Interesting trade but why did you choose 4-2-8 and 5-3-10? Generally it is 4-3-8 and 5-4-10...
Yes the 4-3-8 and 5-4-10 ratios have been generally accepted. Past posts of mine have used these ratios. However I fallow the Cattle Finishing business very close. I have data going back to 1975 and have compiled data from USDA placement and slaughter reports. I also continue to do personal research by visiting numerous feedlots and cattle auctions each year.
In the 1950s the Feed Conversion Ratio (FCR) was 10:1 through extensive dietary research, genetics via selective breeding, and other factors, the FCR is today pegged @ 6:1
The U.S. Department of Agriculture, National Agriculture Statistic Service provides monthly feedlot placement reports with breakdowns for < 600 lbs., 600-699 lbs., 700-799 lbs. > 800 lbs., based on these reports the average placement weight is 708 lbs. Reports for Federally Inspected Beef Slaughter Live weight show an average of 1235 lbs. . Therefore the average of 750 lbs. feeder input vs. 1250 lbs. Live output with a 500 lbs. weight gain is still used.
1 Feeder Cattle contract = 50,000 lbs. or ~ 66 head. ( 50,000 / 750 )
1 Live Cattle contract = 40,000 lbs. or ~ 32 head. ( 40,000 / 1250 ) x 2 = ~ 64 head.
For our analysis of each ratio, we'll round it to 65 head per spread and take the number of head X the 500 lbs. to calculate total Pen Weight Gain (PWG). Example: 2 Live = 65 hd. X 500 lbs = 32,500 PWG.
The 4-2-8 ratio = ~ 260 head x 500 lbs. = 130,000 lbs PWG
70% of 130,000 lbs. = 91,000 lbs. x FCR @ 6 = 546,000 lbs. of Corn / 56 lbs. per bu. = 9,750 bu.
75% of 130,000 lbs. = 97,500 lbs. x FCR @ 6 = 585,000 lbs. of Corn / 56 lbs. per bu. = 10,446 bu.
So based on research IMO the ratios of 4-2-8 or 5-3-10 more accurately reflect and mimic the cattle finishing business of today.
It should also be stated that provided the GFM increases as anticipated the 4-3-8 should also perform well.
Since it was my intent to follow-up on this strategy It will be no trouble to include a comparison with other ratios. Should be interesting.
I well post the details for the other ratios with the same prices shortly