I am going to reapply UK Standard Visitor Visa. What should I add in employer's letter that can be acceptable to ECO?
In short, your financials don't seem to make sense.
Your application says you earn PKR 78,000/month working for Punjab Beverage Company. Therefore, the ECO expects to see the same salary stated on the letter from your employer and he expects to see the same amount of money deposited into your bank account every month. Why is this not happening? If your income is actually irregular from "agricultural and cattle farming," why does your application say you earn this salary from Punjab Beverage Company? And if you do receive that salary from the Beverage Company, where is it going if not your bank account?
We have an answer here Should I submit bank statements when applying for a UK Visa? What do they say about me?, which will tell you more about bank statements and what the ECO is looking to see from them.
Also, the ECO doesn't understand why your employer is promising to pay for the cost of your vacation. Normally, your employer would only pay for your trip if it was for business purposes.
Most importantly though, is the first paragraph. You applied previously, and the ECO found that "there is no evidence to show there has been any significant change in your circumstances since then." For a new application to be successful, you would need to show significantly different personal circumstances, such as greater ties to your home country. I would not apply again unless and until you are able to do so.