Tracking the long-term decline and recovery of an isolated population     

RL Westemeier  JD Brawn  SA Simpson  TL Esker  RW Jansen  JW Walk  EL Kershner  JL Bouzat  KN Paige 《Science (New York, N.Y.)》1998,282(5394):1695-1698

Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.  相似文献   

Establishment and early growth of different plant types of Corsican pine (Pinus nigra var. maritima) on four sites in Thetford Forest     

Jinks  RL; Kerr  G 《Forestry》1999,72(4):293-304

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Suppurative otitis in cattle associated with ear mites (Raillietia auris)     

TF JUBB  RL VASSALLO  RH WROTH 《Australian veterinary journal》1993,70(9):354-355

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Encephalomyocarditis virus infection in pigs     

AR MERCY  RL PEET †  TM ELLIS †  J. PARKINSON † 《Australian veterinary journal》1988,65(11):355-355

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Rhabdomyolysis in housed, fine-woolled merino sheep, associated with low plasma alphatocopherol concentrations     

RL PEET  J. DICKSON 《Australian veterinary journal》1988,65(12):398-399

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Isolation of infectious bronchitis virus from a flock of racing pigeons   总被引：6，自引：0，他引：6  

DA BARR  RL REECE  D O'ROURKE  C BUTTON  JT FARAGHER 《Australian veterinary journal》1988,65(7):228-228

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Vaginal isolation of beta‐haemolytic Streptococcus from bitches with and without neonatal deaths in the litters          下载免费PDF全文

AE Guerrero  MC Stornelli  SB Jurado  G Giacoboni  GH Sguazza  RL de la Sota  MA Stornelli 《Reproduction in domestic animals》2018,53(3):609-616

The aim of the study was to identify beta‐haemolytic streptococci in the vagina of bitches who had delivered healthy litters and bitches who had delivered litters in which neonatal deaths occurred. Fifty‐one bitches divided into two groups were used. Group 1 (G1) included 28 bitches that had delivered healthy litters and group 2 (G2) included 23 bitches that had delivered puppies who died in the neonatal period. Two vaginal samples were taken, one in proestrus and the other at the end of gestation (EG). Beta‐haemolytic Streptococcus (BS) was isolated from 16 bitches (57%) in G1 and from 21 bitches (91%) in G2. The bacteriological cultures, serological tests (Streptex^®) and PCR assay allowed identification of Streptococcus canis and Streptococcus dysgalactiae in G1 and G2. Ultramicroscopic studies allowed the observation of M Protein and capsules in strains of S. dysgalactiae and S. canis in G1 and G2. The S. canis strains isolated from G2 showed thicker capsules than S. canis strains isolated from G1 (234 ± 24.2 vs 151.23 ± 28.93 nm; p < .001.). No differences were observed in capsule thickness between strains of S. dysgalactiae isolated from G1 and G2 (210 ± 13.54 vs 211.66 ± 19.67 nm; p > .70). All strains of beta‐haemolytic Streptococcus isolated were penicillin sensitive. Penicillin was administered from EG to 5 days post‐partum in 10 G2 females with isolation of BS (G2A). Saline solution was administered in eleven G2 females with isolation of BS (G2B). Ninety per cent of the puppies survived in G2A and 25% survived in G2B. Our results suggest BS is involved in canine neonatal deaths.  相似文献   

Diversity of leaf traits related to productivity in 31 Populus deltoides x Populus nigra clones     

Marron N  Villar M  Dreyer E  Delay D  Boudouresque E  Petit JM  Delmotte FM  Guehl JM  Brignolas F 《Tree physiology》2005,25(4):425-435

To test if some leaf parameters are predictors of productivity in a range of Populus deltoides (Bartr.) Marsh. x P. nigra L. clones, we assessed leaf traits and productivity in 2-month-old rooted cuttings from 31 clones growing in 4-l pots in a greenhouse, under conditions of controlled temperature and optimal irrigation. We evaluated four groups of variables describing (1) productivity (total biomass), (2) leaf growth (total leaf number increment and total leaf area increment rate), (3) leaf structure (specific leaf area and nitrogen and carbon contents) and (4) carbon isotope discrimination (delta), which is negatively correlated with time-integrated water-use efficiency. High-yielding clones did not necessarily display high leaf growth rates, but they displayed a larger total leaf area, lower specific leaf area and lower leaf nitrogen concentration than clones with low productivity. Total leaf area was mainly controlled by maximal individual leaf area and total leaf area increment rate (r = 0.51 and 0.56, respectively). Carbon isotope discrimination did not correlate with total biomass, but it was associated with total number of leaves and total leaf area increment rate (r = 0.39 and 0.45, respectively). Therefore, leaf area and specific leaf area were better indicators of productivity than leaf growth traits. The observed independence of delta from biomass production provides opportunities for selecting poplar clones combining high productivity and high water-use efficiency.  相似文献   

Managing animal wellbeing: a preliminary survey of pig farmers     

RL Wilson  PK Holyoake  GM Cronin  RE Doyle 《Australian veterinary journal》2014,92(6):206-212

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Antral Follicle Populations and Embryo Production – In Vitro and In Vivo – of Bos indicus–taurus Donors from Weaning to Yearling Ages     

KC Silva‐Santos  GMG Santos  C Koetz Júnior  F Morotti  LS Siloto  TN Marcantonio  MR Urbano  RL Oliveira  DCM Lima  MM Seneda 《Reproduction in domestic animals》2014,49(2):228-232

Interest in indicus–taurus cattle has been increasing, as these animals are likely to present the best characteristics of Zebu and European bovine breeds. The aim of this study was to compare the embryo production of indicus–taurus donors with high vs low antral follicle counts obtained by ovum pickup/in vitro production (OPU/IVP) and superovulation (SOV)/embryo collection. Braford females at weaning age (3/8 Nelore × 5/8 Hereford, n = 137, 9 ± 1 month old) were subjected to six serial ovarian ultrasonographs and were assigned to two groups according to the number of antral follicles ≥3 mm as follows: G‐High antral follicular count (AFC, n = 20, mean ≥40 follicles) and G‐Low AFC (n = 20, mean ≤10 follicles). When the females (n = 40) reached 24 months of age, they were subjected to both OPU/IVP and SOV/embryo collection. The average number of follicles remained highly stable throughout all of the ultrasound evaluations (range 0.90–0.92). The mean number of COCs recovered (36.90 ± 13.68 vs 5.80 ± 3.40) was higher (p < 0.05) for females with high AFC, resulting in higher (p < 0.05) numbers of total embryos among females with high vs low AFC (6.10 ± 4.51 vs 0.55 ± 0.83). The mean number of embryos per collection was also higher (p < 0.05) for G‐High vs G‐Low (6.95 ± 5.34 vs 1.9 ± 2.13). We conclude that a single ultrasound performed at pre‐pubertal ages to count antral follicles can be used as a predictor of embryo production following IVP and SOV/embryo collection in indicus–taurus females.  相似文献