Smaller cows cost less to keep and reduce emissions

It is a subject all producers will have to address as Farming for Net Zero approaches and the ability to make ends meet becomes more of a challenge with soaring costs of production.

Genetics can however make a huge difference to margins and are already playing an increasingly important role in reducing greenhouse gas emissions. According to Marco Winters, head of animal genetics at AHDB, emissions can be reduced >1% per year through genetics, which by 2040 would result a 20% drop.

Marco Winters AHDB

Speaking at the online British Cattle Breeders' Conference, he told delegates, breeding smaller, more efficient cows for the environment, not only produce less emissions but also cost less to keep.

"On average dairy cows are 30kg heavier now than they were in the 1990s which in turn means they require an extra 60,000tonne of feed per liveweight kg per day purely for maintenance.

"If you have got a 200-cow herd, that is an extra 10 cows/passengers that need fed each day for no other reason than maintenance and these animals are a huge cost to the environment in the amount of extra methane they produce.

"Maintenance is a hidden cost, and bigger animals are still selected over smaller ones, even though larger animals cost more to feed. If you can reduce your maintenance costs you will reduce the environmental cost and financial cost to your business."

In trials he said, two animals can produce the same amount of milk on the same farm and in the same lactation with the only difference being one is a 100kg heavier than the other. However, the heavier cow will always costs more to feed and in trials this amounted to £500 – a price that will be a lot more now given the increase in feed prices.

Outwith cow size, Mr Winters said breeding healthier animals in high welfare units will improve herd longevity which in turn also reduces emissions as overall herd efficiency and profit margins improve.

Producers can also breed for efficiency and to reduce emissions, by selecting sires for the two new genetic indexes – EnviroCow and Feed Advantage.

Dairy genetics

Incorporating cow lifespan, milk production, fertility and the new Feed Advantage index, EnviroCow is one of the first genetic indexes in the world to focus solely on breeding cows for their environmental credentials.

EnviroCow reflects the important role genetics and breeding play in improving the environmental efficiency of milk production. This index is expressed on a scale of about -3 to +3, where the highest positive figures are achieved by bulls which transmit the best environmental credentials to their daughters. These will be cows which are predicted to create the least GHG emissions in their lifetimes for each kilogramme of solids-corrected milk they produce.

Feed Advantage, incorporated in EnviroCow, helps dairy producers identify bulls with the greatest tendency to transmit good feed conversion on to their daughters. It is expressed as a Predicted Transmitting Ability (PTA) in kilogrammes of dry matter intake saved during each lactation.

The index’s launch represents the culmination of more than 30 years of research and data collection from the award-winning Langhill herd in Dumfries. Undertaken by Scotland’s Rural College (SRUC), the studies have measured the Langhill cows’ dry matter intake throughout their entire lives.

“Calculations take account of the feed an animal is expected to eat given her solids-corrected milk production and the feed she needs for her maintenance,” says Mr Winters.

“This is compared with her actual feed consumption to identify animals which are efficient converters.”

Adjustments are made for the size of the animal, as a smaller cow requires less feed than a larger cow giving the same level of milk production.

The most efficient cows consume as much as 400kg less in one lactation compared with the least efficient cows, meaning that for the same level of production there is substantial scope for cutting feed use.

“EnviroCow and Feed Advantage will help farmers have a positive impact on the use of the world’s finite resources and the carbon footprint of UK dairy farming. Now they can move this up a gear with genetic indexes designed specifically to improve their dairy cow’s carbon emission credentials.”

Mr Winters added that producers can also breed for efficiency by selecting sires with high profitable lifetime indecies (£PLI), which naturally tend to be good for the environment.