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Decrease in milk yield associated with exposure to bluetongue virus serotype 8 in cattle herds
DOI:10.3168/jds.2012-5800.png)
摘要
En 中文
Decreased milk yield and reduced fertility are the primary consequences of infection by bluetongue virus serotype 8 (BTV-8). These effects must be quantified to fully assess the economic benefit of vaccination. This can be estimated by measuring the effect of BTV-8 exposure on milk yield and fertility for all cows belonging to an infected herd. The objectives of this study were (1) to quantify the mean effect of exposure to BTV-8 on milk yield following natural challenge for cows in herds previously naive, (2) to determine the duration of reduced milk yield before and after the date disease was first detected in the herd to estimate the cumulative loss of milk yield during this period, and (3) to evaluate the influence of the proportion of infected neighboring herds on the reduction in milk yield following exposure to BTV-8. The effects of exposure to BTV-8 during the French outbreak of 2007 were assessed using mixed linear models, which allow adjustment for factors known to influence milk yield. Exposure to BTV-8 was associated with a sharp decrease in milk yield over a period of 6 mo (2 mo before to 4 mo after the reported date of disease detection in the herd). The cumulative loss of milk yield was more than 3% of annual production. The relatively earlier reduction in milk yield in infected herds detected later in the outbreak period suggests that detection of clinical signs was delayed in these herds. Finally, the greatest decrease in milk yield was observed in herds detected early during the outbreak period and located in areas with the highest disease incidence. This may be due to a greater within-herd incidence or to a greater amount of virus injected by midges to individual cows in these herds.
Keyword:
bluetongue
milk yield
cow
epidemiology
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期刊
IF:
4.4
论文数:
2.1W
被引数:
7.2W
机构
引用论文
Reduction in milk yield associated with Mycobacterium avium subspecies paratuberculosis (Map) infection in dairy cows奶牛中与鸟分枝杆菌亚种副结核 (Map) 感染相关的产奶量减少
VETERINARY RESEARCH
IF3.5

