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ARS Home » Plains Area » Mandan, North Dakota » Northern Great Plains Research Laboratory » Research » Publications at this Location » Publication #195746
Title: MAMMARY LIPID METABOLISM IN PRIMIPAROUS BEEF COWS FED HIGH-LENOLEATE SAFFLOWER SEEDS

Author
item MURRIETA, C. - UNIVERSITY OF WYOMING
item Scholljegerdes, Eric
item HESS, B. - UNIVERSITY OF WYOMING
item RULE, D. - UNIVERSITY OF WYOMING
item ENGLE, T. - COLORADO STATE UNIVERSITY
item HOSSNER, K. - COLORADO STATE UNIVERSITY

Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 10/20/2005
Publication Date: 12/20/2005
Citation: Murrieta, C.M., Scholljegerdes, E.J., Hess, B.W., Rule, D.D., Engle, T.E., Hossner, K.L. 2005. Mammary lipid metabolism in primiparous beef cows fed high-lenoleate safflower seeds. American Society of Animal Science Annual Meeting, Vol. 83:55.

Interpretive Summary:

Technical Abstract: The objective of this study was to evaluate mammary gland fatty acid metabolism in lactating beef cows fed a high-linoleate supplement. Eighteen primiparous beef cows (BW = 411 ± 24.3 kg.; BCS = 5.25) were fed Foxtail millet hay at 2.13% of BW and either a low-fat control (n = 9) or a cracked high-linoleate (67%, 18:2 n-6) safflower seed supplement (n = 9). Diets were isonitrogenous and isocaloric and the high-linoleate diet contained 5% of DMI as fat. At slaughter (d 37 ± 3 postpartum) mammary and milk samples were immediately frozen in liquid N2 and stored at -80oC. Fatty acid composition of milk fat preparations was determined using GLC. Ribonuclease protection assay was used to quantify mRNA for acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), lipoprotein lipase (LPL) and stearoyl-CoA desaturase (SCD). Weight percentage of milk fatty acids indicative of de novo synthesis (10:0, P < 0.001; 12:0, P < 0.001; 14:0, P = 0.002; 16:0, P = 0.02) were less for cows fed linoleate. Desaturation products 14:1cis9 (P = 0.001), 15:1cis9 (P = 0.002), and 16:1cis9 (P = 0.01) decreased in milk fat of cows fed the linoleate diet; however, weight percentage of 18:1cis9 was greater (P = 0.01) in milk fat of linoleate cows. Biohydrogenation intermediates 18:1trans9 (P = 0.03), 18:1trans10 (P = 0.03), 18:1trans11 (P = 0.01), and 18:2cis9,trans11 (P = 0.02) were greater in milk fat of linoleate compared with control cows. Weight percentage of 18:0 was greater (P = 0.01) in cows fed linoleate than control cows. Dietary treatment did not affect ACC (P = 0.21) or FAS (P = 0.40) mRNA concentrations; however, relative abundance of mRNA for LPL decreased (P = 0.03) whereas SCD mRNA tended to increase (P = 0.11) in the mammary glands of cows fed linoleate. Supplementing diets of lactating beef cows with high-linoleate safflower seeds altered fatty acid composition of milk fat and may affect lipid metabolism at the genetic level of the mammary gland.