Tracheal mucus transport rate in normal turkeys and in turkeys infected with Bordetella avium (Alcaligenes faecalis)     

M D Ficken  J F Edwards  J C Lay  D E Tveter 《Avian diseases》1986,30(1):154-159

Using the radiopharmaceutical 99mtechnetium-sulfur colloid, the tracheal mucus transport rate (TMTR) was measured in healthy unanesthetized turkeys and in turkeys infected with Bordetella avium. The TMTR of uninfected turkeys was 35.6 +/- 14.4 cm/min. The TMTR of B. avium-infected turkeys was normal on days 0 through 14 postexposure (PE), despite heavy bacterial colonization of the tracheal epithelium. On day 21 PE, the TMTR of B. avium-infected turkeys was significantly depressed (P less than or equal to 0.01) compared with that of control turkeys. Depressed transport was associated with extensive loss of ciliated epithelium from the tracheal mucosa and replacement of the normal mucosa by immature nonciliated epithelium or metaplastic squamous epithelium.  相似文献   

广西筛选稻瘟病抗源品种的初步研究     

赖星华 《植物病理学报》1981,11(2):1-5

 1973~1979年间,在广西稻瘟病圃试验了11198个水稻品种。有一些抗病品种曾以人工接种测定.其中23个品种呈现稳定的高抗至中抗反应。
试验结果表明,红脚占、砦糖、金围矮是广谱抗稻瘟病的品种。
初步观测表明,叶瘟与穗瘟的抗病反应是相关的。
文中讨论了对稻瘟病抗病性的类型,未发现范德普兰克(1968年)描述的对病原的所有小种反应一致的水平抗性品种。  相似文献   

Sequential bacteriological observations in relation to cell-mediated and humoral antibody responses of cattle infected with Mycobacterium paratuberculosis and maintained on normal or high iron intake   总被引：3，自引：0，他引：3  

AWD LEPPER  CR WILKS†  M. KOTIW†  JT WHITEHEAD†  KS SWART† 《Australian veterinary journal》1989,66(2):50-55

Twenty calves were orally infected with Mycobacterium paratuberculosis before weaning. Ten of these plus 4 non-infected controls were maintained on elevated dietary iron intake from 6 to 33 months of age. During this time, in which the majority of animals were bred, the influence of increased dietary iron upon tests of cellular and humoral immune responsiveness to antigens of the organism were monitored. Results were examined in relation to the organism's capacity to multiply and infect up to 7 portions of the intestinal tract. No significant differences were detected in the degree of intestinal disease or pattern of faecal excretion of M. paratuberculosis in iron supplemented and non-supplemented cattle. Cutaneous delayed-type hypersensitivity (DTH) to johnin PPD developed at 1 month and in-vitro lymphocyte and immunostimulatory activity (LS) to this antigen at 2 months after infection. LS indices were significantly reduced in magnitude in iron-supplemented cattle (p less than 0.01). Most ELISA antibody responses were positive 10 to 17 months after infection and preceded the fewer number of CF responses by several months. Neither of the antibody tests was affected by elevated iron intake. Generally, complete or partial resistance to paratuberculosis was associated with sustained positive monthly LS tests (index greater than or equal to 2.0), whereas antibody levels tended to be sustained only in the more severely affected cattle. Although neither test system was affected by pregnancy the ELISA failed to detect a significant proportion of cattle chronically shedding M. paratuberculosis in faeces.  相似文献   

Resistance to synthetic pyrethroids in South Australian populations of sheep lice (Bovicola ovis)     

PJ JAMES  PE SAUNDERS  KS COCKRUM  KJ MUNRO 《Australian veterinary journal》1993,70(3):105-108

SUMMARY Lice were collected from 71 flocks detected as Infested at market Inspection in 1990 and 1991, from 16 flocks where resistance was suspected and from 31 flocks from Kangaroo Island. Susceptibility to cypermethrin was measured by a treated surface technique and survival of lice at 5 ppm or greater was taken as an indication of resistance. The prevalence of resistance was 34% in louse populations from the market inspection sample, 50% in flocks in which resistance was suspected and 68% in flocks from Kangaroo Island. Most resistance factors were in the range 1 to 20 although one louse population with a resistance factor of 91 was found on Kangaroo Island.  相似文献   

Development of the chicken as a model for prenatal stress     

Lay DC  Wilson ME 《Journal of animal science》2002,80(7):1954-1961

Exposing a pregnant mammal to stressors causes behavioral and physiological alterations in her offspring ("prenatal stress"); however, elucidation of the underlying mechanism is hindered by an inability to control maternal compounds that may affect the fetus. We designed this experiment to determine if the autonomously developing chicken embryo could be developed as a model for prenatal stress. On d 16 of incubation, eggs were treated with: 1) 60 ng corticosterone (CORT), 2) elevated incubation temperature (40.6 degrees C) for 24 h (HEAT), or 3) no treatment (Control). Chicks from all three treatments hatched at similar weights; however, HEAT chicks weighed less by 100 d of age and remained lighter until the end of the study (P < 0.05). At 8 d post-beak trimming, adrenal gland weight was not different (P > 0.20) among treatments, basal plasma corticosterone concentrations tended (P < 0.06) to be greater for CORT chicks than either the Control or HEAT chicks, and CORT chicks were heavier than HEAT chicks (P < 0.005) but not Control chicks (P > 0.20). At 11-wk, HEAT birds had heavier adrenal glands than did Control birds (P < 0.01). At 16 wk of age, Control cocks performed more (P < 0.01) pecking aggression than either HEAT or CORT cocks, whereas CORT cocks were chased more often and chased another cock less often than either HEAT or Control cocks (P < 0.01). Treatments did not alter the behavior of the hens (P > 0.10). Administration of corticosterone during incubation replicated some, but not all, of the effects seen in prenatal stress in mammals.  相似文献   

Administration of ACTH to restrained, pregnant sows alters their pigs' hypothalamic-pituitary-adrenal (HPA) axis     

Haussmann MF  Carroll JA  Weesner GD  Daniels MJ  Matteri RL  Lay DC 《Journal of animal science》2000,78(9):2399-2411

This study was designed to examine the physiology and behavior of pigs whose dams were snared and then injected with ACTH during gestation. Administration of ACTH to dams during pregnancy has been shown to replicate the effects of prenatal stress in other species. Control sows (n = 8) were given no treatment, whereas the treatment sows (ACTH, n = 8) were immobilized by snaring the snout and then administered an i.v. injection of ACTH (1 IU/kg BW) weekly from 6 to 12 wk of gestation. A pig was killed from each sow at 1, 30, and 60 d of age. The hypothalamus, pituitary gland, adrenal glands, and liver were immediately obtained to determine the amounts of corticotropin-releasing hormone (CRH), beta-endorphin, and mRNA for pro-opiomelanocorticotropin (POMC), the ACTH receptor (ACTH-R), and insulin-like growth factor I (IGF-I). Pituitary corticotrope and somatotrope cell numbers and adrenal cortex-to-medulla area ratios (CORT:MED) were also determined. Pigs' behaviors were recorded at 6 and 8 wk of age. At 75 d of age, a blood sample was taken and a biopsy puncture was created on one pig from each litter, then pigs were stressed by mixing. Blood was sampled every other day for 10 d to determine plasma cortisol concentrations and differential leukocyte counts. Biopsy damage was evaluated for healing. At 1 d of age, control pigs tended to weigh more (P = .09), have a lower expression of ACTH-R mRNA (P = .01) and IGF-I mRNA (P = .01), and a lower CORT:MED (P = .04) than ACTH pigs. At 30 d of age, control pigs had a greater concentration of beta-endorphin (P = .01) and tended to have a lower concentration of CRH (P = .09) and IGF-I mRNA (P = .10) than ACTH pigs. At 60 d of age, control pigs tended to have lighter pituitary glands (P = .08), a lower expression of POMC mRNA (P = .02), and a CORT:MED (P = .003) than ACTH pigs. At 8 wk of age, control pigs performed a higher frequency of belly nosing (P = .07) and oral vice behaviors (P = .01) than ACTH pigs. In response to mixing stress, control pigs had lesser concentrations of plasma cortisol (P = .03) and healed faster (P = .006) than ACTH pigs. Thus, exogenous ACTH and restraint during gestation alters the HPA axis of the sow's offspring, and during stressful situations later in life health, and therefore welfare, may be compromised.  相似文献   

Danger to pigs due to crushing can be reduced by the use of a simulated udder.     

D C Lay  M F Haussmann  H S Buchanan  M J Daniels 《Journal of animal science》1999,77(8):2060-2064

Sows that lie on their young, pig "crushing", is a significant cause of pig mortality in current production systems. Although mortality rates of pigs in farrowing crates are lower than mortality rates of pigs in pens, loss due to crushing is still estimated to be between 4.8 and 18%. During the first few days after parturition, pigs are highly attracted to the odor of their dam's udder. Thus, our research was designed to move the pigs away from the sow by competing with the sow's udder using a "simulated" udder. Fifteen Yorkshire x Landrace sows and their litters (11.4+/-.78 pigs) were assigned to either a control (C, n = 9) or an experimental group (SU, n = 6). The C pigs had access to a heat lamp, whereas the SU pigs' crate had a simulated udder. Data were collected using time-lapse photography (1 frame/.4 s) for a 3-d duration at the initiation of farrowing. When a sow stood, data were recorded by 1-min scan samples to record the number of pigs using either the heat lamp or the simulated udder. In addition, stillborn pigs, pig crushing, and death by other means also were recorded. Data were analyzed by 12-h periods using generalized estimating equations. Results indicate that from 12 to 72 h postpartum, excluding 24 to 36 h postpartum, the estimated probability that pigs were in a safe area (simulated udder or heat lamp) was .89 for SU pigs, compared with only .72 for C pigs (P = .005). During the 24- to 36-h period, it was more probable to find pigs on a simulated udder (.77) than under only a heat lamp (.61, P = .016). Stillborn pigs, pig crushing, and death by other means were not different between treatments (mean = .87, .60, 1.2; P>.20). The simulated udder drew pigs away from the sow's udder better than heat lamps alone. Considering these findings, mortality of pigs due to crushing may be decreased substantially using a simulated udder. These results are promising, but further refinement should be done, including improved udder design and investigation of the attractiveness of various stimuli.  相似文献   

Freshwater turtle admissions to a wildlife hospital in South-East Queensland,Australia over an eleven-year period, 2010–2021     

KS O'Leary  A Hill  RJT Doneley 《Australian veterinary journal》2023,101(6):258-264

  相似文献   

Assessing the adaptation of swine to fifty-seven hours of feed deprivation in terms of behavioral and physiological responses     

Toscano MJ  Lay DC  Craig BA  Pajor EA 《Journal of animal science》2007,85(2):441-451

Dramatic changes in the livestock industry have brought about widespread concern regarding the welfare of animals in terms of the hunger that they may experience. Despite this concern, animal science has not been able to provide a methodology that can objectively determine whether the welfare of animals is compromised by hunger. The current work sought to provide data that characterized the physiological and behavioral responses of animals experiencing 57 h of food deprivation. For this purpose, 2 separate experiments were conducted, in which physiological or behavioral measures were collected from swine deprived of feed for 21 to 57 h or fed normally (physiology, n = 20/treatment; behavior, n = 8/treatment). Treatment x time interactions were found (P < 0.02) for insulin, beta-hydroxybutyrate, NEFA, drinking, standing, inactivity, lying sternal, lying lateral, and total lying. Animals appeared to adjust appropriately to the metabolic challenge imposed, as suggested by increases in alternative energy substrates (NEFA, beta-hydroxybutyrate). Additionally, feed-deprived animals appeared less active than control animals until after 45 h of feed deprivation, when the former appeared to be more active. Our results suggest that feed deprivation of finishing pigs for durations greater than 45 h produced behavioral changes that may be related to increased sensations of hunger and which possibly are dependent on the use of alternative energetic substrates. Our data link behavioral and physiological changes after the imposition of feed deprivation.  相似文献   

Variation of interplate fault zone properties with depth in the japan subduction zone   总被引：2，自引：0，他引：2  

SL Bilek  T Lay 《Science (New York, N.Y.)》1998,281(5380):1175-1178

The depth dependence of physical properties along the Japan subduction zone interface was explored using teleseismic recordings of earthquake signals. Broadband body waves were inverted to determine the duration of rupture and source depth for 40 interplate thrust earthquakes located offshore of Honshu between 1989 and 1995. After scaling for differences in seismic moment, there is a systematic decrease in rupture duration with increasing depth along the subducting plate interface. This indicates increases in rupture velocity or stress drop with depth, likely related to variation in rigidity of sediments on the megathrust.  相似文献