Ingenhoff L, Hall E, Ranjbar Ni S, House J K
Livestock Veterinary Teaching and Research Unit, Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, New South Wales, Australia.
Faculty of Veterinary Science, School of Life and Environmental Sciences, The University of Sydney, Camden, NSW, Australia.
Aust Vet J. 2017 Sep;95(9):317-324. doi: 10.1111/avj.12621.
To determine if insemination site or pre-ovulatory follicle diameter at fixed-time artificial insemination (FTAI) affects the odds of pregnancy when heifers are inseminated with sexed semen.
The study was conducted in 422 Holstein heifers enrolled into 531 inseminations. Inseminations were randomly allocated to 1 of 16 treatment combinations involving three variables: semen type (sexed vs non-sexed), insemination site (uterine horn vs uterine body) and one of four sires. Ovaries were examined by transrectal ultrasound prior to FTAI to determine the follicle diameter and location. AI technician, times bred, age, weight and temperature-humidity index were also recorded. Pregnancy diagnosis was conducted 29 days post-insemination. Follicle diameter and body weight were categorised according to arbitrary cut-points. Each variable was analysed by logistic regression to determine the effect on pregnancy per AI and compare between sexed and non-sexed inseminations.
Insemination site did not affect pregnancy per AI for either sexed (P = 0.528) or non-sexed (P = 0.886) inseminations. Heifers with an 18-22 mm follicle had better odds of pregnancy than heifers that did not (odds ratio (OR) 1.45, 95% confidence interval (CI) 1.004-2.09), although no effect was detected for only sexed or only non-sexed inseminations. Heifers weighing 310-370 kg had a higher pregnancy per AI than heifers weighing > 370 kg for non-sexed inseminations (P = 0.004) and sexed semen from sire 4 caused lower odds of pregnancy than semen from sire 1 (OR 0.40, 95% CI 0.18-0.89).
Insemination site did not affect pregnancy per AI, but heifers with an 18-22 mm pre-ovulatory follicle at insemination had better odds of pregnancy for both sexed and non-sexed inseminations.
确定在定时人工授精（FTAI）时授精部位或排卵前卵泡直径对用性控精液对小母牛进行人工授精后的妊娠几率是否有影响。
本研究对422头荷斯坦小母牛进行了531次人工授精。人工授精被随机分配到16种处理组合中的一种，涉及三个变量：精液类型（性控精液与非性控精液）、授精部位（子宫角与子宫体）以及四个公牛之一。在FTAI前通过直肠超声检查卵巢，以确定卵泡直径和位置。还记录了人工授精技术员、配种次数、年龄、体重和温湿度指数。在授精后29天进行妊娠诊断。卵泡直径和体重根据任意切点进行分类。通过逻辑回归分析每个变量，以确定对每次人工授精妊娠的影响，并比较性控精液和非性控精液人工授精之间的差异。
授精部位对性控精液（P = 0.528）和非性控精液（P = 0.886）的每次人工授精妊娠率均无影响。卵泡直径为18 - 22毫米的小母牛比未达到此标准的小母牛妊娠几率更高（优势比（OR）1.45，95%置信区间（CI）1.004 - 2.09），不过仅对性控精液或仅对非性控精液人工授精未检测到影响。对于非性控精液人工授精，体重在310 - 370千克的小母牛每次人工授精的妊娠率高于体重> 370千克的小母牛（P = 0.004），并且来自公牛4的性控精液导致的妊娠几率低于来自公牛1的精液（OR 0.40，95% CI 0.18 - 0.89）。
授精部位不影响每次人工授精的妊娠率，但在授精时排卵前卵泡直径为18 - 22毫米的小母牛，无论是性控精液还是非性控精液人工授精，妊娠几率都更高。
