The use of circular and hybrid external skeletal fixation systems to repair open tibial fractures in large ruminants: a report of six clinical cases.

A prospective clinical study consisting of six bovines (200-300 kg body weight) undergoing open tibial fractures was carried out, to evaluate the use of circular and hybrid external skeletal fixation (ESF) systems for open tibial fracture repair in large ruminants. The ESF systems consisting of 4 full rings (n = 2), 8 half-rings (n = 1), 2 full rings with 2 sidebars (n = 2) or 2 full rings with 4 sidebars (n = 1) were used to treat open tibial fractures. The healing progress of the animals was evaluated based on different clinical and radiographic examinations. The level of fracture reduction, alignment, and fixation ranged between satisfactory to adequate in all the animals. The fixators were well tolerated and maintained by the animals till the complete repair of the fracture. Adequate fracture healing with satisfactory functional recovery was observed in all the animals in about 3-4 months. The different designs of ESFs were found to provide adequate stability in open tibial fractures in animals weighing 200-300 kg. However, the fixators need to be evaluated in numerous clinical cases to establish their suitability in routine clinical settings.

Decellularized xenogenic bone graft for repair of segmental bone defect in rabbits.

Background: Bone grafting is a preferred treatment option for the healing of large diaphyseal bone defects and is useful in the management of nonunion, delayed union, and tumor resection. Aims: To investigate a decellularization protocol of bovine cancellous bone for xenogenic implantation in radial bone defects in rabbits. Methods: Bovine bone scaffolds fabricated with various decellularization protocols viz phosphate buffer saline (PBS), 1% sodium dodecyl sulfate (SDS), and rapid freeze and thaw technique. The manufactured scaffolds were characterized by biomechanical testing, histological staining, and scanning electron microscopy. A 10 mm rabbit radius bone defect was repaired with autograft and SDS treated and rapid freeze and thaw in groups A, B, and C respectively. Healing was evaluated by radiography and histopathology at 0, 30, 60, and 90 days. The grafts were also checked for host tissue reaction and incorporation into the defect. Results: The freeze and thaw group showed complete elimination of all cellular nuclei, regular arrangement of collagen fiber, and no significant difference in tensile strength compared to 1% SDS treated and native groups. The in vivo radiographic and histopathological study showed that the rapid freeze and thaw group had complete bridging of the bone gap defect with new bone formation and they were immunologically less reactive compared to group B. Conclusion: The in vitro and in vivo evaluation of the grafts suggested that freeze and thaw technique was most superior to all other techniques for effective decellularization and augmentation of bone healing with better integration of the graft into the host.

Use of locking plate in combination with dynamic compression plate for repair of tibial fracture in a young horse.

Grade 1 open spiral fracture of left tibia in a 1.5 year-old horse was treated using a combination of 4.5 mm locking compression plate (LCP) and a dynamic compression plate applied in a neutralization manner. The open wound was managed postoperatively by regular dressing and lavage. Radiograph at 24 days post-treatment revealed callus formation and at two months complete bridging callus was observed. At the end of six months complete healing of the fracture with functional recovery of the limb was observed.

Evaluation of tissue-engineered bone constructs using rabbit fetal osteoblasts on acellular bovine cancellous bone matrix.

AIM: The aim of this study was to generate composite bone graft and investigate the rabbit fetal osteoblasts adhesion, proliferation and penetration on acellular matrices of cancellous bone. MATERIALS AND METHODS: Acellular cancellous bone was prepared and developed as in the previous study with little modification. These matrices were decellularized by rapid freeze and thaw cycle. To remove the cell debris, they were then treated with hydrogen peroxide (3%) and ethanol to remove antigenic cellular and nuclear materials from the scaffold. Primary osteoblast cells were harvested from 20 to 22 days old rabbit fetal long and calvarial bone. These cells were cultured and characterized using a specific marker. The third passaged fetal osteoblast cells were then seeded on the scaffold and incubated for 14 days. The growth pattern of the cells was observed. Scanning electron microscope and hematoxylin and eosin staining were used to investigate cells proliferation. RESULTS: The cells were found to be growing well on the surface of the scaffold and were also present in good numbers with the matrix filopodial extensions upto inside of the core of the tissue. CONCLUSION: Thus, a viable composite scaffold of bone could be developed which has a great potential in the field of bone tissue engineering.

Cartilage tissue engineering: Role of mesenchymal stem cells along with growth factors & scaffolds.

Articular cartilage injury poses a major challenge for both the patient and orthopaedician. Articular cartilage defects once formed do not regenerate spontaneously, rather replaced by fibrocartilage which is weaker in mechanical competence than the normal hyaline cartilage. Mesenchymal stem cells (MSCs) along with different growth factors and scaffolds are currently incorporated in tissue engineering to overcome the deficiencies associated with currently available surgical methods and to facilitate cartilage healing. MSCs, being readily available with a potential to differentiate into chondrocytes which are enhanced by the application of different growth factors, are considered for effective repair of articular cartilage after injury. However, therapeutic application of MSCs and growth factors for cartilage repair remains in its infancy, with no comparative clinical study to that of the other surgical techniques. The present review covers the role of MSCs, growth factors and scaffolds for the repair of articular cartilage injury.

In vitro biomechanical testing of different configurations of acrylic external skeletal fixator constructs.

OBJECTIVE: To evaluate the in vitro biomechanical properties of four different configurations of acrylic external skeletal fixator constructs. MATERIALS AND METHODS: Simulated bone constructs were prepared using two segments of 20 mm ultra-high-density polyethylene rods with a gap of 5 mm. The full pins (1.5 mm) were passed through the proximal and distal segments of ultra-high-density polyethylene rods, in the same plane, parallel to each other in configuration U, and were crossed in the M1, M2 and C configurations at a 90° angle to each other. Configuration U was a single bilateral uniplanar construct, M1 was a double orthogonal bilateral construct, M2 was a double orthogonal bilateral construct with proximal and distal connecting articulations, and C was a double orthogonal bilateral construct with proximal and distal circumferential articulations. Temporary scaffolds of different external skeletal fixator configurations were constructed using commercially available polyvinyl chloride pipes (20 mm) connected and secured to the fixation pins at a fixed distance from the rods. Acrylic powder (polymer) mixed with liquid (monomer) was poured into the pipes and allowed to solidify to form the side bars and rings. The external skeletal fixator constructs were then subjected to axial compression, cranio-caudal three-point bending and torsion (n = 4 each) using a universal testing machine. Mechanical parameters, namely stress, strain, modulus of elasticity, stiffness and bending moment of fixator constructs, were determined from load-displacement curves. RESULTS: Configuration U was the weakest and configuration C was the strongest under all the testing modes. Under compression, the M1, M2 and C configurations were similar. Under bending, a significant difference was observed among the uniplanar, multiplanar and circular configurations with no difference between M1 and M2. However, under torsion, all the external skeletal fixator configurations differed significantly. CLINICAL SIGNIFICANCE: The freeform external skeletal fixator using acrylic as a replacement for a metallic bar may be useful to treat bone fractures and luxations in small animals, as it is mechanically strong, lightweight, economical, and pins can be passed from any direction depending upon the clinical situation.

An in vitro biomechanical investigation of an interlocking nail system developed for buffalo tibia.

OBJECTIVE: The objectives of the study were to determine the mechanical properties of a customized buffalo interlocking nail (BIN), intact buffalo tibia, and ostectomized tibia stabilized with BIN in different configurations, as well as to assess the convenience of interlocking nailing in buffalo tibia. MATERIALS AND METHODS: The BIN (316L stainless steel, 12 mm diameter, 250 mm long, nine-hole solid nails with 10° proximal bend) alone was loaded in compression and three-point bending (n=4 each); intact tibiae and ostectomized tibiae (of buffaloes aged 5-8 years, weighing 300-350 kg) stabilized with BIN using 4.9 mm standard or modified locking bolts (4 or 8) in different configurations were subjected to axial compression, cranio-caudal three-point bending and torsion (n=4 each) using a universal testing machine. Mechanical parameters were determined from load-displacement curves and compared using Kruskal-Wallis test (p<0.05). RESULTS: Intact tibiae were significantly stronger than BIN and bone-BIN constructs in all testing modes. The strength of fixation constructs with eight locking bolts was significantly more than with four bolts. Overall strength of fixation with modified locking bolts was better than standard bolts. Based on technical ease and biomechanical properties, cranio-caudal insertion of bolts into the bone was found better than medio-lateral insertion. CLINICAL SIGNIFICANCE: The eight bolt BIN-bone constructs could be useful to treat tibial fractures in large ruminants, especially buffaloes.

Comparison of autogenic and allogenic bone marrow derived mesenchymal stem cells for repair of segmental bone defects in rabbits.

Autogenic and allogenic bone marrow derived mesenchymal stem cells (BM-MSCs) were compared for repair of bone gap defect in rabbits. BM-MSCs were isolated from bone marrow aspirates and cultured in vitro for allogenic and autogenic transplantation. A 5mm segmental defect was created in mid-diaphysis of the radius bone. The defect was filled with hydroxyapatite alone, hydroxyapatite with autogeneic BM-MSCs and hydroxyapatite with allogenic BM-MSCs in groups A, B and C, respectively. On an average 3.45×10(6) cells were implanted at each defect site. Complete bridging of bone gap with newly formed bone was faster in both treatment groups as compared to control group. Histologically, increased osteogenesis, early and better reorganization of cancellous bone and more bone marrow formation were discernible in treatment groups as compared to control group. It was concluded that in vitro culture expanded allogenic and autogenic BM-MSCs induce similar, but faster and better healing as compared to control.

Comparative evaluation of halothane anaesthesia in medetomidine-butorphanol and midazolam-butorphanol premedicated water buffaloes (Bubalus bubalis).

Six clinically healthy male water buffaloes (Bubalus bubalis) 2-3 years of age and weighing 290-325 kg were used for 2 different treatments (H1 and H2). The animals of group H1 were premedicated with medetomidine (2.5 g/kg,i.v.) and butorphanol (0.05 mg/kg, i.v.), while in group H2 midazolam (0.25 mg/kg) and butorphanol (0.05 mg/kg) were used intravenously. Induction of anaesthesia was achieved by 5% thiopental sodium in H1 (3.85 +/- 0.63 mg/kg) and H2 (6.96 +/- 0.45 mg/kg) groups. The anaesthesia was maintained with halothane in 100 % oxygen through a large animal anaesthetic machine. Better analgesia and sedation with a significantly lower dose of thiopental for induction and significantly higher values of sternal recumbency time and standing time were recorded in group H1 than in group H2, whereas no significant (P > 0.05) difference for the halothane concentration was observed between groups H1 and H2. Significant decrease in heart rate was observed in group H1 whereas it significantly increased in group H2. In both groups, RR decreased during the preanaesthetic period, which increased significantly (P < 0.01) after halothane administration. In both groups a significant (P < 0.01) fallin RT was recorded from 20 min to the end of observation period. A significant (P < 0.05) fall in MAP was observed in group H1 from 15 min until the end, while in group H2 MAP increased nonsignificantly (P > 0.05) after premedication and a significant (P < 0.05) occurredafter thiopental administration. In both groups a significant (P < 0.01) increase in CVP and a significant (P < 0.01) decrease in SpO2 were observed after premedication which persisted up to 120 min. ECG changes included significant (P < 0.01) decrease and increase in QRS amplitudes in groups H1 and H2 respectively, a significant (P < 0.05) increase in PR interval was recorded at 15 min in group H1, a significant (P < 0.05) decrease in PR interval in group H2, a significant (P < 0.05) decrease in T wave amplitude in group H1, and a significant (P < 0.01) increase in duration of T wave in group H1 . It is concluded that both combinations can be used safely in buffaloes for surgery of 2 h duration but better sedation, analgesia and muscular relaxation and more dose sparing effect on anaesthetics and shorter recovery times were observed in group H1.

Evaluation of autologous bone marrow-derived nucleated cells for healing of full-thickness skin wounds in rabbits.

The aim of the study was to evaluate the potential of autologous bone marrow-derived nucleated cells to enhance the rate of healing of full-thickness excisional skin wounds in rabbits. The study was conducted on 20 New Zealand white rabbits of either sex. Two, 2 x 2 cm full-thickness skin (thoracolumabar region) excisional wounds were created; one on each side of the dorsal midline in each animal. The wounds were randomly assigned to either injection of autologous bone marrow-derived nucleated cells into the wound margins (BI), or topical application of sterile saline solution (normal saline, NS), which served as control. The wound healing was assessed by evaluation of granulation tissue formation, wound contraction, epithelisation and histopathological and histochemical changes up to 28 days after creation of the wound. Granulation tissue appeared significantly faster in BI-treated wounds (3.22 +/- 0.22 days) than in NS-treated wounds (4.56 +/- 0.47 days). Better epithelisation was seen histologically in BI wounds than in NS-treated wounds. Wound contraction was significantly more in BI wounds when compared with NS wounds on 21 post-surgery. Histopathological examination of the healing tissue showed early disappearance of inflammatory reaction, significantly more neovascularisation, and more fibroplasias and early lay down and histological maturation of collagen in BI wounds than in control wounds. It was concluded that injection of autologous bone marrow-derived nucleated cells in the wound margins induced faster and better quality healing of excisional skin wounds in rabbits when compared with normal saline. The injection of autologous bone marrow-derived nucleated cells can be used to promote healing of large full-thickness skin wounds in rabbits.

Autologous bone marrow-derived cells for healing excisional dermal wounds of rabbits.

The wound-healing potential of autologous bone marrow-derived nucleated cells was evaluated in full-thickness skin wounds in the thoracolumbar region of 20 clinically healthy rabbits. Three wounds of 2 x 2 cm, one on the left side and two right of the midline, were created on the dorsal lumbar region of each rabbit under xylazine-ketamine anaesthesia. The wounds of each animal were randomly assigned to one of three treatments: injection of autologous bone marrow-derived cells into wound margins (BI), topical application of bone marrow-derived cells over the wound surface (BT) or 5 per cent povidone iodine solution (PI) (control). Wounds were observed for 28 days for granulation tissue formation, wound contraction, histomorphological and histochemical evaluation, and time to complete healing. The mean (se) time to appearance of granulation tissue was significantly less in BI-treated wounds (3.22 [0.22] days) than the BT-treated (3.89 [0.40] days) and PI-treated (4.89 [0.47] days) groups. On days 14 and 21 after surgery, wound contraction was significantly (P<0.05) higher in BI-treated wounds (73.00 and 97.35 per cent) than in those treated with BT (58.75 and 84.87 per cent) and PI (54.84 and 84.60 per cent). Histomorphological findings showed an earlier disappearance of inflammatory reaction, better epithelialisation, significantly more neovascularisation, more fibroplasia and collagenation, and earlier histological maturation in BI- and BT-treated wounds than in control wounds.

Determinants of bone mass, density and growth in growing dogs with normal and osteopenic bones.

Survey radiographs of all the growing dogs aged up to 6 months, which were presented to the IVRI polyclinics during the 10 year period were screened to study the determinants of bone mass, density and growth. On the basis of clinical history and radiographic evaluation of long bones, the cases were categorizes as normal or osteopenic. The relative cortical density (RCD), cortical index (CI), diameter of bone at the distal metaphysis (DDFM) and the width of the growth plate (WFGP) were determined by taking the femur as a model bone in German shepherd, Doberman and Spitz breeds of dogs at different age groups. The results showed that RCD was the least in 0-2 month old normal growing dogs in all the breeds. As the age advanced up to 6 months the RCD increased 20-25% and at 6 months, Spitz and Doberman showed significant increase (P<0.05) in the RCD. In osteopenic bones, RCD remained less (25-50%) than that of normal animals at all age groups, and at 2-6 months of age, RCD in osteopenic bones was significantly lesser than in normal animals in GSD and Spitz breeds. The CI was also the least at 0-2 months of age in normal dogs. The CI increased about 50% at 4-6 months of age in GSD and Spitz. Whereas in Dob., there was no appreciable change in the CI at different age groups, and at 2-6 months it was significantly (P<0.05) lesser than that of Spitz. In osteopenic bones, the CI was 25-75% lesser than that of normal animals at different age groups, and at 4-6 months there was significant difference (P<0.05) between the normal and osteopenic bones in GSD and Spitz. The DDFM was the least in 0-2 month old normal growing dogs, and as the age advanced, it increased 10-20% up to 6 months. However, no significant difference in the DDFM was seen between breeds and also between the normal and osteopenic bones at different age groups. In normal animals, the WFGP was the highest in the early age, subsequently it reduced 50-75% and at the 4-6 months there was a significant decrease (P<0.05) in all breeds of dogs. And at the 4-6 months, there was significant (P<0.05) difference in the WFGP between breeds, it was the least in Spitz and maximum in Dob., suggesting faster growth plate closure in Spitz than in GSD and Dob. breeds. In osteopenic bones, WFGP was generally more than in normal animals, and at 4-6 months (about 3-5 times more) there was significant difference (p<0.05) between the normal and osteopenic bones in all breeds, indicating that physeal closure may be delayed in osteopenic bones. The results indicate that among different breeds Doberman breed has the least bone mass and may be more prone to osteopenia; whereas Spitz has the strongest bone.

Effects of Nandrolone and TGF-beta1 in growing rabbits with osteopenia induced by over-supplementation of calcium and vitamin D3.

The study was undertaken to find out the effects of over supplementation of dietary calcium and vitamin D3 on the mineralization of growing skeleton, taking rabbit as an animal model; further to study the effects of Nandrolone deconoate and TGF-beta1 on the mineralization of osteopenic bones. Twenty four New Zealand White rabbits of either sex, 60 day old, were randomly divided in 4 equal groups, A, B, C and D. The animals of groups B, C and D were administered with oral supplementation of calcium (2000 mg/kg of standard rabbit feed) and vit-D3 (1000 IU/kg of standard feed) for 60 days. The animals of group A were given standard ration without any supplementation. After 60 days, the Ca-vit.D3 supplementation was discontinued; and the animals of group C were administered with TGF-beta1 (10 ng, i.m.) once in every three days and animals of group D were given Nandrolone deconoate (10 mg, i.m.) once every week for 30 days, whereas in animals of group B, no treatment was given. All the animals were evaluated based on different observations like body weight, radiographic observations, circulating biochemical and hormone profile (plasma Ca, IP, AP, OC and iPTH) every 15 days up to 60 days after initiation of treatment. The results indicated that the body weight of rabbits in different groups increased gradually and steadily at different intervals till the end of observation period, however, the increase was non-significantly more in group D. The CI in group A increased gradually at different intervals; whereas in groups B, C and D, there was no appreciable increase in the CI during the period of Ca-vit.D3 supplementation, suggesting development of osteopenia. Treatment with TGF-beta1 did not increase the CI significantly, whereas Nandrolone treatment resulted in significant increase in the CI on days 45 and 60. The plasma Ca levels showed slight but gradual increase from day 0 to 60 in almost all groups. Subsequently also, there was no marked change at different intervals in groups A and B; however, significant reduction in plasma Ca was noticed in group C on 15(th) day and in group D on 60(th) day after initiation of treatment. Plasma IP levels in groups B and C showed a decreasing trend up to day 60. After discontinuation of Ca-vit.D3 supplementation, in group B, it further decreased to remain significantly lower on 15(th) day, and in groups C and D, it increased significantly on 60(th) post-treatment day. There was no significant change in the AP activity during the entire period of study in group A; whereas significant reduction in AP activity was measured on 30(th) and 60(th) days of treatment in groups B and C, and on 15(th) day of treatment in group D. Plasma iPTH values did not show any significant change at any interval during the first 60 days in all groups. On 30(th) and 60(th) days of treatment, the mean iPTH level remained significantly lesser in group B. In all groups treated with over supplementation of Ca and vit.D3, there was a non-significant increase in the plasma OC levels up to day 60; however, there was no significant difference between the groups. It can be concluded that additional supplementation of Ca and vit.D3 results in osteopenia in growing rabbits. Administration of Nandrolone helps to increase the mineral density in osteopenic bones, whereas TGF-beta1 does not seem to have positive effect on the skeletal mineralization.

Occurrence and pattern of long bone fractures in growing dogs with normal and osteopenic bones.

A retrospective study was undertaken to record the occurrence and pattern of long bone fractures, and the efficacy of Intramedullary (IM) Steinmann pin fixing in growing dogs. All the records of growing dogs during a 10-year-period were screened to record the cause of trauma, the age and sex of the animal, the bone involved, the type and location of the fracture, the status of fixation, alignment, maintenance of fixation and fracture healing. The results were analysed and comparisons were made between growing dogs with normal and osteopenic bones. Among the 310 cases of fractures recorded, the bones were osteopenic in 91 cases (29%). Minor trauma was the principal cause of fracture in dogs with osteopenia (25%), and indigenous breeds were most commonly affected (38%). Fractures in dogs with osteopenic bones were most commonly recorded in the age group of 2-4 months (53%), whereas fractures in normal dogs were almost equally distributed between 2 and 8 months of age. Male dogs were affected significantly more often in both groups. In osteopenic bones, most fractures were recorded in the femur (56%), and they were distributed equally along the length of the bone. Whereas in normal bones, fractures were almost equally distributed in radius/ulna, femur and tibia, and were more often recorded at the middle and distal third of long bones. Oblique fractures were most common in both groups; however, comminuted fractures were more frequent in normal bones, whereas incomplete fractures were more common in osteopenic bones. Ninety-nine fracture cases treated with IM pinning (66 normal, 33 osteopenic) were evaluated for the status of fracture reduction and healing. In a majority of the cases (61%) with osteopenic bones, the diameter of the pin was relatively smaller than the diameter of the medullary cavity (<70-75%), whereas in 68% of the cases in normal bones the pin diameter was optimum. The status of fracture fixing was satisfactory to good in significantly more osteonormal (59%) than osteopenic dogs (42%). Fracture healing, however, was satisfactory in significantly more cases with osteopenic than normal bones. The appearance of callus was relatively early and the amount of bridging callus was relatively large in greater number of osteopenic bone fractures. Mal-union and non-union were recorded more often in osteopenic cases than in normal cases. However, the incidence of bone shortening and osteomyelitis was significantly higher in normal bones than in osteopenic bones.

Management of fractures near the carpal joint of two calves by transarticular fixation with a circular external fixator.

A four-ring circular external skeletal fixation device was evaluated for transcarpal fixation of compound fractures in two calves. Case 1 was an eight-month-old female Holstein-Friesian x indigenous breed calf weighing 72 kg, which had a Salter-Harris type II fracture at the distal metaphysis of the right radius/ulna with an open contaminated wound on the medial aspect of the carpus. Case 2 was an 18-month-old crossbred Haryana heifer weighing 105 kg, which had a comminuted fracture at the proximal end of its left metacarpus with severe soft tissue trauma and an open wound on the medial aspect. In both cases, the fractures were repaired with four-ring circular fixators by fixing the proximal two rings in the distal radius/ulna and the distal two rings in the metacarpus. Postoperatively, both calves were treated with analgesic and anti-inflammatory drugs and antibiotic, and the pin-bone interfaces and the open wound were cleaned regularly with povidone-iodine solution. In both animals weight bearing was good to excellent in the immediate postoperative period. The fixator was well maintained and tolerated by the animals until the fractures healed after 45 to 60 days. The movement of the carpal joint was slightly affected when the fixator was removed on day 60, but a follow-up examination after one year showed that both calves had normal functional usage of the limbs.

Comparison of two doses of ropivacaine for lumbosacral epidural analgesia in buffalo calves (Bubalus bubalis).

Six male buffalo calves aged from six to eight months and weighing 100 to 120 kg were used to evaluate the efficacy and safety of caudal epidural analgesia produced by doses of 37.5 mg (5 ml) and 75 mg (10 ml) ropivacaine (0.75 per cent). The study was completed in two phases. In phase 1, all the animals were used twice to evaluate the analgesic and clinical effects of two doses of ropivacaine. In phase 2, the animals were divided into two groups of three to evaluate the effects of two doses of ropivacaine on some haemodynamic and acid-base parameters. Signs of analgesia, as evidenced by a loss of response to pinprick stimulation, were recorded only at the tail, perineum and hindlimbs of the animals given 5 ml ropivacaine, but they extended from the tail to the thorax (T9) in the animals given 10 ml ropivacaine. The duration of analgesia was five to six hours in the animals given 5 ml ropivacaine and seven to eight hours in the animals given 10 ml ropivacaine. Animals of both groups became recumbent, but the score for ataxia was higher in the animals given 10 ml ropivacaine. The respiratory rate decreased significantly (P<0.05) below the baseline in the animals given 10 ml ropivacaine, but the rectal temperature, heart rate, mean arterial pressure, central venous pressure and acid-base and electrolyte parameters did not change significantly in either group.

Clinicophysiological effects of spinally administered ketamine and its combination with xylazine and medetomidine in healthy goats.

The study was conducted in 9 healthy adult goats of either sex, weighing 15-20 kg, to evaluate and compare the clinicophysiological effects of spinally administered ketamine alone and in combination with xylazine and medetomidine. Nine trials each of the three treatments were conducted randomly by injecting ketamine (2.5 mg/kg) (n = 9), ketamine and xylazine (2.5 mg/kg and 0.05 mg/kg) (n = 9) and ketamine and medetomidine (2.5 mg/kg and 10 microg/kg) (n = 9). The drugs were administered at the lumbosacral subarachnoid space under strict aseptic conditions. The treatments were evaluated on the basis of clinicophysiological, haematological, biochemical and haemodynamic observations. Ketamine produced mild to moderate analgesia of the hindquarters. Its combination with either xylazine or medetomidine produced complete analgesia of the hindquarters for 45-60 min. Ataxia was moderate in the ketamine group, whereas animals attained sternal recumbency in the combination groups. A moderate degree of sedation was recorded in the combination groups. Heart rate and respiratory rate depression in the combination groups and heart rate and respiratory rate stimulation in ketamine group were recorded. Haematological parameters decreased in all the groups. Increase in serum glucose, creatinine and urea nitrogen was recorded in all the groups. Serum electrolytes did not show any significant change. The results showed that the combination of ketamine with xylazine or medetomidine at these dose rates produced a comparable degrees of analgesia of hindquarters with transient and minimal cardiopulmonary side effects.

Effects of epidural ketamine-xylazine combination on the clinicophysiological and haematobiochemical parameters of uraemic and healthy goats.

Xylazine-ketamine combination was evaluated for its efficacy and safety after epidural administration in uraemic and healthy goats. The combination (xylazine 0.025 mg/kg and ketamine 2.5 mg/kg) was administered to uraemic (n = 6) and healthy (n = 6) animals in the lumbosacral epidural space. The combination was evaluated in terms of clinical, physiological, haematological and biochemical parameters. The onset of analgesia was faster in healthy animals than in uraemic animals. Xylazine and ketamine produced complete analgesia of tail, perineum, inguinal and thigh regions in all animals of both groups. However, healthy animals showed longer duration of complete analgesia than did uraemic animals. Greater ataxia was recorded in healthy animals than in uraemic animals. The heart rate showed a significant decrease in both groups; however, respiratory rate and rectal temperature did not show any significant changes. Haemoglobin, packed cell volume and total leukocyte count decreased non-significantly in both groups. Total leukocyte count was significantly higher in uraemic animals. A significantly higher value of urea nitrogen and creatinine was recorded in uraemic animals. The blood electrolytes (Na+, K+ and Cl-) and blood gases (PO2 and PCO2) did not show any significant changes in both groups; however, base excess was significantly higher in uraemic animals. The effects produced by the combination on different systems were transient and values normal as the effect of the drugs wore off. The results suggest that the combination when used epidurally in uraemic goats produced effective and safe surgical analgesia.

Xylazine, ketamine and their combination for lumbar epidural analgesia in water buffalo calves (Bubalus bubalis).

The study was conducted to evaluate the effects of xylazine individually (0.05 mg/kg), ketamine individually (2.5 mg/kg), and a combination of xylazine and ketamine (0.05 mg/kg and 2.5 mg/kg) after lumbar epidural administration in water buffalo calves. Fifteen non-descript, male water buffalo calves of 6-8 months of age weighing between 55 and 75 kg were randomly placed in three groups (groups A, B and C). The agents were administered at the first lumbar epidural space. Clinico-physiological parameters, such as analgesia, ataxia, sedation, salivation, heart rate, respiratory rate and rectal temperature were studied. Other haematological and biochemical parameters monitored were haemoglobin, packed cell volume, total leukocyte count, plasma glucose, cortisol, protein albumin, globulin, blood urea nitrogen (BUN), creatinine, alanineamino transferase (ALT), sodium, potassium and chloride. The onset of analgesia (mean +/- SEM) was faster in group C (3.2 +/- 0.20 min) compared with that of group B (4.6 +/- 0.22 min) and group A (34.0 +/- 1.86 min). Analgesia of the thorax, flank, inguinal region, hind limbs, perineum and tail was complete in group C, but mild to moderate in groups A and B. Ataxia was severe in group C and mild in groups A and B. Mild to deep sedation was produced by groups A and C animals. Group B animals failed to produce sedation. Longer duration and greater depth of analgesia was produced in animals of group C. Heart rate, respiratory rate and rectal temperature decreased in groups A and C. The haematological parameters decreased in all the groups. The biochemical parameters like glucose, cortisol, BUN, creatinine, and ALT increased in all the animals. However, total proteins and albumin decreased in the three groups. The plasma electrolytes sodium, potassium and chloride did not show any significant change. The results of this study indicated a possible synergistic analgesic interaction between epidurally administered xylazine and ketamine, without causing any marked systemic effects in water buffalo calves.