The uptake and distribution of radioselenium in the larvae of Fasciola hepatica and its snail host Lymnaea columella

Radiolabeled metacercariae of Fasciola hepatica were obtained in vivo by incubating infected Lymnaea columella snails with 20 muCi radioselenomethione (75Se-M) per snail in 5 ml of water for 5 h, or in vitro by incubating a batch of unlabeled F. hepatica metacercariae with 75Se-M for 24 h. Radioassay showed that only 5% of the 75Se-M was incorporated into maritas (juvenile flukes) from the in vivo labeled metacercariae. The inner cyst wall of in vivo labeled metacercariae contained 46% of the total activity, of which 21% was dissolved in the excysting medium. The outer, tan-colored cyst wall contained 49% of the radioactivity. Through diffusion/attachment, maritas from in vitro labeled metacercariae could occasionally be labeled with 0.4% of the total radioactivity. However, the activity was lost after inoculation into the body of mice. The outer and inner cyst walls of in vitro labeled metacercariae contained 92% and 7.6%, respectively, of the total activity. Microautoradiography demonstrated that 75Se-M was evenly distributed in the body of marita and the cyst wall of inner and outer layers from an in vivo labeled metacercaria. A 9 X 4 micron rectangularly-shaped aggregate of Ag degree grains was present on the outer periphery of the inner cyst wall. Microautoradiography of in vitro labeled metacercariae demonstrated a significant concentration of Ag degree grains on the cyst walls. The ventral plug contained fewer Ag degree grains per unit area compared to the other portion of the inner cyst wall. Uptake and distribution of 75Se-M in the snail host were also studied. It appeared that rediae and cercariae tended to concentrate the label in the foot, the mantle and the digestive gland. Little or no radioactivity was present in the areas where F. hepatica larvae were not found.     

Evaluation of the diagnostic and prognostic utility of ultrasonography at first diagnosis of presumptive bovine respiratory disease

This project investigated the use of ultrasonography at first diagnosis of presumptive early bovine respiratory disease (BRD) in feedlot cattle from western Canada. One hundred seventy-four cattle (116 cases and 58 controls) at high risk of developing BRD were enrolled in a prospective longitudinal study over 2 y (2006-2007). Cattle with clinical signs relating to the respiratory system and assessed as sick at the time of feedlot arrival (arrival fever cases) or assessed as sick in the pen 3 to 30 d post-arrival (post-arrival fever cases, post-arrival no fevers cases) were eligible for enrollment. Control animals were identified at the time of case enrollments. Ultrasonography was done using a 3.5 sector transducer at enrollment and at 2, 4, and 6 wk post-enrollment. Lung lesions were identified at least 1 time over the course of the trial in 32/116 (28%) cases and 9/58 (16%) controls. At enrollment, lung lesions were identified in 20/115 (17%) cases and 2/55 (4%) controls (data unreadable n = 4). Post-arrival fever cases (14/48) were the most likely to have a lesion identified using ultrasound. In arrival fever cases, average daily gain (enrollment to last ultrasound, average 34 d) was improved (P = 0.007) in cattle identified with a lesion at enrollment using ultrasound compared with those not identified with a lesion at that time, potentially demonstrating the effects of gut fill at arrival weighing, as these sicker animals may have eaten less prior to arrival and, therefore, had more room for improvement in weight over time due to restoration of normal gut fill. None of the ultrasound time points explored (enrollment, 2, 4, or 6 wk post-enrollment) were associated with the animal health outcomes of interest (subsequent treatment, chronicity, wastage, or mortality) for cattle enrolled at arrival or post-arrival.Ultrasonography using a 3.5 sector transducer was not particularly effective as a prognostic/diagnostic tool for early detection of BRD, but may be useful in targeted populations of animals with respiratory disease of longer duration (such as chronic pens).     

Equilibration and passage of water in the gastrointestinal tract of cattle in relation to estimating body water by compartmental kinetic models

The volume of water in the rumen of four steers was increased (P less than .01) 47% when the level of ground cobs in the diet fed to the steers was changed from 10% to 50%. The difference in gut water content due to diet was not accurately (P greater than .10) estimated by deuterium oxide dilution using either one-, two- or three-compartmental models. Gut water was overestimated and empty body water underestimated when calculated by two-compartment models. The proportions of total body water within each compartment of a three-compartment model were quite variable among steers. When the two-compartment model was solved on the basis of measurements taken from either compartment, different compartment volumes were obtained. This indicated that the two-compartment model did not accurately describe the water equilibration process. Water in the contents of the proximal duodenum and terminal ileum equilibrated with blood in 30 min (range, 10 to 75 min), fecal water equilibrated in 4.3 h (range, 1.7 to 6.7 h) and water in rumen contents equilibrated in 8.3 h (range, 3.8 to 12.5 h). Diet did not affect (P greater than .10) equilibration time or the mean retention time of water in the gastrointestinal tract. Mean retention time was much longer than equilibration time; thus, the equilibration of water in the gastrointestinal tract contents was primarily dependent upon movement of water across the gut mucosa and not upon the flow of water through the gut. One-third of the water in the contents of the gastrointestinal tract was located outside the rumen. Compartmental modeling based only upon D2O disappearance from blood did not enable either gut water or rumen water to be accurately estimated.     

Effect of intranasal exposure to leukotoxin-deficient Mannheimia haemolytica at the time of arrival at the feedyard on subsequent isolation of M haemolytica from nasal secretions of calves

OBJECTIVE: To determine the effect of intranasal exposure to live leukotoxin (LktA)-deficient Mannheimia haemolytica (MH) at the time of feedyard arrival on nasopharyngeal colonization by wild-type MH in calves. ANIMALS: 200 calves. PROCEDURE: Calves from Arkansas (AR calves; n = 100; mean body weight, 205 kg) were purchased from an order buyer barn. Calves from New Mexico (NM calves; n = 100; mean body weight, 188 kg) were obtained from a single ranch. Calves were transported to a feedyard, where half of each group was exposed intranasally with LktA-deficient MH at the time of arrival. Calves were observed daily for respiratory tract disease (RTD), and nasal swab specimens were collected periodically to determine nasopharyngeal colonization status with MH. Serum samples were assayed for antibodies to MH. RESULTS: 15 AR calves had nasopharyngeal colonization by wild-type MH at the order buyer barn, whereas none of the NM calves had nasopharyngeal colonization. Intranasal exposure to LktA-deficient MH elicited an increase in serum antibody titers against MH in NM calves, but titers were less in NM calves treated for RTD. Exposure of NM calves to LktA-deficient MH offered protection from nasopharyngeal colonization by wild-type MH. CONCLUSIONS AND CLINICAL RELEVANCE: Exposure of calves to LktA-deficient MH elicited an increase in serum antibody titers against MH and decreased colonization of the nasopharynx by wild-type MH. Earlier exposure would likely allow an immune response to develop before transportation and offer protection from nasopharyngeal colonization and pneumonia caused by wild-type MH.     

Road transportation affects blood hormone levels and lymphocyte glucocorticoid and beta-adrenergic receptor concentrations in calves

The effect of transportation on blood cortisol and catecholamine levels, lymphocyte glucocorticoid receptor (GR) and beta-adrenergic receptor (beta-AR) concentrations was investigated in calves. Blood samples were collected from 24 six-month-old calves before departure (T(0)), on arrival (T(1)), and at 24 h (T(2)) and one week (T(3)) after arrival. Animals were loaded and transported about 950 km, from the Midy-Pyrenes region (Cahors, France) to the Piedmont region (Italy), over a total of 14 h. Serum cortisol levels and plasma catecholamines (adrenaline, noradrenaline) were determined by radioimmunoassay. Lymphocyte GRs and beta-ARs were measured through binding assays. A significant (P < 0.05) increase in cortisol and catecholamine concentrations was observed immediately after transport. The increase in hormone levels at time T(1) was negatively correlated with lymphocyte GR and beta-AR concentrations. At times T(2) and T(3), blood cortisol and catecholamine levels and lymphocyte GRs and beta-ARs returned to normal. The results demonstrate the activation of the hypothalamic-pituitary-adrenal axis and the catecholaminergic system in long-term transported calves. However, these systems returned to normal within 24 h after the end of transport.     

Effects of road transportation on lymphocyte subsets in calves

The effect of transportation on peripheral blood lymphocyte subsets in 24 calves was investigated by flow cytometry. Blood was collected before departure, on arrival, at 24h and 1 week after arrival. Highest leucocyte and neutrophil counts, associated with increased concentrations of cortisol and catecholamines, indicated that stress was maximal upon arrival. At this time, a decrease in the percentages of all T lymphocyte subsets was evident, while they did not decrease as absolute counts. The proportion of CD21(+) cells did not change, indicating that the relative reduction of T lymphocyte subsets was not related to an increase in B lymphocytes. These variations may be due to the increase of a natural killer (NK) cell subset. NK cell expansion, together with increasing lymphocyte count and increasing major histocompatibility complex class II expression, may indicate stress-induced stimulation of the immune system.     

The effect of temperature and humidity on longevity of metacercariae of Fasciola gigantica

Studies were undertaken on the viability of the metacercariae of Fasciola gigantica when stored in water at 13^˚C for periods up to 23 weeks, exposed to the sunlight for up to 8 h or stored at a range of temperatures and humidities for up to 10 weeks. Excysted metacercariae were catergorized microscopically as viable (motile and undamaged), dubious (not motile and undamaged) or dead (visible necrosis). The infectivity of viable and dubious metacercariae and unselected reference metacercariae held in water at 7^˚C for 20 days or longer was assessed by comparing numbers of flukes recovered from infected Merino sheep. Mean recovery rates were 54.6%, 7.2% and 37.2%, respectively, for viable, dubious and unselected metacercariae. Metacercariae immersed in water remained viable longer than those allowed to desiccate. Viability was promoted by decreasing temperature and increasing humidity. Exposure to direct sunlight killed metacercariae within 8 h. Results indicated that in lowland Indonesian irrigated rice paddies, metacercariae immersed in water are likely to survive for less than 5 weeks while those that become desiccated will survive less than 2 weeks. This information, together with the option of exposing fresh rice stalks to direct sunlight before feeding them to livestock, can assist farmers in reducing infection with F. gigantica.     

Morphology and life cycle of Apatemon hypseleotris species novum from Australia including metacercariae viability and excystment

Experimental infection of pigeon squabs and rats with encysted metacercariae from the Western Carp gudgeon (Hypseleotris klunzingeri) showed them to be infected with a new strigeid trematode, Apatemon hypseleotris. Growth and development of A. hypseleotris in pigeons were significantly higher than in rats. Eggs appeared in pigeon faeces within 7-14 days; miracidia hatched within 15-21 days and in the snail Lymnaea tomentosa released within 21 days. Cercariae experimentally encysted in the leeches Helobdella papillornata (86.7%) and Alboglossiphonia australiensis (73.3%). In fish, encystation occurred in the abdominal cavity (100%) and muscles (40%) of Hypseleotris klunzingeri, in the abdominal cavity (80%) and head (30%) of Gambusia affinis and in the abdominal cavity (62.5%) of Oncorhynchus mykiss but no encystation occurred in Moenkhausia pittieri. Freezing (-7 degrees C for 3-7 days or -21 degrees C for 8-12 hours), chilling (6 degrees C for 12 days), boiling (3 minutes) or salting for 3-5 days of encysted metacercariae did not significantly reduce infectivity. In vitro excystation of metacercariae was achieved using pepsin followed by trypsin and/or bile salts.     

Longevity of Bolbophorus damnificus infections in channel catfish

The digenean Bolbophorus damnificus infects commercial channel catfish Ictalurus punctatus, causing mortality, lower feed consumption, and reduced growth in surviving fish. The purpose of this study was to determine the length of time for which B. damnificus prodiplostomulum metacercariae (juvenile trematode stage that infects fish) would remain viable (parasite appearing to be intact or exhibiting movement) in channel catfish. Fish (n = 210) were infected with molecularly confirmed B. damnificus cercariae harvested from naturally infected marsh rams-horn snails Planorbella trivolvis. During the first sampling (at 20 d postinfection), 8.3 +/- 3.6 metacercariae/fish (mean +/- SD) were found in the host muscle and visceral organs. The channel catfish were then acclimated to a water temperature of either 18 degrees C or 28 degrees C. After 11 months, 6.8 +/- 3.5 and 5.9 +/- 3.0 metacercariae/fish were found in groups held at 18 degrees C and 28 degrees C, respectively. The mean number of parasites per fish did not significantly differ between fish held at the two temperatures and did not significantly decline over time at either temperature. Fish examined from 13 to 30 months postinfection all contained viable metacercariae that were morphologically and molecularly identified as B. damnificus. At 18 months, 12 metacercariae (of which 11 were intact and 10 displayed movement) were found in the one fish sampled; at 30 months, the last fish sampled contained three intact metacercariae (one displayed slight movement). Our results indicate that B. damnificus metacercariae can remain viable in channel catfish for at least an 18-30-month production cycle during which they have the potential to affect fish growth; in addition, infected fish may serve as intermediate hosts for these metacercariae for at least 2.5 years postinfection.     

Local temperature and El Niño Southern Oscillation influence migration phenology of East Asian migratory waterbirds wintering in Poyang,China

Temperature is a critical factor influencing avian phenology, due to its direct impact on food and water availability. Most previous studies have focused on the timing of spring migration and the arrival of birds at breeding grounds along the European and American flyways; little is known about migration ecology at the wintering sites along the Asian flyways. Using linear regression models, this study investigates how local temperature variation and EI Niño Southern Oscillation (ENSO) influences the arrival and departure timing of 9 waterbird species breeding in Mongolia or Siberia and overwintering in Poyang, China from 2002 to 2013. Birds mainly arrive at Poyang in October and depart for their breeding sites in March. Out of the 9 species, 6 show a strong negative relationship between departure time and overwintering temperature in Poyang. Departure dates also show a negative association with overwintering ENSO and March ENSO for two species. Both local and large‐scale climate indices show no influence on the arrival timing of waterbirds. We suggest that birds react to the annual variation of overwintering temperature: an earlier departure of waterbirds is facilitated by a warmer overwintering period and vice versa. The long‐term accumulated temperature effect is more pronounced than ENSO and the short‐term local temperature effect. Our findings could help quantify the potential impact of global warming on waterbirds.     

The Use of an Immunomodulator to Enhance the Reproductive Performance of Gilts Transported for Long Distances from Breeding to Commercial Units

Contents
The reproductive performance of gilts transported for long distances from three high-health breeding farms to six commercial farms was tested after the use of a Parapox-ovis-virus-based immunomodulator, Baypamun N (Bayer AG, Germany). Sixty (60) gilts were injected with Baypamun N, three times (2 days before departure, 2 h before departure and 2 days after their arrival at the commercial farms), while the remaining 60 gilts were injected with placebo at the same times. The results indicated that: (i) no adverse reactions or adverse effects were noticed related to the treatment with Baypamun N, (ii) treatment with Baypamun N improved the reproductive performance of gilts; the proportion of gilts farrowed/total gilts examined, the total number of piglets born, the number of piglets born alive and the body-weight of piglets at farrowing were significantly increased (p < 0.05), and (iii) treatment with Baypamun N reduced (p < 0.05) the cost of medication per gilt examined and per served gilt.     

PRODUCTION EFFECTS OF LIVER FLUKE (FASCIOLA HEPATICA) INFECTION IN BEEF CATTLE

SUMMARY Young Hereford steers of even body weights were grazed on pasture at 2 levels of stocking rate and artificially infected with 0, 600 or 1,200 metacercariae of Fasciola hepatica. In addition all groups obtained a low grade natural infection. Steers were slaughtered at intervals throughout the 32-week trial period and total fluke counts obtained. Fluke counts were significantly higher in all artificially infected groups when compared to the natural infection alone groups with the exception of the 600 metacercariae group during the 12 to 32-week analysis period. There were no significant differences between counts in steers in the 2 nutritional regimes. Rates of growth were significantly reduced by 14.7% and 14.1% in steers receiving a superimposed artificial infection rate of 1200 metacercariae and grazed at 3.54 beasts/hectare and 4.39 beasts/hectare respectively. Similarly group body weights were depressed 3% and 20% in steers receiving 600 metacercariae and grazed at 3.54 beasts/hectare and 4.39 beasts/hectare respectively. There was a significant interaction between level of nutrition and size of artificial infection on body weight changes in the first 12-week period.     

Heterologous resistance to Fasciola hepatica conferred upon rats by passive transfer of serum from different breeds of sheep

Two experiments compared the protection against oral challenge with 20 metacercariae of Fasciola hepatica conferred on rats by intraperitoneal injection of serum from three breeds of sheep infected with F. hepatica (Barbados Blackbelly, St. Croix, Florida Native). Experiment 1 used serum from sheep 5-6 months of age following two infections of 250 metacercariae each, while Experiment 2 utilized serum collected from the same sheep at 10-11 months of age following either a primary (first exposure) or challenge (after two previous exposures of 250 metacercariae each) infection with 500 metacercariae. Similar numbers of flukes were recovered from rats given either immune or nonimmune (control) serum from each breed of sheep in Experiment 1. In Experiment 2, rats given serum from infected St. Croix sheep had significantly fewer flukes than rats given either control or immune serum from Barbados Blackbelly or Florida Native sheep. There was no significant correlation of fluke counts between individual serum donors (sheep) and serum recipients (rats).     

A comparison of florfenicol and tilmicosin for the treatment of undifferentiated fever in feedlot calves in western Canada

A field trial was performed under commercial feedlot conditions in western Canada to compare the efficacy of florfenicol and tilmicosin for the treatment of undifferentiated fever (UF) in calves that received metaphylactic tilmicosin upon arrival at the feedlot. One thousand and eighty recently weaned, auction market derived, crossbred beef calves suffering from UF were allocated to one of 2 experimental groups as follows: florfenicol, which was intramuscular (i.m.) florfenicol administered at the rate of 20 mg/kg body weight (BW) at the time of allocation (Day 0) and again 48 h later, or tilmicosin, which was subcutaneous (s.c.) tilmicosin administered once at the rate of 10 mg/kg BW on day 0. Five hundred and forty-four animals were allocated to the florfenicol group and 536 animals were allocated to the tilmicosin group. The chronicity, wastage, overall mortality, and bovine respiratory disease (BRD) mortality rates were significantly (P < 0.05) lower in the florfenicol group than in the tilmicosin group. There were no significant (P > or = 0.05) differences in first UF relapse, second UF relapse, hemophilosis mortality, or miscellaneous mortality rates between the florfenicol and tilmicosin groups. Average daily gain (ADG) from arrival at the feedlot to the time of implanting and ADG from allocation to the time of implanting were significantly (P < 0.05) lower in the florfenicol group as compared with the tilmicosin group. There were no significant (P > or = 0.05) differences in arrival weight, allocation weight, implanting weight, or ADG from arrival to allocation between the experimental groups. In the economic analysis, there was an advantage of $18.83 CDN per animal in the florfenicol group. The results of this study indicate that florfenicol is superior to tilmicosin for the treatment of UF because of lower chronicity, wastage, overall mortality, and BRD mortality rates. However, interpretation of these observations must take into consideration the fact that these calves received meta-phylactic tilmicosin upon arrival at the feedlot, which is a standard, cost-effective, management procedure utilized by feedlots in western Canada.     

Evaluation of sodium carboxymethylcellulose for prevention of experimentally induced abdominal adhesions in ponies

Twelve ponies were used to evaluate the reliability of an abdominal adhesion model and the efficacy of intraperitoneal infusion of sodium carboxymethylcellulose in preventing abdominal adhesions. A celiotomy was performed on each of the 12 ponies and the serosa of the distal portion of the jejunum was abraded with a dry gauze sponge at 5 locations. In addition to the serosal damage, a single 2-0 chromic gut suture was placed through the seromuscular layer of the jejunum in the center of the abraded area. After closure of the celiotomy, a 1% solution of sodium carboxymethylcellulose (7 ml/kg of body weight) was infused into the peritoneal cavity of 6 ponies. The other ponies served as untreated controls. All ponies were euthanatized 14 days after surgery. All ponies in the control group had abdominal adhesions at the time of necropsy. Four of the 6 ponies in the treatment group were free of adhesions. There was a significant (P less than 0.0001) difference in the total number of adhesions between the 2 groups.     

一种用于腹腔手术机器人测试的巴马猪麻醉方案

为满足手术机器人腹腔手术效果和安全性的测试,建立相应的巴马猪麻醉方案.以低剂量舒泰和高剂量多咪静作诱导麻醉剂,异氟烷作维持麻醉剂,布托啡诺作术中镇痛剂,安定醒作苏醒剂.用手术机器人分别进行胆囊切除、左肾摘除、部分肝切除手术,于整个麻醉过程监测巴马猪心率、血氧饱和度、平均动脉压及体温的变化,以评估该方案的麻醉效果.结果显...     

Characterisation of the pig acute phase protein response to road transport

The acute phase protein (APP) response was evaluated after prolonged transportation of pigs under commercial conditions. Elevated serum APP concentrations were observed in two groups of boars immediately after their arrival at a destination farm compared with within-animal control samples obtained one month later. The effect was more pronounced in the first group of pigs conveyed under average transport conditions (Transport 1, 24 h), although the second group was transported for a longer time period (Transport 2, 48 h) but in superior transport conditions. In a second trial, pigs were sampled before transport, on arrival at an abattoir (following 12 h transport), and at the slaughter-line (after 6 h lairage). Significant increases in major acute phase protein (Pig-MAP), haptoglobin, serum amyloid A, C-reactive protein, and a decrease in apolipoprotein A-I, were observed at slaughter. The results demonstrate that shipment of pigs by road can result in an APP response that is probably related to the stress of transport.     

Systemic effects of topical and subconjunctival ophthalmic atropine in the horse

OBJECTIVE: To identify any systemic effects of topical and subconjunctival administration of atropine sulfate in the horse. Animals studied Six mature grade horses were treated hourly in one eye with topical ophthalmic atropine drops for 24 h. Five horses were treated subconjunctivally in one eye with 3 mg of atropine sulfate. Procedures Pupillary light reflexes, pupil size, electrocardiographic parameters, girth measurements, intestinal motility, and clinical signs of abdominal pain were monitored. RESULTS: Alteration in auscultated gut motility and clinical signs of abdominal pain were the most sensitive indicators of the systemic manifestations of the topically applied atropine. Gut motility was absent in all horses for periods of 2-18 h in all four abdominal quadrants in horses given topically administered atropine. Signs of abdominal pain were observed in four of six horses that received topical atropine. In the subconjunctival test study, gut motility was absent in three horses for periods of 3-7 h. Uniocular subconjunctival injection of 3 mg atropine sulfate produced signs of abdominal pain in one of six horses. Conclusion The ophthalmic administration of atropine can affect gut motility and induce signs of colic in selected horses.     

Protection against Fasciola gigantica infection in rats administered metacercarial antigens

Immature worms were recovered from the liver parenchyma of rats which received extracts of metacercariae or adult worms of Fasciola gigantica, after challenge infection. When resistance was assessed by counting the number of immature worms, exposure of the animals to extracts of these two stages of the flukes conferred a significant degree of protection against challenge with F gigantica metacercariae. Rats given the extract of metacercariae were more resistant to infection than rats immunised with the extract of adult worms.