Comprehensive Outcomes Affected by Antimicrobial Metaphylaxis of Feedlot Calves at Medium-Risk for Bovine Respiratory Disease from a Randomized Controlled Trial.

The objectives were to evaluate the effects of metaphylaxis (META) and pull-and-treat (PT) programs on health, antimicrobial use, beef production, economics, and greenhouse gas emissions in cattle at medium risk for bovine respiratory disease (BRD). A randomized complete block design was used at two US commercial feedlots. Steers and heifers [2366 total; 261 (±11.0) kg initial weight] were blocked by sex and feedlot arrival, and allocated to one of two pens within a block (16 pens total, eight blocks). Pens were randomly assigned to treatment: META, tulathromycin injection at initial processing; or PT, tulathromycin injection only for first clinical BRD treatment. Data were analyzed with linear and generalized linear mixed models. There was greater BRD morbidity in PT than META cattle (17.2% vs. 7.3% respectively; p < 0.01), and greater total mortality (2.5% vs. 1.1% respectively; p = 0.03). Per animal enrolled, 1.1 antimicrobial doses were used for META compared to 0.2 for PT (p < 0.01). Per animal enrolled, final live (p = 0.04) and carcass (p = 0.08) weights were greater for META than PT; however, net returns ($/animal) were not significantly different (p = 0.71). Compared to PT, total lifetime estimated CO2 equivalent emissions from production were reduced by 2% per unit of live weight for META (p = 0.09). While antimicrobial use was reduced with PT, there may be substantial negative impacts on other outcomes if META was not used in this type of cattle population.

The application, value, and impact of outcomes research in animal health and veterinary medicine.

Outcomes research is a relatively recent field of study in animal health and veterinary medicine despite being well-established in human medicine. As the field of animal health is broad-ranging in terms of animal species, objectives, research methodologies, design, analysis, values, and outcomes, there is inherent versatility in the application and impact of the discipline of outcomes research to a variety of stakeholders. The major themes of outcomes relevant to the animal health industry have been distilled down to include, but are not limited to, health, production, economics, and marketing. An outcomes research approach considers an element of value along with an outcome of interest, setting it apart from traditional research approaches. Elements of value are determined by the stakeholders' use of products and/or services that meet or exceed functional, emotional, life-changing, and/or societal needs. Stakeholder perception of value depends on many factors such as the purpose of the animal (e.g., companion vs. food production) and the stakeholder's role (e.g., veterinarian, client, pet-owner, producer, consumer, government official, industry representative, policy holder). Key areas of application of outcomes research principles include comparative medicine, veterinary product development, and post-licensure evaluation of veterinary pharmaceuticals and/or biologics. Topics currently trending in human healthcare outcomes research, such as drug pricing, precision medicine, or the use of real-world evidence, offer novel and interesting perspectives for addressing themes common to the animal health sector. An approach that evaluates the benefits of practices and interventions to veterinary patients and society while maximizing outcomes is paramount to combating many current and future scientific challenges where feeding the world, caring for our aging companion animals, and implementing novel technologies in companion animal medicine and in production animal agriculture are at the forefront of our industry goals.

A systematic review and meta-analysis of published literature on prevalence of non-O157 Shiga toxin-producing Escherichia coli serogroups (O26, O45, O103, O111, O121, and O145) and virulence genes in feces, hides, and carcasses of pre- and peri-harvest cattle worldwide.

OBJECTIVE: The objective of this study was to summarize peer-reviewed literature on the prevalence and concentration of non-O157 STEC (O26, O45, O103, O111, O121, and O145) serogroups and virulence genes (stx and eae) in fecal, hide, and carcass samples in pre- and peri-harvest cattle worldwide, using a systematic review of the literature and meta-analyses. DATA SYNTHESIS: Seventy articles were eligible for meta-analysis inclusion; data from 65 articles were subjected to random-effects meta-analysis models to yield fecal prevalence estimates. Meta-regression models were built to explore variables contributing to the between-study heterogeneity. RESULTS: Worldwide pooled non-O157 serogroup, STEC, and EHEC fecal prevalence estimates (95% confidence interval) were 4.7% (3.4-6.3%), 0.7% (0.5-0.8%), and 1.0% (0.8-1.1%), respectively. Fecal prevalence estimates significantly differed by geographic region (P < 0.01) for each outcome classification. Meta-regression analyses identified region, cattle type, and specimen type as factors that contribute to heterogeneity for worldwide fecal prevalence estimates. CONCLUSIONS: The prevalence of these global foodborne pathogens in the cattle reservoir is widespread and highly variable by region. The scarcity of prevalence and concentration data for hide and carcass matrices identifies a large data gap in the literature as these are the closest proxies for potential beef contamination at harvest.

Effectiveness of a Direct-Fed Microbial Product Containing Lactobacillus acidophilus and Lactobacillus casei in Reducing Fecal Shedding of Escherichia coli O157:H7 in Commercial Feedlot Cattle.

The objective of this study was to evaluate the effectiveness of a direct-fed microbial (DFM) product in reducing fecal shedding of Escherichia coli O157:H7 in finishing commercial feedlot cattle in Kansas (KS) and Nebraska (NE). Utilizing a randomized complete block design within the feedlot (KS, n = 1; NE, n = 1), cattle were randomly allocated to 20 pens, grouped in blocks of two based on allocation date, and then, within the block, randomly assigned to a treatment group (DFM or negative control). The DFM product was included in the diet at a targeted daily dose of 1 × 109 colony-forming units (CFU) of the Lactobacillus acidophilus and Lactobacillus casei combination per animal for at least 60 d before sampling. Feedlots were sampled for four consecutive weeks; weekly sampling consisted of collecting 20 pen floor fecal samples per pen. Fecal samples were subjected to culture-based methods for detection and isolation of E. coli O157, and positive samples were quantified using real-time polymerase chain reaction. Primary outcomes of interest were fecal prevalence of E. coli O157:H7 and E. coli O157 supershedding (≥104 CFU/g of feces) prevalence. Data for each feedlot were analyzed at the pen level using mixed models accounting for the study design features. Model-adjusted mean E. coli O157:H7 fecal prevalence estimates (standard error of the mean [SEM]) for DFM and control groups were 8.2% (SEM = 2.2%) and 9.9% (SEM = 2.5%) in KS and 14.6% (SEM = 2.8%) versus 14.3% (SEM = 2.6%) in NE; prevalence did not differ significantly between treatment groups at either site (KS, p = 0.51; NE, p = 0.92). Mean E. coli O157 supershedding prevalence estimates for DFM and control groups were 2.2% (SEM = 0.7%) versus 1.8% (SEM = 0.7%) in KS (p = 0.66) and 6.7% (SEM = 1.5%) versus 3.2% (SEM = 1.0%) in NE (p = 0.04). In conclusion, administering the DFM product in the finishing diet of feedlot cattle did not significantly reduce E. coli O157:H7 fecal prevalence or supershedding prevalence in study pens at either commercial feedlot.

A complete cross-over design evaluating canine acceptance of Carprieve® and Rimadyl® carprofen chewable tablets in healthy dogs.

BACKGROUND: Osteoarthritis (OA) affects nearly 20% of all dogs greater than one year of age. Clinical signs include pain, discomfort, lameness, and ultimately lead to disability. Although there is currently no known cure, there are many therapeutic options that can slow the progression and alleviate the associated signs. There is ample supportive evidence demonstrating the efficaciousness of carprofen, a non-steroidal anti-inflammatory drug, in managing signs of OA. Since the approval of the pioneer product (Rimadyl®, Zoetis; Kalamazoo, Michigan), the United States Food and Drug Administration (FDA) has assented to several other generic, bioequivalent products. The objective of this 2 × 2 complete cross-over design was to assess the acceptance of two bioequivalent carprofen liver-flavored chewable tablets (containing 25 mg carprofen), Rimadyl® and Carprieve® (Norbrook Laboratories Limited; Newry, Northern Ireland) in 37 healthy purpose-bred dogs. RESULTS: Overall, 73.0% (27/37) and 70.3% (26/37) of dogs voluntarily accepted Rimadyl® and Carprieve®, respectively. Considering acceptability tests paired by individual dog, 64.9% of dogs (n = 24) voluntarily accepted both Rimadyl® and Carprieve® chewable tablets whereas 21.6% (8) of dogs denied or partially accepted both products offered. Three dogs (8.1%) fully accepted Rimadyl® but did not accept Carprieve®. Conversely, two dogs (5.4%) fully accepted Carprieve® but did not accept Rimadyl®. Canine acceptability did not significantly differ between Carprieve® and Rimadyl® carprofen chewable tablets (P = 0.65). CONCLUSIONS: Utilizing a 2 × 2 complete cross-over design, this study provides evidence that canine acceptability of a single-dose did not differ between Carprieve® and Rimadyl® chewable tablets.

Feedlot- and Pen-Level Prevalence of Enterohemorrhagic Escherichia coli in Feces of Commercial Feedlot Cattle in Two Major U.S. Cattle Feeding Areas.

The objective of this study was to determine feedlot- and pen-level fecal prevalence of seven enterohemorrhagic Escherichia coli (EHEC) belonging to serogroups (O26, O45, O103, O111, O121, O145, and O157, or EHEC-7) in feces of feedlot cattle in two feeding areas in the United States. Cattle pens from four commercial feedlots in each of the two major U.S. beef cattle areas were sampled. Up to 16 pen-floor fecal samples were collected from each of 4-6 pens per feedlot, monthly, for a total of three visits per feedlot, from June to August, 2014. Culture procedures including fecal enrichment in E. coli broth, immunomagnetic separation, and plating on selective media, followed by confirmation through polymerase chain reaction (PCR) testing, were conducted. Generalized linear mixed models were fitted to estimate feedlot-, pen-, and sample-level fecal prevalence of EHEC-7 and to evaluate associations between potential demographic and management risk factors with feedlot and within-pen prevalence of EHEC-7. All study feedlots and 31.0% of the study pens had at least one non-O157 EHEC-positive fecal sample, whereas 62.4% of pens tested positive for EHEC O157; sample-level prevalence estimates ranged from 0.0% for EHEC O121 to 18.7% for EHEC O157. Within-pen prevalence of EHEC O157 varied significantly by sampling month; similarly within-pen prevalence of non-O157 EHEC varied significantly by month and by the sex composition of the pen (heifer, steer, or mixed). Feedlot management factors, however, were not significantly associated with fecal prevalence of EHEC-7. Intraclass correlation coefficients for EHEC-7 models indicated that most of the variation occurred between pens, rather than within pens, or between feedlots. Hence, the potential combination of preharvest interventions and pen-level management strategies may have positive food safety impacts downstream along the beef chain.

Pooling of Immunomagnetic Separation Beads Does Not Affect Detection Sensitivity of Six Major Serogroups of Shiga Toxin-Producing Escherichia coli in Cattle Feces.

Shiga toxin-producing Escherichia coli (STEC) of the serogroups O26, O45, O103, O111, O121, and O145, often called non-O157 STEC, are foodborne pathogens. Cattle are asymptomatic reservoirs for STEC; the organisms reside in the hindgut and are shed in the feces, which serve as the source of food product contaminations. Culture-based detection of non-O157 STEC involves an immunomagnetic separation (IMS) step to capture the specific serogroups in complex matrices, such as feces. The IMS procedure is time consuming and labor intensive because of the need to subject each fecal sample to six individual beads. Therefore, our objective was to evaluate whether pooling of IMS beads affects sensitivity of non-O157 STEC detection compared with using individual IMS beads. The evaluation was done by comparing detection of serogroups in feces spiked with pure cultures (experiments 1 and 2) and from feces (n = 384) of naturally shedding cattle (experiment 3). In spiked fecal samples, detection with pools of three, four, six, or seven beads was similar to, or at times higher than, detection with individual IMS beads. In experiment 3, the proportions of fecal samples that tested positive for the six serogroups as detected by individual or pooled beads were similar. Based on noninferiority tests, detection with pooled beads was not substantially inferior to detection with individual beads (P > 0.05). In conclusion, the pooling of IMS beads is a better option for detection of STEC serogroups in fecal samples compared with individual beads because the procedure saves time and labor and has the prospect of a higher throughput.

A Comparison of Culture- and PCR-Based Methods to Detect Six Major Non-O157 Serogroups of Shiga Toxin-Producing Escherichia coli in Cattle Feces.

Culture-based methods to detect the six major non-O157 (O26, O45, O103, O111, O121 and O145) Shiga toxin-producing E. coli (STEC) are not well established. Our objectives of this study were to develop a culture-based method to detect the six non-O157 serogroups in cattle feces and compare the detection with a PCR method. Fecal samples (n = 576) were collected in a feedlot from 24 pens during a 12-week period and enriched in E. coli broth at 40° C for 6 h. Enriched samples were subjected to immunomagnetic separation, spread-plated onto a selective chromogenic medium, and initially pooled colonies, and subsequently, single colonies were tested by a multiplex PCR targeting six serogroups and four virulence genes, stx1, stx2, eae, and ehxA (culture method). Fecal suspensions, before and after enrichment, were also tested by a multiplex PCR targeting six serogroups and four virulence genes (PCR method). There was no difference in the proportions of fecal samples that tested positive (74.3 vs. 77.4%) for one or more of the six serogroups by either culture or the PCR method. However, each method detected one or more of the six serogroups in samples that were negative by the other method. Both culture method and PCR indicated that O26, O45, and O103 were the dominant serogroups. Higher proportions (P < 0.05) of fecal samples were positive for O26 (44.4 vs. 22.7%) and O121 (22.9 vs. 2.3%) serogroups by PCR than by the culture method. None of the fecal samples contained more than four serogroups. Only a small proportion of the six serogroups (23/640; 3.6%) isolated carried Shiga toxin genes. The culture method and the PCR method detected all six serogroups in samples negative by the other method, highlighting the importance of subjecting fecal samples to both methods for accurate detection of the six non-O157 STEC in cattle feces.

Summer and Winter Prevalence of Shiga Toxin-Producing Escherichia coli (STEC) O26, O45, O103, O111, O121, O145, and O157 in Feces of Feedlot Cattle.

The United States Department of Agriculture Food Safety and Inspection Service has declared seven Shiga toxin-producing Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, O145, and O157) as adulterants in raw, nonintact beef products. The objective of this study was to determine the prevalence of these seven serogroups and the associated virulence genes (Shiga toxin [stx1, stx2], and intimin [eae]) in cattle feces during summer (June-August 2013) and winter (January-March 2014) months. Twenty-four pen floor fecal samples were collected from each of 24 cattle pens, in both summer and winter months, at a commercial feedlot in the United States. Samples were subjected to culture-based detection methods that included enrichment, serogroup-specific immunomagnetic separation and plating on selective media, followed by a multiplex polymerase chain reaction for serogroup confirmation and virulence gene detection. A sample was considered STEC positive if a recovered isolate harbored an O gene, stx1, and/or stx2, and eae genes. All O serogroups of interest were detected in summer months, and model-adjusted prevalence estimates are as follows: O26 (17.8%), O45 (14.6%), O103 (59.9%), O111 (0.2%), O121 (2.0%), O145 (2.7%), and O157 (41.6%); however, most non-O157 isolates did not harbor virulence genes. The cumulative model-adjusted sample-level prevalence estimates of STEC O26, O103, O145, and O157 during summer (n=576) were 1.0, 1.6, 0.8, and 41.4%, respectively; STEC O45, O111, and O121 were not detected during summer months. In winter, serogroups O26 (0.9%), O45 (1.5%), O103 (40.2%), and O121 (0.2%) were isolated; however, no virulence genes were detected in isolates from cattle feces collected during winter (n=576). Statistically significant seasonal differences in prevalence were identified for STEC O103 and O157 (p<0.05), but data on other STEC were sparse. The results of this study indicate that although non-O157 serogroups were present, non-O157 STEC were rarely detected in feces from the feedlot cattle populations tested in summer and winter months.