Feeding behaviour of beef cattle in intensive finishing on pasture and supplemented with different additives.

Context: Concentrate supplementation at high rates represents a method used to improve the productive efficiency of the beef cattle grazing system. Further, the use of additives increases the nutrient-use efficiency of diets. In this sense, it is important to determine the impact of additives in grazing beef cattle fed with high-concentrate supplements to determine the appropriate management practices of the system. Aim: This study aimed to evaluate the feeding behaviour of Nellore beef cattle (Bos taurus indicus) in intensive finishing on pasture and fed with different additives. Methods: Twenty-eight Nellore cattle [with initial bodyweight (BW) of 480 ± 5 kg and age of 24 ± 2 months] were finished on Urochloa brizantha cv. BRS Piatã pastures. The animals were assigned to a completely randomised design with four experimental supplements: U (urea as non-protein nitrogen source), UO (slow-release urea partially replacing urea), UOL (supplement UO + Saccharomyces cerevisiae yeast), and UOLP (supplement UOL + multi-strain probiotics). Key results: Supplement intake and idleness time were most affected by the season (P < 0.001). The total dry-matter intake was higher in UOLP (P < 0.004), and this supplement also produced the least effects on feeding behaviour. Conclusion: The beginning of the rains affected the feeding behaviour. The additive combination in intensive finishing on pasture, such as UOL and UOLP, improved the intake and did not affect the feeding behaviour during the day. Implications: These results indicate that the use of additives in intensive finishing on pasture improves productive efficiency and does not change the animal's behaviour, resulting in an important technology to be disseminated and applied by grazing beef cattle producers. High-concentrate supplementation and additives are used to improve the productive efficiency of beef cattle grazing system. In this sense, it is important to determine the effects of additives in supplements for beef cattle in intensive finishing on pasture to determine appropriate management practices. In this trial, the additives can promote changes on intake and affect the feeding behaviour of grazing beef cattle. This knowledge allows us to make decisions about strategies to improve the productive efficiency in an intensive system. [ABSTRACT FROM AUTHOR]