Something like
A = randi(9,3,10)
a0 = sum(A,1) % show all column sums as an example
a1 = sum(A(:,1:2:end),1) % odd col sums
a2 = sum(A(:,2:2:end),1) % even col sums
gives
A =
8 2 6 9 3 8 9 3 5 2
9 5 9 1 2 5 4 5 4 4
9 8 9 4 2 9 4 3 3 5
a0 =
26 15 24 14 7 22 17 11 12 11
a1 =
26 24 7 17 12
a2 =
15 14 22 11 11
If you need one or the other, just pick the line you need. If you need to calculate both even and odd column sums, it's generally going to be faster to do it like this, especially for large arrays.
a0 = sum(A,1); % get all column sums at once
a1 = a0(1:2:end); % sort out odd cols
a2 = a0(2:2:end); % sort out even cols
