[R] Treatment-response analysis along time

[Felix Royo]

Dear R people,
I wonder if you could give me a hand with some of my data. I have a very 
typical analysis in biology, however it is difficult for me to find the 
right way to analyse. I had a group of animals, I gave them a treatment, and 
I measure a variable along time -one´s per day- along 5 days,for 
example(fake data):
Animals Time1 Time2 Time3 Time4
1            1         5        3        1
2            2         7        4        1
3            5         5        3        1
4            1         3        7        2
5            2         7        7        1
Please, notice that all the animals get the same treatment, and there are no 
  control -animals which has no received any treatment.
Normally I handle this kind of data with SPSS and Repeated Measurement 
analysis. That tell me if there is a change along the time, but no 
information about when the treatment start to be effective, when the effect 
has pass. Besides, i would like to be able to handle this data with R.
I have been looking at Crawley's S-plus book, and I cannot find similar 
example as I have, not either in the Dalgaard´s introduction to R, because 
he uses an example where different animals are measured as each time -using 
time as a factor in a one way anova (I am hope I am right).
Thanks for your help and time.
Best regards
Felix