Efficacy of a Haemonchus contortus vaccine under field conditions in young alpacas.

Anthelmintic resistance to Haemonchus contortus creates increasing management challenges with small ruminants and camelids. The commercial vaccine, Barbervax®, contains H11 and H-gal-GP antigens, derived from gut mucosal membrane enzymes of H. contortus involved in digesting blood. Antibody neutralization of these antigens causes failure of H. contortus to digest blood, resulting in parasite death. H11 and H-gal-GP are considered "hidden" antigens, meaning the host immune system does not encounter these proteins under natural infection. Therefore, repeat immunization is required to maintain protective humoral responses. One previous study evaluated the safety of Barbervax® in camelids but the efficacy could not be assessed due to lack of successful infection in the controls. The objective of the current study was to evaluate clinical parameters of anemia, fecal egg counts (FECs), and humoral immune responses of healthy alpacas after immunizing with Barbervax® compared to non-vaccinated controls, all under natural environmental exposure on parasite-laden pastures. A crossover-like study was performed where twenty alpacas (298 ± 66 days of age) were assigned to be initially vaccinated with Barbervax® (n=10) or receive no treatment (n=10). Three doses of Barbervax® were administered at three-week intervals. Feces and blood were collected on Day -10, 0, 21, 43, 64, 85, 106, and 135 to evaluate FECs, packed cell volume (PCV), and antibody titers. Each group was kept on separate adjacent pastures. Tracer sheep (n=2 per study group) were introduced on Day 43 for a three-week period to ensure parasite acquisition. For the crossover-like component on Day 85, the initial non-vaccinated group was administered Barbervax® with dosing repeated on Day 106 and 135. Results indicated all initially vaccinated alpacas produced antibody titers to vaccine antigen that corresponded to lower mean FECs compared to the initially non-vaccinated group. A reduced mean FEC in the vaccinate group was observed 21 days after peak antibody titers. Similarly, when pooled vaccinate antibody titers were noted to wane on Day 106, an increase in FEC was observed at the following time point (Day 135). Conclusions from our study support the use of Barbervax® to reduce H. contortus burdens in alpacas. Furthermore, a less than 30-day lag time between antibody titer and resultant effect in FECs was observed. Additional studies assessing the ability of Barbervax® to reduce H. contortus burdens during subsequent grazing seasons would provide even greater information regarding the use of Barbervax® within alpaca herds to modulate H. contortus infections, refugia, and anthelmintic use.

Nasolacrimal duct obstruction prevalence is 0.3% among alpacas evaluated with ophthalmic disease at a veterinary teaching hospital between 2000 and 2023.

OBJECTIVE: To examine the prevalence of nasolacrimal duct (NLD) obstruction in hospital populations and assess signalment, diagnostics, and clinical approaches for alpacas and llamas diagnosed with NLD atresia or obstruction. ANIMALS: 29 alpacas and 2 llamas. CLINICAL PRESENTATION: Medical records were reviewed to identify camelids with NLD evaluated between 2000 and 2023. Signalment, history, physical examination data, diagnosis, and treatments were recorded. Follow-up information was gathered via phone and email questionnaire. Data were evaluated to determine prevalence and describe signalment and treatments for NLD disease. RESULTS: 31 camelids met the inclusion criteria. A total of 8,027 alpacas and 1,998 llamas were seen within the study period at 1 teaching institution. The prevalence of NLD obstruction for this population of alpacas was 0.3% (26/8,027). Nineteen of 31 (61%) camelids presented at 1 year of age or younger. The most common physical exam finding was ocular discharge (68%). The most common diagnosis was NLD atresia (16/31 [51%]). Patency was established by surgical opening or lavage of the NLD. Long-term follow-up was available for 13 alpacas and 2 llamas, of which 11 (73%) had successful outcomes. CLINICAL RELEVANCE: Results indicate that NLD obstruction is a condition that most commonly affects alpacas < 1 year of age and is associated with a good prognosis for treatment success.

Biomechanical properties of an implant designed to stabilize the coxofemoral joint following luxation show dissimilarity to the native ligament of the head of the femur in cattle.

OBJECTIVE: To improve upon the toggle-pin implant construction and develop a repeatable surgical technique to achieve coxofemoral stabilization in mature cattle. ANIMALS: 9 adult bovine cadaveric coxofemoral joints, 8 bovine femurs, 2 beef calf cadavers. PROCEDURES: Ultimate tensile strength and elongation at failure were measured for the native ligament of the head of the femur (LOHOF) harvested up to 48 hours after death, and the prosthetic prototype utilizing stainless-steel cable and prosthetic prototype utilizing nylon leader line were compared. Bovine femurs were utilized to locate the ideal and repeatable trajectory of the prosthetic ligament to exit at the origin of the LOHOF. Using fluoroscopy, thawed calf cadavers with radiopaque markers placed at sites of origin and insertion of the LOHOF were positioned to assess limb angle to maximize joint isometry resulting in the ideal placement of the LOHOF prosthesis. The study was performed between February 1, 2020, and December 1, 2021. RESULTS: The stainless-steel prototype had a significantly higher ultimate tensile strength and significantly decreased elongation at failure when compared to the LOHOF, while the nylon-based prototype had significantly decreased tensile strength and elongation at failure compared to the LOHOF. Therefore, neither prototypes were biomechanically similar to LOHOF. CLINICAL RELEVANCE: The stainless-steel prosthetic prototype shows promise to provide superior stabilization to the luxated coxofemoral joint.

Autologous platelet-rich plasma effects on Staphylococcus aureus-induced chondrocyte death in an in vitro bovine septic arthritis model.

OBJECTIVE: To investigate the chondroprotective effects of autologous platelet-rich plasma (PRP), ampicillin-sulbactam (AmpS), or PRP combined with AmpS (PRP+AmpS) in an in vitro chondrocyte explant model of bovine Staphylococcus aureus-induced septic arthritis. SAMPLE: Autologous PRP and cartilage explants obtained from 6 healthy, adult, nonlactating Jersey-crossbred cows. PROCEDURES: Autologous PRP was prepared prior to euthanasia using an optimized double centrifugation protocol. Cartilage explants collected from grossly normal stifle joints were incubated in synovial fluid (SF) alone, S aureus-inoculated SF (SA), or SA supplemented with PRP (25% culture medium volume), AmpS (2 mg/mL), or both PRP (25% culture medium volume) and AmpS (2 mg/mL; PRP+AmpS) for 24 hours. The metabolic activity, percentage of dead cells, and glycosaminoglycan content of cartilage explants were measured with a resazurin-based assay, live-dead cell staining, and dimethylmethylene blue assay, respectively. Treatment effects were assessed relative to the findings for cartilage explants incubated in SF alone. RESULTS: Application of PRP, AmpS, and PRP+AmpS treatments significantly reduced S aureus-induced chondrocyte death (ie, increased metabolic activity and cell viability staining) in cartilage explants, compared with untreated controls. There were no significant differences in chondrocyte death among explants treated with PRP, AmpS, or PRP+AmpS. CLINICAL RELEVANCE: In this in vitro explant model of S aureus-induced septic arthritis, PRP, AmpS, and PRP+AmpS treatments mitigated chondrocyte death. Additional work to confirm the efficacy of PRP with bacteria commonly associated with clinical septic arthritis in cattle as well as in vivo evaluation is warranted.

Surgical management and outcome of acquired inguinal hernias in mature bulls: 13 cases (2005-2017).

OBJECTIVE: To describe rates of surgical complications, survival, and return to breeding soundness following herniorrhaphy for bulls with inguinal hernias. ANIMALS: 13 sexually mature bulls with acquired inguinal hernias. PROCEDURES: Medical record databases of 3 veterinary teaching hospitals were searched to identify records of bulls that underwent herniorrhaphy for correction of an inguinal hernia from 2005 to 2017. Information extracted from the medical records included breed, age, duration and side of the hernia, surgical procedure details, postoperative complications, and information regarding subsequent fertility. RESULTS: All 13 bulls had a left inguinal hernia and were anesthetized and underwent herniorrhaphy via an inguinal approach. The left testicle was removed during the surgical procedure in 2 bulls. Nylon or polypropylene mesh secured with size-5 polyester suture was used to facilitate inguinal ring closure in 2 bulls. The inguinal ring was closed with size-5 or size-2 polyester suture in the remaining bulls. Postoperative complications included hernia recurrence (n = 4), excessive scrotal swelling (3), and transient radial nerve paralysis (1). Follow-up information was available for 7 bulls. All 7 bulls had impregnated cows or heifers following surgery, including 1 bull that had hernia recurrence and underwent unilateral castration during the second herniorrhaphy. CONCLUSIONS AND CLINICAL RELEVANCE: Inguinal herniorrhaphy with or without mesh was a safe and effective procedure for inguinal hernia repair in bulls and was associated with a good prognosis for subsequent fertility. However, sparing the ipsilateral testicle during the herniorrhaphy procedure might increase the risk for hernia recurrence.

Complications and outcomes of swine that underwent cesarean section for resolution of dystocia: 110 cases (2013-2018).

OBJECTIVE: To report the surgical survival of dams and piglets and follow-up survival and future breeding potential of swine that underwent cesarean section for correction of dystocia. STUDY DESIGN: Retrospective study. ANIMALS: One hundred ten client-owned, female swine. All swine included in this study were breeding stock for market pigs to be used for exhibition purposes. METHODS: Medical records of swine that underwent cesarean section at The Ohio State University Hospital for Farm Animals for resolution of dystocia between January of 2013 and July of 2018 were reviewed. Signalment, history, number of piglets per litter, treatments, and surgical procedure were recorded. Follow-up information (survival, complications, and additional pregnancies) was obtained via telephone interview. RESULTS: A fetus was not palpable in 77 of 110 (70%) cases at presentation. The median litter size was eight piglets (range, 1-14), with medians of five (range, 0-13) live and one dead (range, 0-11) piglets per litter. Follow-up was available for 52 dams, of which 39 (75%) survived. Complications were recorded in 20 of 52 (38.46%) cases and included incisional seroma formation, lethargy, and anorexia. Twenty-three dams became pregnant and farrowed after the cesarean section, with no reported complication in 13 of these. CONCLUSION: Cesarean section in swine is associated with a good prognosis for recovery from the procedure and a fair to guarded prognosis for future breeding. CLINICAL SIGNIFICANCE: Cesarean section may be considered for resolution of dystocia in swine. However, owners should be advised that nearly half of sows require assistance in subsequent deliveries.

Pharmacokinetics of an intravenous constant rate infusion of a morphine-lidocaine-ketamine combination in Holstein calves undergoing umbilical herniorrhaphy.

OBJECTIVE: To describe the pharmacokinetics of morphine, lidocaine, and ketamine associated with IV administration of a constant rate infusion (CRI) of a morphine-lidocaine-ketamine (MLK) combination to calves undergoing umbilical herniorrhaphy. ANIMALS: 20 weaned Holstein calves with umbilical hernias. PROCEDURES: Calves were randomly assigned to receive a CRI of an MLK solution (0.11 mL/kg/h; morphine, 4.8 µg/kg/h; lidocaine, 2.1 mg/kg/h; and ketamine, 0.42 mg/kg/h) for 24 hours (MLK group) or 2 doses of flunixin meglumine (1.1 mg/kg, IV, q 24 h) and a CRI of saline (0.9% NaCl) solution (0.11 mL/kg/h) for 24 hours (control group). For all calves, the CRI was begun after anesthesia induction. Blood samples were obtained immediately before and at predetermined times for 120 hours after initiation of the assigned treatment. Noncompartmental analysis was used to estimate pharmacokinetic parameters for the MLK group. RESULTS: During the CRI, steady-state serum concentrations were achieved for lidocaine and ketamine, but not morphine. Mean terminal half-life was 4.1, 0.98, and 1.55 hours and area under the concentration-time curve was 41, 14,494, and 7,426 h•µg/mL for morphine, lidocaine, and ketamine, respectively. After the CRI, the mean serum drug concentration at steady state was 6.3, 616.7, and 328 ng/mL for morphine, lidocaine, and ketamine, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: During the CRI of the MLK solution, steady-state serum concentrations were achieved for lidocaine and ketamine, but not morphine, likely owing to the fairly long half-life of morphine. Kinetic analyses of MLK infusions in cattle are necessary to establish optimal dosing protocols.

Analgesic efficacy of an intravenous constant rate infusion of a morphine-lidocaine-ketamine combination in Holstein calves undergoing umbilical herniorrhaphy.

OBJECTIVE: To assess the analgesic efficacy of an IV constant rate infusion (CRI) of a morphine-lidocaine-ketamine (MLK) combination in calves undergoing umbilical herniorrhaphy. ANIMALS: 20 weaned Holstein calves with umbilical hernias. PROCEDURES: Calves were randomly assigned to receive a CRI of an MLK solution (0.11 mL/kg/h; morphine, 4.8 µg/kg/h; lidocaine, 2.1 mg/kg/h; and ketamine, 0.42 mg/kg/h) for 24 hours (MLK group) or 2 doses of flunixin meglumine (1.1 mg/kg, IV, q 24 h) and a CRI of saline (0.9% NaCl) solution (0.11 mL/kg/h) for 24 hours (control group). The assigned CRI was begun after anesthesia induction. A pain-scoring system and incisional algometry were used to assess pain, and blood samples were obtained to measure serum cortisol concentration at predetermined times for 120 hours after CRI initiation. RESULTS: Mean pain scores did not differ significantly between the MLK and control groups at any time. Mean algometry score for the MLK group was significantly greater (calves were less responsive to pressure) than that for the control group at 4 hours after CRI initiation. Mean cortisol concentration decreased over time for both groups and was significantly greater for the MLK group than the control group at 1, 4, and 18 hours after CRI initiation. CONCLUSIONS AND CLINICAL RELEVANCE: A CRI of MLK provided adequate postoperative analgesia to calves that underwent umbilical herniorrhaphy. However, the technical support required for CRI administration limits its use to hospital settings. Kinetic analyses of MLK infusions in cattle are necessary to establish optimal dosing protocols and withdrawal intervals.

Closing wedge ostectomy with transfixation pin-cast stabilization for correction of angular limb deformities of the metatarsophalangeal region in four cattle.

CASE DESCRIPTION: 4 calves were evaluated because of lameness and an angular limb deformity of the metatarsophalangeal region. CLINICAL FINDINGS: 3 calves (ages, 5 days, 10 days, and 1 month) had a congenital varus deformity of the metatarsophalangeal region characterized by medial subluxation of the first phalanx of digits 3 and 4 at the metatarsophalangeal joints. A 6-month-old heifer had a valgus deformity of the metatarsophalangeal region secondary to a malunion of a Salter-Harris type II fracture. The degree of deformity angulation ranged from 16° to 54° for the 4 patients. TREATMENT AND OUTCOME: A closing wedge ostectomy with transfixation pin-cast application was performed on the affected limb of all 4 patients. The ostectomy healed with only minor complications (disuse osteopenia distal to the transfixation pins [n = 4] and cast sores [1]) that were easily resolved with no long-term adverse effects. Duration of follow-up for the 4 patients ranged from 6 to 17 months, and the owners reported satisfactory ambulation with no (n = 2) or only mild (2) residual lameness in the affected limb. CLINICAL RELEVANCE: Results suggested that a closing wedge ostectomy with transfixation pin-cast stabilization is an alternative for management of angular limb deformities of the metatarsophalangeal region in cattle. Such treatment improved the quality of life for all 4 patients. However, 2 of the 4 patients had congenital deformities confirmed to be heritable. There are ethical concerns associated with treating animals with heritable disorders, and exhibition and breeding of such animals should be avoided.

Investigation of a novel prosthesis technique for extracapsular stabilization of cranial cruciate ligament-deficient stifle joints in adult cattle.

OBJECTIVE: To evaluate a novel prosthesis technique for extracapsular stabilization of cranial cruciate ligament (CCL)-deficient stifle joints in adult cattle. SAMPLE: 13 cadaveric bovine stifle joint specimens. PROCEDURES: In the first of 3 study phases, the most isometric points on the distal aspect of the femur (distal femur) and proximal aspect of the tibia (proximal tibia) were determined from measurements obtained from lateromedial radiographs of a stifle joint specimen maintained at angles of 135°, 90°, 65°, and 35°. During phase 2, 800-lb-test monofilament nylon leader line was cut into 73-cm-long segments. Each segment was secured in a loop by use of 2, 3, or 4 crimping sleeves such that there were 12 replicates for each construct. Each loop was distracted to failure at a constant rate of 1 mm/s. Mean force at failure and elongation and mode of failure were compared among the 3 constructs. During phase 3, bone tunnels were created in the distal femur and proximal tibia at the isometric points identified during phase 1 in each of 12 CCL-deficient stifle joint specimens. The 3-sleeve construct was applied to each specimen. Specimens were distracted to failure at a constant rate of 1 mm/s. RESULTS: Among the 3 constructs evaluated, the 3-sleeve construct was considered optimal in terms of strength and amount of foreign material. In phase 3, all replicates failed because of suture slippage. CONCLUSIONS AND CLINICAL RELEVANCE: Use of 800-lb-test monofilament nylon leader line as a prosthesis might be a viable alternative for extracapsular stabilization of CCL-deficient stifle joints in adult cattle. Further in vivo studies are necessary.

Short- and long-term success of transfixation pin casts used to stabilize long bone fractures in ruminants.

Transfixation pin casts (TPC) may be useful in management of fractures in ruminants. A retrospective study was conducted to report the uses, complications, and outcomes of TPC in ruminant fracture stabilization. Twenty-five cattle, 7 goats, and 7 sheep with long bone fractures managed with TPC met the inclusion criteria. Long-term outcome was assessed from telephone interviews with owners. Thirty-one animals (79%) survived to removal of external coaptation and return to the farm. Common complications included pin-hole osteitis and disuse osteopenia. Common complications resulting in death or euthanasia included osteomyelitis and non-union and pin tract fracture. Animals with increased body weight had a greater odds of dying or being euthanized. Cattle had a decreased odds of dying or being euthanized compared with goats and sheep. Long-term follow-up was available for 20 patients, 17 of which returned to intended use and 12 of which had no residual lameness.

Succès à court et à long terme des plâtres à broche transfixiante utilisés pour stabiliser les fractures d'os longs chez les ruminants. Les plâtres à broche transfixiante (PBT) peuvent être un outil utile pour la gestion des fractures des ruminants. Une étude rétrospective a été réalisée afin de faire rapport sur les utilisations, les complications et les résultats des PBT pour la stabilisation des fractures des ruminants. Vingt-cinq bovins, 7 chèvres et 7 moutons avec des fractures d'os longs gérée par PBT ont satisfait aux critères d'inclusion. Les résultats à long terme ont été évalués par entrevue téléphonique avec les propriétaires. Trente-et-un (79 %) animaux ont survécu à l'enlèvement de la coaptation externe et sont retournés à la ferme. Les complications communes incluaient l'ostéite du trou de la broche et l'ostéopénie par inaction. Les complications communes se traduisant par la mort ou l'euthanasie incluaient l'ostéomyélite, la non-union et la fracture causée par la broche. Les animaux ayant un poids supérieur présentaient plus de risques de mortalité ou d'euthanasie. Les bovins présentaient des risques réduits de mortalité ou d'euthanasie comparativement aux chèvres et aux moutons. Le suivi à long terme était disponible pour 20 patients et 17 d'entre eux sont retournés à leur usage prévu et 12 n'avaient pas de boiterie résiduelle.(Traduit par Isabelle Vallières).

Pharmacokinetics of ampicillin-sulbactam in serum and synovial fluid samples following regional intravenous perfusion in the distal portion of a hind limb of adult cattle.

OBJECTIVE To describe concentration-over-time data for ampicillin and sulbactam in the digital and systemic circulations and synovial fluid (SYN) of cattle following a single injection of ampicillin-sulbactam as a regional IV perfusion (RIVP). ANIMALS 6 healthy adult nonlactating Jersey-crossbred cows. PROCEDURES The right hind limb of each cow was aseptically prepared. A tourniquet was applied around the midmetatarsal region, and 1.0 g of ampicillin with 0.5 g of sulbactam in a combined formulation was administered as an RIVP into the dorsal common digital vein (DCDV). Blood samples from the DCDV and jugular vein and SYN samples from the metatarsophalangeal joint of the prepared limb were collected immediately before and at predetermined times for 24 hours after RIVP. One blood sample was obtained from the abaxial proper plantar vein of the lateral digit of the prepared limb 0.25 hours after RIVP. Serum and SYN ampicillin and sulbactam concentrations were determined by high-performance liquid chromatography. RESULTS Mean ± SD maximum concentration of ampicillin in SYN and serum obtained from the abaxial proper plantar and jugular veins was 1,995 ± 1,011 µg/mL, 5,422 ± 1,953 µg/mL, and 2.5 ± 1.6 µg/mL, respectively. Corresponding serum and SYN concentrations of sulbactam were lower but followed the same pattern over time as those for ampicillin. Synovial fluid ampicillin concentration remained above 8 µg/mL for a mean time of 18.9 hours. CONCLUSIONS AND CLINICAL RELEVANCE Potentially therapeutic concentrations of ampicillin were achieved in regional serum and SYN samples; SYN concentrations remained at potentially therapeutic values for > 12 hours following RIVP of 1.5 g of ampicillin-sulbactam in the hind limb of healthy cows.

Surgery of the Forestomach.

Indications for rumen surgery include rumen tympany (bloat), toxic plant ingestion, to provide enteral nutrition, to perform elective cannula placement, and to access other forestomach compartments (reticulum/omasum). The rumen is a highly contaminated viscus and special care should be taken to avoid peritoneal contamination from rumen contents. Diseases causing forestomach dysfunction and surgical procedures on the forestomach compartments are discussed here.

Surgical Management of Fractures and Tendons.

Long bone fractures and disorders of tendons and ligaments represent a significant proportion of surgical orthopedic cases presented to ruminant veterinarians. The presentation of these patients, their diagnostic work-up, surgical treatment, and expected outcome will be discussed. The outcome of these cases depends largely on the presenting problem; however, accurate diagnosis and prompt surgical intervention can greatly improve the outcome of many of these cases.

Surgical Management of Abomasal Disease.

Abomasal diseases are common in cattle. Many of these diseases can be managed surgically. This article briefly discusses the various surgical diseases affecting the abomasum. The pathogenesis, surgical procedures, and prognosis are reviewed. Abomasal displacements in cattle are a focus, because surgical correction of these conditions represents the bulk of abomasal surgeries in ruminants. Surgical principles of conventional surgery as well as minimally invasive techniques for correction of abomasal displacements are discussed. The surgical management of other abomasal diseases such as intraluminal abomasal obstructions and abomasal ulcers are also reviewed.

Indications for and factors relating to outcome after rumenotomy or rumenostomy in cattle: 95 cases (1999-2011).

OBJECTIVE: To evaluate indications for and factors relating to outcome after rumenotomy or rumenostomy in cattle. DESIGN: Retrospective case series. ANIMALS: 95 cattle that underwent rumenotomy or rumenostomy. PROCEDURES: Medical records for 95 cattle that underwent either rumenostomy or rumenotomy at 2 veterinary teaching hospitals in 1999 through 2011 were analyzed. Reasons for the procedures were noted. Long-term outcome was determined during telephone interviews with owners. RESULTS: 42 (44%) bovids underwent rumenostomy and 53 (56%) bovids underwent rumenotomy. Among the 42 animals undergoing rumenostomy, 18 (43%) had rumen cannulas placed during elective procedures. Other indications for rumenostomy included ruminal tympany (bloat [n = 20]), esophageal obstruction (choke [1]), grain overload (1), and provision of access for administration of enteral nutrition (2). Indications for rumenotomy included traumatic reticuloperitonitis (n = 31), bloat (9), foreign body (6), choke (5), and other (2). Long-term follow-up data were available for 31 of 42 (74%) bovids that underwent rumenostomy. Of those 31 animals, 17 (55%) were still in the herd, 4 (13%) had been culled, and 10 (32%) had died or were euthanized. Long-term follow-up data were available for 38 of 53 (72%) bovids that underwent rumenotomy. Of those 38 animals, 13 (34%) were still in the herd, 14 (37%) had been culled, and 11 (29%) had died or been euthanized. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that rumenotomy and rumenostomy can be effective in treating or relieving complications secondary to forestomach disorders in cattle. Bovids undergoing rumen surgery had a favorable prognosis for survival and a fair prognosis for potential return to production.

Absorption and disposition of florfenicol after intravenous, intramuscular and subcutaneous dosing in alpacas.

The objectives of this study were to define disposition and systemic availability of florfenicol in alpacas. Administration of 20 mg/kg doses to 8 male alpacas by i.v., i.m. and s.c. routes was performed by randomized, 3-way crossover design. Clearance and steady state volumes (Vdss) after i.v. injection were 5 ml/min/kg and 775 ml/kg respectively. Mean residence time (MRT) and terminal phase half-life (T1/2λz) were 2.8 h and 2 h respectively. Maximum serum concentrations (Cmax) after i.m. were higher than s.c. administration (p = 0.034). After s.c. dosing, T1/2λz and MRT were greater than after i.m. injection (p < 0.001; p = 0.006 respectively). Mean absorption time (MAT) after s.c. dosing was also prolonged (p = 0.006). Fractional absorption of florfenicol after i.m. and s.c. was not different (p > 0.05). Serum florfenicol concentrations remained >1.0 µg/ml for 20 h after i.m. dosing. Differences in rate and extent of florfenicol absorption after extravascular dosing could influence therapeutic outcomes.

Characterization of the contributions of Hp-MMP 9 to the serum acute phase protein response of lipopolysaccharide challenged calves.

BACKGROUND: Bovine respiratory disease (BRD) is a costly feature of modern cattle production. Early and accurate detection of BRD may prove useful in the successful management of this disease. The primary objective of the study was to define the time course of covalent complexes of neutrophil, haptoglobin (Hp) and matrix metalloproteinase 9 (Hp-MMP 9) in serum after intravenous lipopolysaccharide (LPS) in comparison to traditional markers. Our hypothesis was that serum concentrations of neutrophil Hp-MMP 9 provides information distinct from traditional acute phase protein markers. To characterize the neutrophil responses to lipopolysaccharide (E. coli; O111:B4; 2.5 µg/kg body weight), nine healthy, Jersey calves (65-82 days of age; 74.5 ± 13.1 kg) were challenged and physiologic parameters, peripheral blood cell counts and serum cortisol (C), Hp-MMP 9, Hp, alpha1-acid glycoprotein (AGP), serum amyloid A (SAA) were obtained starting 24 hours before to 96 hours post-LPS challenge. RESULTS: Physiologic parameters (temperature, pulse, respiratory rate) and attitude assessed at each time point indicated that LPS challenge resulted in rapid onset of depression, tachypnea, leukopenia, neutropenia and lymphopenia within 1 hour. Serum C concentrations were significantly increased by 1 hour post-LPS. Serum Hp-MMP 9 complexes were detectable in serum by 0.5 hours and peaked at 16 h, serum total Hp remained <10 µg/mL until 8 hours post LPS infusion and were significantly greater than baseline by 12 hours post-LPS infusion. Serum amyloid A concentrations increased significantly by 8 hours post LPS. Serum concentrations of AGP increased significantly by 16 hours post LPS. Serum concentrations of Hp, SAA and AGP remained significantly greater than baseline out to 96 hours post-LPS. The total systemic exposure to traditional makers is significantly greater than from Hp-MMP 9 CONCLUSION: Using a well described model for acute phase protein responses, the data demonstrate that serum neutrophil Hp-MMP 9 complexes appear sooner and decline more rapidly than other acute phase proteins (APP). Since Hp-MMP9 is stored pre-formed, it provides information specifically addressing the LPS-induced activation of bovine neutrophils. Contributions of Hp-MMP 9 to the serum acute phase protein response may provide useful information, independent of hepatic responses, in diagnosis of acute inflammation.