Relationships between bunk attendance, intake and performance of steers and heifers on varying feeding regimes

Abstract

Six crossbred heifers (average weight 481±22 kg) and six crossbred steers (average weight 471±44 kg) were penned individually in pens 2 m×5 m in size. Feeding behaviours during ad libitum (Day 0–28) and restricted intake (95% of ad libitum; Day 29–54) were derived from bunk attendance recordings made using radio frequency technology (GrowSafe Systems Ltd.). Dry matter intake (DMI), average daily gain (ADG), feed efficiency and eating rate were recorded during the 54-day trial period. Feed was delivered at 08:30 and 13:30 h daily. Eating rate was estimated by recording the amount of feed remaining 3 h after each feeding (i.e. at 11:30 and 16:00 h daily). Positive relationships were observed between average daily duration of bunk attendance and average DMI, and between average duration of attendance and ADG. Cattle spending more time at the bunk consumed more and gained more quickly. Feed efficiency was negatively correlated to time at the bunk ( r=−0.17; P<0.0001). Frequency of bunk visits was not related to feed intake ( r=0.09; P>0.10). Correlations between bunk attendance duration and average daily intake (kg per day) were ( r=0.38; P<0.001) and bunk attendance duration and ADG were ( r=0.14; P<0.001). The relationship between feeding duration and performance may be slightly stronger than was previously believed. Bunk visits were more frequent and of longer duration, and DMI was higher ( P<0.0001) when cattle were fed to ad libitum intake than when limit-fed. Heifers had higher ( P<0.0001) bunk attendance duration, visit frequency, DMI and ADG than steers. Passive radio transponder technology is an excellent tool for documenting the feeding behaviour and such behaviour may be related to animal performance.