Scientists have been studying Chinese pigs since the late 1980s in their efforts to increase the number of offspring produced by U.S. pigs.
In the process, United States Department of Agriculture researchers have found many interesting reproductive facts about the Meishan (pronounced MAY-shawn) pigs of southern China.
Meishan males have five to seven times more follicle stimulating hormone in their blood than U.S. boars. FSH aids in the production of sperm.
Meishan males’ testes were 40 percent smaller than those of U.S. boars.
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The researchers found that while a gene or genes on the X chromosome affects the size of the Meishan male’s testes, testes size in other species, such as rodents, is more affected by genes on the Y chromosome.
Scientists were also attracted to the Meishans because they provide a good model for investigating sperm production.
Animal physiologist Joe Ford said 75 percent of newborn pigs in the U.S. are produced through artificial insemination, so improving sperm production helps improve pork production efficiency.
Ford’s laboratory is using Meishans only as an experimental model to compare to other breeds. He said meat production is not as desirable as other pigs because Meishan pork contains more fat.
Other USDA researchers are studying female Meishans and their large litter size.
They’ve found that the females begin puberty in 60 days, compared to 150 days in other pigs.
The females ovulate more eggs per cycle than American pigs. They also have a greater uterine capacity, meaning they can deliver more live piglets.
