Akhtar S, Mirza M A
Animal Sciences Institute, National Agricultural Research Centre, Islamabad, Pakistan.
Rev Sci Tech. 1995 Sep;14(3):711-8. doi: 10.20506/rst.14.3.861.
The authors estimated the rates of development of serum antibodies against Brucella abortus, between January 1987 and December 1990, in female Jersey cattle and buffalo weaned from seropositive and seronegative dams, and used logistic regression analysis to examine the epidemiological relationship of these rates with the serum antibody status of dams. The offspring from both seropositive and seronegative dams were reared together in calf pens, while separate pens were used for bovine and buffalo calves. Each of the bovine calves was manually fed two litres of bulked milk (pooled from seronegative and seropositive cows) twice a day, in the morning and evening. The buffalo calves, however, were allowed to suckle their respective dams before and after manual milking of each buffalo, in the morning and evening. Bovine calves and buffalo calves were weaned at approximately six months of age and moved to sheds for young livestock. At maturity, the female offspring were artificially inseminated, and pregnancy was subsequently diagnosed by rectal palpation. The rate of seroconversion in the progeny of seropositive Jersey cattle was 26.4% (14 of 53 animals) compared to 14.3% (11 of 77 animals) in the progeny of seronegative cattle; this difference was non-significant (P = 0.1342). In buffalo, however, the rate of seroconversion in the progeny of seropositive dams (43.3% = 13/30) was significantly higher (P = 0.0002) than in the progeny of seronegative buffalo (8.8% = 6/68). The logistic regression analysis revealed that the progeny of seropositive buffalo were approximately 6.2 times more likely to have developed serum antibodies by the time of first calving than the progeny of seronegative buffalo (adjusted odds ratio [OR]) = 6.2; 95% confidence interval [CI] = 1.5, 36.4). This relationship was non-significant, however, for the progeny of seropositive cattle (adjusted OR = 2.1; 95% CI = 0.6, 7.4). The implications of these results and potential sources of bias are discussed.
作者估算了1987年1月至1990年12月期间，从血清学阳性和血清学阴性的母畜断奶的泽西奶牛和水牛中抗流产布鲁氏菌血清抗体的产生率，并使用逻辑回归分析来检验这些比率与母畜血清抗体状态之间的流行病学关系。血清学阳性和血清学阴性母畜的后代在犊牛栏中一起饲养，而牛犊和水牛犊则分别使用单独的栏舍。每头牛犊每天早晚各人工饲喂两升混合牛奶（从血清学阴性和血清学阳性奶牛中收集）。然而，水牛犊在每天早晚人工挤奶前后，可吸吮各自的母畜。牛犊和水牛犊大约在六个月大时断奶，并转移到幼畜棚中。成年后，雌性后代进行人工授精，随后通过直肠触诊诊断怀孕情况。血清学阳性泽西奶牛后代的血清转化率为26.4%（53头中有14头），而血清学阴性奶牛后代的血清转化率为14.3%（77头中有11头）；这种差异不显著（P = 0.1342）。然而，在水牛中，血清学阳性母畜后代的血清转化率（43.3% = 13/30）显著高于血清学阴性水牛后代（8.8% = 6/68）（P = 0.0002）。逻辑回归分析显示，血清学阳性水牛的后代在首次产犊时产生血清抗体的可能性比血清学阴性水牛的后代高约6.2倍（调整后的优势比[OR] = 6.2；95%置信区间[CI] = 1.5, 36.4）。然而，对于血清学阳性奶牛的后代，这种关系并不显著（调整后的OR = 2.1；95% CI = 0.6, 7.4）。讨论了这些结果的意义和潜在的偏差来源。
