Abstract The objective was to determine the most appropriate measure of variability in dry matter intake (DMI) and the relationship to growth performance in feedlot cattle. Traditional management of feedlot cattle has focused on minimizing variation in DMI to support greater DMI, reduce ruminal acidosis, and improve average daily gain (ADG). However, variation in DMI can be expressed using various mathematical expressions. Simmental × Angus steers (N = 447) were fed in two contemporary groups a common diet consisting of high moisture corn, modified wet distillers grains with solubles, and corn silage. Daily, individual DMI data was measured using Vytelle feed bunks for a minimum of 125 days for both contemporary groups. Variability in dry matter intake was described by the following traits: standard deviation, coefficient of variation, daily fluctuation, variance to mean ratio (VMR), and Euclidean distance. Data were analyzed using partial correlations in the CORR procedure of SAS 9.4 to account for contemporary group. Fluctuation in DMI greater than 30% and coefficient of variation of DMI had the strongest negative relationship (r -0.26; P ≤ 0.01) to ADG during the feedlot phase. Euclidean distance, standard deviation, and VMR were not related (P ≥ 0.25) to overall ADG. Dry matter intake CV had the strongest relationship (r = -0.28; P ≤ 0.01) to final body weight, but all other correlation coefficients were less than -0.2. The strong relationships (r -0.45; P ≤ 0.01) with DMI were observed for fluctuation in DMI greater than 30% and DMI CV. Dry matter intake as a percentage of body weight was most strongly correlated with fluctuation in DMI greater than 30% (r -0.40; P ≤ 0.01). Gain:Feed was not strongly related to measures of variation in DMI with correlation coefficients less than 0.20. In conclusion, results demonstrate that fluctuation in DMI greater than 30% and CV of DMI are the most useful measures of variability in DMI based on their relationship to feed intake and growth performance.
Evans et al. (Wed,) studied this question.