Effect of naloxone on post-partum ovariesa？？ follicular size in holstein cows

Pulsatile release of luteinizing hormone (LH) in postpartum cows is relatively rare immediately after parturition and its occurrence increases as time of first ovulation approaches by naloxone. The main objective of this study was to assessment of naloxone on post-partum ovaries’ follicular size in Holstein cows. In this study, 60 dairy cows were selected and divided into 3 identical groups by chance. Control group received no treatment, but two others, received 20 and 30 mg naloxone respectively. Results showed that there is significant difference among control and treatments (P<0.001) which is not observed between treatments (P>0.05). Finally can declare that opioids are close relationship with GnRH secretion and can be used in the animal breeding for obtaining better results in post-partum period