```json
{
  "sym_variables": [
    ("x1", "servings of elk meat"),
    ("x2", "servings of bison meat")
  ],
  "objective_function": "6*x1 + 7*x2",
  "constraints": [
    "5*x1 + 4*x2 >= 30",
    "3*x1 + 4*x2 >= 40",
    "x1 >= 0",
    "x2 >= 0"
  ]
}
```

```python
import gurobipy as gp
from gurobipy import GRB

# Create a new model
m = gp.Model("Minimize Cost")

# Create variables
elk = m.addVar(lb=0, vtype=GRB.CONTINUOUS, name="elk") # Servings of elk meat
bison = m.addVar(lb=0, vtype=GRB.CONTINUOUS, name="bison") # Servings of bison meat


# Set objective function: Minimize cost
m.setObjective(6 * elk + 7 * bison, GRB.MINIMIZE)

# Add constraints
m.addConstr(5 * elk + 4 * bison >= 30, "IronRequirement") # Iron constraint
m.addConstr(3 * elk + 4 * bison >= 40, "ZincRequirement") # Zinc constraint


# Optimize model
m.optimize()

# Check for infeasibility
if m.status == GRB.INFEASIBLE:
    print("The model is infeasible.")
else:
    # Print optimal solution
    print(f"Optimal Cost: ${m.objVal}")
    print(f"Servings of Elk Meat: {elk.x}")
    print(f"Servings of Bison Meat: {bison.x}")

```
