School of Agriculture and Environment, Massey University, Palmerston North, New Zealand.
School of Veterinary Science, Massey University, Palmerston North, New Zealand.
Anim Reprod Sci. 2020 Mar;214:106312. doi: 10.1016/j.anireprosci.2020.106312. Epub 2020 Feb 6.
There is an epidemic in New Zealand of infectious bovine anaemia associated with Theileria orientalis Ikeda type, an obligate intracellular protozoan parasite. To establish whether T. orientalis Ikeda type infection adversely affects fertility of bulls used for natural mating, a randomised controlled experimental study was conducted. Ten of 17 2-year-old Friesian bulls that had not been previously infected with T. orientalis were infected with T. orientalis Ikeda type and then evaluations occurred during a 20-week period. There were semen and libido evaluations every 2 weeks, starting 4 weeks before the date of infection. In addition, there were blood collections, for haematocrit and infection intensity evaluations, rectal temperatures recorded, and bulls weighed three times weekly for 13 weeks after infection and then once weekly until completion of the study. Physical activity meters were also attached from Days 9-60 and 65-124 post-infection. The ten bulls were successfully infected with T. orientalis Ikeda type and this resulted in a decrease in HCT to about 0.25 by 70 days post-infection. There were no effects of infection on semen quality; however, during the acute phase of infection, when the infection intensity was rapidly increasing, the infected bulls took a longer time period for repeated mounting of females, and were less dominant in the herd social heiracrchy. In conclusion, although the transitory effects on libido could reduce conception rates, the overall effects of T. orientalis Ikeda type infection on bull fertility will probably be little.
新西兰正流行一种与东方泰勒虫 Ikeda 株相关的传染性牛贫血症，这种疾病由一种专性细胞内原生动物寄生虫引起。为了确定东方泰勒虫 Ikeda 株感染是否会对用于自然交配的公牛的生育能力产生不利影响，进行了一项随机对照实验研究。17 头 2 岁的弗里斯兰公牛中有 10 头从未感染过东方泰勒虫，它们被感染了东方泰勒虫 Ikeda 株，然后在 20 周的时间内进行评估。从感染前 4 周开始，每 2 周进行一次精液和性欲评估。此外，还进行了血液采集，用于评估血球比容和感染强度、直肠温度记录，并在感染后 13 周内每周称重 3 次，然后在研究结束前每周称重 1 次。从第 9 天到第 60 天和第 65 天到第 124 天，还安装了身体活动计。这 10 头公牛成功感染了东方泰勒虫 Ikeda 株，这导致它们的 HCT 在感染后 70 天左右下降到约 0.25。感染对精液质量没有影响；然而，在感染的急性期，当感染强度迅速增加时，受感染的公牛需要更长的时间才能重复地对雌性进行配种，并且在牛群的社会等级制度中地位较低。总之，尽管对性欲的短暂影响可能会降低受孕率，但东方泰勒虫 Ikeda 株感染对公牛生育力的总体影响可能很小。
