The microbiome, by definition, is all microorganisms in an environment, which include bacteria, protozoa, viruses, fungi, nematodes, and archaea. The rumen microbial composition is impacted by both diet and the animal’s genetics, and the microbiome is essential for breaking down indigestible plant material.
The intersection of heritability and phenotypic variance of microbiome and the effect on traits like feed efficiency and methane (CH4) production is where this research becomes very interesting and complex. Researchers at Scotland’s Rural College (SRUC) have been investigating the approach where microbiome-focused breeding could soon be a cost-effective selection criterion and strategy for reducing CH4 emissions.
In their research, conducted on beef breeds Angus, Limousin, Charolais crosses, and Luing, CH4 emissions were individually measured in respiration chambers for a portion of the animals in the study, in addition to collection of blood and ruminal fluid samples. The team identified 43 informative microbial genes, 17 of which were positively genetically correlated with CH4. The remaining 26 were negatively correlated.
Ultimately, the team looked at multiple trait models for selection criteria, which included production traits like daily feed intake, average daily gain, and cold carcass weight, concluding microbiome-driven breeding for reduced CH4 was successfully integrated.
In addition to beef research, studies on the direct genetic effects of the genome and microbiome and feed efficiency in dairy cattle have been evaluated in recently published papers, helping to explain why cows at similar body weights need less feed to produce the same amount of milk.
This complex research, along with many other similar studies, opens up the door for helping us understand both functional and genetic pathways, and the continued junction of genetics and microbiome is contributing to improved sustainability, generation over generation.
