May 10, 2022
Improving productivity of India's cattle through sex-sorted semen and embryo transfer
Dairy farmers in some Indian states, like Maharashtra, Odisha, Madhya Pradesh and Uttarakhand, can procure sex-sorted semen straws at a heavily subsidised price of ₹81 (US$1.05) per straw against a market value of ₹1,200 (US$15.53) per straw.
This is possible as India's state and central governments are subsidising significantly such straws, which will be manufactured by international animal genetics giants like ST Genetics and ABS Global.
By the law of probability, the chances of a female animal being born are equal to that of a male animal. The latter becomes a non-productive addition to the farmer's livestock.
As India has banned the culling of animals of cow progeny, the disposal of male animals becomes a problem for farmers. In relation to this issue, sex-sorting technology offers a mechanism to sort the semen, which would eliminate the probability of a male calf or filter Y chromosomes from the bull's sperm.
In the ten milk-producing districts of Maharashtra, dairy cooperative unions and private dairies would be paying ₹100 (US$1.29) per straw. With an artificial insemination (AI) charge of ₹41/dose (US$0.53), the effective rate to be paid by the farmer would be ₹81/straw (US$1.05). This would be the lowest price in the world for sex-sorted straws.
The proven advantages of sex-sorting in cattle production
Companies are producing sex-sorted semen from different breeds of cattle and buffaloes with an average of 93% female purity, exceeding all international and Indian quality standards. They are also proven in the field with a conception rate equal to or more than that of conventional semen under similar conditions, with the gender ratio of calves born averaging over 93% — which is consistent with laboratory gender purity.
Among the several methods for semen sexing, flow cytometry-based sorting has emerged as the most efficient. The technology is refined through the decades; thus, sex-sorting is finally possible at a purity of more than 90%. The technique is well standardised, patented and commercialised in the United States, Europe and other countries.
Other methods for the sex-sorting of sperm have also emerged, though these techniques need further fine-tuning for commercial viability.
Producing only female calves helps farmers to save resources that would have been shared with unwanted males. The production of more female calves will increase the supply of replacement heifers. This creates an opportunity to sell surplus heifers to other farms. It also expedites genetic improvement by increasing the efficiency of progeny testing programmes and boosting the efficiency of embryo transfer and in vitro fertilisation (IVF) programmes. Additionally, it is an economic way to increase herd strength with no risk of introducing diseases by purchasing heifers from outside.
As dead, dying or damaged sperm cells are removed during the sorting process, only viable sperm are available which helps the sexed semen to be successful even at a low concentration than conventional semen. By producing more female calves using sexed semen, there will be fewer difficult births compared to male calves. This is particularly true for maiden heifers.
There are a few limitations in terms of technology and implementation of the sex-sorted semen. Limitations lie in the high cost of a sex-sorting machine, low sorting efficiency and speed, a need for highly skilled staff to operate sex sorting machines, the wastage of approximately 50% of sperms and reduced freezing potential of sorted sperms. Furthermore, the conception rate with sex-sorted semen is 10-15% lesser than conventional semen. There is also no standard operating procedure to perform insemination with sexed semen.
In 2012, scientists from the National Dairy Research Institute produced a cattle calf using the Ovum-Pick-Up and IVF technology. This technology could be very useful for obtaining calves from dairy cattle that are infertile but still valuable. It could also be applied to those animals which do not respond to the conventional embryo transfer programme.
India's Animal Husbandry Ministry is now looking at creating 'cow factories' in which embryos and semen from superior breed cattle will be implanted into low-productive cows with the help of non-governmental organisations and the private sector. The aim is to improve breeding and productivity as well as create disease-free cattle at a faster rate.
In another development, successful IVF trials were conducted by the National Dairy Development Board in collaboration with Brazil's EMBRAPA Dairy Cattle. Productivity and breeding that could not have been realised in seven generations of cattle are now going to be achieved in one generation.
The Indian government is also allowing universities, livestock development boards and industry players to develop embryos and sell them to farmers. Under the Accelerated Breed Improvement Programme, a target of two lakh embryos has been set up for the next three years. Every farmer will be given a subsidy of ₹5,000 (US$64.73) for each successful pregnancy.
- Dr. Dinesh Bhosale