Crossbreeding among British and continental European dual-purpose breeds in the coastal Pacific Northwest

From 1979 through 1987, British breed and crossbred cows were mated to Simmental, Pinzgauer or Tarentaise bulls or to Hereford-Angus crossbred bulls. Beginning in 1982, continental European crossbred females also entered the herd, to be mated for first calving to Hereford-Angus or Angus bulls and as cows to continental European or Hereford-Angus bulls. In progeny of British breed and crossbred cows, dam breed effects on birth and weaning weight were not important, but continental European crossbred calves were heavier than British crossbred contemporaries at birth and weaning. Pinzgauer- and Simmental-sired calves were heavier at birth than Tarentaise crosses, but calves sired by each of the continental breeds had similar weaning weights. Maternal heterosis was greater than direct heterosis effects on weaning weight (8% vs 5%), but only direct heterosis (13%) influenced birth weight. Within progeny of continental European crossbred cows, calves with a Tarentaise maternal grandsire were lighter at birth, with no significant difference among other maternal grandsire breeds. Maternal breed effects on weaning weight were not significant. Nevertheless, in contemporary years, continental European crossbred cows reared calves that were 10% heavier than calves reared by British crossbred cows. Pacific Northwestern cattle producers could achieve substantial increases in weaning weight from introducing inheritance from continental European dual-purpose breeds into cow herds and calf crops of British ancestry.     

Prevalence of enteric pathogens in the feces of healthy beef calves

Fecal specimens from 136 healthy beef calves (1 day to 12 weeks of age) were examined for the presence of infectious agents known to cause enteric disease in calves. The calves were selected from 22 herds in which all calves were free of clinically apparent enteric disease. Salmonella sp, enterotoxigenic Escherichia coli, Cryptosporidium, and coronavirus were not detected in any of the calves. Three calves were infected with rotavirus and 1 calf was infected with Yersinia enterocolitica. Campylobacter-like bacteria were isolated from 50 of 130 calves, with 36 of the calves positive for C jejuni. Seemingly, clinically normal calves may be infected more often with enterotoxigenic E coli, Cryptosporidium, coronavirus, or rotavirus in herds in which some calves have enteric disease than in herds free of major enteric disease. Campylobacter jejuni was well adapted to the bovine host and was of similar prevalence in diarrheal and nondiarrheal calves. The K99 positive, nonenterotoxigenic E coli was isolated from the feces of 16 healthy calves. Information in addition to the presence of K99 antigen is useful when diagnosing enterotoxic colibacillosis in calves.     

Bovine diarrhea associated with Campylobacter hyointestinalis

An enteric disease affected 16 ruminating calves. The disease was characterized by a nonspecific, mild to severe diarrhea and wasting. Two calves died during the course of disease. C. hyointestinalis was isolated from 12 to 14 calves. The antibody titers of affected calves to C. hyointestinalis varied from 1:20 to 1:160. The disease was successfully treated with chloramphenicol.     

Experimental bovine respiratory tract disease with Haemophilus somnus

Eight calves were inoculated into the bronchus with H. somnus. Thirteen calves were inoculated with bovine respiratory syncytial virus (BRSV) and 8 days later with H. somnus. All calves developed necrotizing, suppurative, lobular bronchopneumonia and pleuritis. Clinical signs of disease and pneumonic lesions were significantly more severe in calves that were sequentially inoculated with BRSV followed by H. somnus. Pneumonic lesions in the inoculated calves were similar to those described for naturally occurring H. somnus-associated respiratory tract disease. Control calves inoculated with BRSV alone or sham-inoculated with medium did not develop clinical signs of respiratory tract disease. The BRSV-inoculated control calves developed minimal pneumonic lesions.     

Epizootology of wildebeest-derived malignant catarrhal fever: possible transmission among cows and their calves in the north-western Transvaal

The investigation involved 52 cases of wildebeest-derived malignant catarrhal fever in 1986 and 1989 in a herd of cattle kept in camps adjacent to a game farm harbouring a herd of approximately 330 blue wildebeest (Connochaetes taurinus). In the outbreaks, 34 cows and 18 calves died as result of the disease. The exceptionally high incidence of the disease in both cows and their calves, the low incidence in calves of unaffected cows, the relatively short period between the death of cows and their calves as well as the occurrence of the disease in 2 calves born after their mothers had been moved away from wildebeest, are indicative of transmission among cows and calves. The death of at least 6 calves within 6 weeks of birth is ascribed to intra-uterine infection while some calves that survived longer may have acquired the infection from other cattle or from wildebeest.     

The relationship between total protein in serum, glutaraldehyde coagulation test and disease in feedlot calves

Serum from in all 249 calves were used to correlate the level of total protein (serum-Tp), gamma-globulin and the reaction of glutaraldehyde coagulation test (GCT) to each other. Further, of the 249 calves 219 were bled within two days after arrival to a feedlot and serum-Tp and GCT were related to subsequent diseases. The results revealed a close relationship between the three tests. Of the 219 calves 15% had a negative GCT (hypogammaglobulinemia) and 26% had a serum-Tp below 55 g/l. There was a significantly (p less than 0.001) higher disease frequency, 81%, in the GCT negative calves than in the GCT positive, 35%. Serum-Tp was significantly (p less than 0.001) higher in healthy compared to diseased calves. The mean values were 60.6, 57.2, 55.2 and 53.1 g/l for healthy calves, calves with respiratory disease, enteritis and both respiratory disease and enteritis respectively. Further, calves with a serum-Tp below 55 g/l developed disease earlier after arrival to the feedlot than those above this limit. It was concluded that both serum-Tp and GCT can be used in field investigation to identify calves predisposed to disease.     

牧场犊牛发病次数与生长发育的关系

通过对全国157 个规模化牧场在2020年1—12 月出生的220 日龄内母犊牛各阶段发病次数、体重和日增重进行分析,旨在研究犊牛不同阶段发病次数对其后期体重、日增重的影响。结果表明:(1)断奶前后,60 日龄内发病次数≥2 次的犊牛,61~129 日龄体重、日增重极显著低于未发病犊牛和发病次数为1 次的犊牛(P<0.01);(2)转育成时,60 日龄内发病次数≥2 次的犊牛,转育成171~219 日龄体重极显著低于未发病犊牛和发病次数为1 次的犊牛(P<0.01);60~179 日龄发病次数≥1 次,转育成171~219 日龄体重和转育成日增重极显著低于未发病组(P<0.01)。因此,犊牛发病次数越多,后期生长发育越缓慢,建议牧场重视并加强犊牛断奶前后和转育成的饲养管理,做好疾病防治,以减少发病次数。     

THE SUSCEPTIBILITY OF YOUNG AND NEWBORN CALVES TO BOVINE EPHEMERAL FEVER VIRUS

The pathogenicity of a field strain, 417, of bovine ephemeral fever (BEF) virus for newborn and young calves was investigated. Three colostrum-deprived newborn calves inoculated intravenously developed severe clinical disease and viraemia, and produced long-lasting neutralising antibody. The incubation period in these animals was 10 and 11 days, compared with 5 to 7 days for older calves. Two newborn calves which received colostrum from immune dams and 2 which received colostrum from non-immune dams failed to respond clinically to intravenous inoculation with strain 417. The neutralising antibody response of these calves was of short duration. Four calves, 7 to 8 weeks old and lacking detectable neutralising antibody to BEF virus, or having low levels of antibody, did not develop clinical disease when inoculated intravenously. Four calves 12 to 14 weeks of age and free of detectable neutralising antibody to BEF virus developed clinical disease when inoculated with strain 417.     

Protection against respiratory disease in calves induced by vaccines containing respiratory syncytial virus, parainfluenza type 3 virus, Mycoplasma bovis and M dispar

A field trial to assess the ability of two vaccines to protect calves against respiratory disease was carried out on a large beef rearing unit in southern England over the two winters of 1983 to 1984 and 1984 to 1985. A quadrivalent vaccine containing the killed antigens of respiratory syncytial virus, parainfluenza virus type 3, Mycoplasma bovis and M dispar or a vaccine containing only the respiratory syncytial virus component were inoculated into 246 and 245 calves, respectively; 245 calves remained as unvaccinated controls. The calves were reared in seven batches and outbreaks of disease occurred in five; significant protection was achieved in the four batches in which disease was associated with respiratory syncytial virus and M bovis infection, together or independently. The death rate from pneumonia was 9 per cent in the control group, 2 per cent in the calves inoculated with the quadrivalent vaccine (P less than 0.001), a protection rate of 77 per cent, and 3 per cent in the calves inoculated with the respiratory syncytial virus vaccine (P less than 0.01), a protection rate of 68 per cent. The proportion of calves receiving treatment for respiratory disease was 38 per cent in the control group, 25 per cent in the calves inoculated with the quadrivalent vaccine (P less than 0.001) and 27 per cent in the calves inoculated with the respiratory syncytial virus vaccine (P less than 0.01). The results show that protection against respiratory disease can be achieved by parenteral vaccination of calves with the appropriate inactivated microorganisms.     

Conglutinin and immunoconglutinin titers in stressed calves in a feedlot

OBJECTIVE: To determine whether increased conglutinin titers are evident in stressed calves that do not develop respiratory tract disease in feedlots, compared with respiratory tract disease, and to determine the increase in immunoconglutinin titers. ANIMALS: 101 mixed-breed beef calves. PROCEDURE: Calves were processed at 4 farms of origin and allowed to remain with their dams for another 100 days. Calves from each farm were brought to a centrally located order-buyer barn. In a feedlot, 101 calves were assigned to pens and observed daily for clinical signs of acute respiratory tract disease. When sick calves were detected, they were treated with antibiotics and isolated in a pen for 4 days. Conglutinin and immunoconglutinin titers were determined for all calves. RESULTS: During the 28-day study, 73 calves developed respiratory tract disease, whereas 28 calves remained healthy. Mean conglutinin titers differed significantly among calves from the 4 farms. Significant differences were not detected in conglutinin titers among calves on the basis of sex, morbidity, or vaccination status against Mannheimia haemolytica at each farm, the order-buyer barn, or the feedlot on days 8, 15, and 28 after arrival. Immunoconglutinin titers in calves differed significantly among farms and morbidity status. CONCLUSIONS AND CLINICAL RELEVANCE: Mean conglutinin titers in calves do not appear to be associated with the incidence of acute respiratory tract disease; however, increased immunoconglutinin titers appear to be associated with recovery of stressed calves from respiratory tract disease during the first 15 days after arrival in a feedlot.     

Hematologic values in newborn beef calves.

Hematologic values were determined in 35 beef calves at birth, at 24 and 48 hours, and in 22 of these calves at 3 weeks after birth. Thirty calves did not have clinical signs of disease throughout the 3-week period. Variables that changed significantly over time in these healthy calves included hematocrit, RBC count, hemoglobin concentration, mean cell volume, mean cell hemoglobin concentration, WBC count, neutrophil-to-lymphocyte ratio, and plasma total protein and serum immunoglobulin concentrations. Of the 35 calves, 5 had clinical signs of disease at 3 weeks. Comparison of hematologic values from these calves with values for healthy calves revealed significant differences at each sample collection time, although disease was not evident at the 3 early sample times. The band neutrophil count and the neutrophil-to-lymphocyte ratio differed between the 2 groups at birth. At 24 hours, the monocyte count was higher in the 5 ill calves. At 48 hours, total leukocyte, mature neutrophil, and monocyte counts, and neutrophil-to-lymphocyte ratio also were higher in the 5 calves. At 3 weeks when clinical signs of disease were detectable in the 5 calves, the total leukocyte, band neutrophil, and mature neutrophil counts, neutrophil-to-lymphocyte ratio, and plasma total protein and fibrinogen concentrations were higher.(ABSTRACT TRUNCATED AT 250 WORDS)     

The use of immunomodulators in the control of infectious bovine rhinotracheitis

Three experiments have been carried out to verify the effectiveness of an immunomodulator, Baypamun (Bayer AG) in limiting the spread of Bovine herpesvirus-1 (BHV-1), the causal agent of infectious bovine rhinotracheitis (IBR). In the first experiment, four calves infected with BHV-1 developed severe disease whereas four calves given Baypamun simultaneously with the virus had less severe disease. Four other calves in contact with the infected calves became severely ill but another four given Baypamun were only mildly affected. In the second experiment three calves infected with BHV-1, which reacted with typical disease, were allowed to remain in contact with six calves. All six calves were given Baypamun at various times following the exposure to BHV-1 infection and all showed a much reduced reaction with two treated for 4 days developing no clinical disease. Finally, in the third experiment one calf vaccinated one month before the start of the experiment did not develop any signs of disease when housed together with a calf experimentally infected with BHV-1. Of four other calves, vaccinated when the infected calf showed the first signs of disease, only the two given Baypamun in addition to the vaccine, were protected from clinical disease whereas the two given vaccine only developed classical signs of IBR. In the three experiments the virus shedding by the Baypamun-treated calves resulted to be significantly reduced.     

A Three Year Field Study of Preconditioning Native Illinois Beef Calves Sold Through a Cooperative Marketing Association — 1969 to 1971

During the fall of 1969, 1970 and 1971, Central Illinois practitioners preconditioned (PC) 1,576 beef calves at a cost range of $3.02 to $4.72. The PC program included weaning calves 30 days before sale, having calves eating grain from a bunk and drinking from a tank, vaccinated against blackleg, malignant edema, infectious bovine rhinotracheitis (IBR) and bovine parainfluenza virus (PI3). Calves were tagged in the right ear with the green certified preconditioned for health (CPH) tag of the American Association of Bovine Practitioners. Bovine virus diarrhea (BVD) vaccine was added to the program in 1970 and 1971 since clinical cases of the disease occurred in PC calves not receiving the vaccine in 1969. Intranasal PI3 vaccine and Pasteurella hemolytica and multocida bacterin was added to the 1971 program to attempt better immunization. In 1969, more PC than non-preconditioned (NPC) calves were treated for acute respiratory disease after sale. The 1970 study showed that fewer PC than NPC calves were treated for acute respiratory tract disease. The 1971 finding showed the greatest differences. A comparison of 389 PC and 227 NPC calves sold at auction in 1971 and moved into the same feedlots showed a statistically significant reduction in number of cases of acute respiratory tract disease treated in PC calves. Generally, PC calves sold at a higher price than NPC calves.     

A severe outbreak of respiratory tract disease associated with bovine respiratory syncytial virus probably enhanced by vaccination with modified live vaccine

A severe outbreak of respiratory tract disease associated with bovine respiratory syncytial virus (BRSV) on a large beef-fattening farm is described. The outbreak started two days after five- to seven-month-old calves were vaccinated with a modified live BRSV vaccine. The disease ran a very severe course among five- to seven-month-old vaccinated calves, but disease was absent in eight-month-old an older non-vaccinated calves. The presence of IgM antibodies in sera of non-vaccinated calves indicated that BRSV was spreading on the farm between two to 15 days before the day of vaccination. The data indicate that vaccination with modified live vaccine during the course of a natural infection may enhance the severity of disease. The possible pathogenesis of the disease is discussed.     

Plasma Atrial Natriuretic Peptide in Healthy Calves and Calves with Congenital Heart Disease

Background: The basic and clinical implications of evaluating plasma atrial natriuretic peptide (ANP) concentration in calves are unknown.
Objective: To investigate the relationship between the plasma ANP concentration and left ventricular end-diastolic pressure (LVEDP) in healthy calves subjected to volume overload (Study 1), and to compare the plasma ANP concentration in calves with or without heart disease (Study 2).
Animals: Six healthy calves were used in Study 1; disease calves and sick calves with (n = 9) and without congenital heart disease (CHD) (n = 9) were used in Study 2.
Methods: In Study 1, LVEDP in anesthetized calves was manipulated by IV administration of acetated Ringer's solution (rate of 100 mL/kg/h for 20 minutes) and furosemide. In Study 2, disease calves were identified by blood examination and echocardiography or pathological examination. The plasma ANP concentration was determined by a chemiluminescence enzyme immunoassay for human α-ANP.
Results: In Study 1, preloading significantly increased the plasma ANP concentration (36 ± 20–185 ± 156, P < .01) and LVEDP (−11 ± 7–2 ± 12, P < .01) from the baseline. Furthermore, plasma ANP concentrations were strongly correlated with LVEDP ( r = 0.61). In Study 2, the plasma ANP concentration was significantly higher in the calves with CHD than in the calves without heart disease (220 [67–970] versus 31 [10–86]; mean [range], P < .001).
Conclusions and Clinical Importance: Measurement of plasma ANP concentrations in calves can provide additional information useful for predicting hemodynamic abnormalities.     

Field trial of theophylline in cattle with respiratory tract disease

A field trial was conducted to determine the efficacy of theophylline in relieving respiratory distress associated with bovine respiratory disease complex (shipping fever). Theophylline (as aminophylline capsules) was administered PO at a dosage of 28 mg/kg of body weight daily for 3 days to 20 calves with naturally acquired disease. Twenty similarly affected calves from the same group were given a placebo, and all calves were administered antibiotics concurrently. Respiratory rate and rectal temperature decreased and physical appearance improved in both groups of calves and was attributed to antibiotic administration or to natural remission of the disease. Five of the calves administered theophylline died; however, no calves administered the placebo died. Plasma theophylline concentration was greatly increased, compared with that determined in clinically normal calves in a pilot study. Bovine respiratory tract disease and/or concurrent antibiotic administration appear to cause such a rapid accumulation of lethal concentration of theophylline that its use should be restricted to hospitals capable of monitoring plasma theophylline concentration.     

Performance, survival, necropsy, and virological findings from calves persistently infected with the bovine viral diarrhea virus originating from a single Saskatchewan beef herd.

Fifty-one calves from 652 cows and heifers that calved on a Saskatchewan ranch in 1992 were identified as persistently infected with bovine viral diarrhea virus (BVDV), based on virological and necropsy findings. Herd records suggested a further 20 calves that died between birth and weaning were probably also persistently infected. Subsequent to weaning, all surviving persistently infected calves were transferred to one pen in a 10,000 head commercial feedlot, to mimic normal management practice in western Canadian beef herds. On average, when compared with healthy, BVDV-negative herdmates, persistently infected calves were "poor doers" and had poor survivability, with only 4 persistently infected calves surviving to 1 year of age. There was no difference (P > 0.05) in survival between male and female persistently infected calves. The clinical, pathological, and virological findings from these persistently infected calves varied over time. The majority of persistently infected calves had gross pathological lesions at necropsy, consistent with mucosal disease. However, approximately 25% of the persistently infected calves had gross pneumonic lesions at necropsy, with no or only mild lesions of mucosal disease. A wide variety of other lesions were also noted in persistently infected calves at necropsy. Therefore, the possibility that BVDV-induced lesions can be misdiagnosed is very real. The results of this study indicate that persistent infection with BVDV should always be considered in calves with chronic ill thrift, chronic enteritis, or respiratory disease.     

Experimental Salmonella typhimurium infection in calves.

The paper describes the clinical, bacteriological and pathological findings in experimental Salmonella typhimurium infection in calves. Oral doses of 10(8) and 10(9) organisms produced clinical disease and high mortality; doses ranging from 10(4)--10(7) organisms were less consistent in their action. Jersey calves appeared more susceptible to infection than Friesian calves. The clinical signs in most calves were pyrexia and a characteristic diarrhoea that lasted for up to 11 days; more severe symptoms were seen in the calves that received the higher doses. Following infection, all calves excreted S typhimurium in their faeces, the highest counts being observed in the calves that died. In the calves that survived, counts ranging from 10(2)--10(5)/g faeces occurred continuously for up to a maximum of 20 days and subsequent intermittent excretion occurred in a number of calves. In the calves that died, necrotic enteritis in the ileum and large intestine was the most striking lesion; lesions were uncommon in other organs. The findings are discussed in relation to the pathogenesis, diagnosis and control of the disease.     

Evaluation of the prophylactic potential of an immunomodulator against respiratory disease in calves

The prophylatic effect against respiratory disease in feedlot calves of an immunomodulator, based on an inactivated avipox virus preparation, was evaluated in a double blind, placebo controlled field trial. The effect of the immunomodulator on phagocytosis and on the reactivity of the lymphocytes was also tested.On the day of arrival at the feedlots and 3 days later 257 calves were injected with either the immunomodulator or with placebo. All calves were then observed for respiratory disease and treatments were recorded. The immunomodulator did not reduce the frequency of disease, compared to the placebo. Thirty percent of the calves treated with the immunomodulator and 27 % of the controls were treated with antibiotics for respiratory disease.The cell mediated immune reactivity of 7 calves treated with the immunomodulator and of 7 untreated calves was tested. Monocytes isolated from the animals were examined for their ability to ingest latex beads and lymphocytes from the animals were examined for their response to different mitogens. Sera from each of the two groups were also investigated for the effect on phagocytosis. No difference in these parameters was observed between the two groups.     

Effect of human leukocyte A interferon on prevention of infectious bovine rhinotracheitis virus infection of cattle

Human leukocyte A interferon was evaluated for its ability to prevent infectious bovine rhinotracheitis virus-induced respiratory tract disease in cattle. Weanling calves were treated daily for 1 week with 50 X 10(6) U of interferon, intranasally (by nebulization) and IM, and inoculated with infectious bovine rhinotracheitis virus on the first day of treatment. Respiratory tract disease was less severe in treated as compared with nontreated calves which were given only infectious bovine rhinotracheitis virus, and infection in the treated calves occurred later than in the untreated calves. Viral shedding and appearance of viral neutralizing antibodies occurred later in treated calves than in calves given only virus. Because several calves in a treatment group were housed together, whether the late appearance of infection in some interferon-treated calves was due to emergence of suppressed virus or to horizontal transmission from calves shedding virus could not be determined. One calf in the interferon-treated group developed antibody to human interferon and a few treated calves had transient elevation of hepatic enzymes. Interferon-treated calves developed a high temperature which subsided on termination of treatment. Production of disease was considerably dependent on the amount of virus and interferon given, since calves given 300 times more virus and approximately half as much interferon showed no evidence of protection against infection.