Abstract Beef-dairy cross calves have increased prevalence of liver abscesses at slaughter compared to beef calves, which may be due to early feeding management strategies that predispose these animals to gastrointestinal insult during the finishing phase. The objective of this study was to compare different concentrations of starch in calf starter on carryover growth performance and gastrointestinal function in beef-dairy cross calves during finishing transition. During the hutch phase, castrated male beef-dairy cross calves (N = 10) were randomly allocated to one of two calf starters with high (44%) or low (24%) starch (n = 5/treatment) and were fed a common growing diet for 130 days following removal from the hutch. During the finishing transition, all animals (initial BW = 277 kg) received the same diets, which included a starter diet, two step up diets, and a finishing diet, increasing in starch concentration with each diet. Calves were weighed periodically throughout the 28-day finishing period then slaughtered, and pH of rumen, duodenum, jejunum, ileum, and colon contents obtained. Data on BW, DMI, G:F, and pH were analyzed using linear models (R v.4.5.1) with fixed effects (treatment, diet, day, GI segment, and interactions), and random effect of calf when appropriate. ADG (1.68 and 1.92 ± 0.11 kg/d) and G: F (0.247 and 0.286 ± 0.0183 kg/kg) revealed no evidence of difference (P > 0.05) between high and low starch groups, respectively. There was no evidence of difference between treatments on DMI (P = 0.86), although there was a step-up diet effect on DMI where cattle consumed less (P < 0.001) DMI while on step-up diet 2 compared to other diets. The jejunum exhibited a lower pH than the ileum and colon (P < 0.05) for both treatments, while the duodenum was more acidic than the ileum (P < 0.05) for the low starch group only. There were no other significant differences observed between the other sections (P > 0.05). The rumen pH was 6.17 and 6.75 for high and low starch groups, respectively, but there was no evidence of difference between groups (P = 0.34). In conclusion, starch inclusion level of calf starter diet had no carryover effects on feed intake, growth, or gastrointestinal function during the finishing transition.

Heat stress negatively impacts performance and welfare and occurs when total environmental and metabolic thermal load exceeds an animal's ability to dissipate heat. Access to shade has been associated with reductions in body temperature and respiratory rate in cattle, but previous findings on cattle performance has been inconsistent. This pen-level randomized controlled trial evaluated the effects of shade (2.8 m2/head, 100% solar block; n = 12 pens) versus no shade (n = 12 pens) on steer performance following terminal sort at a commercial feedyard in the Pacific Northwest, where animals were housed on roller-compacted concrete floors. Data collected included water consumption, feed delivery, disease events, open mouth breathing (OMB) behavior, and carcass traits. Shade reduced water consumption by 15% (P < 0.05), and pens without shade showed a 6% decrease in feed delivery when the previous day's temperature-humidity index (THI) was ≥ 80 (P < 0.05). Additionally, shade reduced OMB behavior (P = 0.09), the number of culled steers (P < 0.05), and the incidence of dark cutters (P < 0.05). A greater proportion of steers in shaded pens graded choice and prime (93%), compared to those in unshaded pens (91%) (P < 0.05). Inclusion of shade improved animal health, welfare, carcass quality, and environmental stewardship during the summer months in a commercial feedyard setting. Shade should be considered a valuable management tool for mitigating heat stress in finishing cattle.

Summer veterinary research scholars programs (VRSPs) provide valuable hands-on mentored research experience to pre-clinical veterinary students with exposure to various career options. In response to ongoing funding challenges, we aimed to document program impact on participants' careers. We hypothesized that a higher proportion of VRSP participants would pursue a graduate degree, internship, residency, and peer-reviewed publication than non-participants. Veterinarians who graduated in 2000-2024 from Kansas State University, Mississippi State University, the University of Missouri, or the University of Wisconsin completed an online survey. We analyzed quantitative data using logistic regression, including VRSP participation, school, and their interaction as fixed effects. We coded and themed open-ended responses. The study enrolled 1614 alumni (385 VRSP, 1,229 non-VRSP). Participation in VRSPs was associated with increased odds of MS (odds ratio [OR] 3.2, 95% CI = 1.7-5.8, p = .0002), PhD (OR = 9.9, CI = 4.3-22.9, p < .0001), internship (OR = 2.3, CI = 1.7-3.2, p < .0001), residency (OR = 3.7, CI = 2.6-5.3, p < .0001), and peer-review publication (OR = 7.9, CI = 5.7-11.0, p < .0001). The likelihood of pursuing a career in academia (OR = 3.0, CI = 1.8-4.8, p < .0001) was also associated with participation in a VRSP. Qualitative results included five main themes related to how VRSP was significant to participants' careers: Influential, Catalytic, Pivotal, Valuable, and Possible. Early exposure to hands-on mentored research through VRSP successfully impacts alumni careers, contributing to the education and advancement of veterinary researchers. Favorable outcome measures from this study support advocacy to justify renewed federal funding for VRSPs as well as ongoing support from academia and industry.

Non-infectious cardiac failure in feedyard cattle has become more frequently diagnosed. There is limited research assessing gross and histologic lesions in grossly abnormal hearts of harvested cattle. Cases were stratified by heart score (HS) using a scale of 1-5, with 1 representing a normal heart and 5 representing severely remodeled ventricles. Cattle were evaluated for gross lesions of the heart, lung, and liver. Samples collected from each animal for histology included cardiac (n = 4), pulmonary (n = 4), and hepatic (n = 1) tissues. Histologic evaluation scored cardiac and hepatic fibrosis and necrosis, embedded myocardial protozoal cysts (EMPCs) were quantified, and pulmonary lesions were categorized based on histologic patterns. Of 103 cases, 40 had normal HSs (NHSs) (1 or 2), and 63 had abnormal HSs (AHSs) (3, 4, or 5). There were 64 cases with normal lung deflation scores, and 39 cases with abnormal lung deflation scores. At least one cardiac section contained EMPCs in 67 cases. Cattle with abnormal lung deflation scores were more likely to have an AHS (0.76 ± 0.07, p ≤ 0.01) compared with cattle with normal deflation scores (0.52 ± 0.06). Cattle with EMPCs present in at least one cardiac section were more likely to also have an AHS (0.73 ± 0.05, p ≤ 0.1) compared with cattle without EMPCs (0.39 ± 0.08). No histological findings for the lungs or liver were associated with abnormal heart score; however, lung deflation and EMPCs were associated with abnormal heart score.

Cow efficiency is vitally important to beef sustainability, and computer simulation models may be useful tools to identify characteristics of the most efficient cow genotypes for a given production environment. The objective of this analysis was to determine whether the Beef Cattle Systems Model could replicate empirical research demonstrating a genotype-nutritional environment interaction for efficiency of feed conversion to calves weaned. Combinations of cow genotypes for lactation potential (8, 10, and 12 kg/d at peak milk) and growth potential (450, 505, and 650 kg mature weight) were simulated across four dry matter intake levels (58, 76, 93, and 111 g/kg BW0.75). At lower dry matter intakes, cows had lesser body condition scores and weight and longer postpartum intervals, but dry matter intake had minimal influence on pregnancy percentage or calf-weaning weight. These trends match empirical research except for pregnancy percentage, where decreasing dry matter intake had a dramatic effect on pregnancy percentage in high-milking, high-growth-potential genotypes. Efficiency of feed conversion was greatest at low dry matter intake for the model simulation with no evidence of a genotype-dry matter intake interaction, which is in contrast to empirical research demonstrating a genotype-dry matter intake interaction. In conclusion, standard nutrition equations do not replicate the genotype-nutritional environment interaction observed in empirical research studies.

Heat stress occurs when total environmental and metabolic heat production is greater than an animal's ability to dissipate that heat. Heat stress negatively impacts feeder cattle performance and welfare. Limited research has been conducted to determine if feeding cattle in the evening, thereby shifting their metabolic heat production to a cooler period of the day, can help mitigate heat stress. This pen-level randomized controlled trial evaluated the effects of evening feeding (PM; feedings at 2000, 2300, and 0200 h; n = 24 pens) versus morning feeding (AM; feedings at 0500, 0800, and 1200 h; n = 24 pens) on terminally sorted steer performance in a commercial feedyard in the Pacific Northwest. Data collection included feed delivery, water consumption, health events, open mouth breathing prevalence, and carcass traits. Linear and generalized linear mixed-effects models were used to determine potential differences between treatment group and temperature-humidity index (THI; <80 versus ≥80). Only 14% of the total study days had a THI ≥ 80, indicating little to no heat stress impacts. There were no differences found between PM and AM for any outcome (p < 0.05). Regardless of treatment group, water consumption tended (p = 0.07) to increase, and open mouth breathing significantly (p < 0.05) increased on days with THI ≥ 80. Further research is warranted to assess evening feeding as a heat stress mitigation strategy in a feedyard setting.

Inflammatory cytokines and haptoglobin (HPT) were measured from 28 head of cattle that presented with bovine respiratory disease after being purchased and shipped to a common feedlot and assigned to either control or metaphylaxis treatment groups. Blood samples were obtained on the day of purchase (D0) and again at the time of diagnosis (S0) and 5 days after treatment (S5). Plasma was harvested and stored at −80 °C until assayed for the cytokines IFN-γ, IL-1β, IL-6, TNF-α, and HPT. Our objectives in this study were to determine differences between baseline (D0), day of diagnosis (S0) and post-treatment (S5), as well as to identify correlations among cytokine and HPT concentrations over time and by treatment. Interferon-gamma and IL-1β concentrations did not differ between D0 and S0 or S5. Tumor necrosis factor-α concentrations differed between D0 and both S0 and S5; however, no differences were observed between S0 and S5. Interleukin-6 and HPT concentrations differed between D0 and S0, D0 and S5, and between S0 and S5. Neither control nor metaphylactic treatment significantly impacted cytokine or HPT concentrations, nor did the state of origin. The strongest significant correlations among cytokine-timepoint combinations were observed for IL-1β and TNF-α S0 (0.93), and S5 (0.91). Both IL-6 and HPT increased from baseline to the time of BRD diagnosis and treatment, and HPT exhibited the most rapid decline after treatment (S5), suggesting that it may be the most useful single measurement for indicating both sickness and resolution post-treatment.

Acute interstitial pneumonia (AIP) has been a recognized bovine respiratory disease for many decades, yet the sporadic occurrences of AIP in feedlot cattle are poorly understood. We searched 3 databases (PubMed, CABI Direct Library, AGRICOLA) for primary literature on North American feedlot cattle, with a focus on interstitial pneumonia. We comprehensively reviewed reports of clinical signs, pathology findings, etiologies, risk factors, and treatments associated with AIP in feedlot cattle and identified gaps in knowledge. We included 19 peer-reviewed studies from 1976 to 2023. In 6 articles, the most common clinical signs for diagnosing AIP were severe dyspnea, increased expiratory effort, and grunting while breathing. In the 17 articles that provided detailed descriptions of the pathology and diagnostic features of AIP, consistent postmortem examination findings were interlobular edema and emphysema, a checkerboard appearance, and diffusely overinflated lung lobes. The most frequent histopathology findings were hyaline membranes, type II pneumocyte hyperplasia, and obliterative bronchiolitis. Although some potential etiologies, such as bovine respiratory syncytial virus (BRSV) and 3-methylindole (3MI), have been evaluated, no definitive cause has been identified consistently. Risk factors significantly associated with AIP in multiple studies included heifers, clinical onset at >45 days on feed (DOF), death at >78 DOF, and summer; the exact mechanisms remain unclear. The absence of standardized diagnostic criteria, along with a lack of research into potential effective prevention or treatment, underscore the need for further study to clarify the causes, diagnosis, and treatment of AIP in feedlot cattle.

This review summarizes current knowledge of non-infectious heart disease and congestive heart failure in feedyard cattle, emphasizing epidemiology, risk factors, timing, and diagnostic approaches. Although overall mortality risk is low, cardiac disease represents a meaningful contributor to feedyard deaths, and subclinical cardiac remodeling appears far more common than overt failure. Disease occurrence spans the feeding period, with many cases emerging near the end of the production cycle, suggesting a progressive, multifactorial process involving pulmonary vascular changes, prior disease, and possible genetic susceptibility. Interpretation of gross heart changes alone is insufficient, as morphologic remodeling does not always indicate functional failure.

Necropsies are commonly used to diagnose the causes of death in feedyard cattle, but the documentation of multiple organ system involvement and concurrent lesions is limited. This observational study aimed to determine the frequency of such findings and their associations with animal demographics. Systemic necropsies were conducted for 889 cattle mortalities with minimal autolysis across six feedyards in the Central High Plains during the summers of 2022 and 2023. Lesions and abnormalities were recorded along with arrival weight, sex, days on feed (DOFs), and number of treatments. The results showed that 72% of mortalities had more than one gross lesion, averaging 2.3 lesions per animal. The most common organ systems affected together were digestive and pulmonary (19%), followed by cardiovascular, digestive, and pulmonary (6%), and cardiovascular and pulmonary (5%). Common concurrent lesions included bronchopneumonia with an interstitial pattern (BIP) and gastrointestinal lesions (GI) (8%), bronchopneumonia and GI (7%), and acute interstitial pneumonia (AIP) and GI (3%). A generalized linear mixed effects model revealed that the likelihood of multiple lesions increased with DOFs (p = 0.02). These findings highlight the value of thorough necropsy documentation to enhance our understanding of disease and guide improved feedyard management and treatment practices.

The objective of this study was to evaluate net returns for Central U.S. high plains feedyard cattle identified with acute interstitial pneumonia (AIP) ante-mortem and post-mortem (n = 5,339) and to examine economic outcomes across sex, placement weight, and number of AIP treatments. A decision tree framework was implemented to estimate net returns of cattle identified with AIP, where decision nodes represented choices made by the producer, and branches represented potential outcomes following a decision. The initial decision node was whether to treat cattle for AIP after the first identification for illness or to sell (cull) soon after diagnosis at reduced weight and price compared to cattle in the cohort sold at finished weight. Following initial treatment, cattle that remained in the feedyard either finished (with or without further treatment), were culled, or died after additional diagnosis and treatment. Probabilities of incidents at each node were obtained from the data distribution. This research indicates that estimated net returns for feedyard cattle identified with AIP vary by sex, placement weight, and number of AIP treatments. The expected net return to feeding healthy cattle was $193.67/animal, while the expected net return for cattle that finished after AIP treatment was -$639.71/animal for cattle treated once for AIP, -$612.41/animal for those treated twice for AIP, and -$529.57/animal for those treated three or more times for AIP. However, other health indicators and risk factors not included in this analysis should be considered when deciding whether to keep or cull feedyard cattle identified with AIP.

Acute interstitial pneumonia (AIP) in feedyard cattle is a re­spiratory condition characterized by sudden onset of respira­tory distress and, often, rapid mortality. The exact etiology of AIP remains unclear and multiple risk factors are hypoth­esized to contribute to AIP development. The objective of this retrospective study was to determine the probability of at least one AIP mortality occurring in a cohort (AIPMort) and potential associations with cohort arrival characteristics and disease incidence in the first 45 days-on-feed. Variables analyzed included sex, head received, arrival weight, arrival month, bovine respiratory disease (BRD) morbidity and mor­tality, and digestive disease morbidity and mortality. Cohort and corresponding individual animal treatment records were acquired from 20 feedyards in the United States, resulting in 27,324 cohorts over 4 years. At least 1 AIP mortality was pres­ent in 5,525 (20.2%) cohorts. All risk factors were significantly associated with AIPMort. Heifer cohorts were more likely (19.5% ± 0.048) to experience AIPMort than steer cohorts (13.3% ± 0.035). Cohorts with greater than 5% BRD morbidity in the first 45 days-on-feed were more likely to experience an AIPMort (20.2% ± 0.049) than cohorts that had 0% morbidity (8% ± 0.025). Improved understanding of risk factors associ­ated with AIPMort can be valuable for managing cohorts.

OBJECTIVE To use a novel approach of targeted thoracic point-of-care ultrasound (TT-POCUS) of the caudodorsal right lung to determine potential associations between TT-POCUS measurements and the presence of interstitial pneumonia (IP) in feedyard cattle. METHODS Cross-sectional study evaluated feedyard animals (n = 62; 358.4 +/- 10.5 kg; heifer, n = 38; steer, n = 24) using TT-POCUS at time of respiratory disease treatment and microscopic assessment of lesions at subsequent mortality. Evaluations took place from July through December 2023. Pulmonary samples were collected at necropsy for histopathologic assessment, and lesions were used to diagnose IP or non-IP. Statistical models determined potential associations between IP, cattle demographic, and TT-POCUS measured variables. RESULTS Evaluations of animals enrolled (n = 62) displayed significant associations with IP, including ultrasound lung score (ULS), B-line count, A-line count, and days on feed at treatment. Cattle with a ULS of 5 had the lowest probability of IP (0.12 +/- 0.16) compared to cattle with a ULS of 2, 3, or 4 (0.72 +/- 0.18, 0.93 +/- 0.06, and 0.85 +/- 0.08, respectively). Cattle with B-line counts > 5 had a higher probability of IP (0.86 +/- 0.11) compared to cattle with 3 to 5 B-lines (0.38 +/- 0.14). The probability of IP was higher in cattle with A-line counts < 3 (0.83 +/- 0.10) compared to cattle with >= 3 A-lines (0.51 +/- 0.15). CONCLUSIONS Strategic targeted thoracic ultrasonography has potential a value of timely IP diagnosis in feedyard cattle, thereby offering important insights into therapeutic and management decisions. CLINICAL RELEVANCE Targeted thoracic ultrasonography can be utilized as a method for IP diagnosis in feedyard cattle.

Accurate prognosis at first treatment for bovine respiratory disease (BRD) is essential for timely interventions and management decisions. This cross-sectional observational study evaluated 819 commercial beef feedyard cattle at chute-side for first BRD treatment. Logistic regression models examined potential associations between two outcomes—first treatment failure (requiring additional treatment) and unfinished treatment (due to mortality or culling)—and several explanatory variables, including sex, days on feed, bodyweight, breed, pulse oximetry, lung auscultation scores, and ultrasound lung scores (ULS) measured in the caudo-dorsal lung region. Animals that ultimately did not finish treatment were significantly more likely to present a ULS of 5 (74%) compared with those scored 1–4 (18–38%). Similarly, cattle with a ULS of 5 had a much higher probability of first treatment failure (74%) than those with scores of 1–3 (35–41%). Moreover, three or more B-lines in the ultrasound image or a “moth sign” finding were both strongly associated with increased probability of negative outcomes. These results highlight key ultrasound-based and demographic factors that serve as practical prognostic indicators for cattle at the onset of BRD treatment.

Predictive models use historical data to predict a future event and can be applied to a wide variety of tasks. A broader evaluation of the cattle literature is required to better understand predictive model performance across various health challenges and to understand data types utilized to train models. This narrative review aims to describe predictive model performance in greater detail across various disease outcomes, input data types, and algorithms with a specific focus on accuracy, sensitivity, specificity, and positive and negative predictive values. A secondary goal is to address important areas for consideration for future work in the beef cattle sector. In total, 19 articles were included. Broad categories of disease were covered, including respiratory disease, bovine tuberculosis, and others. Various input data types were reported, including demographic data, images, and laboratory test results, among others. Several algorithms were utilized, including neural networks, linear models, and others. Accuracy, sensitivity, and specificity values ranged widely across disease outcome and algorithm categories. Negative predictive values were greater than positive predictive values for most disease outcomes. This review highlights the importance of utilizing several performance metrics and concludes that future work should address prevalence of outcomes and class-imbalanced data.

Metaphylaxis, the application of an antimicrobial to a cohort of cattle at arrival to a feedyard, is an important bovine respiratory disease (BRD) control strategy for certain cattle populations. Predictive modeling techniques could be used to assist in determining which cohorts should receive metaphylaxis based on a desired economic outcome instead of subjectively. The study objective was to evaluate predictive models trained with cattle demographic variables to determine which cohorts should receive metaphylaxis based on an economic evaluation of highest net returns and to elucidate the benefit to model performance with the addition of origin and external economic variables. Data from 16,368 cattle cohorts were used to build four predictive models: boosted decision tree, logistic regression, neural network, and random forest. Area under the Receiver Operating Characteristics curve (AUC-ROC) was used to evaluate model performance. The same algorithms were used to compare adding origin and external economic data to the baseline models. Overall, model performance was high with AUC-ROC values ranging from 0.80 to 0.93 in the baseline models. Adding external economic variables such as commodity futures prices increased performance (AUC-ROC=0.92-0.94). Adding origin data, such as city and state, resulted in poorer performance (AUC-ROC=0.79-0.89). The combination of external economic data and origin resulted in intermediate AUC-ROC values (AUC-ROC=0.87-0.91). The study demonstrated that predictive models can be used successfully to select an optimal metaphylaxis strategy as determined by economic evaluation for cattle arriving at the feedyard.

Chute side diagnostics offer an improved prognostic accuracy for diseased cattle. Determining prognosis for cattle chroni­cally ill with pneumonia is a critical management issue and im­pacts both animal welfare and antimicrobial stewardship. This study aims to determine potential associations between param­eters and chute side evaluations at the time of treatment with negative (mortality/culling) outcomes. Differentiating between recoverable/non-recoverable animals is valuable information at time of treatment that can inform management decisions.

Limited information is available describing mortalities of dairy and beef-dairy-cross calves in calf ranches. Study objectives were to report frequency of gross mortal­ity diagnoses at necropsy in calf ranches and determine associations of age with diagnosis. Necropsies (n = 211) were performed at 2 Kansas calf ranches by field technicians with confirmed diagnoses by a single veterinarian. Mortality diagnoses were categorized as gastrointestinal (GI), respiratory (RESP), septicemia or other based on gross lesions. A subset of calves had age data (n = 145) which were categorized as (1 to 29, 30 to 59, 60 to 89, and greater than 90 days). A generalized linear model was used to evaluate probability of being classified as RESP or GI diagno­ses based on breed type, sex and age categories. Gross necrop­sy revealed 71.1% (150/211) of mortalities were categorized as RESP, 18.5% (39/211) as GI, 7.1% (15/211) as septicemia, and 3.3% (7/211) as other. Breed type and sex were not associated with probability of RESP or GI diagnosis. Calves greater than 60 days of age were at greater (P < 0.05) risk (88 ± 4%) for RESP diagnoses compared to calves less than 30 days (37 ± 8%). Probability of GI diagnosis (46 ± 8%) was greater (P < 0.05) for calves less than 30 days compared to calves between 60 and 89 days (5 ± 3%). The frequency of multiple disease processes em­phasizes the importance of necropsy to determine diagnosis in each case. These data add valuable information about mor­talities in calf ranches.

Feedlot cattle are evaluated visually for signs of disease and to determine subsequent treatment. Hydration status is difficult to measure in feedlot cat­tle, and reference ranges are often based on other cattle pro­duction systems. The objective of this study was to determine the association of clinical markers of hydration at the time of treatment with packed cell volume (PCV) as an indicator of hydration status and treatment outcomes. Cattle treated for respiratory disease (n = 107) were examined to determine eye globe recession, skin tent, mucous membrane quality, capil­lary refill time, rectal temperature and weight. Dehydration was defined as a PCV greater than 46% (n = 9). Animals were followed for 90 days post-enrollment to determine outcomes. Treatment failure was defined as a retreatment for any reason or death due to any cause. Final outcome (died or survived) was also evaluated. Associations between predictor variables and these 3 outcomes (dehydration, treatment failure, final outcome) were determined in 3 generalized linear mixed mod­els. There were no significant associations between predic­tors and dehydration. Weight less than 700 lbs (317 kgs). was associated with an increased treatment failure probability, and abnormal mucous membrane quality was associated with a higher probability of death within the 90 days. This study shows that common markers of hydration status may not be useful in determining dehydration in feedlot cattle. However, weight and mucous membrane quality could be useful indi­cators of outcome. A larger sample size with a more diverse cattle population is needed to validate these results.