To calculate the average weight gain of the beef cow, we first need to determine the total time in days.

 Determine the Total Time in Days.

Two months: Assuming an average month has about 30 days:
 \(2 \text{ months} = 2 \times 30 = 60 \text{ days}\)

Two additional days
 \(\text{Total time} = 60 + 2 = 62 \text{ days}\)

The average weight gain per day is calculated as follows:
\(\text{Average Weight Gain}\) = \(\frac{\text{Total Weight Gain}}{\text{Total Time in Days}}\) = \(\frac{75 \text{ kg}}{62 \text{ days}}\) \(\approx 1.21\text{ kg/days}\)

Thus, the average weight gain is approximately \( \mathbf{1.21} \text{ kg/day}\).