奶牛新孢子虫病血清流行病学调查

本研究用酶联免疫吸附试验（ELISA）对采集自北京地区的94份奶牛血清（随机采集）和河北地区的55份奶牛血清（有流产史奶牛），进行Neospora caninum血清抗体检测。结果发现，北京地区随机采集的奶牛血清N．caninum抗体阳性率为18．1％（17／94），河北地区有流产史的奶牛N．caninum血清抗体阳性率为23．6％（13／55）。采用牛奶记录体系（DHI）对北京地区17头N．caninum血清抗体阳性牛进行了日产奶量、乳中蛋白率和乳脂率的测定，并与同群牛中134头阴性牛比较。结果表明，N．caninum血清抗体阳性牛日产奶量比阴性牛降低9．7％，乳中蛋白率和乳脂率分别降低20％和15．4％。初步证明N．caninum血清抗体阳性奶牛产奶量降低及奶品质的下降。对不同N．caninum抗体滴度阳性牛的泌乳期主要生产性能比较发现，其生产性能的变化与抗体滴度无明显相关性。

Serological epidemiology of Neospora caninum from dairy cattle

Fify five serum samples from aborting dairy cows in Hebei area and 94 random serum samples from dairy cows in Beijing area were tested through Enzyme Linked Immunosorbent assay(ELISA) for antibodies against N.caninum.Antibodies to N.caninum were found in 17 out of 94(18.1%) sera from Beijing,and in 13 out of 55(23.6%) sera from Hebei.Through Dairy Herds Improvement(DHI),94 cows from Beijing were tested for the main production of the milk.It was found that the daily milk yield,the milk protein percentage and butterfat percentage of dairy cows with N.caninum positive serum were 9.7%,20% and 15.4%,respectively lower than that of those with the negative N.caninum serum,Therefore,this pilot study indicated that the decreased milk production may be due to N.caninum infection.However,there was no remarkable relationship between the antibody titers and main quantity and quality of the milk.