Estimating optimal observational sampling frequency of behaviors for cattle fed high- and low-forage diets

Abstract

Video recordings of behavioral activities including eating, ruminating, drinking, standing, and lying were monitored to determine the minimum number of sampling days and sampling frequency required to obtain reliable estimates of these behaviors. Eight continental crossbred heifers, individually housed in a tie-stall barn with total mixed ration provided once per day, were divided by BW into two blocks and assigned to each of the two dietary treatments in a crossover design: high-forage diet (HF, forage:concentrate ratio 70:30) and low-forage diet (LF, forage:concentrate ratio 30:70). The cows were monitored continuously using a digital video recording system for 6 d in each of the two periods and a trained observer manually recorded the behavioral activities by minute. Mean time spent performing each behavior for 6 d with instantaneous samples of 1 min was compared with those obtained using fewer sampling days (1, 2, 3, 4, and 5 d) and less frequent scanning (2, 3, 4, 5, 10, 15, 30, and 60 min) using linear regression analysis, and the minimum number of sampling days or frequency was determined. Diet did not affect the accuracy and precision of predicting behavior from video recordings of the cows. When sampling days and scanning intervals were combined, the minimum recommended sampling frequency for accurately estimating a specific set of behaviors of beef heifers in tie stalls was: eating, 2 d with 4-min intervals; ruminating, 3 d with 4-min intervals; drinking, 2 d with 3-min intervals; and standing and lying, 2 d with 15-min intervals. Increasing sampling frequency beyond these minimums further enhanced the accuracy and precision of predictions. The total time of each behavioral activity was different between cows fed HF and LF diets with eating, ruminating, total chewing, and standing of heifers fed the HF diet greater (P < 0.01), but the lying (P < 0.01) and drinking time (P = 0.028) of heifers fed the LF diet greater. Meal patterns were different (P < 0.05) between the treatments except when meal size (kg) was expressed as DM or OM intake. For rumination patterns, the mean or maximum bout length (min/bout) was greater, but the maximum or minimum length of time heifers took to ruminate after eating was lower for the HF diet. From a practical standpoint, it is recommended to use 3 days of observations scanned at an interval of 4 min to reliably estimate the behavior of cows. If the focus is only lying and standing time, then 2 days with 15 min intervals can be used.

Effects of 3-nitrooxypropanol on enteric methane production, rumen fermentation, and feeding behavior in beef cattle fed a high-forage or high-grain diet1

“…The information about how 3-NOP in a diet influences feeding behavior of beef cattle is lacking. The durations of standing and lying of animals were similar to that of cattle in confined conditions (Dong et al, 2018). Meal frequency and duration were slightly greater for animals in the current study compared with other studies (Holtshausen et al, 2011;He et al, 2015;Dong et al, 2018), probably because DMI of animals in the current study was greater.…”

“…The durations of standing and lying of animals were similar to that of cattle in confined conditions (Dong et al, 2018). Meal frequency and duration were slightly greater for animals in the current study compared with other studies (Holtshausen et al, 2011;He et al, 2015;Dong et al, 2018), probably because DMI of animals in the current study was greater. In addition, meal events (e.g., frequency and duration) can differ depending upon the measurement method of determining feeding behavior (e.g., GrowSafe system or video recording) and method of analyzing behavior data (fixed meal criterion or meal criterion analyzed using models; Bailey et al, 2012).…”

“…Feeding behavior data for individual animals were further processed for meal information. The fixed meal criterion of 300 s was used to calculate meal activities (Dong et al, 2018). A meal, therefore, was considered as all feeding events occurring with the interval less than 5 min between feeding events.…”

Invited review: Current perspectives on eating and rumination activity in dairy cows

“…Thus, it might be possible to use the length of this latency period as an indication of risk of acidosis. In a study of nonlactating heifers fed diets of 70:30 or 30:70 F:C ratio (DM basis), a mean latency period of 19.4 min (range: 4.1-44.5) and 26.0 min (6.0-70.6), respectively, was observed (Dong et al, 2018). The mean rumen pH of cows in that study was 6.57 and 6.15, respectively.…”

“…Video recordings are also time consuming because the scanning interval needs to be frequent such that accuracy of the estimates is not compromised (Hämäläinen et al, 2016). Dong et al (2018) recommended a minimum observational frequency of 2 d with 4-min intervals for eating time and 3 d with 4-min intervals for ruminating time. Bhandari et al (2008) reported a correlation coefficient of 0.94 between continuous monitoring and 5-min scan sampling of eating and ruminating behavior when observed over 3 d. Hämäläinen et al (2016) recommended a sampling interval of 4 min for eating activity and 15 min for ruminating.…”