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In the present study, the effects of feeding 450 g/day of rumen-protected fish oil (FO) compared to sunflower oil (SO) to Angus heifers (60 g/kg total intake) were quantified. Animal performance was not affected whereas the physico-chemical meat quality, assessed in three muscles, was slightly affected by diet. The oxidative shelf life of the perirenal fat declined with FO compared to SO. Despite the formerly shown increased n –3 fatty acid proportions of meat due to FO supplementation, a trained sensory panel identified an only slightly more intense fishy flavour in grilled steaks and beef patties from the FO compared to the SO group. In FO compared to SO patties, flavour intensity was more pronounced. The perception of off-flavours was negligible and differences between muscles were larger than between diets. In conclusion, supplementing ruminants with FO containing nutritionally beneficial n –3 fatty acids results in few side-effects on meat quality, restricted to quite faint off-flavours and a shorter fat shelf life. • Exchange of rumen-protected sunflower oil for fish oil was tested in beef heifers. • Effects on performance and physico-chemical quality of the beef were small. • The use of fish oil reduced the oxidative stability of the body fat by one third. • Grilled steaks and beef patties were perceived slightly more fishy with fish oil. • Sensory attributes differed more between muscles than between oil types. [ABSTRACT FROM AUTHOR]

The study used 81 young bulls, half of which were disbudded at 7 weeks of age. The effects of horn status during rearing and of acute physical and emotional stress just before slaughter on the physiological status at slaughter and subsequent meat quality were investigated. Bulls were reared in groups containing i) only bulls with horns, ii) only bulls without horns, or iii) mixed (half with, and half without horns). Bulls of each rearing condition were assigned to one of two slaughter conditions: with limited (LS) or with supplementary stress (SS). LS resulted in lower heart rates, stress hormone concentrations and carcass temperature, whereas SS resulted in faster post mortem pH decline and lower juiciness. Horned bulls from unmixed rearing groups had lower early pm temperature, shorter sarcomeres, and lower tenderness compared to disbudded bulls. Correlations and regression analysis revealed relationships between physiological indicators, mainly heart rate before slaughter, and meat quality, including water-holding capacity and indicators of proteolysis. • Pre-slaughter animal stress reduced beef juiciness. • Relationships between pre-slaughter physiological status and meat quality • In homogenous rearing groups: tougher meat in horned than disbudded bulls • Bulls of mixed rearing groups: less reactive to pre-slaughter stress [ABSTRACT FROM AUTHOR]