Prevalence of bovine group A rotavirus shedding among dairy calves in Ohio.

Fecal samples were collected from 450 neonatal calves, ranging from 1 to 30 days old, between May, 1988 and May, 1989 to estimate the prevalence of bovine group A rotavirus in a stratified random sample of Ohio dairy herds. Calves were from 47 dairy herds chosen to be representative of Ohio herds. Bovine group A rotavirus was detected in fecal samples by a cell culture immunofluorescence test (CCIF) and ELISA. Of 450 samples tested, 46 (10%) were positive by CCIF and 67 (15%) were positive by ELISA. The agreement beyond chance between the 2 assays was good (kappa = 0.65). The overall prevalence rate of rotavirus shedding was 16.4% (74/450). Forty-three percent (29/67) of the samples positive by ELISA were subgroup 1, none were subgroup 2, and the remaining 57% (38/67) could not be assigned to either subgroups 1 or 2. Thirty herds (62.5%) had at least 1 group A rotavirus-positive calf (mean number of samples per positive herd = 12.4), and 17 herds (37.5%) had no rotavirus-positive calves (mean number of samples per negative herd = 6.0). A live oral rotacoronavirus vaccine was used in neonatal calves of only 1 herd and 3 of 17 (17.6%) calves from this herd were positive for group A rotavirus. The percentage of the rotavirus-positive fecal samples from all calves (n = 450) when stratified by fecal consistency was as follows: 28.3% (13/46) had liquid feces; 25.6% (10/39) had semiliquid feces; 23.4% (22/94) had pasty feces; and 10.7% (29/271) had firm feces.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diarrhoea in dairy calves reduced by feeding colostrum from cows vaccinated with rotavirus

Forty-two dairy calves remained with their dams for two days after birth, and then were removed to a calf rearing shed. Calves were allocated to three groups for the next 14 days, and received twice daily either whole milk, whole milk with a 10 per cent supplement of pooled normal bovine colostrum or whole milk with 10 per cent supplement of colostrum from cows vaccinated with rotavirus. A natural outbreak of diarrhoea occurred, affecting 28 of the 42 calves. Feeding immune colostrum delayed the onset of diarrhoea, and reduced its incidence, duration and severity. Live weight gains were consequently improved. The group fed normal colostrum had diarrhoea intermediate in severity between that of control calves and those fed immune colostrum. The aetiology of the diarrhoea was complex, with calves excreting rotavirus, enteropathogenic Escherichia coli and cryptosporidia.     

Cross-sectional study of the G and P genotypes of rotavirus A field strains circulating in regularly vaccinated dairy cattle herds

Tropical Animal Health and Production - Neonatal diarrhea is the main cause of morbidity and mortality in calves up to 30 days old, and rotavirus A (RVA) is the main viral etiology. RVA...     

A longitudinal study of bovine coronavirus enteric and respiratory infections in dairy calves in two herds in Ohio

This prospective longitudinal study examined the epidemiology and disease syndrome associated with bovine coronavirus (BCV) infections in a cohort of 8 conventional calves from 0 to 120 days of age, in two dairy herds in Ohio. The periods of respiratory shedding of BCV were determined by direct immunofluorescent (DIF) staining of nasal epithelial cells and ELISA of nasal swab supernatant fluids. The periods of fecal shedding of BCV were determined by ELISA and immunoelectron microscopy (IEM). The isotype-specific antibody titers to BCV in serum (at selected intervals between 0 and 120 days of age) and the post-suckling (24 to 48 h after birth) total immunoglobulin levels were examined by ELISA and zinc sulfate turbidity tests, respectively. Of the 8 calves studied, 4 had evidence of BCV respiratory (by DIF or ELISA) or enteric infections (by IEM or ELISA) in association with diarrhea or rhinitis, even though 7 of 8 calves showed increases in one or more serum antibody isotypes to BCV and 6 of 8 calves showed BCV respiratory or enteric antigen shedding by ELISA. Serological antibody titer increases occurred in 3 calves before 30 days of age and in 4 calves after 30 days of age; two of the latter calves had a second rise in serum antibody titers to BCV after the initial rise. A serological antibody titer increase was not observed in one calf. This suggests that BCV infections may be very common in a closed herd and may occur in older calves, although many may be subclinical and some may be recurrent. There were no statistically significant correlations between total serum immunoglobulin levels or BCV antibody isotype titers in serum (24-48 h after birth) and clinical disease or infection by BCV; however, calves with low levels of IgA BCV antibodies in serum (24-48 h after birth) had a significantly greater average number of days with diarrhea than those calves having high levels of IgA BCV-specific antibodies in serum.     

Rotavirus infections in calves in dairy herds

Neonatal calf diarrhoea was studied in 115 calves of one dairy herd from January 1976 to June 1977. Two syndromes could be distinguished: a mild and short lasting 'early diarrhoea' within the first three days of life and a usually more severe 'late diarrhoea' from the fourth to the 14th day of life. The latter type of diarrhoea occurred almost exclusively during the first half of the year. Thirty-four out of 45 calves with late diarrhoea excreted rotaviruses, whereas only one of 34 calves with early diarrhoea excreted virus. In addition, rotavirus excretion was found in 11 calves that either remained healthy or had recovered from diarrhoea before virus was first detected. Similar findings were obtained in the spring of 1978 but in addition bovine coronavirus was recovered from four calves with late diarrhoea and from three healthy calves. One faecal sample obtained from a calf with diarrhoea on day 2 yielded K99+ Escherichia coli. Nearly all cows excreted rotavirus-specific antibodies in their colostrum but no relationship was found between the initial colostral antibody titre against rotavirus and the development of rotavirus-associated diarrhoea in the calf.     

Longitudinal survey of rotavirus infection in calves

A longitudinal survey of rotavirus infection in heifer calves was carried out on a closed Friesian dairy herd over two successive calving seasons. Rotavirus was detected by electron microscopy in the faeces of 45 of 57 (79 per cent) calves examined. On average the virus was first detected at 6.1 days of age. Clinically the disease associated with rotavirus infection was of mild to moderate severity. Only one infected calf required intravenous fluid therapy. Diarrhoea or excretion of abnormal faeces was associated with rotavirus infection in 58 per cent of infected calves, while in the remaining 42 per cent infection was subclinical. The cycle of rotavirus infection was broken by thorough cleansing and disinfection of the calf house.     

A case-control study of Washington dairy herds experiencing drug residue violations in market calves

The purpose of this case-control study was to examine the association between management practices and the occurrence of violative drug residues in calves originating from Washington dairies. In 1992, 74 dairies were identified as first-time offenders sending to abattoirs calves less than 1 week of age that had violative residue levels. Of these, 56 answered a subset of previously validated management questions from the 1991–1992 US National Animal Health Monitoring System National Dairy Heifer Evaluation Program (NDHEP) study during a violation investigation and comprised the case group. The controls were the 51 randomly selected Washington dairies that participated in the NDHEP, completed the four NDHEP questionnaires, and had not been identified as having residue violations. Management factors investigated were those associated with maternity and pre-weaning hygiene, vaccination and preventive practices, type and management of liquid calf feed, and general management. Other factors included herd somatic cell count (SCC), the presence of clinical signs associated with diseases of body systems, and herd size. Significant associations were detected between violation occurrence and the management of calving cows, colostrum volume and management, and the person responsible for calf care. Significant associations but of the wrong direction were found between violation occurrence and type and management of liquid calf feed. No significant associations were detected between violation occurrence and the remaining management factors, herd size, animals entering the herd, or SCC.     

Longitudinal prevalence study of diarrheagenic Escherichia coli in dairy calves

A longitudinal study (cohort study) elaborating 1,224 rectal swabs from 221 calves aging between 1 and 12 weeks was conducted on 11 dairy farms (i) to ascertain associations between diarrhea and shedding of diarrheagenic E. coli and (ii) to facilitate the zoonotic potential assessment of E. coli strains shed by young calves. Calves were screened weekly by PCR of swab cultures for shedding of enterotoxigenic E coli [ETEC; by detection of heat stable (est) and heat labile enterotoxin genes (elt)], diffusely adhering E. coli [DAEC; diffuse adhesion (daa)], typical enteropathogenic E. coli [EPEC; bundle-forming pili (bfpA) and intimin (eae)] as well as enterohemorrhagic E. coli [EHEC, intimin (eae) and Shiga toxin (stx)]. In addition, EHEC-hemolysin- (Hly(EHEC)) and alpha-hemolysin- (alpha-Hly) producing E. coli were detected by inoculation of blood agar plates. Within the 221 calves, prevalences were 69.7% (25.2% of the 1,224 samples) for Hly(EHEC)-producing E. coli, 55.3% (19.3%) for eae, and 18.2% (4.5%) for stx. E. coli strains exhibiting an alpha-Hly phenotype were detected in 66.5% of the calves and 21.9% of fecal samples. The est gene was detectable in 31.7% of the calves from only 9 of 11 herds and in 7.8% of the samples. Calves shedding DAEC or typical EPEC were not identified. The detection frequency of virulence traits significantly depended on the calves' age and shedding dynamics differed between the traits. A significant correlation between calf diarrhea and shedding of EHEC virulence traits was determined for several postnatal periods (1 week: Hly(EHEC); 1st & 10th week: eae; 4th week stx). Shedding of ETEC (est) was associated with diarrhea in newborn calves (1st week) only. Hly(EHEC)- and alpha-Hly-producing E. coli were shed significantly more frequently by diarrheic calves in 1st and 8th week of life, respectively. The knowledge gained in this study highlights the high prevalence of zoonotic E. coli already in calves.The age-dependent shedding dynamic of the various E. coli pathovars has to be considered regarding prophylaxis as well as planning intervention studies, both for calves and humans.     

Protection of newborn calves against fatal multisystemic infectious bovine rhinotracheitis by feeding colostrum from vaccinated cows.

To determine whether consumption of colostrum with high levels of serum neutralizing antibody to bovine herpesvirus 1 would protect neonatal calves from the frequently fatal multisystemic form of infectious bovine rhinotracheitis, Holstein calves were fed for 48 h after birth with either pooled colostrum from seropositive vaccinated cows or colostrum from seronegative unvaccinated cows. The serum neutralizing antibody achieved in the former calves was between 64 and 256 and the titer in the latter calves was below 8. At 48 h of age the calves were challenged by aerosolization with bovine herpesvirus 1. All five seronegative calves died or were euthanized in a moribund state between days 5 and 7 of the trial, whereas all five seropositive animals remained healthy throughout the study. Twice daily clinical examination revealed significantly lower scores in the seronegative group from 60 h postinfection. Relative lung weights were greater in the seronegative group, associated with a severe acute necrotizing bronchiolitis with fibrin exudation. The seronegative group of calves also demonstrated an acute necrotizing rumenitis, pharyngitis, glossitis, esophagitis, laryngitis and tracheitis. The seropositive animals had only small areas of subacute necrotizing fibrinopurulent rhinitis. Bovine herpesvirus 1 virus was isolated from all nasal passages of all calves but isolation of virus in the seronegative calves was made from the trachea (5/5), lung (4/5), bronchial lymph nodes (4/5), spleen (4/5), thymus (3/5), liver (2/5), rumen (2/5) and brain (1/5).(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidemiology of bovine anaplasmosis in dairy herds from Costa Rica

Bovine anaplasmosis is endemic and occurs in almost all areas of livestock production of Costa Rica. The aim of this study was to determine the seroprevalence and risk factors of anaplasmosis in dairy farms of Costa Rica by the recombinant truncated MSP-5 (rMSP-5) enzyme-linked immunosorbent assay (ELISA). Serum samples were obtained from 733 cattle from 20 commercial dairy herds of Costa Rica. The overall seroprevalence was 37.2% and herd seroprevalence ranged from 20.0 to 72.0%. The age-specific seroprevalence was 49.3% in young and 33.4% in adult animals. The main risk factors associated with seroprevalence were season of occurrence of clinical cases (rainy season) (OR=22.8), presence of tabanids (OR=9.5) and stable flies (OR=6.2), stable flies control measures (OR=3.2), non-use of ear tattoos (OR=2.8), interval of veterinary visit (≤ 60 days) (OR=2.7), altitude of the farms (<800 masl) (OR=2.6) and age (<2 years) (OR=1.8). The results indicated that exposure of cattle to Anaplasma marginale is common in dairy herds of Costa Rica and endemic instability situation probably is due to inadequate vector control.     

The efficacy of colostrum from cows vaccinated with rotavirus in protecting calves to experimentally induced rotavirus infection

Calves which were continuously fed colostrum from vaccinated cows for the first ten days of life, were fully refractory to experimental infection with strain 81/36 F of bovine rotavirus. By contrast, the response to virus exposure of calves which were treated with normal colostrum was identical to that of the control calves, in that they underwent severe diarrhea and a significant slowing of the growth rate. The antibody titer in the milk of vaccinated cows tends to decline rapidly so that it no longer provides any protective effect. Two alternatives were considered feasible in improving prophylaxis for rotavirus infections: (a) the continuous feeding of calves with 1st day colostrum as part of the ration throughout the period of greatest risk (first week of life), or (b) enhancing the efficacy of the vaccine in pregnant cows to the point where antibody concentration in the milk would remain at a protective level.     

Prevalence of antibodies to Leptospira interrogans serovar hardjoin bulk tank milk from unvaccinated irish dairy herds

: Bulk tank milk samples, collected from 347 herds throughout the Republic of Ireland using a sampling frame based on seven milk-recording organisations, were tested by ELISA for antibodies to Leptospira interrogans serovar hardjo. These herds, which had not been vaccinated against leptospirosis within the previous five years, were categorised according to their province, milk-recording organisation and size. Two-hundred-and-seventy-three herds (79%) had a positive ELISA titre. Both the probability of a herd being seropositive and the antibody level in the herd milk sample were affected by the province (P < 0.05 and P < 0.01, respectively) and the herd size category (P < 0.05 and P < 0.01, respectively). Larger herds were significantly more likely to have positive reactions and higher mean concentrations of antibody. It was concluded that a high proportion of unvaccinated Irish dairy herds have been exposed to infection with Leptospira hardjo.     

Bovine rotavirus strains circulating in beef and dairy herds in Argentina from 2004 to 2010

Bovine Group A Rotavirus (RVA) is one of the main causes of neonatal calf diarrhea worldwide. The present study reports the genotyping of bovine RVA strains circulating in Argentinean cattle from 2004 to 2010. Additionally, a new set of typing primers was designed and tested to differentiate between G8 and G6 (lineage III and IV) RVA strains. Bovine RVA was detected in 30% (435/1462) of the tested samples, corresponding to 49% (207/423) of the studied outbreaks with a similar detection rates in beef (53%; 67/127) and dairy herds (52%; 65/126). The RVA strains circulating in Argentinean cattle belonged to the common bovine genotypes G6 (lineages III and IV), G8, G10, P[5] and P[11]. A different RVA G/P-genotype distribution was found between the exploitation types, with the combination G6(IV)P[5] being by fare the most prevalent RVA strain in beef herds (58%), whereas a more even distribution of G6(III)P[11] (15%), G10P[11] (17%), G6(IV)P[5] (14%), and G6(IV)P[11] (6%) RVA strains was detected in dairy herds. G8 RVA strains were found in two dairy farms in calves co-infected with G8+G6(III)P[11]. A high percentage of co-infections and co-circulation of RVA strains with different genotypes during the same outbreak were registered in both exploitation types (20% of the outbreaks from beef herds and 23% from dairy herds), indicating a potential environment for reassortment. This finding is significant because G10P[11] and G6(III)P[11] strains may possess zoonotic potential. Continuous surveillance of the RVA strains circulating in livestock provides valuable information for a better understanding of rotavirus ecology and epidemiology.     

A seroepidemiological study of bovine pestivirus in Queensland beef and dairy herds conducted in 1994/95

OBJECTIVE: To describe the distribution and prevalence of cattle herds with detectable antibody to bovine pestivirus in Queensland in 1994/95. MATERIALS AND METHODS: The study used 7,838 serum samples collected from 250 herds in Queensland, as part of a structured animal health surveillance program conducted in 1994 and 1995. Samples were collected from female cattle bred on the property. In each herd, 10 to 20 heifers less than two years of age and 10 to 15 older cows were sampled giving a 95% probability of detecting one or more seropositive animals if the seroprevalence was approximately 10% or greater. Sera were analysed for antibodies to bovine pestivirus using a virus neutralisation test. RESULTS: Total cattle numbers in sampled herds varied from 62 to 24,600 head, while total area of properties sampled varied from 50 to 395,400 hectares. Eleven percent of herds contained no seropositive animals among those sampled, and in 38% of herds, all sampled cattle aged one to two years of age were seronegative. There was a trend for larger herds to have one or more animals seropositive for bovine pestivirus (chi-squared for Linear trend = 3.656, p = 0.056). Herds with more than 500 head of cattle were significantly more likely than herds with less than 500 head to contain one or more seropositive animals in any age group (prevalence ratio = 1.12; 95% confidence interval 1.01 - 1.23; p = 0.026). Age specific seroprevalence increased from around 10% in heifers, to between 75% and 85% in cows aged 10 years. The average annual incidence risk for bovine pestivirus infection varied from 0.12 to 0.24 seroconversions per cattle year at risk, and did not vary with age. The overall crude seroprevalence adjusted for herd size was 45%. There was a wide range of seroprevalence recorded for each level of stocking intensity. CONCLUSIONS: This survey provides valuable baseline data on bovine pestivirus infection in Queensland cattle herds.     

Sucking behaviour of hand-reared newborn dairy calves

AIM: To determine the feeding ability of calves during the first 4 days after birth. METHODS: The sucking behaviour of 171 dairy calves, fed from individual bottles during the first 4 days after birth, was evaluated by quantifying the volume of colostrum consumed, the duration of feeding, and speed of drinking. Calves had been separated from their mothers and brought into a rearing shed in the morning, when < 24 h of age, and were offered 2 L colostrum from a bottle in the afternoon of the same day, and twice daily thereafter. RESULTS: Newborn calves became efficient suckers from bottles within 24 h of removal from their dams (collection). On the day after birth, 95% of calves drank the 2 L of colostrum offered during the afternoon feed, and by Day 4 virtually all calves (99%) drank this amount. Calves that had inadequate colostrum from their dam were more likely to drink all 2 L offered after collection, but a small number of calves that had not had colostrum from their dams and drank < 500 ml at the afternoon feed following collection were likely not to drink 2 L on the following days. However, calves that did not drink all 2 L on Day 1 were not disadvantaged in comparison to those that did, in that they were equally likely to drink 2 L on Day 4. CONCLUSIONS: The majority of calves became efficient drinkers within 48 hours of birth, but a small number of slow feeders may need individual feeding at least up to 4 days after birth.