I'm looking for studies that include feed to food conversion factors for pasture land. I mean the total livestock feed calories used divided by the human-consumed calories they yield. I have found Eshel et al. (2014) study (see attachment), but this study only consider pastures as feed for beef and no other production systems e.g., dairy and within the USA. Might you know about other potential studies that include the feed to food conversion factors for pasture land? And might you also know conversion factors for countries such as Ecuador, Peru, Bolivia, Colombia? Thanks.
You might find the study by Cassidy et al. (2013) useful. The other study by Pradhan et al. (2013) also provide the feed calorie embedded in animal products. It follows a very simplistic approach and seems they have not accounted for the grazing.
You might find this paper useful: Hurley et al., Inter-relationships among alternative definitions of feed efficiency in grazing lactating dairy cows
Hi Gloria,
Publications reporting ‘feed-to-food conversion factor’ for purely pasture based ruminant systems are rare, as the majority have focused the discussion on livestock systems relying on ingredients that can be directly used for human nutrition. Under the latter scenario, ruminants are at an extremely unfavorable position. However, in systems where ruminants are fed from grasslands and by-products of food production (by-products that humans cannot consume), ruminants can be seen differently (Schader et al. 2016, below). In fact, when ruminants are raised on judiciously managed pasture systems, they may even contribute positively to reduce the agriculture’s carbon footprint while also contributing to food security (as explained by Teague et al. 2016). The third paper below also discusses the same issue, but using a different indicator (land use ratio or land use efficiency).
Schader et al (2016) Impacts of feeding less food-competing feedstuffs to livestock on global food system sustainability. http://rsif.royalsocietypublishing.org/
Teague et al (2016) The role of ruminants in reducing agriculture’s carbon footprint in North America. Journal of Soil and Water Conservation. VOL. 71, NO. 2. 156-164. http://www.jswconline.org/content/71/2/156.abstract
Van Zanten et al. 2016. Global food supply: land use efficiency of livestock systems. Int. J. Life Cycle. Assess. (2016) 21:747–758. http://link.springer.com/article/10.1007/s11367-015-0944-1
Hi there!
I've found a few that might help you. In order to get the calories consumed by humans, you could multiply the litters of milk produced by the approximate calories of regular milk (yes, it is an estimate, but it might suit your purpose). You could do the same for meat, estimating calories provided by a kg of meat.
Mackle, T. R., Parr, C. R., Stakelum, G. K., Bryant, A. M., & Macmillan, K. L. (1996). Feed conversion efficiency, daily pasture intake, and milk production of primiparous Friesian and Jersey cows calved at two different liveweights. New Zealand Journal of Agricultural Research, 39(3), 357-370.
Arthur, P. F., Archer, J. A., & Herd, R. M. (2004). Feed intake and efficiency in beef cattle: overview of recent Australian research and challenges for the future. Animal Production Science, 44(5), 361-369.
Hope it helps. A lot of research on pasture-based systems has been conducted in NZ and Australia. You might want to start from there. Good luck!
Gloria, I don't know the intended use of the info you are seeking, but for sure you start with a wrong study. Grazing lands devoted to grazing, are not suitable for a regular cultivation. Even in rich soils were best use is cultivations, if there is any grazing, is on leftovers or by products. The study fails to calculate the enrichment of soil by the livestock. That "energy" put in the soil doesn't count? It should be added back to the calorie calculation. And a question to you, left over straw or anything else, what does it give us every time when breaks down? either CO2 or CH4 or both. If is self emitting or via the animals, does it make any difference? If you want an accurate result, design your own test on identical land though, otherwise you results will be distorted and unrealistic or fake. Do not follow that school of wrong thinking.
Best of luck.
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