Excretion of Eimeria Oocysts in Calves During their First Three Weeks After Turn-out to Pasture

The numbers of Eimeria oocysts per gram (opg) and the dry matter content of 449 faecal samples taken from 54 calves in 8 herds in south west Sweden were determined during the last 2 weeks before and the first 3 weeks after the animals were turned out to pasture. While they were housed only between 0 and 580 opg were found and in 2 of the herds the numbers of oocysts remained low after turn-out. In the other 6 herds the numbers of oocysts increased after 8 to 10 days and reached a peak of between 1080 and 80 803 opg 9 to 18 days after turnout. By 21 to 24 days after turn-out the opg-values had declined to their initial levels. Eimeria alabamensis accounted for most of the increase, but small numbers of oocysts of E. auburnensis, E. bovis, E. bukidnonensis, E. cylindrica, E. ellipsoidalis, E. pellita, E. subspherica, E. wyomingensis and E. zuernii were also observed. The interval between turn-out and the start of the increase in excretion of oocysts corresponded closely to the prepatent period of E. alabamensis and overwintered oocysts were therefore the most likely source of the infection. In 6 of the herds the dry matter content of the faeces of the calves decreased after turn-out and 56 % of the calves had clinical diarrhoea. Although it cannot be excluded that change of diet may have contributed to these symptoms, E. alabamensis infection is suggested as a potential cause of diarrhoea and loss of condition in calves in Sweden during their first weeks on pasture.     

Excretion of Eimeria alabamensis oocysts in grazing calves and young stock

The aims of the present study were to investigate the excretion of Eimeria alabamensis oocysts by young cattle during their first grazing season and during the first 16 days of their second grazing period. In trial 1, nine first-season grazing heifers were studied and found to have become infected with E. alabamensis shortly after turnout. The next grazing period they were turned out on to a permanent pasture together with two first-season grazing calves. Faecal samples were collected before turnout and then daily from day 3 to day 16. The second-season grazing heifers excreted insignificant numbers of E. alabamensis oocysts, whereas one of the two first-season grazing calves excreted up to 703,000 oocysts/g of faeces (OPG), indicating that the pasture was contaminated. In trial 2, faecal samples were collected from 12 calves before their first turnout in May, daily from day 2 to day 20 after turnout and then once a week until the end of September. The calves grazed pastures used in previous years by first-season grazing calves. Nine of the calves developed clinical E. alabamensis coccidiosis 4-7 days after turnout and excreted more than 950,000 OPG on days 9-10. By day 17 the oocyst excretion had decreased below 900 OPG and remained low throughout the rest of the grazing season. The results of the two studies indicate that reinfections with E. alabamensis are of little clinical importance in calves grazing contaminated pastures, and that young stock infected with E. alabamensis during their first grazing season may be used to cleanse contaminated pastures without risk of developing clinical coccidiosis.     

Control of bovine coccidiosis with monensin: in nonresistant newborn calves

Newborn Holstein male calves were purchased within 3 days after birth and were removed from the local farms to the Dixon Springs Agricultural Research Center. They were hand-fed for 7 weeks and then weaned to a prepared feed. Eight groups, each of 4 calves, were housed in separate pens. In each of 4 pens (pens 2 to 5), 1 calf was inoculated with sporulated oocysts of Eimeria bovis (and was not medicated); 1 calf was inoculated and given feed with added monensin at the dosage level of 10 g/906 kg of feed; and 2 calves were inoculated and given medicated feed with added monensin at the dosage level of 20 g/906 kg or 30 g/906 kg. In the 4 other pens (6 to 9), the calves were inoculated with E zuernii and otherwise were given feed without or with added monensin as in pens 2 through 5. Another group of 5 calves (all kept in 1 pen), served as noninoculated, nonmedicated controls. At 14 days after inoculations with E bovis, the single calves in each of the 4 pens that were given the nonmedicated feed began to show clinical signs of coccidiosis and discharged increasing numbers of oocysts. The other inoculated calves (given monensin) had fewer clinical signs and discharged fewer oocysts in the feces as the level of medication in the feed increased. The calves inoculated with E zuernii developed only moderately severe infections when compared with those inoculated with E bovis. Inoculated (with E bovis) nonmedicated calves had severe reductions in feed consumption and weight, and 3 of 4 died.(ABSTRACT TRUNCATED AT 250 WORDS)     

Survival of Oocysts of Eimeria alabamensis on Pastures under Different Climatic Conditions in Sweden

The extent to which oocysts of the coccidian parasite Eimeria alabamensis can survive the winter and cause clinical coccidiosis in different parts of Sweden was investigated. Fecal samples were collected between May and July 1993 from calves on 59 farms where calves had grazed the same pasture for at least 5 consecutive years. The farms were situated in 9 regions of Sweden with different climatic conditions in the winter. On each farm, 5 samples of feces were collected from the floor of the calf-house before the calves were turned out in the spring, and again from the pasture on days 4 or 5, 8 or 9 and 10 or 11 after they were turned out. Overwintering of oocysts of E. alabamensis was considered to have occurred if an increase in the excretion rate of oocysts of this species could be demonstrated 8 to 11 days after calves had been turned out to pastures that had not been grazed since the previous autumn. Oocysts were shown to have overwintered on 27 farms, representing all 9 regions. Samples from 20 (34%) of the farms representing all the climatic regions contained more than 850000 oocysts per g of feces. This was comparable with the numbers found in animals with clinical coccidiosis due to E. alabamensis. Delaying turnout until the beginning of July did not affect the infection rate of the calves. However, calves which were turned out to pastures that had been grazed by older cattle or horses, either earlier in the spring or in previous years, excreted significantly fewer oocysts than calves which were turned out to pastures that had been grazed only by calves. A questionnaire answered by 321 dairy farmers revealed that of the 298 farmers who turned their first-season grazing cattle out to traditional pastures, 179 (60%) had used the same pasture for at least 5 years. These 179 farmers had experienced a significantly higher incidence of diarrhoea in their calves during the first 2 weeks at pasture than those farmers who had used different pastures.     

Prevalence and associated management factors of Cryptosporidium shedding in 50 Swedish dairy herds

Cryptosporidium parvum is a protozoan parasite causing diarrhoea in young calves. This cross-sectional study was performed to estimate the prevalence of Cryptosporidium infected herds in a sample of Swedish dairy herds and to identify potential risk factors associated with shedding of oocysts. Fifty dairy herds, selected by stratified random sampling, were included. The herds were visited once during the indoor seasons of 2005–2006 and 2006–2007. Faecal samples were collected from 10 calves, 10 young stock and 5 cows in each herd. Clinical observations of sampled animals and environmental status were recorded, and farmers were interviewed about management procedures. Faecal samples were cleaned by sodium chloride flotation and detection of oocysts was made by epifluorescence microscopy. Cryptosporidium parvum-like oocysts were found in 96% of the herds. Prevalence was 52% in calves, 29% in young stock and 5.6% in cows. Three two-day-old calves shed oocysts. Cryptosporidium andersoni was found in seven animals from four different herds. Factors associated with prevalence of shedders among sampled animals in a herd were age at weaning, cleaning of single calf pens, placing of young stock, system for moving young stock, and year of sampling. Factors associated with shedding in calves were age, placing of young stock, routines for moving young stock and time calf stays with the cow. The only significant factor in young stock was age. In cows, number of calves in the herd and type of farming (organic vs. conventional) affected shedding.     

Investigation of Neospora sp. and Toxoplasma gondii antibodies in mares and in precolostral foals from Parana State, Southern Brazil

Infections with Eimeria parasites can lead to severe diarrhoea with considerable clinical and economic consequences in first-year grazing stock. To identify and characterise the cause of diarrhoea observed during previous years, 164 animals on 14 dairy farms in northwestern Germany were included in this study. The calves were physically and parasitologically examined prior to turnout and until 21 days post turnout (d.p.t.). Mean animal weights decreased from 194.9 kg at the start to 189.3 kg bodyweight at the end of the study. In all herds, oocyst counts were very low prior to turnout and increased after the calves had been kept on pasture for at least 7 days. On Day 9 post turnout, 90% and at the end of the study (21 d.p.t.) 70% of all animals showed Eimeria-positive faecal samples. During the course of the study, 79 (48.2%) animals passed faecal samples with more than 100,000 oocysts per gram. The predominant species identified was Eimeria alabamensis, which accounted for more than 83% of the oocysts counted. These parasitological findings matched the clinical observations. Diarrhoea was found in 130 (79.3%) of the study animals. At 5d.p.t. and thus prior to the rise of faecal oocyst counts, a significant increase in diarrhoea was recorded. Calves showing diarrhoea excreted statistically significantly more often over 100,000 E. alabamensis oocysts per gram faeces (0.28; p = 0.0002) than calves without diarrhoea. Diarrhoea was also found during significantly more study days in animals with high oocyst counts (0.39; p = 0.0001). These data indicate that in endemic areas first-year grazing calves must be considered at risk to develop clinical coccidiosis due to E. alabamensis infection during the first 2-3 weeks post turnout.     

Eimeria infections in cows in the periparturient phase and their calves: oocyst excretion and levels of specific serum and colostrum antibodies.

Faecal Eimeria oocyst excretion and levels of antibodies to first generation merozoite antigen of E. bovis in sera and colostra were followed in 86 and 70 cow-calf pairs in northern (group EF) and central Germany (group H), respectively, over periods of 3 weeks before to 3 weeks after calving in cows and from birth to an age of 63 days in calves. Oocysts were found in 30 and 7.7% of cows in groups EF and H, respectively. They belonged to 10 (group EF) and four Eimeria spp. (group H) with E. bovis, E. ellipsoidalis, E. auburnensis and E. zuerni as the most frequently occurring species. Prevalence and intensity of oocyst excretion varied with time resulting in peak values around the date of parturition, particularly in the case of E. bovis. Peak values at the time of parturition were also seen in case of strongyle egg excretion. Seven (group H) and nine Eimeria spp. (group EF) were found in the calves. The predominant species E. ellipsoidalis, E. zuerni, E. bovis and E. auburnensis were detected for the first time earlier after birth (3-5 weeks) than the others. The prevalence of Eimeria infections increased to 67.1% (group EF) and 50.1% (group H) 9 weeks after birth. Specific IgM and IgA antibody levels (the latter only determined in group EF) in cow sera remained almost constant throughout the observation period, whereas IgG(1) and IgG(2) levels were reduced at the time of parturition. Levels of specific antibodies in sera and colostra were significantly correlated. Except IgM antibodies, significant inverse correlations were found in cows between intensity of infection with E. bovis and specific serum IgG (group H) and IgG(2) (group EF) antibodies. Antibodies to E. bovis were detected in calves sera only after colostrum intake with significant correlations between levels in calves sera and colostra. Levels decreased, starting within the first week of life (most conspicuously in case of IgM and IgA) until the third week. Subsequently, but except IgG(1) antibody concentrations increased until the end of the observation period. Interrelations between antibody levels and the total amount of E. bovis oocysts excreted by the calves until the ninth week of life varied with the age of the animals. Inverse relationships in the first 3 weeks of life as suggested by negative correlation coefficients could not be proven statistically. Thus, there is no unambiguous proof for immunoprotection of calves against E. bovis via maternal immunity. Considering antibody levels in the 3-9 weeks old calves significant direct correlations with E. bovis oocyst excretion were found in case of IgM, IgG(2) and IgA, reflecting an active immune response of young calves to coccidial infection.     

Isospora orlovi infection in suckling dromedary camel calves (Camelus dromedarius) in Kenya

Outbreaks of isosporosis in young suckling dromedary camel calves (Camelus dromedarius) in Dubai, UAE and in Kenya were recently described. In the former outbreak the pathogen was shown to be Isospora orlovi by morphological features and was later characterized molecularly. In the present study, we have made a longitudinal investigation of 159 suckling dromedary calves < or =12 weeks of age belonging to 8 ranched camel herds (M1) in Northern Kenya. The study was carried out during 18 months. In three of the herds frequent samples were taken irregularly every 1-6 weeks. All calves < or =12 weeks of age present in the respective herds were sampled during the visits. In addition, 91 calves of the same age group but belonging to 42 pastoral herds (M2) in Northern Kenya were point sampled at convenience. Faecal samples from each calf were taken and the faeces were investigated for coccidia. Samples found with coccidian oocysts were suspended in a 2% potassium dichromate solution. Isospora sp. was identified and samples with relatively high numbers of Isospora sp. were analysed molecularly. The SSU rRNA gene and internal transcribed spacer 1 (ITS1) were amplified with primers complementary to conserved regions of the SSU rRNA gene in eukaryotes as well as a conserved part of the 5.8S rRNA gene of Eimeria. A relatively high number of the calves exhibited diarrhoea, 30.2% and 41.8% in the M1 and M2 herds, respectively. Isospora sp. was only found in diarrhoeic calves or in calves convalescent from recent scouring periods. No calf >8 weeks of age was found to be excreting Isospora sp. The parasite was only found in calves < or =4 weeks of age in the M1 herds and in the M2 herds in calves <8 weeks of age. Of the M1 and M2 calves exhibiting diarrhoea, 20.8% and 26.3% excreted Isospora sp., respectively. Morphologically the Isospora sp. was similar to I. orlovi and sequence analysis of the SSU rRNA gene from four Kenyan isolates (unfortunately only from the pastoral herds, M2) and ITS 1 segments from three of the isolates from Kenya and one from Dubai, confirmed that the Isospora isolates belonged to the species I. orlovi, and that the sequences were similar to the Dubai isolates.     

Quantitative determination of coccidian oocysts in beef calves from the coastal plain area of Georgia (U.S.A.)

For two consecutive years, determinations were made of the prevalence and abundance of coccidian oocysts from crossbred beef calves raised on Bahia grass pastures in the coastal plain area of Georgia. Of the 534 fecal samples collected during the survey, 461 (86.3%) contained one or more species of coccidian oocysts. The total mean oocysts per gram of feces (OPG) was significantly different (P less than 0.10) between the two years. Thirteen species of Eimeria were found during both years of the survey. Eimeria bovis was the most prevalent species found in the survey; E. ellipsoidalis, however, had the greatest number of OPG. Eimeria bukidnonensis, E. pellita, and E. brasiliensis were the least prevalent species and also had the lowest numbers of OPG. Only one clinical case of coccidiosis was seen. A nine-month-old calf had E. zuernii coccidiosis; it excreted E. zuernii oocysts in several fecal samples before the clinical disease appeared.     

Coccidia in cows and calves on pasture in north Georgia (U.S.A.)

The prevalence and abundance of coccidian oocysts were determined in a herd of beef cows and calves on fescue pastures in the Piedmont area of Georgia during 4-consecutive grazing seasons. Twelve species of Eimeria were found in the feces of the calves and 10 species were found in the feces of the cows. Eimeria bovis was the most prevalent species found in both the calves and cows. It occurred in 72.5% of 1090 samples from the calves and 10.2% of 719 samples from cows. Eimeria bovis also comprised the majority of oocysts present in the fecal samples from the calves and cows. The greatest number of E. bovis in a sample was 45 800 oocysts per gram of feces (OPG) from a calf and 1900 OPG from a cow. No cases of clinical coccidiosis were seen in any of the animals sampled during the survey.     

Experimental Infection of Newborn Calves with Coccidia and Reinfection after Weaning

Four newborn Hereford calves were orally inoculated five times with 100 sporulated oocysts of coccidia, predominantly Eimeria zurnii. Each calf was kept isolated with its dam until weaned at the age of 13 weeks. Three other newborn calves were similarly isolated but not experimentally infected. The calves were then challenged with 300,000 sporulated oocysts at the age of five, seven and nine months. The previously unexposed calves developed marked clinical coccidiosis after the first challenge, but resisted the second and third challenge. The neonatally exposed calves were susceptible to infection at the first challenge as well as to the next two challenges at seven and nine months of age, but the clinical signs following the last two challenges were milder than those of the first challenge. These findings suggest that under conditions where calves become infected with coccidia when very young, such calves may, by shedding oocysts in large numbers for long periods, be a continuing source of coccidial infections to other animals.     

The prepatent and patent periods of Eimeria alabamensis and further description of the exogenous stages

Eimeria alabamensis infections were established in calves 5 to 6 weeks of age by adminestering 10 million, 80 million, or 100 million sporulated oocysts. The prepatent period was 6 to 8 days (mean 6.6). Oocyst discharges usually lasted for 2 to 3 days although a few calves passed oocysts throughout the rest of the 3-week observation period. Calves with oocyst discharge exceeding 1 million oocysts per g of feces had a moderate diarrhea at the time of peak oocyst discharge. No other clinical signs were observed in any of the infected calves. Reinoculations with 100 million sporulated oocysts given 3 weeks after the initial inoculations of 10 million or 80 million oocysts resulted in infections characterized by greatly reduced oocyst discharges. Sporulated oocysts of E. alabamensis were 16 to 24 μ by 12 to 16 μ and were usually ovoid. The oocyst wals consisted of two layers. Sporocysts were elongate-ellipsoid, had a distinct Stieda body, and were 10 to 12 μ by 4 to 6 μ. Completely sporulated oocysts were first observed after 5 days at 25 °C, and most were sporulated after 8 days. Oocysts did not sporulate at 4 °C, 33 °C, and 37 °C.     

Dynamics of Eimeria oocyst excretion in dairy calves in the Province of Buenos Aires (Argentina), during their first 2 months of age

Clinical coccidiosis is associated with high fecal contamination and stress situations, mainly in animals under 1 year of age. Artificially fed dairy calves are one of the categories most prone to suffer from this parasitic disease. The study was carried out in a commercial dairy farm. Feces samples of heifer calves between 2 and 8 weeks old were taken monthly for oocyst counts and Eimeria spp. identification. Of the 862 feces samples analyzed, 48% presented oocysts. When grouping the results of monthly samplings of each age group, it was observed that this percentage increased in the group of calves between 20 and 40 days of life, reaching the peak average of 85% of infection prevalence in the group with between 26 and 30 days of age. The discharge of oocysts observed between 21 and 35 days of age was superior to the rest (p<0.05). This trend appeared every month throughout the whole year. However, during March, April, June, September and November, the curves in the group categories were higher than in the remaining months (p<0.05). Twelve Eimeria species were identified, being E. ellipsoidalis, E. bovis, E. zuernii and E. auburnensis those in highest numbers. E. ellipsoidalis had an important predominance in the opg composition, >75% up to 25 days of life (p<0.05). E. bovis reached peak values in the 26 and 30 days group (p<0.05), remaining without significant variations in the last stage of the artificial milk feeding period (approximately 60 days of life), when the oocyst counts were significantly low. Oocysts of E. auburnensis appeared in great proportion (46%) in the cultures later than the previous species (p<0.05), in calves of the age groups of between 46 and 50 days of age. Oocysts of E. zuernii showed no trend associated with age. The highest prevalence of infection and of oocyst values appeared during the periods with better environmental conditions for sporulation, survival and dispersion of oocysts (spring and autumn), coincident with the highest birth rates and an elevated number of calves in the paddock. Calves developed a process of natural "vaccination" against coccidiosis. This was demonstrated by the decrease in the quantity of animals shedding oocysts and in the number of oocysts eliminated at the end of the artificial milk feeding period.     

Endemic avian toxoplasmosis on a farm in Illinois: clinical disease, diagnosis, biologic and genetic characteristics of Toxoplasma gondii isolates from chickens (Gallus domesticus), and a goose (Anser anser)

This study evaluated potential relationships between parasite egg/oocyst outputs in cow-calf beef herds located within the United States Northern Great Plains and herd longitude and latitude. Management of study herds was typical of herds from this region. Parasite egg/oocyst counts were measured from 10 cows and 5 calves selected from each herd near the end of the traditional grazing season (October 1993). The types and numbers of eggs and oocysts recovered from both cows and spring-born calves were consistent with those described in other studies. No significant relationship between fecal egg/oocyst counts and latitude was observed in calves or cows. Monezia egg output exhibited no significant correlation with longitude for calves or cows. In cows, a significant negative correlation was detected between coccidian oocyst counts and herd longitude but not between helminth egg counts and longitude. In calves, Nematodirus, trichostrongyle and Trichuris egg output and coccidian oocyst output were all negatively correlated with longitude. This negative correlation suggests that nematode populations within the study area decreased slightly from an east to west direction.     

Acquisition of immunity to Eimeria maxima in newly hatched chickens given 100 oocysts

The acquisition of immunity to Eimeria maxima by chicks infected 18 hr after hatch with a single dose of 100 oocysts was investigated. In the first experiment, birds were moved each day to clean cages in order to prevent the possibility of secondary infection resulting from ingestion of oocysts passed in their feces. Immunity was measured at 4 wk of age by calculation of oocyst production following challenge with 500 oocysts or weight gain following challenge with 100,000 oocysts. Large numbers of oocysts were produced by infected birds following challenge, although numbers were significantly less than those from birds that had been reared in the absence of infection (susceptible controls). The weight gain of infected birds following challenge was significantly greater than that of susceptible controls but less than that of unchallenged controls. Thus, only partial protection had been acquired, whether parasite replication or body weight gain was used to assess the extent of immunity development. In a second experiment, acquisition of immunity at 4 wk by chicks infected 18 hr after hatch with 100 oocysts of E. maxima and reared in floor pens in contact with their droppings was investigated. Infected birds produced no oocysts following challenge, and weight gains were not significantly different from the unchallenged controls, which indicates that full immunity had developed by 4 wk. It is concluded that if oocysts of Eimeria species are used to vaccinate day-old chicks, reinfection by oocysts present in the litter is necessary for the establishment of protective immunity.     

Coccidiosis causes diarrhea in calves in the pasture. Pasture coccidiosis caused by Eimeria alabamensis

A severe outbreak of diarrhoea in young (age 18-20 month) cattle 14 days after their first turnout is described. In the manure large numbers Eimeria alabamensis oocysts were found. This infection is considered as a case of coccidial diarrhoea in (older) calves at pasture.     

Endoparasites in calves of beef cattle herds: management systems dependent and genetic influences

Prevalences and intensities of excretion of faecal stages of Giardia duodenalis, Cryptosporidium parvum, Eimeria spp., Strongyloides papillosus and strongyles were determined in a German upland area in German Angus (GA) and German Simmental (GS) suckler of beef cattle herds covering two winter housing periods and the grazing season between them. Influences of the housing systems applied (maintenance on deep litter with (DL+) and without run-out (DL--), on slatted floor (SF) or by winter run-out yarding (WO)), breed differences and genetic influences by the sire were determined by statistical analyses; levels of IgG antibodies to E. bovis antigen were measured by ELISA. G. duodenalis was observed with a maximum prevalence of 38% in 4 weeks old calves, a cumulative incidence of 58% 9 weeks after birth and with generally low intensities. C. parvum infections were relatively rare with cumulative incidences of 20--25% in week 5 after birth. Highest prevalences were associated with housing system DL-- and a long-lasting calving period. Cumulative incidence of Eimeria spp. was almost 100%. E. bovis predominated by far followed by E. ellipsoidalis/zuernii. Mean maximum intensity of 1000 OpG occurred in week 7 after birth. Up to an age of the calves of 7 weeks >75% of all oocysts belonged to E. bovis. Prevalences and excretion intensities were lowest under the housing conditions SF and WO. Maternal antibodies in calves to E. bovis antigen were directly and inversely correlated with mean OpG values in GA and GS calves, respectively. S. papillosus was common with a cumulative incidence of 53% 9 weeks after birth and occurred independent of the housing system. Mean strongyle egg prevalence was 50% with 50--100 EpG by means throughout the grazing season. Egg excretion intensity in the early months of grazings was correlated with the age of the calves at turnout to pasture. Under the conditions of housing system DL-- GA calves could better control S. papillosus infections than GS calves whereas the latter were generally more effective in controlling the protozoa. Results of ANCOVA suggest significant paternal influences on S. papillosus infections in both breeds and on the protozoal infections in GA calves. The former could be disclosed independent of the housing system whereas environmental factors played an important role in the latter cases.     

Excretion of alcelaphine herpesvirus-1 by captive and free-living wildebeest (Connochaetes taurinus)

Excretion of alcelaphine herpesvirus-1 (AHV-1) is for all practical purposes limited to wildebeest calves under the age of 4 months. Sixty-one per cent of calves 1-2 months of age excreted virus with a mean titre of 9.8 X 10(4) cytopathic-forming foci/ml in their ocular fluid. The incidence declined sharply to less than 2% in wildebeest older than 6 months. No difference in age-related excretion of virus could be detected between free-living and captive wildebeest and no virus could be isolated from free-living pregnant wildebeest cows or from captive cows and their calves during the first 4 weeks after birth. The occurrence of wildebeest-derived malignant catarrhal fever (WD MCF) during spring, when wildebeest do not excrete virus, is a strong indication of the existence of an alternative host or an intermediate host capable of biological transfer of AHV-1.     

Long-term persistence of multi-drug-resistant Salmonella enterica serovar Newport in two dairy herds

OBJECTIVE: To evaluate the association between maintaining joint hospital and maternity pens and persistence of multi-drug-resistant (MDR) Salmonella enterica serovar Newport on 2 dairy farms. DESIGN: Observational study. SAMPLE POPULATION: Feces and environmental samples from 2 dairy herds. PROCEDURE: Herds were monitored for fecal shedding of S enterica Newport after outbreaks of clinical disease. Fecal and environmental samples were collected approximately monthly from pens housing sick cows and calving cows and from pens containing lactating cows. Cattle shedding the organism were tested serially on subsequent visits to determine carrier status. One farm was resampled after initiation of interventional procedures, including separation of hospital and maternity pens. Isolates were characterized via serotyping, determination of antimicrobial resistance phenotype, detection of the CMY-2 gene, and DNA fingerprinting. RESULTS: The prevalence (32.4% and 33.3% on farms A and B, respectively) of isolating Salmonella from samples from joint hospital-maternity pens was significantly higher than the prevalence in samples from pens housing preparturient cows (0.8%, both farms) and postparturient cows on Farm B (8.8%). Multi-drug-resistant Salmonella Newport was isolated in high numbers from bedding material, feed refusals, lagoon slurry, and milk filters. One cow excreted the organism for 190 days. Interventional procedures yielded significant reductions in the prevalences of isolating the organism from fecal and environmental samples. Most isolates were of the C2 serogroup and were resistant to third-generation cephalosporins. CONCLUSIONS AND CLINICAL RELEVANCE: Management practices may be effective at reducing the persistence of MDR Salmonella spp in dairy herds, thus mitigating animal and public health risk.     

Detection of rotavirus and coronavirus shedding in two beef cow herds in Idaho

Fecal samples were taken at the time of pregnancy examinations and at parturition from two beef herds. They were also taken from sick calves at the onset of disease, and from 25% of the healthy calves at 15 days of age. All fecal samples were examined by electron microscopy for viruses.

Four cows in herd A were detected excreting coronavirus, one at the time of the pregnancy examinations and three at parturition. The first cow was removed from the herd and the others calved at the end of the season. There were no sick calves.

No cows in herd B were detected excreting virus at the time of pregnancy checks, but fourteen coronavirus and two rotavirus carrier cows were found at parturition. All but two calves sampled had large numbers of virus particles in their feces. Clinical illness was associated with dams shedding virus and with nightly low temperatures.