Characterization of the hoof bacterial communities in feedlot cattle affected with digital dermatitis, foot rot or both using a surface swab technique.

BACKGROUND: Lameness is defined as altered or abnormal gait due to dysfunction of the locomotor system, and is a health issue of feedlot cattle, having major economic, labour, and welfare implications. Digital dermatitis (DD-a lesion of the plantar surface of the foot) and foot rot (FR-affects the interdigital cleft) are common infectious causes of lameness in feedlots. These hoof lesions can occur alone or in combination (DD + FR) in the same hoof. A total of 208 hoof swabs were collected from three commercial feedlots located in southern Alberta. Every lesion sample was matched with a corresponding control skin sample taken from a healthy contralateral foot. Control skin samples were also collected from cattle with no lesion on any feet. Bacterial communities of three types of hoof lesions (DD, DD + FR, FR) and healthy skin were profiled using 16S amplicon sequencing. RESULTS: Alpha diversity analysis revealed a lower bacterial diversity on DD and FR lesions compared to control skin. Beta diversity analysis showed that bacterial communities of DD, FR, and DD + FR lesions were distinct from those of the control skin. While the impact of feedlot was minimal, lesion type contributed to 22% of the variation observed among bacterial communities (PERMANOVA-R = 0.22, P < 0.01). Compared to the corresponding control skin, there were 11, 12, and 3 differentially abundant (DA) bacterial genera in DD, DD + FR, and FR lesions, respectively. CONCLUSIONS: The bacterial community description of a DD + FR lesion is a novel finding. Not only did lesions lead to altered bacterial communities when compared to healthy skin, but the composition of those communities also differed depending on the hoof lesion. The 16S amplicon sequencing of surface swabs has significant value as a research tool in separating different hoof lesions and can provide additional insights to the polybacterial etiology of DD and FR in feedlot cattle.

Pharmacokinetics of oral and subcutaneous meloxicam: Effect on indicators of pain and inflammation after knife castration in weaned beef calves.

Oral meloxicam is labelled for reducing pain and inflammation associated with castration in cattle in Canada, however, subcutaneous meloxicam is only labelled for pain associated with dis-budding and abdominal surgery. The aim of this project was to determine the pharmacokinetic profile of oral (PO; 1.0 mg/kg BW) and subcutaneous meloxicam (SC; 0.5 mg/kg BW), and to assess the effect of meloxicam on physiological and behavioural indicators of pain associated with knife castration in 7-8 month old calves. Twenty-three Angus crossbred beef calves (328 ± 4.4 kg BW) were randomly assigned to two treatments: PO n = 12 or SC n = 11 administration of meloxicam immediately before knife castration. Physiological parameters included salivary and hair cortisol, substance P, haptoglobin, serum amyloid-A, weight, complete blood count, scrotal and rectal temperature. Behavioural parameters included standing and lying behaviour, pen behaviour and feeding behaviour. Data were analyzed using PROC GLIMMIX (SAS), with repeated measures using mixed procedures including treatment as a fixed effect and animal and pen as a random effect. The pharmacokinetic profile of the drug including area under the curve, volume of distribution and clearance was greater (P < 0.05) in PO than SC calves. After surgery, substance P concentrations, white blood cell counts (WBC), weight and lying duration were greater (P < 0.05) in PO than SC calves, while scrotal circumference was lower (P < 0.05) in PO calves than SC calves. Although statistical differences were observed for pharmacokinetic, physiological and behavioural parameters differences were small and may lack biological relevance.

Effect of meloxicam and lidocaine administered alone or in combination on indicators of pain and distress during and after knife castration in weaned beef calves.

To assess the effect of meloxicam and lidocaine on indicators of pain associated with castration, forty-eight Angus crossbred beef calves (304 ± 40.5 kg of BW, 7-8 months of age) were used in a 28 day experiment. The experiment consisted of a 2 × 2 factorial design where main factors included provision of analgesia and local anaesthesia. Analgesia consisted of: no-meloxicam (N; n = 24) single s.c. administration of lactated ringer's solution and meloxicam (M; n = 24) single dose of 0.5 mg/kg of s.c. meloxicam. Local anesthesia consisted of: no-lidocaine (R; n = 24) ring block administration of lactated ringer's solution or lidociane (L; n = 24) ring block administration of lidocaine. To yield the following treatments: no meloxicam + no lidocaine (N-R; n = 12), no meloxicam + lidocaine (N-L; n = 12), meloxicam + no lidocaine (M-R; n = 12) and meloxicam + lidocaine (M-L; n = 12). Salivary cortisol concentrations were lower (lidocaine × time effect; P < 0.01) in L calves than R calves 0.5 and 1 hours after castration, while concentrations were lower (meloxicam × time effect; P = 0.02) in M calves than N calves at 2, 4 and 48 hours. The serum amyloid-A concentrations were greater (lidocaine × time effect; P < 0.01) in R calves than L calves on days 1, 3, 21 and 28 after castration. Haptoglobin concentrations were greater (meloxicam × time effect; P = 0.01) in N calves than M calves 24 and 48 hours after castration. Lower (lidocaine effect; P < 0.01) visual analog scale (VAS) scores, leg movement frequencies and head movement distance were observed in L calves than R calves at the time of castration. Escape behaviour during castration was lower (lidocaine effect; P < 0.05) in L calves than R calves based on data captured with accelerometer and head gate devices. Scrotal circumference had a triple interaction (lidocaine × meloxicam × time; P = 0.03), where M-R calves had greater scrotal circumference than M-L calves 28 d after castration, but no differences were observed between both groups and N-R and N-L calves. No differences (P > 0.05) were observed for average daily gain (ADG), weights or feeding behaviour. Overall, both lidocaine and meloxicam reduced physiological and behavioural indicators of pain. Although there was only one meloxicam × lidocaine interaction, lidocaine and meloxicam reduced physiological and behavioural parameters at different time points, which could be more effective at mitigating pain than either drug on its own.

Effect of a single dose of subcutaneous meloxicam prior to band or knife castration in 1-wk-old beef calves: II. Inflammatory response and healing.

The aim of this study was to evaluate the effect of a single dose of subcutaneous (s.c.) meloxicam administered at the time of knife and band castration on inflammatory response and wound healing over 56-d post-castration. Seventy-two Angus crossbred calves (47.3 ± 6.70 kg of body weight [BW] and 7 to 8 d of age) were randomly assigned according to a 3 × 2 factorial design assessing castration method: sham (CT), band (BA), and knife (KN) castration, and pain mitigation: non-medicated (NM) and medicated calves (M) injected s.c. with meloxicam (0.5 mg/kg of BW). Calf BW, rectal temperature, swelling ("0": no swelling; "4": swelling needing intervention) and healing score ("1" to "5" with "5" being completely healed), scrotal circumference, and maximum scrotal temperature were measured on d -1, immediately before castration (d 0), and weekly thereafter over a 56-d period. Blood samples for haptoglobin (Hp), serum amyloid-A (SAA), and complete blood cell count were collected according to the same schedule. Hair samples were collected on d -1, 28, and 56 to determine cortisol concentrations. Standing and lying behaviors were measured using accelerometers that were placed on the calves on d -1 until d 35, and visual observations of behaviors related to pain were recorded once a week for 35 d. Knife-castrated calves achieved swelling scores of "3" and "2" between d 7 and 14, which was sooner (Z< 0.05) than in BA calves (from d 14 to 35). In addition, greater (P = 0.03) concentrations of SAA were observed in BA calves (76.9 ± 0.12 g/liter) compared with CT (57.6 ± 0.12 g/liter) and KN (51.6 ± 0.12 g/liter) from d 7 to 35. Healing scores of "2" and "4" tended to be achieved sooner (Z < 0.10) in KN calves than in BA calves, although healing scores of "3" tended to be achieved sooner (Z < 0.10) in BA calves than KN calves. No differences (P > 0.10) were observed among treatments for hair cortisol on d -1 and 28, but on d 56, hair cortisol concentrations in BA-NM calves were greater (P > 0.05) than for CT-NM, BA-M, KN-NM, and KN-M, and tended to be greater (P = 0.08) than for CT-M calves. Lying duration tended (P = 0.10) to be greater and suckling behavior tended (P = 0.08) to be lower in NM than M calves. A single s.c. injection of meloxicam did not reduce long-term inflammatory responses or improve wound healing; however, it may be useful in reducing pain and stress in band castrated calves as evidenced by reduced hair cortisol concentrations up to 56 d post-castration.

Effect of subcutaneous meloxicam on indicators of acute pain and distress after castration and branding in 2-mo-old beef calves1,2.

The aim of this study was to assess knife castration and knife castration + branding in 2-mo-old calves, and the effect of a single dose of s.c. meloxicam at mitigating pain indicators. Seventy-one Angus crossbred bull calves (128 ± 18.5 kg of BW) were used in a 3 × 2 factorial design where main factors included procedure: sham (control calves, CT; n = 23), knife (KN; n = 24) or knife + branding (BK; n = 24), and medication: single s.c. administration of lactated ringer solution (NM; n = 35) or a single dose of 0.5 mg/kg of s.c. meloxicam (M; n = 36). Physiological samples were collected at T0, 60, 90, 120, and 180 min and on days 1, 2, 3, and 7 after procedure, whereas behavioral observations were evaluated at 2 to 4 h and 1, 2, 3, and 7 days after procedure. A procedure × time effect (P < 0.01) was observed for cortisol, where KN and BK calves had greater (P ≤ 0.01) cortisol concentrations than CT calves 60 min after the procedure, whereas BK calves had the greatest (P < 0.05) cortisol concentrations, followed by KN calves and by CT calves 90, 120, and 180 min after the procedure. A procedure × time effect (P = 0.01) was observed for tail flicks, where KN and BK calves had a greater (P < 0.05) number of tail flicks than CT calves on days 1 and 3, whereas BK calves had the greatest number of tail flicks, followed by KN calves, and then by CT calves on day 2. Haptoglobin had a procedure × medication × time interaction (P = 0.05), where BK-NM calves had greater haptoglobin concentrations than BK-M, KN-M, and CT calves on days 1 and 3, whereas BK-NM and KN-NM calves had greater haptoglobin concentrations than BK-M, KN-M, and CT calves on day 2 after the procedure. Lying duration and tail flicks had a medication effect (P = 0.04; P < 0.01) where M calves had greater (P < 0.05) lying duration and lower (P < 0.05) number of tail flicks than NM calves 2 to 4 h after procedure. No medication effects (P > 0.10) were observed for salivary cortisol, substance P, and scrotal temperature minutes after the procedure or for cortisol, substance P, serum amyloid-A, stride length, or behavioral observations days after the procedure. Overall, BK calves presented greater physiological and behavioral indicators of acute pain than KN calves, suggesting that the combination of knife castration + branding was more painful. Meloxicam administered s.c. was effective at reducing physiological and behavioral indicators of acute pain associated with knife castration and knife castration + branding.

Use of topical healing agents on scrotal wounds after surgical castration in weaned beef calves.

Angus bulls (n = 48) were randomly assigned to control (castrated without the application of a postoperative healing agent) or surgical castration followed by either the application of a topical germicide, aluminum powder spray, or liquid bandage. The objective of this study was to determine the efficacy of commercial topical healing agents in improving wound healing and reducing inflammation and secondary infection after surgical castration. Indicators of wound healing included scrotal area temperature (determined by infrared thermography), scrotal circumference, clinical state of the scrotum score, and the wound healing score. Pain sensitivity was measured using a Von Frey anesthesiometer. The healing agents used in this study did not improve indicators of healing such as swelling and healing rate scores or indicators of inflammation including scrotal temperature and circumference of surgical castration lesions. Pain sensation associated with surgical castration was found to last 35 d after the procedure.

Usage d'agents cicatrisants topiques sur des blessures scrotales après la castration chirurgicale chez des veaux de boucherie sevrés. Quarante-huit taureaux Angus ont été assignés au hasard à la castration témoin (castration sans l'application d'un agent cicatrisant postopératoire) ou à la castration chirurgicale suivie soit de l'application d'un germicide topique, d'un poudre à l'aluminium en vaporisateur ou d'un pansement liquide dans le but de déterminer l'efficacité des agents cicatrisants topiques commerciaux pour l'amélioration de la guérison des plaies et la réduction de l'inflammation et de l'infection secondaire après la castration chirurgicale. Les indicateurs de cicatrisation des plaies incluaient la température de la région scrotale déterminée par thermographie infrarouge, la circonférence scrotale, le pointage de l'état clinique du scrotum et le pointage de la cicatrisation de la plaie; et la sensibilité à la douleur mesurée à l'aide d'un anesthésiomètre Von Frey. Les agents cicatrisants utilisés dans cette étude n'ont pas amélioré les indicateurs de cicatrisation comme l'enflure et les notes de la rapidité de cicatrisation ou des indicateurs de l'inflammation qui incluaient la température scrotale et la circonférence des lésions de castration chirurgicale. Il a été constaté que la sensation de douleur associée à la castration chirurgicale durait 35 jours après l'intervention.(Traduit par Isabelle Vallières).