Effect of IVPRD, estradiol and GnRH for resynchronization on fertility of non-pregnant Holstein dairy cows

Abstract

The aim of this study was to evaluate the effect of intra vaginal progesterone releasing device (IVPRD), estradiol and GnRH for resynchronization on fertility of non-pregnant Holstein dairy cows. Non-pregnant cows (n = 117) were divided into three groups. The first group (n = 38) was treated with Ovsynch [GnRH, day 0; PGF2α, day 7; GnRH, day 9; timed artificial insemination (TAI), day 10]. The second group (n = 39) was treated with cue-mate-estradiol benzoate (EB) (cue-mate intra vaginal insertion and first EB, day 0; PGF2α, day 7; cue-mate withdrawn and second EB, day 8; TAI, day 10). The third group (n = 40) was treated with PG (PGF2α, day 0; AI after heat expression). The trial was conducted from September 2014 to March 2015. Milk sampling was done for each cow 14, 21 and 24 days after resynchronized AI for analysis of progesterone concentration. Conception rate was significantly decreased (P < 0.05) with IVPRD and EB compared to with PG. In contrast, in the Ovsynch and cue-mate-EB treatment groups, return to estrus tended to be higher than in the PG group (P = 0.05). In conclusion, the reproductive performance in the PG group was better than in the cue-mate-EB group, but was similar to that in the Ovsynch group.