Waldner C L, Henderson J, Wu J T, Breker K, Chow E Y
Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, 52 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W0.
Can Vet J. 2001 May;42(5):355-60.
This study examines the long-term impact of a Neospora caninum-associated abortion outbreak in a large cow-calf herd in northern Alberta. Blood samples were collected 4 times from all bred females and heifer calves born during the spring before the outbreak: (1) at the time of the outbreak, (2) the following spring, (3) the subsequent fall, and, finally, (4) the second spring after the outbreak. The samples were analyzed using a commercially available enzyme-linked immunosorbent assay for N. caninum. Calves born immediately following the outbreak were also monitored. Individual calving or abortion records were available from all cows for 2 calving seasons. All cows and heifers were pregnancy tested after the 2 subsequent breeding seasons. At the time of the abortion outbreak in 1997, 81% of all bred females and 87% of the heifer calves were serologically positive. In spring 1998, 49% of the cows and 47% of the heifer calves remained positive. In fall 1998, 48% of the remaining cows and heifers were serologically positive. After the first breeding season following the outbreak (1998), 13.5% of the heifers and 22.2% of the cows were open (not pregnant). Animals that were serologically positive in the spring were more likely to be open in the fall (odds ratio, 2.0; 95% confidence interval, 1.1 to 3.7). No subsequent associations with increased risk of abortion, stillbirth, or nonpregnancy were identified.
本研究调查了阿尔伯塔省北部一个大型母牛-犊牛群中新孢子虫相关流产疫情的长期影响。在疫情爆发前的春季，对所有怀孕母牛和出生的小母牛犊采集了4次血样：（1）在疫情爆发时，（2）次年春季，（3）随后的秋季，最后（4）疫情爆发后的第二个春季。使用市售的新孢子虫酶联免疫吸附试验对样本进行分析。对疫情爆发后立即出生的犊牛也进行了监测。所有母牛有两个产犊季节的个体产犊或流产记录。在随后的两个繁殖季节后，对所有母牛和小母牛进行了妊娠检测。1997年流产疫情爆发时，所有怀孕母牛中有81%、小母牛犊中有87%血清学呈阳性。1998年春季，49%的母牛和47%的小母牛犊仍呈阳性。1998年秋季，剩余母牛和小母牛中有48%血清学呈阳性。疫情爆发后的第一个繁殖季节（1998年）后，13.5%的小母牛和22.2%的母牛未怀孕（未受孕）。春季血清学呈阳性的动物在秋季更有可能未怀孕（优势比，2.0；95%置信区间，1.1至3.7）。未发现与流产、死产或未怀孕风险增加有后续关联。
