Evaluation of hematological changes as indicators of liver abscess formation in beef x dairy cross steers

Authors: LAWRENCE, MACY - Texas Tech University; Broadway, Paul; Sanchez, Nicole; LAWRENCE, TY - West Texas A & M University; NAGARAJA, T - Kansas State University; AMACHAWADI, R - Kansas State University; GALYEAN, MICHAEL - Texas Tech University; HALES, KRISTIN - Texas Tech University

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: This study objective was to evaluate physiological and immunological measurements that could be indicative of liver abscesses (LA) in weaned beef × dairy cross steers. For this study, 40 beef × dairy cross steers (initial BW 120 ± 12 kg) were sourced from a local dairy calf ranch and transported approximately 166 km to USDA-ARS Livestock Issues Research Unit’s Liberty Farm in Lubbock, TX (d -16). Calves were initially housed outside in soil-surfaced pens (10 calves/pen) for 16 d; calves had ad libitum access to water and standard high-forage receiving diet before being moved into individual pens within an environmentally controlled barn (d 0). While housed in the barn, calves were cycled between a high-forage diet and a high-concentrate finishing diet for 3 cycles, consisting of 3 days on the high-concentrate diet and 2 days on the high-forage diet. Additionally, calves were administered Fusobacterium necrophorum subsp. necrophorum (100 ml of 4.3 x 106 CFU per ml culture) and Salmonella enterica serotype Lubbock (100 ml of 1.3 x 106 CFU per ml culture) intraruminally on d 0, 5, and 10. Following the last inoculation on d 10, calves were fed the finishing diet for the remainder of the study. Blood samples for complete blood cell counts were collected via jugular venipuncture on d 0, 10, 21 and 30. On d 31, calves were euthanized to evaluate LA prevalence. Fifty percent of calves developed at least one LA. Complete blood count analysis revealed day effects (P = 0.03) for all variables, except for basophil percentage (P = 0.06). Prevalence of a liver abscess affected neutrophil counts, neutrophil: lymphocyte ratio, neutrophil percentage, lymphocyte percentage, and monocyte percentage (P = 0.04). Specifically, neutrophil count, neutrophil percentage, and neutrophil: lymphocyte ratios were greater in calves with an abscess. Likewise, lymphocyte and monocyte percentages were less in calves with at least one LA than calves with no LA. Additionally, a tendency (P = 0.09) was observed for decreased red blood cells in calves with a LA than calves without LA. These data suggest that changes in neutrophil and lymphocyte concentrations within the blood may be indicative of LA prevalence in beef × dairy steer calves and hold potential as predictive markers for LA.