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1.
Calves lacking detectable serum antibodies against bovine respiratory syncytial virus (BRSV) were screened for virus-specific T-cell memory. Peripheral blood mononuclear cells were cultured in vitro with live BRSV and analyzed by dual-color flow cytometry for surface expression of CD25 on CD4(+), CD8(+), and gammadeltaT-cells. Significant recall responses were detected in some of the seronegative calves. Modified live BRSV vaccine was administered to these and to a group of non-responding calves. Following vaccination, virus-specific IgG, virus neutralizing antibody, and T-cell recall responses were all elevated more rapidly in the group with BRSV-sensitive T-cells than in the T-cell-negative group, which suggested that calves in the first group were previously exposed to BRSV. This demonstrates that exposure to BRSV can induce T and B cell memory in young calves without causing seroconversion. The calves were presumably exposed to BRSV while they had maternal antibody, which inhibited the calves from developing an antibody response.  相似文献   

2.
Fifteen cattle, with the typical copper deficiency symptoms of scouring and emaciation, gained .45 pound more daily after receiving copper injections than the control group in a three-month period. Copper injections did not prevent scouring on this ranch in the North Okanagan Valley. Copper deficiency symptoms have occurred in this area whenever cattle have been restricted to forage from ground-water soils though animals improve when moved to upland soils. Dairy calves and beef cattle are most frequently affected. Subclinical deficiencies may be more important economically than the easily recognized severe deficiencies.

The average copper level in pasture forage on this ranch was 10.2 ppm and copper content of forage was not related to scouring. The average molybdenum level was 8.8 ppm but the molybdenum content of 9.7 ppm in affected forage was high compared to 2.2 ppm in forage from a pasture where scouring did not occur and 4.2 ppm in pasture which caused less scouring. The average copper to molybdenum ratio was 1.0 in the affected forage which was low compared to the ratio of 4.3 in forage from the pasture where scouring did not occur and 2.3 in forage from the pasture where there was less scouring. Manganese tended to be higher in non-scouring forage. Sulphur contents were high but not related to the degree of scouring.

In a 1957 survey on farms not far from this ranch, no difference was found between the copper and molybdenum contents of scouring and non-scouring forage though copper was double and molybdenum comparable to levels found on this ranch. However, in the survey, scouring forage contained .65 per cent sulphur whereas non-scouring forage only contained .26 per cent.

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3.
AIMS: The aims of this study were (a) to evaluate the effect of xylazine and tolazoline, with and without lignocaine, on the cortisol response of calves following amputation dehorning and (b) to assess the effect of a non-steroidal anti-inflammatory drug (ketoprofen) and local anaesthesia on the cortisol response of calves to amputation dehorning. METHODS: Plasma cortisol concentrations were measured in 100 dehorned or non-dehorned 3-month-old calves over an 8-h period following five different sedative/analgesic or control treatments. Sedative/analgesic treatments were: control (no anaesthesia); local anaesthesia and ketoprofen; local anaesthesia and xylazine; local anaesthesia, xylazine and tolazoline; and xylazine only. Within each sedative/analgesic treatment group, half the calves (n=10 per group) were amputation dehorned and half were not dehorned. RESULTS: The change in plasma cortisol concentrations in calves dehorned after being given ketoprofen and local anaesthesia did not differ significantly from that of non-dehorned control calves for at least 8 h. In contrast, the cortisol response of dehorned calves not given analgesic drugs peaked 30 min after dehorning and lasted >4 h. Xylazine injected before dehorning significantly reduced but did not eliminate the peak of the cortisol response. When both xylazine and local anaesthesia were administered before dehorning the peak in the cortisol response was virtually eliminated. In the dehorned calves that received xylazine with or without local anaesthesia, cortisol concentration increased significantly 3 h after dehorning and did not return to baseline until at least 5 h later. When tolazoline was administered shortly after xylazine, it caused a marked cortisol response, higher than the response to any other treatment. CONCLUSIONS: Combining ketoprofen and local anaesthesia minimised the cortisol response, and by inference the pain-induced distress, following amputation dehorning in calves. Xylazine reduced the initial cortisol response to dehorning but not as much as when local anaesthesia was also given. The increase in cortisol concentration from 3-8 h after dehorning in calves given xylazine alone or in combination with local anaesthesia suggests that calves experienced pain-induced distress during this time and that xylazine had no long-term analgesic effect. Tolazoline, used to reverse the sedative effects of xylazine, caused a marked cortisol response in calves via a mechanism which remains unclear.  相似文献   

4.
An experiment was conducted to determine the effects of yeast culture (YC) and modified yeast culture [YC + cell wall product (CWP) containing mannan oligosaccharides] in pig diets on the performance, gut integrity, and blood cell composition of weanling pigs and to determine whether these dietary supplements could replace antimicrobial growth promoters (AGP) in pig diets. A total of 480 weanling pigs (27 d old and 7.8 +/- 0.1 kg of BW) were assigned to 1 of 4 experimental treatments: 1) diets without AGP or YC (control diet); 2) control + AGP; 3) control + 0.125% YC; and 4) control + 0.125% YC + 0.2% CWP. Piglets were fed experimental diets for 5 wk after weaning. Blood samples were collected from 8 piglets at weaning and from 8 piglets per treatment on d 14 and 35 after weaning for blood cell composition. These piglets were slaughtered for measurement of villous length and crypt depth in the jejunal mucosa and microbial profiling on the intestinal digesta. Average daily gain (P = 0.06) and G:F (P = 0.02) were improved for piglets that were fed the supplemented diets compared with piglets that were fed the control diet. Average daily feed intake was unaffected by dietary treatment. Performance was similar in piglets fed diets supplemented with AGP, YC, and YC + CWP. Blood cell composition, villous length, crypt depth, and microbial composition in the gut were unaffected by dietary treatment, but they were affected by time after weaning. Red blood cells, hemoglobin, hematocrit value, mean cell volume, mean cell hemoglobin, percentage of lymphocytes in the leukocyte population, villous length, and crypt depth were greater (P < 0.05) at 5 wk after weaning than at 2 wk after weaning. Eosinophils (P = 0.06) in the leukocyte population tended to be greater at 5 wk after weaning. Concentration of neutrophils in the leukocyte population and percentages of CD4 and CD8 cells were lower (P < 0.02) at 5 wk after weaning. The CD4:CD8 ratio (P = 0.07) tended to be lower at 5 wk after weaning. Results suggest that yeast culture could be an alternative to AGP in the diets of weanling pigs and that addition of CWP to diets containing YC would not improve the performance or health of weanling pigs above that of YC alone. Thus, more insight into the mode of action of YC is needed.  相似文献   

5.
We compared the ability of two oral electrolyte solutions to resuscitate calves with experimentally induced diarrhoea and dehydration. Sucrose solution, furosemide, spironolactone, and hydrochlorothiazide were administered to 18 male Holstein-Friesian calves to induce diarrhoea and dehydration. Clinical changes after 24 h included severe diarrhoea, moderate dehydration (8-10% body weight), azotemia, and clinical depression. Calves were then randomly assigned to one of three treatment groups (milk replacer, 2 L every 12 h; hyperosmotic oral electrolyte solution, 2 L every 12 h; iso-osmotic oral electrolyte solution, 1.5 L every 6 to 12 h) and followed for an additional 48 h.Compared to feeding milk replacer, the hyperosmotic solution significantly (P< 0.05) improved hydration status, increased body weight, maintained urine production, decreased the degree of clinical depression and prevented development of metabolic acidosis, although serum glucose concentration was decreased at 24 h and 48 h. The hyperosmotic solution produced a similar resuscitative response to the iso-osmotic solution, but maintained higher serum glucose concentrations and lower serum beta-OH butyrate and non-esterified fatty-acid concentrations, indicating that the hyperosmotic solution provided greater nutritional support. The hyperosmotic solution rehydrated calves faster and more effectively than feeding equivalent volumes of milk replacer and can, therefore, be recommended as part of the initial treatment of dehydrated calves with diarrhoea.  相似文献   

6.
Various vaccines containing the 919 strain of ephemeral fever virus were evaluated in experimental calves and in commercial cattle. The vaccine virus was mixed with one of the adjuvants, Quil A (a saponin derivative), aluminium hydroxide gel, dextran sulphate or combinations of these. The response of experimental calves was evaluated by measuring the production of neutralising antibodies and by resistance to challenge with virulent virus; the response of commercial cattle was judged only by the production of neutralising antibody. Twelve calves given two doses of vaccine containing Quil A produced neutralising antibodies to bovine ephemeral fever virus and all were resistant to challenge with virulent virus given 28 to 76 days after the second vaccination. The vaccine given in three of these calves also contained aluminium hydroxide gel. Six of eight unvaccinated control calves succumbed to experimental challenge. In commercial cattle (17 to 26 animals per group) the serological response after two doses of vaccine containing Quil A or Quil A and dextran sulphate was significantly better than that after vaccines containing only dextran sulphate or after vaccines containing combinations of aluminium hydroxide gel and Quil A. The adjuvant Quil A alone was tested in cattle and shown to produce a transient soft swelling at the injection site as well as a rise in rectal temperature of greater than 1 degree C one day after inoculation. At least 99.99 per cent of viral infectivity was destroyed when the vaccine was mixed with Quil A, suggesting that live virus may not be essential in the immunogenicity of the vaccine. This vaccine overcame two of the problems associated with previous attenuated vaccines tested in Australia; the necessity for adjuvant and virus to be mixed immediately before use and the large volume of the vaccine.  相似文献   

7.
本试验旨在研究益生菌对犊牛生长性能和血清生化指标的影响.选取24头新生荷斯坦犊牛,随机分为4组,每组公母各1/2,分别饲喂基础饲粮(A组,由代乳粉、开食料和羊草组成)、基础饲粮+地衣芽孢杆菌(B组)、基础饲粮+地衣芽孢杆菌与枯草芽孢杆菌的复合菌(C组,复合菌中各菌菌数比例为1∶1)、基础饲粮+地衣芽孢杆菌、枯草芽孢杆菌和植物乳酸杆菌的复合菌(D组,复合菌中各菌菌数比例为1∶1∶1).每头牛食入益生菌总数为2×1010 CFU/d.试验期共8周,分0～2周龄、2～4周龄、4～6周龄和6～8周龄4期.每2周空腹称重、测量体尺、采血1次,每天记录采食量和粪便评分情况.试验0～8周龄,B组的平均日增重显著高于A组(P＜0.05),试验各组的料重比差异不显著(P＞0.05);第8周龄时,B组和D组的体躯指数均显著高于A组(P＜0.05);试验各组采食量和犊牛粪便评分差异不显著(P＞0.05);血清生化指标不受本试验处理因素影响(P＞0.05).结果表明,饲粮中添加地衣芽孢杆菌单菌提高了犊牛0～8周龄的平均日增重和8周龄的体躯指数,添加地衣芽孢杆菌与枯草芽孢杆菌和植物乳酸杆菌的复合菌提高了犊牛8周龄的体躯指数,添加益生菌对犊牛血清生化指标没有显著影响.  相似文献   

8.
AIMS: The aims of this study were (a) to evaluate the effect of xylazine and tolazoline, with and without lignocaine, on the cortisol response of calves following amputation dehorning and (b) to assess the effect of a non-steroidal anti-inflammatory drug (ketoprofen) and local anaesthesia on the cortisol response of calves to amputation dehorning.

METHODS: Plasma cortisol concentrations were measured in 100 dehorned or non-dehorned 3-month-old calves over an 8-h period following five different sedative/analgesic or control treatments. Sedative/analgesic treatments were: control (no anaesthesia); local anaesthesia and ketoprofen; local anaesthesia and xylazine; local anaesthesia, xylazine and tolazoline; and xylazine only. Within each sedative/analgesic treatment group, half the calves (n=10 per group) were amputation dehorned and half were not dehorned.

RESULTS: The change in plasma cortisol concentrations in calves dehorned after being given ketoprofen and local anaesthesia did not differ significantly from that of non-dehorned control calves for at least 8 h. In contrast, the cortisol response of dehorned calves not given analgesic drugs peaked 30 min after dehorning and lasted >4 h. Xylazine injected before dehorning significantly reduced but did not eliminate the peak of the cortisol response. When both xylazine and local anaesthesia were administered before dehorning the peak in the cortisol response was virtually eliminated. In the dehorned calves that received xylazine with or without local anaesthesia, cortisol concentration increased significantly 3 h after dehorning and did not return to baseline until at least 5 h later. When tolazoline was administered shortly after xylazine, it caused a marked cortisol response, higher than the response to any other treatment.

CONCLUSIONS: Combining ketoprofen and local anaesthesia minimised the cortisol response, and by inference the pain- induced distress, following amputation dehorning in calves. Xylazine reduced the initial cortisol response to dehorning but not as much as when local anaesthesia was also given. The increase in cortisol concentration from 3–8 h after dehorning in calves given xylazine alone or in combination with local anaesthesia suggests that calves experienced pain-induced distress during this time and that xylazine had no long-term analgesic effect. Tolazoline, used to reverse the sedative effects of xylazine, caused a marked cortisol response in calves via a mechanism which remains unclear.  相似文献   

9.
Three doses of an alpha 2-adrenoreceptor antagonist, atipamezole, were administered to reverse xylazine-induced sedation, bradycardia, and ruminal atony in calves. Once a week for 4 weeks, each of 6 calves was administered IV 1 treatment of: 0.3 mg of xylazine/kg of body weight, followed in 10 minutes by 1 ml of 0.9% NaCl; 0.3 mg of xylazine/kg, followed in 10 minutes by 3 micrograms of atipamezole/kg; 0.3 mg of xylazine/kg, followed in 10 minutes by 10 micrograms of atipamezole/kg; or 0.3 mg of xylazine/kg, followed in 10 minutes by 30 micrograms of atipamezole/kg. The order of the 4 treatments in each calf was selected at random. Xylazine alone caused lateral recumbency for 33.6 +/- 7.1 minutes (mean +/- SEM). Atipamezole administered at dosages of 3, 10, and 30 micrograms/kg shortened xylazine-induced lateral recumbency to 20.5 +/- 3.0, 10.2 +/- 0.2, and 9.3 +/- 0.5 minutes, respectively. Calves given xylazine alone stood at greater than 60 minutes after the onset of recumbency. Atipamezole given at 3, 10, and 30 micrograms/kg shortened the time from onset of lateral recumbency to standing to 40.2 +/- 6.9, 12.8 +/- 1.1, and 10.0 +/- 0.7 minutes, respectively. Drowsiness was found in calves given the lowest dosage of atipamezole (3 micrograms/kg) after the calves stood. Atipamezole given at dosages of 10 and 30 micrograms/kg reversed xylazine-induced ruminal atony in a dose-dependent manner. In addition, 30 micrograms of atipamezole/kg reversed xylazine-induced bradycardia, but the lower dosages of this antagonist did not. Results indicated that 30 micrograms of atipamezole/kg should be a useful antidote for xylazine overdose in cattle.  相似文献   

10.
Two doses of an alpha 2-adrenoreceptor antagonist, idazoxan, were administered to reverse the CNS depressant and bradycardia effects of xylazine in calves. Once a week for 3 weeks, each of 6 calves were administered IV one treatment of: (1) 0.2 mg of xylazine/kg of body weight followed in 10 minutes by 1 ml of 0.9% NaCl, (2) 0.2 mg of xylazine/kg followed in 10 minutes by 10 micrograms of idazoxan/kg, or (3) 0.2 mg of xylazine/kg followed in 10 minutes by 30 micrograms of idazoxan/kg. The order of the 3 treatments in each calf was selected at random. Xylazine alone caused lateral recumbency for 27.2 +/- 3.0 minutes (mean +/- SEM). Idazoxan administered at dosages of 10 and 30 micrograms/kg shortened xylazine-induced lateral recumbency to 11.5 +/- 0.8 and 10.3 +/- 0.2 minutes, respectively. Calves given xylazine alone stood at greater than 60 minutes after the onset of recumbency. Idazoxan given at dosages of 10 and 30 micrograms/kg shortened the time to standing to 16.8 +/- 1.7 and 11.3 +/- 0.2 minutes, respectively. Idazoxan given at a dosage of 30 micrograms/kg also reversed xylazine-induced bradycardia. Results indicated that idazoxan should be a useful antidote for xylazine overdose in cattle.  相似文献   

11.
The efficacy of danofloxacin 18% against naturally occurring Escherichia coli diarrhoea was investigated in calves at seven European sites. Treatment commenced on day 0, with either a single subcutaneous injection of danofloxacin 18% (n=267) at 6 mg/kg repeated on day 2 if required, or reference product containing baquiloprim/sulphadimidine (n=37) or gentamicin (n=98) administered as recommended. E. coli was isolated from 90% to 100% of calves pre-treatment, and the prevalence of serotypes K99 and F41 was 8-46% and 46-92%, respectively. In both treatments, the majority of calves (93.2-93.9%) showed clinical improvement and completed the studies. There were significant reductions for both treatments, in severity of clinical signs on days 4 and 10 compared to day 0 (P<0.0001), and between days 4 and 10 (P<0.05), but no significant differences between treatments (P>0.05). Danofloxacin 18% was clinically safe, and as effective as the reference products in the treatment of E. coli diarrhoea in calves.  相似文献   

12.
Studies were conducted on the enumeration of 7 groups of fecal microflora including total aerobes, total anaerobes, coliforms, lactobacilli, staphylococci, streptococci and yeasts and molds of 18-day old piglets. These pigs were early weaned (21 days) on different modifications of an early-weaning ration. The above mentioned microflora were enumerated again when some of the pigs in a replicate started scouring. The occurrence of diarrhea was always associated with significant increases in the numbers of coliforms and corresponding decreases in the lactobacilli counts. No other single group of fecal microflora differed in the scouring and non-scouring animals. The composition of the early-weaning ration offered to the animals did not, in itself, influence the fecal microflora to any appreciable extent.

In another series of experiments, enumeration of coliforms and lactobacilli was conducted on samples obtained from different segments of the intestinal tracts of scouring and non-scouring pigs. Increased numbers of coliforms and decreased numbers of lactobacilli were observed at all levels of the intestinal tracts of the scouring animals. However, these changes were more marked in the duodenal samples than in those obtained from other parts of the intestine.

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13.
Beef cattle health and performance records of 3637 calves from inbred and outbred populations were evaluated to determine the effect of scours on weaning BW (WW). Animals were maintained under similar environmental conditions at the Northern Agricultural Research Center near Havre, Montana. Inbred animals were linebred Hereford cattle with an average inbreeding coefficient of 0.20. Outbred animals were Hereford, Angus × Hereford, Simmental × Hereford crosses and backcrosses, and Tarentaise × Hereford crosses and backcrosses. Weaning BW was analyzed by least squares ANOVA. Model included year, age of dam, line (inbred or outbred), scours, and date of birth as a covariate. When zero WW were included for calves that died of scours (1%), all main effects were important. The least squares mean WW were 208 and 217 kg for scouring and non-scouring groups, respectively. Interactions between year × age of dam (P < 0.01) and year × line (P < 0.01) were detected. Incidence of scours was analyzed by the CATMOD procedure of SAS. The model included year, age of dam, and line (inbred or outbred). All main effects were important (P < 0.01). Incidence of scours ranged from 13% in 1982 to 64% in 1991. Incidence of scours was greatest in calves born to 2-yr-old dams with probabilities of 47% and 33% in inbred and outbred dams, respectively. These results indicate that scours negatively influenced WW. Incidence of scours was greater in calves born to younger dams and for inbred cattle.  相似文献   

14.
An esophageal feeder and a rubber nasoesophageal tube were used to administer fluids to calves. Radio-opaque fluids were given and their destination determined by fluoroscopy and radiography. Fluids containing glucose and xylose were also given and plasma glucose and xylose concentrations measured. In at least 93% of calves, the radio-opaque fluids entered the reticulum, indicating that the reticular groove did not close. Oral administration of sodium bicarbonate, copper sulfate and guanidine HCl did not influence groove closure in calves that received fluids through an esophageal feeder. As administration of the fluids continued, overflow to the abomasum occurred after about 400 mL had been given. When 2.0 L of glucose and electrolyte solution was given by esophageal feeder, plasma glucose levels rose significantly (p less than 0.01), showing that absorption had occurred. Plasma xylose levels rose in seven out of eight calves 30 minutes after a second 2.0 L dose (containing xylose) had been administered. Thus, even though esophageal feeders do not cause reticular groove closure, they can be used to administer fluids for enteric absorption, provided large quantities are given.  相似文献   

15.
The feeding of ethylenediamine dihydriodide (EDDI) at the dose levels of 50 and 500 mg/animal/day and urea at the dose level of 45 g/animal/day did not affect duration of clinical signs, body weight gain, magnitude or duration of fever, serum concentration of glutamic oxalacetic transaminase, packed cell volume, and differential white blood cell counts in feeder cattle experimentally infected with infectious bovine rhinotracheitis (IBR) virus. However, coughing and abundance of nasal discharge were significantly greater in calves fed EDDI before and during primary IBR virus infection. Those calves fed 500 mg of EDDI/day coughed more, had greater nasal discharge, and exhibited greater lacrimation than did those given the smaller dose. These 3 clinical signs were considered to reflect both the expectorant action of EDDI and the pathogenic effects of IBR virus. In all calves, including controls, the coughing, nasal discharge, and lacrimation were most prominent during the period of peak infection (7 to 14 days after the calves were given intranasal inoculation) of the IBR virus. Total serum iodine concentration became maximal (mean of 1,400 ng/ml) in 8 calves after they had been fed the larger dose of EDDI for 2 weeks. This value was maximal (about 300 ng/ml) in another 8 calves after 3 weeks' feeding of the smaller dose (50 mg/day). When EDDI exposure was maintained at the dose level of 50 mg/day for 5 weeks longer, mean serum iodine values remained at about 275 ng/ml, and those of control calves averaged 140 ng/ml.  相似文献   

16.
Thirty-six dehydrated diarrheic neonatal calves were used to study the effects of various alkalinizing compounds on acid-base status, the changes in central venous pressure (CVP) in response to rapid IV infusion of large volumes of fluid, and the correlation of acid-base (base deficit) status, using a depression scoring system with physical determinants related to cardiovascular and neurologic function. Calves were allotted randomly to 4 groups (9 calves/group). Over a 4-hour period, each calf was given two 3.6-L volumes (the first 3.6 L given in the first hour) of a polyionic fluid alone (control group) or were given the polyionic fluid with sodium bicarbonate, sodium L-lactate, or sodium acetate added (50 mmol/L). Acid-base status, hematologic examination, and biochemical evaluations were made immediately before infusion of each fluid (at entry) and after 3.6, 4.8, and 7.2 L of fluid had been given. Compared with control values, bicarbonate, lactate, and acetate had significantly greater alkalinizing effects on pH (P less than 0.01) and base deficit (P less than 0.01) after 3.6, 4.8, and 7.2 L of fluid were given. Bicarbonate had the most rapid alkalinizing effect and induced greater changes in base deficit (P less than 0.01) than did acetate or lactate at each of the 3 administered fluid volumes evaluated. Acetate and lactate had similar alkalinizing effects on blood. Rehydration alone did not improve acid-base status. The CVP was elevated in 10 (28%) of the 36 calves after 1 hour of fluid (3.6 L) administration, but significant differences in body weight, PCV, and clinical condition or depression score at entry were not found between calves with elevated CVP and those with normal CVP.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

17.
Dairy calves under 14 days of age with naturally occurring, uncomplicated diarrhea were treated for 3 days with a hypertonic oral electrolyte solution with (n = 15) or without (n = 12) psyllium. Clinical response and clinical pathology data were compared between the 2 groups. Glucose absorption was evaluated on days 1 and 3 by measurement of plasma glucose and lactate and serum insulin concentrations for 4 hours after formula administration. On day 1, glucose, lactate, and insulin concentrations were lower in psyllium-fed calves than in control calves, with significant differences noted in glucose and lactate concentrations at several time points ( P < 0.05). Plasma lactate concentrations were higher at several times in both treatment groups on day 3 than on day 1 ( P < 0.05). Fecal consistency was markedly different in psyllium-fed calves as compared with control calves within 24 hours of psyllium supplementation. Fecal percent dry matter content was lower in psyllium-fed calves than in control calves at least once a day during supplementation and on day 3 compared with day 0 in the psyllium-fed calves ( P < 0.05). There were no significant differences in clinical performance scores, hydration status, arterial blood gas, serum anion gap, electrolyte, or total CO, concentrations. Addition of psyllium to an oral electrolyte solution resulted in immediate alterations in glucose absorption without impairing rehydration in diarrheic calves, but differences were transient and did not affect clinical outcome.  相似文献   

18.
Cellular activation and functional cell surface markers were evaluated during experimentally-induced endotoxemia in healthy horses. Eight healthy adult horses were infused a low dose of endotoxin (lipopolysaccharide from Escherichia coli O26: B6, 30 ng/kg of body weight, IV) and five control horses were given an equivalent volume of sterile saline solution. Venous blood samples were collected for flow cytometric analysis of peripheral blood mononuclear cells (PBMCs) and to measure plasma endotoxin concentrations. Clinical signs of endotoxemia were recorded at 10, 20, 30, 40, 50 min, 1, 2, 3, 4, 8, 16, 24 and 48 hr after endotoxin or saline solution administration. Clinical findings characteristic of endotoxemia (tachycardia, tachypnea, increased rectal temperature, and leukopenia) occurred transiently in all horses administered endotoxin; however, plasma endotoxin concentrations were detectable in only 50% (4/8) of the endotoxin-infused horses. The percentage of CD4(+), CD5(+), and CD8(+) cells decreased while the percentage of CD14(+), IgM(+), and MHC class II(+) cells increased significantly after endotoxin infusion. Alterations in the immunophenotype of PBMCs from horses with experimentally-induced endotoxemia were associated with changes in vital signs, indicating that endotoxin altered the immuno balance.  相似文献   

19.
The pathogenicity of Haemoplasma spp. in cats varies with 'Candidatus Mycoplasma haemominutum' (CMhm) causing subclinical infection while Mycoplasma haemofelis (Mhf) often induces haemolytic anaemia. The aims of this study were to characterise the acute phase response (APR) of the cat to experimental infection with Mhf or CMhm, and to determine whether chronic feline immunodeficiency virus (FIV) infection influences this response. The acute phase proteins serum amyloid A (SAA), haptoglobin (Hp) and α-1-acid glycoprotein (AGP) concentrations were measured pre-infection and every 7-14days up to day 100 post-infection (pi) in cats infected with either Mhf or CMhm. Half of each group of cats (6/12) were chronically and subclinically infected with FIV. Marbofloxacin treatment was given on days 16-44 pi to half of the Mhf-infected cats, and on days 49-77 pi to half of the CMhm-infected cats. FIV-infected animals had significantly lower AGP concentrations, and significantly greater Hp concentrations than non-FIV-infected cats when infected with CMhm and Mhf, respectively. Both CMhm and Mhf infection were associated with significant increases in SAA concentrations, while AGP concentrations were only significantly increased by Mhf infection. Mhf-infected cats had significantly greater SAA concentrations than CMhm-infected animals. Both Mhf and CMhm infections were associated with an APR, with Mhf infection inducing a greater response. Chronic FIV infection appeared to modify the APR, which varied with the infecting Haemoplasma species.  相似文献   

20.
Lungworm-infected seeder calves were used on four 1.41 ha paddocks to ensure that groups of 11 calves would be exposed to a heavy challenge with Dictyocaulus viviparus. By the 39th day after turnout there was a serious episode of respiratory disease and a diagnosis of parasitic bronchitis was confirmed by post mortem and faecal examination. One group of trial calves was treated with netobimin administered in the drinking water at 2.8 mg/kg/day for seven consecutive days; another group received the same treatment supplemented with flunixin meglumine at 2.2 mg/kg/day for three days; a third group was given a single oral dose of 7.5 mg netobimin/kg; only emergency treatments were given to calves in the control group. The clinical response to the drinking water treatments was highly satisfactory and better than the response to the single oral treatment.  相似文献   

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