共查询到20条相似文献，搜索用时 31 毫秒
1.
This study was initiated to determine the etiologic and pathogenic significance of an American strain of bovine viral diarrhea (BVD) virus (strain NADL-MD) in enteritis of neonatal calves (calf scours). Three colostrum-fed calves from dams exposed intravenously to BVD virus at 6, 16 and 25 days prepartum, respectively, had moderate diarrhea persisting until the eighth day of life. The BVD virus was isolated from all 3 calves and persisted up to 93 days in 1 calf, indicating either that BVD was transmitted in utero or via the dam's milk. Three specific pathogen free (SPF) calves permitted dams' colostrum for the first 4 feedings and then given milk replacer were exposed orally on the day of birth to BVD virus. One calf died of neonatal enteritis 28 hours post-exposure and at necropsy the BVD virus was isolated from several of its organs. The remaining 2 calves had a mild diarrhea persisting to the eighth day of age. Two calves permitted dams' colostrum ad lib. for 72 hours, and then weaned, were exposed orally to BVD virus. Both calves had a mild persistent diarrhea and BVD virus was isolated from their blood for 56 days post-exposure. Of 13 SPF, colostrum-deprived calves exposed orally or intranasally at birth to the BVD virus, 4 had severe diarrhea and died of neonatal enteritis from 38 hours to 13 days postexposure. Isolations of BVD virus were made from several of the organs of the calves at necropsy. All of the 9 surviving calves had a moderate to severe diarrhea frequently persisting for 7 to 10 days, and BVD virus was isolated from the survivors up to 103 days postexposure. Several strains of Escherichia coli were isolated from calves after the second day of life, but were neither pathogenic for mice, nor serologically related to strains of E. coli usually associated with outbreaks of calf scours. Four colostrum-deprived SPF calves were exposed orally at birth to a strain of E. coli isolated from the intestine of the calf with the most acute symptoms and fatal neonatal enteritis. None of the four calves receiving the E. coli had diarrhea. One calf, however, had respiratory distress and died on day 5. Two SPF colostrum-deprived control calves had neither diarrhea nor respiratory distress. The above findings support the conclusion that BVD virus should not be overlooked as a primary cause of the neonatal calf enteritis complex. 相似文献
2.
Summary Calves (n = 2) born to dams with experimentally induced brucellosis, and calves (n = 4) born to dams with naturally occurring infection were examined by the delayed‐type hypersensitivity (DTH) test for possible B. abortus infection. The results were compared with the serum agglutination test, complement fixation test, and Coombs test. Five calves were nursed by their dams for 8–10 weeks after birth. One calf was separated from its dam and fed artificial milk. Three to five months after birth, four calves tested seropositive in the serologic tests. Antibodies were detected in one calf as early as 1 week after birth. The calf fed on artificial milk was seronegative 4–5 weeks after birth. All calves reacted to the DTH test antigen from week 12 until the end of the experiment, even though serologic tests were negative. We conclude that the DTH test is a valuable technique for diagnosing Brucella in calves born to infected dams. 相似文献
3.
Various systems of early post natal management of the newborn calf were examined to determine which would consistently achieve high serum concentrations of maternally derived immunoglobulins, and to examine the factors which might influence this transfer. Early assisted sucking of colostrum to satiation produced consistently high serum concentrations of absorbed immunoglobulins with a mean of 27.17 +/- 8.92 zinc sulphate turbidity (ZST) units for 100 calves. No significant increase in the serum concentrations of absorbed immunoglobulins occurred when calves, which had been assisted to suck immediately after birth, were permitted to remain with their dams and encouraged to suck again at 12 hours (29.20 +/- 9.40 ZST units). Despite early assisted sucking, a small proportion of calves may remain hypogammaglobulinaemic because of the low concentration of immunoglobulins in their dams' colostrum; leakage of colostrum from the udder before calving was the major cause of these low immunoglobulin concentrations. A highly significant correlation was demonstrated between the colostral immunoglobulin concentrations and the passively acquired serum immunoglobulin concentrations of the calves. With this intensive system of early assisted sucking the breed of the calf did not significantly influence the absorption of colostral immunoglobulins. 相似文献
4.
ABSTRACTAims: To determine if an ELISA for measurement of IgA in equine serum could be used to measure concentrations of IgA in foal faeces and to determine correlations with concentrations in the milk of the dam. Methods: Faeces from 20 Welsh Cob and Welsh Pony foals and milk from their dams were collected within 12?hours (Day 0) and at 6 days after parturition (Day 6). On Day 6, faeces could not be collected from 2/20 foals, and milk samples could not be collected from 3/20 mares. An equine IgA ELISA validated for serum and plasma was used to measure concentrations of IgA in all samples in triplicate. The precision of the assay for each sample type was determined using modified CV. Results: IgA was not detectable in 7/20 Day 0 faecal samples and in 2/18 Day 6 faecal samples. For samples with detectable IgA, the mean modified CV was 10.5 (95% CI?=?6.0–15.0)% for Day 0 faecal samples, and was 6.8 (95% CI?=?4.3–9.4)% for Day 6 faecal samples. Median concentrations of IgA in faeces on Day 0 were lower than concentrations on Day 6 (0.7?mg/g vs. 37?mg/g dry matter; p?=?0.003). Concentrations of IgA in milk and faeces on Day 6 were statistically correlated (r?=?0.59; p?=?0.006). Conclusions and clinical relevance: The IgA ELISA showed acceptable precision when used to estimate concentrations of IgA in foal faeces during the first week of life, but IgA could not be detected in 37% of meconium samples collected on Day 0. This assay may be useful for investigation of the role of maternal milk IgA in the gastrointestinal tract of neonatal foals, but further assessment of both accuracy and precision of the ELISA is required. 相似文献
5.
Hides from cattle exposed to their infested dams for known periods and from sibling cattle were examined to determine when transmission of Demodex bovis occurred in an experimental dairy herd. Five of the 7 (71.4%) calves exposed to infested dams for 2 days, all 5 calves exposed for 3 days, and 1 calf exposed for 0.5 day became infested. Sibling cattle from 6 dams were examined; each had at least 1 calf that became infested. One dam produced twins, both of which became infested.These observations indicate that calves can acquire mites from an infested dam in 0.5 day and that sibling cattle from an infested dam do not always become infested. 相似文献
6.
CASE HISTORY A 5-day-old red deer calf was submitted with tachypnoea and dyspnoea, and was reluctant to move. CLINICAL FINDINGS: Muscular damage was established via elevated creatinine phosphokinase (CPK) activities (5,000 U/L), while concentrations of Se in whole blood were low (24.8 nmol/L). The animal died despite treatment with penicillin-streptomycin and 0.1 mg/kg Se/vitamin E administered by S/C injection. DIAGNOSIS: Necropsy and histological examination of cardiac and skeletal muscle confirmed the presumptive diagnosis of congenital white muscle disease (WMD). Prophylactic administration of a Se/vitamin E commercial preparation (as above) to another calf born in the same herd one month later was associated with good health and apparently normal growth and development. CLINICAL RELEVANCE: Congenital WMD due to Se deficiency can be fatal in red deer calves. However, prophylactic administration of Se and vitamin E to neonatal calves may be beneficial for neonatal red deer calves. 相似文献
7.
Summary In a female family line of Holstein‐Friesian cattle a series of trembling calves was born within a period of ten years. All trembling animals were male; female calves appeared normal At necropsy of one calf severe degenerative lesions of spinal cord and brain white matter were observed Both myelin and axons were lost and some macrophages occurred within digestion chambers. Obviously degenerated neurones were not found The lesion was interpreted as a single recessive sex‐linked hereditary trait. 相似文献
8.
ABSTRACTAims: To investigate associations between lamb growth to weaning and dam udder and teat scores measured at pre-mating, pre-lambing, docking and weaning. Methods: Mature Romney ewes (n?=?1,009) were enrolled from a commercial sheep flock located near Masterton, in the Wellington region of New Zealand in 2017. A range of udder and teat traits were scored in all ewes, using visual assessment and palpation, at pre-mating, pre-lambing, docking and weaning. During the lambing period, each newborn lamb was matched to its dam and lamb sex, birthweight and birth-rank were recorded. A rearing rank was allocated to each live-lamb at weaning, when all lambs were weighed (n?=?1,570), allowing calculation of daily growth rates (g/day). Associations between udder and teat scores and lamb growth rates to weaning were examined using multivariable models for each udder-scoring time. Results: Growth rates of lambs whose dams had udder palpation scores of hard, or both teats recorded as abnormal, pre-mating were lower than lambs whose dams had normal scores (229.9 (95% CI?=?213.2–246.6) vs. 254.5 (95% CI?=?245.6–263.5) g/day; p?=?0.011) and (227.4 (95% CI?=?208.3–246.6) vs. 247.9 (95% CI?=?235.7–260.2) g/day; p?=?0.024), respectively. Growth rates of lambs whose dams had clinical mastitis at docking or weaning were lower than those without mastitis (215.8 (95% CI?=?199.9–231.7) vs. 235.4 (95% CI?=?225.4–255.0) g/day; p?=?0.007) and (220.0 (95% CI?=?205.2–234.8) vs. 254.7 (95% CI?=?248.9–260.5) g/day; p?<?0.001), respectively. Growth rates of lambs whose dams had asymmetrical udders at docking or weaning were lower than lambs whose dams had symmetrical udders (204.6 (95% CI?=?189.7–219.5) vs. 240.2 (95% CI?=?225.4–255.0) g/day; p?<?0.001) and (223.3 (95% CI?=?213.9–232.7) vs. 242.2 (95% CI?=?229.4–255.0) g/day; p?=?0.014), respectively. Conclusions and Clinical Relevance: Pre-mating udder palpation and teat palpation scores can be used to identify ewes whose lambs are predicted to have lower growth to weaning. Assuming a mean lamb age at weaning of 84.4 days, lambs born to ewes with a pre-mating score of hard would be expected to have a mean weaning weight that was 2.1?kg less than those whose dams had normal scores. Udder palpation, udder symmetry and clinical mastitis scores during lactation were also associated with lamb growth rates. Abbreviation: CALW: Conceptus-adjusted liveweight 相似文献
9.
An outbreak of respiratory disease occurred in a central Alberta veal operation, after production capacity had been increased fourfold. Mortality rate reached 24.6% despite agressive antibiotic therapy. A review of the records revealed a cyclical disease pattern in each room. Weekly cleaning of occupied calf rooms was correlated with the disease pattern. Aerosols generated by a high pressure sprayer appeared to trigger transmission of respiratory pathogens in malnourished neonatal calves. Disease occurrence decreased and profitability increased sixfold after the introduction of the following measures: 1) discontinuing the use of the high pressure washer in the occupied calf rooms, 2) feeding calves a better quality milk replacer with supplemental milk for the poorest calves, 3) sale-yard calf purchases were abandoned in favor of direct buying. 相似文献
10.
Objectives— To report rib fracture repair in a neonatal calf using the Securos ® Cranial Cruciate Ligament Repair System (SCCLRS). Study Design— Case report. Animals— A 2-day-old female Holstein calf with fracture of right ribs 4–10. Methods— On the day of admission the calf was anesthetized and rib fractures were repaired using open reduction and the SCCLRS. Results— Rib fractures were successfully stabilized and the calf discharged from the hospital 8 days postoperatively. Conclusions— Modification of previously reported use of the SCCLRS to repair rib fractures in foals was required because of the different anatomy in the calf. This new technique was rapidly and easily performed for a large number of fractured ribs in this case. Clinical Relevance— Effective rib fracture repair in calves can be readily performed using the SCCLRS with modification of the technique reported in foals. 相似文献
11.
Abstract AIM: To assess the occurrence of Cryptosporidium oocysts in faecal specimens from foals, and investigate an outbreak of neonatal cryptosporidiosis in foals revealed in the course of the study. METHODS: Faecal specimens from foals received by a diagnostic veterinary laboratory in New Zealand between 2006 and 2007 were submitted to Massey University and tested microscopically for the presence of Cryptosporidium oocysts. The Cryptosporidium isolates in the oocyst-positive specimens were genetically identified to species level. In addition, specimen submission data from the participating laboratory for 2005–2007 were examined. In the course of the study, the identification of one Cryptosporidium-positive specimen triggered an on-farm investigation. RESULTS: Twelve faecal specimens submitted by the participating laboratory between 2006 and 2007 were tested further, and three were positive for C. parvum. Specimen submission records indicated a total of 67 faecal specimens were tested for Cryptosporidium by the participating laboratory between 2005 and 2007; 12 (18%) were positive. The on-farm investigation on a broodmare farm revealed a high incidence of neonatal diarrhoea in foals; C. parvum was the only enteropathogen found in the faeces of 4/4 affected foals examined. The diarrhoea in all those foals was self-limiting, manifesting during the second week of life, resembling foal heat diarrhoea, and accompanied by a short but intense period of shedding oocysts. CONCLUSIONS AND CLINICAL RELEVANCE: The fact that Cryptosporidium parasites were identified in 18% of faecal specimens from foals analysed for this agent in 2005–2007 by the participating laboratory indicated that infection with this agent in foals is not uncommon. Collectively, the results of this and previous studies performed in New Zealand indicate C. parvum is a cause of diarrhoea in newborn foals, potentially accounting for a proportion of cases empirically diagnosed as foal heat diarrhoea. It is therefore advisable to take precautions when handling diarrhoeic foals, until this potentially zoonotic agent is ruled out in the laboratory. 相似文献
12.
Many experimental infection studies with bovine immunodeficiency virus (BIV) have been conducted, but neither virus transmission under natural conditions nor longitudinal clinical effects of naturally occurring infections in non-experimental populations are well explored. We tested the hypotheses that BIV is transmitted across the placenta during gestation and that intragestionally infected calves are at increased risk of neonatal disease. A cohort of 59 dairy cows on one farm were enrolled at parturition and the BIV serostatus of the cows and their pre-colostral calves determined with an indirect fluorescent-antibody assay. Moreover, the enrolled calves were monitored thrice weekly for specific clinical signs through the duration of the 30 day neonatal period and the occurrence of clinical signs analyzed for association with calf pre-colostral BIV serostatus and dam BIV serostatus. Confounding due to calf passive immunity and season of birth were also explored. Forty percent of seropositive cows (14/35) gave birth to seropositive calves but no seropositive calves (0/19) were born to seronegative dams (estimated relative risk 16, 95% exact confidence interval 2.6–5.8×10 29). Calf pre-colostral BIV serostatus was not associated with the occurrence or frequency of clinical signs — but dam BIV serostatus was associated with the odds of occurrence of calf hyperthermia and with the frequency of occurrence of calf hyperthermia and hyperventilatory events. This study is inconclusive about the effects of prenatal BIV infection on neonatal health — but it does provide evidence for the natural occurrence of transplacental BIV infection. 相似文献
13.
Definitive recommendations regarding the best method to treat the diarrheic calf cannot be made at this time. The exact recommendation will probably depend on the situation. At the present time, I do not believe it is detrimental to withdraw milk from the diet for periods up to 24 to 36 hours, as long as the calf is in good condition and is returned to a full ration (maintenance plus) of milk within 3 to 5 days from the start of milk withdrawal. Milk withdrawal is most likely to be beneficial in those situations in which the calf is depressed and has lost its sucking reflex. Oral electrolyte solutions should be fed at the rate of 4-6 L/day if diarrhea is profuse or if the calf is depressed. As the calf feels better and the severity of diarrhea decreases, the amount of oral electrolyte solution can be reduced. It is sensible to continue feeding oral electrolyte solution, perhaps at the rate of 2 L/day, as long as the calf scours. Products containing 40-80 mEq/L of alkalizing agent give the best results. The higher concentrations may be more effective in older calves. Products containing bicarbonate or metabolizable base can be used when the calf is held off milk, whereas only solutions that contain a metabolizable base should be used if the calf is fed milk that day. Milk withdrawal may only be beneficial in calves that are losing their interest in sucking. Early reintroduction to milk and avoidance of milk deprivation in bright calves will help maintain condition and may boost immune function and mucosal repair. Calves that are held off milk for more than 2 days and calves that are deprived of milk while in poor condition should be fed a high-energy electrolyte solution. Beef calves tend to be treated while they are still on the dam, and if they are separated from the cow, it is usually only for a short period. This maintains the cow's lactation and maternal instincts. Cow's milk is better digested than many milk replacers and is available at a steady rate because calves suck frequently. Calves maintained on cow's milk should be fed an oral electrolyte solution containing a metabolizable base. Gastric fill from the electrolyte solution will tend to reduce milk consumption. It is important to prevent the calf from gorging on milk, which sometimes happens when a calf that is depressed and not sucking regains its appetite and has access to a very full udder. Cows that have been separated from their calf or that have distended udders should be milked out. 相似文献
14.
Neonatal calf mortality is a major concern to livestock sector worldwide. Neonatal calf diarrhoea (NCD), an acute severe condition causes morbidity and mortality in calves. Amongst various pathogens involved in NCD, E. coli is considered as one of the major causes. The study was targeted to characterize E. coli isolates from neonatal calves for diarrhoeagenic Escherichia coli (DEC) types (pathotyping), antimicrobial resistance (AMR) profiling and to correlate with epidemiological parameters. From neonates, a total of 113 faecal samples were collected, out of that 308, lactose fermenting colonies were confirmed as E. coli. Pathotypable isolates (12.3%) were represented by STEC (6.1%), EPEC (2.9%), ETEC (1.9%), EAEC (0.9%) and EHEC (0.3%). Occurrence of STEC was more in non-diarrhoeic calves, whereas ETEC was observed more in diarrhoeic calves. EPEC occurrence was observed in both diarrhoeic and non-diarrhoeic calves. Fishers extract test showed no significant association for occurrence of DEC types to type of dairies, health status, species, breed, age and sex of neonatal calves. Two hundred and eighty isolates were tested for antimicrobial susceptibility. The isolates showed maximum resistance towards ampicillin (55.4%) followed by tetracycline (54.3%), while minimum resistance was observed towards meropenem (2.5%). Multidrug resistant E. coli isolates were found to be 139 (49.6%), and Extended-spectrum beta-lactamase (ESBL) producers were 120 (42.9%). DEC pathotypes like STEC, ETEC, EHEC and EAEC that are also multidrug resistant present in neonatal calves have zoonotic potential and hence are of public health significance. 相似文献
15.
Summary A calf persistently infected and immunotolerant to Bovine Virus Diarrhoea virus (BVD virus) was, on purpose, introduced to a herd of heifer calves over 4 months of age that had been reared as recipients for embryo transplantation. All calves were brought in contact with the persistently infected animal. In total, 240 calves were involved in this experiment, 22 of which were serologically negative when introduced. These serologically negative animals developed antibodies against BVD virus within 5 months after introduction. At short distances from the persistently infected BVD virus shedder, negative calves seroconverted within 2 months, but at greater distances the moment of seroconversion was unpredictable. The calves that had undergone a natural infection with BVD virus received embryos after transportation to an allied farm. In total, 14 calves were born after embryo transplantation, all of which were free of BVD virus, in spite of the presence of BVD‐virus on the latter farm. 相似文献
16.
Abstract CASE HISTORY: A 6-week-old German Holstein heifer calf (Case 1) and a 4-week-old Charolais bull calf (Case 2) were referred because of unilateral hind limb lameness. Both had been treated with systemic antibiotics by the referring veterinarian. CLINICAL FINDINGS AND DIAGNOSIS: Based on the results of clinical, radiographic and ultrasonographic examination, a diagnosis of chronic purulent septic gonitis with subchondral osteolysis of the lateral femoral condyle was made in both calves. In Case 2 the lateral tibial condyle also showed osteolysis. TREATMENT AND OUTCOME: Treatment consisted of arthrotomy with debridement of abnormal bone and cartilage via a craniolateral and a caudolateral approach. Case 1 was discharged from with grade 1/5 lameness 60 days after surgery. In a follow-up 15 months postoperatively, the owner reported that it had been bred at 14 months, was not lame and the affected stifle joint appeared normal. Case 2 had grade 2/5 lameness 52 days after surgery, but was sound at the time of slaughter at 22 months of age. CLINICAL RELEVANCE: Arthrotomy via a caudolateral approach is a suitable method for the treatment of septic purulent gonitis with osteolysis of the lateral femoral and tibial condyles in calves. In these cases, this treatment resulted in the elimination of localised inflammation, prevented clinically relevant spread of infection to other organs, and restored normal joint function. 相似文献
17.
Neonatal calf diarrhoea remains the most common cause of morbidity and mortality in preweaned dairy calves worldwide. This complex disease can be triggered by both infectious and non-infectious causes. The four most important enteropathogens leading to neonatal dairy calf diarrhoea are Escherichia coli, rota- and coronavirus, and Cryptosporidium parvum. Besides treating diarrhoeic neonatal dairy calves, the veterinarian is the most obvious person to advise the dairy farmer on prevention and treatment of this disease. This review deals with prevention and treatment of neonatal dairy calf diarrhoea focusing on the importance of a good colostrum management and a correct fluid therapy. 相似文献
18.
Extract T he cause of scouring in young calves in New Zealand is usually attributed to nutritional problems, pathogenic Escherichia coli, Salmonella spp. or coccidiosis. This paper reports findings that indicate the presence in this country of a virus that has the potential to cause neonatal calf diarrhoea. 相似文献
19.
Forty-seven cases of neonatal vertebral fractures/luxations occurred in a 21 year period (1967-1987). All of the fractures were located between the 11th thoracic vertebra and the fourth lumbar vertebra; 77% occurred at the thoracolumbar junction. All but one case was associated with a forced extraction, either unspecified (53%), mechanical (28%), or manual (17%). A weak calf or continuous recumbency since birth was the major clinical sign. Hemorrhage around the kidneys, adrenal glands, and in perivertebral muscles was a consistent necropsy finding and a useful indicator that a thoracolumbar fracture was present. In addition to the vertebral fracture, the prominent necropsy findings were subdural and epidural hemorrhage, myelomalacia, spinal cord compression or severed spinal cord, and fractured ribs. All of the calves died or were euthanized without regaining locomotory function. 相似文献
20.
A prospective study of the severity of dehydration and acidosis was carried out in 42 calves under 35 days of age presented for treatment of neonatal diarrhea. Clinically the mean level of dehydration was 8 to 10%. The plasma volume was 65% of that in the hydrated calf but the calves only gained 6.5% in weight during therapy. Calves under eight days of age often had a lactic acidosis. Blood pH was 7.118±0.026 (mean ± 1 standard error), bicarbonate concentration 18.8±1.3 mmol/L, base deficit 11.4±1.7 mmol/L and lactate of 3.6± 0.06 mmol/L. Calves over eight days usually had a nonlactic acidosis. Blood pH was 7.042±0.021, bicarbonate 10.8±1.0 mmol/L, base deficit 19.5±1.2 mmol/L and lactate 1.2±0.3 mmol/L. These values were all significantly different from those in younger calves. Over all calves there was a poor correlation between the severity of acidosis and dehydration(r=0.05). The severity of lactic acidosis was related to the severity of dehydration. Mean bicarbonate requirements to correct acidosis were calculated to be 200 mmol(17 g of sodium bicarbonate)and 450 mmol(37 g of sodium bicarbonate)in calves under and over eight days of age respectively. Both groups of calves required a mean volume of 4L of fluid to correct dehydration. 相似文献
|
下载免费PDF全文