STUDIES ON THE EFFECTS OF INFECTIOUS BOVINE RHINOTRACHEITIS VIRUS ON REPRODUCTION IN HEIFERS

Natural venereal infection of heifers with IBR virus resulted in vulvovaginal lesions in 9 of 12 heifers at 3 weeks after introducttion to bulls, and virus was isolated from 5 of the 9 affected animals. The infection was not associated with any effect on conception. Experimental nasal and conjunctival infection of 18 heifers pregnant for 3, 5 or 7 months with a genital strain of IBR virus caused mild rhinitis or conjunctivitis in all inoculated animals and virus was recovered from 14 animals at 8 days after inoculation. No effects on pregnancy were recorded.     

牦牛病毒性腹泻/黏膜病和传染性鼻气管炎血清学调查

为掌握青海省大通种牛场和海晏县牦牛病毒性腹泻/黏膜病、传染性鼻气管炎的感染和流行情况,2010年3月至5月在大通种牛场和海晏地区采集252份牦牛血清样品,应用定量酶联免疫吸附试验（ELISA）对牦牛病毒性腹泻/黏膜病和传染性鼻气管炎的进行了血清抗体检测。结果显示,大通种牛场牦牛群中牛病毒性腹泻/黏膜病阳性率为23.42%,传染性鼻气管炎阳性率为65.45%;海晏县牦牛群中牛病毒性腹泻/黏膜病阳性率为19.86%,传染性鼻气管炎阳性率为4.96%。     

THE EFFECT OF NATURAL AND ARTIFICIAL BREEDING USING BULLS INFECTED WITH, OR SEMEN CONTAMINATED WITH, INFECTIOUS BOVINE RHINOTRACHEITIS VIRUS

Ten cows and heifers (Group B) were inoculated into the uterus at oestrus with semen followed by IBR virus for the first insemination and semen alone if a second insemination was necessary. All animals developed infectious pustular vulvo-vaginitis (IPV), and 2 cows conceived to the first and 2 to the second insemination (pregnancy rate of 40 percent requiring 4.5 services per conception). This group was compared with 10 control animals (Group A) which were treated similarly but received tissue culture fluid instead of virus at the first insemination. Group A had a pregnancy rate of 90 percent requiring 1.7 services per conception. Natural mating of 4 bulls with preputial infections due to infectious bovine rhinotracheitis (IBR) virus with 9 susceptible cows and heifers (group D), resulted in the production of lesions of IPV. The IPV infection did not affect their fertility (pregnancy rate of 89 percent requiring 1.4 services per conception) when it was compared to a similar group of females (group C) mated to the same bulls prior to infection with IBR virus (pregnancy rate of 100 percent requiring 1.2 services per conception). The 6 animals in Group B that were not pregnant and returned to oestrus 3 times were found on slaughter to have endometritis, salpingitis and vaginitis. A high incidence, 5 out of 18 (28 percent), of shortened oestrous cycles (less than 18 days) was a feature of the breeding pattern of this group. The undesirable consequences of distributing semen contaminated with IBR virus from artificial insemination centres are apparent.