Effect of concentrate feeder design on feeding behavior in holstein bulls fed high-concentrate diets

Abstract Text:   A total of 240 Holstein bulls (121 ± 2.0 kg BW and 99 ± 1.0 d age), in a replicated factorial study, were randomly allocated in one of 6 pens and assigned to one of the 3 treatments according to the feeder design: conventional feeder with 4 feeding spaces (CF), conventional feeder with less concentrate capacity (CFL), and a single space feeder with lateral protections (SF). Each pen had also 1 straw feeder, and 1 drinker. Each feeder was suspended on 4 load cells that registered continuously contained concentrate weight. Feeding pattern was video-recorded for 24 h on days 7, 119-120, and 215-216 of the study, and was analyzed by continuous scan sampling. Only 12 h (from 6 am to 18 pm) were analyzed as the greatest activity was observed during that time window. Data were analyzed using a mixed-effects model with repeated measures. The percentage of concentrate bunk attendance was greater (P < 0.01) in SF (79.3 ± 0.75%) compared with CF and CFL (70.2 ± 0.75%). The number of visits in SF (44.3 ± 17.36) was lesser (P < 0.05) compared with CF and CFL (118.6 ± 17.36). Obviously, the number of bulls at the SF feeder was (P < 0.01) one and constant throughout the study in contrast with CF and CFL (1.7 ± 0.02), where the number of bulls at the feeder was over 1.5 and decreased with age. No displacements at SF were observed (P < 0.01), whereas in the other feeders some displacements at feeder were registered (CF: 2.3 ± 0.51, CFL: 3.4 ± 0.51 displacements/1 h). The percentage of waiting time at the feeder was greater (P < 0.01) in SF (13.3 ± 2.18%) than in CF and CFL (0.53 ± 2.18%). However, the waiting time at the feeder in SF was reduced (P < 0.05) with age. The eating rate increased (P < 0.05) with age in all treatments, being greater in CF (205.7 ± 7.84 g/min) than CFL (177.4 ± 7.84 g/min) and SF (151.2 ± 7.84 g/min). In conclusion, the design of the SF, one feeding space with lateral barriers, distributes feeder visits throughout the day, decreases displacements at the feeder and decreases eating rate compared with the conventional feeders. The reduction of concentrate capacity at the feeder increases displacements and decreases concentrate eating rate at the feeder.

Keywords: beef, feeder, feeding behavior