Why is this important? 

Cattle naturally produce methane as part of digestive processes. However, methane production varies between cattle fed the same feed and producing the same amount of milk. Genomic analysis can be used to predict which animals are likely to be more methane- efficient than others. The main aim of this project is to see how much we can reduce methane production per kg milk through selective breeding. A secondary aim is to select animals with increased efficiency and health (Envirocow and PLIs). All animals will naturally produce emissions over the course of their lifetime (namely methane, carbon dioxide and nitrous oxide). Animals with a longer lifespan, better health, better fertility and higher production (i.e. milk yield) will have lower emissions per kg of output (e.g. fat- and protein-corrected milk). Therefore, selecting animals with increased efficiency and health will improve productivity over their lifespan, meaning that their total emissions are diluted over a higher lifetime production.

Why are we focusing on methane? 

Although methane production is a perfectly natural process in ruminants, it is a greenhouse gas that is estimated to be 28 times more potent than carbon dioxide, meaning it is a significant contributor to global warming and climate change. However, methane has a much shorter half-life than carbon dioxide, thus it starts to break down in the atmosphere after roughly 11 years, unlike carbon dioxide, which sticks around for much longer - around 120 years. Therefore, if we can reduce the amount of methane being released into the atmosphere (by any means), we can very quickly achieve a positive cooling effect, which will buy time for other solutions to be developed and implemented that will combat the effects of excessive fossil fuel consumption.

Why have we chosen IVF?

Most cows can only have one calf per year which means genetic progress can be slow. In vitro production of embryos allows us to produce more calves from the best animals more quickly, so we can see two generations during the project.

Hilda's Journey so far! 

In January 2024, we identified heifers from the Langhill herd at SRUC which scored well for the following genetic indices:

 ● EnviroCow - a genetic index which focuses on breeding cows for environmental efficiency, namely cow lifespan, milk production, fertility and feed conversion ratios.

 ● PLIs (Profitable Lifetime Indexes) - which aims to improve dairy cow’s profitability, productivity and overall health

 ● Methane Efficiency - an estimate of the production of methane at the same level of milk, fat and protein yield; some cows naturally produce less methane than others and this has a genetic component to it.

After health-checks, several heifers were selected to undergo ovum pick-up and in vitro fertilisation (OPU-IVF) to produce the next generation of climate-friendly calves. 

These heifers were super-stimulated with follicle-stimulating hormone (FSH) to produce as many oocytes (eggs) as possible, which were then collected under epidural anaesthesia. The next day, oocytes were fertilised in the lab using semen from North American bulls which also scored exceptionally highly for PLI, Methane Efficiency and the Envirocow Index. After a seven-day incubation period in the lab, the embryos have developed enough to be implanted into surrogate mothers, which give birth naturally 9.5 months later. Hilda was the first of these very special calves! 

All calves produced through IVF in the Cool Cows project will be genomically tested after birth to see how they score for these environmentally-friendly traits. After weaning, they will have their methane measured out in the fields using the ‘GreenFeed’ technology to see if they actually produce less methane than the average cow from the same breed. If successful in these measurements, the calves will eventually go on to become donors themselves once they are old enough and will also undergo IVP to produce another cohort of animals with genetics that are focused on environmental traits.