Multiple Ovulation and Embryo Transfer | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

Multiple Ovulation and Embryo Transfer

• Artificial insemination has significantly benefited the cattle industry by enhancing reproduction techniques.
• Recent advancements in reproduction manipulation, such as controlling the estrus cycle, have been crucial.
• Embryo transfer has emerged as a key technique for accelerating progress in cattle breeding.

Embryo Transfer Technology

Selection of Donor:

• Donors are chosen based on criteria such as age, genetic health, regular estrous cycles, and reproductive performance.
• Selection ensures the production of high-quality embryos.

Superovulation:

• Superovulation involves inducing multiple ovulations using hormonal treatments.
• Gonadotropic hormones like PMSG and FSH are commonly used for this purpose.
• It aims to maximize the maturation of follicles for embryo production.

Embryo Collection:

• Non-surgical methods are preferred for embryo collection in cattle to avoid reproductive tract damage.
• Embryos are collected around 6-8 days after estrus using techniques like the continuous flow or interrupted-syringe method.
• Embryos are evaluated based on quality and development stage before transfer.

Embryo Evaluation and Handling

• Embryos are assessed for viability based on size, development stage, and cellular appearance.
• Quality classification (good, moderate, poor) correlates with pregnancy success post-transfer.
• Embryos can be stored and cultured for a certain period before transfer without significant loss of viability.

Conclusion

• Multiple ovulation and embryo transfer techniques have revolutionized cattle breeding by enhancing genetic selection and reproductive efficiency.
• These advancements have allowed for increased offspring from superior parent stock without compromising reproductive performance.

Embryo Transfer to Recipients:

• Recipient suitability for embryo transfer is influenced by various factors such as the health and fertility of the animals (preferably fertile heifers or young cows) in good body condition, capable of delivering the calf without complications at term.
• It is crucial for the oestrous cycles of both the donor and recipient to be synchronized closely to enhance the survival chances of transferred embryos. A deviation of more than 24 hours significantly reduces the pregnancy rate.
• Proper placement of the embryo in the uterine horn on the same side as the corpus luteum is essential for higher pregnancy rates.
• Embryos can be transferred either surgically or non-surgically, with success rates being influenced by the skill of the individual performing the transfer.

Cryopreservation of Embryos:

• The development of cryopreservation has revolutionized embryo transfer by enabling freezing and storage of bovine embryos at ultra-low temperatures, typically -196°C, for varying durations.
• Success rates in terms of pregnancies resulting from frozen embryos range from 16% to 60%, depending on factors such as the freezing method, cryoprotectant used, and the transfer technique.
• Glycerol is commonly used as a cryoprotectant in cryopreservation, but it must be added gradually to prevent cellular injury from osmotic trauma.
• Various techniques such as programmed freezing machines and vitrification are employed to ensure optimal embryo survival during the cryopreservation process.

Usefulness of Embryo Transfer Technology in Cattle:

• Exploitation of superior females by increasing offspring production.
• Complete control over the genotype of the embryo.
• Reduction of the generation interval.
• Facilitation of long-term cryopreservation and transportation of livestock between countries in the form of embryos.
• Rapid multiplication of endangered, rare, and commercially valuable breeds.
• Production of offspring from heifers at a young age.
• Utilization as a research tool for studying genetic defects and reproductive physiology.
• Requires highly motivated and experienced staff, along with significant capital investment in facilities, equipment, drugs, and quality animals for successful implementation.