Murphy E M, Eivers B, O'Meara C M, Lonergan P, Fair S
Laboratory of Animal Reproduction, Department of Biological Sciences, School of Natural Sciences, Faculty of Science and Engineering, University of Limerick, Limerick, V94 T9PX, Ireland; National Cattle Breeding Centre, Naas, Co Kildare, W91 WF59, Ireland.
National Cattle Breeding Centre, Naas, Co Kildare, W91 WF59, Ireland.
Theriogenology. 2018 Mar 1;108:223-228. doi: 10.1016/j.theriogenology.2017.12.012. Epub 2017 Dec 7.
The aim of this study was to assess the effect of storage temperature, nitrogen (N) gassing and sperm concentration on in vitro characteristics and calving rate (CR) following artificial insemination (AI) of liquid bull semen stored in INRA96. In Experiment 1 the effect of liquid bull semen diluted in either N bubbled or non-bubbled INRA96 at a concentration of 5 × 10 sperm per 0.25 mL insemination dose and stored at 5 or 15 °C was assessed subjectively for total and progressive motility on Days 0, 1, 2, 3 and 4 post collection. In Experiment 2a, the effect of stored liquid semen at three sperm concentrations (3, 4 or 5 × 10 sperm per 0.25 mL insemination dose) on total and progressive motility was assessed subjectively on Days 0, 1 and 2 post collection. In Experiment 2b, the field fertility of liquid semen stored at ambient temperature at a concentration of 3, 4 or 5 × 10 sperm per 0.25 mL dose and inseminated on Days 1 or 2 post collection was assessed in comparison to frozen-thawed semen (total of n = 5742). In Experiment 1, total and progressive motility decreased with increased duration of storage (P < 0.01); however, there was no effect of N bubbling on motility on Days 0, 1, 2, 3 and 4 of storage. There was an effect of temperature on total and progressive motility, regardless of treatment, as semen stored at 15°C recorded higher motility values than semen stored at 5°C (P < 0.01). In Experiment 2a, there was no effect of sperm concentration on total or progressive motility on Days 0, 1 or 2 of storage. There was a linear decrease in motility with increased duration of storage (P < 0.01); however, there was no sperm concentration by day interaction. In Experiment 2b, there was an effect of sperm concentration on CR (P < 0.01); semen diluted to 3 and 4 × 10 sperm per dose resulted in a lower CR after 2 days of storage (41.1 and 44.7%, respectively) in comparison to frozen-thawed semen (55.2%) but did not differ to CR of semen diluted to 5 × 10 sperm per dose on Day 2 of storage. There was an effect of parity, fertility sub-index and days in milk (DIM) at AI on CR (P < 0.01). In conclusion, N bubbling and sperm concentration had no effect on in vitro sperm motility of liquid semen, but this study demonstrated a reduction in CR on Day 2 of storage at lower sperm concentrations in comparison to frozen-thawed semen.
本研究旨在评估储存温度、氮气（N）充气和精子浓度对储存在INRA96中的液态公牛精液人工授精（AI）后的体外特征和产犊率（CR）的影响。在实验1中，主观评估了以每0.25 mL授精剂量5×10个精子的浓度稀释于通气或未通气的INRA96中的液态公牛精液，在采集后第0、1、2、3和4天的总活力和前向运动活力，精液分别储存于5℃或15℃。在实验2a中，主观评估了储存的液态精液在三种精子浓度（每0.25 mL授精剂量3、4或5×10个精子）下，在采集后第0、1和2天的总活力和前向运动活力。在实验2b中，将储存于室温下、每0.25 mL剂量浓度为3、4或5×10个精子且在采集后第1或2天进行授精的液态精液的田间生育力与冻融精液（总共n = 5742）进行了比较。在实验1中，总活力和前向运动活力随储存时间延长而降低（P < 0.01）；然而，在储存的第0、1、2、3和4天，氮气充气对活力没有影响。无论处理如何，温度对总活力和前向运动活力均有影响，因为储存在15℃的精液活力值高于储存在5℃的精液（P < 0.01）。在实验2a中，精子浓度对储存第0、1或2天的总活力或前向运动活力没有影响。活力随储存时间延长呈线性下降（P < 0.01）；然而，不存在精子浓度与天数的交互作用。在实验2b中，精子浓度对产犊率有影响（P < 0.01）；与冻融精液（55.2%）相比，每剂量稀释至3和4×10个精子的精液在储存2天后产犊率较低（分别为41.1%和44.7%），但在储存第2天与每剂量稀释至5×10个精子的精液的产犊率没有差异。胎次、生育力子指数和人工授精时的泌乳天数（DIM）对产犊率有影响（P < 0.01）。总之，氮气充气和精子浓度对液态精液的体外精子活力没有影响，但本研究表明，与冻融精液相比，较低精子浓度下储存第2天的产犊率有所降低。
