Objective-To determine the effects of ketamine hydrochloride, xylazine hydrochloride, and lidocaine hydrochloride after subarachnoid administration in goats. Animals-6 healthy goats. Procedure-In each goat, ketamine (3 mg/kg), xylazine (0.1 mg/kg), lidocaine (2.5 mg/kg), and saline (0.9% NaCl) solution were injected into the subarachnoid space between the last lumbar vertebra and first sacral vertebra (time 0). Analgesic, ataxic, sedative, cardiovascular, and respiratory effects and rectal temperature were evaluated before (baseline) and 2, 5, 10, 15, and 30 minutes after administration and at 30-minute intervals thereafter as needed. Results-Administration of anesthetics induced varying degrees of analgesia. Onset of the analgesic effect was more delayed for xylazine (mean +/- SD, 9.5 +/- 2.6 minutes) than for ketamine (6.7 +/- 2.6 minutes) or lidocaine (3.5 +/- 1.2 minutes). Duration of analgesia induced by xylazine (88.3 ± 15 minutes) was twice as long as the duration of analgesia induced by ketamine (48.8 ± 13.5 minutes) but similar to that induced by lidocaine (66.5 ± 31 minutes). Xylazine induced bradycardia, whereas ketamine caused a nonsignificant increase in heart rate. Xylazine induced a reduction in arterial pressure, whereas ketamine or lidocaine did not affect arterial pressure. Conclusion and Clinical Relevance-Subarachnoid administration of xylazine in goats resulted in longer duration of analgesia of the tail, perineum, hind limbs, flanks, and caudodorsal rib areas than administration of ketamine or lidocaine. However, xylazine caused bradycardia and respiratory depression. Additional studies are needed to determine whether the analgesia would be sufficient to allow clinicians to perform surgical procedures.

The objective of this prospective clinical study was to evaluate the accuracy of pulse oximetry and capnography in healthy and compromised horses during general anesthesia with spontaneous and controlled ventilation. Horses anesthetized in a dorsal recumbency position for arthroscopy (n = 20) or colic surgery (n = 16) were instrumented with an earlobe probe from the pulse oximeter positioned on the tip of the tongue and a sample line inserted at the Y-piece for capnography. The horses were allowed to breathe spontaneously (SV) for the first 20 min after induction, and thereafter ventilation was controlled (IPPV). Arterial blood, for blood gas analysis, was drawn 20 min after induction and 20 min after IPPV was started. Relationships between oxygen saturation as determined by pulse oximetry (SpO2), arterial oxygen saturation (SaO2), arterial carbon dioxide partial pressure (PaCO2), and end tidal carbon dioxide (P(et)CO2), several physiological variables, and the accuracy of pulse oximetry and capnography, were evaluated by Bland–Altman or regression analysis. In the present study, both SpO2 and P(et)CO2 provided a relatively poor indication of SaO2 and PaCO2, respectively, in both healthy and compromised horses, especially during SV. A difference in heart rate obtained by pulse oximetry, ECG, or palpation is significantly correlated with any pulse oximeter inaccuracy. If blood gas analysis is not available, ventilation to P(et)CO2 of 35 to 45 mmHg should maintain the PaCO2 within a normal range. However, especially in compromised horses, it should never substitute blood gas analysis.

The heads of nine 2.5 to 3-year-old Nile crocodiles (Crocodylus niloticus) were obtained from a commercial farm where crocodiles are raised for their skins and meat. The animals from which these specimens originated were clinically healthy at the time they were slaughtered. A detailed description of the macroscopic and microscopic features of the palate and gingivae of the Nile crocodile is presented and the results are compared with published information on this species and other Crocodylia. The histological features are supplemented by information supplied by scanning electron microscopy. Macroscopic features of interest are the small conical process situated at the base of the first two incisors of the maxilla, the distribution of cobbled units on the palate, and the broad dentary shelf forming the rostral aspect of the mandible. Histologically the palate and gingivae did not differ significantly from each other and both regions showed a presence of Pacinian-type corpuscles. Two types of sensory structures (taste receptors and pressure receptors) were identified in the regions examined, both involving modification of the epithelium and the underlying connective tissue.

The presence of bovine viral diarrhoea virus in South Africa has been confirmed by several serological surveys. However, little is known about its biological properties. Twenty five isolates obtained by isolation in tissue culture and detected by means of the antigen capture ELISA from clinically sick cattle and from foetal calf serum in South Africa were characterized on the basis of analysis of the 5' non-translated (NTR) region of the genome. A reverse-transcription polymerase chain reaction (RT-PCR) was used to amplify specific sequences from the 5'NTR of the genome. The oligonucleotide primers corresponding to positions 105-125 and 399-378, respectively, in the sequence of BVDV strain NADL were used to generate the PCR products. Both strands were sequenced directly with these primers and fluorescence-labelled dideoxynucleotides in an automated nucleic acid sequencer. Reference strains of pestiviruses [(BVDV type I, BVDV type II, border disease virus (BDV) and hog cholera virus (HCV)] and isolates from a previous investigation on BVDV in southern Africa were included for comparative purposes. All the BVDV strains obtained during this study belong to subgroups of BVDV genotype I. No association could be demonstrated between the geographic origin of the isolates. A number of isolates formed another branch separate from the existing branches Ia, Ib and Ic. These findings suggest that extensive genetic diversity can be found within BVDV type I isolates from southern Africa. Isolates that group with the classical BVDV type I strains, particularly of American origin, coexist with variants that appear to represent a local genetic pool and or variants evolving from the classical strains.

Memory is a property common to a diverse range of tissues. Cardiac memory has been demonstrated in the human, dog, rat and rabbit. This is a peculiar phenomenon, reflected in the T wave of the electrocardiogram. The heart is able to remember periods of alterations in the sequence of ventricular activation and once there is a return to a normal sequence of ventricular activation the T waves may manifest memory. Cardiac memory is noted when the T wave during normal ventricular activation retains the vector of the previous abnormal QRS complex, caused by a period of altered ventricular activation. Possible mechanisms of memory in the heart are alterations of the transient outward potassium current (Ito) in ventricular myocytes and new protein synthesis inside myocytes. These two mechanisms operate in short- and long-term cardiac memory respectively. Currently, it is unknown whether memory may have adverse structural consequences in the heart. We were able to demonstrate memory in the hearts of Dorper wethers and this is the first report of cardiac memory in Dorper sheep.

The medical, veterinary and economic importance of blackflies in South Africa, and the historical development of blackfly control programmes in various South African rivers, are reviewed in this paper. In 1996 it was estimated that blackflies can cause more than R 88 million damages per annum along the middle and lower Orange River where Simulium chutteri is considered the main pest species. A clear link between the construction of dams and the spread of the blackfly problem was shown. Four phases characterize the development of blackfly control in South Africa: (1) during the 1960s blackflies in the Vaal River were controlled with DDT; (2), during the 1970s and into the 1980s blackflies were controlled using water-flow manipulation; (3) when used at strategic times, water-flow manipulation could be used to enhance the effect of natural predator populations; and (4) during the 1990s the organophosphate temephos and toxins produced by the bacterium Bacillus thuringiensis var. israelensis were tested for their efficacy against blackflies. The larvicides temephos and B. thuringiensis proved to be effective and are still used in several control programmes. The latest research focuses on the factors that influence adult blackfly survival and annoyance, as well as the development of methods that can be used to protect sheep from blackfly attacks.

During winter populations of Argas arboreus from heronries of the cattle egret, Bubulcus ibis, in South Africa are composed of adults, with some predominance of males, and II-IV instar nymphs, in a state of diapause. The period of tick activity, including reproduction and development of eggs, larvae and N1 nymphs, is synchronized with the nesting and breeding season of their avian hosts. It begins during spring with the return of birds to the heronry, and ceases in autumn through induction of reproductive diapause in engorged females, and behavioural diapause in unfed nymphs and adult ticks. Many ticks showed morphological anomalies and malformations, the study of which could possibly be used for monitoring of environmental pollution.

Objective-To determine magnitude and duration of the effect of oral administration of methazolamide at 2 dosages on intraocular pressure (IOP) in dogs in single- dose and multiple-dose trials and to determine aqueous humor flow rate (AHFR) by use of anterior segment fluorophotometry before and during treatment. Animals-25 healthy adult Beagles. Procedure-Baseline IOPs and AHFRs were determined on days 0 and 1, respectively. On day 2, the single-dose trial was initiated with oral administration of 25 or 50 mg of methazolamide at 7 AM to 2 groups of 10 dogs each. Five dogs served as controls. In the multiple-dose trial, the same dogs received 25 or 50 mg of methazolamide at 7 AM and at 3 and 11 PM on days 3 through 9. Results-Intraocular pressures varied diurnally with highest IOPs in the morning. In the single-dose trial, IOP decreased significantly at 3 to 6 hours after treatment and then increased significantly at later time points, compared with baseline values. In the multipledose trial, dogs in both treatment groups had significantly lower IOPs during the treatment period at 10 AM and 1 PM but not at 6 and 9 PM, compared with baseline values. In both treatment groups morning IOPs had returned to baseline values by the first day after treatment. Evening IOPs were significantly increased by 2 to 3 days after treatment, compared with baseline values. The AHFRs in both treatment groups were significantly lower than pretreatment AHFRs. Conclusions and Clinical Relevance-Oral administration of methazolamide decreases IOPs and AHFRs in clinically normal dogs, with effectiveness diminishing in the evening.

Objective-To use threshold concentrations of acetone and beta-hydroxybutyrate in milk and serum, respectively; identify risk for ketosis and endometritis; and assess analyses of blood and milk samples as predictors of risk for ketosis in high-yielding dairy cows. Animals-90 multiparous Holstein cows. Procedure-At intervals before and after parturition, blood samples were obtained for determination of glucose, nonesterified fatty acids, leptin, insulin, insulin-like growth factor-1, and beta-hydroxybutyrate concentrations. Samples of milk were obtained at similar intervals after parturition for determination of fat content and concentrations of acetone, protein, and lactose. Reproductive examination of each cow was performed weekly. Results-For each cow, threshold concentrations of acetone and β-hydroxybutyrate were calculated as 75th and 90th percentiles of maximum postpartum concentrations of acetone in milk (0.40 and 0.87 mmol/L) and β-hydroxybutyrate in serum (2.30 and 3.51 mmol/L). Significant decrease in milk production (442 to 654 kg of energy-corrected milk/305-day period per cow) was associated with acetone or beta-hydroxybutyrate in excess of threshold values. Milk acetone concentrations > 0.40 mmol/L were associated with 3.2 times higher risk for endometritis. Low plasma glucose, high serum beta-hydroxybutyrate, and high milk acetone concentrations during week 1 after parturition were indicators of increased risk for ketosis later during lactation. Conclusions and Clinical Relevance-Determination of milk acetone concentration during the week after parturition may identify cows at risk for ketosis and endometritis; with appropriate interventions, development of disease and production losses may be reduced.

Objective-To determine whether the nonsteroidal anti-inflammatory drugs (NSAIDs) carprofen, flunixin meglumine, and phenylbutazone have cyclooxygenase (COX)-independent effects that specifically inhibit activation of the proinflammatory transcription factor nuclear factor kappa B (NfκB). Study Population-Purified ovine COX-1 and -2 and cultures of RAW 264.7 murine macrophages. Procedure-The COX-1 and -2 inhibitory effects of the NSAIDs were tested in assays that used purified ovine COX-1 and -2. Prostaglandin production was analyzed by use of a radioimmunoassay. Inhibitory effects of these drugs on lipopolysaccharide (LPS)- induction of inducible nitric oxide synthase (iNOS) and LPS-stimulated translocation of NfκB were determined by use of RAW 264.7 murine macrophages. Results-Flunixin meglumine and phenylbutazone were selective inhibitors of COX-1. Carprofen and flunixin meglumine, but not phenylbutazone, inhibited LPS-induction of iNOS. Carprofen and, to a lesser degree, flunixin meglumine had inhibitory effects on NFκB activation. Conclusions and Clinical Relevance-The ability of drugs such as carprofen and flunixin meglumine to inhibit activation of NfκB-dependent genes such as iNOS, in addition to their effects on COX, suggests an additional mechanism for their anti-inflammatory effects and may explain the ability of flunixin meglumine to be an effective inhibitor of the effects of endotoxin in horses with endotoxemia.