Toxic tall fescue grazing increases susceptibility of the Angus steer fecal microbiota and plasma/urine metabolome to environmental effects

Impaired thermoregulation and lowered average daily gains (ADG) result when livestock graze toxic endophyte (Epichloë coenophialum)-infected tall fescue (E+) and are hallmark signs of fescue toxicosis (FT), a disease exacerbated by increased temperature and humidity (+temperature-humidity index; +THI). We previously reported FT is associated with metabolic and microbiota perturbations under thermoneutral conditions; here, we assessed the influence of E+ grazing and +THI on the microbiota:metabolome interactions. Using high-resolution metabolomics and 16S rRNA gene sequencing, plasma/urine metabolomes and the fecal microbiota of Angus steers grazing non-toxic or E+ tall fescue were evaluated in the context of +THI. E+ grazing affected the fecal microbiota profile; +THI conditions modulated the microbiota only in E+ steers. E+ also perturbed many metabolic pathways, namely amino acid and inflammation-related metabolism; +THI affected these pathways only in E+ steers. Integrative analyses revealed the E+ microbiota correlated and co-varied with the metabolomes in a THI-dependent manner. Operational taxonomic units in the families Peptococcaceae, Clostridiaceae, and Ruminococcaceae correlated with production parameters (e.g., ADG) and with multiple plasma/urine metabolic features, providing putative FT biomarkers and/or targets for the development of FT therapeutics. Overall, this study suggests that E+ grazing increases Angus steer susceptibility to +THI, and offers possible targets for FT interventions.

Calf Clinical Model of Cryptosporidiosis for Efficacy Evaluation of Therapeutics

Cryptosporidiosis, caused by the apicomplexan parasite Cryptosporidium parvum, is a moderate-to-severe diarrheal disease now recognized as one of the leading causes of morbidity and mortality in livestock globally, and in humans living in resource-limited parts of the world, particularly those with AIDS or malnourished individuals. This recognition has fueled efforts for the discovery of effective therapeutics. While recent progress in drug discovery has been encouraging, there are presently no acceptably effective parasite-specific drugs for the disease. The urgent need for new drug discovery or drug repurposing has also increased the need for refined animal models of clinical disease for therapeutic efficacy evaluation. Here, we describe an acute model of cryptosporidiosis using newborn calves to evaluate well-defined clinical and parasitological parameter outcomes, including the effect on diarrhea severity and duration, oocyst numbers produced, and multiple measures of clinical health. The model is highly reproducible and provides unequivocal direct measures of treatment efficacy on diarrhea severity and parasite replication.

Urine metabolic fingerprinting can be used to predict the risk of metritis and highlight the pathobiology of the disease in dairy cows

INTRODUCTION

Metritis is an uterine pathology that causes economic losses for the dairy industry. It is associated with lower reproductive efficiency, increased culling rates, decreased milk production and increased veterinary costs.

OBJECTIVES

To gain a more detailed view of the urine metabolome and to detect metabolite signature in cows with metritis. In addition, we aimed to identify early metabolites which can help to detect cows at risk to develop metritis in the future.

METHODS

We used nuclear magnetic resonance spectroscopy starting at 8 and 4 weeks prior to the expected day of parturition, during the week of diagnosis of metritis, and at 4 and 8 weeks after diagnosis of metritis in Holstein dairy cows.

RESULTS

At 8 weeks before parturition, pre-metritic cows had a total of 30 altered metabolites. Interestingly, 28 of them increased in urine when compared with control cows (P < 0.05). At 4 weeks before parturition, 34 metabolites were altered. At the week of diagnosis of metritis a total of 20 metabolites were altered (P < 0.05). The alteration continued at 4 and 8 weeks after diagnosis.

CONCLUSIONS

The metabolic fingerprints in the urine of pre-metritic and metritic cows point toward excretion of multiple amino acids, tricarboxylic acid cycle metabolites and monosaccharides. Combination of galactose, leucine, lysine and panthotenate at 8 weeks before parturition might serve as predictive biomarkers for metritis.

Screening and Confirmatory Analyses of Flunixin in Tissues and Bodily Fluids after Intravenous or Intramuscular Administration to Cull Dairy Cows with or without Lipopolysaccharide Challenge

Twenty cull dairy cows (645 ± 83 kg) were treated with 2.2 mg/kg bw flunixin by intravenous (IV) or intramuscular (IM) administration with, or without, exposure to lipopolysaccharide in a two factor balanced design. The usefulness of screening assays to identify violative flunixin levels in a variety of easily accessible ante-mortem fluids in cattle was explored. Two animals with violative flunixin liver residue and/or violative 5-hydroxy flunixin milk residues were correctly identified by a flunixin liver ELISA screen. Oral fluid did not produce anticipated flunixin concentration profiles using ELISA determination. One cow that had liver and milk violative residues, and one cow that had a milk violation at the prescribed withdrawal period were correctly identified by flunixin milk lateral flow analyses. The ratio of urinary flunixin and 5-hydroxy flunixin may be useful for predicting disruption of metabolism caused by disease or other factors potentially leading to violative liver flunixin residues.

Evaluation of some selected herbs on arsenic-affected cattle in Nadia District, West Bengal, India

Arsenic poisoning due to contaminated subsoil water is one of the most alarming environment hazards in West Bengal, India. Cattle are also affected by arsenic due to ingestion of arsenic contaminated water, paddy straw, crops and vegetables. Thirty milch cattle having arsenic content in the range of 3.5 to 4.5 mg/kg in hair were chosen for this experiment from cattle of five respective villages in Nadia District, West Bengal, India. The cattle were divided into three groups containing 10 animals each. Group I cattle were treated with turmeric powder (Curcuma longa) 20 g/day orally for 60 days. Group II cattle were treated with turmeric powder (10 g/day) and Amaranthus spinosus powder (10 g/day) orally for 60 days. Group III cattle were treated with turmeric powder (10 g/day) and Eclipta alba powder (10 g/day) orally for 60 days. Ten apparently healthy milch cows with no history of exposure to arsenic were selected and kept as control group (group IV). Arsenic content in hair, faeces, urine and milk; different biochemical and haematological parameters and DNA fragmentation percentage assay were carried out before commencement of the treatment, after 30 days and after 60 days of treatment. The test drugs were found significantly (p < 0.05) effective to eliminate arsenic from the body and lead to significant improvement in different biochemistry, pathology and DNA fragmentation assay. These drugs also give protection from possible damage caused by arsenic exposure.

[Renal function tests in milk fed calves--reference values and influence of bovine neonatal pancytopenia (BNP)]

OBJECTIVES

Renal function tests were performed on 38 clinically healthy Holstein calves aged 1435 days, of which seven had survived bovine neonatal pancytopenia (BNP). The main objective was the establishment of reference values for renal fractional excretions (FE) of sodium (Na), potassium (K), calcium (Ca) and phosphate (P) in calves fed milk replacer. Additionally, it should be clarified whether calves suffer from permanent renal disorders as a result of BNP.

MATERIAL AND METHODS

The fractional excretions were determined using wet chemical analyses of simultaneously taken urine and blood samples. Their calculation was based on the endogenous excretion of creatinine.

RESULTS

There were no significant differences in the FE between calves with and without a history of BNP. Based on the values of all 38 calves, reference values were calculated for the FE indicated above, and also for the urinary γ-glutamyltransferase-creatinine ratio as a parameter for the damage of tubular cells.

CONCLUSION

It has been demonstrated that age- and feeding-specific reference values for renal function parameters in cattle are necessary. For renal function analyses in calves, the nutritional supply with electrolytes has to be considered to differentiate the variability of electrolyte excretions due to different feeding regimes from renal disorders. Based on the calculated reference values for calves fed milk replacer, renal function disorders can be determined sensitively and further differentiation is possible.

Detection of pathogenic leptospires in urine from naturally infected cattle by nested PCR

A nested polymerase chain reaction (PCR) using primers from the LipL32 sequence of Leptospira spp. was used to detect shedding of pathogenic leptospires in urine from naturally infected cattle. Amplicons (497bp) were obtained from 21 pathogenic reference serovars belonging to four species (L. interrogans, L. borgpetersenii, L. santarosai, L. kirschneri). DNA was amplified from 26/30 urine samples taken from cattle with suspected leptospirosis and from leptospires cultivated from 10 of these samples. The limit of detection of DNA in the clinical samples was 200pg and the nested PCR detected all pathogenic reference serovars of Leptospira spp. tested. No PCR products were amplified using DNA from other common bacterial species from the bovine urogenital tract or urine, or from the non-pathogenic L. biflexa Andamana serovar. The nested PCR exhibited high specificity and sensitivity for detection of pathogenic serovars in urine from cattle.

Japanese Black Cattle with Orotic Aciduria Detected by Gas-Chromatography/Mass-Spectrometry

A 4-months-old calf of Japanese black cattle was diagnosed with orotic aciduria by gas-chromatography/mass-spectrometry (GC/MS). Until now orotic aciduria had not been reported in Japanese black cattle. The animal showed repeated diarrhea. The hematocrit was low, and microcytes and acanthocytes were observed in blood smears. The calf had lower serum total protein concentrations with a higher blood ammonia concentration. Needle-shaped crystals of orotic acid were observed in urinary sediments. Sequence homologous analysis with cattle uridine monophosphate synthase DNA indicated silent mutation in the affected calf.

Preventive Effect of Mildly Altering Dietary Cation-Anion Difference on Milk Fever in Dairy Cows

In the present study, we examined whether mildly altering dietary cation-anion difference (DCAD) contributes to the prevention of milk fever in dairy cows. Thirty multiparous cows and ten primiparous cows (heifer group) were used in this study and the multiparous cows were randomly divided into three groups of ten animals each (anion, non-anion and control groups). The cows in the anion group were given supplemental salts that slightly lowered DCAD. These salts consisted of 115 g of CaCO3, 42 g of CaHPO4, 65 g of MgSO4 x 7 H2O and 80 g of CaCl2 x 2 H2O as a daily dose for each cow, using a catheter from 21 days before the expected date of parturition until parturition. The cows in the non-anion group were given only the same Ca, Mg and ip supplement but no sulfate and chloride salts as that in the anion group. The cows in the control and heifer groups were not given any additional supplement. The incidence of hypocalcemia in the anion group decreased to approximately half of those in the non-anion and control groups, while the heifer group did not develop hypocalcemia at all. In addition, the number of days spent for the treatment of hypocalcemia and the number of drug bottles (calcium borogluconate solution) used for the treatment decreased to less than half in the anion group compared with those in the non-anion and control groups. At parturition, the serum Ca concentration in the control (6.2 +/- 1.9 mg/dl, mean +/- standard deviation) and non-anion groups (6.4 +/- 1.7 mg/dl) were significantly lower than that in the heifer group (8.3 +/- 0.4 mg/dl), and the level in the anion group was intermediate (7.3 +/- 1.3 mg/dl). The change in ionized Ca concentration was almost the same as that in serum Ca concentration, but only the concentration in the anion group tended to increase slightly from a week before parturition and was significantly higher than that in all other groups three days before parturition. Urinary pH in the anion group was maintained at a mildly acidic level (6.8-7.0) for the last two weeks before parturition, compared with those in the control (7.3-7.5) and non-anion groups (7.9-8.1), and similar to that in the heifer group (6.3-7.3). The urinary Ca excretion was the highest in the anion group among all groups during the prepartum period. There were no specific changes in the excretion of parathyroid hormone and 1,25-dihydroxyvitamin D in all groups of multiparous cows while the levels of these hormones remained low in the heifer group throughout the experimental period. The data in the present study indicates that the administration of anion salts that slightly lowered DCAD in the preparum period was effective for preventing milk fever in multiparous cows. Safe and mild metabolic acidosis induced by the anion salts could be evaluated by urinary pH (6.8-7.0), and might increase the responsiveness to Ca requirement at parturition through some complex mechanisms unrelated to the excretion of Ca-related hormones. In addition, it was clarified that primiparous cows have a high potential to respond to sudden Ca demand unrelated to hormone excretion, and their Ca metabolism was in some respects similar to that in multiparous cows fed anion salts. Therefore, manipulating mildly DCAD is expected to be an effective, safe and natural method for preventing milk fever in dairy cows.

Evaluation of LSSP-PCR for identification of Leptospira spp. in urine samples of cattle with clinical suspicion of leptospirosis

We evaluated the use of low-stringency single specific primer PCR (LSSP-PCR) for genetically typing Leptospira directly from urine samples of cattle with clinical suspicion of leptospirosis. Urine samples obtained from 40 cattle with clinical suspicion of leptospirosis were amplified by specific PCR using the following primers: Internal 1/Internal 2 and G1/G2. The internal primers were designed from the gene sequence of the outer membrane lipoprotein Lip32 from Leptospira kirschneri, strain RM52. The PCR products were amplified with these two pairs of primers, which had approximately 497 and 285bp, respectively, and were subsequently used as a template for LSSP-PCR analysis. The genetic signatures from the leptospires which were present in the urine samples allowed us to make a preliminary identification of the leptospires by comparing the LSSP-PCR profiles obtained directly from urine samples with those from reference leptospires. The LSSP-PCR profiles obtained with the Internal 1 primer or with the G1 primer allowed the grouping of the leptospires into serogroups. LSSP-PCR was found to be a useful and sensitive approach capable of identifying leptospires directly from biological samples without the need for prior bacterial isolation. In conclusion, the LSSP-PCR technique may still be helpful in discriminating serogroups of Leptospira from different animal reservoirs, since the early identification of carrier animals and information on the shedding state are crucial to prevent the spread of leptospiral infection to other animals and humans.

Clinico-pathological findings in cattle exposed to chronic bracken fern toxicity

AIM

To describe changes in blood and urine analytes in a large group of cattle exposed to chronic bracken fern toxicity, in order to identify parameters of potential diagnostic value.

METHODS

The study was conducted on two livestock farms on which bovine enzootic haematuria (BEH) was known to occur; Farm A grazed a local breed of cows and Farm B grazed Friesians. Group A1 comprised 66 cows from Farm A, Group B 54 cows from Farm B, and Group A2 13 heifers from Farm A. Ten healthy cows were used as controls. A complete physical examination was performed (Group A1), and blood (all groups) and urine (Groups A1 and B) samples were collected. Necropsies and histopathology were undertaken on four cows.

RESULTS

Anaemia, leucopenia, monocytosis, thrombocytopenia, hypergammaglobulinaemia, microhaematuria and proteinuria were detected. Multivariate statistical analyses established three phases of the disease of increasing severity; an initial phase, characterised by an extremely high monocytosis and otherwise normal parameters; an intermediate phase, characterised by monocytosis and moderate changes to other analytes; and a final phase, characterised by normal levels of monocytes and many changes to other analytes.

CONCLUSIONS AND CLINICAL RELEVANCE

Monocytosis, detected in 31% of the younger animals, could represent an initial response to consumption of bracken fern and might be useful as an early haematological marker of BEH.

Urinary GGT/creatinine ratio and fractional excretion of electrolytes in diarrhoeic calves

The aim of this study was to monitor renal function in diarrhoeic calves and to determine the effectiveness of an applied fluid therapy. A total of 28 diarrhoeic (n = 18) and healthy (n = 10) Holstein-Friesian calves of different sexes, between 1 and 30 days of age, were used. Blood and urine samples were obtained from diarrhoeic calves before the treatment and then three more times at 24-h intervals during the treatment. From healthy calves, samples were taken only once. Therapy was started by the intravenous administration of 8.4% sodium bicarbonate and 0.9% sodium chloride solutions for the first 24 h, followed by the oral application of a commercial electrolyte solution (sodium chloride 3.5 g, trisodium citrate 2.9 g, potassium chloride 1.5 g and glucose anhydrous 20 g in 1 litre H2O) up to the 48th h of therapy. Before the therapy, the average levels of pH (7.10 +/- 0.12), bicarbonate (HCO3-) (16.48 +/- 3.80 mmol/l), base deficit (-12.65 +/- 5.97 mmo/l) and fractional excretion (FE) of sodium (0.16 +/- 0.11%) and potassium (15.07 +/- 8.56%) were significantly lower while serum urea (17.48 +/- 10.32 mmol/l) and creatinine (Cr) concentrations (169.72 +/- 98.12 micromol/l), haematocrit levels (45.13 +/- 13.60%) and urinary gamma glutamyl transferase (GGT)/Cr ratio (8.6 +/- 4.3 x 1/10(3) U/micromol) were significantly higher in diarrhoeic calves than in healthy calves. Alterations in parameters indicating the presence of renal dysfunction were normalised in the diarrhoeic calves that survived (83.3%). Three calves with severe metabolic acidosis and azotaemia died at the beginning of therapy. It was concluded that the FE of Na and K (FENa, FEK) and urine GGT/Cr ratio may have an important role in assessing renal function in diarrhoeic calves and in evaluating the effectiveness of an applied fluid therapy.

[Stillbirth/perinatal weak calf syndrome in dairy heifers: results of a pilot study]

A pilot study of 10 Dutch dairy herds was performed to investigate possible causes of stillbirth/perinatal weak calf syndrome in heifers. Possible causes and advice for further investigations on farms affected by this syndrome are discussed based on the results of investigations of blood and urine from pregnant young stock, postmortem examination of still-born calves, and a questionnaire held among farmers. Infections with Neospora caninum, Salmonella spp. or Leptospira hardjo, or a deficiency of iodine could be excluded.

Use of pre-partum urine pH to predict the risk of milk fever in dairy cows

The objective of this study was to evaluate the correlation between serum calcium (Ca) and inorganic phosphorus (IP) values and urine pH of cows fed common rations without the addition of anionic salts in late pregnancy. One hundred and seven Holstein cows, having completed two or more lactations and with an expected calving date within the next seven days were selected from two herds. In order to determine levels of serum Ca and IP and urine pH, blood and urine samples were collected seven to one days before parturition. Of the 107 sampled cows, 17 developed recumbency after calving and were considered to be affected by milk fever. There were significant ( p<0.01 ) negative correlations between urine pH and serum Ca, IP and the ratio of Ca to IP, The urine pH, and levels of serum Ca and IP measured within 48 h prior to parturition differed significantly ( p<0.001 ) between recumbent and non-recumbent cows. The sensitivity, specificity, positive and negative predictive values of urine pH test 48 h prior to parturition, using a cut off level of above pH 8.25, were 100%, 81%, 55%, and 100%, respectively. These signify that monitoring urine pH within 48 h prior to parturition is a sensitive method to assess the risk of parturient paresis. The results of this study emphasize the importance of acid-base status of the animal in the pathophysiology of milk fever.

[Methodical influence on selected parameters of the acid-base equilibrium in urine samples from dairy cows]

Estimation of net acid base excretion (NABE) in urine samples of dairy cows has often been reported in the veterinary literature. NABE has been proved to be meaningful in estimation of disturbances in the cows acid base equilibrium. In order to examine the meaningfulness of this method different factors with possible influences on NABE were tested. Estimation of simple and fractionated NABE lead to comparable results. Whereas implementation of fractionated NABE is linked with higher expense, simple NABE gives information at lower expense. After four days storing of urine samples in the refrigerator the concentration of NH4+ increased significantly. In view of using this parameter to estimate the acid metabolic situation this may lead to false information. Therefore urine samples should be examined at least within three days after collecting and refrigerated storing. Sediment distribution significantly influenced all urine parameters. Above all the shift of the values into direction of the reference limit may result in the assessment of individual cows as risk group. Homogeneous mixing of the urine samples must be carried out before NSBA-determination. A higher air portion in the sample containers lead to a significant increase of the pH in urine samples. To prevent influences of the air on urine samples, sample containers should be filled completely.

Use of a monovalent leptospiral vaccine to prevent renal colonization and urinary shedding in cattle exposed to Leptospira borgpetersenii serovar hardjo

OBJECTIVE

To determine whether a monovalent Leptospira borgpetersenii serovar hardjo (type hardjobovis) vaccine commercially available in Australia, New Zealand, Ireland, and the United Kingdom would protect cattle from renal colonization and urinary shedding when exposed to a US strain of Leptospira borgpetersenii serovar hardjo.

ANIMALS

24 Hereford heifers that lacked detectable antibodies against serovar hardjo.

PROCEDURE

Heifers received 2 doses, 4 weeks apart, of the commercial hardjo vaccine (n = 8) or a monovalent US reference hardjo vaccine (8) or were not vaccinated (controls; 8). Heifers were challenged 16 weeks later by intraperitoneal inoculation or conjunctival instillation. Serum antibody titers were measured weekly, and urine samples were examined for leptospires. Heifers were euthanatized 11 to 14 weeks after challenge, and kidney tissue was examined for evidence of colonization.

RESULTS

All 8 heifers vaccinated with the reference vaccine were found to be shedding leptospires in their urine and had evidence of renal colonization. All 4 control heifers challenged by conjunctival instillation and 2 of 4 control heifers challenged by intraperitoneal inoculation shed leptospires in their urine, and all 8 had evidence of renal colonization. In contrast, leptospires were not detected in the urine or tissues of any of the 8 heifers that received the commercial hardjo vaccine. Heifers that received the commercial hardjo vaccine had significantly higher antibody titers than did heifers that received the reference vaccine.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that cattle that received 2 doses of the commercial hardjo vaccine were protected against renal colonization and urinary shedding when challenged with L borgpetersenii serovar hardjo strain 203 four months after vaccination.

Drought associated poisoning of cattle in South Texas by the high quality forage legume Leucaena leucocephala

Approximately 80 head of yearling cattle grazing on 680 acres exhibited signs of Leucaena leucocephala toxicosis, which was confirmed in 3 animals by detection of 3-hydroxy-4 (IH)-pyridone, the metabolite of the poisonous principle mimosine, in their urine. The animals had grazed leucaena almost exclusively due to lack of alternative forage resulting from drought conditions. Toxicosis from this otherwise high quality forage would likely not have occurred had animals consumed lower amounts of leucaena and could probably have been prevented, as it has been elsewhere, had the animals been colonized with Synergistes jonesii, a beneficial ruminal bacterium capable of degrading the toxic metabolites.

Urinary alkaloid excretion as a diagnostic tool for fescue toxicosis in cattle

Fescue toxicosis research studies have often included serum prolactin as a physiologic index of the disorder. Serum prolactin has not been used as a clinical measure of fescue toxicosis because of variation associated with sex and physiologic condition of the animal and climatic and seasonal factors. The primary excretory route of the alkaloids responsible for this toxicosis is the urine. Three pasture experiments were conducted to examine serum prolactin and urinary ergot alkaloid variability among steers continuously grazing endophyte-infected (E+) or endophyte-free (E-) tall fescue and among steers that were switched from one pasture form to the other. A fourth grazing experiment was used to examine how to best to manage the steers prior to sampling for urinary ergot alkaloid excretion. Coefficients of variability for urinary alkaloid excretion were consistently lower (46-65%) than serum prolactin (64-142%). Urinary alkaloid excretion patterns changed within 12 hours following switching steers from E+ to E- pasture or vice versa, but serum prolactin was recalcitrant to change. Because it is less variable and more dynamic than serum prolactin, urinary alkaloid excretion can be used for health assessment of steers grazing E+ and E- pastures. Regression analysis established a quadratic relationship between alkaloid excretion and average daily weight gain, with a regression coefficient of 0.86. Urinary alkaloid analysis was useful in determining whether cattle were consuming toxic tall fescue.

Determination of bovine beta2-microglobulin and albumin in urine by a reversed-phase high-performance liquid chromatography

Reversed-phase high-performance liquid chromatography (HPLC) was used to analyze beta2-microglobulin and albumin in bovine urine. The urine samples were chromatographed on TSK-gel ODS-120T column with an acetonitrile gradient. Urinary beta2-m and albumin were detected at 220 nm. For the pre-treatment, there were two steps proceeding injection: dialysis of urine with distilled water overnight, followed by concentration by solid-phase extraction method using a Sep-Pak cartridge. The retention times of beta2-microglobulin and albumin were 25.35 +/- 0.85 and 32.20 +/- 0.20 minutes (n=5), respectively. The mean analytical recoveries of beta2-microglobulin and albumin added to 0.1 ml of urine samples were 94.5 and 100.5%, respectively. The within-run coefficients of variation ranged from 1.5 to 5.3% for beta2-microglobulin and from 2.3 to 7.0% for albumin. The sensitivity for quantification of each protein was 0.5 microg in 100 microl injected urine samples. Urine samples from healthy cows and from cows with different types of proteinuria were analyzed by this reversed-phase HPLC. Results revealed albumin was remarkable in the urine from a cow with glomerulonephritis, and beta2-microglobulin was, in the urine from a cow with tubular dysfunction.

Hypocalcemia induced by intravenous administration of disodium ethylenediaminotetraacetate and its effects on excretion of calcium in urine of cows fed a high chloride diet

Evidence supports the theory that a diet that is rich in nonmetabolizable anions fed to dairy cows during the dry period reduces the risk of hypocalcemic paresis puerperalis. When cows are fed a diet that is rich in anions instead of cations, more Ca is absorbed in the intestine and excreted in urine. We hypothesized that, in cows fed a diet that was rich in anions, the increased flow of Ca through the body could be drained to support the maintenance of plasma Ca concentration around parturition. The hypothesis was tested by binding plasma Ca through intravenous administration of Na2-EDTA and measuring excretion of Ca in urine. In a 2-period x 14-d crossover study, six, nonpregnant, nonlactating, multiparous cows were fed either a diet that was rich in cations (dietary cation-anion difference = +332 meq/kg of dry matter) or rich in anions (dietary cation-anion difference = -230 meq/kg of dry matter). On the last day of each feeding period, Na2-EDTA was infused intravenously until the amount of plasma Ca that was not bound to EDTA reached approximately 1 mmol/L. The amount of EDTA that could be infused was significantly greater when the cows were fed the diet that was rich in anions. During the infusion of Na2-EDTA the rate of Ca excretion in urine dropped to almost 0 when the diet that was rich in anions was fed. After feeding the diet that was rich in cations, excretion of Ca in urine was negligible and was not reduced further by Na2-EDTA infusion. Thus, in cows fed a diet that was rich in anions, the Ca intended for excretion with urine can be used when plasma Ca is under stress as would occur at the onset of lactation. However, the amount of Ca derived from plasma, interstitial fluid, and the skeleton during Na2-EDTA infusion was quantitatively much more important to the supply of Ca than was the reduction in excretion of Ca in urine. Most likely, this relationship would also be true when the production of colostrum begins.

[Determination of bone markers in dairy cows with parturient paresis]

The collagen metabolites hydroxyproline (HYP), deoxypyridinoline (DPD) and pyridinoline (PYD) are suitable markers for bone resorption in humans and several animal species. In a field trial cows with symptoms of periparturient paresis (group A) and healthy control cows without symptoms (group B) were compared and urine and blood samples were collected on day 1, 2, 3, 4, 5, 9 and 14 after parturition. In group A the mean +/- SE serum Ca concentration on day 1 was 1.4 +/- 0.1 mmol/l whereas those of group B were 2.0 +/- 0.1 mmol/l. A significant increase of the corrected urinary HYP concentration was observed from parturition to day 14 (from 2.8 to 8.8 mumol/mmol creatinine) and the concentrations at the different times were higher in group A than in group B. The mean corrected total and free DPD and total PYD concentration in urine increased after parturition to reach a peak at day 9. For DPD and PYD the mean concentrations between the two groups did not differ significantly. The DPD and PYD are useful tools to follow bone resorption in dairy cows, although in our study no difference between the two groups could be found which means that both groups were able to mobilize Ca from bone.

Comparison of disease in calves dosed orally with oak or commercial tannic acid

Commercial tannic acid has been used as a substitute for leaves and acorns in studies of oak toxicosis in some species. The toxicity of a commercial tannic acid given orally to calves was determined, and the clinical signs, laboratory findings, and pyrogallol production were compared with those found in calves dosed orally with oak leaves. The oak-fed calves developed the clinical signs and lesions characteristic of renal failure. Proteinuria developed by 48 hours in 1 calf and by 72 hours in the other calf. Both calves developed hematuria on day 4 and glucosuria on day 5. The blood urea nitrogen and creatinine values increased markedly on day 6. Pyrogallol was detected in the serum only at 3 and 6 hours after the calves began ingesting the oak leaves. Pyrogallol was detected in urine from 1 calf until 60 hours and in the other calf until 48 hours after the beginning of oak intake. The 2 calves that were dosed with tannic acid at the same level as found in the leaves fed to the other calves did not develop clinical signs, abnormal laboratory findings, or pyrogallol production. Calves given high levels of tannic acid at doses of 4.4-5.5 g/kg developed methemoglobinemia rather than renal disease. Therefore, commercial tannic acid given orally cannot be used as a substitute for oak in studies of toxicosis in cattle.

[Investigations on the development of hyponatremia in older calves with diarrhea]

The study involved 50 hospitalized calves (four weeks to five months old) suffering from diarrhoea and hyponatraemia (blood sodium concentration below 130 mmol/l). Starting from the day of admission blood, urine, and faecal samples were taken each morning and sodium and potassium concentrations were measured. In addition, blood and urine samples were taken in the evenings, if electrolytes had been given orally during the day. The obtained values from urine samples were compared with the plasma concentrations in order to check for inadequate renal excretion of electrolytes. Consistency of the faeces and visible blood admixture were the main criteria in the evaluation of electrolyte concentration in the 317 samples of faecal water. With one exception no inadequate renal losses of sodium were observed. Sodium and potassium concentrations in faecal water showed a distinct negative correlation. As the consistency of faeces grew increasingly normal, electrolyte contents of faeces approached those reported for adult cattle, i.e. potassium levels rose and sodium levels decreased. Visible blood admixtures had no significant effect on the sodium and potassium concentrations in the faeces. A distinct relationship between electrolyte contents in faecal water and the consistency of the faeces was found. There were highly significant differences in electrolyte concentrations between faeces of watery (Na: 82 +/- 21 mmol/l; K: 23 +/- 12 mmol/l) and soupy (Na: 54 +/- 26 mmol/l; K: 42 +/- 19 mmol/l) consistency (mean +/- standard deviation). By contrast, soupy and pulpy faeces just showed a slight or no difference in electrolyte concentrations. Only faeces of watery consistency contained approximately as much sodium as observed in neonatal calf diarrhoea. These results show that the pronounced hyponatraemia in older calves can hardly be attributed to loss of sodium via faeces and urine. The following possible causes are proposed: (a) older calves usually have access to water (therefore there is more gradual dehydration or no dehydration at all); (b) oral electrolyte solutions are seldom administered.

Development of an immunomagnetic antigen capture system for detecting leptospires in bovine urine

A magnetic bead antigen capture system which combined the use of two evolving techniques - immunomagnetic separation (IMS) and time-resolved fluoroimmunoassay (TR-FIA) - was developed to detect Leptospira borgpetersenii serovar hardjo in bovine urine. The assay utilised monoclonal antibody coated magnetic beads to capture leptospiral antigen which was in turn detected using another monoclonal antibody (Indicator) labelled with biotin. Signal was generated by the binding of europium labelled streptavidin to indicator antibody. The sensitivity of the assay was improved from 10(3) to 10(2) leptospires per ml by using an ethanol precipitation procedure to treat each sample. The assay detected only 31 of 56 (55 per cent) urine specimens culture-positive for hardjo, but seven of 24 urine samples culture-negative for hardjo were identified as positive by the assay. These seven samples were from animals which were culture positive on at least one other occasion. These results suggest that this system should be further investigated as a complementary test to culture for the identification of hardjo carrier animals.

Urine N-acetyl-beta-D-glucosaminidase activity in healthy cattle

OBJECTIVE

To measure urine N-acetyl-beta-D-glucosaminidase (NAG) activity of healthy cattle, using 3 substrates (4-methylumbelliferyl-N-acetyl-beta-D-glucosaminide, sodio-m-cresolsulfonphthaleinyl-N-acetyl-beta-D-glucosaminid e, and p-nitrophenyl-N-acetyl-beta-D-glucosaminide), and to determine the relations between the obtained values and age and sex of cattle.

ANIMALS

50 healthy lactating Holstein-Friesian cows and 10 healthy Holstein-Friesian steers.

PROCEDURE

Untimed urine samples were collected, and urine NAG activity was measured, using the 3 aforementioned methods. Urine creatinine concentration also was measured, and NAG activity was expressed as units per gram of creatinine (NAG index). Correlations between urine NAG activity and age and sex of cattle were investigated. Furthermore, correlations among data obtained by each of the 3 methods were determined.

RESULTS

Urine NAG activity in cows measured by each of the 3 methods was < 3.0 U/L. Urine NAG activity in steers was significantly higher than that in cows. However, there was no significant difference between the sexes in NAG index. There were no significant differences in mean values of NAG activity and index among cows of various age groups. Individual values of urine NAG activity determined by each method correlated significantly with each other.

CONCLUSIONS AND CLINICAL RELEVANCE

Urine NAG activity and NAG index of healthy cattle will be useful for determining diagnostic criteria of renal disease in cattle.

Urinary diagnostic indices in calves

OBJECTIVE

To establish reference values for urinary diagnostic indices in healthy calves from birth to 90 days of age.

DESIGN

Prospective field trial.

ANIMALS

12 Holstein heifer calves.

PROCEDURE

Urine and serum samples were collected daily for the first 5 days after birth, then weekly until calves were 90 days old. Urine:serum creatinine ratio, urine:serum urea nitrogen ratio, urine:serum osmolality ratio, fractional clearances of sodium and inorganic phosphate, and urine gamma-glutamyltransferase activity were measured. Data were grouped by age of calves at the time of sample collection: 1 to 5 days old (neonatal period), 7 to 27 days old (suckling period), and 28 to 90 days old (weanling period).

RESULTS

Mean urine:serum creatinine, urea nitrogen, and osmolality ratios were significantly higher during the weanling period than during the other 2 periods. There were no significant differences in mean fractional clearances of sodium among age periods.

CLINICAL IMPLICATIONS

Urinary diagnostic indices calculated for these healthy calves may be used as reference values for early recognition of renal damage or renal failure.

Rapid and specific detection of pathogenic Leptospira species by amplification of ribosomal sequences

We have developed an assay for the detection of pathogenic Leptospira that is based on the polymerase chain reaction. With the combination of agarose gel electrophoresis and blotting, pathogenic Leptospira can be discriminated specifically from nonpathogenic Leptospira and other bacterial species. This method, based on the amplification of 16S ribosomal RNA sequences, is able to detect 10 leptospiral cells/mL in cattle urine samples and 100 leptospiral cells/mL in pig urine samples. Using this assay leptospires were detected in urine samples from cattle that were experimentally infected with Leptospira interrogans serovar hardjo type hardjobovis.

Evaluation of two cowside tests for the detection of subclinical ketosis in dairy cows

The goal of this study was to evaluate the sensitivity and specificity of two cowside tests for subclinical ketosis in dairy cows. The tests utilize milk and urine samples, respectively. One hundred and eighty-five cows, one to sixty days postpartum, were sampled for milk, urine, and blood. Subclinical ketosis was defined with serum beta-hydroxybutyrate measurements. The sensitivity and the specificity of both tests at different beta-hydroxybutyrate levels were estimated. When subclinical ketosis was defined at beta-hydroxybutyrate levels of 1.4 mmol/L and higher, the milk test had sensitivity of 90% and specificity of 96%. The urine test lacked specificity (values < 67%), but sensitivity was 100% at beta-hydroxybutyrate levels of 1.4 mmol/L upward. Both the milk and urine test can be used to monitor subclinical ketosis in a herd. Milk testing is preferred, because of the easy obtainability of milk combined with the overall better test characteristics.

[The pre- and postoperative course of pH values and net acid-base excretion in the urine of cows with abomasal displacement]

The pre- and postoperative course of acid-base parameters and electrolyte concentrations in urine and blood was studied in 67 cows affected with left- or right-sided abomasal displacement. Paradoxic aciduria was detected in 21 of 37 cattle with preoperative alkalosis. The validity of serum electrolyte determinations for the detection of electrolyte disturbances is limited. The evaluated parameters returned to normal in most of the animals within the following intervals post-op.: 1 day: blood gas parameters 2 days: hematocrit; 3 days: general condition, serum chloride and serum sodium concentrations; 4 days: urine-pH, net acid-base excretion, urine chloride and serum potassium concentrations; Urine-pH and net acid-base excretion increase only after serum electrolyte levels return to normal.

Experimental systemic bovine zygomycosis with reference to pathology and secretion of antigen into urine

ELISA and immunoblotting were applied for the characterization of somatic antigens from Absidia corymbifera. Immunoblotting revealed major antigenic bands at 11 to 81 kDa. The ELISA showed some crossreactivity towards somatic antigens from other fungi. However, the crossreactivity was especially observed with somatic antigens from other fungi of the zygomycetes. The ELISA and immunoblotting assays were applied to urine samples from two groups of 3 calves each systemically infected with A. corymbifera and Aspergillus fumigatus, respectively. The immunoreactivity of the urine samples was similar by the two assays. Somatic antigens were demonstrated in the urine of all three calves infected with A.corymbifera, whereas only one of the calves with systemic aspergillosis was antigen positive. The level of antigen in the positive urine samples varied from 50 to 210 ng/ml.

Urinary protein analysis in cardiomyopathy-affected and healthy cattle by SDS-polyacrylamide gel electrophoresis

Urinary proteins of cardiomyopathy (CMP)-affected (n = 31) and of healthy cattle (n = 35) were analyzed by a combination of SDS-polyacrylamide gel electrophoresis and silver stain. The following results were obtained: 1) Out of the various urinary proteins found in CMP-affected and healthy cattle, IgG, Tf, Alb, alpha 1-acid GP, Apo A1, IgG heavy and light chain could be identified. 2) In CMP-affected cattle, all the proteins mentioned above were detected in increased amounts in the urine. The quantities of Alb, Tf, and IgG were especially large. 3) In the case of CMP, the permeability of the glomerular filter was highly increased for large serum proteins. The tubular protein reabsorption of small proteins was less altered by the disease. 4) Although the electrophoretic pattern of the urinary proteins was abnormal in all the examined CMP-affected animals, the urinary protein concentrations were increased (> 230 mg/l) in only 42% of the cases. Consequently, the urinary protein concentration is not a reliable parameter for detecting renal diseases. 5) For both CMP-affected and healthy cattle the urinary protein pattern depended neither on the urine sampling technique (catheterization, spontaneous urine) nor on the reproductive stage.

Duration of urinary excretion of leptospires by cattle naturally or experimentally infected with Leptospira interrogans serovar hardjo

The excretion of Leptospira interrogans serovar hardjo in the urine of cattle was studied in naturally and experimentally infected animals. Five of 15 naturally infected animals with microscopic agglutination test titres of > or = 1:300 shed leptospires for between 28 and 40 weeks. Twenty yearling heifers, experimentally infected by either the supraconjunctival or intrauterine routes, shed leptospires for from eight to 60 weeks; the 10 infected via the uterus shed L interrogans serovar hardjo for a mean of 26 weeks (range eight to 54 weeks) and the 10 infected by the supraconjunctival route shed the organism for a mean of 32 weeks (range 12 to 60 weeks). The results suggest that natural infection results in more prolonged excretion than experimental infection. No intermittent or seasonal excretion of the organism was observed. After the initial experimental infection, large numbers of leptospires were shed in the urine for several weeks, and thereafter there was a progressive decline in the number of organisms shed.

The effects of hypocalcaemia due to a 4-hour infusion of Na2EDTA solution on various blood and urine analytes in dairy cows and a comparison of these effects between cows with high and low erythrocyte potassium concentrations

Six HK (high erythrocyte potassium) and 7 LK (low erythrocyte potassium) dairy cows were subjected to a 4-h intravenous infusion of 4.7% Na2EDTA solution to induce and maintain hypocalcaemia. Blood samples taken immediately before infusion, hourly for 7 h, and at 24 h after commencement of infusion were subjected to determination of concentration (or count) of 16 analytes. The mean changes in concentrations (or counts) of the various blood analytes were calculated for the periods 0-4, 4-7, 7-24, and 0-24 h after commencement of the infusion for all cows combined, and then separately for the HK and LK groups of cows. Plasma Ca(PCa), plasma inorganic phosphorus (PiP) and plasma potassium (PK) showed significant decreases during the 4-h infusion period and were still below pretreatment levels 24 h later. AST, CPK, PCVs and white cell-counts (WCCs) showed significant early increases which were still significantly elevated 24 h later. Plasma magnesium (PMg) and erythrocyte Na(ENa) and K(EK) all showed delayed changes which still persisted 24 h later. Significant between-group differences were present for PCVs which increased significantly more in the LK than the HK group during the infusion period, for PCa which showed a greater increase in the HK cows than the LK cows during the 4-7 h early clinical recovery period, and for plasma bilirubin (PBil) which showed a greater increase from 0 to 24 h in the HK group than in the LK group. Urine samples, collected before infusion, 4-7 h and 24 h after commencement of the infusion, were subjected to analysis for glucose, protein, pH, 'blood' and ketones. Most cows showed increases in urinary glucose, protein and 'blood'.

[Hematologic and clinico-chemical research findings in calves and young cattle with ileus]

The impairment of fluid, electrolyte and acid-base status which is observed in calves and juvenile cattle as a result of ileus and subileus is not only dependent on form and site of the obstruction, but is also influenced considerably by the duration of the condition and any coexisting disease. This publication reviews the most important blood, urine and ruminal fluid parameters in such patients. The diagnostic significance of the laboratory values under discussion is not so great with obstructions to the caudal part of the digestive tract. However, markedly raised ruminal fluid chloride levels, combined with hypochloraemia and a metabolic acidosis, are indicative of an "abomasoruminal reflux syndrome" resulting from an obstruction in the region of the abomasum or cranial small intestine.

Isolation and purification of a low molecular weight protein from bovine urine

A low molecular weight protein was separated from urine samples obtained from a heifer with spontaneous renal disease and from cows with CaNa2EDTA-induced renal dysfunction. The molecular weight and electrophoretic mobility of the separated protein were examined. The low molecular weight protein collected by gel filtration chromatography was further separated into two fractions by ion exchange chromatography using DEAE-cellulose. One of the two fractions, the lowest molecular weight protein showed a single band in SDS-PAGE, and its molecular weight was approximately 12,000. An antiserum against this protein formed a single precipitin line with the urine from cows with experimentally induced renal dysfunction and a heifer with spontaneous renal disease by the double immunodiffusion technique. However, the antiserum did not form any precipitin line with the concentrated urine of healthy cow and human beta 2-microglobulin. In cellulose acetate membrane electrophoresis, this protein migrated in the same position as that of serum gamma-globulin from healthy cow.

Diagnosis of nitrate toxicosis in cattle, using biological fluids and a rapid ion chromatographic method

An ion chromatographic method was used to simultaneously determine nitrate and nitrite ions in biological samples. Ultrafiltration was used to produce a protein-free filtrate. Chloride interferences were eliminated by precipitation as the silver salt. Detection limits and average recoveries were 0.5 mg/L and 102% for nitrate and 0.2 mg/L and 78% for nitrite, respectively. Nitrate concentration was 2.1 +/- 1.8 mg/L and 4.9 +/- 0.8 mg/L in serum and ocular fluid of healthy cattle, respectively; nitrite was not detected. A severe case of nitrate poisoning in cattle was described and used to study the concentrations of nitrate and nitrite in samples obtained under natural conditions. Nitrate concentration of acutely poisoned cattle was 35% lower in ocular fluid at 158.1 +/- 51.4 mg/L, than in serum at 256.3 +/- 113.4 mg/L. Nitrite was not detected, because of the long processing time (greater than 3 hours) required for samples obtained in the field. A gradual decrease in ocular fluid nitrate of 29.4% at 24 hours, 25.9% at 36 hours, 51.6% at 48 hours, and 73.2% at 60 hours was observed; however, concentrations remained diagnostically significant (73.2 mg/L) 60 hours after death. Twenty-four hours after poisoning, the serum nitrate concentration of severely ill (52.7 +/- 51.9 mg/L) and moderately affected (12.4 +/- 5.7 mg/L) cattle that survived was indicative of the severity of clinical signs previously observed. Nitrate in serum and ocular fluid was stable in samples stored for 24 hours at 23 C, 1 week at 4 C, and 1 month at -20 C.

[Use of urinary furazolidone determination in calves in laboratory diagnosis]

We examined 41 samples of calf urine in order to determine the urinary furazolidone excretion. 26 calves were administered furazolidone in the form of Terapeutan T in a therapeutic dose of 5 kg per os individually, which represents approx. 3 mg of furazolidone per kg body weight per day over 5 days. 11 calves were administered with twice the therapeutic dose, i.e. 6 mg furazolidone per kg live body weight over the same 5 days. A triple strength dose was administered to two calves on the 2nd and 3rd days and after administration we observed the furazolidone excretion in urine. The dynamics of furazolidone excretion in urine of one calf we determined even after the fivefold dose in comparison with the therapeutic dose, administered in the course of 2 days after application of the double dose, which was administered over 4 days. During administration of 3 mg and 6 mg furazolidone respectively per kg of live weight per kg furazolidone was excreted in urine minimally and only rarely (7.6%). During administration of higher doses furazolidone was found in the urine of all individuals. The highest urinary concentration of furazolidone in calves was determined after administration of the fivefold dose in comparison with the therapeutic dose, i.e. 15 mg furazolidone per kg live weight in the 4th hour after urine collection (23.0 mg furazolidone per liter urine). When this dose was administered over 2 days, it did not effect any clinical symptoms of disease. It has proved to be well founded to determine the furazolidone level in calf urine in laboratory diagnostics. The examination contributes to the estimation of the furazolidone dose, administered to calves. Urinary furazolidone concentrations greater than 1.0 mg.l-1 provide warning signals of overdosage with this chemotherapeutic. For urine furazolidone determination we utilized the photometric method, described by Herret and Buzard (1960).

Detection of leptospires in urine by polymerase chain reaction

Primers for polymerase chain reaction (PCR) were synthesized from clones derived from a Leptospira hardjo (type hardjobovis) library. One pair of synthetic oligonucleotide primers was selected for further analysis. Under experimental conditions an amplification was obtained with DNA of Leptospira interrogans of some serovars belonging to serogroup sejroe. However, very little or no amplification was observed with DNA from other serovars of this group. No amplification was observed with DNA from other serogroups, other bacteria, or eucaryotic organisms. Cattle urine, seeded with hardjobovis, was processed in several ways and subsequently subjected to PCR. Boiling of the samples or treatment with detergents appeared to be most effective. Urine samples containing fewer than 10 leptospires gave a positive result in the PCR assay. Twenty urine samples obtained from a slaughterhouse or farm cows were investigated using the PCR assay, culture isolation, dot and quick blot hybridization, and serological tests. This comparative study suggests that amplification by PCR may be a valuable method for the detection of leptospires in cattle urine.

Udder edema in cattle: effects of diuretics (furosemide, hydrochlorothiazide, acetazolamide, and 50% dextrose) on serum and urine electrolytes

Blood and urine chemical values at parturition in clinically normal Holstein cows (n = 12) were compared with the same values in Holstein cows developing udder edema (n = 12). There was no statistically significant mean difference between the 2 groups for the serum and urine chemical data. Furosemide (500 mg) given IV caused a significant increase in serum calcium and sodium, urine chloride, potassium, and sodium, and fractional excretional ratio of chloride, potassium, and sodium. There was a significant mean decrease in the serum potassium, urine creatinine, osmolality, pH, and specific gravity. Hydrochlorothiazide (250 mg) given IV caused a significant mean increase in serum chloride, urine chloride, potassium, and sodium, and fractional excretion ratio of chloride, potassium, and sodium. There was a significant mean decrease in serum potassium and sodium, urine osmolality, pH, and specific gravity. Acetazolamide (500 mg) given IV caused a significant mean increase in blood urea nitrogen, serum chloride and glucose, urine sodium, and fractional excretion ratio of sodium, while causing a significant mean decrease in serum potassium, sodium, and phosphorus, and urine creatinine. Dextrose (500 g) given IV as a 50% solution caused a statistical mean increase in serum glucose, urine chloride, potassium, and sodium, and fractional excretion ratio of chloride and potassium. A statistical mean decrease occurred in the packed cell volume, blood urea nitrogen, serum calcium, potassium, sodium, and phosphorus, urine creatinine, osmolality, and pH.

Repetitive sequence element cloned from Leptospira interrogans serovar hardjo type hardjo-bovis provides a sensitive diagnostic probe for bovine leptospirosis

A repetitive sequence element was cloned from the primary etiological agent causing bovine leptospirosis in North America, Leptospira interrogans serovar hardjo type hardjo-bovis. This element was used to design a sensitive diagnostic probe which distinguishes hardjo-bovis from other pathogenic leptospires which commonly infect domestic animals in North America and discriminates between hardjo-bovis and the reference strain for serovar hardjo, hardjoprajitno. By using this probe, it was possible to identify infected cattle shedding hardjo-bovis in their urine. This is the first practical demonstration of a cloned DNA probe for leptospirosis, and it provides a sensitive method for studying the transmission and pathogenesis of L. interrogans infections. Control measures for L. interrogans infections may now be improved by rapidly and efficiently identifying infected animals.

Urethral extension for correction of urovagina in cattle. A review of 14 cases

Urethral extension was performed in 14 cows with clinical urovagina and infertility. Urovagina was corrected in nine cows (64%) and was reduced in the others. Formation of fistulas at the cranial end of the extension site was the most frequent complication (4 cows). In one cow, the urethral extension was not extended far enough caudally. Eleven cows (79%) returned to fertility after surgery. Severity of urine pooling, cranial displacement of the urethral orifice, and severe preoperative vaginitis may explain the failure of the urethral extension in some cows.