Taste agents as modulators of the feeding behaviour of grazing yaks in alpine meadows

Feeding behaviour plays a significant role in promoting good animal health and welfare. It is also reflec-tive of the quality and quantity of available feed. In fact, grazing livestock do not select their feed ran-domly, rather their behaviour is influenced by the texture, taste, and smell of each pasture species. Although taste agents are often used to modify feed intake for captive livestock, the effect on the feeding behaviour of grazing livestock has not yet been extensively evaluated in native grasslands. To address this gap in knowledge, herein, we sprayed three types of taste agents-salty (SA), sweet (SW), and bitter (BT)-on alpine meadows to investigate their effect on the grazing behaviour of yaks (Bos Grunniens) on the Qinghai-Tibetan Plateau (QTP). Behavioural observations showed that grazing was concentrated primarily in the morning and afternoon, while ruminating/resting peaked at noon; however, the diurnal behavioural patterns of grazing yaks were not affected by the taste agents. Application of the SA agent significantly increased the yaks' grazing time, bites per minute, bites per step, time per feeding station, and steps per feeding station, while significantly reducing walking time, steps per minute, and number of feeding stations per minute. Meanwhile, application of the SW agent significantly increased the yaks' time per feeding station, however, significantly reduced the steps per minute and number of feeding sta-tions per minute. In contrast, the BT agent significantly increased the yaks' walking time, steps per min-ute, and number of feeding stations per minute, while significantly reducing grazing time, bites per minute, bites per step, and time per feeding station. Application of the SA agent also significantly increased the intake of favoured, edible, and inedible forage, while the SW agent improved inedible for-age intake, however, had a more subtle effect on favoured and edible forage intake. Meanwhile, the BT agent had an inhibitory effect on grazing intake. Hence, the structural equation model suggested that taste agents may directly or indirectly influence grazing behaviour by regulating feeding behaviour. Our findings provide a theoretical basis for using taste agents in grasslands to control the grazing beha-viour of livestock and provide a method to promote the stability of grassland communities, while miti-gating the degradation of grasslands in the QTP.CO 2022 The Author(s). Published by Elsevier B.V. on behalf of The Animal Consortium. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Feeding behavior is important for animal health and welfare, and is influenced by the taste of available feed. This study found that spraying taste agents on alpine meadows can directly or indirectly affect the grazing behavior of yaks. These findings provide a theoretical basis for using taste agents to control livestock grazing behavior and mitigate grassland degradation in the Qinghai-Tibetan Plateau.