BCRC 3 - Quantifying tenderness polymorphisms and discovery of associated biological path

Summary

This research aimed to assess effects of calpain system polymorphisms for tenderness in Brahman cattle and their interactions with hormonal growth promotant, gender, method of hand and aging period. The improvement in longissimus shear force in normally (achilles) hung carcasses after 7 days aging was 1.20 kg for the NSW herd and 0.93 kg for the WA herd for the cattle with the favourable calpastatin/calpain 3 alleles compared to those with the unfavourable alleles (i.e. 0*0* vs. 2*2*). Significant improvements were also evident in the tender-stretched sides due to the favourable gene markers. Calpain-calpastatin system protein abundance and activity and gene expression results are consistent with the phenotypic findings in relation to shear force, and are helping to elucidate mechanisms responsible for the phenotypic effects. There were no significant adverse effects of the favourable calpastatin-calpain 3 alleles on growth during backgrounding and feedlotting, feed intake, feed efficiency, behaviour, stress responsiveness, or commercial carcass and MSA chiller assessment traits. An MLA Donor Company is being established to have samples we collected for MSA eating quality assessment eaten, to allow incorporation of the effects of the gene markers into the MSA model as an integral component of the path to adoption. The extent to which the tenderness gene markers are incorporated into breeding programs and for fine-tuning of processing to improve product quality and efficiencies will largely depend on successful outcomes of the MLA Donor Company. It is recommended that further research to elucidate the mechanisms by which the favourable alleles in the calpain system, and other factors, enhance tenderness be undertaken using data and samples obtained within this experiment.