Genomics to benefit livestock production: improving animal health

ABSTRACT The primary principle underlying the application of genomics is that it has the most value for difficult and expensive to measure traits. These traits will differ between species and probably also between markets. Maintenance of health will be one of the biggest challenges for efficient livestock production in the next few decades. This challenge will only increase in the face of demand for animal protein, resistance to existing drugs, and the pressure to reduce the use of antibiotics in agriculture. There is probably genetic variation in susceptibility for all diseases but little has been done to make use of this variation to date. In part this is because it is very difficult as well as expensive to measure this variation. This suggests that genomics should provide one of the ways of tackling the challenge of improving animal health. This paper will discuss the concepts of resistance, variation in susceptibility, and resilience; provide examples and present some recent results in cattle and pigs; and briefly discuss the application of gene editing in relation to disease resistance

Investigation of the tonB gene product of Escherichia coli.

The active transport of all ferric chelates and vitamin B12, infection by bacteriophages T1 and ?80, and killing by a group of colicins are dependent upon the tonB gene product. The initial stage in these processes is an energy-independent binding of the 'substrate' to specific receptor proteins in the outer membrane. Subsequent stages of transport require an energized inner membrane and the tonB gene product. The aim of this study was to identify the tonB product in order to investigate some of its properties directly. The use of ?-tonB transducing phages carrying wild type and mutant tonB alleles to program protein synthesis in UV-irradiated cells enabled the tonB product to be identified; a 40 kilodalton protein was no longer synthesised from tonB deletion and insertion mutants. This protein was associated with the sarkosyl soluble, inner membrane fraction of irradiated cells, suggesting that the translocation of ferric chelates etc. from their initial binding sites, at the exterior of the cells, is dependent upon an inner membrane protein. In an attempt to identify the tonB protein in vivo the tonB region was recloned into a runaway replication plasmid vector. Although cloned proteins were identified, the tonB product was not detected using this system. Physical maps were prepared for the phages and plasmids used in this study, and compared with those described by other workers. The approximate position of the tonB gene was also located. The gene products coded by the tonB region were also identified by utilizing an in vitro coupled transcription translation system. Interestingly, the mutant tonB genes programmed the synthesis of truncated polypeptides in this system. Finally, these results and those of other workers are drawn together to present some models for the action of the tonB product

Use of genomic tools to improve cattle health in the context of infectious diseases

Although infectious diseases impose a heavy economic burden on the cattle industry, the etiology of many disorders that affect livestock is not fully elucidated, and effective countermeasures are often lacking. The main tools available until now have been vaccines, antibiotics and antiparasitic drugs. Although these have been very successful in some cases, the appearance of parasite and microbial resistance to these treatments is a cause of concern. This review describes the rapid gains achieved to track disease progression, identify the pathogens involved, and map pathogen interactions with the host. Next-generation sequencing provides important opportunities to tackle problems associated with pathogenic illnesses. Use of novel genomic tools subsequently aids in treatment development, as well as successful creation of breeding programs aimed towards less susceptible livestock. These may be important tools for mitigating the long term effects of combating infection and helping reduce the reliance on antibiotic treatment