Quality Cattle - Assisted Reproduction Technology

The way domestic cattle are used for milk production has been changing during the last decades. New biotechnologies have been created and applied to the cattle industry to increase the efficiency of dairy production systems. Among these technologies are those involved in assisted reproduction.  

 

Assisted reproductive technology(ART) includes medical procedures used primarily to address infertility. When used to address infertility, ART may also be referred to as fertility treatment. ART mainly belongs to the field of reproductive endocrinology and infertility. ART may also be used in surrogacy arrangements, although not all surrogacy arrangements involve ART. The ultimate aim of assisted reproductive technologies (ART) is to birth healthy offspring and desired offspring. This subject involves procedures such as Embryo Transfer (MOET), in vitro fertilization (IVF), cryopreservation of gametes or embryos,  Sexed Semen Technology, and/or the use of fertility medication.

 

 

Embryo Transfer (MOET):

 

Also called Multiple Ovulation and Embryo Transfer (MOET) Technology, it is used to increase the reproduction rate of superior female dairy animals. Typically, one can get one calf from superior female dairy animals in a year. But by using MOET technology, one can get 10-20 calves in a year from a cow/buffalo. An elite cow/buffalo is administered hormones with FSH-like activity to induce super-ovulation. Under the influence of the hormone, the female produces several eggs instead of one egg produced normally. The super-ovulated female is inseminated 2-3 times at 12-hour intervals during oestrus, and then its uterus is flushed with medium 7th-day post insemination to retrieve the developing embryos. Embryos are collected along with a flushing medium in a specialized filter, and the quality of the embryo is assessed under the microscope. Good quality embryos are either frozen and preserved for transfer in the future or transferred fresh into recipient animals approximately seven days post heat date. Thus, from an elite dairy animal, several calves can be produced in a year. 

The first embryo transfer technology (ETT) project in the country was initiated by NDDB in 1987 by the establishment of a central ET laboratory at Sabarmati Ashram Gaushala (SAG), Bidaj. The first buffalo calf of India from a frozen-thawed embryo was born in the year 1991. 

 

 

In- Vitro Fertilization (IVF) Technology:

 

Also called Ovum Pick-up and In Vitro Embryo Production (OPU-IVEP) Technology, is an advanced reproductive technology for the multiplication of superior female germplasm faster. Using MOET technology, one can get 10-20 calves from an excellent female dairy animal in a year. But by using OPU-IVEP technology, one can get 20-40 calves in a year from a cow/buffalo.

NDDB has produced more than eight hundred cattle IVF embryos using sexed or conventional semen established more than 50 pregnancies from fresh and frozen IVF embryos, and produced several IVF calves.

Another essential job at hand is to standardize and optimize the technology in buffaloes, as very little work has been done on buffaloes. 

Using this technology, embryos are produced in vitro, i.e., inside the laboratory instead of in a womb/ uterus. During the OPU-IVEP procedure, oocytes are aspirated from the ovarian follicles non-surgically by an ultrasound-guided aspiration device through the vaginal wall. A vacuum system is used to recover the contents of follicles. Once follicles are aspirated from ovaries, the aspirated follicular fluid and ovum pick-up medium is passed through an appropriate filter to remove excess fluid, blood, and cell debris. Then the fluid is poured into a petri dish, and oocytes are searched under the microscope. Oocytes are selected based on the cumulus cell layers for further processing. The selected oocytes are washed and incubated inside the specialized CO2 incubator in vitro maturation medium for 20-22 hours. This process is called in vitro maturation (IVM). After 20-22 hours, oocytes are again assessed under the microscope for quality of maturation. Then the matured oocytes are incubated with the processed sperms in vitro fertilization medium for 18 hours in the same incubator. This process is called in vitro fertilization (IVF). The resulted in presumptive zygotes after denudation and washing incubated in vitro culture medium in a specialized mix gas incubator for seven days from IVF. This process is called in vitro culture (IVC). Similar to traditional embryo transfer programs, the quality of embryos is assessed under the microscope, and good quality embryos are either frozen or transferred into suitable recipient/surrogate animals that were in oestrus seven days ago. 

 

 

Sexed Semen Technology:

 

 

Semen having either X or Y bearing sperm to produce progenies of the desired sex, i.e., female or male, is known as sexed semen. The technologies presently available are capable of producing sexed semen with 80-90 percent accuracy. By adopting this technology, dairy farmers can produce progenies of desired sex and abate the menace of unwanted stray male animals. The full potential of this technology can be appreciated if combined with IVF for the production of sexed embryos as oocytes from multiple donors can be fertilized using single-sexed semen doses. 

 

 Concluding Remarks:

Several ART has been applied in the cattle industry. Some have provided acceptable results, but others have low efficiency, limiting their use for cattle breeding. Among the ET technologies, MOET is the most efficient so far. Improvements in OPU/ IVF programs would have a tremendous economic impact on the cattle industry and overtake traditional MOET programs. Embryo and sperm sexing are already at a commercial level with acceptable results. Improvements in the sorting of sperm will make this biotechnology more acceptable and might overtake embryo sexing.

 

Author: Priya Parashar
Sr. Sales and Marketing Executive
Pashushala.com
Uplifting livestock economy.