Updated: November 25, 2020 8:58:45 am
An Oxford Vaccine Group researcher in a laboratory in Oxford, England, is working on the coronavirus vaccine developed by AstraZeneca and the University of Oxford. (AP)
As various COVID-19 vaccines prepare to hit the market, concerns have been raised about an adequate cold chain infrastructure across the country to maintain the integrity of these live / inactivated viruses or DNA / RNA genetic material. But legislators and public health professionals can probably learn a lesson or two from the dairy industry here. And no, it is not about the transport and storage of milk, butter, curd or ice cream at low or sub-zero temperatures, but bull semen.
Almost 8 million rupees of artificial inseminations (AI) are performed annually in India. These AIs involve the transport of semen, collected as raw ejaculate from elite bulls and packaged after freezing in vials or “straws”, for insertion into the reproductive tracts of cows and buffaloes. This semen, which comes from animals in 56 bull stations and is used to inseminate female cattle belonging to farmers throughout the country, is kept throughout its journey at minus 196 degrees Celsius. This is much lower than the minus 20 to minus 70 degree requirements of Moderna and Pfizer Covid vaccines!
The reasons for cold chain requirements at extreme freezing temperatures for AI semen are the same as for vaccines. Sperm or male genetic material from fresh bull semen will lose their viability at normal room temperature within 15 minutes of collection. Therefore, the 5 ml or more of semen from each ejaculation is first diluted enough to fill up to 250 “straws”, each with 0.25 or 0.5 ml of solution. The straws are then sealed and printed with the details of the donor bull, the date of collection / filling, etc. After printing, the straws are frozen by immersing them in containers of liquid nitrogen. These containers, typically 35 liters (with 2,500 straws) or 48 liters (15,000 straws) capacity, are transported from bull stations to different parts of India.
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“Liquid nitrogen (produced by compressing and cooling nitrogen gas below its evaporation / boiling point, which is minus 195.79 degrees Celsius) is the most important ingredient in our cold chain. It ensures that the frozen straws are kept at the required temperatures even seconds before being used to inseminate the female at the farmer’s door, ”explains Ashok Pande, group vice president (Scientific Research and Livestock Development) at BAIF Development Research Foundation.
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With 300 active bulls at its two stations in Urulikanchan in the Pune district and Dharouli in Jind (Haryana), BAIF produces around 45 lakh of semen straws every year. That makes it the second-largest in India after the National Dairy Development Board, which runs four semen stations in Bidaj (Gujarat), Salon (Uttar Pradesh), Alamadhi (Tamil Nadu) and Rahuri (Maharashtra) which in Together they deliver about 380 lakh doses per year. Bulls kept at bull stations are animals whose female parent (“mother”) has had a superior lactation history. By injecting the semen extracted from these progeny tested bulls into farmers’ cows, you would increase their milk production. This AI-mediated breeding and breeding program for cattle and buffalo, which has been underway for the past 50 years, is what has led India to emerge as the world’s largest dairy producer.
In 2018-19, a total of 787.48 AIs were conducted in India, of which 360.55 lakh were by state animal husbandry departments (AHD), 189.85 lakh by dairy cooperatives and 242.08 lakh by other agencies. The AIs are performed by paraveterinarians, who source the 135mm long straws from the jumbo containers that receive the AHDs / dairies filled into smaller 3-liter containers. Paraveterinarians insert the frozen semen doses after thawing them for a few seconds using specially made AI guns. Insemination is performed at the farmer’s door when the female is at the peak of her “heat” or estrus cycle which occurs every 20-21 days.
“The 3-liter container (which has about 720 straws) is the real reason for the success of India’s AI and miscegenation program. Unlike the US or Europe, where inseminators travel to farms in their cars, our paraveterinarians needed smaller containers that could be attached to two-wheelers going to the most remote villages, ”says Pande.
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All of this, of course, has been backed by an efficient cold chain system, about which not much has been written. The refrigerant used (liquid nitrogen from chemical fertilizer units or liquid oxygen plants, which produce it as a by-product) and straw filling machines are established technologies for dairymen.
“The most crucial aspect of the AI cold chain is its reliability (ensuring the viability of sperm from the point of semen extraction to injection into a female bovine) and its reach (to distant interiors). I am sure this may be of some relevance to the national launch of the Covid vaccine, “says Rajiv Mitra, CEO of Sunfresh Agro Industries Pvt Limited, based in Ahmednagar, Maharashtra. This dairy, which is part of the French Lactalis Group, produces approximately 1 lakh of AI per year. There are others, like Gujarat’s Kaira District Dairy Cooperative Union (Amul Dairy), who make more than 10 lakh AI a year. “
Mitra’s dairy currently has 50 centers, from where its paraveterinarians collect BAIF straws in 3-liter containers. These inseminators come to the centers every three days to replenish both the straws and the liquid nitrogen in their containers.
“Every time the container is opened, liquid nitrogen escapes. We maintain a reserve stock of liquid nitrogen in our centers, from where inseminators can refill it. The process is not very complicated ”, adds Mitra.
That lack of complications can be of some guarantee when the country is looking for viable cold storage solutions in something other than bull semen.
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