Studies on the carotenoid content in forage species and tropical beef cattle in Mexico

摘要

Abstract To determine the effect of feed carotenoids on subcutaneous fat colour in cattle, 4567 animals were sampled at an abattoir; 790 of these were chosen for this study on the basis of instrumental colour measurements. The mean concentrations of β-carotene and lutein were 0.23 (SE = 0.008) and 0.12 (SE = 0.004) μgg?1 adipose tissue, respectively. Sun-drying and ensiling resulted in a 97.7% and 67.4% loss of β-carotene respectively (P<0.01), but an average loss of lutein of 71.7% (P<0.1) with no difference (P>0.1) between method of preservation. A 196-day field trial was conducted using 70 cross-bred 320kg (±38 kg) bulls, which were grazed on a 32 ha Brachiaria decumbens pasture and offered a commercial supplement. After 28 days, five animals were also offered sun-dried Brachiaria humidicola, while another five received it ensiled. This scheme was repeated every 28 days, until day 168, when all but 10 animals were being offered either hay or silage. There was no difference in the concentration of eithe...