my country's first batch of somatic cell cloned excellent dairy cows born
◎Reporter Wang Yingxia and correspondent Xun Xiaoyun
The birth of "Dolly" the sheep made cloning technology widely known.
27 years later, the Chinese used it for the rapid breeding of fine-bred dairy cows.
On January 31, the Ningxia Department of Science and Technology officially announced that before the Spring Festival, three high-yield and long-lived cows were born in Lingwu City using somatic cell cloning technology. 100 tons of high-quality Holstein cows were used for germplasm restoration and preservation and breeding.
"These cloned cows are the core members of the 100-ton star dairy cow group, and they are also the core resources for cultivating improved dairy cows with their own intellectual property rights, which is a key step towards solving the related 'stuck neck' problem." Director of the Rural Science and Technology Department of the Ningxia Science and Technology Department Xu Xiaotao said.
High-yield and long-lived dairy cows reborn in Ningxia
Improved breeds are the "chips" of the breeding industry. However, the indisputable reality is that my country's dairy cows rely on foreign countries for as much as 70%.
Looking at the domestic dairy cow population, excellent dairy cows with good adaptability, a lifetime milk output of more than 100 tons, and a total production performance index of more than 2400 are precious resources for breeding, but the total amount is less than 5/10,000, and the distribution is very scattered.
In 2021, with the support of the Ningxia Science and Technology Department and the Lingwu Municipal Government, the dairy cow breeding innovation team of Northwest Agriculture and Forestry University will launch related projects in the Lingwu Dairy Cattle Breeding Park.
"The primary goal of cloning excellent dairy cows is to concentrate the germplasm resources of dairy cows scattered in different regions of the country, with good adaptability, strong stress resistance, and super high yield, and preserve them in two forms of cells and living bodies." Xu Xiaotao told reporters.
The original individuals of this batch of cloned cows had more than 4 parities, an annual milk production of more than 18 tons, and a final milk production of more than 100 tons. Deputy director of the State Key Laboratory of Livestock Biology (Cultivation), Northwest A&F University Professor Jin Yaping described her as a "noble lady".
On December 30, 2022, the first excellent dairy cow of somatic cell cloning was born.
"Big body, born by cesarean section. Weight 56.7 kg, body height 76 cm, body oblique length 113 cm, body shape and color are exactly the same as somatic cell donor cows. Started to eat colostrum half an hour after birth, and is in good health." Productivity Promotion of Lingwu City Wu Dawei, director of the center, said.
Collect ear margin tissue and culture it into cloned embryos
The ingenuity of somatic cell cloning technology is that it only needs to collect the ear margin tissue of excellent dairy cows, bring them back to the laboratory to isolate and culture fibroblasts, and then use nuclear transfer technology to produce embryos to regenerate these individuals.
Jin Yaping believes that this approach not only avoids the possible biosecurity risks of introducing live cattle, but also greatly saves high-quality germplasm resources that are on the verge of being eliminated.
For the first batch of 120 cloned embryos transferred, the initial pregnancy rate reached 42%, and the pregnancy rate after 200 days reached 17.5%, which is at the international advanced level.
"These all indicate that the dairy cow somatic cell cloning technology has further matured in practical applications." He said.
"This is another major breakthrough between us and Northwest A&F University in the field of breeding technology for fine-bred dairy cows following the successful application of OPU-IVP technology in October 2022." Lingwu Science and Technology Bureau Director Ma Yuanfu said.
In recent years, Lingwu City has focused on the goal of building a "hometown of high-end milk". Under the guidance and support of the Ningxia Science and Technology Department, it has implemented a seed project to tackle key problems, and has carried out in-depth research and development of dairy cows' rapid breeding technology with Northwest Agriculture and Forestry University.
This year, Lingwu City plans to transfer 1,000 embryonic cattle and 500 births, transplant 300 cloned cattle and 30 births, use cloned cattle to produce 100 in vitro sex-controlled embryos, and realize mass breeding of embryos, especially high-yielding cloned cattle.
Fast multiplication of fine-bred dairy cows is a small step
As one of the top ten major dairy producing provinces in the country, this is also the first time that Ningxia has bred cloned cows.
In August 2022, the Ningxia Science and Technology Department launched the first batch of 4 "revealing the list and leading" projects, and implemented the "High-quality and high-yield dairy cow OPU-IVP industrial production technology research integration and industrialization demonstration" project.
Through the scientific and technological cooperation mechanism between the east and the west, Ningxia has integrated Shandong Oaks Animal Husbandry and Seed Industry Co., Ltd., Northwest Agriculture and Forestry University, Ningxia University and other units, and strives to build an innovation highland for rapid breeding of improved varieties, providing high-quality dairy cows for Ningxia and the whole country.
"At present, the project has integrated the application of technologies such as somatic cell cloning and live egg collection-embryo in vitro production-embryo transplantation, and established 4 in vitro embryo production centers, and established high-quality germplasm resources including open core groups of dairy cows and core groups of young cows There are 300 heads in each group, and 2,991 high-quality in vitro embryos are produced by young cow genome selection + live egg collection-embryo in vitro production technology, and 10 high-quality reserve bulls are cultivated.” Director of the Key Laboratory of Ruminant Molecular Cell Breeding in Ningxia Hui Autonomous Region, Ningxia University professor Ma Yun introduced.
A long journey, but one small step.
According to the project plan of the Department of Science and Technology, the overall process is divided into three steps.
The first is to improve the OPU-IVP technology system and promote the factory production of test-tube dairy cows; the second is to use somatic cell cloning technology to further select super-high-yield top cows; finally, based on this, combine stem cell technology with genome detection technology to implement laboratory breeding.
"This is a new track we have opened up." Xu Xiaotao said.