03652naa a2200349 a 450000100080000000500110000800800410001902400340006010000190009424501390011326000090025250000560026152026340031765000170295165000130296865000120298165300210299365300210301465300130303565300220304865300220307065300120309270000180310470000170312270000200313970000140315970000170317370000180319070000170320870000140322577300630323910575632017-09-18       2017    bl uuuu     u00u1 u    #d7 a10.2527/asasann.2017.3652DOI1 aFERRINHO, A.M.  aEffect of growth rate on beef fatty acid profile from Hereford steers finished either on pasture or in feedlot.h[electronic resource]  c2017  aArticle history: Published online: August 10, 2017.  aAbstract: Different nutritional management during the rearing and finishing periods can determine changes on beef fatty acid profile. Beef lipid composition was quantified in 224 male Hereford calves weaned at 8 wk of age with an average initial live weight (LW) of 170 ± 17 kg. After weaning, 4 nutritional treatments were imposed to obtain different daily LW gains (LWG; kg/d) during the first winter. Nutritional management groups were high LWG in feedlot (HF), low LWG in feedlot (LF), high LWG in pasture (HP), and low LWG in pasture (LP). The finishing phase began when each group reached a mean LW of 350 ± 28 kg. During the finishing phase, one-half of the HF, LF, HP and LP animals were finished on pasture and the other half in a feedlot. The animals were slaughtered when calves in each treatment attained a mean LW of 500 kg. Analysis of beef fatty acids was performed by extraction and methylation from LM, and the fatty acids were quantified using a gas chromatography. The statistical model included the groups at growing phase (HF, LF, HP, and LP) and the groups at finishing phase (feedlot or pasture) and the interaction between growing and finishing phase as fixed effects and LW at the beginning of the finishing phase as a covariable. Tukey?s test was applied to compare the means (P < 0.05). There was interaction between the growing and finishing phases for myristic acid and CLA cis 9, trans 11. Animals from HF finished on pasture presented the highest concentration of myristic acid (2.54%) when compared with the other treatments. The LP and HP groups finished on pasture had more CLA cis 9, trans 11 in their beef composition (0.60 and 0.58%, respectively), whereas animals finished in the feedlot presented the lowest concentrations (average of 0.28%). Finishing phase affected the fatty acid profile (P < 0.05). Higher concentrations of palmitic, oleic, and linoleic acids were observed in beef from animals finished in the feedlot than in beef from those finished on pasture. However, the beef from animals finished on pasture presented high concentrations of stearic, docosapentaenoic, and docosaexaenoic acids. Animals finished on pasture had higher concentrations of linolenic, arachidonic, and eicosapentaenoic acids compared with those finished in feedlot. Interestingly, the LP group presented higher concentrations of linolenic and eicosapentaenoic acids, regardless of the finishing phase. The same results were observed in the LF group for arachidonic acid. In general, the LP and HP groups finished on pasture resulted in healthy beefs, with the greatest CLA and omega-3 concentrations.  aCARNE VACUNA  aNOVILLOS  aURUGUAY  aENGORDE A CORRAL  aFINISHING SYSTEM  aGROW-OUT  aLIPID COMPOSITION  aNOVILLOS HEREFORD  aPASTURA1 aPERIPOLLI, E.1 aBANCHERO, G.1 aPEREIRA, A.S.C.1 aBRITO, G.1 aLA MANNA, A.1 aFERNANDEZ, E.1 aMONTOSSI, F.1 aBALDI, F.  tJournal of Animal Science, 2017gv.95, suppl.4. p.180-181.