Ninety Angus × Hereford steers (259.9 ± 36.18 kg body weight (BW)), were used in a 56-d experiment to assess the effects of flavoring additives on feed intake, and stress and immune response of newly received feedlot cattle. Steers were homogenously distributed by BW into six pens equipped with an individual feed intake monitoring system, and pen was randomly assigned to one of three treatments (15 head/pen; 30 head/treatment): a standard feedlot receiving diet (CT), or the same diet with a flavoring additive comprised of either sweeteners (Luctarom Feedlot, SW) or a mix of basic tastes (Luctarom Feedlot Mix, MX) at 1 kg/mT. Pens were equipped with a feed intake monitoring system, while BW, chute behavior, flight speed, blood and saliva samples were collected bi-weekly, and hair samples collected at 4-week intervals during the study. Data were analyzed using a mixed-effects model for a pen study using individual animal records with repeated measures. There was a treatment × week interaction (P < 0.01) where meal duration was greater in SW steers than MX and CT on wk 3, and than CT on wk 7 and 8. A trend for treatment × week interaction (P = 0.06) showed that the number of visits per day tended to be greater in SW than MX steers on wk 4 and 5, and it tended to be greater in SW than MX and CT on wk 5. The concentration of IL-6 was greater (P <0.01) on d 1 and 28 than on d 14. The IgM concentration was greater (P < 0.01) on d 1 compared to d 14, 28 and 56. The concentration of haptoglobin was greater (P < 0.01) on 14 than d 28, 42 and 56, and it was greater (P < 0.01) on d 1 than d 42 and 56. The concentration of serum amyloid A was greater (P < 0.01) on d 1 compared to the rest of sampling days. Fibrinogen concentration was greater (P < 0.01) on d 1 compared to d 14 and 42. The neutrophil-to-lymphocyte ratio was greater (P < 0.01) on d 42 and 56 compared to d 1 and 28, and greater (P < 0.01) on d 14 compared to d 28. Hair and saliva cortisol concentration were lower (P < 0.01) on d 56 compared to d 1 and 28, respectively. The use of flavoring additives, particularly when based on sweeteners (SW), caused some changes in the feeding pattern of newly received steers. These changes, however, were not consistent over the 56-d feeding period and were not accompanied by a change in growth performance, temperament, biomarkers of stress, inflammation, or immune function.
Keywords: Sensory additives; receiving calves; sweetener.
© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society of Animal Science.