Lamb mortality and clostridial disease.

AIMS: To determine the level and timing of lamb loss that occurs during the first year of life on a typical hill country sheep and beef farm in the central North Island of New Zealand and to determine how much of this loss can be prevented through vaccination against the five main clostridial diseases using a commercially available multivalent clostridial vaccine. METHODS: The study was conducted on a single commercial hill country sheep and beef farm in the central North Island of New Zealand, with a history of never vaccinating their stock against clostridial disease. Lambs were blocked on sex and randomly selected at docking into treatment (n = 1,705 lambs) and control (n = 1,709 lambs) groups. Treated lambs were vaccinated at docking and 4 weeks later with 1 mL of multivalent clostridial vaccine. Control lambs were not vaccinated. Different coloured ear tags were used to identify the lambs in the treatment and control groups. All lambs were counted at docking (October 2019) and at six other management event times between docking and when the replacement hoggets were set stocked for lambing (August 2020). The number of lambs sold between each management event, from each group was also counted. The difference in the number of lambs from one management event to another, minus the lambs sold between these events was regarded as the lamb losses for that period. RESULTS: The total percentage of lamb losses from docking to pre-lamb was 4.8% (81/1,705) and 6.2% (106/1,709) in the vaccinated and unvaccinated lambs respectively OR = 0.75 (95% CI = 0.56-1.02; p = 0.06). Most lamb loss occurred in the period after docking, followed by the period between weaning and the first post-weaning drench. Less lamb loss occurred in the vaccinated lambs (27/1,705; 1.6%) after docking than in the unvaccinated lambs (66/1,709; 3.9%). This was mainly due to lower female lamb losses in the vaccinated (5/868; 0.6%) compared to the unvaccinated (38/868; 4.4%) group (p < 0.001). CONCLUSIONS: Vaccination of lambs at docking and 4 weeks later, with a multivalent 5-in-1 clostridial vaccine was associated with a 23.6% (25/106) reduction in total lamb loss from docking to pre-lambing. In female lambs, vaccination was associated with an 87% (33/38) reduction in lamb loss after docking and a 37% (22/59) reduction over the total trial period.

Hepatic expression of polymerase beta, Ref-1, PCNA, and Bax in WY 14,643-exposed rats and hamsters.

The hepatic levels of three protein markers of oxidative stress, polymerase beta, Ref-1, and PCNA, and of the pro-apoptotic protein, Bax, were quantitated after exposure to WY 14,643 (500 ppm in the feed) for 6 or 34 days in a rodent that is susceptible peroxisome proliferator (PP)-induced liver tumors (the Sprague Dawley rat) and in a rodent that is relatively resistant PP-induced liver tumors (the Syrian hamster). The analysis of detergent-extracted whole liver homogenates by immunoblotting showed a marked increase in the abundance of a 45-kDa variant of polymerase beta immunoreactivity and significant increases in the expression of Ref-1 and PCNA in WY 14,643-exposed rats. In contrast. WY 14,643-exposed hamsters expressed only trace levels of the polymerase beta variant and showed significant decreases in the expression of Ref-1 and PCNA. Long-term WY 14,643 exposure was associated with marked decreases in Bax expression in both species. Dose-response studies in the rat showed that the hepatic expression of the polymerase beta and Ref-1 were significantly increased after 6 days of exposure to WY 14,643 at levels of 5 and 50 ppm, respectively. The analysis of subcellular fractions of rat liver showed that the pathological increases in the levels of polymerase beta, Ref-1, and PCNA were especially prominent in mitochondria-enriched particulate liver subfractions. These results indicate that WY 14,643 exposure is associated with an increase in oxidative stress to the liver and that liver mitochondria are a major target of WY 14,643-associated liver damage. Our data are consistent with the hypothesis that the chronic overexpression of mutagenic or oncogenic effectors like polymerase beta and Ref-1 in a setting of increased hepatocyte proliferation and decreased apoptosis may facilitate peroxisome proliferator-induced hepatocellular carcinoma in the rat.

The Medical Journal of Australia Internet peer-review study.

BACKGROUND: Peer review of medical papers is a confidential consultancy between the reviewer and the journal editor, and has been criticised for its potential bias and inadequacy. We explored the potential of the internet for open peer review to see whether this approach improved the quality and outcome of peer review. METHODS: Research and review articles that had been accepted for publication in The Medical Journal of Australia (MJA) were published together with the reviewers' reports on the worldwide web, with the consent of authors and referees. Selected readers' e-mailed comments were electronically published as additional commentary; authors could reply or revise their paper in response to readers' comments. Articles were edited and published in print after this open review. FINDINGS: 60 (81%) of 74 authors agreed to take part in the study, together with 150 (92%) of 162 reviewers. There was no significant difference in the performance of commissioned reviewers before and during the study. Four articles were not included because of insufficient time before print publication. Of the remaining 56 papers, 28 received 52 comments from 42 readers (2% of readers submitted comments). Most readers' comments were short and specific, and seven articles were changed by the authors in response. INTERPRETATION: Open peer review is acceptable to most authors and reviewers. Postpublication review by readers on the internet is no substitute for commissioned prepublication review, but can provide editors with valuable input from individuals who would not otherwise be consulted. Readers also gain insight into the processes of peer review and publication.

Accuracy of pregnancy diagnosis and prediction of calving date in red deer using real-time ultrasound scanning.

One hundred and sixty-two 18-month-old farmed red deer were used to test the accuracy of pregnancy detection and equations for predicting gestational age. Deer ranging from 30 to 110 days gestation were examined by rectal ultrasonography using a 5 MHz transducer while they were standing. Each scan was recorded on video tape for measurements of uterine diameter, amniotic sac diameters, crown-rump length, head length, head diameter, nose length, chest depth, chest width and placentome base-apex length and width. Fetal age was calculated from the mean of the age predictions derived from each dimension measured on individual deer, for 132 deer between 44 and 110 days gestation. All the hinds diagnosed as pregnant produced offspring, and all the hinds diagnosed as not pregnant failed to produce offspring. Between one and six fetal and uterine dimensions were measurable and the number measurable increased with fetal age. The mean error of calving date prediction in 132 deer was 0.97 days. The error of prediction when measurements were made between 44 and 60 days was 0.44 days, whereas between 61 and 80 days and between 81 and 110 days the errors were +0.95 and +4.72 days, respectively. The estimates of calving date were all within 13 days of the calving date.

Real-time ultrasonography for pregnancy diagnosis and estimation of fetal age in farmed red deer.

Twenty-nine farmed red deer hinds two years of age or older were observed during mating in April, and the dates of oestrus and, or, mating were recorded. From May 28 to August 13, at approximately weekly intervals, the deer's uteri and associated structures were examined by rectal ultrasound using a 5 MHz transducer while the deer were held standing in a restraining device. The uterine diameter, amniotic sac diameters, crown-rump length, head length, nose length, chest depth, chest width and placentome base-apex and width were measured for each scan. Quadratic regression equations were computed for each measurement with age, using data from hinds with known mating dates, and the chronological sequence of appearance of a range of uterine and fetal characteristics was recorded. There were significant quadratic regressions. (P less than 0.001) for each of the measurements. The accuracy of pregnancy detection to 117 days after conception was 99.3 per cent and to 132 days after conception 97.4 per cent. The confirmation of non-pregnancy was 96.5 per cent accurate. The regressions of each measurement by age should provide an accurate method for the estimation of fetal age in red deer.