Results of adrenalectomy in 36 dogs with hyperadrenocorticism caused by adrenocortical tumour

Summary

A total of 38 adrenocortical tumours were removed from 36 dogs with hyperadrenocorticism. The surgical approach was by way of a unilateral flank laparotomy (32 dogs; 14 left and 18 right), a bilateral flank laparotomy (3 dogs) or a midline celiotomy (1 dog).

Two dogs were euthanized during surgery because their tumours could not be resected. Eight dogs died from post‐operative complications. Pancreatic necrosis with peritonitis was the most common cause of death. Eight of the 26 dogs that survived had signs of recurrence of hyperadrenocorticism. Unsuppressible hyperadrenocorticism was found in four dogs; one dog had probably pre‐existent pituitary‐dependent hyperadrenocorticism, and adrenocortical function could not be re‐examined in the remaining three dogs.

Among the 37 tumours examined microscopically expansion of neoplastic tissue into blood vessels was found in 22 of them. Four adrenal glands with adrenocortical tumours also contained phaeochromocytomas. Necropsy was performed in eight dogs. Metastases were found in the lungs of two dogs and in the lungs and liver in one dog.

In combination with the data of previous reports, it is suggested that histological findings in surgery specimens are not good predictors for the clinical outcome.     

Monitoring and identification of residues of anabolic preparations in slaughtered cattle by HPLC with diode array detection

Summary

The new combination of isocratic high performance liquid chromatography (HPLC) with on line UV spectrum detection via a diode array configuration has been applied to the detection and identification of anabolics present in application sites of cattle.

Combination of the characteristic retention time in the HPLC chromatogram and a comparison of the full spectrum between 190–400 nm of the anabolic components with that of a standard resulted in a very reliable identification. By means of this method 117 samples of application sites were investigated for the presence of anabolic residues. Of the xenobiotic anabolics, 19‐nortestosterone (NT) was found most frequently (in 96 cases), whereas diethylstilbestrol (DES) was found in only 11 cases.

In all samples the identification of NT and DES was confirmed by high resolution gas chromatography‐mass spectrometry (GCMS).     

Hepatic lipidosis in pregnant cows on a dairy farm

Summary

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period.

After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.     

Polyglandular deficiency syndrome in a boxer dog: Thyroid hormone and glucocorticoid deficiency

Summary

Primary hypothyroidism and partial primary adrenocortical deficiency (isolated glucocorticoid deficiency) were diagnosed in an 8‐year‐old spayed female boxer dog, presented because of progressive symmetrical truncal alopecia, lethargy, and intolerance to cold. The diagnosis was based upon the combination of low, non‐TSH‐responsive concentrations of plasma thyroxine and low urinary excretion of corticoids together with high plasma concentrations of ACTH. Normal suppressibility of ACTH concentrations by a low dose of dexamethasone indicated an intact feedback system. Plasma growth hormone levels were elevated, most probably because somatostatin release was depressed by the glucocorticoid deficiency.

The dog improved during oral replacement therapy with thyroxine until death ensued after 9 months as a result of intercurrent disease. Autopsy revealed thyroid atrophy and lymphocytic adrenalitis with complete destruction of the zona fasciculata and zona reticularis of the adrenal cortex.

The combination of primary hypothyroidism and primary adrenocortical deficiency in this dog is identical to the entity known as type II polyglandular autoimmunity or Schmidt's syndrome in humans. The adrenocortical insufficiency remained confined to glucocorticoid deficiency during the observation period; on no occasion did electrolyte concentrations in the plasma reach values suggestive of mineralocorticoid deficiency.     

Relationship between latency of brainstem auditory‐evoked potentials and head size in dogs

Summary

Cranium and brainstem dimensions were measured in 32 postmortem dog heads. Positive correlations were found between cranium length (CL) and brainstem length (BL) (r=0.87), between cranium width (CW) and brainstem width (BW) (r=0.83), and between cranium distance (CD = CL CW/2) and brainstem distance (BD = BL+BW/2) (r=0.91). Positive correlation coefficients were also found between CL and CW (r=0.90), and between BL and BW (r=0.85). It was concluded that head size accurately reflected brainstem size. A least squares estimation of the brainstem distance (BD) from CL and CW values was BD = 10.9 + 0.16 (CL CW/2) (BD, CL and CW in mm).

Brainstem auditory evoked potentials (BAEPs) and cranium dimensions were measured in 43 dogs (86 ears) with different head size, body size, sex and age. Wave form, absolute and interpeak latencies and correlation coefficients, relating latencies to cranium dimensions and body weight, were analysed CL, CW, and CD were positively correlated with body weight (r=0.93, 0.70 and 0.93, respectively), and CL, CW, and CD were correlated with age (r=0.33, 0.52 and 0.40, respectively). BAEPs consisted of five distinct positive peaks (I to V). Secondary positive peaks following peaks I and II were seen in 60% (I') and 90% (II') of the recordings. Late waves were recorded in 90% (VI), 50% (VII), and 25% (VIII) of the recordings. Latencies increased with decreasing stimulus intensity level (from 90 dB to 10 dB hearing level, HL),especially for peaks I, II, V, and the I‐V interpeak interval Absolute and interpeak latencies were positively correlated with cranium distance and body weight. Correlation coefficients increased as wave latencies increased At 90 dB HL, the highest correlation coefficients, relating cranium distance to peak V and the I‐V interpeak latency, were 0.55 and 0.53 (P < 0.00001), respectively. Regression analysis showed that each 1 cm increase in cranium distance was accompanied by an increase of 0.006 ms in the latency of wave I, 0.03 ms for wave III, 0.05 ms for wave V, and 0.05 ms for the I‐V interpeak interval Regression analysis showed that an increase of 1 kg in body weight was accompanied by an increase of 0.001 ms in the latency of wave I, 0.005 ms for wave III, 0.011 ms for wave V, and 0.01 ms for the I‐V interpeak interval. It is concluded that head size, which accurately reflects brain size, is a relevant source (25%) of intersubject variance of BAEP latencies in the dog.     

Genuine concurrent muscular subvalvular subaortic stenosis and muscular infundibular stenosis of the right ventricle in the heart of the pig

Summary

Two cases of genuine concurrent muscular subvalvular aortic and muscular infundibular pulmonary stenosis in pigs are reported. The character of this morphophy‐siological syndrome is discussed.

The morphology of the heart of the pig predisposes this animal to the syndrome.     

Involvement of spleen components of mature fowl in the primary and secondary humoral antibody response following experimental EDS'76 virus infection

Summary

Cellular changes in spleens of mature fowl in relation to both the primary and secondary humoral antibody response following experimentalEDS'76 virus infection were studied. The influence of splenectomy on humoral antibody response was also examined.

Experimental fowl had been naturally infected with fowl adenovirus (FAV) but did not possess precipitins to these viruses at the time of EDS’ 76 virus infection. Since EDS'76 infection provokes a recall of the group antibody to FAV, this infection simultaneously induces a primary response against EDS’ 76 virus and a secondary response due to the recall of the group antibody to FAV.

HI and precipitating antibodies toEDS'76 virus (primary response) werefirst detected at 6 and 8 days p.i. respectively. Curves of HI, precipating and neutralising antibody titres were biphasic; the first peak (IgM peak) occurred at 10–11 days p.i., the second (IgG peak) at 16–28 days p.i.

Precipitating antibodies to FAV (secondary response) were demonstrated from 4 days p.i. The curve of these antibody titres was also biphasic, with peaks at the same times as in the primary response.

Based on HI and AGP testing of primary and secondary immune response in both splenectomised and non‐splenectomised fowl it is concluded that in the primary response the spleen of the adult fowl is involved significantly in only IgM secretion, while in the secondary response it is likely that bothIgM and IgG are secreted in considerable amounts.

Clusters of lymphoblasts and plasmablasts were observed at 3 days p.i. in the red pulp. It is very likely that antigen‐antibody complexes are formed from that time and circulate bound to the surface of lymphocytes. These antigen‐loaded lymphocytes are ‘picked up’ from the blood stream by

– red pulp macrophages, leading to enhanced formation of lymphoblasts in the red pulp. Great numbers of these cells (which are very probably IgM secreting cells) were present on days 6 and 7 p.i., but were no longer detectable after day 10 p.i.

– macrophages of the macrophagalellipsoidal corona (MEC), leading to significant enlargement of the periellipsoidal lymphoid tissue(PELT) by an increase of the number of lymphocytes observedfrom days 4–12 p.i. The MEC was significantly enlarged from 7–12 days p.i., very likely due to an increased number of macrophages.

Following deposition of antigen in the white pulp, formation of follicles begins. The number of small, intact follicles includingfollicle precursors increasedfrom 6 days p.i. From 15 days p.i. to the end of the experiment both the number and size of follicles increased significantly.

Uptake and processing of antigen by macrophages is probably accompanied by death of some of these cells. This might explain the degenerative changes observed in large mesenchymal cells, probably macrophages, at 3 and 5 days p.i. in the red pulp and at 5 and 6 days especially in the MEC. Splenitis which was present at 3 and 5 days p.i. and oedema observed in and around ellipsoidal cells at 5 days p.i. may be due to mediators released from these degenerative macrophages.

A significantly increased number of follicles with lymphoblasts was seen from 2–15 days p.i. while lymphoblasts and plasmablasts were present in the PELT from 5–15 days p.i., but predominantly at 6 and 7 days p.i. It is likely that disruption of follicles and blast transformation of white pulp lymphoid cells are secondary response events. White pulp lymphoblastsand plasmablastsare probably IgG secreting cells.

Splenomegaly was observed at 3, 5 and 6 days after infection and was mainly due to swelling of red pulp macrophages and infiltration of granulocytes in the red pulp. Ellipsoidal and periellipsoidal changes could contribute to the splenomegaly at 5 and 6 days p.i.     

Extrahepatic cholestasis in the dog and the differentiation of extrahepatic and intrahepatic cholestasis

Summary

The clinical and pathological features of extrahepatic cholestasis in 19 dogs are presented. The condition was most often caused by partial or complete occlusion of the choledochal duct due to neoplastic diseases (12 cases), inflammatory processes (3 cases), or eventration and incarceration of the liver (I case). In only three cases was the condition due to intraluminal obstruction of the choledochal duct.

The anamnestic, laboratory and pathological parameters of these 19 dogs were compared with the findings in 21 dogs with intrahepatic cholestasis. Statistical analysis of these parameters indicated that the presence of acholic faeces, the degree of icterus and the level of plasma γGT where the only parameters of value in the clinical differentation of extrahepatic from intrahepatic cholestasis.

Histological examination of liver biopsies is a simple aid to a confident in vivo diagnosis of extrahepatic cholestasis.     

Swine dysentery in a sow herd

Summary

An acute outbreak of swine dysentery (Doyle) on a farrowing farm is described. Besides clinical signs of enteritis a general loss of condition was seen throughout the herd. This resulted in a decreased fertility and breeding performance among sows and an increase in piglet mortality. Several dehydrated sows aborted.

The outbreak was stopped by oral treatment with lincomycin/spectinomycin 1:1. In the course of the treatment all animals and buildings were washed and disinfected. The use of pharmacotherapeutics in treating swine dysentery is discussed with emphasis on the involuntary induction of carriers.     

Vaccines against Aujeszky's disease: Evaluation of their efficacy under standardized laboratory conditions

Summary

A standardized test was developed to compare the efficacy of Aujeszky's disease virus (ADV) vaccines under laboratory conditions. Per test 3 groups of 6 to 8 sero‐negative pigs were used. The first vaccination was done at 10 weeks of age. One group was vaccinated once, another was vaccinated twice and the 3rd served as control. Pigs were challenge exposed to the virulent NIA‐3 strain of ADV 12 weeks after the first vaccination. Apart from mortality, average periods of growth arrest, fever and virus shedding after challenge were used as parameters to evaluate vaccine efficacy.

Two inactivated and 4 attenuated vaccines were tested. Two attenuated vaccine viruses were excreted after vaccination. Despite maximal standardization, a considerable variation still existed between the experiments in mortality and growth arrest periods of control pigs after challenge. However, the controls were always more severely affected than the vaccinated pigs. All vaccines except one were effective in preventing death after challenge, but none conferred complete protection. Most vaccinated pigs still lost weight, developed fever and shed virus after challenge. Revaccination after 3 or 4 weeks had little effect, particularly with the attenuated vaccines. The results of the present study indicate that 2 of the attenuated vaccines conferred the best protection, I attenuated vaccine appeared to be as effective as the 2 inactivated ones, and the 4th attenuated vaccine was least effective.