Andrew J. Niehaus

Dental Disease in Llamas and Alpacas

Dental disease is common in llamas and alpacas. Many different disease conditions exist but tooth root abscesses, malocclusion, and normal aging changes are among the most common seen in the authors practice. Diagnosis is usually based on a good through history, physical examination, and radiographic examination. Although the etiology of dental infections has not been established, it is probably a combination of genetic predisposition, diet, and other management factors. Treatment is largely successful. A good prognosis depends on early diagnosis and treatment. Other conditions, such as overgrown teeth, can be easily controlled with routine management.

Pharmacokinetics of florfenicol after intravenous and intramuscular dosing in llamas.

Florfenicol, is a broad spectrum antimicrobial agent with wide tissue distribution commonly used to treat camelids. To address the lack of drug disposition data for florfenicol in llamas, we evaluated the pharmacokinetics after 20mg/kg intravenous (i.v.) and intramuscular (i.m.) dosing. Serum concentrations were determined using a HPLC-UV assay and pharmacokinetic analysis was conducted using non-compartmental analysis. Following i.v. injection, systemic clearance and Vdss in llamas were 4.6 mL/min/kg and 737 mL/kg, respectively. Mean residence time after i.v. dosing was 3h. After i.m. injection, florfenicol was rapidly absorbed, with Cmax concentrations being 3.2 μg/mL at 0.5h, mean residence time was 15 h, mean absorption time was 12h and absolute bioavailability of florfenicol after i.m. injection was 63%. The prolonged absorption of florfenicol after i.m. administration suggests the apparent HL_λz reflects the absorption process rather than elimination of the drug. Florfenicol administration was not associated with adverse reactions after dosing by either route. Serum florfenicol concentrations remained >1.0 μg/mL for 12h after i.m. administration. For susceptible pathogens, once daily dosing of 20mg/kg body weight appears appropriate.

Surgery of the Abomasum

Abomasal diseases are common in cattle. Many of these diseases can be managed surgically. This article briefly discusses the various classifications of abomasal diseases. It focuses on the surgical treatment of these diseases. Surgical principles of conventional surgery and minimally invasive techniques are discussed.

Two-way antigenic cross-reactivity between porcine epidemic diarrhea virus and porcine deltacoronavirus.

Abstract Porcine epidemic diarrhea virus (PEDV) and porcine deltacoronavirus (PdCV) cause indistinguishable clinical signs and pathological changes in swine. Here we investigated the antigenic relationship between PEDV and PdCV. We provide the first evidence that conserved epitope(s) on the respective viral nucleocapsid proteins cross-react with each other although virus neutralization cross-reactivity was not observed. As a practical matter, prevention of these two very similar diseases of swine will require the development of separate virus-specific vaccine products.

Effect of cell seeding on neotissue formation in a tissue engineered trachea.

BACKGROUND Surgical management of long segment tracheal disease is limited by a paucity of donor tissue and poor performance of synthetic materials. A potential solution is the development of a tissue-engineered tracheal graft (TETG) which promises an autologous airway conduit with growth capacity. METHODS We created a TETG by vacuum seeding bone marrow-derived mononuclear cells (BM-MNCs) on a polymeric nanofiber scaffold. First, we evaluated the role of scaffold porosity on cell seeding efficiency in vitro. We then determined the effect of cell seeding on graft performance in vivo using an ovine model. RESULTS Seeding efficiency of normal porosity (NP) grafts was significantly increased when compared to high porosity (HP) grafts (NP: 360.3 ± 69.19 × 10(3) cells/mm(2); HP: 133.7 ± 22.73 × 10(3) cells/mm(2); p<0.004). Lambs received unseeded (n=2) or seeded (n=3) NP scaffolds as tracheal interposition grafts for 6 weeks. Three animals were terminated early owing to respiratory complications (n=2 unseeded, n=1 seeded). Seeded TETG explants demonstrated wound healing, epithelial migration, and delayed stenosis when compared to their unseeded counterparts. CONCLUSION Vacuum seeding BM-MNCs on nanofiber scaffolds for immediate implantation as tracheal interposition grafts is a viable approach to generate TETGs, but further preclinical research is warranted before advocating this technology for clinical application.

Effects of orthopedic implants with a polycaprolactone polymer coating containing bone morphogenetic protein-2 on osseointegration in bones of sheep

OBJECTIVE To determine elution characteristics of bone morphogenetic protein (BMP)-2 from a polycaprolactone coating applied to orthopedic implants and determine effects of this coating on osseointegration. ANIMALS 6 sheep. PROCEDURES An in vitro study was conducted to determine BMP-2 elution from polycaprolactone-coated implants. An in vivo study was conducted to determine the effects on osseointegration when the polycaprolactone with BMP-2 coating was applied to bone screws. Osseointegration was assessed via radiography, measurement of peak removal torque and bone mineral density, and histomorphometric analysis. Physiologic response was assessed by measuring serum bone-specific alkaline phosphatase activity and uptake of bone markers. RESULTS Mean +/- SD elution on day 1 of the in vitro study was 263 +/- 152 pg/d, which then maintained a plateau at 59.8 +/- 29.1 pg/d. Mean peak removal torque for screws coated with polycalprolactone and BMP-2 (0.91 +/- 0.65 dN x m) and screws coated with polycaprolactone alone (0.97 +/- 1.30 dN.m) did not differ significantly from that for the control screws (2.34 +/- 1.62 dN x m). Mean bone mineral densities were 0.535 +/- 0.060 g/cm(2), 0.596 +/- 0.093 g/cm(2), and 0.524 +/- 0.142 g/cm(2) for the polycaprolactone-BMP-2-coated, polycaprolactone-coated, and control screws, respectively, and did not differ significantly among groups. Histologically, bone was in closer apposition to the implant with the control screws than with either of the coated screws. CONCLUSIONS AND CLINICAL RELEVANCE BMP-2 within the polycaprolactone coating did not stimulate osteogenesis. The polycaprolactone coating appeared to cause a barrier effect that prevented formation of new bone. A longer period or use of another carrier polymer may result in increased osseointegration.

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.

Stifle Disorders: Cranial Cruciate Ligament, Meniscus, Upward Fixation of the Patella

Stifle injury in cattle can be a debilitating condition. Stifle injuries often present as nonspecific lameness with subtle clinical signs. Physical examination with manipulation of the stifle joint, radiographs, and analysis of the joint fluid can help to make a diagnosis. Cranial cruciate and collateral ligament injuries are among the most common traumatic injuries of the stifle joint. Although the prognosis is guarded, better success and less degenerative change are expected with early diagnosis and treatment. Meniscal injuries and upward fixation of the patella are less commonly diagnosed, but their clinical signs, treatment, and prognosis are discussed in this article.

Cardiac Troponin I in Calves with Congenital Heart Disease

BACKGROUND The association between plasma cardiac troponin I (cTnI) and the magnitude of cardiac enlargement in calves with congenital heart disease (CHD) are not well defined. OBJECTIVE To investigate the relationship between plasma cTnI concentrations and cardiac size in healthy calves and calves with CHD. ANIMALS A total of 19 healthy calves (control) and 12 Holstein calves with CHD (patent ductus arteriosus, ventricular septal defect, tetralogy of Fallot or double outlet right ventricle). METHODS Case control study. All animals underwent a comprehensive transthoracic echocardiographic study to document cardiac health or presence of CHD. The vertebral heart score (VHS) was determined in each animal using right lateral survey radiographic images. Blood samples were collected via jugular venipuncture and plasma cTnI concentration and creatine kinase (CK) activity were determined by a 3rd generation immunoassay and an automatic biochemical analyzer, respectively. Groups were compared using Mann-Whitney U-test and receiver-operating characteristics (ROC) curve analysis. RESULTS Calves with CHD had significantly larger VHS values and higher plasma cTnI concentrations (P < .001) compared to control. Creatine kinase activity was not different between the control and CHD groups of calves. Diagnostic cutoffs of VHS and plasma cTnI for discrimination of groups were 8.9 vertebrae and 0.035 ng/mL, respectively. The cTnI concentration in plasma was significantly correlated with VHS (r (2) =0.512, P < .001). CONCLUSION AND CLINICAL RELEVANCE Our results suggest that determination of plasma cTnI concentrations in calves with clinical signs compatible with CHD might prove useful as a guide to quantify cardiac remodeling associated with increased cardiac size.

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.