Kareskoski Maria, Venhoranta Heli, Virtala Anna-Maija, Katila Terttu
University of Helsinki, Faculty of Veterinary Medicine, Paroninkuja 20, 04920, Saarentaus, Finland.
University of Helsinki, Faculty of Veterinary Medicine, PO Box 66, 00014, Helsinki, Finland.
Theriogenology. 2019 Mar 15;127:7-14. doi: 10.1016/j.theriogenology.2018.12.036. Epub 2019 Jan 2.
Artificial insemination (AI) with cooled stallion semen has increased markedly during the last decades in all countries, but fertility is often lower than when fresh semen or natural mating is used. The objective of this study was to examine field data (1634 ,cycles 523 Standardbred (SB) mares, 575 Finnhorse (FH) mares, and 90 stallions) using multivariable logistic regression for factors influencing the pregnancy rate (PR) after AI with cooled transported semen from SB and FH stallions. The PR per cycle for the material was 47%: Finnhorses 42% and Standardbreds 53%. When assessed with multivariable logistic regression analyses with a generalized linear mixed model, variables that affected the PR were breed, the number of inseminated estrus cycles, the percentage of progressively motile sperm (PMOT) in the ejaculate/AI dose at the time of shipment, and the number of progressively motile sperm in the AI dose at the time of insemination. In Standardbreds, variables that increased the per cycle PR were the number of AI per estrus cycle (multiple inseminations increasing the probability of pregnancy compared to only one insemination), the number of inseminated cycles, and PMOT in the AI dose at the time of insemination. In Finnhorses, the number of AI per estrus cycle (two and three inseminations increasing the probability of pregnancy compared to only one), the number of spermatozoa in the ejaculate and in the AI dose, and PMOT in the ejaculate/AI dose at the time of shipment increased the per cycle PR. Non-significant factors for the whole material included the type of artificial vagina (open-ended or closed), transport time, place of AI (stud farm or home stable), insemination done by veterinarian or technician, weekday, month, age of the mare (all age classes combined), age of the stallion, ejaculate parameters (sperm concentration, total number of sperm), and insemination dose parameters (volume proportion of seminal plasma, sperm concentration, PMOT, total number of sperm). In conclusion, breed, breeding opportunity in more than one cycle, more than one insemination/estrus, PMOT of the ejaculate/AI dose and the number of progressively motile sperm in the AI dose at the time of insemination are important for the outcome of inseminations with cooled semen.
在过去几十年里，所有国家使用冷藏种马精液进行人工授精（AI）的情况都显著增加，但与使用新鲜精液或自然交配相比，其受胎率往往较低。本研究的目的是利用多变量逻辑回归分析，对1634个周期（涉及523匹标准赛马（SB）母马、575匹芬兰马（FH）母马和90匹种马）的现场数据进行分析，以探讨影响用来自SB和FH种马的冷藏运输精液进行人工授精后妊娠率（PR）的因素。该材料每个周期的妊娠率为47%：芬兰马为42%，标准赛马为53%。当采用广义线性混合模型进行多变量逻辑回归分析评估时，影响妊娠率的变量包括品种、授精发情周期数、装运时射精/人工授精剂量中渐进性活动精子（PMOT）的百分比，以及人工授精时人工授精剂量中渐进性活动精子的数量。在标准赛马中，每个周期妊娠率增加的变量包括每个发情周期的人工授精次数（与仅进行一次授精相比，多次授精增加了怀孕的概率）、授精周期数，以及人工授精时人工授精剂量中的PMOT。在芬兰马中，每个发情周期的人工授精次数（与仅进行一次相比，两次和三次授精增加了怀孕的概率）、射精和人工授精剂量中的精子数量，以及装运时射精/人工授精剂量中的PMOT增加了每个周期的妊娠率。对于整个材料而言，无显著影响的因素包括人工阴道类型（开放式或封闭式）、运输时间、人工授精地点（种马场或家庭马厩）、由兽医或技术人员进行人工授精、工作日、月份、母马年龄（所有年龄组综合）、种马年龄、射精参数（精子浓度、精子总数），以及人工授精剂量参数（精浆体积比例、精子浓度、PMOT、精子总数）。总之，品种、在多个周期的繁殖机会、每个发情期多次授精、射精/人工授精剂量的PMOT以及人工授精时人工授精剂量中渐进性活动精子的数量，对于冷藏精液人工授精的结果很重要。
