An alkalinizing oral rehydration solution containing lecithin-coated citrus fiber is superior to a nonalkalinizing solution in treating 360 calves with naturally acquired diarrhea.

The aim of this field study was to compare the efficacy and cost of 2 commercially available oral rehydration therapy (ORT) solutions in treating dairy calves with naturally acquired diarrhea. A total of 1,349 newborn Holstein-Friesian calves were prospectively enrolled in the study. Calves were housed in individual hutches and fed a mixture of pasteurized hospital milk and an all-milk protein milk replacer twice per day. Calves were monitored twice each day from d 2 of life until 30 d of age for the presence or absence of diarrhea, and were assigned a fecal score and a hydration score at each examination. Calves that developed mild to severe diarrhea that did not need intravenous fluids and did not have clinical evidence of concurrent disease (n = 360) were assigned randomly to receive 1 of 2 commercial ORT solutions: a hypertonic alkalinizing ORT containing lecithin-coated citrus fibers (Diaque, group D, n = 180; Boehringer Ingelheim, Ingelheim, Germany), and an isotonic nonalkalinizing ORT (RE-SORB, group R, n = 180; Pfizer Animal Health, New York, NY) for 2 to 8d; the duration of treatment depended on whether diarrhea was still present. No significant differences were observed in mortality rates or treatment failure rates between the 2 treatment groups. Fecal consistency returned to normal more quickly in group D calves than in group R calves; consequently, group D calves were treated for 1d less than were group R calves. The increase in body weight after 4d of treatment was larger in group D than in group R. The average daily gain from birth to weaning in calves that did not develop concurrent disease (such as pneumonia) during the study period tended to be higher in group D calves (0.53±0.11 kg/d) than in group R calves (0.51±0.09 kg/d). The smaller number of treatments at a lower cost per treatment produced a cost advantage of $4.82 per treated calf in group D calves compared with group R calves. Our findings support the concept that milk should continue to be fed to diarrheic calves that are being administered an ORT solution in order to maintain growth.

Detection of multiple Mycoplasma species in bulk tank milk samples using real-time PCR and conventional culture and comparison of test sensitivities.

The objective of this study was to further validate a SYBR PCR protocol for Mycoplasma spp. by comparing it with standard microbial culture in the detection of Mycoplasma spp. in bulk tank milk samples. Additionally, we identified Mycoplasma spp. present by analysis of PCR-generated amplicons [dissociation (melt) temperature (T(m)), length, and DNA sequence]. The research presented herein tests the hypothesis that the SYBR PCR protocol is as sensitive as conventional culture for the detection of Mycoplasma spp. in bulk tank milk samples. Mycoplasmas cause several important disease syndromes in cattle, including mastitis in dairy cows. The standard diagnostic method at the herd level has been microbial isolation of mycoplasmas on 1 of several specialized media and speciation through biochemical or immunological techniques; repeated sampling schemes are recommended. The development of a real-time SYBR PCR protocol offers advantages in decrease of time to detection, cost, and complexity. The T(m) of the double-stranded DNA generated from the PCR reaction was used to detect the presence of and tentatively identify the species of mycoplasmas other than Mycoplasma bovis. In the SYBR PCR protocol, the presence of multiple species of mycoplasmas is indicated by an atypical dissociation curve. Gel electrophoresis and sequencing of the amplicons was used to confirm the mycoplasma species present when a non-M. bovis organism was detected (T(m) not equal to M. bovis) and used to identify all the mycoplasma species present for the samples with atypical dissociation curves. Mycoplasma bovis was identified in 83% of SYBR PCR mycoplasma-positive bulk tank samples. Another mycoplasma was identified either alone or in addition to M. bovis in 25% of SYBR PCR mycoplasma-positive bulk tank milk samples. Four species of mycoplasma other than M. bovis (Mycoplasma alkalescens, Mycoplasma arginini, Mycoplasma bovigenitalium, and Mycoplasma gateae) were identified in bulk tank milk samples tested with this method. Five farms had 2 mycoplasma species occurring at different times in their bulk tanks. Two mycoplasma species were identified in the same bulk tank sample in 7 instances on 2 farms. The finding of multiple Mycoplasma spp. coexisting on a farm and even in the same bulk tank milk sample indicates that the clinical significance of multiple mycoplasma species in the pathology of intramammary infections should be investigated further. In comparison with conventional culture, the SYBR PCR protocol was slightly (but not statistically significantly) more sensitive in the detection of mycoplasmas in bulk tank milk.

Risk of Mycoplasma bovis transmission from contaminated sand bedding to naive dairy calves.

The objective of this study was to evaluate the possible transmission of Mycoplasma bovis from positive sand bedding to naïve dairy calves. Twelve preweaned Holstein bull calves were blocked in pairs and randomly assigned as unexposed controls (n=6) bedded with control sand, or exposed calves (n=6) bedded with sand previously positive for M. bovis at a dairy farm. Bedding sand was cultured weekly. Nasal and ear swabs and sera were collected weekly, tracheal swabs were collected monthly, and by the end of the 105-d study, all calves were euthanized (n=10) or died (n=2). Sera were tested for M. bovis-specific antibody. Mycoplasma spp. culture was performed on nasal and ear swabs; culture and a PCR differentiating multiple Mycoplasma spp. were performed on postmortem samples of lung, retropharyngeal lymph node, and trachea from each calf. A complete necropsy also was performed. During 6 wk, mycoplasma concentration in exposed group sand was between 200 and 32,000 cfu/g. All 166 tracheal swabs, nasal and ear swabs, and postmortem tests from all calves were negative for mycoplasma. All 94 sera were negative for M. bovis-specific antibody. No gross pathology suggestive of mycoplasma disease was detected. The probability of mycoplasma detection, if an exposed calf had become infected 4 wk after exposure, ranged between 97 and 99% depending on time of exposure for individual calves. There was no evidence that sand bedding contaminated with M. bovis might serve as a source of transmission to naïve dairy calves.

Survival and replication of Mycoplasma species in recycled bedding sand and association with mastitis on dairy farms in Utah.

Mycoplasma spp., usually Mycoplasma bovis, are important bovine pathogens that can cause mastitis, metritis, pneumonia, and arthritis. The currently documented routes of transmission of Mycoplasma spp. are through contaminated milking equipment and by direct animal contact. The existence of environmental sources for Mycoplasma spp. and their role in transmission and clinical disease is poorly characterized. Mycoplasma spp. (confirmed as M. bovis in 2 of 4 samples tested using PCR) was found in recycled bedding sand originating from a dairy experiencing an outbreak of clinical mycoplasma mastitis. Mycoplasma spp. were subsequently found in bedding sand from 2 other dairies whose bulk-tank milk was mycoplasma-positive. The association between the occurrence of Mycoplasma spp. in recycled bedding sand and mycoplasma mastitis in cows was further investigated using a pile of recycled sand from dairy 1. Study objectives included the determination of factors associated with the concentration of Mycoplasma spp. in recycled bedding sand and the duration of survival of mycoplasmas in the sand. We also evaluated the efficacy of 2 disinfectants at 2 different concentrations each for the elimination of Mycoplasma spp. from contaminated sand. Mycoplasma spp. survived in the sand pile for 8 mo. The concentration of Mycoplasma spp. within the sand pile was directly related to temperature and precipitation. It was also positively associated with the growth of gram-negative microorganisms, suggesting the possibility of the formation of a biofilm. Ideal temperatures for replication of Mycoplasma spp. occurred between 15 and 20 degrees C. Moisture in the sand and movement of the sand pile also appeared to play a role in replication of mycoplasmas. We found that 0.5% sodium hypochlorite or 2% chlorhexidine were efficacious in eliminating Mycoplasma spp. from contaminated bedding sand. Recycled bedding sand could be an environmental source of Mycoplasma spp., including M. bovis, infections in dairy cows. Future studies should investigate the contribution of this environmental source to the epidemiology of mycoplasma infections in dairy cattle.

Bacteremia associated with naturally occuring acute coliform mastitis in dairy cows.

OBJECTIVE: To determine the incidence of bacteremia in dairy cows with naturally occurring acute coliform mastitis (ACM) with a wide range of disease severity. DESIGN: Cohort study. ANIMALS: 144 dairy cows with ACM from 6 herds. PROCEDURE: Cows were examined at time of identification of ACM (time 0) and classified as having mild, moderate, or severe mastitis on the basis of rectal temperature, hydration status, rumen contraction rate, and attitude. Cows were reexamined at 24 or 48 hours. Bacteriologic culturing of milk and blood (30 ml), CBC, and serum biochemical analysis were performed at each time point. Appropriate samples were obtained at a single point from herdmates without mastitis (controls) that were closely matched for lactation number and days since parturition. Blood culture results were compared among severity groups and controls by use of chi2 tests, as was outcome of an ACM episode for cows grouped by blood bacterial isolates. RESULTS: Bacteria were isolated from 52 blood samples from 46 of 144 (32%) cows with ACM, which was significantly more than control cows (11/156; 7.1%). Group-1 isolates (Escherichia coli, Pasteurella multocida, Mannheimia haemolytica, Klebsiella pneumoniae, Enterobacter agglomerans, and Salmonella enterica serotype Typhimurium) were identified in 20 of 144 (14%) cows with ACM and 0 of 156 control cows. Group-1 isolates were identified in 4.3, 9.1, and 42% of cows classified as having mild, moderate, and severe ACM, respectively. Escherichia coli and K pneumoniae milk and blood isolates obtained from the same cow were of the same genotype. Bacillus spp were identified in 21 of 144 (15%) cows with ACM, which was significantly more than control cows (3/156; 1.9%). Thirty-five percent of cows with a group-1 isolate died during the mastitis episode. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that bacteremia develops in a substantial proportion of cows with ACM. Classification of severity of disease is important for establishment of effective treatment protocols; parenteral antimicrobial treatment may be indicated in cows with ACM.

Environmental gram-positive mastitis treatment: in vitro sensitivity and bacteriologic cure.

A clinical trial was conducted in a large dairy herd to determine the efficacy of intramammary pirlimycin hydrochloride administration during lactation for bacteriologic clearance of gram-positive environmental clinical and subclinical mastitis infections. Quarters infected with environmental streptococci that received pirlimycin therapy (13/28) were 1.8 times more likely to resolve infection than untreated quarters (5/14). The small numbers of quarters infected with coagulase-negative staphylococci resulted in inadequate power to assess treatment differences in cure rate. Although the association was not statistically significant, quarters from cows with sensitive environmental streptococci isolates from composite samples (8/13) resolved infection with treatment at approximately twice the rate of treated quarters with resistant isolates (3/10).

Comparison of a controlled injection pressure system with a conventional technique.

OBJECTIVE: The purpose of this study was to compare a device that controls flow rate during injection through use of a foot pedal with a conventional atraumatic syringe injection technique. We determined the change from preinjection to postinjection anxiety, the pain perception, procedure tolerance, and anxiety about future injections. STUDY DESIGN: Dental injection anxiety questionnaires were completed by 80 endodontic patients immediately before and after administration of local anesthetic with the 2 experimental methods. Patients also completed visual analog scales to rate their pain perception during injection, their rating of the overall experience, and their anticipated anxiety about a future dental injection. RESULTS: Patients experienced significantly lower overall postinjection anxiety and pain of injection and had significantly more positive overall experience ratings with the conventional technique than with the controlled-rate procedure. CONCLUSIONS: A conventional atraumatic syringe injection technique was superior to a controlled injection pressure system in pain perception and procedure tolerance and in reducing postinjection dental anxiety.

Linear dye penetration of a calcium phosphate cement apical barrier.

Linear dye penetration was evaluated in teeth with open apices in which calcium phosphate cement was used as an apical barrier to facilitate obturation. The apical foramens of 42 extracted single-rooted human teeth were opened to a size 90 file. Half the teeth received apical barriers consisting of calcium phosphate cement (CPC) followed by obturation using a customized gutta-percha cone/ lateral condensation technique. The other half were obturated without benefit of apical barriers. Linear dye penetration was measured after 48 h exposure to India ink. The teeth receiving apical CPC barriers before obturation had significantly less dye penetration than teeth without apical barriers. Based on its proven biocompatibility and osteconductive potential, calcium phosphate cement may serve well as a replacement for calcium hydroxide in a single-visit immediate apical barrier apexification technique.