Nardone A
Department of Animal Production, Faculty of Agriculture, University of Tuscia, Via S. Camillo de Lellis, 01100 Viterbo, Italy.
Vet Res Commun. 2003 Sep;27 Suppl 1:39-52. doi: 10.1023/b:verc.0000014116.19632.8a.
The small number of BSE cases diagnosed in Italy from January 2001 to 12 September 2001 (a total of 28, one every 9000 head) does not allow for a statistical analysis of the relationship between this disease and the livestock systems. However, some indications can be noted: (a) only dairy cattle, which represent three-quarters of the cattle raised in Italy, are involved; (b) 58% of the cases belong to medium-large farms that breed 27% of all head; (c) 13 out of 28 cases are 5-year-old animals and 26 out of 28 are between 5 and 7 years of age; (d) 15 of 28 cases come from Lombardia, where 27% of Italian dairy cattle are raised. The following factors may have affected the livestock system: (1) trends of beef meat consumption; (2) changes in livestock management; (3) changes in animal feeding; (4) possible effects on selection. A strong decline in beef meat consumption (4 kg/year) has been observed in the UK and other European countries since 1996 (the year of the discovery of the relationship between BSE and nvCJD). In Italy, from January 2001 the consumption of beef meat has declined as well as slaughter: a drop of 31% in the total slaughtered head in the period January-February, a drop of 14% in January-May. A fall in the price of calves has promoted, in some dairy farms, the start of the production of light beef less than one year old (advantages in the marketing of meat favour this initiative), a phenomenon which is not yet well established. Traceability and certification of meat have improved, thanks to breeders' associations and interprofessional agreements. The breeders associations have also started insurance initiatives against BSE risks. In Italy the employment of plant protein meals would increase the total feedstuff consumption by about 7%. Direct effects of BSE could slow down the genetic progress (GP) of cattle populations within breed and country. Indirect effects on GP may also happen as a consequence of an increase in the replacement rate (rr). This increase in rr reduced the generation interval and will therefore proportionally increase GP. Some important questions for the livestock production system are: Does the vertical transmission of BSE exist? Is there a genetic basis favouring the disease and is it inheritable? Are in vivo diagnostic tests possible? Are vaccination schemes against BSE possible and useful or is it better to pursue eradication?
2001年1月至2001年9月12日期间，意大利确诊的疯牛病病例数量较少（共计28例，每9000头牛中有1例），因此无法对这种疾病与畜牧系统之间的关系进行统计分析。然而，可以注意到一些迹象：(a) 仅涉及占意大利饲养牛四分之三的奶牛；(b) 58%的病例属于饲养所有牛数量27%的中型至大型农场；(c) 28例病例中有13例是5岁的动物，28例中有26例年龄在5至7岁之间；(d) 28例病例中有15例来自伦巴第大区，该地区饲养了27%的意大利奶牛。以下因素可能影响了畜牧系统：(1) 牛肉消费趋势；(2) 畜牧管理的变化；(3) 动物饲料的变化；(4) 对选种的可能影响。自1996年（发现疯牛病与新型克雅氏病之间关系的年份）以来，英国和其他欧洲国家观察到牛肉消费量大幅下降（每年4千克）。在意大利，自2001年1月以来，牛肉消费和屠宰量也有所下降：1月至2月期间屠宰总量下降了31%，1月至5月下降了14%。犊牛价格下跌促使一些奶牛场开始生产不到一岁的嫩牛肉（肉类销售优势有利于这一举措），这一现象尚未完全确立。由于养殖者协会和行业间协议，肉类的可追溯性和认证得到了改善。养殖者协会还启动了针对疯牛病风险的保险举措。在意大利，使用植物蛋白饲料将使总饲料消费量增加约7%。疯牛病的直接影响可能会减缓品种和国家内牛群的遗传进展（GP）。由于替代率（rr）的增加，也可能对GP产生间接影响。rr的这种增加缩短了世代间隔，因此将按比例增加GP。畜牧生产系统面临的一些重要问题是：疯牛病是否存在垂直传播？是否存在有利于该疾病的遗传基础且是否可遗传？是否可以进行体内诊断测试？是否可以制定针对疯牛病的疫苗接种计划且是否有用，还是根除更好？
