An assessment of behavioural syndromes in rangeland-raised beef cattle

Individuals in most animal groups exhibit consistent behavioural differences across situations or over time known as behavioural syndromes. We conducted a study with a herd of young rangeland-raised cows to determine whether animals exhibited consistent differences in foraging behaviours across contexts (confinement vs. rangeland pasture) and could be clustered into behavioural type groups on the basis of a suite of correlated behaviours. We also investigated whether cows with different behavioural types performed differently in this environment. Supplement consumption rate (SCR) in confinement was used to select two groups of cows (fast eaters vs. slow eaters). This classification was validated by measuring the persistence of SCR differences through time, conducting cluster analysis to classify individuals into two behavioural types (BT1 and BT2) on the basis of a suite of 14 behavioural, physiological, and performance predictors, and comparing serum cortisol concentrations of cows in either group. Discriminant and linear correlation analyses were used to assess the influence of behavioural and performance responses on the classification of cows, and to study the relationships between behaviour and animal performance. Thirty-three young cows were tracked with GPS collars for approximately 45 days during the calving seasons of 2006 and 2007 and several performance responses were measured on each individual. Cows classified as exhibiting BT1 had significantly higher (P ≤ 0.05) SCR (mean ± SE 2006: 1.90 ± 0.1; 2007: 2.54 ± 0.1 g/s) and serum cortisol (SC) concentrations (8.8 ± 0.88 ng/mL) than BT2 counterparts (SCR 2006: 0.32 ± 0.03 g/s; SCR 2007: 1.59 ± 0.1 g/s; SC: 5.5 ± 0.5 ng/mL). Compared to BT2 cows, BT1 individuals tended to spend less time at water (BT1: 73 ± 10; BT2: 172 ± 16 min/day), cover larger areas (BT1: 21 ± 0.3; BT2: 17 ± 2 ha/day), and exhibit less concentrated search patterns (BT1: 264 ± 8.9; BT2: 314 ± 2 6 m travelled/(ha covered/day)). BT1 individuals tended to be heavier (BT1: 434 ± 7; BT2: 394 ± 10 kg) and began gaining weight sooner after calving (BT1: 44 ± 3; BT2: 69 ± 6 days). Cows exhibiting BT1 were more abundant in the herd and appeared to perform better in the rangeland environment where we conducted the study. Further research is needed to determine the constraints imposed by this behavioural syndrome on animal performance in other feeding environments.