Rhinopneumonia or mycotoxin intoxication? Neurologic phenomena in horses from a riding school

In the course of several days most of the 40 riding-school horses turned out in paddocks developed ataxia of variable severity. Five of these horses showed severe ataxia and tremors, became paralyzed and were euthanized. Eleven privately-owned horses which were stabled on the same premises showed no clinical signs. The most likely diagnosis seemed to be the 'neurological form of EHV1', although the signs were not entirely typical. A few weeks later a second outbreak occurred among the riding-school horses and one of the privately-owned horses also showed signs of ataxia. In the meantime it had been shown that EHV1 titers in paired serum samples had not increased and that the cerebrospinal fluid of one of the severely affected horses was normal. Toxicological examination of hay, delivered just before the first outbreak and stored for the winter, showed a significantly increased concentration of lolitrem B mycotoxin (5-6 mg/kg). The hay appeared to have been made of ryegrass used for lawns and playing fields. Retrospectively it became probable that this hay occasionally been fed to the horses just before the onset of clinical problems. It is concluded that the horses showed the 'ryegrass-stagger syndrome'.     

Efficacy of toltrazuril in broilers and development of a laboratory model for sensitivity testing of Eimeria field isolates

(1) The efficacy of toltrazuril (Baycox) against coccidiosis was established on a broiler farm in an intermittent application during five consecutive growing periods. Treated birds were fed a broiler ration without anticoccidials. The efficacy of Baycox was compared with the nicarbazin-salinomycin shuttle. It was concluded that Baycox retarded the onset of Eimeria infection for several weeks. During the fifth rearing period coccidiosis problems emerged on the farm in all birds during medication, suggesting development of resistance. (2) During a laboratory experiment the efficacy of Baycox was studied in birds after inoculation with different numbers of oocysts at 7, 10 or 15 days of age. Baycox was applied at 10 and 11 days of age. In all cases medication with Baycox protected birds from coccidiosis during a period of at least 7 days. This effect of Baycox could be due to the long-existing tissue levels of the product and its metabolites as well as its specific effect on the second generation of schizonts. (3) In another laboratory experiment coccidia obtained from field trials were tested for sensitivity to Baycox in conjunction with two strains obtained from farms were coccidiosis emerged during application. The inoculation model developed in this study was used for sensitivity testing. One of the Eimeria strains tested was resistant to the product, one strain was tolerant and the remaining two strains, including the control strain, were fully sensitive to Baycox.     

Variation of fiber types in the triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris of horses

The distribution of type-I and type-II fibers in 9 different parts of the musculi triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris was studied to determine whether biopsies from these muscles give reliable information. All 4 investigated muscles were not homogeneous in their fiber-type distribution. Large differences existed among different muscle parts. The percentage of type-I fibers increased toward the deeper and cranial parts of the muscles. In the same zone of the gluteus muscle, differences of 30% were found for type-I fibers. Therefore, results obtained by biopsies of muscles must be interpreted with caution.     

Lactic acid as a decontaminant in slaughter and processing procedures

An attempt was made to interrelate the data obtained in experiments conducted by our Department along beef, veal and pig slaughter lines, using lactic acid (LA) for the decontamination of carcasses, cold and hot boned primal cuts, slaughter byproducts, and butcher's knives. First and foremost it was observed, that provided Good Manufacturing Practices are strictly followed, the microbial load of carcass surfaces will be substantially reduced. LA-decontamination may result in an additional reduction. Since in the early post-mortem period bacteria are not yet attached to the meat surface, LA-decontamination should preferably be applied to the hot carcass. It was demonstrated that, dependent on mode and duration of application, LA sprays not exceeding 1% v/v (beef), 1.25% v/v (veal) and 1.5% v/v (pork) resulted in acceptable carcass colour scores. Blood spots, which are particularly prone to discolouration by lactic acid application, should be removed at an early post-mortem stage e.g. by strong showering. The difference in surface pH between LA-treated and control carcasses disappeared within 72 hours post-mortem. Veal longissimus chops treated with LA solutions up to 2% v/v were not identified by a consumer taste panel as significantly different from controls. The 'immediate' bactericidal effect of LA-decontamination for beef, veal and pig carcasses, as well as for pig liver and veal brain, amounted to approximately 1.5 log cycles for the aerobic colony counts, strongly dependent on substrate and conditions of decontamination. In addition, a 'delayed' bacteriostatic effect was observed during storage, which is probably the result of a prolonged lag phase of acid-injured micro-organisms surviving lactic acid decontamination.(ABSTRACT TRUNCATED AT 250 WORDS)     

Induction of diplodiosis, a neuromycotoxicosis, in domestic ruminants with cultures of indigenous and exotic isolates of Diplodia maydis

Diplodiosis, a neuromycotoxicosis, principally of cattle, which is characterized by ataxia, paresis and paralysis, was induced in 13 cattle, 16 sheep and 3 goats, by dosing them with Diplodia maydis [= D. zeae (Schw.) Lév.] cultured on sterilized maize seeds. The results of these experiments confirmed the findings of earlier workers that diplodiosis is a mycotoxicosis caused by D. maydis. The intoxication was induced with cultures of South African isolates of D. maydis obtained from local maize, one of which was associated with a suspected field outbreak, and with cultures of isolates from maize imported from the United States of America and Argentina. Other findings emerging from the experiments were, inter alia, that cultures incubated for less than 8 weeks were seemingly non-toxic, that there was little individual variation in response of cattle to cultures of the different toxic isolates or batches of the isolates, that apparent relapses of clinical signs can occur several weeks after dosing had ceased and that a small percentage of animals can show permanent locomotory disturbance. Light microscopical examination revealed no lesions in acutely affected animals, but an extensive laminar subcortical status spongiosis was evident in the cerebrum and cerebellum of a sheep that had been long paralysed and a steer that had permanent locomotory disturbance.     

Ocular changes in a cat with disseminated blastomycosis

A domestic shorthair cat examined because of dyspnea was found to have ophthalmoscopic and radiographic changes suggestive of systemic mycosis. The cat died despite antifungal therapy. Histologic examination revealed Blastomyces dermatitidis in the eyes, brain, lungs, stomach, liver, kidneys, spleen, pancreas, and adrenal glands. The pathologic changes were similar, but more widespread than those typically seen with canine blastomycosis.     

Describing the growth and molt of modern domestic turkey (Meleagris gallopavo) primary wing feathers

The use of feathers as noninvasive physiological measurements of biomarkers in poultry research is expanding. Feather molting patterns and growth rates, however, are not well described in domestic poultry. These parameters could influence the measurement of these biomarkers. Therefore, the objective of this study was to describe the juvenile primary feather molting patterns and feather growth rates for domestic turkeys. The 10 primary wing feathers of 48 female turkeys were measured weekly from week 1 (0 d of age) to week 20. Feathers were manually measured, and the presence or absence of each primary feather was recorded weekly. Generalized linear mixed models were used to investigate if feather growth differed between the primary feathers. The molting of the juvenile primary feathers followed a typical descending pattern starting with P1 (5 wk of age), while P9 and P10 had not molted by the end of the study (20 wk of age). The average feather growth rate was 2.4 cm/wk, although there was a significant difference between the 10 primary feathers (P < 0.0001, 2.1 to 2.8 cm/wk). Over time, feather growth followed a pattern where the growth rate reaches a peak and then declines until the feather is molted. The results of this study provide a critical update of patterns of molting and feather growth in primary wing feathers of modern turkeys. This can have implications for the interpretation of physiological biomarkers, such as the longitudinal deposition of corticosterone, in the feathers of domestic turkeys.     

Vitamin and trace mineral content in feed of breeders and their progeny: effects of growth, feed conversion and severity of malabsorption syndrome of broilers

1. A study was conducted to investigate the effects of several vitamins and trace elements chickens and in chickens experimentally infected with malabsorption syndrome (MAS). 2. Vitamins and trace minerals in feed were varied. Breeders received either a basal amount of vitamins and trace minerals (low mix) or an increased amount (high mix). Their progeny also received either a low mix or a high mix. Effects of different breeder and broiler mix combinations on broiler performance, heamatology, spleen weight and humoral response were examined in control chickens. The effects of the different feeds and breeder, broiler combinations at the severity and recovery of MAS infection were also studied. 3. In general, the immune system can be stimulated by addition of vitamins and trace minerals, without affecting the growth potential of the controls. The number of leukocytes increased on d 1 in the broilers descended from breeders receiving high mix. The response to Newcastle disease virus boost was affected by the different amount of vitamins. 4. When breeders received a high mix the number of infiltrating polymorphonuclear leukocytes in the intestine was higher compared with breeders receiving basal amounts of minerals and vitamins. Also the recovery rate of intestinal lesions, cystic crypts of Lieberkühn and villus atrophy, as observed by histopathology, was faster in the groups where the breeders received high mix.