Like a number of primary industry sectors, sheep farming is increasingly under scrutiny due to the greenhouse gas emissions of the animals.
In particular, sheep belch and fart methane gas, which is 80 times more potent than carbon dioxide at trapping heat in the atmosphere, and therefore contribute to global warming. Now, in a bid to bring down greenhouse emissions, British farmers are trying to breed low-methane emitting sheep via genetic engineering.
The approach builds on a successful trial in New Zealand whereby researchers selected and bred the world's first low methane-emitting sheep.
"This project is great because it demonstrates how livestock producers can be part of the solution to produce food sustainably rather than being the problem," said Rob Hodgkins to Euronews, a sheep breeder at Kapoi farm.
"It's not the whole answer, obviously, but if we can cut methane emissions by 15 percent without reducing productivity and do so relatively quickly and cheaply, it would go some way," he added.
How do you breed low methane-producing sheep?
According to a 10-year study by New Zealand experts, breeding low methane-producing sheep appears to be feasible.
The research project started by proving that some sheep had naturally reduced emissions and that this characteristic was handed down through generations. With this in mind, how do scientists establish how much methane a sheep is burping out, anyway?
To assess the methane emissions of animals, researchers have access to various instruments. These include "portable accumulation chambers," PACs, and respiration chambers. In respiration chambers, the air entering and leaving the chamber is continuously sampled by automated equipment. Airflow, humidity, and temperature are all constantly regulated too.
PACs tend to be the cheaper, more portable option, though. These are sheep-sized polycarbonate boxes that can be lowered over a sheep in a sheep shed. After holding the sheep inside the PAC for 50 minutes, air samples are collected and analyzed for methane levels.
Researchers separated the sheep into two closed flocks of high-emitting and low-emitting animals after measuring the methane emissions in an initial herd of 1,000 sheep. These flocks were utilized to demonstrate the heritability of certain features.
The team demonstrated that in year 1, methane reduction was 1 percent. Additionally, sheep produced 11 percent less methane emissions per kilogram of feed eaten after three generations.
The UK trial's flock is genetically related to sheep stock in New Zealand that was selectively bred for low emissions this year, indicating that it may well succeed.
