Pregnancy rate is low in artificial insemination with sexed semen compared to conventional semen. This situation poses a major problem for dairy farms. The aim of this study was to determine the effects of semen type on conception rate, calf sex and birth weight, stillbirth, pregnancy loss, and postpartum maternal body weight (MBW) in Holstein heifers inseminated with sexed (n = 229), and conventional semen (n = 153). The female and male calf ratios of the heifers inseminated with sexed and conventional semen were found to be 88% to 54.8% and 12% to 45.2%, respectively. There was a significant difference between sperm type and calf sex (p < 0.001). While 36.7% of calves between 34 and 36 kg birth weights were born from heifers inseminated with sexed semen, 15.7% were born from heifers inseminated with conventional semen. Moreover, 46% and 17.3% of calves that had birth weights of 36.1-38.1 kg and > 38.2 kg were born from heifers inseminated with sexed semen while 40% and 44.3% were born from heifers inseminated with conventional semen, respectively. A statistically significant relationship was found between semen type and calf birth weights (p < 0.001). After calving, there was a significant difference between semen type and MBW after calving (p < 0.001). In the sexed and conventional semen groups, the MBW after calving was found to range from 11.3% to 23.5% in the 400-460 kg, 46.7% to 57.4% in the 461-511 kg, and 42% to 19.1% in the 512-587 kg weight categories, respectively. There was no statistically significant difference (p > 0.05) between sperm type and mean gestation length and calf birth weight, pregnancy loss, stillbirth rate, and weaning calf mortality rates. There was a strong positive correlation between semen type, sex, and calf birth weight. Furthermore, there was a significant correlation between the MBW, the gestation period and the survival status of the calves. It was determined that there was a minor positive relationship between the insemination season and the gestation period, MBW, and the survival status of the calves. Our results demonstrated that with careful and consistent application of herd management program in dairy cattle farms, the rates of pregnancy obtained with sexed and conventional semen will increase, whilst parameters such as stillbirth and pregnancy loss will decrease.
Calf sex, conception rate, maternal body weight, sexed semen, stillbirth
"Effects of use of conventional and sexed semen on conception rate, calf sex, calf birth weight, and stillbirth in Holstein heifers,"
Turkish Journal of Veterinary & Animal Sciences: Vol. 47:
2, Article 3.
Available at: https://journals.tubitak.gov.tr/veterinary/vol47/iss2/3