Preview: Improved mitochondrial efficiency in Bos indicus cattle: a new mechanism for thermotolerance?
Credit: Journal of Animal Science, Volume 98, Issue 3, March 2020, skaa074, doi.org/10.1093/jas/skaa074
Publisher: American Society of Animal Science
Rights: Name must appear as a credit whenever the image is used- Journal of Animal Science, Volume 98, Issue 3, March 2020, skaa074, https://doi.org/10.1093/jas/skaa074
Description: Thermotolerance is an important factor to consider when rearing livestock in the face of climate change and environmental uncertainty. In subtropical areas within the US, a large percentage of cattle are Bos indicus-influenced owing to their parasite resistance and suitability to hot, humid conditions (for review see Cooke et al., 2020a,b). Their improved survivability and efficient use of the poor quality forages found throughout these regions is offset by reduced carcass merit and meat quality.
Meat quality is affected by the rate of postmortem metabolism and pH decline in muscle. Brahman cattle demonstrate greater amounts of muscle ATP than Angus during the initial postmortem period with no differences in citrate synthase activity suggesting that the mitochondria are more efficient in Brahman (Ramos 2020a). A recent paper by Ramos in this issue reports that mitochondria oxygen consumption rates are greater in muscle isolates from Brahman cattle by comparison to Angus supporting the hypothesis of improved ATP synthesis by the mitochondria. By extrapolation, the authors suggest that improved mitochondria efficiency can lead to less heat production. These efforts provide novel insight into muscle adaptations that may underlie thermotolerance.