Hollis N. Erb

Epidemiology of reproductive disorders in dairy cattle: associations among host characteristics, disease and production

Logistic regression was used to investigate the effects of host characteristics, production and 23 veterinary diagnoses on the risks of 10 reproductive disorders. For each reproductive disease in each lactation record, all prior disease events in that lactation were examined as possible risk factors. To make an equal opportunity for risk-factor diseases to be counted as present in both cases and controls, a dummy days in milk (DIM) variable was assigned to control records. The assignment was random, but in proportion to the distribution of the DIM for the cases of that disease. The data set was based on 61 124 Finnish Ayrshire cows, from milk-recorded herds, who calved during 1983. Each cow was under observation for 2 days before calving to the following calving or to removal from the herd. Twenty percent of the cows were treated by a veterinarian for reproductive disorders. Lactational incidence rates (%) were: dystocia, 1.2; prolapsed uterus, 0.2; retained placenta, 4.4; early metritis, 2.3; silent heat, 4.9; cystic ovary, 6.8; prolapsed vagina, 0.1; late metritis, 1.1; other infertility, 2.1; abortion, 0.4. The risk of silent heat and other infertility decreased and the risk of dystocia (after the first calving), retained placenta and ovarian cyst increased with increased parity. Parity did not explain the incidences of the other reproductive disorders. The cows calving during September-February (the dark season) had higher risks of early metritis, silent heat, cyst and other infertility than those calving during the light season. Higher herd milk yield in the previous lactation increased the risks of retained placenta, early metritis and late metritis; higher herd yield in the current lactation increased risks of dystocia and of ovarian cyst. The risks of retained placenta, early metritis, silent heat, ovarian cyst, other fertility and abortion also increased with increased individual-cows milk yield. Most reproductive disorders were interrelated. Six non-reproductive disorders (non-parturient paresis, udder edema, indoor and outdoor hypomagnesemia, rumen acidosis and chronic mastitis) were not risk factors for any of the reproductive disorders. Of the other non-reproductive disorders, clinical parturient paresis was a risk factor for dystocia, prolapsed uterus, retained placenta, and early metritis; clinical ketosis was associated with silent heat, cystic ovary and other infertility; disorder of the abomasum, traumatic recticuloperitonitis, acute mastitis and foot or leg injury also contribited to early metritis. No disorders were protective.

Recurrent airway obstruction (RAO) in horses is characterized by IFN-γ and IL-8 production in bronchoalveolar lavage cells

In horses prone to developing recurrent airway obstruction (RAO), we tested the hypotheses that the cytokine profile in the bronchoalveolar lavage (BAL) cells of affected horses would reflect a polarized Th-2 response; that cytokine and chemokine alterations would occur within 24 h of allergen exposure; and that allergen exposure would induce alterations in the expression of the transcription factor t-bet (t-box-expressed in T-cells). The expression levels of interleukin-4 (IL-4), IL-13, Interferon-gamma (IFN-gamma), t-bet, IL-8 and granulocyte-macrophage colony stimulating factor (GM-CSF) were measured in BAL cells obtained from control and RAO-susceptible horses during an asymptomatic phase and at 24 h and 5 weeks post-stabling and hay exposure. At each sampling time, BAL neutrophil percentages in the RAO-group exceeded controls. In the RAO-group, only IL-13 expression was decreased 2-fold during the asymptomatic phase. No differences in cytokine or chemokine expression were detected during the acute exposure phase. During the chronic phase, IFN-gamma and IL-8 expression levels were 2.5- and 3-fold greater, respectively, in the RAO-group. No other differences in gene expression were detected. We conclude that the cytokine profile of the airway cells does not reflect a polarized Th-2 response; that increases in IFN-gamma result from a t-bet independent pathway and that chemokines from epithelial or interstitial cells may contribute to early neutrophil influx.

Plasma adrenocorticotropin (ACTH) concentrations and clinical response in horses treated for equine Cushing's disease with cyproheptadine or pergolide

Plasma ACTH levels have been variable in horses with a positive clinical response for therapy for equine Cushings Disease (ECD). Therefore, our purpose was to determine the value of monitoring plasma adrenocorticotropin (ACTH) levels during treatment of equine Cushings disease (ECD) with either cyproheptadine (n = 32) or pergolide (n = 10). First, we validated the chemiluminescent ACTH assay (specificity, precision, accuracy, intra-assay and interassay variations) and tested methods of handling the whole blood from the time of collection to when the ACTH was assayed. The sensitivity and specificity of high plasma ACTH levels for detecting ECD was determined in a retrospective study on hospitalised horses (n = 68). Surveys were sent to veterinarians who submitted equine ACTH levels that were high initially and had at least 2 ACTH samples to determine the value of monitoring ACTH levels during therapy of ECD. The ACTH chemiluminescent assay was valid. The ACTH was stable when whole blood was collected and held in plastic tubes for 8 h before separating the plasma. The sensitivity and specificity of plasma ACTH levels for detecting ECD were 84% (n = 19,95% CI 60,97) and 78% (n = 49,95% CI 63,88), respectively. Treated horses generally showed a decrease in plasma ACTH. Plasma ACTH levels may be helpful when monitoring therapy of ECD, although improvement in clinical signs should be considered most important. There were no differences between cyproheptadine and pergolide in terms of improvements in any of the clinical signs.

The Effect of Calfhood Diseases on Growth of Female Dairy Calves During the First 3 Months of Life in New York State

Abstract Our objective was to study the effects of pneumonia (cumulative incidence, 25%), diarrhea (29%), umbilical infection (14%), and umbilical hernia (15%) on BW and height gains during the first 3 mo of life. Female dairy calves (n = 410) born from January to December 1990 in 18 commercial herds in New York state were used. Average daily gains during the 1st, 2nd, and 3rd mo were 374, 596, and 719g, respectively; average gain was 565g during the 3-mo period. Average monthly height gains during the 1st, 2nd, and 3rd mo were 4.4, 5.6, and 5.7cm, respectively. Use of multiple linear regression, with farms treated as random effects, indicated that treated, verified pneumonia was associated with a reduction in average daily gain of 66g and that failure of passive transfer reduced average daily gain by 48g during the 1st mo. During the 2nd mo, neither disease nor failure of passive transfer affected average daily gain. During the 3rd mo, each additional week of pneumonia reduced average daily gain by 14g, and umbilical infection reduced average daily gain by 96g. Each additional week of diagnosed pneumonia reduced total BW gain during the first 3 mo by 0.8kg. Similarly, each week of pneumonia reduced total height gain by 0.2cm and failure of passive transfer by 0.9cm. Prevention of chronic pneumonia and umbilical infection may improve average daily gain of calves.

The effect of maternally derived immunoglobulin G on the risk of respiratory disease in heifers during the first 3 months of life

The objectives were to investigate the association between postcolostral serum IgG and the development of calf pneumonia, to elaborate the risk factors for pneumonia, and to compare the risk factors for clinician- and caregiver-diagnosed respiratory disease. In a prospective observational cohort study, 410 heifer calves were clinically examined weekly by a veterinarian during their first 3 months of life. With an initial questionnaire and during these weekly visits, management data were collected. A nested matched case-control design was used to compare risk factors between 105 calves with respiratory disease and their 59 control calves from the same initial population. The IgG levels were determined from blood samples taken within 2 weeks after colostrum intake. The appropriate cutoff point for the postcolostral IgG level to indicate failure of passive antibody transfer when predicting pneumonia appeared to be between 800 and 1300 mg/dl (values < or = the cutoff point indicated failure). Calves with low IgG levels had 2-times higher odds of pneumonia than calves with higher IgG concentrations. Housing mostly in the presence of adult cattle was a risk factor for pneumonia, whereas housing mostly alone in a hutch was protective. Feeding of mastitic colostrum was a risk factor for clinician-diagnosed pneumonia in the analysis of the cohort study but not in the matched case-control design. There was a three-times higher risk of pneumonia if calves were given their dams colostrum for the first feeding and the dam had clinical mastitis at the time of first milking. Caregiver- and clinician-diagnosed pneumonia had slightly different risk factors which implies that caution should be used when comparing studies based on different definitions of pneumonia. The practical implications of this study are that more attention should be paid to proper housing conditions of the calves in order to reduce incidence of pneumonia.

Urinary tract infections in cats with hyperthyroidism, diabetes mellitus and chronic kidney disease

The prevalence of urinary tract infections (UTIs) in cats with hyperthyroidism (n=90), diabetes mellitus (DM) (n=57) and chronic kidney disease (CKD) (n=77) was evaluated retrospectively. It was found to be 12% in cats with hyperthyroidism and DM, respectively, and 22% in cats with CKD. Associations between UTIs and clinical signs, biochemical markers in serum and urinalyses were investigated. Many of the cats with UTIs had no clinical signs of lower urinary tract disease or changes in their laboratory values indicative of infection. Therefore, a urinalysis alone should not be used to exclude UTIs in these cats. UTIs are relatively common in cats with hyperthyroidism, DM and CKD, and urine cultures are recommended as part of the basic diagnostic plan for cats suspected of suffering from these conditions.

Outcome of cats with low-grade lymphocytic lymphoma: 41 cases (1995-2005).

OBJECTIVE To evaluate factors associated with response to treatment, remission duration, and survival in cats with low-grade lymphoma affecting various organ systems. DESIGN Retrospective case series. SAMPLE POPULATION 41 cats with histologically confirmed low-grade lymphocytic lymphoma. PROCEDURES Medical records and biopsy specimens of cats with histologically confirmed low-grade lymphocytic lymphoma of various organ systems treated with prednisone and chlorambucil between 1995 and 2005 were reviewed. The Kaplan-Meier method was used to estimate remission duration and survival. Factors potentially associated with prognosis were compared. RESULTS Common clinical signs were weight loss (83%), vomiting (73%), anorexia (66%), and diarrhea (58%). Seventy-eight percent of cats tested had low serum cobalamin concentrations. Lymphoma was confined to the gastrointestinal tract in 68% of cats. Fifty-six percent of cats achieved a complete response to treatment, and 39% achieved a partial response. Five percent of cats had no response. No association was found between any risk factors (including anatomic site) and response to treatment. Partial response was associated with shorter remission duration, compared with complete response; median remission duration was 428 days for cats achieving a partial response, compared with 897 days for cats achieving a complete response. No other factors were associated with remission duration. Overall median survival time was 704 days. No factors were significantly associated with survival time. CONCLUSIONS AND CLINICAL RELEVANCE Most cats with lymphocytic lymphoma responded to treatment with prednisone and chlorambucil, and most factors evaluated were not associated with outcome.

Distribution of a lidocaine-methylene blue solution staining in brachial plexus, lumbar plexus and sciatic nerve blocks in the dog

OBJECTIVE To determine the influence on the distribution of the volume of a local anaesthetic-methylene blue solution at three different nerve block sites in the dog. STUDY DESIGN Randomized, controlled, blinded experimental trial. ANIMALS 23 hound-cross dogs weighing 16-40 kg and aged 2 +/- 0 years (mean +/- SD). METHODS Dogs were anaesthetized and randomly assigned to three groups of seven or eight dogs each, based on volume administered: low, medium and high volume (L, M and H). Using electrolocation, the injection was performed after a positive response was elicited (flexion of the elbow for the brachial plexus block, quadriceps contractions for the lumbar plexus and dorsiflexion/plantar extension of the foot for the sciatic nerve block). At the brachial plexus site, groups L, M and H received 0.075, 0.15 and 0.3 mL kg(-1), respectively. At the lumbar plexus site, groups L, M and H received 0.1, 0.2 and 0.4 mL kg(-1), respectively. At the proximal sciatic nerve site, groups L, M and H received 0.05, 0.1 and 0.25 mL kg(-1), respectively. Necropsies were performed immediately following euthanasia. Staining of > or =2 cm along the nerve was considered sufficient; the proportions sufficient were compared with Fishers exact test. The volume was recommended when all the relevant nerves were stained sufficiently in all or all but one of the dogs within the group. RESULTS In the brachial plexus, only in group H were all the nerves stained sufficiently. In the lumbar plexus site, no statistical difference was found, but we suggest the H group volume to balance sufficient and excessive staining. At the sciatic nerve site, all volumes tested produced sufficient staining in all (or all but one) dogs. CONCLUSIONS AND CLINICAL RELEVANCE Volumes of 0.3 and 0.05 mL kg(-1) produced sufficient distribution for performing brachial plexus, and sciatic nerve blocks, respectively. Additionally, a volume of 0.4 mL kg(-1) might also be adequate for a lumbar plexus block (no statistical significance was reached).

Investigations into the role of the thyrohyoid muscles in the pathogenesis of dorsal displacement of the soft palate in horses

REASONS FOR PERFORMING STUDY Contributes to the understanding of the pathogenesis of dorsal displacement of the soft palate during exercise so that management of this condition could be enhanced. HYPOTHESIS That the thyrohyoid muscles play an important role in the stability of the laryngo-palatal relationship and that dysfunction of these muscles leads to dorsal displacement of the soft palate (DDSP) during exercise. METHODS Ten horses were exercised on a high-speed treadmill under 4 different treatment conditions: control conditions (n = 10), after resection of thyrohyoid muscles (TH, n = 10), after sham-treatment (n = 5), or after restoration of function of the thyrohyoid muscles with surgical sutures (prosthesis-treatment, n = 6). During trials, the following determinations were made: videoendoscopy of the upper airway, gait frequency and pharyngeal and tracheal static pressures. RESULTS None of the 10 horses developed DDSP during 2 separate treadmill-exercise trials under the control conditions. Seven of the 10 horses developed DDSP after resection of the TH muscles, 4 of 5 of these horses still experienced DDSP after sham-treatment, but 5 of 6 horses no longer experienced DDSP at exercise after the prosthesis-treatment. There were significant anomalies in airway pressures, respiratory frequency, and occurrence of DDSP in both the TH resection and sham-treatment conditions compared to control conditions. In contrast, no statistical differences were noted in any of the parameters measured between the prosthesis-treatment and control conditions. CONCLUSIONS That the function of the TH muscles is important to the stability of the laryngo-palatal relationship and plays a role in the pathophysiology of exercise-induced DDSP. POTENTIAL RELEVANCE Management of horses with DDSP could be enhanced by restoring the function of the TH muscles.

Mechanical nociceptive thresholds in the axial skeleton of horses

REASONS FOR PERFORMING STUDY An objective measure of neck, back and croup pain is needed in horses with musculoskeletal injuries, vague upper limb lameness or poor performance. OBJECTIVES To establish mechanical nociceptive thresholds (MNTs) within the axial skeleton and evaluate the effects of subject status and ridden exercise. METHODS Thirty-six mature horses (10 nonridden; 26 actively ridden) were used to assess MNTs evoked by a pressure algometer (PA) with a 1 cm2 rubber plunger tip at 62 midline and bilaterally symmetrical anatomical landmarks along the axial skeleton. Pressure was applied at a uniform rate of application until a local avoidance reaction was noted. The repeatability of 3 consecutive measurements was evaluated. Left-to-right comparisons and the effects of subject status and ridden exercise on MNTs were assessed. RESULTS MNTs were repeatable and increased in a cranial-to-caudal gradient within the axial skeleton. Typically, there were no significant left-to-right differences. Within-horse variability was less than between-horse variability. Higher MNTs were measured in young, heavy, non-Thoroughbred, castrated males, and in horses that were ridden and actively exercised. CONCLUSIONS AND POTENTIAL RELEVANCE PA provides an objective, noninvasive, and repeatable tool to measure mechanical nociception in horses. MNTs vary in horses with differing subject status and ridden exercise level.