"Considering Kerry and Limerick have over 200,000 cows between them, Carlow and Kildare's population of 30,000 cows looks to have huge room to increase," said Mr Kelly.
There were 190,640 more cows in Munster in 2016 compared with 2010; 101,550 more in Leinster, 15,705 more in Connacht and 19,229 more in the Ulster counties of Cavan, Monaghan and Donegal.
The surge in cow numbers reflects the profitability of dairying compared to other farming enterprises.
"The real story here is not just the increase in scale but the potential increase in profitability," said Mr Kelly.
The recent Teagasc National Farm Survey showed the average dairy farm earned €51,809 for 2016 - a year of poor milk prices - compared with €30,816 in tillage and €12,908 for suckler farms.
"Producing milk from grass in Ireland is profitable and it's great to see Irish farmers increasing scale in a profitable way.
"Debt per dairy farm has only increased slightly during this expansion and cost of production has held steady," added Mr Kelly.
Among the traditional dairy counties, Tipperary, Waterford and Kilkenny all had growth rates well above the national average of 31pc. Cork and Limerick increased at a rate below the national average.
However, the 77,000 increase in Cork to a total cow population of over 362,000 means Cork has more cows than 20 other counties combined.
Kerry was one of the slower growing counties nationally with a 21pc increase in cow numbers.
Overall, the national herd increased by 31pc between 2010 and 2016 to 1.35 million cows.
Leinster experienced the largest rise at 36pc, compared with 29pc in Munster and Connacht.
However, Munster recorded the greatest number of extra cows milked.
The top five counties in terms of cows and percentage of the national herd in 2016 are:
- Cork - 362,898 (26pc)
- Tipperary - 159,207 (11pc)
- Limerick - 115,558 (8pc)
- Kerry - 103,255 (7pc)
- Kilkenny - 81,076 (6pc)
These five counties account for 59pc of the national herd.
There was more regional variation when it came to counties recording the biggest expansion in cow numbers.
The number of dairy cows in Westmeath surged by 43pc to 25,701 cows from 2010 to 2016.
Offaly and Galway rose 41pc to 27,820 and 34,905 respectively, while Kilkenny and Waterford rose 40pc to 81,076 and 77,841 respectively.
The number of cows in Roscommon rose from 4,875 to 6,532 - a 34pc rise since 2010.
"Roscommon has seen a few big new farms set up in recent years and could continue to grow strongly as has Westmeath. While recent high profile tillage converts in Wexford might spur on confidence in dairying in that county," said Mr Kelly.
Teagasc say that unlike other countries, Irish farmers do not have to be massive operators to make a profit in the dairy sector, with farms carrying 80 to 100 cows making a very good living on an efficient system.
Mr Kelly said it was not about carrying large numbers of cows, but more about working efficiently to achieve "extra scale to increase profit".
"Increased numbers in itself is not something that we want to achieve. The reason we would like to see more farmers convert to dairying is it can provide them with a better farm income, and if properly managed, a better lifestyle."
He said that for many farmers, converting to dairying may not require as much investment as stocking sheds could be converted for dairy cow use.
Mr Kelly added another important angle was the extra economic activity filtering down to other sectors and the rural economy.
This activity included contract rearing of dairy heifers, increased employment on dairy farms and increased employment in processing facilities which have undergone a €1bn expansion in recent years.
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