Effects of flavouring additives on feed intake and immune function of newly received feedlot cattle
Ninety Angus × Hereford steers (259.9 ± 36.18 kg BW) were used in a 56-d experiment to assess the effects of flavouring additives on stimulating feed intake and immune function of newly received feedlot cattle. Steers were homogenously distributed by body weight (BW) into six pens (15 head/pen) and pen was randomly assigned to one of three treatments (two pens/treatment): a standard feedlot receiving diet (CT), or the same diet with a flavouring additive comprised of either sweeteners (SW) or a mix of basic tastes (MX) at 1 g/kg (Lucta SA, Barcelona, Spain). Pens were equipped with a feed intake monitoring system (Growsafe Systems, Airdrie, Canada), while BW, chute behaviour, flight speed, blood samples, saliva samples were collected bi-weekly and hair samples were collected at 4-week intervals during the study. Data were analyzed using a mixed-effects model accounting for repeated measures with steers as the experimental unit, except for chute behaviour, where a non-parametric one-way ANOVA was used. There were multiple treatment × time interactions (P < 0.05). Meal size was greater for SW than CT on wk 3 and than MX on wk 4 and 5, and it was greater for MX than CT and SW on wk 3 and 7, respectively. The daily number of visits to the feed bunk was greater for MX than CT on wk 2, for SW than MX on wk 4, and for CT than in MX and SW on wk 4, and wk 7 and 8, respectively. The eating rate was greater for SW than MX and CT on wk 4 and 5, and on wk 4 than MX, respectively. Although the effects on DMI, average daily gain, and feed efficiency (FE; kg BW/kg DM) were not significant (P > 0.1) over the 56-d feeding period, FE and ADG were greater (P < 0.05) in SW and MX than CT from d 27 to 41, and ADG was lower for SW and MX steers than CT from d 15 to 28. Haptoglobin concentration in blood also showed a treatment × time interaction (P < 0.05), where SW steers had lower concentrations than CT on d 14. Blood fibrinogen and serum amyloid A concentrations were greater (P < 0.01) on d 1 than the rest of the days. Neutrophil percentage was greater (P <0.01) on d 56 than d 28, whereas lymphocyte percentage was lower (P < 0.01) on d 56 than 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 flavouring additives, and mostly the one based on sweeteners, caused some positive changes in the feeding pattern and haptoglobin concentration of newly received steers. These changes, however, were not consistent over the 56-d feeding period and were not accompanied by a change in their growth performance, temperament, or in the biomarkers of stress, inflammation, or immune function. A different combination of flavouring agents, dose, or strategy to use flavouring agents (one flavour profile vs. a rotation of flavours over time) should be explored in future research trials to further assess the efficacy of these additives in newly received feedlot cattle.
Flavouring, Behaviour, Temperament, Growth, Immune
Master of Science (M.Sc.)
Large Animal Clinical Sciences
Large Animal Clinical Sciences