The goals of this study were to evaluate the length of time grazing which should be monitored over a 24-h period to predict the grazing behavior of beef heifers within a season and determine the patterns of foraging activity over 24 h. A database was constructed between 2010 and 2012 for beef heifers managed under rotational grazing in a natural grassland. Grazing, rumination, and other activity times were assessed visually during 24 h on 15 occasions. Data were classified according to climatic seasons, generating 12 replicates in summer, 18 in spring, 24 in autumn, and 36 in winter. Treatments were the evaluation of four distinct periods: from sunrise to sunset (DAY-SUN), daylight duration from dawn to nightfall (DAYLIGHT), DAYLIGHT plus 2 h (DAYLIGHT+2), DAYLIGHT to midnight (DAYLIGHT to 0), and the entire 24 h period (CONTROL). Differences for grazing, rumination, and other activities were found in all seasons for the evaluation periods. Sampling sufficiency was reached only with the DAYLIGHT to 0 and CONTROL for all four climatic seasons. The DAYLIGHT to 0 treatment covered 75% of a 24-h period and 95% of the mean foraging time took place during this time interval. Considering grazing distribution during a day, in the warm seasons, the major grazing period during mornings occurred earlier than in the cool seasons, and in cool seasons, the grazing peak was observed during the afternoon. Visual observations from dawn until midnight represented the total grazing time and natural behavior of heifers and could be used to represent grazing activities for the entire day.

这项研究的目的是评估放牧的时间长度，应在24小时内进行监测，以预测一个季节内牛肉小母牛的放牧行为，并确定24小时内觅食活动的方式。在2010年至2012年之间，建立了一个在天然草原上轮牧放牧管理的小母牛牛的数据库。15次在24小时内目视评估放牧，反刍和其他活动时间。根据气候季节对数据进行分类，夏季生成12个副本，春季生成18个副本，秋季生成24个副本，冬季生成36个副本。处理方法是评估四个不同的时期：从日出到日落（DAY-SUN），从黎明到黄昏的白天持续时间（DAYLIGHT），DAYLIGHT加2小时（DAYLIGHT + 2），DAYLIGHT到午夜（DAYLIGHT到0），以及整个24小时内（控制）。在评估期间的所有季节中，发现了放牧，反刍和其他活动的差异。只有在所有四个气候季节的DAYLIGHT均为0且CONTROL时才达到采样充足。从DAYLIGHT到0的处理涵盖了24小时内的75％，在此时间间隔内发生了平均觅食时间的95％。考虑到一天中的放牧分布，在温暖的季节，早晨的主要放牧期发生在凉爽的季节之前，而在凉爽的季节，在下午观察到放牧高峰。从黎明到午夜的目视观察代表了小母牛的总放牧时间和自然行为，可以用来代表一整天的放牧活动。只有在所有四个气候季节的DAYLIGHT均为0且CONTROL时才达到采样充足。从DAYLIGHT到0的处理涵盖了24小时的75％，并且在此时间间隔内发生了平均觅食时间的95％。考虑到一天中的放牧分布，在温暖的季节，早晨的主要放牧期发生在凉爽的季节之前，而在凉爽的季节，在下午观察到放牧高峰。从黎明到午夜的目视观察代表了小母牛的总放牧时间和自然行为，可以用来代表一整天的放牧活动。只有在所有四个气候季节的DAYLIGHT均为0且CONTROL时才达到采样充足。从DAYLIGHT到0的处理涵盖了24小时内的75％，在此时间间隔内发生了平均觅食时间的95％。考虑到一天中的放牧分布，在温暖的季节，早晨的主要放牧期发生在凉爽的季节之前，而在凉爽的季节，在下午观察到放牧高峰。从黎明到午夜的目视观察代表了小母牛的总放牧时间和自然行为，可以用来代表一整天的放牧活动。考虑到一天中的放牧分布，在温暖的季节，早晨的主要放牧期发生在凉爽的季节之前，而在凉爽的季节，在下午观察到放牧高峰。从黎明到午夜的目视观察代表了小母牛的总放牧时间和自然行为，可以用来代表一整天的放牧活动。考虑到一天中的放牧分布，在温暖的季节，早晨的主要放牧期发生在凉爽的季节之前，而在凉爽的季节，在下午观察到放牧高峰。从黎明到午夜的目视观察代表了小母牛的总放牧时间和自然行为，可以用来代表一整天的放牧活动。