Experimental use of polyamide bands in combination with intramedullary pinning for repair of oblique femoral fractures in rabbits

OBJECTIVE: To evaluate the use of polyamide bands, manufactured for securing electrical cables, for repair of oblique femoral fractures in rabbits. STUDY DESIGN: Experimental study. ANIMALS: Twelve nulliparous, 21-25-week-old, California female rabbits. METHODS: Rabbits were divided into 3 groups (n=4) and studied for 14, 28, or 56 days. A Z-shaped mid-diaphyseal femoral osteotomy was repaired with a 2.5 mm intramedullary pin and a polyamide 6.6 cerclage band. Healing was evaluated at intervals by physical examination, limb use, femoral radiographs, and callus histology. RESULTS: Rabbits had early limb use with good wound healing. From the 1st day, movement of the hip and stifle joints was satisfactory. Radiographically, fractures were healed at 28 days. Histologically, there was no foreign body reaction and bone healing was normal. CONCLUSION: Nylon cerclage band application was accomplished easily, maintained reduction, and resulted in good healing and limb use. CLINICAL RELEVANCE: Sterilized nylon bands, manufactured for electrical use, can be used for cerclage in rabbits.     

Assessing economic and social pressure for the control of bovine viral diarrhoea virus

The objective of this paper is to present a preliminary assessment of variation in the economic impact of bovine viral diarrhoea virus (BVDV) at dairy farm level between a sample of nations within the EU and hence assess differences in pressure to respond to this disease that may be impeding progress in control and hence restricting collective benefits from healthier livestock. We used a questionnaire to obtain national average values of key epidemiological and economic parameters for a typical dairy farm from BVDV experts in the countries concerned. These parameters were converted into assessments of economic impact using a computer simulation model. Uncontrolled output losses for a BVDV-na?ve herd with virus introduced in year 1 of a 10-year epidemic represented 22, 7, 8, 5, 8 and 20% of the BVDV-free annuity for the UK, Northern Portugal, Holland, Norway, Italy and Germany, respectively. Differences between countries will be widened by differences in the risk of acquiring BVDV. These will be much reduced in countries, such as Norway that have a national BVDV eradication programme. Farmers in such countries can therefore justify spending much less on maintaining BVDV-free status than BVDV-free farms in other countries. This result illustrates the paradox that in countries where BVDV prevalence is high, farmers have least to gain from unilateral BVDV eradication because of the high cost of maintaining freedom from the disease. We discuss this issue in the light of increasing recognition at international level of the importance of BVDV control.     

Comparison of bacterial organisms and their susceptibility patterns from otic exudate and ear tissue from the vertical ear canal of dogs undergoing a total ear canal ablation

The purpose of this prospective study was to compare bacterial organisms and their susceptibility patterns from otic exudate and ear tissue from the vertical ear canal of six dogs with end-stage otitis undergoing a total ear canal ablation. Twenty-six organisms, 13 from the exudate and 13 from the tissue, were morphologically and biochemically similar, and their susceptibility patterns were compared. There were discrepancies for only 5 antibiotics for 4 organisms from 3 dogs. Culture of otic exudate from the vertical ear canal of dogs with chronic end-stage otitis externa provides an accurate reflection of the bacterial species present and the antimicrobial susceptibility patterns of these infections.     

Inhibitory effects of the beta-adrenergic receptor agonist zilpaterol on the LPS-induced production of TNF-alpha in vitro and in vivo

In this study the anti-inflammatory properties of zilpaterol, a beta2-adrenergic receptor (AR) agonist specifically developed as a growth promoter in cattle were investigated. Although zilpaterol has a different structure compared with the beta2-AR agonists known to date, it was noted that it was able to bind to both the beta2-AR (Ki = 1.1 x 10(-6)) and the beta1-AR (Ki = 1.0 x 10(-5)). Using lipopolysaccharide (LPS)-exposed U937 macrophages, the production of cyclic adenosine-3',5'-cyclic monophosphate (cAMP) and tumor necrosis factor alpha (TNF-alpha) were investigated. Zilpaterol inhibited TNF-alpha release and induced intracellular cAMP levels in a dose-dependent manner. The inhibition of TNF-alpha release and induction of cAMP production was mainly mediated via the beta2-AR, as indicated by addition of beta1- and beta2-specific antagonists. The effects of zilpaterol were investigated in LPS-treated male Wistar rats after pretreatment with zilpaterol. Zilpaterol dosed at 500 microg/kg body weight reduced the TNF-alpha plasma levels. In conclusion, zilpaterol is a beta2-adrenergic agonist and an inhibitor of TNF-alpha production induced by LPS both in vivo and in vitro.     

The O-antigen of Salmonella enterica serotype Enteritidis PT4: a significant factor in gastrointestinal colonisation of young but not newly hatched chicks

The lipopolysaccharide of Salmonella and other Gram negative pathogenic species has been implicated as a major virulence determinant and in this study we report the role of LPS of S. Enteritidis in the colonisation and persistent gastrointestinal infection of young poultry. The gene encoding the unique O-antigen ligase, waaL, was mutated by insertional inactivation in a well characterised S. Enteritidis strain, S1400/94. The waaL mutant, designated PCP, produced rough colonies on agar medium, did not agglutinate O9 antiserum, did not produce an LPS ladder on silver stained gels and was serum sensitive. PCP and a nalidixic acid marked derivative of S1400/94 (S1400/94 Nalr) were used to orally challenge young chicks, separately and together in competitive index experiments. At post-mortem examination of 1-day-old chicks challenged S1400/94 Nalr and PCP separately there were no significant differences in the numbers of S1400/94 Nalr and PCP bacteria in tissues sampled on days 1, 2, and 5. By day 42 after challenge S1400/94 Nalr bacteria were recovered in significantly higher numbers than PCP from the caecal contents (P < 0.001). In competitive index studies in the 1-day-old chick PCP colonised, invaded and persisted in lower numbers than S1400/94 Nalr. In 4-week-old chicks challenged separately, PCP bacteria were recovered from all tissues examined in significantly lower numbers than S1400/94 Nalr. In competitive index experiments in 4-week-old chicks, PCP was not detected at any site and at any time point. Therefore, the O-antigen of S. Enteritidis plays an important role in poultry infections although this role is less important in the newly hatched chick.     

Validation of the FAMACHA eye color chart for detecting clinical anemia in sheep and goats on farms in the southern United States

Recent studies on sheep and goat farms in the southern United States indicate that multiple-anthelmintic resistance in Haemonchus contortus is becoming a severe problem. Though many factors are involved in the evolution of resistance, the proportion of the parasite population under drug selection is believed to be the single most important factor influencing how rapidly resistance develops. Therefore, where prevention of resistance is an important parallel goal of worm control, it is recommended to leave a portion of the animals untreated. Recently, a novel system called FAMACHA was developed in South Africa, which enables clinical identification of anemic sheep and goats. When H. contortus is the primary parasitic pathogen, this system can be applied on the farm level to reduce the number of treatments administered, thereby increasing the proportion of the worm population in refugia. Since most studies validating the FAMACHA method have been performed in South Africa, it is important that the method be tested in other regions before its use is broadly recommended. We performed a validation study of FAMACHA by testing the system in sheep (n = 847) and goats (n = 537) of various breeds and ages from 39 farms located in Arkansas, Georgia, Louisiana, Florida, and the US Virgin Islands. The color of the ocular conjunctiva of all animals were scored on a 1-5 scale using the FAMACHA card, and blood samples were collected from each animal for determination of packed cell volume (PCV). Fecal samples were also collected from a majority of the animals tested for performance of fecal egg counts (FEC). Correlations between PCV and eye scores, PCV and FEC, and FEC and eye scores were all highly significant for both sheep and goats (P < 0.001). Data for both FAMACHA scores and PCV were evaluated using two separate criteria for anemia: eye score values of 3, 4 and 5 or 4 and 5, and PCV values of < or =19 or < or =15 were considered anemic. Specificity was maximized when eye score values of 4 and 5 were considered anemic and PCV cut off for anemia was < or =19, but sensitivity was low. In contrast, sensitivity was 100% for both sheep and goats when eye score values of 3, 4 and 5 were considered anemic and PCV cut off was < or =15, but specificity was low. In both sheep and goats, predictive value of a negative was greater than 92% for all anemia and eye score categories, and was greater than 99% for both eye score categories when an anemia cutoff of < or =15 was used. Predictive value of a positive test was low under all criteria indicating that many non-anemic animals would be treated using this system. However, compared to conventional dosing practices where all animals are treated, a large proportion of animals would still be left untreated. These data indicate that the FAMACHA method is an extremely useful tool for identifying anemic sheep and goats in the southern US and US Virgin Islands. However, further studies are required to determine optimal strategies for incorporating FAMACHA-based selective treatment protocols into integrated nematode control programs.     

Pancreatic exocrine secretion and plasma concentration of some gastrointestinal hormones in response to abomasal infusion of starch hydrolyzate and/or casein

Eight Angus steers (290 +/- 8 kg), surgically prepared with pancreatic pouch-duodenal reentrant cannulas and abomasal infusion catheters were used in a replicated 4 x 4 Latin square experiment to investigate the effects of abomasal infusion of starch hydrolyzate (SH) and/or casein on pancreatic exocrine secretion and plasma concentration of hormones. Steers were fed a basal diet of alfalfa (1.2 x NEm) in 12 equal portions daily. Abomasal infusion treatments (6-L total volume infused per day) were water (control), SH [2.7 g/(kg BW x d)], casein [0.6 g/(kg BW x d)], and SH + casein. Periods were 3 d for adaptation and 8 d of full infusion. Pancreatic juice and jugular blood samples were collected over 30-min intervals for 6 h on d 11. Weight and pH of pancreatic samples were measured, and a 10% subsample was composited and frozen until analysis of total protein and pancreatic enzyme activities. The remaining sample was returned to the duodenum. Plasma was harvested and frozen until analyzed. Pancreatic juice (67 mL/h) and protein (1.8 g/h) secretion rates were not affected by nutrient infusion. There were SH x casein interactions for all pancreatic enzyme secretions (U/h; alpha-amylase, P < 0.03; trypsin, P < 0.08; and chymotrypsin, P < 0.03) and plasma insulin concentration (P < 0.10). Secretion of pancreatic enzymes was increased by SH (trypsin) and casein (alpha-amylase, trypsin, and chymotrypsin) but not when SH + casein were infused together. Glucose (P < 0.10) and cholecystokinin octapeptide concentrations (CCK-8; P < 0.05) were increased by SH, but glucagon was decreased (P < 0.10). Casein decreased (P < 0.10) plasma CCK-8 concentrations. These data indicate that positive effects of postruminal casein on enzyme secretion were inhibited by SH, emphasizing the complexity of the regulatory mechanisms involved in dietary adaptation of pancreatic exocrine secretion. Changes in hormone concentration may not relate directly to changes in enzyme secretion.     

Comparison of bupivacaine femoral and sciatic nerve block versus bupivacaine and morphine epidural for stifle surgery in dogs

ObjectiveTo evaluate the efficacy of combined femoral and sciatic nerve blocks as an alternative to epidural anesthesia and analgesia in dogs undergoing stifle surgery under general anesthesia.Study designProspective, blinded, randomized, clinical comparison.AnimalsTwenty dogs weighing 37 ± 11 (mean ± SD) kg, aged 3 (1–8) [median (minimum–maximum)] years undergoing elective unilateral tibial-plateau leveling osteotomy.MethodsDogs were assigned randomly to receive either epidural anesthesia (bupivacaine 0.5%, 0.5 mg kg^?1 + morphine 0.1%, 0.1 mg kg^?1, in 0.2 mL kg^?1; EPID) or femoral and sciatic nerve blocks (Bupivacaine 0.5%, 0.1 mL kg^?1, was administered at each site; F + S) guided by electrolocation. All patients received a standard general anesthesia technique. Pain and sedation were scored (on scales of 0–10 and 0–3, respectively) pre-operatively, at extubation, and at 1, 4 and then every 4 hours thereafter up to 24 hours. Postoperatively, hydromorphone was administered to any patient with a pain score of >5 or whenever the blinded caregiver determined that more hydromorphone was necessary. Intraoperative heart rate (HR), mean arterial pressure (MAP), end tidal isoflurane (FE′ISO), body temperature, post-operative pain scores, time to first hydromorphone dose after surgery, time to first feeding, time to first drinking, time to first urination, time to first ambulation (walk on a lead) and cumulative dose of hydromorphone were recorded.ResultsIntra-operatively, FE′ISO and MAP were significantly lower in the EPID group (p = 0.05 and p = 0.04, respectively). Postoperatively, the cumulative hydromorphone consumption (p = 0.04) and the incidence of urinary retention (p = 0.03) were higher in the EPID group.Conclusion and clinical relevance F + S is a practical alternative to EPID that produces less urine retention and reduces opioid consumption in the 24 hours after surgery. EPID might be associated with a lower isoflurane requirement and lower systemic blood pressure.