Esshup, the conversion of 6 to 1 is a decent estimate for all LMB in north Texas so long as one understands the conversion is for the excess over maintenance. In the example above the pond provides the maintenance. They won't grow without an excess of consumption above maintenance. Without the supplement the consumption is 6 times the weight of the LMB and the gain is zero. Because the gain is zero the FCR is infinite and is in fact meaningless. With consumption above maintenance, there can be conversion and a finite FCR.
Gains can be negative. Just take away some of their maintenance. They will decline to match what the consumption can maintain. Examples of taking away some maintenance? Stop fertilizing, stop feeding, use pond dye, fail to maintain alkalinity are a few examples. Even an exceptionally cloudy summer can adversely affect the production of food.
