Lunstra D D, Coulter G H
USDA-ARS, Roman L. Hruska U.S. Meat Animal Research Center, Clay Center, NE 68933, USA.
J Anim Sci. 1997 Mar;75(3):767-74. doi: 10.2527/1997.753767x.
The infrared temperature pattern (IRT) of the scrotal surface was recorded for 73 yearling beef bulls and a color video thermogram of the pattern of each bull was recorded. The average scortal surface temperature, temperature at the top and bottom of the scrotum, scortal temperature gradient, and thermal class (normal, questionable, or abnormal scortal surface thermal pattern) were recorded for each thermogram. Thirty-seven bulls had a normal temperature pattern (51%), 20 had a questionable pattern (27%), and 16 had an abnormal temperature pattern (22%). Bulls exhibiting abnormal scrotal temperature patterns had lower (P < .05) percentages of sperm exhibiting normal head and tail morphology and had a higher (P < .01) percentage of sperm with proximal droplets than did bulls with normal or questionable thermogram patterns. Thirty bulls with acceptable testis size and semen quality and representing the three thermal classes were each exposed single-sire to approximately 18 heifers during a 45-d pasture breeding period. Pregnancy rate was lower (P < .01) for bulls with abnormal scrotal temperature patterns (68 +/- 4%, n = 8) than for bulls with normal (83 +/- 4%, n = 13) and questionable temperature patterns (85 +/- 4%, n = 9), and pregnancy rate was related significantly to all four major characteristics (surface, top, and bottom temperatures and temperature gradient) of scortal thermograms. Data indicated that bulls with abnormal scortal temperature patterns exhibited a reduced ability to maintain an effective thermal gradient from top to bottom of the testes and that bulls with abnormal scrotal temperature patterns achieved reduced pregnancy rates when used for natural mating.
记录了73头一岁肉用公牛阴囊表面的红外温度模式（IRT），并记录了每头公牛该模式的彩色视频热像图。记录了每个热像图的平均阴囊表面温度、阴囊顶部和底部的温度、阴囊温度梯度以及热类别（正常、可疑或异常的阴囊表面热模式）。37头公牛温度模式正常（51%），20头可疑（27%），16头异常（22%）。与温度模式正常或可疑的公牛相比，阴囊温度模式异常的公牛精子头部和尾部形态正常的百分比更低（P<0.05），近端液滴精子的百分比更高（P<0.01）。在45天的牧场配种期内，从代表三种热类别的睾丸大小和精液质量合格的30头公牛中，每头公牛单配约18头小母牛。阴囊温度模式异常的公牛受孕率（68±4%，n=8）低于温度模式正常（83±4%，n=13）和可疑的公牛（85±4%，n=9），且受孕率与阴囊热像图的所有四个主要特征（表面、顶部和底部温度以及温度梯度）显著相关。数据表明，阴囊温度模式异常的公牛维持睾丸从上到下有效温度梯度的能力降低，且用于自然交配时受孕率降低。
