Step 1: Count cows by color in the sketch.
- White cows = 7
- Brown cows = 6
- Yellow cows = 7
Step 2: Contribution by type.
- White cows: $7 \times 12 = 84$ L
- Brown cows: $6 \times 7 = 42$ L
- Yellow cows: $7 \times 10 = 70$ L
Step 3: Total milk per day.
\[
84 + 42 + 70 = 196 \, \text{litres}
\]
Final Answer:
\[
\boxed{196 \, \text{litres/day}}
\]