Maiden heifers and lactating cows of known ovarian status and of several breeds were treated with a synthetic prostaglandin, cloprostenol, or a synthetic progestagen, norgestomet, at the start of an artificial insemination (AI) program. Animals in the cloprostenol treatment received 2 injections 10 days apart. Over the next 26 days those animals that showed oestrous behaviour were inseminated. Synchronisation rates and calving rates to insemination over the first 7 days were calculated. Those in the norgestomet treatment received an implant of norgestomet plus an injection of norgestomet and oestradiol valerate. The implant was removed 10 days later and the animals were given an injection of pregnant mare serum gonadotrophin (PMSG). They were inseminated at 48 h (maiden heifers) or 56 h (lactating cows) after implant removal. Calving rates to fixed-time insemination were recorded. After completion of the AI program the animals in both treatments were joined with bulls. Overall calving rates (AI plus bulls) were calculated. By day 7 of the program, 82% of the maiden heifers and 76% of the lactating cows in the cloprostenol treatment had been detected in oestrus. By day 21 the respective figures were 99% and 81% Norgestomet treatment had an immediate and a prolonged effect on ovarian activity in those females classified as having inactive ovaries at the start of the AI program. Calving rates of those females to fixed-time AI and overall were similar to those of the females with active ovaries in both treatments. Their calving rates to fixed-time insemination, and overall calving rates for the lactating females, were significantly higher than the corresponding values of their contemporaries treated with cloprostenol and inseminated on observed oestrus over 7 days. For those females classified as having active ovaries at the start of the AI program, calving rates to first insemination and overall were similar for both treatments. Overall calving rates of lactating cows of each breed were, with one exception, higher in the norgestomet treatment than in the cloprostenol treatment. Although norgestomet treatment was more expensive than cloprostenol treatment, the advantage in calf crop resulted in an overall monetary advantage to the norgestomet treatment. 相似文献
AbstractAIM: To evaluate resistance to anthelmintics containing abamectin, levamisole, and oxfendazole (AB-LEV-OX), derquantal and abamectin (DEQ-AB), moxidectin, and monepantel in naturally acquired gastrointestinal nematodes present on a sheep farm.METHODS: Faecal nematode egg count reduction tests (FECRT) were carried out on lambs that were approximately 7 months-old and infected with naturally acquired nematodes. Lambs were randomly allocated to one of five groups (n=15 per group): treatment with 2?mg/kg derquantel and 0.2?mg/kg abamectin; 0.2?mg/kg abamectin, 8?mg/kg levamisole HCl and 4.5?mg/kg oxfendazole; 2.5?mg/kg monepantel; 0.2?mg/kg moxidectin, or no treatment. Post-treatment samples were collected 12 days later. Abomasa and small intestines were collected from two slaughtered lambs from each of the DEQ-AB, AB-LEV-OX, moxidectin and control groups 15 days after treatment, for nematode counting.RESULTS: The FECRT demonstrated that efficacy was 90.3 (95% CI=84.2–94.1)% for AB-LEV-OX, 54.5 (95% CI=28.4–71.1)% for moxidectin, 99.2 (95% CI=97.4–99.8)% for DEQ-AB and 100% for monepantel, across all genera. For Trichostrongylus spp. efficacy was 85.5% for AB-LEV-OX and 46.7% for moxidectin. Haemonchus spp. were fully susceptible to all treatments. Post-treatment nematode counts indicated that the resistant Trichostrongylus spp. were from the small intestine.CONCLUSIONS: Anthelmintic resistance to both AB-LEV-OX and moxidectin was present in the Trichostrongylus genus on a commercial sheep farm. Monepantel and DEQ-AB were both effective against Trichostrongylus spp. based on FECRT results.CLINICAL RELEVANCE: This finding of resistance to an AB-LEV-OX triple-combination anthelmintic in the Trichostrongylus genus in sheep in New Zealand further limits anthelmintic treatment options available, and calls into question whether this combination is suitable for use as a quarantine treatment. 相似文献
We have determined the first complete genome sequence and capsid gene sequences of feline calicivirus (FCV) isolates from the UK and Australia. These were compared with other previously published sequences. The viruses used in the comparisons were isolated between 1957 and 1995 from various geographical locations and obtained from cats showing a range of clinical signs. Despite these diverse origins, comparisons between all strains showed a similar degree of sequence variation within both ORF1 (non-structural polyprotein) and ORF2 (major capsid protein) (amino acid distances of 7.7-13.0% and 8.8-18.6%, respectively). In contrast, ORF3 (putative minor structural protein) sequences indicated a more heterogenous distribution of FCV relatedness (amino acid distances of 1.9-17.9%). Phylogenetic analysis suggested that, unlike some other caliciviruses, FCV isolates within the current data set fall into one diverse genogroup. Within this group, there was an overall lack of geographic or temporal clustering which may be related to the epidemiology of FCV infection in cats. Analysis of regions of variability in the genome has shown that, as well as the previously identified variable regions in ORF2, similar domains exist within ORFs 1 and 3 also, although to a lesser extent. In ORF1, these variable domains largely fall between the putative non-structural protein functional domains. 相似文献
Aims: To provide herd managers with a set of decision rules allowing them to predict the likelihood that a juvenile bull is ready for Bull Breeding Soundness Evaluation (BBSE), or breeding, if bodyweight and scrotal circumference are known.
Methods: This was a longitudinal study following two groups of young pasture-fed Holstein and Jersey bulls from northwest Tasmania, Australia. Individual scrotal circumference, bodyweight and semen characteristics were recorded at 6–8 weekly intervals, from 6–18 months of age. Classification and regression tree analyses were used to predict the probability that a bull had ≥70% normal sperm morphology based on scrotal circumference and bodyweight measurements.
Results: Overall 1,661 scrotal circumference and bodyweight measurements were obtained, and 518 semen samples from 356 bulls were assessed for sperm morphology, from 16 examination sessions that took place between 29 May 2015 and 17 August 2016. Classification and regression tree analyses generated a decision tree for Holstein bulls with four node endpoints, and for Jersey bulls with three node endpoints. Diagnostic test performance showed that for Holstein bulls, using the node endpoints of scrotal circumference ≥27?cm and bodyweight ≥349?kg, 98% had ≥70% normal sperm (positive likelihood ratio 10.4; 95% CI?=?2.7–41), and using the node endpoints of scrotal circumference ≥27?cm and bodyweight between 282–349?kg, 89% had ≥70% normal sperm (positive likelihood ratio 1.6; 95% CI?=?0.9–2.6). For Jersey bulls, using the node endpoints of bodyweight ≥259?kg and scrotal circumference ≥29?cm, 88% had ≥70% normal sperm (positive likelihood ratio 3.4; 95% CI?=?1.6–7.0).
Conclusions: This study provides a set of relatively simple decision rules based on bodyweight and scrotal circumference measurements that allows herd managers to assess the likelihood that juvenile bulls are ready for BBSE or breeding.
Two depth profiles of the osmium concentration and the 187Os/186Os isotopic ratio in the Indian Ocean showed that the osmium concentration seems to be unaltered by chemical or biological processes occuring in seawater; accordingly, osmium is conservative. These data were obtained from an experimental method that eliminated the problems related to osmium preconcentration. This method led to a new evaluation of the concentration of osmium in seawater; the mean concentration of osmium and the 187Os/186Os ratio are equal to 10.86 +/- 0.07 picograms per kilogram and 8.80 +/- 0.07, respectively. The results suggest the existence of an organocomplex that dominates the speciation of osmium in seawater. 相似文献