17 A. A. Channa M. Aleem M. A. Jabbar H. Monir N. Ahmad1 Journal of Animal and Plant Sciences JAPS 20202020/01/02 30 1 255-258 1018-7081 https://doi.org/10.36899/JAPS.2020.1.0030 <p>Pre-synchronization prior to Ovsynch protocol is an efficient method to improve ovulation and pregnancy rate in dairy cows. The objective of this study was to define the effect of Double-Ovsynch (DOS; GnRH, PGF2&alpha; 7 d later and GnRH 2 d later followed by the OVS protocol with interval of 7 d; timed AI 16 to 24 h after the last GnRH of OVS) and Ovsynch (OVS; GnRH, PGF2&alpha; 7 d later and GnRH 2 d later; timed AI 16- 24 h after the last GnRH) protocols on ovulation and pregnancy rate in crossbred dairy cows. The ovulation rate (day 7 post TAI, DOS<em>&nbsp;n</em>&nbsp;= 20 vs. OVS&nbsp;<em>n&nbsp;</em>= 21) and pregnancy rate (day 35 post TAI, DOS<em>&nbsp;n</em>&nbsp;= 125 vs. OVS&nbsp;<em>n&nbsp;</em>= 148) were determined using ultrasonography. Serum concentrations of progesterone on d 7 after the last GnRH of each protocol was determined in the subset of randomly selected cows (DOS&nbsp;<em>n</em>&nbsp;= 10) and (OVS&nbsp;<em>n</em> =10) protocol. The Ovulation rate (OR) was higher (P &lt; 0.05) in DOS as compared to OVS (90% vs. 47%) protocols. Likewise, pregnancies per AI (P/AI) significantly (P&lt;0.05) increased in DOS as compared to OVS (62 % vs. 30%). Mean serum concentrations of progesterone on d 7 remained similar (P &gt; 0.05) between DOS and OVS (8.68 &plusmn; 0.78 ng/mL: 8.19 &plusmn; 1.85 ng/mL)protocols. It is concluded that DOS compared to OVS yields better ovulation and pregnancy rate in crossbred dairy cows.</p> Ovsynch; Double-Ovsynch; Ovulation; Pregnancy; Crossbred cows Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=AS-18-0055