The objective was to determine the effects of liver abscesses on complete blood counts (CBC) and liver function and to identify blood-based biomarkers for detection of liver abscesses in feedlot cattle. Blood samples were collected on a subset of beef × dairy crossbred heifers with and without liver abscesses (n = 94; n = 113, respectively). From these blood samples, CBC and serum chemistry analytes related to liver health (alkaline phosphatase, gamma glutamyl transferase, bile acids, total bilirubin, and cholesterol) were analyzed to characterize animal health and model for liver abscesses. Abscess presence was predicted using logistic regression models and machine learning algorithms, with individual heifer serving as the experimental unit. In a binary system (abscessed or not), heifers with liver abscesses had lower concentrations of lymphocyte (LYM) and total white blood cell (WBC) concentrations but elevated platelet-to-LYM ratio. Serum chemistry measures were not affected by abscess presence or liver score (severity). In univariate, predictive modeling of CBC measures, only total WBC concentration was accurate (65.85%) at predicting liver abscess presence; however, this was not deemed an acceptable biomarker due to its poor specificity (54.79%). Using total WBC, basophils, red blood cells, and procalcitonin as variables to predict liver abscess condition, the Logit- Boost model produced the greatest accuracy (80.65%) and specificity (85.71%). An accurate blood test that allows for the detection of liver abscesses during the finishing phase may allow for therapeutic management or alternative marketing of cattle; however, the marginal accuracy demonstrated in this study combined with the impracticality and cost of analyzing a blood sample may not be feasible. Regardless, the most explanatory CBC variables in cattle with abscessed livers were suggestive of an immune response. Liver condition influenced the CBC of beef × dairy heifers but not serum chemistry. Multivariate predictive models showed potential for predicting liver abscess condition based on CBC. The results of this study warrant further investigation for biomarkers of the liver abscess condition. An antemortem indicator for liver abscesses could prove useful for making management decisions and in research applications, particularly in evaluating interventions.

This study evaluated different strategies of forage inclusion in finishing beef cattle diets and their ef- fects on feed intake, ruminal fermentation and microbiota, blood serum parameters, growth performance, carcass quality, and liver abscesses. Steers (n = 360, 400 ± 29 kg) were stratified by weight and randomly allocated across 24 pens, which were randomly assigned to 1 of 4 dietary treatments (15 steers/pen, 6 pens/treatment) in a completely randomized experiment. Treatments included: (1) positive control (+CTRL) fed a diet (7.5% forage on a diet DM basis) with tylosin (11 mg/kg); (2) negative control (−CTRL; control diet without tylosin); (3) a diet where forage concentration decreased (DECR) every 42 d and was static for the last 84 d (forage represented 15%, 9%, 3%, and 3% of DM, respectively) without tylosin; and (4) a diet where forage concentration increased (INCR), inverse of the DECR without tylosin. The +CTRL steers had greater ADG (1.74 kg/d vs. 1.63 kg/d), shrunk total BW gain (306 vs. 287 kg), and a tendency for greater final BW (705 vs. 687 kg), than than INCR steers. As expected, a diet × period interaction was observed for DMI, but it did not differ among treatments over the full study. Yield scores and rib fat thickness were greater in –CTRL than INCR steers. The percentage of steers with minor liver abscesses tended to be less for +CTRL (51.8%) and DECR (51.8%) compared with −CTRL (62.2%) and INCR (64.3%). Greater dietary con- centrations of forage earlier in the finishing phase, with a subsequent decline thereafter, has the potential to de- crease the proportion of minor liver abscesses similar to typical finishing diets including tylosin, without affecting growth performance or carcass quality.

Beef calf management strategies used during the weaning and postweaning period can have extended effects on growth performance and health in the production chain. With the number of different practices beef cow-calf operators can use during these stages of production, it is important for Extension educators to understand which management strategies are most commonly used and where educational gaps might exist. The objective of this study was to determine farmer perceptions, on-farm applications, and potential barriers to adopting beef calf weaning and backgrounding strategies among Alabama producers. An online survey with 24 total questions was developed and distributed to cattle producers in the state of Alabama in March 2022. Questions addressed whether producers use managed weaning and backgrounding strategies, and respondents followed a predetermined question track based on this response. A total of 214 complete responses were received with 94% of respondents considering their operation to be a cow-calf operation. Most participants (46%) had a herd size of 50 cows or less. Abrupt weaning was the most widely used method of weaning (55%) among producers. Over half (61%) of producers indicated they background their calves, and another 25% stated that they do in some years but not always. For respondents that do not background their calves, market unpredictability is the main driver surrounding the decision to keep calves for backgrounding or to sell immediately after weaning. Key challenges producers who practice managed weaning and backgrounding strategies face in their operations include input costs, land availability, and market predictability. Methods for marketing backgrounded calves differed across respondents, with 49% of respondents using local livestock auctions to sell calves. Developing demonstration data models to address cost benefits of weaning and backgrounding may help producers evaluate areas of challenges identified in this survey. Extension educators can apply these data to create resources centered around backgrounding cattle to help improve potential applications of management after weaning.

This study evaluated 2 beef cattle manage- ment strategies, conventional (CONV) or natural (NAT), for 3 BW groups at weaning to evaluate growth perfor- mance during backgrounding and finishing and carcass characteristics. A total of 240 weaned steers, free of preweaning implants, were allocated into heavy (HV) (290 ± 21 kg; mean ± SD), medium (MD) (247 ± 8 kg), or light (LT) (214 ± 15.6 kg) weight groups over 2 yr. Each weight group (n = 80) was randomly allo- cated to 1 of 2 treatments (n = 40): either conventional or natural (n = 4). Conventional treatments used hormonal implants and feed additives, but the natural treatment did not. Following a 41-d receiving phase, HV steers entered direct finishing, MD steers entered a short backgrounding and finishing, and LT steers entered a long backgrounding, grazing, and finishing, all fed to a shrink weight of 620 kg. Steer ADG was 19% and 22% greater for MD- and LT-CONV, respectively, at backgrounding, compared with NAT. The G:F was 20% greater for HV- and MD-CONV at finishing and 25% greater for LT-CONV at backgrounding. The HV-, MD-, and LT-CONV took 50, 71, and 59 fewer days on feed, respectively, to finish, relative to NAT. The rib-eye area were greatest in HV-CONV, and NAT produced greater marbling, QG (AAA), and backfat thickness and had a greater proportion of liver abscesses. Steers managed without performance-enhancing technologies under west- ern Canadian conditions will have lower ADG, G:F, and YG1, but greater days on feed to a target weight, AAA grade, marbling, and backfat thickness, than convention- ally-managed steers.