The aim of this study was to verify the incidence of late embryonic mortality (between
25 and 45 days post-insemination; LEM) and foetal mortality (between 45 and 70 days postinsemination;
FM) in buffaloes synchronized and mated by AI during the transitional period. The
trial was performed on 288 multiparous Mediterranean Buffaloes, synchronized and inseminated by
AI. Trans-rectal ultrasonography was performed 25, 45, and 70 days post-insemination to assess embryonic
development. Milk samples were collected on Days 10, 20, 25, 30, and 45 post-insemination to
determine progesterone concentration in whey. Pregnancy rate on Day 25 after AI was 48.6% but declined
to 35.4% and to 30.6% by Day 45 and 70 respectively, representing a LEM of 27.1% and a FM of
13.7%. Progesterone concentration was higher (P<0.01) in pregnant compared to LEM buffaloes after
20 days post-insemination. Differences (P<0.05) were found between FM and LEM buffaloes on Days
25 and 30. Furthermore, progesterone concentration in pregnant buffaloes was higher (P=0.09) than
that of FM buffaloes on Day 30 and 45. In conclusion, the success of application of reproductive biotechnologies
in the transitional period depends from the incidence of embryonic and foetal mortality
