DSD 5.3 | Slight modifications of CIDR Sync - help or hinder? In this time of heifer inventory shortage – getting heifers pregnant (in a timely fashion) is even more important than ever.Contract heifer growers in California sought the help of Dr. Fabio Lima and his team at UC Davis to best understand the use of a 6-day CIDR sync with variable rates of GnRH could increase pregnancies when bred to sexed semen.The findings we discuss are published in the recently released Journal of Dairy Science article titled: Effect of 200 μg of gonadorelin hydrochloride at the first GnRH of a CIDR Synch program on  ovulation rate and pregnancies per AI in Holstein heifers.Listen in to hear the results and nuanced details of controlling reproductive structures using timed AI protocols.Topics of discussionArticles also discussed in the podcast:Heifer study using 100 and 200 ug in 5-d CIDR Synch protocol. https://doi.org/10.1016/j.theriogenology.2023.04.026Studies showing the implication of progesterone for double ovulation (a proxy for twining) and progesterone. https://doi.org/10.3168/jds.2018-14410   #2xAg2030; #journalofdairyscience; #openaccess; #MODAIRY; #gnrh; #CIDRsync; #twinning; #pregnancy; #heiferdevelopment; #TAI; #lutenizing; #dairysciencedigest; #ReaganBluel;