NON-PREGNANT CYCLE 



PREGNANT CYCLE 



COPULATION NOT PERMITTED COPULATION PERMITTED 



i PROESTRUSi- 



ESTRUS METESTRUS ANESTRU.S -f^ESTRUS PRE G N A N C Y 



VA G I N A L 

 CYCLE 



ERYTHROCYTES 



CORNIFIED EPITHELIAL CELLS 

 LEUKOCYTES 



LINING EPITHELIUM 





MAMMARY 

 GLAND 

 CYCLE 



DAYS 9 



Fig. 54. Changes occurring in the reproductive organs and mammary glands of the 

 bitch during the reproductive cycle. The student is referred to Asdell ('46), pp. 150-156 

 and Dukes ('43), pp. 678 682, for detailed description and references pertaining to the 

 data supporting this chart. The gestation period is based upon data supplied by Kenneth 

 ('43) and the author's personal experience with dogs. 



NON-PREGNANT CYCLE PREGNANT CYCLE 



COPULATION NOT COPULATION PERMITTED 

 i PERMITTED i 



ESTRUS ESTRUS 



115 TO 120 



Fig. 55. Reproductive and pregnancy cycles in the sow. (Modified from data supplied 

 by Corner, Carnegie Inst., Washington, pub. 276, Contrib. to Embryol., 13; the parturition 

 data derived from Kenneth, '43.) 



102 



