairy cows fed hay and silage during the wintertime on milk fatty acid profiles. Levels of flaxseed supplementation needed to improve milk fatty acid profiles may also decrease milk production. Increased milk price would be necessary to compensate farmers for increased feed costs and reduced milk production associated with flaxseed supplementation.

Technical Abstract: Fourteen organic dairy farms in the northeastern United States were used to evaluate: 1) seasonal variation in bioactive milk fatty acid (FA) profile from 2012 to 2015; and 2) supplementation of ground whole flaxseed (GFLX) to maintain elevated concentrations of bioactive milk FA during the non-grazing season. During regular farm visits, milk, feed, and pasture samples were collected, and diet composition, milk yield, and milk composition recorded. During winters of 2013-14 and 2014-15, 9 farms supplemented GFLX at 6% of diet dry matter to half of each herd (n = 238 cows/treatment). Milk samples were collected and pooled by treatment (GFLX or control). Data were analyzed using the MIXED procedure of SAS. A significant month × year interaction (P < 0.05) for omega-3 (n-3) FA showed an increase beginning in April of 2014 through the end of the study. The proportion of conjugated linoleic acid (CLA) showed a seasonal pattern with greatest (P < 0.05) concentrations (1.32% of total milk FA) during the grazing season. Winter flaxseed supplementation did not impact (P > 0.15) milk yield, concentrations of milk fat and protein, or body condition score. Compared with the control diet, GFLX decreased (P < 0.05) total milk saturated FA by 3.1% percentage units, increased (P < 0.05) n-3 by 88%, and tended (P = 0.13) to increase total CLA proportion by 9%. While GFLX supplementation increased milk n-3, lesser impacts on saturated FA and total CLA proportions indicated that a greater level of winter supplementation is required to improve milk FA profile during the non-grazing season.