The objective of the study was to validate a halter and pedometer for monitoring feeding and locomotive behaviors. The study was conducted at the University of Minnesota grazing dairy in Morris, Minnesota, from May to June 2018. Lactating crossbred dairy cows (n = 12) were offered pasture for 22 h per day during the study. The RumiWatchSystem (Rumiwatch, Itin and Hoch GmbH, Liestal, Switzerland) classified data with a halter as ruminating, eating, drinking and other, and classified data with a pedometer as standing, lying and walking behaviors. In addition, the halter classified jaw movements as grazing bites or rumination chews. Observational data were recorded on Samsung tablets using the Pocket observer app (The Observer XT, Version 14.0, Noldus Information Technology, Leesburg, VA). Agreement was determined between visual observation and the halter and pedometer for 144 h of feeding and locomotive behaviors. Additionally, grazing bites and rumination chews during 1,205 min were evaluated between direct visual observation and the halter. Pearson correlations and concordance correlation coefficient (PROC CORR of SAS), bias correction factors (Cb), location shift (V) and scale shift (µ) (epiR package of R software) evaluated associations between direct visual observations and the halter and pedometer. Correlations between visual observations and the halter (P < 0.01) were 0.84 for ruminating, 0.76 for eating, 0.39 for drinking, and 0.57 for other behaviors. Correlations between visual observations and the pedometer (P < 0.01) were 0.83 for standing, 0.91 for lying, and 0.38 for walking behaviors. The correlations for grazing bites and rumination chews were 0.46 (P < 0.01) and −0.04 (P = 0.79), respectively. For grazing bites and rumination chews analyzed together, the correlation was 0.68 (P < 0.01). The results suggest that the RumiWatchSystem may accurately monitor rumination and eating, as well as standing and lying behaviors in a grazing system. Behaviors such as drinking and walking were seldom observed and may be difficult to accurately monitor in grazing dairy cattle.