Production and immunological responses associated with controlled-release-capsule vs 5-drench preventive anthelmintic programmes for parasite control in lambs

AIMS: To determine whether: a) using a controlled-release anthelmintic capsule (CRC) instead of a programme of 5 oral drenches administered at 3-4 week intervals, would delay the development of anti-parasite immunity in lambs; b) the use of ivermectin instead of albendazole, administered either as a CRC or as a programme of 5 oral drenches, would delay the development of anti-parasite immunity in lambs; c) lambs treated with CRCs would have higher liveweight gains than lambs drenched orally 5 times at 3-4 week intervals, and; d) delayed onset of anti-parasite immunity is associated with reduced liveweight gains in the period following anthelmintic treatment. METHODS: Three field trials were conducted, 1 on a research farm and 2 on commercial sheep farms, in which groups of 30 lambs were treated with either a CRC containing albendazole, a CRC containing ivermectin, 5 oral drenches with albendazole, or 5 oral drenches with ivermectin, administered at 3-4 week intervals. Liveweights and faecal nematode egg counts (FECs) were recorded in all trials. Immunoglobulin-G (IgG) antibody levels to Ostertagia circumcincta and Trichostrongylus colubriformis adult and larval antigens were measured in Trials 1 and 3, and fleece weights and resistance of animals to nematode challenge infection were measured in Trial 1. RESULTS: CRC-treated lambs had higher levels of antibodies to O. circumcincta infective-stage larvae (L3) than orally drenched lambs in Trial 3, but no other immunological differences due to mechanism of delivery were detected. Antibody levels were lower in lambs treated with ivermectin than albendazole, as a CRC or oral drench in Trial 1, but this was not associated with any measurable effects on FEC or productivity. No significant differences (p>0.05) were detected between drench types (albendazole vs ivermectin) or delivery mechanisms (CRC vs oral drenching) in any of the production parameters measured, in any of the trials. Albendazole-CRCs failed to control FECs in all 3 trials. CONCLUSIONS: Although some differences between treatments in antibody levels were detected these were not associated with measurable differences in level of parasitism or productivity of lambs. CRC use did not appear to offer substantial gains in productivity over a structured programme of 5 oral drenches administered at 3-4 week intervals.     

Pectus excavatum and left to right intracardiac shunt in a kitten

A six-week-old female kitten presented for severe pectus excavatum. Surgical correction was performed. One week later the kitten developed dyspnoea and a systolic murmur was detected on thoracic auscultation. Pulmonary oedema and cardiomegaly were identified radiographically, and a left to right intracardiac shunt was visualized using non-selective angiocardiography. Clinical signs resolved spontaneously one month later. The kitten has been asymptomatic for 24 months.     

Bovine spongiform encephalopathy: epidemiological studies on the origin.

The results of further epidemiological studies of bovine spongiform encephalopathy (BSE) support the previous findings that the onset of exposure of the cattle population to a scrapie-like agent, sufficient to result in clinical disease, occurred in 1981/82. The onset of this exposure was related to the cessation, in all but two rendering plants, of the hydrocarbon solvent extraction of fat from meat and bone meal. A further possible explanation, related to the geographical variation in the reprocessing of greaves to produce meat and bone meal, was identified for the geographical variation in the incidence of BSE.     

Effect of Insemination–Ovulation Interval and Addition of Seminal Plasma on Sow Fertility to Insemination of Cryopreserved Sperm

In swine, the use of frozen-thawed (FT) sperm for artificial insemination (AI) is limited because of poor sow fertility, possibly associated with a post-thaw capacitation-like status resulting in fewer fully viable sperm. Sow fertility to AI with FT sperm may improve with deeper deposition of sperm within the female tract, insemination very close to ovulation, or reversal of cryocapacitation by seminal plasma (SP). We performed two experiments to examine these suggestions. In experiment 1, 122 multiparous Yorkshire sows received 600 IU equine chorionic gonadotrophin at weaning and 5 mg pLH 80 h later to control time of ovulation. The predicted time of ovulation (PTO) was 38 h after pLH injection. Thereafter, sows were assigned on the basis of parity to a single AI of FT sperm at 2 h before PTO, or at 12 h before PTO, or FT sperm supplemented with 10% SP at 12 h before PTO. Control sows received fresh semen at 12 h before PTO. All semen doses were adjusted to 3 x 10(9) live cells and deposited into the cervix. Experiment 2 employed 99 multiparous crossbred sows and repeated the treatments of experiment 1 except that all FT inseminations were intrauterine. In both experiments, farrowing rates were lower (p < 0.01) following FT inseminations with no effect of time of insemination or of supplemental SP. In experiment 1, litter size was smaller following FT insemination (p < 0.05), but no effect on litter size was evident in experiment 2. Supplemental SP had no effect on litter size in either experiment. The lack of effect of either SP or timing of FT insemination on sow fertility suggests that the non-lethal sperm cryoinjury affecting fertility involves more than just cryocapacitation.     

Comparison of carprofen and butorphanol as post-surgical analgesics in cats

Post‐operative pain management by a single subcutaneous (SC) injection of carprofen has been found to be effective in cats and dogs. This clinical study compared the analgesic properties of injectable carprofen and butorphanol in 71 healthy cats (0.5–5 years, mean weight 3.24 ± 0.61 kg) undergoing ovariohysterectomy. Cats were randomly assigned to three groups: Group C received carprofen 4 mg kg^?1 SC at intubation and sterile saline 0.08 mL kg^?1 SC at extubation; Group B received sterile saline 0.08 mL kg^?1 SC at intubation and butorphanol 0.4 mg kg^?1 SC at extubation; Group S received sterile saline 0.08 mL kg^?1 SC at intubation and extubation. All cats were pre‐medicated with atropine (0.04 mg kg^?1 SC), acepromazine (0.02 mg kg^?1 SC), ketamine (5 mg kg^?1 SC), and induced IV with ketamine (5 mg kg^?1) and diazepam (0.25 mg kg^?1). Serum biochemistry values were taken at 24 and 48 hours post‐surgically and compared to a pre‐surgical baseline. Behavioral data were collected by a blinded investigator prior to surgery (baseline) and 1, 2, 3, 4, 8, 12, 16, 20, and 24 hours post‐surgery; the data were compiled into composite pain scores on a scale from 0 to 21 and complemented by visual analogue scores (VAS). Scoring was based on changes in behavior, posture, vocalization, and response to interactive stimulation. Cats with pain scores >12 were considered to be moderately painful, received meperidine (4 mg kg^?1 IM), and were excluded from further statistical analyses. Sixty of 71 cats completed the study. Anesthetic time was 88.5 ± 21.8 minutes (mean ± SD). Meperidine was given to one cat in C, three in B, and five in S. There were no significant differences in biochemistry values. There were no significant differences in pain scores between C and B at any time period; B and C pain scores were significantly lower than S at 1, 2, 12, 16, and 20 hours post‐operatively, and C lower than S at 3 and 8 hours post‐surgery. Pain scores decreased over the 24‐hour study in all groups; the greatest decrease in each group was between 4 and 8 hours post‐operatively. In this study, carprofen provided post‐surgical analgesia comparable to butorphanol.     

Multifunctional carbon nanotube yarns by downsizing an ancient technology

By introducing twist during spinning of multiwalled carbon nanotubes from nanotube forests to make multi-ply, torque-stabilized yarns, we achieve yarn strengths greater than 460 megapascals. These yarns deform hysteretically over large strain ranges, reversibly providing up to 48% energy damping, and are nearly as tough as fibers used for bulletproof vests. Unlike ordinary fibers and yarns, these nanotube yarns are not degraded in strength by overhand knotting. They also retain their strength and flexibility after heating in air at 450 degrees C for an hour or when immersed in liquid nitrogen. High creep resistance and high electrical conductivity are observed and are retained after polymer infiltration, which substantially increases yarn strength.     

Effects of meloxicam or tolfenamic acid administration on the pain and stress responses of Merino lambs to mulesing

OBJECTIVE: To determine the effectiveness of two long-acting non-steroidal anti-inflammatory drugs (NSAIDs) at reducing the pain and stress responses to mulesing in lambs. PROCEDURES: Merino lambs (n = 60) were allocated at 5 weeks of age to six treatment groups: (1) sham mules; (2) mules; (3) tolfenamic acid-sham mules; (4) tolfenamic acid administered 45 min before mulesing; (5) tolfenamic acid at the time of mulesing; (6) meloxicam at the time of mulesing. Plasma cortisol was measured at -0.75, -0.25, 0, 0.5, 1, 3, 6, 12, 24, 48 and 72 h relative to mulesing. Beta-endorphin concentrations in plasma were determined at 0, 0.5, 1, 6, 12, 24, and 48 h. Haematology was performed on blood samples taken at -0.75, 0, 24, 48 and 72 h. Plasma haptoglobin was measured at 0, 12, 24, 48 and 72 h. Rate of wound healing was determined 72 h post mulesing, and animal behaviour, including posture, was measured for 6 h after mulesing. RESULTS: The mulesed lambs exhibited large increases in plasma concentrations of cortisol, beta-endorphin and haptoglobin. All mulesed animals lost weight significantly in the week after mulesing, regardless of analgesic administration, but the difference in weight between mulesed and unmulesed lambs was less at the final measurement, 2 weeks after mulesing. Mulesed lambs spent significantly less time lying ventrally than control lambs. All lambs that were mulesed, including those administered NSAIDs, spent more time standing with a hunched posture and less time walking normally than control lambs. CONCLUSIONS: The NSAID treatments applied 45 min before or at the time of mulesing at the dose levels used in this study were not effective in reducing the acute response of lambs to mulesing.     

An outbreak of avian malaria in captive yellowheads/mohua (Mohoua ochrocephala)

CASE HISTORY: Eight mohua, or yellowheads (Mohoua ochrocephala), were held in a large open aviary over the summer months of 2003-2004, following their capture for captive breeding purposes. Two birds died of transportation trauma shortly after arrival, one became ill and died a month later, and another four died within a 2-week period in February 2004. The eighth bird also became ill at this time but survived for a year following treatment with chloroquine and doxycycline. CLINICAL AND PATHOLOGICAL FINDINGS: The affected birds were depressed, lethargic and dyspnoeic. Necropsy of three birds showed a slightly pale and swollen liver and spleen. Impression smears of the liver of one bird revealed schizonts resembling Plasmodium spp. within the cytoplasm of many hepatocytes, which was confirmed histopathologically. Similar protozoal organisms were seen within splenic histiocytes and pulmonary endothelial cells of 5/6 birds. Electron microscopy identified these as protozoal schizonts containing merozoites of similar size and structure to those of Plasmodium spp. DIAGNOSIS: The birds were infected with a protozoal haemoparasite resembling Plasmodium spp.; asexual stages within hepatocytes and endothelial cells of the lung and spleen were typical of this organism. CONCLUSIONS AND CLINICAL RELEVANCE: The mohua captured from west Otago were highly susceptible to avian malaria as they came from an isolated population that was likely to be na?ve and have had no previous contact with this organism. The birds were probably infected by bites from mosquitoes feeding off local populations of blackbirds subsequently found to be infected with Plasmodium spp.