Shahid Bahonar University of Kerman and Iranian Society of Animal Science Journal of Livestock Science and Technologies 2322-3553 15 1 2027 07 01 Effects of emulsified oil and lysophospholipid on performance, milk fatty acid profile, and blood parameters in early-lactating Holstein cows under heat stress 37 46 5351 10.22103/jlst.2026.26363.1701 EN Radman Bakhtiari Department of Animal Nutrition, Faculty of Animal Sciences and Fisheries, Sari University of Agricultural Sciences and Natural Resources, Sari, Iran Yadollah Chashnidel Department of Animal Nutrition, Faculty of Animal Sciences and Fisheries, Sari University of Agricultural Sciences and Natural Resources, Sari, Iran Asdollah Teymouri Yanesari Department of Animal Nutrition, Faculty of Animal Sciences and Fisheries, Sari University of Agricultural Sciences and Natural Resources, Sari, Iran Ali-Reza Bayat Animal Nutrition, Production Systems, Natural Resources Institute Finland (Luke), FI-31600 Jokioinen, Finland Journal Article 2025 11 22 This study evaluated the effects of emulsified oil (EO) and lysophospholipid (LPL) supplementation on early-lactating Holstein cows under heat stress. Fifteen multiparous Holstein cows were assigned to a completely randomized design for 70 days with three dietary treatments: 1) a basal diet containing (dry matter basis; DM) 1.52% pure fat powder (PFP; control); 2) the basal diet supplemented with 0.15% LPL (partially replacing PFP); and 3) the basal diet supplemented with 1.52% EO (completely replacing 1.52% PFP). Dry matter intake and milk yield were recorded daily. Milk and blood samples were collected at the end of the experiment. The average temperature-humidity index (THI) during the study was 71. Dietary treatments did not significantly affect DM intake or average milk yield (<em>P</em>>0.05). Milk fat yield was significantly greater in the EO group compared with the LPL and PFP groups (<em>P</em><0.05). Supplementation with EO increased milk yield during weeks 2, 3, and 6 relative to PFP (<em>P</em><0.05). Cows receiving EO exhibited lower proportions of C16:0 and higher proportions of C18:1, C18:2, and C18:3 fatty acids (<em>P</em><0.05). Plasma glucose concentrations were elevated in cows fed EO compared with the other treatments (<em>P</em><0.05), whereas cholesterol concentrations were reduced by both EO and LPL compared with PFP (<em>P</em><0.05). Emulsified oil supplementation significantly decreased plasma low-density lipoprotein (LDL), β-hydroxybutyric acid (BHBA), and non-esterified fatty acids (NEFA) levels relative to PFP (<em>P</em><0.05), while plasma albumin concentrations were higher in the LPL and PFP groups than in EO (<em>P</em><0.05). In addition, EO supplementation significantly reduced plasma creatine phosphokinase activity compared with PFP (<em>P</em><0.05). Overall, EO supplementation enhanced milk fat yield, improved milk unsaturated fatty acid profile, and optimized blood metabolites, indicating its potential to support metabolic efficiency and lactational performance in early-lactating Holstein cows under heat stress condition. https://lst.uk.ac.ir/article_5351_9059fb421cd980f0f97fd3d594840608.pdf