One hundred and fifty lactating Holstein cows from 2 genetic lines selected for high and average milk production were used in the study. Sera from 6 annual herd tests were analyzed by agar-gel immunodiffusion test for antibodies to bovine leukemia virus. Odds of being seropositive were analyzed by use of stepwise and backward logistic regression procedures. Analysis within birth year revealed that estimated ln odds increased by 0.19/year of age among cows of the high genetic line and by 0.43 among cows of the average genetic line. This was accompanied by a more important cohort effect among high producers than among average producers.

Campylobacter jejuni A74/O and A74/C are congenic strains. An oral dose of 10(5) organisms of strain A74/C colonizes chicken intestines. Strain A74/O, from which A74/C is derived, does not colonize the chicken intestines with an oral dose of 10(5) organisms. In this study, the congenic bacteria were compared to identify possible colonization mechanisms. Differences were not observed in plasmid content or by HindIII, Pst I, Acc I, HincII, Ava I, Ava II, Xba I, and BamHI restriction enzyme digestion of total DNA. Transmission electron microscopy of negatively stained samples revealed no differences between the strains. Sections of cecal tissue from nonfed day-of-hatch chicks were cultured with each strain for 2 hours and then examined by light and electron microscopy. Both strains caused necrosis of villus epithelial cells. Immunofluorescent or silver staining revealed strain A74/C located deep in numerous epithelial crypts, but strain A74/O only was present in one sample mixed with sloughed necrotic cells. Similarly, organisms were detected by transmission electron microscopy deep in crypts in tissues cultured with A74/C, but not A74/O. Cells of A74/C detected in crypts did not appear to associate with epithelial cells. The strains did not differ in chemotactic behavior to mucin or fucose.

A protocol for performing slit-lamp fluorophotometry of the anterior chamber in dogs was established. The technique was then used to develop a model of blood-aqueous barrier disruption that can be used for comparative testing of ophthalmic anti-inflammatory drugs. It was determined that barrier disruption induced by a slow, controlled paracentesis of a small volume of aqueous humor may provide the most reliable model for drug testing. Additionally, fluorophotometry proved to be a sensitive and accurate means of detecting breakdown of the blood-aqueous barrier.

A recombinant cDNA probe from genome segment 5 obtained from a virulent US bluetongue virus strain (BTV-11 strain UC8) was hybridized to US and Israeli BTV prototypes and field isolates. The cloned genetic probe hybridized with US BTV prototype 10, but not with US prototypes 2, 11, 13, and 17; with the avirulent BTV-11 strain UC2; and with the Israeli prototype 10. When the probe was hybridized to field isolates from the US serotypes, it hybridized to 12 of 14 BTV-10 isolates and 4 of 17 BTV-11 samples, but not to the BTV-13 and BTV-17 samples tested. Hybridization was not observed with the Israeli field isolates studied. Results indicate that a reassortant event occurred between a strain of US BTV-10 and US BTV-11 that originated the BTV-11 strain UC8.

A total of 5,142 kidney tissue samples and 5,111 serum samples from mature cattle in 49 states and Puerto Rico were collected at slaughter. Age of cattle ranged from 1 to 16 years (mean, 6.6 years). Leptospires were isolated from 88 (1.7%) kidney tissues, and 2,493 (49%) sera contained antibodies against I or more of 12 Leptospira interrogans serovars. Leptospires were observed by immunofluorescence in 41 (0.8%) kidney tissues. Using agglutinin-absorption tests, 73 (83%) isolates were identified as serovar hardjo, 11 (12.5%) as serovar pomona, and 4 (4.5%) as serovar grippotyphosa. By use of restriction endonuclease analysis studies of chromosomal DNA, all isolates differed from reference serovars but were identical to strains previously isolated from cattle or swine in the United States. Of the serovar hardjo isolates, 85% were identical to restriction endonuclease analysis type (genotype) hardjo-bovis A and 11 (15%) were identical to genotype hardjo-bovis B. Serovar pomona isolates were identical to genotypes kennewicki A (64%) or kennewicki B (36%), and serovar grippotyphosa isolates were identical to the RM 52 strain. Isolation rates were significantly (P < 0.001) higher for beef cattle than for dairy cattle and were higher (P < 0.001) for bulls than for cows. Combined culture and immunofluorescence results indicated that 2% of mature cattle were renal carriers of leptospires.

Because certain inflammatory processes are dependent on the fatty acid composition of the cellular membrane, dietary manipulations that replace omega-6 fatty acids with omega-3 fatty acids may modify inflammatory responses. We investigated the effect of supplemental dietary linseed oil, containing the omega-3 fatty acid, alpha-linolenic acid, on in vivo responses of horses to endotoxin. One group of horses (n = 6) was fed a control pelleted ration (0% linseed oil), and another group of horses (n = 6) was fed an 8% linseed oil pelleted ration. After 8 weeks of consuming these rations, all horses were given 0.03 microgram of Escherichia coli 055:B5 endotoxin/kg of body weight, infused over 30 minutes. Horses were monitored over 24 hours. Compared with baseline values within each ration group, endotoxin infusion caused significant (P < 0.05) increase in rectal temperature, heart rate, and plasma concentration of thromboxane B2, 6-keto-prostaglandin F1 alpha, and fibrinogen and significant (P < 0.05) decrease in total WBC count. Compared with baseline values within each ration group, endotoxin infusion failed to cause significant changes in prothrombin, activated partial thromboplastin, thrombin, or whole blood recalcification times, serum concentration of fibrin degradation products, PCV, or plasma total protein concentration. Before and after endotoxin infusion, horses given the linseed oil ration had longer mean whole blood recalcification time and activated partial thromboplastin time than did horses fed the control ration.

An axial pattern flap that was based on the sternocleidomastoideus branches of the caudal auricular artery and vein was developed. Control flaps, which included ligation and division of the caudal auricular artery and vein, were similarly developed on the contralateral aspect of the neck. Mean survival of caudal auricular artery axial pattern flaps (85.2%), compared with control flaps (63.9%), was significantly different (P < 0.05). On the basis of results of this study, an axial pattern flap based on the sternocleidomastoideus branches of the caudal auricular artery and vein may be a source of skin for reconstructive procedures of the head and neck.

Chemotaxis under agarose was evaluated to establish an assay system and to characterize chemotacticresponses of canine neutrophils. A method for the measurement of canine neutrophil chemotaxis was established, with optimal responses obtained with agarose containing 10% pooled canine serum, a concentration of 5 X 10(5) cells/well, zymosan-activated serum (ZAS), or autologous serum or plasma as the chemoattractants, and a 120-minute incubation period. Canine neutrophils responded well to ZAS, heat-inactivated ZAS, autologous serum and plasma, and heat-inactivated pooled serum. Chemotactic activity was proportional to the concentration of serum used as the chemoattractant. Mean (+/- SD) random migration, chemotaxis, chemotactic index, and chemotactic differential of neutrophils from 9 healthy Greyhounds were 1.09 (+/- 0.23), 1.95 (+/- 0.38), 1.82 (+/- 0.31), and 0.86 (+/- 0.32) mm,respectively.

Analysis of hepatic enzyme activities in serum samples from 1- to 3-day-old pups revealed alkaline phosphatase (ALP) activities that were 30 times higher and gamma-glutamyltransferase (GGT) activities that were 100 times higher than activities in clinically normal adult dogs. A study was conducted to investigate high enzyme activity in pups and to determine whether there is any association between serum enzyme activity and colostrum ingestion, passive transfer of maternal serum enzyme (in colostrum or in utero), or excessive renal or hepatic tissue enzymes. Serum enzyme activity was quantified in 15 neonatal pups before and after ingestion of colostrum and in 3 colostrum-deprived neonates fed a milk substitute. Serum samples were collected on postpartum days 0, 1, 10, 15, and 30. Enzyme activity was also quantified in serum from pregnant and lactating bitches (collected on days - 2, 0, 1, 10, 30), hepatic and renal tissue from clinically normal adult dogs and 1-day-old pups, colostrum, milk (collected on days 10 and 30), and milk replacer. Significant (P < 0.01) differences in serum GGT and ALP activities between colostrum-deprived and suckling pups did not exist before initial feeding. Significant (P < 0.001) increases in serum GGT and ALP activities developed within 24 hours in suckling pups, but not in the colostrum-deprived pups. At 10 and 30 days after birth, serum GGT and ALP activities were less than values before suckling in all pups. Enzyme activities in bitches' serum remained within the normal range for adult dogs throughout whelping and lactation. Renal GGT and ALP activities were substantially greater than hepatic enzyme activities in neonates and adults. Renal tissue from adults contained 3 times greater GGT and 2 times greater ALP activities than that from neonates. Hepatic tissue from neonates contained 5 times more GGT activity than did hepatic tissues from clinically normal adults; however, hepatic ALP activity was similar in adults and neonates. Colostrum and milk bad substantially higher enzyme activities than did bitches' serum. Activities of GGT and ALP in milk were 100 times and 10 times greater, respectively, than activities in serum through day 10. By day 30, GGT and ALP activities in milk were less than before suckling. Enzyme activity was not detected in the milk substitute. These studies reveal an association between colostrum ingestion by suckling and acute, profound increases in serum GGT and ALP in 1- to 3-day-old pups. Although this phenomenon might be useful as an indicator of colostrum ingestion, it precludes the diagnostic use of either enzyme as an indicator of hepatobiliary disease in 3-day-old pups.

Twenty-four-hour excretion of urine metabolites was determined in 33 clinically normal Beagles during periods of consumption of a standard diet and when food was withheld. The goal was to determine normal canine values for urine analytes incriminated in the genesis of calcium oxalate uroliths. During periods when dogs consumed food, daily urinary excretion of calcium, uric acid, sodium, potassium, magnesium, ammonium, and hydrogen ions were significantly (P = 0.0004, 0.0038, O.001, 0.0001, 0.0004, 0.0001, and 0.024, respectively) higher than when food was withheld. Urinary excretion of phosphorus, oxalate, and citrate were not significantly different between samples obtained during periods of food consumption and when food was withheld. Male dogs excreted significantly higher quantities of urine oxalate than females during fed (P = 0.003) and nonfed (P = 0.003) conditions. When food was withheld, urinary uric acid excretion was significantly higher in males than females (P = 0.01). Females excreted significantly more urine calcium than males when food was withheld (P = 0.003). Our results indicated that dietary conditions influence the quantity of sodium, potassium, calcium, magnesium, and uric acid excreted in the urine of clinically normal dogs; therefore, dietary conditions should be considered when measuring the concentration of these analytes in urine.