Three laparoscopic procedures were performed on each of 6 adult jersey cows in the first trimester of gestation to describe normal laparoscopic anatomy of the bovine abdomen. Also, a technique for laparoscopy of the cranioventral portion of the abdomen was described. Right paralumbar fossa, left paralumbar fossa, and cranioventral midline laparoscopy were performed 72 hours apart on each cow. Physical examination findings, CBC, serum biochemical analysis, and peritoneal fluid analysis before and 72 hours after the first surgery were used to assess the effects of the procedures on the cows. Exploratory celiotomy was performed 2 weeks after the last laparoscopy. The cows were then reexamined 6 weeks after the last procedure. The t-test for paired data was used for statistical analysis; the level of significance was P < 0.05. Laparoscopy was performed without complication in all cows. Adverse effects of laparoscopy, individually or serially, were not observed. Significant differences were not found between CBC, serum biochemical, and peritoneal fluid variables taken before and 72 hours after surgery.

Vaginal aerobic bacterial flora was studied in 5 healthy bitches before, during, and after a 10-day period of treatment with ampicillin and an equally long period of treatment with trimethoprim-sulfamethoxazole. Blood variables and antimicrobial drug susceptibility also were studied. Bacteria were isolated from all bitches before the first treatment period. Bitches from which only a sparse number of bacteria were isolated had flora that varied from day to day. In most instances when bitches were given an antibiotic to which their vaginal bacterial flora was susceptible, these bacteria were eradicated after only 1 day of treatment. This was true for pasteurellae, streptococci, and, in all but one case, Escherichia coli. Staphylococcus intermedius was more difficult to eradicate, and, although susceptible in vitro, it was unaffected by antibiotic treatment in 1 bitch and it took 7 days to eradicate in another. Eradication of aerobic bacteria in the vagina was total only in the bitch that had sparse flora from the beginning. Bacteria colonized within 0 (in 4/5 bitches) to 4 days after termination of treatment with ampicillin and within 0 (in 4/5 bitches) to 3 days for trimethoprim-sulfamethoxazole. Mycoplasmas emerged during and after both treatment periods, and E coli became apparent during treatment with trimethoprim-sulfamethoxazole. Because mycoplasmas may be genital pathogens in bitches and E coli is a common uropathogen, their appearance should be an argument against widespread use of antibiotics in healthy breeding bitches. Two bitches developed a vaginal discharge during treatment or shortly after. Blood variables did not change during the study, nor did antimicrobial drug resistance of the isolated bacteria.

Two hundred ninety-six Eschericbia coli isolates from feces or intestines of calves with diarrhea were hybridized with 7 gene probes. One probe (the eae probe) was derived from the eae gene coding for a protein involved in the effacement of the enterocyte microvilli by the group of bacteria called attaching and effacing E coli (AEEC), and 2 probes were derived from genes coding for the Shiga-like toxins (SLT) 1 and 2 produced by the verocytotoxic E coli (VTEC). The other 4 probes were derived from DNA sequences associated with the adhesive properties of enteroadherent E coli (EAEC) to cultured cells (the EAF probe for the localized adherence pattern, probes F1845 and AIDA-1 for the diffuse adherence pattern, and the Agg probe for the aggregative adherence pattern). Hybridization results for the eae probe were in agreement, for all but 1 of the 8 isolates, with previously published phenotypic results of microvilli effacement. The latter was previously reported as effacing the microvilli of calf enterocytes, but was eae probe-negative. Two classes of isolates hybridized with the eae probe. Members of a first class (60 isolates) additionally produced a positive signal with 1 or both of the SLT probes (VTEC-AEEC isolates). Isolates hy- bridizing with the eae and the SLT1 probes were the most frequent: 56 isolates (ie, 93% of all VTEC-AEEC). Members of the second class (10 isolates) failed to hybridize with either SLT probe (non-VTEC-AEEC isolates). Most isolates of these 2 classes belong to only 4 serogroups: O5, O26, O111, and O118. In addition to these 2 AEEC classes, a VTEC class (20 isolates) was observed. Such isolates were positive with 1 or both SLT probes, but were negative with the eae probe. All but 1 isolate belonged to serogroups not found among the AEEC isolates. Only 7 of all AEEC and VTEC isolates were positive with the EAF, the F1845, or the AIDA-1 probe, and none were positive with the Agg probe. On the other hand, 32 non-VTEC, non-AEEC isolates were po.

The antibiotic polymyxin B sulfate is a cationic polypeptide with a unique cyclical configuration and distinct cationic characteristics. In this investigation, polymyxin B was evaluated to determine its ability to prevent synthesis of lactic acid and tumor necrosis factor-alpha (TNF-alpha) by lipopolysaccharide-stimulated strain RAW 2647 macrophage-like cell populations. In this context, gradient concentrations of polymyxin B were formulated in the presence of fixed concentrations of lipopolysaccharide fractions from Escherichia coli (B4:0111), E. coli (J5), Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella minnesota, and S. typhimurium (Re). Quantitation of TNF-alpha was established by the application of a tissue culture-based biological assay system, using the WEHI 164 clone 13 indicator cell line. Investigations also included evaluation of the ability of gradient concentrations of lipopolysaccharide fractions from E. coli (B4:0111), E. coli (J5), K. pneumoniae, P. aeruginosa, S. minnesota, and S. typhimurium (Re) to form a complex with polymyxin B. This was established through application of high-performance thin-layer chromatography techniques. On the basis of the known molecular characteristics of lipopolysaccharide, its lipid A-core subfractions, and polymyxin B, these results imply that cytoprotective properties of polymyxin B are attributable to direct interaction and subsequent complex formation. More specifically, the mechanism by which polymyxin B exerts affinity for lipopolysaccharide fractions is proposed to occur through attractive ionic interactions established between the cationic diaminobutyric acid residues of polymyxin B and the mono- or diphosphate group(s) of the lipid A-core moiety. It is highly probable that this molecular phenomenon is accompanied by hydrophobic interactions established between the terminal methyloctanoyl or methylheptanoyl groups of polymyxin B and the saturated carbon chains of the lipid A-core subfraction of lipopolysaccharide fractions.

Newborn pups from 4 large litters were allotted to 6 groups to determine effect of time and route of administration on absorption of an alternate source of immunoglobulin. Selective absorption of specific classes of immunoglobulins was also investigated. The alternate source of immunoglobulin consisted of pooled serum that was administered either PO or SC. Control groups were either left with the dam (group C1) or fed milk replacer (group C2). Blood samples were collected from pups at birth and 24 hours. Immunoglobulin (IgA, IgG, IgM) concentrations were determined by use of radial immunodiffusion on samples of pooled serum, colostrum, and pups' serum (birth and 24 hours). Serum IgA concentration was less than the sensitivity of the procedure and was not included in the statistical analysis. Pups fed 8 ml of pooled serum at birth and 12 hours later (group T1) absorbed more (P < 0.05) IgG and IgM than did group-C2 pups, but less (P < 0.05) than did group-C1 pups. Pups fed 8 ml of pooled serum at 12 hours only had significant (P < 0.05) increase of IgG concentration, but no absorption of IgM (P > 0.05) at 24 hours, compared with control pups (group C2). Pups administered 8 ml of pooled serum SC at birth (group SC1) had similar (P > 0.05) absorption of IgG and higher (P < 0.05) absorption of IgM than did pups of group T1. Pups administered 16 ml of pooled serum SC at birth had the highest increase of IgG and IgM concentrations of all treatment groups, but immunoglobulin concentrations were lower (P < 0.05) than those for group-C1 pups. Absorption of IgG was favored, compared with IgM, when pooled serum was fed. Results indicate clearly that intestinal absorption of immunoglobulins is minimal after 12 hours and thus, another route of administration should be used. Pups in groups SC1 and T1 had similar absorption of IgG, despite lower IgM absorption in pups of group T1. This lower IgM concentration in group-T1 pups may have been the result of selective intestinal absorption or the consequence of low number of pups per group. Subcutaneous administration of 16 ml of pooled serum was the most successful alternative to colostrum, with minimal pain to pups if serum was administered slowly. Serum IgG concentration in C1 pups was higher than expected and probably was attributable to the amount of colostrum available to the pups.

Efficacy of sulbactam, a beta-lactamase inhibitor, in combination with ampicillin, was evaluated for treatment of experimentally induced pneumonia caused by beta-lactam-resistant Klebsiella pneumoniae. Infection was experimentally induced in 18 healthy weanling foals that were randomly allocated to 3 treatment groups: sulbactam plus ampicillin (S/A, 3.3 and 6.6 mg/kg of body weight, respectively), ampicillin (6.6 mg/kg), or vehicle only. Foals were treated daily for 7 days; the observer was unaware of treatment status. Compared with ampicillin and vehicle, treatment with S/A resulted in a statistically significant (P < 0.05) decrease in severity of pneumonia, with regard to bronchoalveolar lavage cytologic findings (decreased total cell and neutrophil numbers, and increased lymphocyte numbers) and extent of macroscopic lesions in lung tissue of the noninoculated regions. Marked trends toward improvement of S/A-treated foals were observed for quantitative results of bacteriologic culture of bronchoalveolar lavage fluid samples (P < 0.07), macroscopic pathologic features of the whole lung (P < 0.1), and histopathologic variables (P < 0.07), compared with ampicillin- and vehicle-treated foals. Treatment effects were not observed for radiographic, hematologic, and blood gas abnormalities that resulted from infection. In conclusion, the combination of sulbactam plus ampicillin was found to have synergistic effects in vivo, to reduce the extent and severity of experimentally induced grain-negative lung infection in foals.

Effect of fluoride was assessed on molars during and after mineralization. Two groups of 7 sheep each were dosed orally with 3.5 mg of fluoride/kg of body weight daily for 4 months (from 5 to 9 months after birth). Sheep of the first group were slaughtered immediately after fluoride administration; those of the second group were slaughtered 4 months later at the age of 13 months. Three control groups of 7 sheep each were slaughtered at 5 months (to determine the state of the teeth at the beginning of fluoride administration), and at 9 and 13 months. During fluoride administration, plasma fluoride concentration rapidly increased to about 0.50 micrograms/ml; after fluoride administration, it stabilized at 0.20 micrograms/ml in treated sheep, whereas controls had concentration of 0.10 micrograms/ml (P < 0.01). Parts of the molars that were in the process of mineralization during fluoride administration (mainly second molars) had thinning enamel, with pits, mainly close to the apex, marked decrease in hardness throughout the layer (< 100 Vickers U, compared with 240 Vickers U), and fluoride accumulation twice as high as that in controls (1,000 to 2,500 mg(kg [dry weight]). Fluoride accumulation was higher in dentine (2,700 to 4,200 mg/kg), but hardness was less affected. On parts of the molars that were already mineralized mostly, the first molar), changes in the appearance of enamel and cementum, decreased hardness (less important than in teeth during mineralization) affecting outer enamel more than inner enamel, high fluoride concentration (4,000 to 5,500 mg(kg [dry weight]) in outer enamel extending over 200 Km were observed. Thus, in sheep, fluoride has a substantial postsecretory effect that may be explained by a slower maturation phase of enamel in this species. Because molar wear is correlated to enamel hardness (dentine at the occlusal surface has low resistance--30 Vickers U), abnormal abrasion of molar teeth that have mineralized before and during fluoride intakes can be observed.

The anthelmintic efficacy of ivermectin (IVM) delivered from a sustained-release (SR) bolus was evaluated against natural infections with gastrointestinal tract nematodes in 12 crossbred beef heifers in spring. The 12 calves were randomly allotted to 2 groups of 6 calves each. Group-1 calves were treated with an SR bolus designed to deliver 8 mg of ivermectin/d. Group-2 calves were nontreated controls. Cattle groups were kept in separate concrete-floored pens (grass hay nutrition) and slaughter was performed at 35 days after treatment. Fecal egg counts for group-1 calves remained zero after treatment, except for detection of < 1 egg/g of feces in 1 calf at the time of slaughter; counts in nontreated calves increased. Mean and range of Ostertagia ostertagi inhibited larvae in nontreated calves were 27,093 and 10,622 to 56,368, respectively. Efficacy of the IVM SR bolus was 100% against O ostertagi developing fourth-stage larvae (L4) and inhibited early L4, Haemonchus placei adults, Cooperia punctata and C spatulata adult males, Cooperia spp adult females, Cooperia spp L4, Trichostrongylus colubriformis adults, Bunostomum phlebotomum adults, and Oesophagostomum radiatum adults. Efficacy for O ostertagi and T axei adults was 99.9%. Numbers of nontreated calves infected with C pectinata adult males and Oes radiatum L4 were too low to evaluate efficacy. Calves treated with the IVM bolus gained 10.2 kg, whereas nontreated calves lost 1.8 kg. Abomasal lesions were dearly greater in nontreated calves on the basis of index comparisons of abomasal weight and total live weight and gross pathologic features.

Four shed-lambing operations in western Colorado were monitored during the 1984 spring lambing season to determine the causes and rates of perinatal lamb mortality. The number of lambing ewes per flock ranged from 513 to 1,712, and lambing percentages ranged from 131 to 180%. Overall perinatal lamb mortality ranged from 8.2 to 12.2%. Most lamb deaths occurred during parturition or within 24 hours after parturition. More than 85% of all lamb deaths were in lambs born to ewes having 2 or more lambs. The leading causes of lamb death were starvation, dystocia, stillbirth (unknown cause), and infectious diseases. A wheel model was used to categorize factors causing lamb deaths into 4 groups: physical, social, host, and biological, and to present data on perinatal lamb mortality in a simple visual model. In all flocks, social and biological factors resulted in most of the lamb deaths. On the basis of our findings, we suggest that interventions designed to improve ewe-lamb bonding and to reduce infectious agents and the incidence of prolonged parturition may reduce lamb mortality.