Severity of liver abscesses and efficiency of feed utilization of feedlot cattle

Relationships of gain, intake, feed efficiency and severity of liver abscesses were evaluated in 12 experiments involving 566 head of individually fed cattle. Concentrate level in the diets ranged from 64 to 95%. In all experiments, livers were scored as unabscessed (0), one or two small abscesses (A-), two to four small active abscesses (A) or one or more large, active abscesses (A+). Based on homogeneity of variances, nine of the experiments were divided into two groups. In one group (four experiments) the incidence of liver abscesses was 32.1% and no significant (P greater than .25) effects of liver abscess severity score on feedlot performance variables were found. In the second group (five experiments), the incidence of liver abscesses was 77.7%. In the second group, liver abscess severity score affected final live weight (P less than .10), hot carcass weight (P less than .0001), dry matter intake (P less than .10), daily gain based on live weight recorded 24 h prior to slaughter (P less than .10), daily gain based on live weight estimated from hot carcass weight with a 62% dressing percentage (P less than .0001), feed efficiency using final live weight estimated from hot carcass weight (P less than .0001) and dressing percentage (P less than .01). In all cases, performance means for cattle with A+ liver scores were the only ones that differed significantly from those of non-abscessed cattle.