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Innate immunity genes linked to higher milk yield

High yielding milk cows have been associated with reduced innate immunity leading to mastitis, endometriosis and reduced fertility. An EU-funded project has identified key immunity genes that could be incorporated into breeding programmes.
Innate immunity genes linked to higher milk yield
A multi-pronged approach is needed to identify genetic mechanisms behind quantitative trait loci (QTL) in cattle. In turn, characterising single nucleotide polymorphisms (SNPs) in genes that confer an efficient immune system and mastitis resistance could result in higher quality milk and less reliance on antibiotics.

The INNATELYBETTERCOWS (A genomics approach to increasing disease resistance in dairy cows through improvements in innate immunity) project studied disease trait genes in Chinese dairy cows using association studies. Researchers also studied peripheral blood cell responses to bacterial pathogens in cows with different genotypes for innate immune responses.

Research results showed that differences in genes regulating innate immune response play an important role in susceptibility to mastitis and influence milk production in Holstein cattle.

Two genes showed significance – Triggering receptor expressed on myeloid cells 1(TREM1) and Mitogen-Activated Protein Kinase Kinase Kinase Kinase 4 (MAP4K4). Both play important roles in inflammation and differences in protein structure between cow and buffalo MAP4K4 genes could change inflammatory responses.

In vitro, the TREM1 gene showed potential for immune function improvement. Increasing pro-inflammatory cytokines in vitro was inhibited by down-regulation of TREM1 messenger RNA.

Another two genes with possible effects on immunity were TLR2 and INOS. Sequencing in 450 Holstein Friesian and 115 Brown Swiss cattle showed eight SNP with low to moderate effects on the gene product in INOS and four with a moderate effect in TLR2. Research is still in progress to see if these genes are responsible for differences in protein production and the superior resistance to mastitis seen in Brown Swiss herds.

INNATELYBETTERCOWS research results show it is feasible to increase disease resistance by selectively breeding cows using marker assisted selection to improve their innate immune response. Breeding healthier cattle will not only reduce antibiotic usage but could lower the minimum number of cattle needed for milk production, curbing the impact of dairy farming on the environment.

Related information

Keywords

Innate immunity, gene, milk yield, mastitis, SNPs, INNATELYBETTERCOWS
Record Number: 198603 / Last updated on: 2017-05-26
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