Changes in Proportion of Canine Urinary Calculi Composed of Calcium Oxalate or Struvite in Specimens Analyzed from 1981 through 2001

The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.

Interrelations of organism prevalence, specimen collection method, and host age, sex, and breed among 8,354 canine urinary tract infections (1969-1995)

Selected information was compiled from canine urinalyses and urine cultures conducted between January 1969 and December 1995. Eight thousand three hundred fifty-four microbial isolates (bacteria and fungi) included 4,873 isolates from females and 3,481 from males. Ten bacterial genera accounted for 96.3% of the urinary isolates, including Escherichia coli (44.1%), Staphylococcus spp. (11.6%), Proteus spp. (9.3%), Klebsiella spp. (9.1%), Enterococcus spp. (8.0%), and Streptococcus spp. (5.4%) as the 6 most common isolates in both genders of dogs. Among these 6 genera, female dogs were generally predisposed over males, although males had more urinary tract infections (UTIs) caused by Klebsiella spp. Distributions of ages at UTI diagnosis tended to be similar between genders. Infection with a single microbial species was responsible for >72% of UTIs in both genders. Among females, 40 breeds and a mixed-breed group represented 90.2% of all positive urine cultures, 88.4% of the individual dogs with UTIs. and 88.2% of the microbial isolations. Among males, these same 41 breed groups represented 87.9% of all positive urine cultures, 87.6% of the individual dogs, and 88.2% of the microbial isolations.

Recurrent and persistent urinary tract infections in dogs: 383 cases (1969-1995)

Laboratory records of bacterial urine cultures from 383 dogs with recurrent or persistent urinary tract infections (UTI) diagnosed at the University of California Veterinary Medical Teaching Hospital (VMTH) between 1969 and 1995 were reviewed retrospectively to characterize the bacteria involved and their association with age, gender, and breed of dogs affected. Sixty-eight breeds and a mixed-breed group were represented. Escherichia coli was the most common isolate, although mixed-bacterial infections were seen in 58% of the female and 55% of the male dogs. Recurrent and persistent UTI were most prevalent in middle-aged to older German shepherd dogs, miniature/toy poodles, and Labrador retrievers, with no apparent sex predilection. Criteria fitting recurrent and persistent UTI were present in 0.3% of all dogs seen at the VMTH during this 26-year period.

Urolithiasis in dogs V: regional comparisons of breed, age, sex, anatomic location, and mineral type of calculus

OBJECTIVE

To determine extent and nature of regional differences in distribution of canine urinary calculi.

SAMPLE POPULATION

13,552 calculus specimens: 7,056 (52.1%) from females, 6,492 (47.9%) from males, and 4 from dogs of unrecorded sex. Procedure Records were used to compile information from all specimens submitted between July 1981 and December 1995. Results from mixed-breed and various breeds of stone-forming dogs were analyzed. Interrelations of breed, sex, and age of dogs, and anatomic location and mineral composition of specimens were analyzed and compared for 6 US geographic regions.

RESULTS

Struvite-, apatite-, and urate-containing calculi were reported significantly most often from female dogs of the Mountain/Pacific region. Oxalate-, silica-, and brushite-containing calculi were reported significantly most often from male dogs in the New England/mid-Atlantic (NEMA) region. Cystine-containing calculi were reported most frequently from the NEMA and South Central (SC) regions. Dogs from the NEMA region were oldest in average age at diagnosis. Significant regional differences in distribution were found for several breeds. Sex distribution of renal calculi in 11 breeds of dogs (Lhasa Apso, Yorkshire Terrier, Shih Tzu, Basset Hound, Pug, Mastiff, Bichon Frise, Doberman Pinscher, Dalmatian, English Bulldog, and Pekingese) reported to be at high risk of renal lithiasis differed among the 6 geographic regions. Renal and ureteral calculi were reported significantly most often from dogs in the South Atlantic region, and bladder and urethral calculi were reported most often from dogs in the SC region.

CONCLUSIONS

Wide regional differences exist in distribution of stone-forming dogs by sex, average age at diagnosis, breed, and minerals contained within and anatomic location of calculi.

Urolithiasis in dogs. II: Breed prevalence, and interrelations of breed, sex, age, and mineral composition

OBJECTIVE

To analyze selected breed-related data for canine urinary calculi.

SAMPLE POPULATION

11,000 specimens: 5,781 from female dogs, 5,215 from males, and 4 from dogs of unrecorded sex.

PROCEDURE

Information was compiled for all canine urinary calculi submitted between July 1981 and January 1994. Results for a mixed-breed group and 26 of the most common breeds of stone-forming dogs were analyzed. Interrelations of breed, sex, and age of affected dogs and mineral composition of the specimens were determined.

RESULTS

Prevalence of 5 specific mineral types was significantly correlated between the sexes of 27 common breed groups: struvite, calcium phosphate (apatite), calcium oxalate, brushite, and urate. Struvite-containing calculi were seen in high proportions in both sexes of 7 breeds, and in low proportions in both sexes of 7 other breeds. Male and female Lhasa Apsos, Cairn Terriers, and 5 other breeds had high proportions of oxalate-containing calculi; values in males were substantially higher. Low numbers of oxalate-containing calculi were seen in both sexes of 7 breeds; Dalmatians had the lowest numbers. Males and females of 6 breeds had high numbers of urate-containing calculi, Dalmatians and English Bulldogs had the highest numbers. Low amounts of urate were found in calculi from males and females of 6 breeds, Samoyeds had the lowest numbers. Highest proportions of cystine-containing calculi were seen in male Dachshunds, English Bulldogs, and Chihuahuas. Males of 8 breeds had no specimens that contained cystine; only 2 such specimens were obtained from females.

CONCLUSIONS

Prevalence of uroliths differs among breed, age, and sex of affected dogs.

CLINICAL RELEVANCE

Breed, sex, and age of dogs; mineral types of calculi in males versus females; and their anatomic location within the tract are important considerations for clinicians when evaluating risk in dogs with urolithiasis and in identifying areas that need further in-depth applied or clinical investigation, or both.

Urolithiasis in dogs. III: Prevalence of urinary tract infection and interrelations of infection, age, sex, and mineral composition

OBJECTIVE

To compile and statistically analyze selected data from a large number of canine urinary calculus specimens that were subjected to quantitative, layer-by-layer mineral analysis.

SAMPLE POPULATION

11,000 canine urinary calculus specimens. 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex.

PROCEDURE

Records of the Urinary Stone Analysis Laboratory, School of Veterinary Medicine, University of California were used to compile information regarding all canine urinary calculus specimens submitted for analysis between July 1981 and January 1994. Interrelations of sex and age of the affected dogs, mineral composition of the specimens, and associated urinary tract infections were analyzed statistically.

RESULTS

Urolithiasis was associated with growth of bacteria isolated from urine or calculi, or both, in 65% of females and nearly 44% of males. Staphylococcus intermedius was isolated most often from either sex (54% for females, 30% for males). In addition to staphylococci, 22 other bacterial species were isolated from specimens from females, and 17 other bacterial species and 1 species of yeast were isolated from males. A single bacterial species was isolated from 87.6% of cultures from females and from nearly 90% of cultures from males. Among females, nearly 98% of pure cultures of staphylococci were associated with calculi that contained struvite; this was true for 80% of pure cultures of staphylococci from males.

CONCLUSIONS AND CLINICAL RELEVANCE

There are wide sex differences in prevalence of urolithiasis- and specific mineral-associated bacterial infections. In several instances, bacterial infections were significantly related to urinary calculus location. These variables should be considered in any evaluation of canine patients that have uroliths.

Urolithiasis in dogs. I: Mineral prevalence and interrelations of mineral composition, age, and sex

OBJECTIVE

To compile and statistically analyze selected data from a large number of canine urinary calculi.

SAMPLE POPULATION

11,000 specimens: 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex.

PROCEDURE

Records were used to compile information from all canine calculi analyzed between July 1981 and January 1994. Interrelations of mineral composition, location of specimens within the urinary tract, age and sex of affected dogs, and number of previous episodes of urolithiasis were determined.

RESULTS

Approximately 70% of the specimens were from a first episode of urolithiasis. Calculi were located in the urinary bladder of 93.1% of females and 79.0% of males, and in the upper urinary tract of 4% of females and 2% of males. Calculi were found in multiple sites in 23.1% of males and 5.2% of females. Significantly higher proportions of struvite, apatite, and urate were found in uroliths from females; oxalate, cystine, silica, and brushite were significantly more prevalent in males. Sixty-one percent of specimens from males and 29% from females were composed of a single mineral substance. The most common mineral combination of 2 or more minerals included struvite and apatite. An additional 67 specimens from male dogs and 49 from female dogs contained other mineral combinations. In 48% of specimens from males and nearly 62% of specimens from females, the minerals formed several distinct layers of differing composition.

CONCLUSIONS

Male and female dogs from urinary calculi composed of 1 or more of several distinct minerals. Prevalence of canine uroliths differs between ages and between the sexes. Many specimens contain complex layering of minerals; most specimens were found in the urinary bladder.

CLINICAL RELEVANCE

Sex and age of dogs, mineral types of likely calculi in males versus females, and their anatomic location are important considerations for clinicians when evaluating risk in dogs with urolithiasis.

Urolithiasis in dogs. IV: Survey of interrelations among breed, mineral composition, and anatomic location of calculi, and presence of urinary tract infection

OBJECTIVE

To compile and analyze selected data from a large number of canine urinary calculus specimens that were subjected to quantitative, layer-by-layer mineral analysis.

SAMPLE POPULATION

11,000 canine urinary calculus specimens: 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex.

PROCEDURE

Records of the Urinary Stone Analysis Laboratory, School of Veterinary Medicine, University of California were used to compile information regarding urinary calculus specimens from dogs. Records surveyed were of all canine calculi submitted for analysis between July 1981 and January 1994. Results analyzed included those of a mixed-breed group and 26 common breeds of stone-forming dogs. Interrelations of breed, sex, and age of the affected dogs, mineral composition of the specimens, and associated urinary tract infections were analyzed statistically.

RESULTS

Proportions of culture-positive specimens were significantly correlated between the sexes (r = 0.494, P = 0.008). Staphylococcus intermedius was isolated most often from either sex, ranging from 36.1% (Basset Hounds) to 67.9% (Pekingese) of cultured specimens from females and 8.7% (Chihuahuas) to 71.4% (Scottish Terriers) of specimens from males. The second most frequently isolated bacterial species, Escherichia coli, ranged from 0% in males of 2 breeds and females of 4 breeds to 25% in Cairn Terrier males and 19.4% in Basset Hound females. Streptococcus spp were the third most frequently isolated bacterial species. Significant correlations between the sexes were found for percentages of calculi located in the urinary bladder (r = 0.490, P = 0.008), and for calculi voided in the urine (r = 0.503, P = 0.006).

CONCLUSIONS

Breed and sex differences in prevalence of urolithiasis- and mineral-associated bacterial infections are numerous. Staphylococcus intermedius was the most common isolate from specimens from all but 3 of 54 breed/sex groupings. For either sex, streptococcal infections were significantly related to proportions of calculi passed in the urine.

Renal calculi in dogs and cats: prevalence, mineral type, breed, age, and gender interrelationships (1981-1993)

Three hundred seventeen specimens of urinary calculi of renal origin from 214 female dogs and 103 male dogs, and 71 specimens of urinary calculi of renal origin from 38 female cats and 33 male cats were submitted for mineral analysis between July 1, 1981, and December 31, 1993. Among dogs, 45 breeds were affected with renal calculi. Thirty-three breeds and a crossbred group were represented among females, but 8 breeds and the crossbred group accounted for 81% of the total. Among male dogs, 30 breeds and a crossbred group were represented, but 7 breeds and the crossbred group accounted for 69% of the total. Among cats, 10 breeds and a crossbred group were represented. Dogs and cats with renal calculi were older than those of 2 comparison population groups. More than one-half of the renal calculi in both dogs and cats were from the 1st known episode of urolithiasis. The risk of formation of renal calculi was found to be higher for cats than for dogs, when compared to other stone-forming cats and dogs (approximately 4.95 per 100 stone-forming cats and 2.88 per 100 stone-forming dogs). Among dogs, breeds at highest risk of developing renal calculi were Miniature Schnauzers, Shih Tzus, Lhasa Aposos, Yorkshire Terriers, and female Pugs. Also at high risk were male Dalmatians and male Basset Hounds. Among small dogs, females generally were at higher risk of developing renal calculi than were males. Regardless of size, terrier breed males generally were at higher risk of developing renal calculi. Breeds of dogs at low risk for development of renal calculi included crossbreds. German Shepherd Dogs, Labrador Retrievers, Golden Retrievers, and female Dachshunds. When only 1 kidney was involved, the risk of left renal calculus was greatest for both dogs and cats, but bilateral renal involvement was relatively common in both species (19% and 9%, respectively). Among dogs, specimens composed of 1 mineral substance (e.g., struvite) occurred more often in males (58.3%) than in females (37.9%). Female dogs formed renal calculi containing struvite or oxalate more often than did males; males formed calculi containing urate more often than did females. Calculi containing oxalate, apatite, or some combination of these minerals predominated among cats; only 1 specimen from 38 female cats and only 4 specimens from 33 male cats contained neither oxalate nor apatite. Crossbred cats were significantly less likely to have renal calculi than were other breeds. A single renal calculus specimen was identified in several uncommon breeds including Tonkinese and Birman cats, and Affenpinscher, Clumber Spaniel, English Shepherd, and Field Spaniel dogs. No significant differences were observed between male and female dogs or between male and female cats with regard to mineral type of the specimen and the presence of urinary tract infection.

Silica-containing urinary calculi in dogs (1981-1993)

Silica-containing urinary calculi obtained from 773 dogs and submitted by veterinarians throughout the United States were analyzed by quantitative crystallographic analysis to determine mineral composition. Specimens were composed of either multiple mineral layers (535 specimens) or 1 mineral layer (238 specimens). Most multiple-layer calculi were composed of 80% or greater silica (300 of 535, 56%) or 20% to 79% silica (184 of 535, 34%) in any mineral layer. Most 1-layer calculi were composed of 100% silica (212 of 238, 89%). Most dogs forming silica-containing calculi were of male gender (679 of 773, 88%). Bacterial cultures of calculus or urine or both were performed on 49% (376 of 773) of the specimens, and bacterial growth was obtained from 37% (139 of 376) of samples cultured. The prevalence of calculus-associated urinary tract infection was 35% (113 of 321) in males and 47% (26 of 55) in females. The gender prevalence for infection with Staphylococcus species was 16% (51 of 321) in males and 33% (18 of 55) in females. The breed and gender of dogs that formed calculi (silica population) were compared with the hospital population (Veterinary Medical Teaching Hospital [VMTH] population) and with a population of calculus-forming dogs (Stonelab population) to determine risk factors for silica calculus formation. For all breeds compared, the ratio of males to females was higher in the silica population. The German Shepherd Dog and Old English Sheepdog were significantly overrepresented when the silica population was compared with either the VMTH population or the Stonelab population. We conclude that male German Shepherd Dogs and Old English Sheepdogs are at increased risk for formation of silica-containing urinary calculi.

Evaluation of factors associated with development of calcium oxalate urolithiasis in cats

OBJECTIVE

To evaluate dietary and environmental factors as potential risk factors for calcium oxalate urolithiasis in cats.

DESIGN

Case-control study.

ANIMALS

84 cats with uroliths composed of at least 90% calcium oxalate and 258 age- and gender-matched control cats.

PROCEDURE

Owners of cats with calcium oxalate urolithiasis and control cats were surveyed between November 1990 and August 1992. Owners completed a standard questionnaire administered during a single telephone interview. Data collected included information regarding signalment, environment, urination and defecation, diet, and medical history.

RESULTS

Calcium oxalate uroliths tended to develop in middle- to older-aged, domestic shorthair cats of typical weight. A gender predilection was not detected. Factors associated with an increase in the risk of calcium oxalate urolithiasis in cats were feeding urine-acidifying diets, feeding a single brand of cat food without providing additional foods or table scraps, maintaining cats in an indoor-only environment, and being of the Persian breed.

CLINICAL IMPLICATIONS

Control of diet and environment may help prevent calcium oxalate urolithiasis.

Twin pregnancy diagnosis in Holstein cows: discriminatory powers and accuracy of diagnosis by transrectal palpation and outcome of twin pregnancies

The objective of this prospective cohort study was to determine the sensitivity, specificity, accuracy, and predictive value of twin pregnancy diagnosis by rectal palpation and to examine fetal survival, culling rates, and gestational lengths of cows diagnosed with twins. In this prospective study, 5309 cows on 14 farms in California were followed from pregnancy diagnosis to subsequent abortion or calving. The average sensitivity, specificity, accuracy, and predictive value of twin pregnancy diagnosis were 49.3%, 99.4%, 96.0%, and 86.1%, respectively. The abortion rate for single pregnancies of 12.0% differed significantly from those for bicornual twin pregnancies and unicornual twin pregnancies of 26.2% and 32.4%, respectively (P < 0.05). The early calf mortality between cows calving with singles (3.2%) and twins (15.7%) were significantly different (P < 0.005). The difference in fetal survival between single pregnancies and all twin pregnancies resulted in 0.42 and 0.29 viable heifers per pregnancy, respectively. The average gestation for single, bicornual, and unicornual pregnancies that did not abort before drying-off was 278, 272, and 270 days, respectively. Results of this study show that there is an increased fetal wastage associated with twin pregnancies and suggest a need for further research exploring management strategies for cows carrying twins.

Reproductive performance in high producing dairy cows treated with recombinant bovine somatotropin

The reproductive performance of 156 cows treated with recombinant bST for two consecutive lactations was assessed as part of a target animal safety study conducted in the San Joaquín Valley of central California. Daily intramuscular administration of 17.2, 51.6, and 86 mg of bST per cow started at d 70 postpartum and ended at dry-off or 305 d postpartum. The AI did not begin until d 70 postpartum. During the first lactation study, multiparous cows treated with bST had significantly decreased pregnancy rates, increased behavioral anestrus, and increased anestrus confirmed by palpation. Treated primiparous cows in first lactation had shorter mean days to first standing estrus. In the second lactation study, cows treated with bST had an increased rate of delayed uterine involution, cystic ovarian condition, behavioral anestrus, and anestrus confirmed by palpation. Progeny from the first lactation cows were evaluated for rates of growth, morbidity, mortality, and for reproductive performance; no difference was detected between the progeny from different groups.

Interval from calving to conception in high producing dairy cows treated with recombinant bovine somatotropin

Intervals from calving to conception in cows treated for two lactations with recombinant bST were ascertained using survival analysis methods. Daily intramuscular administration of placebo, 17.2, 51.6, or 86 mg of bST per cow started at d 70 postpartum and ended at culling or drying off. Breeding began at d 70 postpartum. Multiparous cows treated during the first lactation had significantly longer intervals from calving to conception. Cows treated during the previous lactation, but not during the second lactation, had significantly shorter intervals from calving to conception. Cox proportional hazards regression analysis was used with adjustment for the confounding effect of serum metabolites, milk production, energy balance, and body condition.

Pregnancy incidence in high producing dairy cows treated with recombinant bovine somatotropin

Reproductive performance in cows exposed for two lactations to recombinant bST was measured using unconditional logistic regression. Intramuscular administration of 17.2, 51.6, and 86 mg of recombinant bST/d per cow started at d 70 postpartum and ended at dry-off or 305 d postpartum. Performance was measured as the cumulative incidence of cows becoming pregnant by 305 d post-partum. Within each parity group, cows treated with bST had higher total milk yield. During the first study lactation, the log odds of a cow becoming pregnant decreased linearly as dose increased, following adjustment for serum cholesterol, blood urea N, average daily milk yield, peak milk yield, net energy balance, and body condition score. However, differences in pregnancy incidence between treated and untreated cows were statistically significant only at the higher dose categories, the 51.6 and 86.0 mg of recombinant bST per cow. During the second study lactation, pregnancy rates were similar to those in the first lactation; rates reduced as recombinant bST dose increased. The singular exception was for cows exposed to recombinant bST during the previous lactation but not during the second. In the latter group, previously treated cows had higher pregnancy incidence than did the controls.

Application of enzyme-linked immunosorbent assay for epidemiological studies of diseases of livestock in the tropics of Mexico

This study was conducted at the Centre for Research, Teaching and Extension in Tropical Livestock (Centro de Investigación, Enseñanza y Extensión en Ganadería Tropical) of the Faculty of Veterinary Medicine of the National Autonomous University of Mexico. During the latter part of 1986 and throughout 1988 and 1989, the herd of Holstein x zebu cattle at the University was tested for IgG antibodies to twenty-one viral, bacterial, rickettsial and parasitic agents. Antigens prepared from twenty infectious disease agents were used as the solid phase in an enzyme-linked immunosorbent assay, and the agar gel immunodiffusion procedure was used to test for antibodies against bovine leukaemia virus. The prevalence of IgG antibodies was high (> 50%) for bluetongue virus, Anaplasma marginale and Mycoplasma bovis. Antibodies to Brucella abortus were absent and antibodies against bovine virus diarrhoea virus and infectious bovine rhinotracheitis virus showed a very low prevalence (< 5%). Antibodies to fifteen other antigens showed intermediate prevalence (15-46%). Antibodies to Campylobacter fetus, A. marginale, bluetongue virus, bovine leukaemia virus and Haemophilus somnus displayed seasonal variations. Levels of antibody to bovine leukaemia virus, M. bovis and Listeria monocytogenes exhibited increasing secular trends while antibodies to bovine virus diarrhoea virus and C. fetus showed declining trends. Prevalence of antibodies increased with the age of animals tested. No consistent difference in antibody prevalence was found between three genotypic groups examined.

Urolithiasis in Dalmations: 275 cases (1981-1990)

From July 1, 1981 to December 31, 1990 the Urinary Stone Analysis Laboratory, School of Veterinary Medicine, University of California received 292 urinary calculi from 275 Dalmations (14 females, 14 episodes; 261 males, 278 episodes). The mean age of dogs at the time of the first episode of calculus formation was 4.5 years for males and 5.5 years for females. Bacteria were isolated from 22 of 49 calculi (45%). The bacteria were gram-positive with 2 exceptions; coagulase-positive staphylococci accounted for 62.5% of the isolates. Polarized light microscopy was used to determine the mineral content of the calculi. One hundred ninety three calculi were 100% urate; 78 calculi contained > or = 50% urate in 1 or more layers and were classified as mixed urate calculi; 7 calculi contained < 50% urate in all layers; and 14 calculi contained no urate. The secondary minerals most commonly encountered in mixed urate calculi were struvite (77%, 60 of 78 calculi), and oxalate (17%, 13 of 78 calculi). There were 65 struvite-containing calculi, 16 oxalate-containing calculi, 7 apatite-containing calculi, 5 silica-containing calculi, and 1 calculus specimen was composed of 100% cystine. The risk of forming urate-containing calculi was high in Dalmations, whereas the risk of forming calculi containing other minerals was consistently lower in Dalmations than in other breeds. X-ray diffraction and high pressure liquid chromatography were performed on all calculi from dogs known to have been given allopurinol (n = 19).(ABSTRACT TRUNCATED AT 250 WORDS)

Lumbosacral transitional vertebrae as a predisposing cause of cauda equina syndrome in German shepherd dogs: 161 cases (1987-1990)

The records of 161 German Shepherd Dogs were divided into groups depending on whether there was a radiographic diagnosis of degenerative disk disease (DDD) involving the lumbosacral disk and lumbosacral transitional vertebral segments (TVS) and whether the dogs had cauda equina syndrome (CES). Statistical analysis of the data suggested an association between TVS and CES and an association between DDD and CES. Establishment of confidence intervals revealed the group without either DDD or TVS indicators differed markedly from the other 3 groups of CES relative to the presence of DDD and TVS. There was some overlap in the confidence intervals, but the proportions of CES were higher when DDD and TVS were both evident. This suggests that the important clinical syndrome of CES is at least partially dependent on TVS, which is probably an inherited condition. Because German Shepherd Dogs have a higher frequency of TVS than dogs of other breeds, this partially explains the higher frequency of CES in this breed. Because TVS are probably familial, we suggest the presence of this lesion should be considered in selection of breeding stock. Although it is believed that DDD is partially dependent on the existence of TVS, it is known that DDD can develop in the absence of TVS.

The association between antibody titres against Campylobacter fetus and milk production efficiency in dairy cattle

The association between serological evidence of exposure to Campylobacter fetus and milk production performance was studied in 178 lactating cows from three California Dairy Herd Improvement Association herds using a cross-sectional study design in December 1986. ELISAs were used to determine the antibody titres against Campylobacter fetus, Haemophilus somnus and Leptospira hardjo, which were classified as either negative or positive. The status of a cow as negative or positive against C. fetus and H. somnus represents the serological evidence of natural exposure to the corresponding bacteria. However, the status against L. hardjo was assumed to be the level of vaccinal titre against this organism since all the cows studied had been vaccinated against this agent. The data on demographic and productivity variables relating to the current lactation of the cows were obtained from Dairy Herd Improvement Association individual cow records for December 1986. Four measures of milk production efficiency for the current lactation were used. The status against L. hardjo and other covariates suggested by previous studies were included in modelling the relationships of interest. Stepwise multiple linear regression was used to study the adjusted relationship of C. fetus with each measure of milk production efficiency. Multivariate analyses revealed that the adjusted relationships of C. fetus with the test-day's milk production, the extended 305-day milk production and the relative value of milk production were not significant (p > 0.1). However, after adjusting for possible covariates, C. fetus-positive cows had an average of 7.43% lower mature equivalent milk production than C. fetus-negative cows (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

The association between antibody titres against Campylobacter fetus and reproductive efficiency in dairy cattle

The relationship between the antibody titres against Campylobacter fetus and various indices of reproductive efficiency was studied in a cross-sectional study of 178 dairy cows from three California Dairy Herd Improvement Association herds. Blood samples were collected from the lactating cows during December 1986. Enzyme-linked immunosorbent assays were used to determine the antibody titres of the cow against Campylobacter fetus, Haemophilus somnus and Leptospira hardjo and were classified as either negative or positive. The status of a cow as either negative or positive against Campylobacter fetus and Haemophilus somnus represents serological evidence of natural exposure to the corresponding bacterial agents. However, the status against Leptospira hardjo was assumed to reflect a vaccinal titre since all the cows studied had been routinely vaccinated against this organism in September 1986. The data on demographic and reproductive parameters pertained only to the current lactation of the cows and were obtained from Dairy Herd Improvement Association individual cow records of December 1986. Five indices of reproductive efficiency were used, namely the recent calving interval, the calving-to-conception interval, the calving-to-last-service interval, the number of services per conception, and the number of services since last calving. The serological status against Haemophilus somnus, Leptospira hardjo and other covariates suggested by the results of previous studies were included in modelling the relationships of interest. Stepwise multiple linear regression analyses were carried out to study the adjusted relationship of Campylobacter fetus with each measure of reproductive efficiency. Multivariate analyses revealed that the adjusted relationship for Campylobacter fetus with all five measures of reproductive efficiency was non-significant (p > 0.05). Among the covariates, Leptospira hardjo had a strong and independent relationship with recent calving interval, the unstandardized partial regression coefficient being -0.77. The possible biological mechanisms of these associations are discussed.

Cohort study of natural transmission and two methods for control of caprine arthritis-encephalitis virus infection in goats on a California dairy

A prospective observational cohort study of 361 dairy goat kids was conducted to compare 2 methods of controlling caprine arthritis-encephalitis virus infection under commercial dairy conditions. To compare effectiveness of feeding kids pasteurized milk vs serologic testing and segregation in addition to pasteurized milk feeding, goats were monitored up to the age of 30 months by use of monthly agar gel immunodiffusion testing. Survival analysis methods were used to determine whether age at seroconversion differed between the 2 groups. Significantly lower rates of seroconversion were observed in the segregated group (P < 0.001), compared with the nonsegregated group. Of 193 goats in the pasteurized milk-only group, 146 (75.6%) seroconverted within the 30-month study period, whereas infection was detected in 39 (23.2%) of 168 goats in the test/segregated group. Nonsegregated goats were 3.37 times more likely to seroconvert by 24 months of age, and 70.3% of seroconversions by 24 months of age could be attributed to nonsegregation. For age-specific intervals beyond 180 days of age, 70 to 100% of seroconversions could be attributed to lack of segregation. Cohort life tables for age at seroconversion were reported for each group. Type of colostrum fed, sex, and weaning group (season) were not significantly associated with age at seroconversion. Saanen goats had lower age-specific risk of seroconversion in the nonsegregated group alone and overall. Non-Saanen goats wee 1.5 times more likely to seroconvert than were Saanen goats, when adjusted for a possible confounding effect of weaning group. Results indicate that pasteurized milk feeding and routine test and segregation would be a substantially more effective means of control of the disease in dairy goat herds than would pasteurized milk feeding alone.

Risk factors associated with the incidence of seroconversion to caprine arthritis-encephalitis virus in goats on California dairies

Incidence of seroconversion to caprine arthritis-encephalitis virus (CAEV) was determined for 1,194 goats on 11 dairies, using 2 repeated annual herd tests for CAEV. Current life table methods were used to compare age-specific incidence of seroconversion for pasteurized milk-raised and unpasteurized milk-raised goats. Logistic regression models were used to determine the risk factors associated with CAEV seroconversion, and to estimate odds ratios for seroconversion for various factor levels. Goats raised by unpasteurized milk-feeding methods were 2.5 to 6.7 times more likely to seroconvert than were goats raised by pasteurized milk-feeding methods, depending on the method of comparison. Similarly, 61.6 to 85.0% of seroconversions in yearling goats possibly were attributable to unpasteurized milk feeding. Among yearling goats, CAEV seroconversion was associated with feeding method, breed, and source of goat (herd of origin) when the effect of dairy was considered. In addition to the 6.7 times greater risk of seroconversion for unpasteurized milk-raised goats, yearling goats of the Saanen and Toggenburg breeds were 2.2 and 3.3 times, respectively, more likely to seroconvert than were Alpine yearling goats. Yearling goats purchased from another source were less likely to seroconvert than were yearlings raised on the dairy where they were studied. Among goats > 1 year old, age was associated with risk of seroconversion. Goats that were 3 years old or were > or = 4 years old were 1.7 and 3.2 times, respectively, more likely to seroconvert than were 2-year-old goats, when adjusted for effect of dairy. The effects of dairy were significant (P < or = 0.001) in yearling and older goats.

Cystine-containing urinary calculi in dogs: 102 cases (1981-1989)

One hundred and seven cystine-containing urinary calculi from 1 female and 101 male dogs were analyzed. Cystine-containing calculi accounted for 2% (107 of 5,375) of all canine urinary calculi submitted to the urinary stone analysis laboratory from July 1981 through December 1989. Male dogs that formed cystine calculi were compared with 3 other canine populations to determine whether certain breeds were apparently at increased or decreased risk for cystine calculus formation. In one or more of 3 population comparisons, significantly increased risk of cystine calculus formation was found in Mastiffs, Australian Cattle Dogs, English Bulldogs, Chihuahuas, Bullmastiffs, Newfoundlands, Dachshunds, Basenjis, Australian Shepherd Dogs, Scottish Deerhounds, Staffordshire Terriers, Miniature Pinschers, pitbull terriers, Welsh Corgis, Silky Terriers, and Bichon Frises. Significantly low risk of cystine calculus formation was found in German Shepherd Dogs, Poodles, Schnauzers, and mixed-breed dogs.

Serologic survey for brucellosis in feral swine, wild ruminants, and black bear of California, 1977 to 1989

A retrospective analysis of brucellosis serologic testing results in eight wildlife species in California from 1977 to 1989 was done. Samples were collected from 5,398 live-captured or hunter-killed animals and tested by combinations of up to six serologic tests for antibodies to Brucella spp. Twenty-three of 611 (3.8%) feral swine (Sus scrofa), one of 180 (0.6%) black bear (Ursus americanus), one of 355 (0.3%) California mule deer (Odocoileus hemionus californicus), and one of 1,613 (0.06%) blacktail deer (Odocoileus hemionus columbianus) samples were considered reactors. Suspect serologic reactions occurred in three of 619 (0.5%) desert bighorn sheep (Ovis canadensis nelsoni) and one of 355 (0.3%) California mule deer samples. Brucellosis is not considered an important wildlife health problem in California except in feral swine.

Mass screening of cattle sera against 14 infectious disease agents, using an ELISA system for monitoring health in livestock

Mass screening ELISA methods were developed for testing cattle serum for antibodies against 14 common livestock diseases simultaneously. The absorbance values were transformed to a %ELISA (spectrophotometric antibody end point) by a computer interfaced with a microplate reader. A histogram indicating a cutoff point and a report for the veterinarian also was generated. The computer program produced a print-out of the antibody profile for each animal tested, the antibody concentration against each disease, and a histogram (antibody profile) showing the prevalence of each disease in the herd. Serum samples were obtained from 1,953 cattle, including 880 dairy cattle from 10 herds and 1,073 beef cattle from 20 herds. These samples were obtained from June 1988 through June 1989. The highest antibody prevalence was against bluetongue virus. Of the 1,953 cattle tested, 1,223 (63%) were seropositive for bluetongue virus, including 502 (57%) of the dairy cattle and 721 (67%) beef cattle. Other antibody prevalences, in descending order, were: rotavirus (44%), Pasteurella spp (25%), Leptospira spp and Haemophilus spp (22%), Mycoplasma spp (18%), parainfluenza virus (17%), Campylobacter spp (16%), Anaplasma marginale (15%), bovine leukosis virus (13%), Brucella spp (8%), Mycobacterium paratuberculosis (8%), bovine viral diarrhea virus (3%), and infectious bovine rhinotracheitis virus (3%). Major differences in antibody prevalence between dairy and beef cattle were that only 4% of the dairy cattle were seropositive for A marginale, compared with 25% of the beef cattle, and conversely, 29% of the dairy cattle were seropositive for bovine leukosis virus, compared with 1% of the beef cattle.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of antibiotic and sulfonamide residues in bob veal calf tissues: 967 cases (1987-1988)

The data on antimicrobials in bob veal calves obtained by USDA-Food Safety Inspection Service (FSIS) during the fiscal year 1988 were reviewed. Of 3,095 calf antibiotic and sulfonamide test (CAST)-positive carcass submissions, 967 were chosen by FSIS for antimicrobial residue analyses. Specimens of muscle, liver, and kidney were obtained at abattoirs as a part of the FSIS program, and the results were reviewed by calf submission. At least 1 tissue from each of 425 submissions contained neomycin. Unidentified microbial inhibitors were found in 291 submissions. Streptomycin was found in 86 carcass submissions, penicillin in 81, sulfamethazine in 73, tetracycline HCl in 59, and gentamicin in 53. Other monitored agents were found in less than 50 submissions each. Only 257 submissions included evaluation for sulfonamides, but sulfamethazine was found in 28.4% of them. Chloramphenicol was not detected. Concentrations of neomycin in kidney specimens ranged from 0.25 to greater than 100 ppm, and differed among the 3 regional laboratories (West, Midwest, and East). The western region had the greatest proportion of low-concentration specimens, whereas the midwestern laboratory had the largest proportion of specimens with very high concentrations (greater than or equal to 100 ppm) of neomycin in kidney tissue. Data to identify the sources and causes of the residues were not available. However, the western laboratory evaluated CAST-positive submissions from calves certified to be antimicrobial-free, whereas the other laboratories evaluated submissions from certified and noncertified calves; therefore, this may partially explain regional patterns for neomycin quantities in kidney specimens. Neomycin predominated among CAST-positive verifications. A high prevalence of unidentified microbial inhibitors suggests further identification may be warranted.

Antibiotic and sulfonamide agents in bob veal calf muscle, liver, and kidney

During the fiscal year 1988, USDA-FSIS detected 3,095 antimicrobial violations in bob veal calves, using the calf antibiotic and sulfonamide test. Of the 3,095 carcass submissions involved, 945 were tested further to identify the causative agents. The results of tests on the available kidney, liver, and muscle specimens are reported. Kidney specimens yielded a specific agent most often (71.2%), with neomycin (42.6%) being cited most among agents found in kidneys. Neomycin was found less frequently in liver (4.5%) and muscle (0.2%). Among all tissues, unidentified microbial inhibitors were either the largest or second largest category found (kidney, 10.5%; liver, 27.1%; muscle, 7.8%), and no other agent exceeded 7.0% (streptomycin in kidney). The proportion of liver and muscle specimens that had unidentified microbial inhibitors is particularly important because the next most common classes were streptomycin in liver at 5.5% and sulfamethazine in muscle at 2%. The frequency of unidentified microbial inhibitors may justify the addition of tests to the FSIS battery for identification of agents. Not all tissues were tested for sulfonamides, hence these agents are likely to have been underreported. Less than 10% of the muscle specimens evaluated yielded an agent, suggesting most calf antibiotic and sulfonamide test-positive carcasses may have been safe with regard to residues in meat, although organs might have been adulterated. Specimens for verification were not selected completely randomly from the population of all calf antibiotic and sulfonamide test-positive animals and calves selected for testing were not chosen strictly by random sampling; therefore, extrapolation of the contents of this report to the bob veal calf industry must be done with caution.

Chronic oral infections of cats and their relationship to persistent oral carriage of feline calici-, immunodeficiency, or leukemia viruses

Two hundred and twenty-six cats from the Veterinary Medical Teaching Hospital (VMTH), a cat shelter, and a purebred cattery were tested for chronic feline calicivirus (FCV), feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) infections. Chronic oral carriage of FCV was present in about one-fifth of the cats in each of the groups. FIV infection was not present in the purebred cattery, was moderately prevalent (8%) in the pet population of cats examined at the VMTH for various complaints and was rampant in the cat shelter (21%). Unexpectedly high FeLV infection rates were found in the hospital cat population (28%) and in the purebred cattery (36%), but not in the cat shelter (1.4%). FCV and FeLV infections tended to occur early in life, whereas FIV infections tended to occur in older animals. From 43 to 100% of the cats in these environments had oral cavity disease ranging from mild gingivitis (23-46%), proliferative gingivitis (18-20%), periodontitis (3-32%) and periodontitis with involvement of extra-gingival tissues (7-27%). Cats infected solely with FCV did not have a greater likelihood of oral lesions, or more severe oral disease, than cats that were totally virus free. This was also true for cats infected solely with FeLV, or for cats dually infected with FeLV and FCV. Cats infected solely with FIV appeared to have a greater prevalence of oral cavity infections and their oral cavity disease tended to be more severe than cats without FIV infection. FIV-infected cats that were coinfected with either FCV, or with FCV and FeLV, had the highest prevalence of oral cavity infections and the most severe oral lesions.

Antibiotic and sulfonamide residues from Food Safety Inspection Service bob veal calf tissues by region, from October 1987 to September 1988

Of 3,095 bob veal carcasses declared positive to the calf antibiotic and sulfonamide test (CAST) performed by USDA-FSIS personnel during the fiscal year 1988, 967 were submitted to USDA-FSIS laboratories for intensified antimicrobial evaluation of kidney, liver, and muscle specimens. In the western region, CAST-positive specimens were analyzed from certified calves, that is, calves declared free of antimicrobials by their producers. In the midwestern and eastern regions, 20% of the CAST-positive carcass submissions were certified and 20% had not been certified. Among the regions, neomycin was the most commonly reported agent from kidney specimens; however, there were some distinct differences among regions (24.6% of the specimens in the Midwest, 37.4% in the East, and 46.8% in the West). Reports of gentamicin in specimens also were different among regional laboratories (9.0% in the Midwest, 12.1% in the East, 3.1% in the West). Sulfamethazine was less frequently reported by the western laboratory, never exceeding 2% among the 3 tissues tested, whereas the eastern and midwestern laboratories had at least 1 tissue type that was greater than or equal to 9%. Not all specimens were subjected to sulfonamide evaluation. Regional patterns were noticed for unidentified microbial inhibitors, which were most evident for liver in which 24.6% of the specimens at the western laboratory were classified as having unidentified microbial inhibitors, and only 6.3% of specimens at the eastern laboratory were classified as having unidentified microbial inhibitors.

Serum glucose and insulin responses to an insulin-containing ophthalmic solution administered topically in clinically normal cats

Serum glucose and immunoreactive insulin concentrations were monitored after topical administration of an insulin-containing ophthalmic solution in 20 clinically normal cats. Three ophthalmic surface-acting agents, benzalkonium chloride, dimethyl sulfoxide, and proparacaine hydrochloride, were evaluated individually for their effectiveness in enhancing absorption of topically applied insulin. The ophthalmic effects of insulin-containing ophthalmic preparations were assessed by complete ophthalmic examination before and at the conclusion of each test period. Withholding of food overnight (12 hours) preceded each topical application of insulin-containing ophthalmic solution (12.25 to 26.4 U/cat), either alone or in combination with surface-acting agents, after which blood samples were drawn serially from an indwelling IV catheter over a period of 8 hours. Baseline serum insulin concentration, after food was withheld for 12 hours, in nonstressed cats was 6.0 microU/ml (geometric mean), and an exponentiation of the logarithmic quantity (mean +/- SD) yielded values of 1.5 to 23.0 microU/ml. All ophthalmic solutions tested failed to significantly lower serum glucose concentration or increase serum insulin concentration. Solutions used did not induce deleterious effect on ocular structures. Results indicate that topical administration of insulin-containing ophthalmic solution, either alone at the concentrations used or in combination with surface-acting agents, did not result in effective absorption of insulin across the conjunctival and lacrimal nasal mucosa in biologically relevant quantities. Thus, this route of insulin administration, under these specific conditions, is not an effective alternative or adjunct to SC administration of insulin for treatment of cats with insulin-dependent diabetes mellitus or severe noninsulin-dependent diabetes mellitus.

Risk factors associated with caprine arthritis-encephalitis virus infection in goats on California dairies

Log-linear methodology was used to examine relations among caprine arthritis-encephalitis virus (CAEV) seroreactivity and host/management factors in a cross-sectional study of 2,826 goats on 13 California dairies. The CAEV serologic status was associated with age and feeding method (pasteurized/unpasteurized milk), but not with breed. Data from a prevalence survey of 321 goats from 2 additional dairies demonstrated very good fit of the selected log-linear model (P = 1.00), indicating that the model was very appropriate to describe the relations. Odds of seropositivity and odds ratios were generated by use of a logit model derived from the log-linear model. Goats raised by the unpasteurized feeding method were estimated to have been 3.3 times more likely to be CAEV-seropositive than goats fed by the pasteurized method, when adjusted for the effects of age. Goats aged 2, 3, 4, and 5 or greater years were estimated to have been 1.7, 2.6, 4.5, and 5.7 times, respectively, more likely to be CAEV-seropositive than were yearling goats when ratios were adjusted for pasteurization status. Breed, gender, and herd of origin were not associated with CAEV seroreactivity when the effects of other factors were considered. Estimated odds of CAEV seroreactivity and the associated odds ratios for combinations of factor levels are reported. In this study, the magnitude and direction of the associations among CAEV serologic status, age, and pasteurized feeding methods were demonstrated.

The use of loglinear model to evaluate factors associated with sero-prevalence of Campylobacter fetus in dairy cattle

Campylobacter fetus is one of the leading infections causing bovine infertility and abortion. In a cross-sectional study, the associations of parity, herd, serological status against Leptospira hardjo and Haemophilus somnus with the sero-prevalence of Campylobacter fetus in dairy cattle were evaluated. Four hundred dairy cows from three herds were included in the study. Blood samples from the cows were collected in December 1986. An enzyme-linked immunosorbant assay (ELISA) was used to determine positive or negative status of cows against Campylobacter fetus , Haemophilus somnus and Leptospira hardjo antigens. Loglinear analysis was used to describe the relationship of four categorical variables with the sero-prevalence of Campylobacter fetus . The final loglinear model was interpreted as a logit model. The final loglinear model included a three-way interaction among Campylobacter fetus , Leptospira hardjo and herd and a two-way interaction between Campylobacter fetus and parity. The adjusted odds of being a positive Campylobacter fetus reading were highest for cows with parity >6 (e.g. 27.8, 95% confidence interval (CI) = 12.9, 60.1); it was next highest for cows in parity <4 (e.g. 18.0, 95% CI = 13.5, 24.2); and it was lowest for cows in parity 4 to 6 (e.g. 13.3, 95% CI 7.3, 24.4). The herd management practice that was associated with the carrier state in early and late parities is identified in the study, and the biological implication of a three-way interaction among Campylobacter fetus , Leptospira hardjo and herd are discussed.

Epizootiologic evaluation and quantitative analysis of urinary calculi from 150 cats

One hundred fifty specimens of urinary calculi from 150 cats were analyzed by at least 1 of 4 quantitative methods. Struvite (magnesium ammonium phosphate) was the predominant mineral substance encountered, with 104 (69%) of the calculi being composed entirely of struvite and 23 (15%) being composed partially of struvite. Most (93%) of the calculi were located in the urinary bladder. Growth of bacteria was observed in samples from calculi or urine from 30 (41%) of 74 cats. Coagulase-positive staphylococci were isolated from the urine or calculi from 17 cats (45% of bacteria isolated). Ten other bacterial species were isolated. Median and mean ages of the cats were 5.0 and 5.1 years, respectively. Domestic short-hair and domestic longhair breeds predominated. Fifty-seven percent of the calculi came from females, 43% from males. The distribution by gender did not differ significantly (P greater than 0.2) among the 3 groups (domestic shorthair, domestic longhair, and other). However, the distribution of struvite calculi differed significantly (chi 2 = 15.5, P less than 0.001) by age and gender; among cats less than or equal to 2 years of age, males predominated 2:1 over females, and among cats greater than 2 years of age, females predominated by nearly 3:1 over males. When compared with the general population, females greater than 2 years old were significantly (chi 2 = 15.4, P less than 0.001) overrepresented.

The effect of a control program for enzootic bovine leukosis. Changes in herd prevalence in Denmark, 1969-1978

As part of the Danish control program for enzootic bovine leukosis, three hematologic screenings of all cattle herds in Denmark were performed in the period 1969-1978. Herds with multiple cases of persistent lymphocytosis and/or leukotic tumors were classified as "leukosis herds." During nationwide blood testing, 369 leukosis herds were discovered, and an additional 77 herds were found due to follow-up of tumor cases or special testing in connection with movements of cattle in 1969-1978. In the present study, the prevalence of leukosis herds in the three screening rounds is related to geographic area and herd size. By means of a statistical log-linear model, the authors show that prevalence increased proportionally with herd size. The observed number of leukosis herds per 10,000 herds tested declined during the screening program from 105 to 38 in east Denmark and from 12 to 4 in west Denmark.

A cross-sectional study of bluetongue virus and Mycoplasma bovis infections in dairy cattle: II. The association between a positive antibody response and reproduction performance

In a cross-sectional study to determine the possible relationship between a positive antibody test to bluetongue virus (BTV) or Mycoplasma bovis infections and reproductive performance of dairy cows, data were collected on 572 California dairy cows during December 1986 for analysis. Serum samples were tested using an enzyme-linked immunosorbent assay (ELISA). Data on reproduction variables were extracted from the individual cow sheets of the California Dairy Herd Improvement Association records and interfaced with the serological results for analysis. Similar data analyses for both BTV and M. bovis were performed to identify and quantitatively assess the association of the reproduction variables and each agent. These associations were evaluated unconditionally using the chi 2 for categorical variables and Student's t-test for continuous variables. Logistic regression analysis was used to determine if reproduction variables with significant unconditional associations remained significant when adjusted for the effects of possible confounding factors. Both the BTV and M. bovis ELISA antibody titres indicated exposure to the agents. The results of the multiple logistic regression analyses indicated that cows seropositive for BTV were significantly older at first calving (p less than 0.03). For M. bovis, seropositive cows were more likely to have longer intervals from calving to last service and longer intervals from calving to pregnancy diagnosis than seronegative cows (p less than 0.05). The other reproduction variables examined were not significantly associated with ELISA seropositivity.

A cross-sectional study of bluetongue virus and Mycoplasma bovis infections in dairy cattle: I. The association between a positive antibody response and production efficiency

In a cross-sectional study of bluetongue virus (BTV) and Mycoplasma bovis (M. bovis) infections, a sample of 572 California dairy cows was tested for the presence of antibodies to answer the question: Is it possible to identify and to assess quantitatively the associations between positive antibody test and production? Serum samples collected from these cows during December 1986 were tested for the presence of antibodies to BTV and M. bovis using the enzyme-linked immunosorbent assay (ELISA). Data on milk production were extracted from individual cow sheets of the California Dairy Herd Improvement Association (DHIA) record-keeping system and interfaced with percentage ELISA results for analysis. Univariate and multivariate statistical analyses, using the chi 2 test for categorical variables or Student's t-test for continuous variables and multiple logistic regression respectively, were carried out to evaluate for possible associations between positive antibody tests to each agent and each production variable of interest. Complete data on all variables studied were obtained for 289 (50.5%) cows for M. bovis and 423 (74%) cows for BTV. For cows with complete data on all variables, estimates of the point prevalence of antibodies to BTV and M. bovis were 70.5% and 66.1%, respectively. Results of this study indicated that Guernsey cows were more likely to have a positive BTV test than Holstein cows and that cows in higher lactations were more likely to test positive to BTV ELISA than those in lower lactations (p less than 0.05). Because all cows except those on one farm were Holstein, our confidence in the effect of breed is limited. The association between lactation number and BTV seropositive test may be an age factor identified earlier in the study. For M. bovis, the results of the analysis indicated that seropositive cows were more likely to produce less milk, on a mature equivalent basis (ORadj = 0.96, p = 0.034), and that they had less extended 305 day milk production potential (ORadj = 0.90, p less than 0.0001) than seronegative cows.

Regional distribution of ten common skin diseases in dogs

We investigated the regional distributions of the most commonly diagnosed skin diseases in dogs from 17 North American veterinary teaching hospitals. Between January 1983 and December 1983, 11,456 diagnoses of skin disease were made. The 10 most common diagnoses were fleabite allergic dermatitis, skin cancer, pyoderma, seborrhea, allergy, demodectic acariasis (demodicosis), sarcoptic acariasis, immune-mediated skin disease, endocrine related skin disease, and acral lick dermatitis. Regional differences in the frequency of skin diseases were apparent. The northeast region had high frequencies of fleabite allergic dermatitis, allergy, and immune-mediated disease, and a low frequency of seborrhea. The midwest had a high frequency of seborrhea, and low frequencies of demodectic acariasis and allergy. In the plains region, low frequencies of fleabite allergic dermatitis, pyoderma, seborrhea, allergy, and demodectic acariasis were detected. In the west, the frequencies of fleabite allergic dermatitis, skin cancer, pyoderma, seborrhea, and acral lick dermatitis were high, whereas few dogs had allergic disease and sarcoptic acariasis. The southwest had high frequencies of fleabite allergic dermatitis and demodectic and sarcoptic acariasis. Fleabite allergic dermatitis, pyoderma, and demodectic and sarcoptic acariasis were frequently diagnosed in the southeast, but the number of dogs with seborrhea was low.

Neonatal survival in swine: effects of low birth weight and clinical disease

Data were collected for 3,636 full-term pigs born in a commercial swine herd to determine the effects of birth weight and clinical disease on survival during the first 3 weeks of life. Logistic regression models were constructed for 7-day survival for all live-born pigs, and for 21-day survival for pigs surviving the first week of life. Estimates of birth weight and disease effects were adjusted simultaneously for other risk factors including litter size, parity, and within-litter variation in birth weight. The 7-day survival model indicated that survival odds improved significantly with increasing birth weight. Maximal survival, relative to pigs weighing less than 601 g at birth, was evident in pigs weighing greater than 2 kg at birth (odds ratio [OR] = 349). Diarrhea (OR = 2.7) and splayed limbs (splay leg; OR = 37.3) significantly (P less than 0.05) reduced 7-day survival. Models of 21-day survival indicated a smaller, but still significant, effect of birth weight on survival. Adjusted survival odds for pigs in the heaviest weight group (greater than 2 kg) were 20.1 times higher than pigs weighing less than 801 g. Diarrhea (OR = 2.7) and lameness (OR = 2.6, 2 limbs) significantly (P less than 0.05) decreased 21-day survival.

Randomized efficacy trials of long-acting oxytetracycline in neonatal pigs

Prophylactic efficacy of 100 mg of long-acting oxytetracycline (OTC) given IM to neonatal pigs within 12 hours of birth was evaluated in a swine herd. The herd had a history of increased neonatal mortality, diarrhea, foot abscess, and arthritis in nursing pigs. Two trials were conducted in which liters and individual pigs were the treatment groups of interest. In both trials, OTC treatment failed to reduce mortality, diarrhea, or arthritis or the need for subsequent antimicrobial therapy (P greater than 0.05). Preweaning weight gains were not increased (P greater than 0.05) in treated pigs. However, in the individual pig trial, foot abscess rates were significantly (P = 0.01) lower in treated pigs (3.7%) than in nontreated pigs (8%). Aerobic bacteria isolated from pigs with diarrhea, arthritis, or foot abscess had minimum inhibitory concentrations for OTC greater than or equal to 64 micrograms/ml or were classed as resistant on the basis of disk-diffusion tests.

Unsuccessful Burch retropubic urethropexy: a case-controlled urodynamic study

A retrospective comparison was made of the urodynamic parameters of urethral sphincteric function of 21 women with failure of modified Burch retropubic urethropexy and 21 matched control subjects in whom operation was successful. The match criteria included multiple risk factors that contributed to the failure of antiincontinence surgery. The preoperative resting urethral closure pressure and urethral functional length were significantly lower in the study (failure) group than in the control (success) group. These parameters of intrinsic urethral function improved only in the control (success) group after operation. Further study showed that 17 of the 21 patients (81%) in the control (success) group had preoperative closure pressure greater than 20 cm H2O, whereas only five of the 21 patients (24%) in the study (failure) group had initial closure pressure higher than this value. Identification of a low-pressure urethra by preoperative urethral profilometry suggests a greatly increased risk for operative failure.

Patterns and determinants of rectal prolapse in a herd of pigs

A prospective cohort study was designed to describe the patterns and to determine the factors associated with the risk of rectal prolapse in a commercial swine herd in California, USA. Thirty (1.0 per cent) of 2862 pigs prolapsed between 12 and 28 weeks of age with the peak incidence occurring in 14- to 16-week-old pigs. The overall prolapse rate was 9.1 cases per 100,000 days at risk. Prolapse rates were highest during the winter and autumn months. Other factors associated with an increased risk of prolapse were maleness (relative risk 2.3) birthweight less than 1000 g (relative risk 3.4) Yorkshire boar A (relative risk 2.8) and dams of litter number 1 (relative risk 14.9), 2 (relative risk 8.2) and 3 (relative risk 9.8). No evidence was found to support the hypothesis that diarrhoea and coughing are factors associated with a risk of prolapse.

Prevalence of udder infections and mastitis in 50 California dairy herds

The California mastitis test (CMT) and bacteriologic culture were performed on samples of bulk-tank milk and cow-composite milk (n = 23,138 cows) from 50 California dairies, 19 of the 50 with known mastitis problems. Thirty-eight (76.0%) bulk-tank milk samples and 12,334 (53.3%) cows were positive by results of the CMT. Potential mastitis agents were isolated from 5,085 (22%) cows. Staphylococcus aureus was isolated from all 50 herds, Streptococcus agalactiae was isolated from 47 herds, and Mycoplasma sp was isolated from 24 herds. For cow-composite milk samples, the prevalences were 9.3% for Str agalactiae, 9.1% for S aureus, 0.9% for Mycoplasma sp, 1.2% for coliform bacteria, 0.9% for other streptococci, 0.8% for coagulase-negative staphylococci, and 1.3% for other organisms. The relative sensitivity and the relative specificity of the CMT performed on cow-composite milk samples were 83.4% and 55.2%, respectively, and the predictive value of positive CMT results was 34.2%.

Hematologic and serum biochemical alterations associated with multiple halothane anesthesia exposures and minor surgical trauma in horses

Five horses were anesthetized similarly by use of xylazine, guaifenesin, thiamylal sodium, and halothane in oxygen on 3 consecutive days, and minor surgical procedures were performed. For 1 to 10 days after the last anesthetic exposure, clinical, hematologic, and serum biochemical features were monitored, and after necropsy, histologic examination of major organ tissues was performed. Predominant hematologic changes from base-line values included leukocytosis (maximal at 27 hours, 10,500 +/- 1,750 cells/microliter), neutrophilia (maximal at 51 hours, 7,485 +/- 1,719 cells/microliter), and lymphopenia (minimal at 51 hours, 1,636 +/- 564 cells/microliter). Alterations observed in other clinicopathologic features were minor and indicative of mild renal disturbance and nonspecific cellular necrosis. Histopathologic lesions in the liver were mild.

Improved estimates of discordance ratios in twin studies

In the study of monozygotic twins relative to disease and risk factors, particular interest focuses on the subset who are discordant for some suspected risk factor (for example, smoking), since such twins constitute a natural case-control pair. In such studies, questionnaires designed to identify the status of all twin pairs are sometimes error prone and can yield misleading estimates of the concordance-discordance ratios. Greater efforts to verify the characteristics of apparently discordant pairs than to verify those of apparently concordant pairs can result in the 'unequal ascertainment' fallacy. Using the results of a questionnaire with known error rates and the 'apparent' frequencies yielded, we present unbiased, maximum likelihood estimates of the 'true' proportions of concordant and discordant pairs. concordant and discordant pairs. We also present approximate covariances among these estimates.