According to a recent study, The impact of crossbreeding and feed efficiency on methane emission led by SimHerd, crossbred cows can reduce methane gas emissions by up to six per cent compared to pure Holstein cows.
The study was conducted using the simulation model SimHerd, and is part of the DairyCross project founded by Green Innovation and Demonstration Foundation in Denmark, in which other key institutions are also participating.
SimHerd consultant Ruth Davis Kring said that in the simulation model they had plenty of different specifications to measure heterosis and breed differences.
“All those parameters were put into the model so that when we run it the model can predict what the effect would be in the herd going from a pure-breed Holstein to a crossbred herd with given breed combinations,” she said.
“Some of those effects may be related to methane emissions.”
She said the main driver of the decrease in methane was the reduction of youngstock.
“The primary reason is that crossbred cows live longer, so you don’t need as many replacement animals, resulting in a smaller youngstock herd.
“When you have fewer animals, you lower methane emissions at herd level.”
She said the reason why crossbred cows lived longer was that they were more robust, healthier, and were more fertile so there was no need to replace them as quickly as the pure Holstein cows.
A case herd was modelled in the study, with 200 purebred Holstein cows.
Different crossbreed strategies
The replacement rate for pure Holstein was 40.7 per cent; for the different crossbreeding strategies, this was reduced to -6.3 per cent for the two-way cross with RDM, -7.7 per cent for the breeds under the ProCROSS concept, and -7.8 per cent for the breeds marketed as VikingGoldenCross.
Ms Davis Kring said she was convinced of crossbreeding’s ability to reduce methane gas emissions at the farm level.
“It can be part of the solution to face climate change and global warming challenges,” she said.
The breeds in the study:
● Two-crosses between Holstein and VikingRed;
● The breeds under the ProCROSS system: Holstein x VikingRed x Montbeliarde; and
● The breeds known as VikingGoldenCross: (Holstein x VikingRed) x VikingJersey.