Fertility of lactating Holstein cows submitted to a Double-Ovsynch protocol and timed artificial insemination versus artificial insemination after synchronization of estrus at a similar day in milk range

Abstract

Our objective was to compare the AI submission rate and pregnancies per artificial insemination (P/AI) at first service of lactating Holstein cows submitted to a Double-Ovsynch protocol and timed artificial insemination (TAI) versus artificial insemination (AI) to a detected estrus after synchronization of estrus at a similar day in milk range. Lactating Holstein cows were randomly assigned to receive their first TAI after a Double-Ovsynch protocol (DO; n = 294) or to receive their first AI after a synchronized estrus (EST; n = 284). Pregnancy status was determined 33 ± 3 d after insemination and was reconfirmed 63 ± 3 d after insemination. Data were analyzed by ANOVA and logistic regression using the MIXED and GLIMMIX procedures of SAS (SAS Institute Inc., Cary, NC). By design, days in milk at first insemination did not differ between treatments (76.9 ± 0.2 vs. 76.7 ± 0.3 for DO vs. EST cows, respectively), but more DO cows were inseminated within 7 d after the end of the voluntary waiting period than EST cows (100.0 vs. 77.5%). Overall, DO cows had more P/AI than EST cows at both 33 d (49.0 vs. 38.6%) and 63 d (44.6 vs. 36.4%) after insemination, but pregnancy loss from 33 to 63 d after insemination did not differ between treatments. Primiparous cows had more P/AI than multiparous cows 33 and 63 d after insemination, but the treatment by parity interaction was not significant. Synchronization rate to the hormonal protocols was 85.3%, which did not differ between treatments; however, synchronized DO cows had more P/AI 33 d after insemination than synchronized EST cows (54.7 vs. 44.5%). In summary, submission of lactating Holstein cows to a Double-Ovsynch protocol and TAI for first insemination increased the percentage of cows inseminated within 7 d after the end of the voluntary waiting period and increased P/AI at 33 and 63 d after first insemination resulting in 64 and 58% more pregnant cows, respectively, than submission of cows for first AI after detection of estrus at a similar day in milk range. We conclude that, because the proportion of synchronized cows did not differ between treatments, DO cows had more P/AI than EST cows because of an intrinsic increase in fertility after submission to a fertility program.

Fertility of Lactating Jersey X Holstein-Friesian Cows in Subtropical Region Submitted to a Double-Ovsynch Versus Ovsynch Protocol for 1timed Artificial Insemination

“…Serum progesterone concentrations after 7-days from last GnRH in each protocol was similar i.e., DOS; 8.68 ± 0.78 and OVS 8.19 ± 1.85 ng/mL (P>0.05). The suitability and successful induction of the DOS in various synchronization regimens has previously been reported in Holstein cows to improve the ovulation rate and fertility (Souza et al 2008,Herlihy et al 2012, Santos et al 2017. Similarly, the findings of our study support the hypothesis that by using DOS protocol pregnancy rate in crossbred dairy cows can be enhanced under subtropical conditions.…”

Comparative Study of Pregnancy Rate of Dairy Cows Inseminated with Fresh or Frozen-Thawed Semen

“…In the study by Neves et al (2012) the overall reproductive performance was found to be similar between management based on automated activity monitoring (AAM) and a synchronization program for TAI, including Ovsynch, Presynch or Co-Synch. Double-Ovsynch treatment appears to increase CR to the maximum currently attainable level (Souza et al, 2008;Herlihy et al, 2012;Neves et al, 2012;Santos et al, 2017). Hence our results are not consistent with Denis-Robichaud et al (2018) who reported improved CR if Double Ovsynch protocol was administered (36.3%) rather than application of the AAM system (32%).…”

An automated controlled-release device for intravaginal hormone delivery

“…Therefore, a method used by many commercial farms to submit cows for insemination consists of synchronizing ovulation followed by timed AI (TAI; Pursley et al, 1995Pursley et al, , 1997. Benefits of TAI include insemination at a predetermined time regardless of expression and detection of estrus and the possibility of achieving similar or greater fertility than that of AI at detected estrus (Pursley et al, 1997;Santos et al, 2017). A major caveat of implementing TAI programs is the need to administer multiple hormonal treatments as intramuscular (IM) or subcutaneous injections.…”