Electrocardiographic functional diagnosis of the autonomic nervous system in cattle. 1. Electrocardiographic determination of maximum dose for the beta-adrenergic substance isoprenaline

Reference is made to the importance of functional diagnosis of the autonomic nervous system in cattle, and a concept is described by which higher methodological reliability should be obtainable for intra-organic diagnosis of sympathetic nerve activity. What is needed, among others, is to eliminate the autonomous cardiac effect through pharmacological blockade by means of the parasympathetic atropine and the beta-receptor blocker propanolol. The beta-adrenergic substance isoprenaline, required to estimate propranolol blocking action upon the beta-adrenegic receptors, then was injected through indwelling catheters to the external jugular veins of cattle. The doses were between 50 microgram and 560 microgram. Isoprenaline doses between 200 microgram and 250 microgram were established as maximum doses by electrocardiographic examination, determination of heart rate, and clinical observation. Such maximum isoprenaline doses were found to be suitable for checking the extent to which beta-adrenergic blockade of the heart has been caused by beta-receptor blockers. However, sub-maximum isoprenaline doses of something between 100 microgram and 150 microgram should be used to establish the extent to which beta-receptors have caused relaxation of smooth musculature.     

Comparative morphological studies on the vascular systems of testes in cattle, swine, horse and dog under functional conditions]

The metacrylate and latex corrosion techniques were used to establish that the vascular system of testes is based on one coherent principle in common domestic mammals. The cone-shaped Plexus pampiniformis consists of numerous venous rami, between 0.25 mm and 1.0 mm in thickness and forming a dense vascular network, which practically encase the spiral-shaped A. spermatica interna (cooling coil principle). The testicular veins and arteries in the Tunica albuginea constitute a somewhat voluminous layer of vessels for dissipation of heat, with rami branching off radially into the testicular parenchyma. Most of the artieral rami with radial penetration of the testicular parenchyma turn towards the surface in the mediastinum testis for three-shape ramification. The vascular rami are characterised by countless meanders, primarily for temperature control, pulse flattening for more regular and even blood flow, and blood reflex pumping.     

Rapid test for the preclinical postmortem diagnosis of BSE in central nervous system tissue.

The efficacy of a rapid test for detecting PrP(Sc) in central nervous system tissue was evaluated for the postmortem diagnosis of BSE at different times during the course of the disease. One hundred and six samples of brain, at the level of the medulla oblongata, and spinal cord, derived from the experimental study of the pathogenesis of BSE carried out in Great Britain between 1991 and 1995, were examined. PrP(Sc) was detected in the samples from most of the exposed animals killed 32 months or more after they had been exposed to the agent, and before the onset of clinical signs which were first recorded at 35 months. Comparisons with the results of histology, fibril detection, PrP immunohistochemistry and mouse bioassay indicated that the rapid test is at least as sensitive as these conventional confirmatory diagnostic methods and its result can be obtained more quickly.     

Experimental studies on the ketogenic effect of high doses of proteins in dairy cows]

A 14-month feeding experiment was conducted with 16 high-yielding cows, each given a daily supplement of 2 kg soya meal regardless of milk yield or the stage of lactation, in comparison with 8 normally-fed cows. At monthly intervals various parameters of carbohydrate, fat and protein metabolism and of liver function were determined. At the end of the trial, samples of liver were obtained by biopsy for morphological and histochemical examination. Supplementation had a pronounced effect on milk yield and fat content, averaging over 900 kg of milk and 0.2% fat content more than during the preceding year. The parameters of metabolism revealed clear signs of subclinical ketosis, particularly during the first third of the trial period. Changes were greatest during the 3rd and 4th months of the trial, when the protein content of the ration was particularly high (over 3 kg) and when the energy supply ratio was particularly unfavourable (PEQ 300). At the end of the trial some abnormalities were detected in individual animals in the biochemical properties of blood and urine, and the morphological, histochemical and ultrastructural appearance of the liver. These changes included increases in KK, BTS and bilirubin concentrations in the blood; ketonuria, proteinuria; perilobular fat infiltration with glycogen depletion; changes in succinate dehydrogenase and acid phosphatase activities. In most animals the liver seemed to have become adapted to a high protein intake.     

Distribution of bovine virus diarrhoea viral antigens in the central nervous system of cattle with various congenital manifestations.

Distribution of bovine viral diarrhoea virus (BVDV) antigens in the central nervous system (CNS) of 26 cattle persistently BVDV infected, 11 cattle with mucosal disease (MD), and 32 calves with congenital brain malformations was studied using monoclonal antibodies against BVDV epitopes. In persistently infected cattle and in cattle with MD, a widespread infection of neurons was present. Predilection sites for BVDV antigens were the cerebral cortex and the hippocampus. In calves with congenital encephalopathies, viral antigen-containing neurons could only be detected in the CNS of four animals. From the topographical distribution of BVDV antigens in these four postnatal cases with end-stage lesions, no conclusions could be drawn concerning the pathogenesis of BVDV-induced encephalopathies.     

The effect of seasonal undernutrition on the protein fractions in the blood of Moroccan cattle]

In a trial including 84 cattle from three farms near Rabat (Morocco) the influence of undernutrition (dry season September to February) on the concentration of total protein and its fractions in the blood of cattle was investigated. The results out of the field were confirmed by comparing these concentrations during an experimental cycle of sufficient--insufficient--sufficient feed. It was obvious that malnutrition decreases the concentration of total protein and some of its fractions (albumins, gamma-globulins) in the blood by about 10%, while alpha- and beta-globulins remained nearly uneffected.     

Malignant catarrhal fever in Switzerland: 2. Evaluation of the diagnosis]

Malignant catarrhal fever (MCF) is a mostly fatal lymphoproliferative disease of cattle. In 1995 a PCR based method was introduced for the detection of the ovine herpesvirus 2 (OvHV-2), which is regarded as the causative agent of the sheep-associated form of the disease. This PCR can be regarded as a gold standard for the in vivo diagnosis of sheep-associated MCF in cattle (Müller-Doblies et al., 1998). This semi-nested PCR was now used as a reference test for the reassessment of diagnostic criteria in the clinical and post mortem diagnosis that could previously not be quantitated. Based on 83 suspected cases with a complete clinical record the clinical signs were weighted and grouped according to their sensitivity and specificity into lead signs indicative of MCF and frequently accompanying signs supportive for the diagnosis of MCF and general clinical signs that were less reliable for the diagnosis. Differential diagnoses are discussed, which are of particular significance due to their status as OIE list A diseases e.g. foot-and-mouth disease or rinderpest. 38 PCR confirmed cattle with MCF served for the quantitative analysis of organ lesions. For the post mortem diagnosis an essential set of organ samples is defined to permit a reliable histological diagnosis, as the gross pathology often did not give any indication for the diagnosis. These criteria should help to improve the diagnostic efficiency and to select the appropriate laboratory diagnostic procedures for MCF-suspected cattle.     

酒糟培养灵芝提取物对小鼠中枢神经系统的抑制作用观察

为了评价酒糟培养灵芝提取物的药理活性,将小鼠随机分为提取物125 mg/kg体重组、250 mg/kg体重组、500mg/kg体重组,安定组和生理盐水组,观察酒糟培养灵芝的提取物对小鼠自发活动、巴比妥钠阈上剂量致睡眠时间、戊四氮致惊厥的影响。结果显示,提取物的各组、安定组与生理盐水组比较,小鼠的自发活动能极显著减少(P0.01),睡眠时间能显著或极显著延长(P0.05,P0.01),高、中剂量组小鼠的惊厥率显著减少(P0.05)。结果提示,酒糟培养灵芝的提取物对小鼠中枢神经系统具有一定的抑制作用。     

Consequence of dopamine D2 receptor blockade on the hyperphagic effect induced by cannabinoid CB1 and CB2 receptors in layers

1. Endocannabinoids (ECBs) and their receptors play a regulatory function on several physiological processes such as feed-intake behaviour, mainly in the brain. This study was carried out in order to investigate the effects of the dopaminergic D1 and D2 receptors on CB1/CB2 ECB receptor-induced hyperphagia in 3-h feed-deprived neonatal layer chickens.

2. A total of 8 experiments were designed to explore the interplay of these two modulatory systems on feed intake in neonatal chickens. In Experiment 1, chickens were intracerebroventricular (ICV) injected with control solution, l-DOPA (levo-dihydroxyphenylalanine as precursor of dopamine; 125 nmol), 2-AG (2-arachidonoylglycerol as CB₁ receptor agonist; 2 µg) and co-administration of l-DOPA (125 nmol) plus 2-AG (2 µg). Experiments 2–4 were similar to Experiment 1 except birds were injected with either 6-OHDA (6-hydroxydopamine as dopamine synthesis inhibitor; 150 nmol), SCH23390 (D1 receptor antagonist; 5 nmol) and AMI-193 (D2 receptor antagonist; 5 nmol) instead of l-DOPA, respectively. Additionally, Experiments 5–8 followed the previous ones using the same dose of l-DOPA, 6-OHDA and dopamine antagonists except that birds were injected with CB65 (CB2 receptor agonist; 5 µg) instead of 2-AG. Coadministrations were at the same dose for each experiment. Cumulative feed intakes were measured until 120 min after each injection.

3. ICV administration of 6-OHDA and AMI-193 significantly attenuated 2-AG-induced hyperphagia. Interestingly, the hyperphagic effect of CB65 was significantly attenuated by administration of l-DOPA, whereas the administration of 6-OHDA and AMI-193 together amplified the hyperphagic effect of CB65.

4. It was concluded that cannabinoid-induced feeding behaviour is probably modulated by dopamine receptors in neonatal layer-type chickens. It seems that their interaction may be mediated by the D2-dopamine receptor.     

Induction of parturition in cattle: effect of triamcinolone pretreatment on the incidence of retained placenta.

Two experiments were designed to determine whether pretreatment with triamcinolone acetonide (TRI) prior to induction of parturition with dexamethasone (DEX) and cloprostenol (CLO) would reduce the incidence of retained placenta. Experiment 1 was conducted to determine the optimum dosage of TRI and to approximate the optimum interval from TRI to induction with DEX + CLO. All cows received TRI on day 270 of gestation. Cows in group I received 1 mg/30 kg of body weight (BW) of TRI and were induced to calve with DEX + CLO on day 276. Cows in groups II and III received 1 mg/45 kg BW and were induced on days 276 or 277, respectively. Cows in groups IV and V received 1 mg/60 kg BW and were induced on days 277 or 278, respectively. Group VI cows served as untreated controls. There was no difference in the incidence of retained placenta among the treated and control groups. Experiment 2 was conducted to more precisely determine the optimum interval from pretreatment to induction treatment with the chosen dose of TRI. All cows in groups I, II, and III were pretreated with 1 mg/60 kg BW of TRI on day 270 of gestation and received DEX + CLO on days 275, 276 or 277, respectively. Group IV cows served as untreated controls. The incidence of retained placenta was higher (p < 0.05) in groups I and II than in the control group, with group III intermediate and not different from the others.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of steroid hormone doses after ovariectomy on the peripheral hormone processes and uterine development in gilts. 2. Effects on gilts during early pregnancy

Experimental studies were conducted into ovariectomized pregnant gilts to establish effects of exogenic hormone administration, with endogenic ovarian steroids excluded, upon uterus and fetus development as well as on hormone levels in blood plasma, endometrium, and allantoic fluid. Hormone concentrations in blood plasma were found to depend clearly on hormone doses applied after ovariectomy to preserve pregnancy. 2 to 3 weeks of smooth gravidity, following ovariectomy, were ensured on the 6th or 14th day after KB1 by daily application of very low doses of progesterone only (80 mg) or in combination with estrogens, the ratio being 480:1.     

Comparison of purified protein derivatives and effect of skin testing on results of a commercial gamma interferon assay for diagnosis of tuberculosis in cattle.

Purified protein derivatives (PPD) prepared in the USA were compared with those prepared in Australia by a private company (CSL Veterinary) for use with a commercial gamma interferon (gamma-IFN) assay for diagnosis of bovine tuberculosis. The effect of skin testing on results of the gamma-IFN assay was determined, and results were compared when blood samples were stimulated with PPD within 2 hours and after 24 hours of sample collection. Twenty cattle that were sensitized by subcutaneous injection of heat-killed Mycobacterium bovis were randomly divided into 3 groups. Cattle in group A were tested with the caudal fold skin test (CFT) on day 0 and the comparative cervical skin test (CCT) on day 7. Cattle in group B were tested with the CFT on day 0 and the CCT on day 63, and group C cattle were not skin tested. Blood samples for the gamma-IFN assay were collected at various times throughout the study period. Optical density (OD) values for the gamma-IFN assay were not significantly different when blood samples were stimulated with US avian PPD and CSL avian PPD. However, OD values were significantly higher for US bovine PPD than for CSL bovine PPD. However, the final interpretation of the gamma-IFN assay was usually the same when using either US or CSL PPD. In addition, OD values for the gamma-IFN assay were significantly higher for blood samples collected after sensitized cattle were skin tested than for samples collected from the same cattle before skin testing or from cattle not skin tested. The OD values for blood samples stimulated within 2 hours of sample collection were significantly higher than for samples stimulated 24 hours after sample collection. However, OD values for all PPD-stimulated samples from sensitized cattle were significantly higher in samples collected 3 days after skin testing and stimulated 24 hours after collection than for samples from the same animals collected before skin testing and stimulated within 2 hours of sample collection. Results of this study indicate that PPD prepared in the USA or Australia can be used to stimulate blood samples for the gamma-IFN assay. Skin testing cattle prior to collection of blood for the gamma-IFN assay boosts production of gamma-IFN by lymphocytes from cattle that have had prior exposure to M. bovis antigens. Use of the gamma-IFN assay in conjunction with skin testing may improve detection of cattle infected with M. bovis. In addition, the increase in production of gamma-IFN after skin testing will permit greater flexibility in conducting the assay because samples can be stimulated after they have been shipped overnight rather than only on the day of sample collection.     

An immunohistochemical and ultrastructural study on age-related astrocytic gliosis in the central nervous system of dogs.

The pattern of astrocytic gliosis (AG) was examined in 2-month-old to 18-year-old dogs using glial fibrillary acidic protein (GFAP) immunohistochemistry and electron microscopy. Coronal sections from various levels of the central nervous system (CNS) were stained with hematoxylin & eosin, Luxol Fast Blue, Nissl, and Bodian in addition to GFAP. A consistent pattern of age-related AG was observed in the dogs. The white matter, cortico-medullary junction, and subcortical nuclei in the cerebrum, central nuclei in the cerebellum, various nuclei in the brain stem, and grey matter of the spinal cord showed even and intense GFAP staining. AG was also prominent in the cerebral and cerebellar cortices and thalamus. Moderate AG was observed in the hippocampus and white matter of the cerebellum and spinal cord. Electron microscopy demonstrated increased number of profiles of degenerative neural components in the vicinity of hypertrophic astrocytes in the cerebral cortex of the aged dogs. Moderate to severe AG was consistently shown in the CNS of the aged dogs. In contrast, young normal dogs showed minimum amounts of GFAP-positive astrocytes in the CNS. These findings suggest that the observed AG in the CNS of the dogs is a morphological expression of aging.     

Subacute butyric acid exposure in cattle. 4. Clinical influence and effect on the carbohydrate-fat metabolism and liver function of cows

Eleven cows in late lactation were exposed to butyric acid for three weeks and were compared to five controls. Two intraruminal doses were daily applied, that is 1.0 g/kg B.W. of butyric acid to six animals and 1.0 g/kg B.W. of sodium butyrate to another five. Decline in milk yield was clinically recorded in response to butyric acid, while muscle tremor and diarrhoea resulted additionally from sodium butyrate. Behaviours of the clinico-chemical parameters of beta-OH-butyrate, glucose, free fatty acids, bilirubin, ASAT, gamma-GT, AP, and cholesterol were comparable to those in fattening bulls. Liver damage was not safely established. Some of the clinico-chemical alterations were more strongly pronounced after administration of sodium butyrate. One cow fell ill with ketosis under butyric acid load.     

Variability of serum bile acid concentrations over time in dairy cattle, and effect of feed deprivation on the variability.

Twelve nonlactating dairy cows, free of signs of liver disease and with normal serum activities of liver-derived enzymes and normal liver biopsy tissue, were examined over a 72-hour period for serum total bile acid concentrations. The cattle were fed hay twice daily, and blood samples were obtained every hour for 24 hours, every other hour for 24 hours, then every hour for 24 hours. After 3 weeks, the study was repeated on 6 of the cattle, thus providing data for eighteen 72-hour periods. Serum bile acid concentration varied greatly over the 72 hours, with the range being from one third to 3 times the median. There were variations by as much as 60 mumol/L from 1 hour to the next. After another 3 weeks, 8 of the cattle were deprived of hay for 48 hours and then fed hay morning and afternoon of the third (last) day of the study. There was no significant reduction in bile acid concentration after withholding the hay, but the variability was reduced (P = 0.02) during the last 20 hours of the hay-deprivation period. In 3 ancillary studies, serum bile acid concentrations were examined over a 48-hour period in 2 cows in early lactation, 3 cows in midlactation, and two 6-month-old heifers. The cows were fed hay and grain twice daily, and the heifers were fed only hay twice daily. In comparison with values for the 12 nonlactating cows fed hay twice daily, mean serum bile acid concentration in the recently freshened cows was significantly (P < 0.002) higher (62.9 vs 22.0 mumol/L).(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of gonadotropin releasing hormone (GnRH) and analogs on the conception rate in cattle. A critical literature review

The objective of this article was to review the current literature of the influence of gonadotropin releasing hormone (GnRH) and GnRH agonists on conception rate in dairy cattle. The application of GnRH or agonists at artificial insemination (first and subsequent) and between days 7 and 34 after parturition were considered. The variations between studies were discussed as well as different mechanisms concerning the influence of GnRH for establishing pregnancy. From a critical point of view the routine use of GnRH or agonists at the time of first or subsequent breeding or during the postpartum period cannot be supported.