Derivation, safety and efficacy of a Marek's disease vaccine developed from an Australian isolate of very virulent Marek's disease virus     

RC KARPATHY  GA FIRTH  GA TANNOCK 《Australian veterinary journal》2002,80(1):61-66

Objective To develop a serotype 1 Marek's disease (MD) vaccine from a very virulent MDV (vvMDV) pathotype and demonstrate safety and efficacy against early challenge with very virulent field strains in the presence of maternal antibody.
Study design Strain BH 16 was isolated and attenuated by serial cell culture passage. One of two cloned passages was selected for vaccine development following early laboratory-scale protection trials in commercial birds. Comparative protection trials were carried out on the BH 16 vaccine and on a CVI 988 Rispens vaccine using commercial and SPF chickens. Challenge viruses used were either a low passage strain BH 16 virus, the Woodlands No. 1 strain or MPF 57 strain of MDV. The BH 16 vaccine was back-passaged in SPF chickens six times and virus recovered from the final passage and the original vaccine virus were tested for safety. The immunosuppressive potential of the BH 16 and Rispens vaccines was also assessed in parallel.
Results The BH 16 and Rispens vaccines induced comparable levels of protection when used as monovalent or multi-valent vaccines, although protection achieved with the mono-valent vaccines was lower. No gross tumour formation was evident in any birds receiving the BH 16 vaccine or bird-passaged virus, although microscopic lesions were present in 2/12 birds that received the bird-passaged virus. In tests for immunosuppression, there was no histological evidence of damage to either the bursa of Fabricius or the thymus.
Conclusion The BH 16 vaccine was shown to be safe and at least as protective as the Rispens vaccine against three highly virulent MD challenge viruses.  相似文献   

Optic nerve hypoplasia in miniature poodle dogs: A preliminary genetic and candidate gene association study     

Doreen Becker  Jessica K. Niggel  Sue Pearce‐Kelling  Ronald C. Riis  Gustavo D. Aguirre 《Veterinary ophthalmology》2020,23(1):67-76

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沙棘叶水提物适应原性及安全性评价     

花圣卓  王宏昊  滕晓萍  温中平  Banerjee PK  Kumar R 《国际沙棘研究与开发》2011,(2):39-48

本文评估了沙棘叶水提物在大白鼠体内的适应原活性和毒性.提取物的剂量依赖性适应原活性的研究采取将小鼠置于低温(5℃),低压(428mmHg),抑制(C-H-R)的环境下的30min前口服不同剂量的沙棘叶水提物.在亚急性毒性中,连续14d每天口服10倍和20倍最大有效剂量（每天口服1g/kg体重和2g/kg体重）和连续30...  相似文献   

Amounts and Variation of Soluble Collagen in Mink Skin During Growth from Kits to Adult Animals     

Bent Riis 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(4):225-230

The soluble collagen from mink skin was extracted from 2-week to 6-month-old animals. A total of 14 different age groups, each containing three animals, was studied by using two different buffers for collagen extraction. The amount of soluble collagen was measured. The various collagen species were characterized using capillary zone electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein blotting followed by antibody analysis for type I collagen. The data showed that the amount of soluble collagen declines with age. Using capillary electrophoresis it was also found that the distribution of soluble collagen differs in very young kits' skin compared with older animals' skin, whereas the skin from animals more than 2 weeks old was found to contain the same proportions of various collagen species. Antibody analysis of type I collagen found no difference in the relative amount between different age groups, and only the acetic acid-containing buffer extracted type I collagen from the mink skin.  相似文献   

Effect of displaced versus non‐displaced pelvic fractures on long‐term racing performance in 31 Thoroughbred racehorses     

SE Hennessy  MA Muurlink  GA Anderson  TN Puksmann  RC Whitton 《Australian veterinary journal》2013,91(6):246-250

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Increased yearling weight as a proportion of 21-month weight was associated with increased milk production in dairy heifers     

RC Handcock  N Lopez-Villalobos  LR McNaughton  PJ Back  GR Edwards  RE Hickson 《New Zealand veterinary journal》2020,68(5):272-282

ABSTRACT

Aims: To examine the relationship between liveweight (LWT) at 12 months as a proportion of LWT at 21 months of age (LWT(12/21)%) and first lactation and cumulative 3-year milk production in dairy heifers in New Zealand.

Methods: Liveweight and milk production records were obtained for dairy heifers born from June to December (spring-calving season) between 2006–2007 and 2013–2014 dairy seasons; production records included first lactation (n?=?140,113) and cumulative 3-year (n?=?67,833) milksolids and energy-corrected milk (ECM) yields. Heifers were classified into five breed groups; Holstein-Friesian, Holstein-Friesian crossbred, Jersey, Jersey crossbred and Holstein-Friesian-Jersey crossbred. Within each breed group heifers were categorised into quintiles based on 21-month LWT. The LWT(12/21)% was calculated for each animal. Relationships between LWT(12/21)% and milk production within each breed group and LWT category were estimated using linear mixed effects models including the linear and quadratic effects of LWT(12/21)%.

Results: The relationship between LWT(12/21)% and milk production was predominantly curvilinear, with lower milk production at lesser LWT(12/21)% compared with greater LWT(12/21)%. For all breed groups and most LWT categories, heifers that were 55 or 65% LWT(12/21)% produced greater ECM and milksolids yields compared with heifers that were 45% LWT(12/21)%. Holstein-Friesian, Holstein-Friesian crossbred and Holstein-Friesian-Jersey crossbred heifers that were 65% LWT(12/21)% produced greater cumulative 3-year ECM and milksolids yields compared with heifers of the same breed group that were 45% LWT(12/21)%

Conclusions and clinical relevance: Heifers that were a greater proportion of their 21-month LWT at 12 months of age produced more first lactation and cumulative 3-year milk yields than heifers that were a lesser proportion of their 21-month LWT at 12 months of age. These results indicate that increased growth in early life of New Zealand dairy heifers is beneficial to future milk production.  相似文献   

Prevalence of subchondral bone pathological changes in the distal metacarpi/metatarsi of racing Thoroughbred horses          下载免费PDF全文

E Bani Hassan  M Mirams  EJ Mackie  RC Whitton 《Australian veterinary journal》2017,95(10):362-369

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Management Strategies Aiming to Improve Horse Welfare Reduce Embryonic Death Rates in Mares          下载免费PDF全文

E Malschitzky  AM Pimentel  P Garbade  MIM Jobim  RM Gregory  RC Mattos 《Reproduction in domestic animals》2015,50(4):632-636

The objective of this retrospective study was to evaluate the effect of management strategies aiming to improve animal well‐being on pregnancy and embryonic death (ED) rates. Breeding records of a cohort of 1206 Thoroughbred mares brought to a stallion station facility, to be bred with the stallions housed there, were evaluated during ten breeding seasons. Mares were blocked according to management strategies in two groups: Stress and Relax. Strategies used to improve animal well‐being (Relax group) were as follows: stopping the teasing routine, reducing or eliminating stall confinement, reducing the number of mares per group and maintaining herd stability during the breeding season. In barren mares, the pregnancy rate was higher in the Relax group (91.8%) when compared to the observed in Stress group (84.7%). However, no difference in pregnancy rates were observed (Stress = 85.2% vs. Relax = 86.2) in foaling mares. ED rate was higher in barren and foaling mares of the Stress group mares (25.5% and 26.8%, respectively) compared with the Relax group (16.1% and 14.7%, respectively). No significant differences were observed on foal heat pregnancy rate between groups; yet, the embryo loss on foal heat was significant reduced in Relax mares (Relax = 8.7% vs Stress = 24.5%). In conclusion, management strategies aimed to reduce social stress can reduce early pregnancy losses and the average cycles per pregnancy, improving reproductive performance in mares.  相似文献   

Restoration of a Danish headwater stream: short‐term changes in plant species abundance and composition     

Annette Baattrup‐Pedersen  Tenna Riis  Hans Ole Hansen  Nikolai Friberg 《水产资源保护:海洋与淡水生态系统》2000,10(1):13-23

1. This paper describes the short‐term effects (2 years) of stream restoration on vascular plant communities in a 1.4 km upper reach of the River Gudenå, Denmark. The effects of restoration were assessed in terms of the abundance and composition of plant species in the stream, on the banks and in the stream valley. 2. Total species richness was similar before and after restoration, and comprised approximately 150 species representing 12% of the entire Danish vascular plant flora. 3. In the stream, total plant cover had not recovered to pre‐restoration levels 2 years after restoration. Cover by submerged, amphibious and terrestrial species growing submerged decreased, as did the number of amphibious and terrestrial species growing submerged. 4. On the banks, total plant cover almost attained pre‐restoration levels the second year after restoration. The plant communities changed from dominance by non‐riparian species to more diverse communities with a greater number and increased cover of riparian gramineous species requiring a higher soil moisture content. 5. In the valley, the plant communities only changed slightly after restoration, although growth of riparian species was enhanced on the southern side of the stream. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Elasticity of single-crystal MgO to 8 gigapascals and 1600 kelvin     

G Chen  RC Liebermann  DJ Weidner 《Science (New York, N.Y.)》1998,280(5371):1913-1916

The cross pressure (P) and temperature (T) dependence of the elastic moduli (Cij) of single-crystal samples of periclase (MgO) from acoustic wave travel times was measured with ultrasonic interferometry: partial differential2C11/ partial differentialP partial differentialT = (-1.3 +/- 0.4) x 10(-3) per kelvin; partial differential2C110/ partial differentialP partial differentialT = (1. 7 +/- 0.7) x 10(-3) per kelvin; and partial differential2C44/ partial differentialP partial differentialT = (-0.2 +/- 0.3) x 10(-3) per kelvin. The elastic anisotropy of MgO decreases with increasing pressure at ambient temperature, but then increases as temperature is increased at high pressure. An assumption of zero cross pressure and temperature derivatives for the elastic moduli underestimates the elastic anisotropy and overestimates the acoustic velocities of MgO at the extrapolated high-pressure and high-temperature conditions of Earth's mantle.  相似文献