Protein versus Lysine

[Macs B]

What is the best ratio of lysine to protein in a show pig feed? I know the subtle changes in Lysine content in HSC feeds isn't accidental. With 18% protein lysine is 1.1% but with 30% protein the lysine is 2.8%. Obviously the formula is changing based on the protein content. Is there a basic formula for this? When you evaluate the level of lysine in 209 thru 909 the ratio doesn't strike me as being incremental. If I'm not asking for a trade secret I would love to know the logic that went into the various formulations and why the subtle changes.

[Mary-Okie]

KGB will most likely have a more specific answer than mine, but here is how I determine % Lysine. Lysine is the most limiting Amino Acid in swine. Meaning that when Lysine runs out, then the pig doesn't convert amino acids into weight gain and muscle, and the remaining amino acids just become urea and are removed from the bloodstream by the liver and then removed from the body by the kidneys.

By adding Lysine to a diet, you are better able to use higher % of plant based feeds such as corn, wheat, barley and other low protein feedstuffs in the diet and reduce the amount of Soybean meal.

You base the % of Lysine in the diet by the feed intake. Hence the higher % in baby pig feed versus a finishing feed. Typically, a 1.2% and higher Lysine for baby pig feeds, 1 - 1.2 % for grower feeds and then 0.9 - 1 % in finisher feeds.

Where you start to see adjustments in % Lysine in older showpig feeds is in the feeds used for limit feeding. Also, the protein supplements will have high % lysine as they are to be used to enhance muscle development and that can't be done without an ample amount of the most limiting Amino Acid.

So look at the recommended feed intake of a feed when also looking at it's nutrient value.

Personally, I think some show pig feeds have too much lysine in them for the size of the pig and intake level. In addition, I think there is an over use of protein supplements. This is one of the areas where feed costs can get out of control. Excess Amino acids are just excreted from the body. I can think of other ways to spend my money!

[kgb]

Lysine % in the feeds change to more accurately meet the pig's lysine requirement. In terms of grams per day, lysine increases as the the pig grows from 4-5 grams / day at 12 lb in bodyweight to 25 grams /day at over 200 lb.

However, when it is expressed as a % of diet it decreases because the pig is eating more and more as it gows.

For example a pig weighing 12 lb eats about 0.35 - 0.5 lb per day. A pig weighing 200 lb or more eats at least 6 lb per day (hand fed). The Honor Show Chow products are not "just" feeds with different protein and lysine levels. They are a complete feeding program from weaning to show.

Hope that helps.