03696naa a2200301 a 450000100080000000500110000800800410001902200140006002400270007410000220010124501770012326000090030050008660030952018280117565300190300365300250302265300240304765300210307165300310309270000190312370000140314270000200315670000230317670000210319970000160322070000220323677301360325810635882023-09-25       2023    bl uuuu     u00u1 u    #d  a0931-24397 a10.1111/jpn.137662DOI1 aJORGE-SMEDING, E.  aEnergy, protein and redox metabolism underlying adaptive responses in New Zealand versus North American Holstein cows in pasture-based dairy systems.h[electronic resource]  c2023  aArticle history: Received 22 November 2021; Accepted 10 August 2022; First published online 26 August 2022; Issue online 03 May 2023. --  Corresponding author: Astessiano, A.L.; Departamento de Producción Animal y Pasturas, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay; email:lauaste@gmail.com -- This research was partially funded by the CSIC I+D Research Programme (Udelar) awarded to M. Carriquiry, and by the Agencia Nacional de Investigación e Innovación (Uruguay) through the graduate scholarship awarded to E. Jorge?Smeding (POS_NAC_2017_1_141119). This study was carried out in compliance with the ARRIVE guidelines, and the European Union (EU) standards on the protection of animals used for scientific purposes. All procedures were approved by the Ethics Committee on Animal Experimentation of INIA (form #INIA 2017.2).  aABSTRACT.-  This study explored the metabolic adaptions to grazing conditions of two Holstein genetic strains (GS; North American, NAH; New Zealand, NZH) in two feeding strategies (FS; restricted, P30, vs. maximised, PMAX, grazing). Four groups (NAH-P30, NZH-P30, NAH-PMAX and NZH-PMAX; n = 10 cows each) were compared between ?45 and 180 days in milk (DIM). NZH cows had lower (p = 0.02) fat and protein corrected milk (FPCM) yield and a tendency for lower (p = 0.09) body condition score concomitantly with a trend (p < 0.07) for higher average plasma insulin and lower (p = 0.01) 3-methylhistidine (3MH) at ?45 DIM than NAH. Plasma glucose tended to be affected by the triple interaction GS × FS × DIM (p = 0.06) as it was similar between NAH-P30 and NZH-P30, but higher (p ? 0.02) for NZH-PMAX than NAH-PMAX except at 21 DIM. The physiological imbalance index was affected by the GS × FS interaction (p < 0.01) as it was lower (p < 0.01) only for NZH-PMAX versus NAH-PMAX. NZH cows had higher (p = 0.01) plasma thiobarbituric acid reactive substances at ?45 DIM and tended to have higher protein carbonyls (p = 0.10) and superoxide dismutase (SOD) activity (p = 0.06) on average, and had higher (p < 0.01) ?-tocopherol during mid-lactation than NAH Regarding the FS, FPCM was similar (p = 0.12) among them, but PMAX cows had higher (p < 0.01) plasma non-esterified fatty acids and 3MH, and lower insulin (p < 0.01) than P30 at 100 DIM. PMAX cows showed higher average SOD activity (p = 0.01) and plasma ?-tocopherol at 100 and 180 DIM (p < 0.01). Under grazing, NZH cows can have a better energy status and lower muscle mobilisation but a higher redox reactivity. Maximising grazing can worsen energy status and muscle mobilisation while improving antioxidant response with no effect on FPCM. © 2022 Wiley-VCH GmbH.  aGenetic strain  aMetabolic adaptation  aMuscle mobilisation  aOxidative stress  aPasture-based dairy system1 aCARRIQUIRY, M.1 aCASAL, A.1 aARMAND UGON, D.1 aMASTROGIOVANNI, M.1 aTROTSCHANSKY, A.1 aMENDOZA, A.1 aASTESSIANO, A. L.  tJournal of Animal Physiology and Animal Nutrition. 2023, Volume 107, Issue 3, Pages 754-768. doi: https://doi.org/10.1111/jpn.13766