Survival and Development of in Vivo Produced Boran and Boran* Holstein Cross Embryos

Abstract

One of biotechnology technique that is frequently used to enhance the number of animals with superior genetic ability and high productivity is embryo transfer. Embryos can be obtained in vivo or in vitro, and they can be frozen and then thawed before being delivered to the recipient animals. Conception rates are influenced by a number of variables, including the quality and developmental stage of the embryo, the location of the embryo's deposit in the uterus, the degree of difficulty of the transfer, whether to use a fresh or frozen embryo, the operator's experience, the corpus luteum's quality, whether to use a heifer or a cow, and the time of year the transfer occurs. The fertility of domestic animals is severely impacted by early embryonic death. For this reason, this study was carried out to gather data on early embryonic development that is normal, the amount and timing of embryonic mortality, potential endogenous and exogenous causes of embryonic loss, and to develop strategies to lower embryonic mortality. A total of 40 embryos (20 fresh and 20 frozen, 26 quality grade 1 and 14 quality grade 2, 29 compact Morula stage and 11 early Blastocyst stage) were transferred to 40 recipient cows (22 Boran and 18 H-B cross) with different body condition score. Return to heat was used as method of pregnancy diagnosis and all recipients were followed around day 14 post embryo transfer and 14 animals were shown heat sign, the rest 26 animals were suspected for pregnancy (65%). Using ultrasound, a pregnancy diagnosis was made on day 45, and 20 recipient animals were found to be 50% positive for PD. On day 60, PD positive animals were re-examined with ultrasound and only 10 were confirmed as PD positive (25%). The PD negative on day 45 and day 60 were suspected to be early embryonic mortality. Other pregnancy loss occurred in this study was abortion nearly after five month of pregnancy. It is not doubtful that, the technique of embryo transfer is utilized to increase the reproductive rates of important female animals. However, it needs proper management for both donor and recipient animals. Therefore, for the successful application of the technology optimum level of feeding both quantity and quality, health management and conducive environment should be fulfilled for all animals.