Replicare rows in Matrix : I ve a Matrix 
A<- 
DOG.            4
CAT.             3
MOUSE.      6
PIG.             1
HORSE.       9

Names of animals are rownames 
Now I 've the matrix 
B <- 
             A1.   A2.     A3.    A4.      A5.    A6.    
AGE.       16.    15.    4.       9.         11.    12

I would to replicate the row age for how many are the rownames in matrix A.

Example:
                 A1.   A2.     A3.    A4.      A5.    A6.    
DOG.       16.    15.    4.       9.         11.    12
CAT          16.    15.    4.       9.         11.    12
MOUSE    16.    15.    4.       9.         11.    12 
HORSE     16.    15.    4.       9.         11.    12
PIG            16.    15.    4.       9.         11.    12

Suggestions?