Changing protein levels throughout growth

[pigpeople]

I am trying to figure out something. There are breeders (successful breeders) that feed with a technique of what amounts to changing to protein level of the feed almost every 1-2 weeks. They feed Moormans. Usually all high fat. I *think* the reason is as the pig changes on the higher protein (more muscle development - perhaps they get stiffer movement) they then lower the protein to soften them up and loosen them up...?
Or, is it a new fancy growing strategy that "pulses" protein? Maybe this either moderates growth rate (can prevent joint issues?)... I could think of a few more reasons but just wondering if anyone with more years of knowledge can figure this one out.
Let's brainstorm! Thanks!

[kgb]

It's really not protein that you should be concerned with, but Lysine. And energy (calories). Lowering protein by itself doesn't soften pigs. Lowering protein % in the feed, means lowering the protein ingredients (like soybean meal). And, when this happens something needs to take it's place (usually corn). So, as the protein comes down, the energy goes up. And again it's not protein that makes the difference it's lysine and other essential amino acids.

To explain, protein is composed of two kinds of amino acids; indispensable and dispensable (also called essential and nonessential). The difference is this; the pig either cannot synthesize indispensable amino acids or cannot synthesize them in sufficient quantities to meet the pig's daily requirement for them. So, for indispensable and or essential amino acids we must provide them in the diet everyday.

The problem is that with various types of feedstuffs used in feeds, we don't know how much of that protein is indispensable and how much is dispensable. So, the best next measure (actually a MUCH better measure) of indispensable amino acids is Lysine.

Another way to more accurately add energy (calories) AND lower protein if you want to look at it like that is to add fat to the diet. Here's an example (and forgive me for using Purina products, but I am very familiar with those):

Say, we are feeding 709 with is an 18% crude protein feed (1.1% lysine) and 6.5% crude fat. High Octane Heavy Weight contains 8% protein and 70% fat. So we are feeding 6 lbs per day 709. This results in the pig getting 18% protein and 6.5% fat. If we substitute 1 lb Heavy Weight for 1 lb 709 we get:

5 lb/day 709 which = 15% protein (5 lb 709/6 lb total) X 18% protein = 15%
1 lb/day Heavy Weight = 1.33% protein (1 lb HW/6 lb total) X 8% protein = 1.33%
Total crude protein = 16.33% (lowered from 18%)

Also:
5 lb/day 709 = 5.42% fat (5 lb/6 lb) X 6.5% fat = 5.42%
1 lb/day Heavy Weight = 11.67% fat (5 lb/1 lb) X 70% fat = 11.67%
Total crude fat = 17.09% fat (which is a HUGE jump from 6.5% by the way, and why if you don't start slowly at 4 oz per day, and increase at about 4 oz per day every 3-4 days, you knock pigs off feed).

Anyway, sorry for the length. But, the lysine content would be:

5 lb/day 709 = 24.95 grams lysine
1 lbday HW = 2.3
= 27.25 grams/day lysine

From 6 lbs 709 = 29.94 grams/day lysine

[pigpeople]

Thanks KGB! Those calculations make sense and are very helpful. But why would a breeder constantly be changing the protein % in a line of feed? Just using the protein as the base for changing the % lysine as in energy? Does this keep them fresher looking? Affect growth?

[dolfan31]

Doesn’t make a lot of sense to me. No breeders that I know feed that way.

[LzDy]

Perhaps they are changing the type of protein. All starter feeds are higher in protein but they also use animal based proteins instead of plant based protein. ie milk, fish meal, etc vs soy bean. KGB when is it that piglets can digest the soy if I recall it is about 6 to 7 weeks of age. They protein levels decrease down with time. What starter feeds does Purina have for creep and that starter KGB?

[kgb]

That is a good point; what do the pigs weigh or how old are they when breeders are doing this.

If it is at weaning when the pigs are 12-15 lbs and 3 weeks old or so, yes that make sense. But, it's not lowering protein. It is simplifying the diet. Newly weaned pigs' digestive tracts are very immature at that point and as the last poster pointed out they have a problem with soybean meal.

Usually, breeders will feed a very complex diet for the first week, and then transition to a less complex diet, and again 2 weeks later or so to an even less complex diet. This matches up with the pig's nutrient requirements, and it reduces the dietary cost (getting to a simpler diet as the pig's digestive system allows). It is nutritional and economical.

HONOR Show Chow has PRELUDE 209 as a Phase 1 prestarter (pigs weighing 12 to 15 lbs), and PRELUDE 309 for pigs weighing 15 to 25 lbs.
Then Showpig 509 for pigs 25 lbs and up.

[LzDy]

KGB going to send you a PM regarding feeds. Thanks