Over a two-year period, Mannheimia haemolytica (MH; n = 113), Pasteurella multocida (PM; n = 47), Histophilus somni (HS; n = 41) and Mycoplasma bovis (MB; n = 227) were isolated from bovine lung tissue at necropsy from cattle raised conventionally (CON, n = 29 feedlots) or without antimicrobials [natural (NAT), n = 2 feedlots]. Excluding MB, isolates were assayed by PCR to detect the presence of 13 antimicrobial resistance (AMR) genes and five core genes associated with integrative and conjugative elements (ICEs). Antimicrobial susceptibility phenotypes and minimum inhibitory concentrations (MICs, µg/mL) were determined for a subset of isolates (MH, n = 104; PM, n = 45; HS, n = 23; and MB, n = 61) using Sensititre analyses. A subset of isolates (n = 21) was also evaluated by whole-genome sequencing (WGS) based on variation in AMR phenotype. All five ICE core genes were detected in PM and HS by PCR, but only 3/5 were present in MH. Presence of mco and tnpA ICE core genes in MH was associated with higher MICs (p < 0.05) for all tetracyclines, and 2/3 of all macrolides, aminoglycosides and fluoroquinolones evaluated. In contrast, association of ICE core genes with MICs was largely restricted to macrolides for PM and to individual tetracyclines and macrolides for HS. For MH, the average number of AMR genes markedly increased (p < 0.05) in year 2 of the study due to the emergence of a strain that was PCR positive for all 13 PCR-tested AMR genes as well as two additional AMR genes (aadA31 and bla_ROB-1) detected by WGS. Conventional management of cattle increased (p < 0.05) MICs of tilmicosin and tulathromycin for MH; neomycin and spectinomycin for PM; and gamithromycin and tulathromycin for MB. The average number of PCR-detected AMR genes in PM was also increased (p < 0.05) in CON mortalities. This study demonstrates increased AMR especially to macrolides by bovine respiratory disease organisms in CON as compared to NAT feedlots and a rapid increase in AMR following dissemination of strain(s) carrying ICE-associated multidrug resistance.

Castration is one of the most common procedures performed on beef and dairy cattle. The objective of the study was to determine the efficacy of meloxicam oral suspension in reducing pain and inflammation in calves following band or surgical castration. Two identical trials with the exception of the method of castration (Band Castration Study 1 and Surgical Castration Study 2) were conducted. Sixty (60) healthy Holstein calves 4 to 5 months of age (138–202 Kg) were used. Animals received either Meloxicam Oral Suspension at a dose of 1 mg/kg BW (n = 15 Study 1 and 15 Study 2) or Saline (n = 15 Study 1 and 15 Study 2) 2 h before castration. Physiological (Heart Rate, Plasma Cortisol and Plasma Substance P) and Behavioral (Visual Analog Scale (VAS), Accelerometers and tail Pedometers) evaluations were conducted before (day -1) and after Castration (Day 0, 1, 2, 3). Inflammation was evaluated daily by providing an individual animal score (Study1) or with a measurement of scrotal thickness (Study 2). Heart rates were significantly greater in control animals following band and surgical castration. Plasma cortisol and substance P were significantly reduced in animals receiving Meloxicam Oral Suspension. Control animals had significantly greater VAS scores. Accelerometers showed that meloxicam treated animals had a significantly greater motion index and number of steps as well as less % time lying and number of lying bouts. The scrotal inflammation (based on scrotal swelling) was significantly decreased in the meloxicam treated animals compared to the control animals on day 1, day 2 and 3. Meloxicam Oral Suspension was able to significantly reduce the display of painful behaviors and physiological responses to pain in band castrated and surgical castrated calves for up to 72 h following a single oral treatment of 1 mg/kg body weight. Meloxicam Oral Suspension was able to significantly reduce scrotal inflammation in band castrated and surgical castrated calves.

This study investigated the effects of dystocia on milk production, somatic cell count, reproductivity, disease, and milk production. A total of 2159 cows across 21 dairy farms in Alberta, Canada were enrolled in this study. Multivariable models were created to explore associations between outcome variables and calving ease score. In total, 89.5% of calvings were unassisted, 6.1% were an easy pull, and 4.3% were a moderate–hard pull. Cows that had a moderate–hard pull produced 4.01 kg less milk, 0.12 kg less volume of milk fat, and 0.12 kg less milk protein per day than those that had an unassisted calving. No difference was found between calving ease groups with respect to SCC. Cows with a moderate or hard pull produced 510 kg less milk per lactation than unassisted cows. Cows with a moderate to high level of assistance at birth had a higher hazard of being culled over the duration of their lactation. Cows with an easy pull had increased odds of developing a retained placenta. It is evident that assistance at calving, particularly a moderate–hard pull, is associated with significant impacts on future milk production and risk of being culled; therefore, efforts should be made to minimize dystocia and prevent these impacts.

Castration is among the most common management procedures performed in the dairy and beef cattle industries and is mainly performed by surgery or elastic banding. Despite the various benefits of castration, all methods produce pain and distress. Castration by banding is simple, inexpensive, produces fewer complications, and can be performed in a high-throughput manner. Because lidocaine, a local anesthetic, can be delivered to trauma sites topically, we have formulated lidocaine-loaded castration bands (LLBs) to deliver local pain relief to calves during banded castration. The initial lidocaine content of three band types developed was between 80 and 200 mg per band. The transfer kinetics of lidocaine into tissue was determined in vitro, indicating a rapid release for the first 30 min, followed by a slow release lasting at least 48 h. Furthermore, the lidocaine delivery and pain mitigation effects of these LLBs were compared to standard lidocaine injections in vivo. Field studies indicated that LLBs performed at least as well as lidocaine injections for short-term lidocaine delivery into tissues and pain mitigation. Moreover, LLBs significantly outperformed lidocaine injections for long-term delivery and pain mitigation. The concentrations of lidocaine in the LLB-treated tissue samples were generally in the range of 0.5–3.5 mg of lidocaine per gram of tissue and were overall highest after 6 h. Lidocaine-loaded elastration bands deliver therapeutic quantities of lidocaine into scrotal tissues over a period of at least seven days in cattle. This approach would provide long-term pain mitigation to the animals and, by avoiding surgery or the administration of injections, would also decrease the time and handling costs for the producer.

This study aimed to assess the effective tissue concentrations of the current standard of care for pain mitigation in calves during castration (injectable lidocaine) and to assess the ability of a lidocaine-loaded elastration band (LLB) to deliver effective concentrations into the scrotal tissue over time. This study comprised two different trials: (1) effective concentrations of injectable lidocaine in the scrotal tissue; and (2) the in vivo delivery of effective concentrations of lidocaine from LLBs placed on the calf scrotums. Sensation in the scrotal tissue was assessed by electrocutaneous stimulation. Injectable lidocaine allowed for short-term anesthesia for up to 60 min, highlighting the importance of finding additional strategies to mitigate long-term pain. An elastomeric ligation band impregnated with lidocaine could provide a suitable alternative, as it yielded tissue levels of lidocaine that approached EC₅₀ and exceeded EC₉₅ at 2 and 72 h following application, respectively, and remained above those levels for at least 28 days after application. Further studies are warranted to compare the use of LLBs to injectable local anesthetics.