WELCOME to the Forum!!
I am not familiar with the foods you are offering.
The basics of putting weight on any horse is to offer more calories than the horse consumes in work, play or whatever.
To lose, reduce the calories the horse uses so they burn excess fat losing weight...
So, I would not
put a horse, any horse intentionally to a body score of a 6.
5 is optimum, 6 is headed toward, actually somewhat already obese.
With the exception of broodmares pregnant or a servicing stallion... no, just no.
Thoroughbreds are not
encouraged to be "fleshy" in appearance.
You are referring to putting several hundred extra pounds on a horses frame, taxing his heart, lungs and organs along with legs, support structures and their hooves...
A horse who looks healthy, absolutely.
A horse who has a crease down its back, spongy ribs not felt and a fat spongy tailhead...no to me that is to much weight and unhealthy for the horse..
Far healthier to have a horse who is fleshed, with lightly covered ribs that you should see when they are moving/running ripple under the coat, flanks that are flat when you look from tail forward, points of a shoulder covered & softly rounded, a neck that blends softly into the wither, but the juncture of neck, shoulder and spine are not bulging with fat deposits which is detrimental to good saddle fit, or a tail-head that looks covered with cellulite and when you touch it your finger sinks in nor a channel with bulbous fat like a river channel down the spine..
To reach your description desires, that is how your horse would look to me...
Equate this with going to the beach and watching those parading past you in bathing suits.
What looks better on either sex...to see soft lines with muscle rippling under the skin or fat protruding and wiggling every step taken...
A horse, a Thoroughbred is actually supposed to be between a 4.5 - 5 scoring. True.
Today, so many see fat animals as the norm, it has become the norm but it is not
healthy for the animal.
Take 50 pounds and you carry it around all day long for the next 2 days and see if you honestly want to gain that extra weight you carried and could put down...now think about that in relation to your horse, the size and ratio of excessive weight you refer to and his body deals with.
There is a happy medium here I think you should look to for the horses sake.
Sure a true 4 on the scale is thinner than you want...but to add 300 - 400 extra pounds is a huge upswing on the animal.
From a 4 to a 5, a solid 5
is about 200 pounds...more added than that to go to a 6...no.
Sorry, as soon as the words creases and spongy are in the body scoring description you went from slightly under to tip the scale on the way to obese.
To me, there is a huge difference going from a 5 to a 6... 5: Moderate Neck blends smoothly into body. Withers rounded over spinous processes. Back level. Fat around tailhead beginning to feel spongy. Ribs cannot be visually distinguished but can be easily felt. Shoulder blends smoothly into body.
6: Moderately Fleshy Fat beginning to be deposited. Fat beginning to be deposited. May have slight positive crease down back. Fat around tailhead feels soft. Fat over ribs feels spongy. Fat beginning to be deposited.
I would far rather my horse be a solid 5 on the scale than a 6 and the health concerns extra stress on the body bring hardship and problems your way with greater potential.
I can only say a Thoroughbred is not
supposed to resemble a stock horse in being round and pudgy appearing, but is supposed to be lanky, leaner and sculpted long muscle not heavy mass.
What you decide to do to your horse weight wise is something only you will know...I err on well covered, healthy looking but not obese which a Thoroughbred reaching a score of 6 is...
Think carefully and be the advocate for your horse to have lasting good health and less chance of health concerns being obese, even "slightly" brings.
Below are 2 different places and articles on scoring, why you want to be in a certain range for the horses benefit. http://images.equinetwork.com/EQUUS/...hsfp=165344926