Subclinical laminitis in dairy heifers

By causing poorer horn quality, subclinical laminitis is considered to be a major predisposing cause of other hoof problems, particularly sole ulcers in newly calved heifers. In this study the hind hooves of 136 female Friesian/Holstein cattle aged between four months and two years were examined to discover at what age the signs of subclinical laminitis appeared. Sole haemorrhages were found in the hoof horn of calves as young as five months. The consistent finding of these lesions in heifers of all ages indicated that subclinical laminitis of varying degree was a common condition during the early growing period of young dairy heifers.     

Subclinical ketosis in lactating dairy cattle.

Subclinical ketosis is an important and common condition of early-lactation dairy cattle. It is associated with losses in milk production and increased risk of periparturient disease. Prevention depends on several factors, including proper transition-cow nutrition, management of body condition, and the use of certain feed additives such as niacin, propylene glycol, and ionophores. All currently available cowside tests for subclinical ketosis have certain limitations in their use. Effective monitoring schemes for subclinical ketosis can be developed, however, and these may be useful in many herd health programs.     

Arteriographical and pathological changes in chronic laminitis in dairy cattle

The arteriographic appearance of 76 bovine hind digits, obtained from a slaughterhouse, was related to the macroscopic signs of chronic laminitis in the digits. There were statistically significant correlations between the macroscopic and the arteriographic appearance of the claws. Subsequent histological examination of the radiographically abnormal arteries revealed features indicative of arteriosclerosis. The results of this study indicate that chronic laminitis develops following a subclinical attack of laminitis due to a continous hypoperfusion of the digit.     

Arteriographical and pathological changes in chronic laminitis in dairy cattle

Summary

The arteriographic appearance of 76 bovine hind digits, obtained from a slaughterhouse, was related to the macroscopic signs of chronic laminitis in the digits. There were statistically significant correlations between the macroscopic and the arteriographic appearance of the claws. Subsequent histological examination of the radiographically abnormal arteries revealed features indicative of arteriosclerosis. The results of this study indicate that chronic laminitis develops following a subclinical attack of laminitis due to a continous hypoperfusion of the digit.     

Subclinical laminitis in dairy cows: use of severity of hoof lesions to rank and evaluate herds

Thirteen high-yielding Holstein herds in Ohio were ranked according to the prevalence and severity of lesions associated with subclinical laminitis (pododermatitis aseptica diffusa). One hundred and seventy-three first lactation cows, most of them in their first 100 days of lactation, and 30 pregnant heifers were assessed. The lesions evaluated were yellow waxy discoloration of the sole, haemorrhage of the sole, separation of the white line, and erosion of the heel. Each herd consisted of more than 100 lactating cows and all the herds were producing over 8500 kg of milk per cow on a rolling herd average basis. The lactating cows were housed in cubicles and maintained in concrete yards. The lesions associated with subclinical laminitis were prevalent among the 13 herds, but when each category of lesion was considered independently, significant differences in prevalence and severity were detected among the herds. These differences suggest that it may be possible to make changes in herd management which may influence the prevalence of lesions.     

Subclinical endometritis in dairy cattle and its effect on fertility--a review of recent publications

Reduced reproductive performance in dairy cattle is often caused by uterine disorders. Beside acute metritis and chronic endometritis recent reports on a negative impact of subclinical endometritis on reproductive performance have been published. Diagnosis of subclinical endometritis can be performed by ultrasonography or cytological examination of the uterus. The cytological examination is based on uterine lavage or the cytobrush-method. Prevalence of subclinical endometritis in different studies ranges from 16 to 90 percent and depends on the diagnostic method and the time postpartum when the examination is performed. Affected cows showed significantly decreased conception rates, prolonged days to first service and days open as well as a reduced number of cows pregnant. Studies on the treatment of subclinical endometritis with prostaglandin F2alpha or analogues, intrauterine antibiotics or proteolytic enzymes showed heterogeneous results and do not allows valid recommendations for veterinary practice.     

奶牛蹄叶炎的研究进展

奶牛蹄叶炎是危害奶牛生产的重要疾病，是牛蹄真皮急性、亚急性和慢性弥散性、无败性炎症，通常可侵害几个指(趾)，呈现局部和全身性症候。由于蹄叶炎可导致蹄变形，蹄底溃疡病及白线病等多种蹄病，给奶牛生产造成的损失十分巨大，是近年来国内外蹄病研究的前沿课题。但到目前为止，在实验研究方面所做的工作较少，奶牛蹄叶炎的病因及发病机理仍不十分清楚。本文从蹄叶炎的病因、症状、治疗、预防等方面做一综述。     

Subclinical ketosis in dairy cows

Subclinical ketosis is defined as a preclinical stage of ketosis. The peak prevalence of subclinical ketosis occurs during the fourth week of lactation. Herd-related factors, breed, parity, and season are other important determinants. Subclinical ketosis can be revealed by determining levels of plasma glucose, plasma NEFA and blood, and milk or urine ketone body concentration. There are theoretical and practical advantages of using milk ketone bodies. Most authors are agreed on approximate lower and upper borderlines for subclinical ketosis. The risk of an outbreak of clinical symptoms has been evaluated by some authors. Most authors have found significant negative relationships between energy balance and ketone body concentration. Some disagreement may be attributable to the fact that the diets used in different experiments can have different glucogenic potential, even if the energy content is the same. This affects the relationship between energy balance and ketone body concentration, as the ketone body level is influenced by both the energy balance and plasma glucose. Feeding silage with high butyric acid content increases the risk of subclinical ketosis. There are indications that cows with the highest milk yield directly after calving are at greatest risk for developing ketosis. Increased ketone body level secondarily reduces milk production, a decrease that has been quantified by some authors. Subclinical ketosis causes delayed reproductive functions return to normal after calving, increased intervals from calving to first and last service, and an increased frequency of ovarian cysts. The routine determination of milk acetone levels in control programs can be used to evaluate the status of individual cows, to indicate the energy feeding in early lactation at a herd level, and to evaluate sires for breeding. The heritability and the tendency toward a positive genetic correlation between milk acetone and milk yield have also been discussed, as have aspects of nutritional prevention. Factors such as energy- and protein-rich roughage, tasty high-energy concentrates, suitable feeding during the dry period, and division of the concentrates into at least four meals are considered to be important.     

奶牛蹄叶炎的诊治

2006年夏季,河北滦县奶牛流行一种牛蹄肿胀的疾病,发病原因尚不明确。本病发病快、恢复慢,用抗风湿类药治疗同时调节酸碱平衡,虽能治愈,但病程较长。由于行动迟缓,有的牛甚     

肥·大·细·胞·与·奶·牛·蹄·叶·炎

奶牛蹄叶炎的确切病因和发病机制没有一致性的结论。陈家璞认为蹄叶炎的主要原因是组胺、毒素和代谢紊乱，而组胺本身就是肥大细胞所释放的生物活性物质之一。关于肥大细胞及其所释放的多种生物活性物质，在生理和病理过程中发挥重要作用已有许多文献报道。尤其是分布于皮肤内的肥大细胞释放组胺、肝素、类胰蛋白酶、类糜蛋白酶、肿瘤坏死因子（TNF—α）、白三烯、前列腺素（PG）、细胞因子等参与Ⅰ型变态反应及许多皮肤性疾病如银屑病、增生性瘢痕、瘢痕性疙瘩、特应性皮炎等疾病的病理过程。但肥大细胞及其所释放的以上生物活性物质在奶牛蹄叶炎发病机制中的作用尚未见报道，故本文应用组织化学方法观察蹄叶炎奶牛蹄部的组织结构、肥大细胞的数量、分布及组化性质，探讨肥大细胞在奶牛蹄叶炎发病过程中的作用，为奶牛蹄叶炎的防治提供新的理论依据。