Flight speed as predictor of cattle ability to adapt to feedlots

Abstract Text: The aim of this study was to assess the efficacy of flight speed (FS) as a predictor of cattle ability to adapt to feedlots. Ninety-four animals were studied at the Instituto de Zootecnia; research farm in Sertãozinho-SP, Brazil. Cattle from three herds; 28 Nellore from a Control herd (not genetically selected for  maximum post-weaning weights), 26 Nellore from a Selection herd and 40 Guzerat (animals of both herds were selected based on a maximum differential in yearling weight) were assessed over a 173 d study. Cattle were housed according to their breed (Nellore and Guzerat) in two feedlot pens (68.59 and 105.60 m²/animal, respectively). Flight speed (FS, m/s) was assessed 1 d after obtaining initial body weight. ADG (kg/d) and bunk attendance (BA, min/d) were used as confirmatory indicators of cattle adaptation to feedlot. ADG was calculated for the entire feeding period (ADGtot; d 1 to d 169), and also for three feeding phases, defined as initial (ADGin, from d 1 to d 56), intermediate (ADGit, from d 57 to d 113) and the final (ADGfi, from d 114 to d 169). BA was recorded on days 5, 13, 21, 35, 42, 50, 171, 172 and 173 of the study from 0700 to 1200 h by direct observation using a 10 min interval scan sampling technique. BA was also calculated for the entire feeding period (BAtot, from d 5 to d 173) and for three feeding phases defined as initial (BAin, from d 5 to d 21), intermediate (BAit, d 35 to  d 50) and final (BAfin, d 171 to d 173). Regression analysis was used to assess the effect of FS on ADG and BA for the entire feeding period as well as each feeding phase using a model that included the fixed effects of herd and FS as a covariate (linear effect). Flight speed had significant effects on ADGit (ADGit= 0.78 - 0.025*FS; R²= 0.31; P<0.05), ADGfin (ADGfi= 0.80 - 0.016*FS; R²= 0.34; P=0.08) and ADGtot (ADGtot= 0.72 - 0.015*FS; R²= 0.41; P<0.05). No relationship (P>0.05) was observed between FS and BA. The results of this study indicate that FS (assessed within the first d of arrival to the feedlot) has potential to be used as an indicator of cattle ability to adapt to the feedlot, however further studies are needed for a more thorough understanding of this relationship.

Keywords: adaptability, confinement, temperament