Low dose insemination in cattle with the Ghent device

In each of three field trials, the cows (n = 795, 659, 360) and heifers (n = 253, 182, 231) were randomly assigned to receive 12 million sperm deposited in the uterine body using conventional techniques (control) or a reduced sperm dose (RSD) deposited in the same manner as the control or bilateral deposition near the uterotubal junction using the Ghent device (Ghent). Sperm dosages for RSD and Ghent inseminations were 8, 4, and 2 million sperm for field trials 1-3, respectively. In the multivariable analysis, the pregnancy rates were significantly affected by the parity of the cow (p ≤ 0.008) in each of the three trials, by the sire (p = 0.014, 0.009) in trials 1 and 3, and by the inseminator (p < 0.001) in trial 2. In none of the trials were the pregnancy rates significantly affected by the insemination technique, the order of insemination (first, second, or third), the breed of the bull or the dosage sensitivity of the bull. In conclusion, neither sperm dosage nor site of semen deposition influenced pregnancy rates in the present study.