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101.
Genotypic diversity in field isolates of Babesia bovis from cattle with babesiosis after vaccination
AE LEW RE BOCK JM CROFT CM MINCHIN TG KINGSTON RJ DALGLIESH 《Australian veterinary journal》1997,75(8):575-578
Objective To determine whether particular genotypes of Babesia bovis were common to field isolates obtained from cattle properties in Queensland where the B bovis vaccine had apparently failed.
Design A comparative study of polymerase chain reaction genotypes in different populations of B bovis .
Procedure Two polymerase chain reaction assays were applied to analyse DNA extracts of B bovis vaccine (K, T and Dixie strains) and 27 field isolates from 24 properties where disease outbreaks had occurred despite the use of the vaccine. To evaluate the stability of the genotypes identified, 11 of the field isolates were inoculated into experimental cattle that had either been previously vaccinated with T strain or not vaccinated.
Results No particular genotype of B bovis was responsible for the problems observed in previously vaccinated herds. None of the isolates had genotypes identical to the vaccine strains used. No geographic trends among the genotypes were observed. Isolates that originated from the same property also had different genotypes. Blood passage of the 11 field isolates in either previously vaccinated or nonvaccinated cattle did not alter the original genotype.
Conclusion No particular genotypes identified by the Bv80 and BvVA1 polymerase chain reaction assays could be associated with vaccine failures. 相似文献
Design A comparative study of polymerase chain reaction genotypes in different populations of B bovis .
Procedure Two polymerase chain reaction assays were applied to analyse DNA extracts of B bovis vaccine (K, T and Dixie strains) and 27 field isolates from 24 properties where disease outbreaks had occurred despite the use of the vaccine. To evaluate the stability of the genotypes identified, 11 of the field isolates were inoculated into experimental cattle that had either been previously vaccinated with T strain or not vaccinated.
Results No particular genotype of B bovis was responsible for the problems observed in previously vaccinated herds. None of the isolates had genotypes identical to the vaccine strains used. No geographic trends among the genotypes were observed. Isolates that originated from the same property also had different genotypes. Blood passage of the 11 field isolates in either previously vaccinated or nonvaccinated cattle did not alter the original genotype.
Conclusion No particular genotypes identified by the Bv80 and BvVA1 polymerase chain reaction assays could be associated with vaccine failures. 相似文献
102.
A study was conducted to evaluate the effects of postpartum prostaglandin treatment on reproduction in 3 seasonal calving dairy herds. Recently calved lactating dairy cows were paired on herd, age, calving date and previous production index. One cow in each of the 196 pairs received a single intramuscular injection of 25 mg of the prostaglandin analogue, dinoprost, between 14 and 28 days after calving. Subsequent reproduction was monitored. Within each herd and overall, there was no significant effect of treatment on the intervals from calving to first service, mating start date to first service, calving to conception, mating start date to conception and first service to conception. Treatment also had no significant effect on 21-day submission and pregnancy rates, on the proportion of each group not pregnant at the end of mating, and on first service pregnancy rates. Responses to treatment did not vary between cows calving within 50 days of mating start date and earlier calving cows or between cows aged less than 5 years and older cows. 相似文献
103.
C. R. Joiris L. Holsbeek JM. Bouquegneau M. Bossicart 《Water, air, and soil pollution》1991,56(1):283-293
Total Hg levels were determined in 17 harbour porpoises Phocoena phocoena collected in the North Sea and the Kattegat (muscle, liver and kidney), as well as in a sperm whale Physeter macrocephalus, a common dolphin Delphinus delphis and two bottle-nose dolphins Tursiops truncatus collected in Belgium. Juvenile porpoises (total body length less than 140 cm) were characterized by total Hg concentrations increasing with length (t.i. with age) with median values of 3.1 μg g?1 dw in muscle, 6.2 in liver and 5.7 in kidney, and liver to muscle resp. liver to kidney ratios varying between 1 and 2. In adults, liver concentrations were higher (up to 500 μg g?1 dw) with liver to muscle and to kidney ratios up to 20. Median McHg concentrations in 5 of the porpoises were 4.0 μg g?1 dw in muscle and 6.9 in liver. These values did not increase as strongly with length (t.i. with age, at least for juveniles) as total Hg did; as a consequence, the relative McHg levels decreased from 100% in juveniles to 2 or 3 % in the liver of adults. Such results seem to reflect the existence of a slow mineralization phenomenon and storage of inorganic Hg, mainly in the liver. 相似文献
104.
A total of 6195 cattle were enrolled in this observational study. Serum antibody concentrations to bovine herpesvirus 1 (BHV1) and bovine viral diarrhoea virus (BVDV) were measured at entry to and exit from backgrounding facilities to assess their statuses on arrival and the extent of seroconversion to these viruses during backgrounding. The backgrounding facilities were contiguous with five feedlots in: Queensland (two sites), New South Wales, South Australia and Western Australia. Cattle were held in the backgrounding facilities for a minimum of 29 days and a median of 34 days. On backgrounding facility entry, 32.7% of the study population was seronegative to BVDV, but 85.7% was seronegative to BHV1. After commingling in the backgrounding facilities, of the cattle that were seronegative on backgrounding facility entry, 33.9% and 30.3% showed a serological increase to BVDV and BHV1, respectively. At backgrounding facility exit, when cattle were placed in their feedlots, 19.6% and 59.1% were seronegative to BVDV and BHV1, respectively, and 0.26% were persistently infected with BVDV. There was a strong association between seroincrease to BVDV and seroincrease to BHV1 (P = 0.005) at animal level in cohorts known to contain an animal persistently infected with BVDV. 相似文献
105.
106.
107.
SUMMARY The milk production of cows after induced parturition was compared with that of non-induced cows with similar calving dates, in 37 winter-calving, pasture-fed, commercial dairy herds in south-western Victoria. Parturition was induced when most cows were between 27 and 35 weeks of pregnancy. Milk production was compared for the lactation that commenced immediately after induction. The percentage of cows whose lactations were terminated less than 120 days after calving was increased by induction. Mean percentages for untreated and induced groups were 3.0% and 5.4%, respectively . For cows with lactations of at least 120 days duration, lactation length was not affected by the prior induction of parturition. However, milk production during the subsequent lactation was 9.0% less in induced groups. Fat and protein concentrations were not substantially affected. The reduction in milk production was not affected by stage of pregnancy when cows were induced, but tended to be greater in herds that delayed milking of induced cows . 相似文献
108.
109.
A nine-year-old female desexed Great Dane presented with a painful, proliferative, soft red putative neoplastic vascular mass on the nictitating membrane. Three 7-day cycles of the topical cytotoxic drug mitomycin C 0.04%, applied four times daily to the lesion using a low-dose alternate-week pulse therapy, brought about rapid remission of the lesion. The lesion was still in remission at time of euthanasia some 13 months later. 相似文献
110.