Clinical Evaluation of All Ceramic Zirconia Framework Resin Bonded Bridges.

OBJECTIVE: To evaluate the clinical longevity of 58 adhesively bonded single unit yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic Resin Bonded Bridges (RBB). MATERIALS AND METHODS: Twenty six consecutive patients with at least one congenitally missing tooth in the maxilla or mandible were provided with 58 single unit Y-TZP RBBs. The cantilever RBBs were designed and milled using a CAD-CAM system to produce frameworks which were veneered using a glass-ceramic material and cemented with a self-etching dual-cure resin cement. RESULTS: Following a mean follow up period of 36.2 months (maximum 62.3 months, minimum 25.4 months), 48 restorations remain in service with a survival rate of 82.7%. One anterior retainer fracture was encountered and no fractures of the posterior framework or ceramic were noted within the time frame reported. CONCLUSIONS: All ceramic Y-TZP RBBs replacing maxillary and mandibular teeth in the anterior and posterior areas demonstrated an 82.7% Kaplan Meier survival rate over 3 years, which was comparable to previously published survival rates for the non-perforated metal framework RBBs. CLINICAL IMPLICATIONS: Replacement of anterior or posterior teeth using single unit cantilevered RBBs using Y-TZP ceramics should be considered a viable restorative option with a high survival rate.

Crystallization of high-strength nano-scale leucite glass-ceramics.

OBJECTIVES: Fine-grained, high strength, translucent leucite dental glass-ceramics are synthesized via controlled crystallization of finely milled glass powders. The objectives of this study were to utilize high speed planetary milling of an aluminosilicate glass for controlled surface crystallization of nano-scale leucite glass-ceramics and to test the biaxial flexural strength. METHODS: An aluminosilicate glass was synthesized, attritor or planetary milled and heat-treated. Glasses and glass-ceramics were characterized using particle size analysis, X-ray diffraction and scanning electron microscopy. Experimental (fine and nanoscale) and commercial (Ceramco-3, IPS Empress Esthetic) leucite glass-ceramics were tested using the biaxial flexural strength (BFS) test. Gaussian and Weibull statistics were applied. RESULTS: Experimental planetary milled glass-ceramics showed an increased leucite crystal number and nano-scale median crystal sizes (0.048-0.055 µm(2)) as a result of glass particle size reduction and heat treatments. Experimental materials had significantly (p<0.05) higher mean BFS and characteristic strength values than the commercial materials. Attritor milled and planetary milled (2h) materials showed no significant (p>0.05) strength difference. All other groups' mean BFS and characteristic strengths were found to be significantly different (p<0.05) to each other. The mean (SD) MPa strengths measured were: Attritor milled: 252.4 (38.7), Planetary milled: 225.4 (41.8) [4h milling] 255.0 (35.0) [2h milling], Ceramco-3: 75.7 (6.8) and IPS Empress: 165.5 (30.6). SIGNIFICANCE: Planetary milling enabled synthesis of nano-scale leucite glass-ceramics with high flexural strength. These materials may help to reduce problems associated with brittle fracture of all-ceramic restorations and give reduced enamel wear.

Crystallization of high-strength fine-sized leucite glass-ceramics.

Manufacturing of leucite glass-ceramics often leads to materials with inhomogeneous microstructures. Crystal-glass thermal mismatches which produce microcracking around larger crystals-agglomerates are associated with reduced mechanical properties. The hypotheses were that fine (< 1 µm) crystal size and uniform microstructure in a thermally matched glass would increase the biaxial flexural strength (BFS). Glass was synthesized, attritor-milled, and heat-treated. Glasses and glass-ceramics were characterized by XRD, SEM, and Dilatometry. Experimental (A, M1A and M2A) and commercial glass-ceramics were tested by the BFS test. Experimental glass-ceramics showed an increased leucite crystal number and decreased crystal size with glass particle size reduction. Leucite glass-ceramics (< 1 µm) showed minimal matrix microcracking and BFS values of [mean (SD) MPa]: M1A = 253.8 (53.3); and M2A = 219.5 (54.1). Glass-ceramics M1A and M2A had higher mean BFS and characteristic strength than the IPS Empress Esthetic glass-ceramic (p < 0.05). Fine-grained, translucent leucite glass-ceramics were synthesized and produced high mean BFS.

Effect of the introduction of a lumbar-puncture sticker and teaching manikin on junior staff documentation and performance of paediatric lumbar punctures.

BACKGROUND: Performing a lumbar puncture in an unwell child can cause anxiety in both the parent and the junior doctor. There is increasing evidence of post-lumbar-puncture complications in this age group. AIMS: To improve the documentation, consent for and technical performance of paediatric lumbar punctures to 100% of the required standard within 3 months. SETTING: The paediatric emergency department of a the Royal North Shore Hospital (University of Sydney, Sydney, Australia). PARTICIPANTS: Paediatric emergency staff, including residents, registrars and consultants. METHODS: Medical records of 40 consecutive children who had undergone a lumbar puncture in the 6 months before the introduction of the lumbar-puncture proforma were reviewed. After introduction of the proforma, the records of 25 consecutive patients were reviewed to assess changes in the outcome measures. Before introduction of the proforma, junior medical staff were instructed in the procedure using specialised lumbar puncture manikins (Baby Stap; Laerdel, USA). RESULTS: Before introduction of the proforma, the median number of documented indicators was 4, out of a maximum of 12. There was almost no documentation of parental consent, patient complications and analgesia. Introduction of the proforma resulted in a highly marked increase to a median of 12 documented indicators per patient (p<0.01, 95% confidence interval 6 to 8). CONCLUSIONS: The introduction of a lumbar-puncture proforma and formal teaching sessions using a paediatric manikin led to a marked improvement in the documentation of paediatric lumbar-punctures. Lumbar-punctures can be performed only by accredited medical officers who have achieved competency on the lumbar-puncture teaching manikin.

The effect of veneering and heat treatment on the flexural strength of Empress 2 ceramics.

OBJECTIVES: The aims of the study were to test and compare the biaxial flexural strength and reliability of Empress 2 ceramics after heat treatment and the addition of the veneering material and to characterise their microstructures. METHODS: Forty disc specimens (2 x 14 mm) and forty disc specimens (1 x 14 mm) were produced by heat pressing in the EP 500 press furnace. Group 1 (2 x 14 mm Empress 2 core) was as heat pressed and group 2 (2 x 14 mm Empress 2 core) was subjected to the recommended firing cycles. Groups 3 and 4 (1 x 14 mm Empress 2 core) were veneered with the dentine material and heat-treated as per group 2. Groups 1, 2 and 3 were lapped to 800 grit silicon carbide paper on the compressive surface only and group 4 on both the compressive and tensile test surfaces. Twenty disc specimens per group were tested using the biaxial flexure test at a crosshead speed of 0.15 mm/min. Specimens were characterised using X-ray diffraction (XRD) and secondary electron imaging (SEM). RESULTS: Mean biaxial flexural strengths (MPa+/-SD) were group 1: 265.5+/-25.7; group 2: 251.3+/-30.2; group 3: 258.6+/-21.4 and group 4: 308.6+/-37.7. There was no statistical difference between groups 1, 2 and 3 (p>0.05), but differences for group 4 (p<0.05). XRD and SEM revealed lithium disilicate and lithium orthophosphate in the Empress 2 core material and an amorphous glass and some evidence of a crystalline phase in the dentine material. CONCLUSIONS; Veneering or heat treatment of Empress 2 ceramics did not significantly affect the mean biaxial flexural strength (p>0.05) or reliability. Surface modification of the Empress 2 core material increased the mean biaxial flexural strength (p<0.05).

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).

Flexural strength optimisation of a leucite reinforced glass ceramic.

OBJECTIVES: The aims of the study were to process a ceramic material with a fine leucite particle size using hot pressing techniques, to increase the flexural strength, reliability and ease of use. METHODS: A starting glass composition of wt%; 64.2% SiO(2), 16.1% Al(2)O(3), 10.9% K(2)O, 4.3% Na(2)O, 1.7% CaO, 0.5% LiO and 0.4% TiO(2) was used to produce a leucite reinforced ceramic material. Twenty-one porcelain discs were produced by sintering the ceramic frit (group 1) and sixty-three discs by heat pressing the frit (groups 2, 3 and 4). Twenty-one Empress 1 ceramic discs were also heat pressed (group 5). Disc specimens were tested using the biaxial flexure test at a crosshead speed of 0.15mm/min and the data analysed using the Scheffé F multiple comparison test and Weibull statistics. Specimens were characterised using X-ray diffraction (XRD), secondary electron imaging and energy dispersive X-ray analysis where applicable. RESULTS: The heat pressed groups (2, 3 and 4) had higher mean biaxial flexural strengths and characteristic strength values than groups 1 and 5 (p<0.05). XRD revealed the presence of tetragonal leucite in all test groups. Fine leucite crystals, tabular platelets and minimal matrix microcracking were found in the microstructure of test groups (1-4) with a more uniform leucite distribution in the heat pressed specimen groups (2, 3 and 4), which were associated with a significant increase in the biaxial flexural strength and reliability. SIGNIFICANCE: Optimisation of the microstructure by producing a fine microstructure and controlling the distribution via the correct pressing parameters may be extremely advantageous in these systems.

Effect of dietary IgG source (colostrum, serum, or milk-derived supplement) on the efficiency of Ig absorption in newborn Holstein calves.

This study was designed to compare the absorptive efficiency of IgG from a commercial bovine serum product (bovine serum), cow colostrum (positive control), and two commercial milk-derived IgG supplements (supplement 1 and supplement 2). Newborn Holstein calves, collected at birth and prior to the consumption of colostrum, were allotted to treatment by alternating birth order. Colostrum supplement treatments were fed according to manufacturer's recommendations at birth and again at 12 h. This strategy resulted in varying masses of total IgG being offered to the calves (200, 90, 50, and 60 g of IgG for colostrum, bovine serum, supplement 1, and supplement 2, respectively). Blood samples were collected at 0, 12, and 24 h after the end of treatment administration. Plasma volume was estimated as 9.10% of birth weight. Apparent efficiency of IgG absorption at 24 h was determined. Plasma IgG concentrations at 24 h differed for each treatment (12.1, 6.8, 2.2, and 3.5 g of IgG/L for colostrum, bovine serum, supplement 1, and supplement 2, respectively). Apparent efficiency of IgG absorption was greatest for bovine serum compared with colostrum and supplement 1. No treatment differences were detected on the occurrence of mortality. However, calves fed bovine serum tended to have fewer treatments for illness compared with calves fed colostrum and supplement 1. Calves receiving bovine serum-derived IgG had improved IgG absorption efficiency and a tendency toward fewer medical treatments compared with calves consuming colostrum or a dried colostrum product.

Passive immunoglobin transfer in newborn calves fed colostrum or spray-dried serum protein alone or as a supplement to colostrum of varying quality.

Two experiments were conducted to investigate the effect of serum-derived immunoglobin (Ig) source and the effect of colostrum supplementation with serum-derived Ig on the attainment of passive immunity in newborn colostrum-deprived calves. In experiment 1, colostrum-deprived Holstein bull calves were fed pooled colostrum (PC, n = 9), spray-dried bovine serum (BS, n = 11), or spray- dried porcine serum (PS, n = 9). All treatments were balanced to provide 45 g of IgG in a 2-L volume at birth and again 12 h later. Calves receiving BS had higher 24-h serum IgG concentrations than did calves receiving PC or PS (8.3, 5.7, and 4.2 g of IgG/L for BS, PC, and PS, respectively). In experiment 2, the effect of supplementing bovine colostrum of varying quality with BS on Ig absorption was assessed. Thirty-two colostrum-deprived Holstein bull calves and four freemartin heifer calves were allotted by birth order to receive one of three treatments. Treatments consisted of 1) 2 L of pooled high quality colostrum (95.8 g of IgG, 0% from BS), 2) 2 L of pooled medium quality colostrum mixed with BS (95.2 g of IgG, 47% from BS), or 3) 2 L of low quality colostrum mixed with BS (98.8 g of IgG, 70% from BS). Serum IgG concentrations at 24 h after treatment were greater for calves receiving medium and low quality colostrum supplemented with BS (6.2, 9.6, and 9.6 g of IgG/L for high, medium, and low quality colostrum, respectively). Similarly, apparent efficiency of IgG absorption was greater for calves receiving medium and low quality colostrum supplemented with BS (25, 37, and 38% for high, medium, and low quality colostrum, respectively). The results of these studies suggest that dried BS contains a concentrated source of Ig, which is efficiently absorbed by newborn calves. Supplementation of marginal or low quality colostrum with dried BS is an effective means of improving passive transfer of IgG in newborn calves.

The biaxial flexural strength of two pressable ceramic systems.

The biaxial flexural strength of Optimal pressable ceramics and IPS Empress pressable ceramics were tested, compared and the micro-structures and compositions explored. The materials evaluated were Optimal shaded (Opcs) and unshaded (Opcus) ceramics and IPS Empress shaded (Ems) and unshaded (Emus) ceramics. Twenty-one disc specimens per material were prepared, heat-treated and tested. The piston on three-ball test ASTM F394-78 (1991) was used to test the specimens in a universal testing machine at a crosshead speed of 0.15 mm/min. Specimens were viewed in a scanning electron microscope and X-ray diffraction used to determine the phases present. Mean strengths (MPa +/- SD) were: Ems 120.1 +/- 20.5, Emus 135.8 +/- 16.0, Opcs 139.1 +/- 14.3 and Opcus 138.0 +/- 11.5. There was no statistically significant difference between Optimal shaded, Optimal unshaded and Empress unshaded strength values (p > 0.05). Empress shaded strength values were significantly lower than the other materials tested (p < 0.05). Weibull analysis provided m values: Ems 6.1, Emus 10.2, Opcs 12.8 and Opcus 13.9 and 1% and 5% probabilities of failure. Secondary electron imaging revealed a dense dispersal of leucite crystals in the glassy matrix of the Optimal ceramics of an average size 5.5 +/- 9.7 micron 2 for the Optimal shaded ceramic and 6.6 +/- 13.3 micron 2 for the Optimal unshaded ceramic. Leucite crystal agglomerates were evident for the Empress shaded material and a uniform distribution of fine leucite crystals (1.9 +/- 1.8 micron 2) for the Empress unshaded ceramic. Crystal and matrix microcracking were present in most of the material microstructures, together with porosity and tabular alumina platelets in the Optimal ceramics. X-ray diffraction revealed the presence of tetragonal leucite and small amounts of cubic leucite. Optimal ceramics and Empress unshaded ceramic provided higher strength and Weibull m values compared with Empress shaded ceramic. Inherent material defects were characterised and cubic leucite was identified.

Investigation of the dry and wet fatigue properties of three all-ceramic crown systems.

PURPOSE: The aim of this study was to investigate the influence of fatigue on the fracture strength of In-Ceram (Vita Zahnfabrik), Optimal Pressable Ceramic (Opc, Jeneric Pentron), and IPS Empress (Ivoclar-Vivadent) in both wet and dry environments. MATERIALS AND METHODS: Twenty-six crown shapes measuring 8.0 mm in diameter and 8.5 mm in height were fabricated for each ceramic system. For each ceramic system, 10 specimens were tested for fracture strength without fatiguing. A second group (8 specimens) was submitted to a fatigue and fracture test in dry conditions, and a third group (8 specimens) was fatigued and fractured in a wet environment using a mechanical testing machine (Instron). The results were statistically analyzed using a Mann-Whitney test. RESULTS: The results indicated that: (1) The facture strength for In-Ceram was significantly stronger than IPS Empress. No difference was found between In-Ceram and Opc, and Opc and IPS Empress. (2) The strength of the three ceramic systems decreased significantly after fatiguing in both dry and wet environments compared with the nonfatigued specimens. No difference was found between fatiguing in dry and wet environments. (3) For the three systems fatigued in a dry environment and then fracture tested, In-Ceram and Opc were significantly stronger than IPS Empress, but no difference was found between the three systems fatigued in a wet environment. CONCLUSION: Significant differences in the fracture strengths of the different systems investigated may be seen that result from both the nature of the system and the environment in which the specimens were fatigued.

Fracture strength of all-ceramic crowns.

This paper compares the fracture strength of three types of all-ceramic crown shape systems (In ceram, OPC and IPS Empress) cemented with either a commercial resin cement, zinc phosphate or glass ionomer. Twenty test crown shapes with 8 mm diameter and 8.5 mm height were fabricated for each type of ceramic. Ten In ceram crown shapes were luted on the die using zinc phosphate, while ten OPCTM and IPS Empress were luted using resin cement specified for the particular system. Another ten specimens each, of In ceram, OPC and IPS Empress, were luted on the die using a glass ionomer. The crown shapes were fractured in a mechanical testing machine (Instron) using a steel ball, 4 mm diameter, that contacted the occlusal surface and the resulting data were statistically analysed using a Mann-Whitney test. The results showed that: (1) In ceram crown shapes luted with zinc phosphate were significantly stronger than IPS Empress crown shapes luted with resin cement (p < 0.05), but no difference was observed compared with OPC crown shapes luted with resin cement. No statistical difference was found between OPC and IPS Empress crown shapes. (2) When the three ceramics were luted with glass ionomer, the In ceram was significantly stronger than OPC (p < 0.05) and IPS Empress (p < 0.05). OPC was significantly stronger than IPS Empress (p < 0.05).

Comparison of the wet and dry fatigue properties of all ceramic crowns.

The purpose of this paper was to investigate the influence of fatigue on the fracture strength of In ceram, optimal pressable ceramic (OPCTM) and IPS Empress in both wet and dry environments. Twenty-six crown shapes 8 mm in diameter and 8.5 mm in height were fabricated for each ceramic system. For each ceramic system, ten specimens were tested for fracture strength without fatiguing. The second group was submitted to a fatigue and fracture test in a dry (eight specimens) and a third group in a wet (eight specimens) environment using an Instron testing machine. The results were statistically analysed using a Mann-Whitney test. The results indicated that: (i) the fracture strength for In ceram was significantly stronger than OPCTM and IPS Empress (p<0.05) - no difference was found between OPCTM and IPS Empress; (ii) fatiguing and fracture testing showed a significant decrease in the fracture strength for In ceram and IPS Empress in the wet environment and no difference was found in the dry environment - no difference was found for OPCTM; and (iii) when fatigued in a dry environment, In ceram crown shapes were significantly stronger than OPCTM and IPS Empress (p<0.05) - the same statistical differences were found when fatigued in a wet environment.

The transverse strength, reliability and microstructural features of four dental ceramics--Part I.

OBJECTIVES: The flexural strength, reliability and microstructure of a heat pressed ceramic system (Empress) was evaluated in comparison with three current frit materials used in ceramic crown and inlay construction. METHODS: Twenty bar specimens per material were constructed, overglazed and transverse tested at a crosshead speed of 0.5 mm/min. Etched and fractured bar specimens were viewed under a scanning electron microscope using secondary electron imaging. RESULTS: Mean strengths (MPa +/- SD) were: Empress, 117.3 +/- 31.7; Cerinate porcelain, 118.2 +/- 8.7; Corum porcetain, 92.9 +/- 13.3; and Alpha porcelain, 60.9 +/- 10.1. Results were highly significant (P < 0.001) with differences between all groups (P < 0.05) except Cerinate porcelain and Empress (P > 0.05). Weibull analysis of the results provided m-values and the predicted strength at the 1 and 5% probabilities of failure. Microstructural examination using secondary electron imaging showed leucite crystals 1.6-3.5 microns and associated microcracking in Corum porcelain and leucite crystal clusters (1.5 microns) in Empress. Cerinate porcelain exhibited a uniform distribution of fine leucite crystals (1 micron). Spherical porosity combined with crack pore combinations were noted in Vita Alpha porcelain. CONCLUSIONS: Empress glass ceramic was not stronger than Cerinate or more reliable than many of the frit materials. Uniform leucite distribution and fine crystal size may be associated with improved strength and reliability.

The biaxial flexural strength and reliability of four dental ceramics--Part II.

OBJECTIVES: The biaxial flexural strength and reliability of four dental ceramics including: Empress glass ceramic (EM), Cerinate porcelain (CE), Corum porcelain (CO) and Alpha porcelain (AL) were compared. METHODS: Twenty disc specimens per material were prepared overglazed and tested. The piston on three ball test was used to test the specimens in a universal testing machine at a crosshead speed of 0.15 mm/min. Weibull analysis provided m-values and the 1 and 5% probabilities of failure. RESULTS: Mean strengths (MPa +/- SD) were: EM, 133.5 +/- 21.5; CE, 109.1 +/- 11.3; CO, 119.8 +/- 19.2; and AL, 68.2 +/- 9.9. There was no statistical difference between EM or CO and CO and CE strengths (P > 0.05). Weibull m-values included: EM, 6.60; CE, 10.20; CO, 5.27; and AL, 6.93. Cerinate had the highest m-value (P < 0.01) and good dependability. CONCLUSION: Empress was not stronger or more reliable than many of the frit materials.

Oxytetracycline residues in milk after intrauterine treatment of cows with retained fetal membranes.

OBJECTIVE: To establish the maximum concentration and duration of oxytetracycline residues in milk from cows with retained fetal membranes given the antimicrobial via intrauterine infusion, and to investigate whether the number of infusions or the presence of fever (> 39.7 C) affected the duration of residues. DESIGN: Prospective study. ANIMALS: 54 Holstein cows with retained fetal membranes on a single 1,400-cow commercial dairy. PROCEDURE: Cows were treated once a day with 5 g of oxytetracycline (50 ml of 100 mg/ml solution in a povidone base) by intrauterine infusion for at least 2 days, or until the membranes were expelled. Cows that became febrile (rectal temperature > or = 39.7 C) were also given 20,000 IU of procaine penicillin G/kg of body weight, i.m., for 2 to 4 days. Milk samples were collected at 24-hour intervals during treatment. and at 12-hour intervals after the last treatment. All samples were frozen and submitted every 2 weeks for high performance liquid chromatography analysis for oxytetracycline. RESULTS: Oxytetracycline was detected in milk of all cows during treatment, at a maximum concentration ranging from 47.2 to 1,804.6 micrograms/kg (mean, 316.9 micrograms/kg). Duration of oxytetracycline residues after the last infusion ranged from 0 to 144 hours (mean, 52.3 hours). Neither the number of infusions received, nor development of rectal temperature > 39.7 C, affected the maximum concentration or the duration of oxytetracycline residues in milk. CLINICAL IMPLICATIONS: Milk obtained from cows that had been treated for retained fetal membranes by intrauterine infusion of oxytetracycline should be discarded to avoid illegal residues.

Age-related changes in amounts and concentrations of collagen and elastin in normotensive human thoracic aorta.

Twenty thoracic aortas were obtained post-mortem from subjects between the ages of 14 and 90 years who had previously been recorded as normotensive. Full wall thickness samples of 1 cm diameter were taken at six sites between heart valve and diaphragm. Lipid-free dry weight (mg per sample) and amounts (mg per sample) and concentrations (mg/mg dry weight) of collagen and elastin were determined. Lipid-free dry weight and amount of collagen showed highly significant decreases with age (P < 0.0001), with the amount of elastin less so (P = 0.003), representing losses of 92%, 80% and 62%, respectively, between the ages of 14 and 90 years. In contrast, the concentrations of both collagen and elastin increased significantly with age (P < or = 0.0002) by 72% and 140%, respectively, over the age range studied. However, in both cases, the increase occurred substantially after the age of 45. Therefore, besides demonstrating loss of collagen and elastin from the aortic wall with age, these results suggest strongly that there is a parallel loss of other aortic components at a rate which outstrips that of either collagen or elastin in later life.

Evaluation of the use of intrauterine infusions of oxytetracycline, subcutaneous injections of fenprostalene, or a combination of both, for the treatment of retained fetal membranes in dairy cows.

Dairy cows (n = 207) that had retained fetal membranes for more than 8 hours after parturition were randomly assigned to 1 of 4 treatment groups (group 1, daily intrauterine infusion of oxytetracycline; group 2, daily intrauterine infusion of oxytetracycline and a single SC injection of fenprostalene; group 3, a single SC injection of fenprostalene; and group 4, untreated controls). Cows were monitored daily. Subsequent disease conditions were recorded, and appropriate treatments were initiated. Interval from parturition to expulsion of fetal membranes was unaffected by treatment regimen. The frequency of cows with high rectal temperatures (> or = 39.5 C) was significantly (P < 0.05) less in cows treated with oxytetracycline infusions; however, the frequency of displaced abomasum, ketosis, and mastitis was unaffected by treatment method. Treatment method appeared to influence the development of postpartum uterine pathologic conditions. Treatment with oxytetracycline and fenprostalene (group 2) increased (P < 0.05) the frequency of pyometra. Treatment with fenprostalene (groups 2 and 3) decreased the number of cows with a palpable uterine lumen detectable during per rectal palpation at 28 to 42 days after parturition. Reproductive efficiency, as determined on the basis of the interval from parturition to conception, was unaffected by treatment protocol.

Efficacy of a Propionibacterium acnes immunostimulant for treatment of chronic Staphylococcus aureus mastitis.

This study determined the efficacy of treatment of chronic Staphylococcus aureus IMI of lactating dairy cows with a biological response modifier consisting of a killed preparation of Propionibacterium acnes. Fifty-one lactating dairy cows with chronic S. aureus IMI on two commercial dairies were enrolled in a controlled, randomized field trial. Twenty-four cows received 1 ml of the immunostimulant twice weekly for 4 wk, and the remainder of the cows served as untreated controls. Quarter milk samples were collected for SCC from all cows at 3 and 6 wk after initiation of treatment and for culture at 6 wk after initiation of treatment. If samples were negative for S. aureus at 6 wk, cows were sampled again for culture 1 wk later for 2 successive d before being considered cured. For the cows treated with immunostimulant, 16.7% (36.7% of infected quarters) were cured of S. aureus IMI; for the untreated group, 11.1% of cows (32.2% of quarters) were cured. The difference was not statistically significant. Immunostimulant treatment had no effect on quarter SCC in infected quarters overall, but, in those quarters that were cured of S. aureus infection, quarter SCC of treated cows tended to be lower than SCC of control cows.