Depressed potential for interleukin-2 production following early weaning of piglets.

Spleen cells, but not mesenteric lymph node cells, from 3-week-old piglets abruptly weaned onto a soya-based diet, produced less interleukin-2 (IL-2) following non-specific activation with concanavalin A (Con A) than did cells from age- and litter-matched, unweaned controls. In contrast, the ability to express receptors for IL-2 was only marginally reduced. The effect on IL-2 production was most marked in animals weaned for as little as 24-48 h. Variation within groups increased with time after weaning, indicating differences between individuals in the longer-term effects of weaning. This finding may be due to endogenous production of steroids resulting in generalised impaired immune function or to retention of cells within intestinal sites owing to an active local immune response.     

Binding of Salmonella strains to immobilized intestinal mucosal preparations from broiler chickens.

The binding kinetics of radiolabeled Salmonella california 1989/O (mannose-sensitive hemagglutinin-positive [MSHA+]) to immobilized mucus or enterocytes isolated from broiler ceca and inhibition of binding by D-mannose and sodium metaperiodate were characteristic of adherence of mannose-sensitive type 1 fimbriae of bacteria to eukaryotic mannose-containing receptors. Binding by radiolabeled strains 1989/O (in the presence of D-mannose) and S. typhimurium S 7471 N (MSHA-, non-fimbriated) indicated non-specific binding that was characterized by less binding to enterocytes and mucus and lack of inhibition by carbohydrates or prior treatment with sodium metaperiodate. Inhibition of non-specific binding to enterocytes by pretreatment with various enzymes or by the presence of tetramethylurea or p-nitrophenol (known to disrupt hydrophobic interactions) indicate involvement of multiple sites and hydrophobic bonding. Strain-specific outer-membrane preparations inhibited non-specific binding to a greater extent than did lipopolysaccharide, Escherichia coli outer-membrane preparations, or bovine serum albumin.     

A comparison of systolic blood pressure measurement obtained using a pulse oximeter, and direct systolic pressure measurement in anesthetized sows.

Systolic blood pressure measurement obtained with a pulse oximeter has been compared to values obtained by other indirect methods in man. Direct pressure measurement is subject to less error than indirect techniques. This study was designed to compare systolic pressure values obtained using a pulse oximeter, with values obtained by direct arterial pressure measurement. The pulse oximeter waveform was used as an indication of perfusion. A blood pressure cuff was applied proximal to the pulse oximeter probe. The cuff was inflated until the oximeter waveform disappeared, this value was recorded as the systolic pressure at the disappearance of the waveform (SPD). The cuff was inflated to a pressure > 200 mmHg, then gradually deflated until the waveform reappeared, this value was recorded as the systolic pressure at reappearance of the waveform (SPR). The average of the two values, SPD and SPR, was calculated and recorded as SPA. The study was performed in sows (n = 21) undergoing cesarean section under epidural anesthesia and IV sedation. A total of 280 measurements were made of SPD, SPR and SPA. Regression analysis of SPA and direct measurement revealed a correlation coefficient (r) of 0.81. Calculation of mean difference (bias) and standard deviation of the bias (precision) for direct pressure--SPA revealed a value of 1.3 +/- 12.1. When compared with direct measurement, the correlation of this technique was similar to that recorded for other indirect techniques used in small animals. This indicates that this technique would be useful for following systolic pressure trends.(ABSTRACT TRUNCATED AT 250 WORDS)     

Routine castration in 568 draught colts: incidence of evisceration and omental herniation

REASONS FOR PERFORMING STUDY: Castration is one of the most common routine surgical procedures performed in the horse, from which a number of potential complications can arise. We undertook a prospective evaluation of short-term complications associated with castration of draught colts over a 3-year period (1998-2000). OBJECTIVES: To compare castration complications in a large number of draught foals with previously published literature. METHODS: Five hundred and sixty-eight draught colts, age 4 or 5 months, were castrated in field conditions. Foals were observed for complications for 24 h post operatively. RESULTS: There was no significant difference in complication rates between open and closed surgical techniques. Inguinal/scrotal hernia rate was 4.6% (26/568) prior to surgery, and evisceration of the small intestine occurred in 4.8% (27/568). Foals observed to eviscerate underwent immediate surgical correction with an overall survival rate of 72.2% (13/18). Omental herniation was seen in 2.8% (16/568) of colts. CONCLUSIONS: This study showed no difference between the closed and open techniques of castration and the rate of omental herniation or evisceration. The evisceration rate in combination with the omental and presurgical herniation rates approached 12.2%, which is high enough to warrant further examination. POTENTIAL RELEVANCE: Future investigation should help to assess predisposing factors for evisceration. Regardless of the technique employed, herniation appears to pose a significant risk to draught foals undergoing castration.     

Detection of airborne Salmonella enteritidis in the environment of experimentally infected laying hens by an electrostatic sampling device

Bacteriologic culturing of environmental samples taken from sources such as manure pits and egg belts has been the principal screening tool in programs for identifying commercial laying flocks that have been exposed to Salmonella enteritidis and are thus at risk to produce contaminated eggs. Because airborne dust and aerosols can carry bacteria, air sampling offers a potentially efficient and inexpensive alternative for detecting S. enteritidis in poultry house environments. In the present study, an electrostatic air sampling device was applied to detect S. enteritidis in a room containing experimentally infected, caged laying hens. After oral inoculation of hens with a phage type 13a S. enteritidis strain, air samples were collected onto agar plates with the electrostatic sampling device, an impaction air sampler, and by passive exposure to the settling of aerosols and dust. Even though the floor of the room was cleaned once per week (removing most manure, dust, and feathers), air samples were positive for S. enteritidis for up to 4 wk postinoculation. On the basis of both the number of S. enteritidis colonies observed on incubated agar plates and the frequency of positive results, the efficiency of the electrostatic device was significantly greater than that of the passive exposure plates (especially at short collection intervals) and was similar to that of the far more expensive impaction sampler. The electrostatic device, used for a 3-hr sampling interval, detected airborne S. enteritidis on 75% of agar plates over the 4 wk of the study.     

A romifidine and morphine combination for epidural analgesia of the flank in cattle

The objective of the study reported here was to determine the onset, duration, and degree of analgesia achieved with a combination of romifidine (50 microg/kg body weight [BW]) and morphine (0.1 mg/kg BW) administered epidurally. Ten adult Holstein Friesen cows were assigned to either a treatment group receiving the romifidine and morphine combination or a control group receiving 0.9% saline in a randomized, blinded, crossover design. Cows were assessed for degree of flank analgesia and systemic sedation at various time intervals over a period of 24 hours. The romifidine and morphine combination, compared with saline, provided significant analgesia for at least 10 minutes (P = 0.016) and up to 12 hours (P = 0.004) after epidural administration. Treated cows were sedate between 10 minutes (P = 0.016) and 6 hours (P = 0.002) after epidural administration. These results provide evidence for a potential cost-effective intra- and postoperative method of analgesia; however, the sedation seen in this study could be detrimental to patients expected return to the farm shortly after surgery. Further research into withdrawal times, systemic effects, and potential adverse effects are needed before an opiod and alpha2-adrenergic agonist combination can be used safely in a clinical setting.     

Current research and theories on the pathogenesis of acute laminitis in the horse

A large number of studies have been undertaken in recent years aimed at furthering our understanding of the complex mechanisms underlying the common and debilitating condition of acute laminitis in the horse. Many of these studies have either reinforced or cast doubt on previously held theories on the pathogenesis of this disease, while others have suggested new mechanisms which may play a key role in its development. This review seeks to put the current hypotheses into the context of this recent body of evidence. While a unifying theory may not yet seem to be achievable, this review demonstrates that most of the current theories are not mutually exclusive. Studies utilising in vitro and in vivo models of the disease, particularly addressing the areas of inflammation, haemodynamic disturbances and enzyme activation in the hoof, as well as the preceding events occurring in the hindgut, have helped to explain many clinical observations of the disease and may possibly lead to more effective therapies and means of prevention in the future.