For those interested in those 40 series Cavalry on the sub-continent.
I used this page of Regiments.org (archieved at the Wayback Machine:
http://web.archive.org/web/200710110.../iargxrefn.htm) to compile:
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40th
Indian Army: 40th Cavalry 1918-1921
Pakistan?: 40th Cavalry 1988?-present
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41st
IndianArmy: 41st Cavalry 1918-1921
India: 41st Cavalry 1980-present
Pakistan: 41st Horse (Frontier Force) 1988-present
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42nd
Indian Army: 42nd Cavalry 1918-1921 and 1941-1943
India: 42nd Cavalry 1981-present
Pakistan?: 42nd Cavalry 1988?-present
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43rd
Indian Army: 43rd Cavalry 1918-1919 and 1941-1946
India: 43rd Cavalry 1981-present
Pakistan?: 43rd Cavalry 1988?-present
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44th
Indian Army: 44th Cavalry 1918-1919 and 1941-1943
India: 44th Cavalry 1981-present
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45th
Indian Army: 45th Cavalry 1918-1919 and 1941-1946
India: 45th Cavalry 1965-present
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46th
Indian Army: 46th Cavalry 1918-1919 and 1941-1942
India: 46th Cavalry 1982-present
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47th
Indian Army: 47th Cavalry 1941-1943
India: 47th Cavalry 1982-present
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48th
Indian Army: 48th Cavalry 1941-1947
India: 48th Cavalry 1982-present
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Remark that the ? there are from the original and that Regiments.org was updated until about 2006 (the "present" above)