奶牛低镁血症的诊治报告

1999年 1 0月上、中旬 ,我场先后有 1 6头奶牛出现以突发性全身肌群痉挛颤抖、后肢僵硬瘫痪为特征的疾病。现就其诊治经过报道如下。1　发病情况在牛群中断断续续零散突发 ,病牛膘情大多良好。在发病的 1 6头牛中 ,1 1头为产前发生 ,5头为产后 1～ 2周内发生。在发病瘫痪后 1 3头侧卧 ,3头趴卧。其中死亡 6头 ,淘汰 7头 ,治愈 3头。2　临床症状大多突然发病 ,不食 ,或突然滑倒瘫痪 ,呈侧卧或趴卧姿式。磨牙吐沫 ,尾肌和后肢僵硬 ,强直性痉挛 ,继而全身肌肉颤抖 ,对外界刺激敏感。严重的角弓反张 ,头弯至身体背侧 ,牙关紧闭。病牛同时还出现…     

Siderocytosis Associated With Hypomagnesaemia in Cattle

Sir:- I wish to report the occurrence of siderocytosis (circulating erythrocytes containing free iron)⁽⁵⁾ in cattle with hypomagnesaemia.     

The effect of induced hypomagnesaemia and hypermagnesaemia on the erythrocyte magnesium concentration in cattle

Hypomagnesaemia was induced in ten yearling Friesian heifers by starving them for forty hours while hypermagnesaemia was induced in seven Friesian calves (about two and half months old) by intramuscular magnesium sulphate (MgSO₄) injection. The plasma magnesium (PMg) concentration decreased (P<0.05) during starvation and increased (P<0.05) following MgSO₄ administration. However the erythrocyte magnesium (EMg) concentration did not show any significant change either with starvation or following the MgSO₄ administration. These results show that sudden and significant changes in PMg concentration do not have any significant effect on EMg concentration. Accordingly EMg concentration may be a better indicator of long-term body Mg status and during hypomagnesaemic tetany could show whether the decrease in PMg concentration was sudden or gradual.     

Suspected botulism in cattle associated with poultry litter

Botulism was diagnosed clinically in grazing cattle on three closely sited dairy farms. The evidence suggests that the source of the toxin was poultry carcases containing types C and D Clostridium botulinum. These organism were also found in the alimentary tract of affected animals. Silage is suspected as having acted as a vehicle for the organisms and, or, toxins in cases which occurred later in housed cattle on one of the farms.     

Enterocolitis in cattle associated with Yersinia pseudotuberculosis infection

A syndrome in cattle of diarrhoea and death associated with enteric Yersinia pseudotuberculosis infection is described. Outbreaks occurred during winter and early spring in adult cattle grazing pastures waterlogged by recent flooding or persistent heavy rain. Antibiotic therapy was effective early in the course of the syndrome. At necropsy there was severe acute enterocolitis, and bacteria consistent with Y. pseudotuberculosis were observed in the lesions. This organism could usually be isolated from the intestines of affected animals but was recovered less often from other organs. Representative isolates were identified as Y. pseudotuberculosis serotype III. The association of this syndrome with waterlogged pastures and low temperatures suggests that these conditions favour transmission of Y. pseudotuberculosis infection in cattle. The role of Y. pseudotuberculosis as primary pathogen requires confirmation.     

Environmental factors associated with lameness in dairy cattle

An epidemiological survey of the incidence of different foot diseases causing lameness was undertaken on 80 French dairy farms between 1979 and 1980. A total of 29.5 cases of lesions per 100 cows was recorded in that period, which represents a higher incidence that of clinical mastitis (20.37).

Data concerning the incidence of foot lesions, farm structures, herd management system, feeding and soil characteristics were analysed using the ξ² test of independence and one-way analysis of variance. Results showed that a high incidence of infectious and metabolic foot disorders was associated with loose housing, feeding based on maize silage, absence of a footbath, foot trimming and mineral supplementation.

A relationship was also observed between articular lesions and grass-silage feeding. Tied-housed cows fed hay were less affected. Regular hoof trimming at pasture and a long time spent checking the animals were found to have a positive effect on foot health. A low incidence of foot disorders was also associated with a larger variety in dietary components. A high incidence of lameness was reported in large herds kept on rough floors.     

Nervous disease associated with coccidiosis in young cattle

Four cases are described of nervous disease associated with coccidiosis in young cattle. Prodromal nystagmus, ventromedial strabismus, sternal or lateral recumbency with contortions of the head and neck, near normal interictal periods and palpable proctitis were common findings. Differentiation from other nervous disorders in young cattle and the pathogenesis of the nervous signs associated with coccidiosis are discussed. It is suggested that the clinical picture is sufficiently distinctive to allow a diagnosis to be made on clinical grounds alone.     

Herd-level factors associated with longevity in Swedish dairy cattle

The aim of this study was to find herd-related factors associated with average longevity in Swedish dairy herds. Herds with short or long (bottom or top quartile) total life (from birth, TL, 841 and 839 herds) or productive life (from first calving, PL, 799 and 821 herds) were chosen. A logistic regression model was used to estimate associations between herd type and herd-related factors. Large herds and herds increasing in size by more than 50% were less likely to have long PL. High average milk yield was not a risk factor for short PL, but herds with the lowest yield were more likely to be long PL herds. These herds had lower estimated breeding values for milk, most likely due to a slower herd turnover rate. A high proportion of cows culled early in first lactation had a large effect on the probability of being a short PL herd.     

Myopathy in young cattle associated with possible myoglobinuria.

Two 10-month-old heifers from a group of 20 young stock showed symptoms closely resembling paralytic myoglobinuria. One animal died five days after the onset of the symptoms and the other recovered slowly with selenium and vitamin E therapy. Histological examination of muscle tissue from the dead animal showed a myopathy resembling that due to vitamin E deficiency.