Late estrus or metestrus insemination after estrual inseminations decreases farrowing rate and litter size in swine.

Abstract

A study was conducted with 360 gilts and sows from four herds to determine whether fertility was affected when the final of multiple inseminations was performed in late estrus or metestrus (late insemination). Sows and gilts were inseminated at 24-h intervals immediately after the detection of estrus. After receiving a first insemination, females were paired according to parity and estrus status on d 2 of estrus. Each pair set was inseminated with extended semen from the same semen collection(s). Control females were inseminated once on d 1 if they were not in estrus on d 2 (n = 31) or on both days if they were in estrus on d 2 (n = 149). Late inseminated females in each pair were managed and inseminated in the same manner as control females and then inseminated again 24 h later regardless of estrus status. Overall reproductive performance was similar among the four herds. Late insemination caused a drop in farrowing rate in parity 1 and 2 females (23 and 22%; P < .05 and P < .01, respectively) and average litter size decreased by 1.1 pigs per litter (P < .05) regardless of parity. There were no differences in either litter size or farrowing rate between late inseminated females in estrus and those that were in metestrus at the time of their last insemination.

Characterization of uterine leukocyte infiltration in gilts after artificial insemination

“…It appears that sperm-induced uterine inflammation is a normal physiological response in the mare and serves to clear the uterus from excess spermatozoa and contamination associated with mating (Troedsson, 1997).…”

“…after ovulation), a decrease in fertility can be expected (Rozeboom et al, 1997) The uterine PMN response to semen after insemination differed in both magnitude and duration compared with infusion with extender alone. This resulted in a significant interaction for lavage time after insemination (P < 0.01).…”

032 Use of Triptorelin Acetate for Inducing Ovulation and Facilitating Fixed Time Artificial Insemination of Sows Weaned on Small-Scale and Niche Market Pig Farms

“…Ovulation has been found to occur approximately 70 % of estrus duration (Soede and Kemp, 1997), but it is still variable and difficult to predict because of the absence of any external indication. Any matings occurring too late or too early in relation to ovulation can negatively impact litter size and farrowing rate (Rozeboom et al, 1997). Real-time ultrasonography has been used to determine ovulation onset and duration by identifying ovarian follicle size and changes (Soede et al, 1995;Kemp and Soede, 1996;Soede and Kemp, 1997;Stewart et al, 2010;Knox et al, 2011); however, this method is expensive and impractical for small-scale and niche market swine farms.…”

“…With approximately 95% of sows expressing estrus between 4 and 7 d post-weaning, there is still variability in the WEI and consequently EOI De Rensis et al, 2005). As discussed above, it is well established that fertilization rate (Soede et al, 1995), farrowing rate (Nissen et al, 1997), and litter size (Rozeboom et al, 1997) all depend on AI taking place within 24 h before ovulation. Therefore, producers could benefit from a fixed time in which sows can be inseminated relative to time of ovulation in addition to shortening the WEI.…”

“…Moreover, Soede et al (1995) demonstrated that optimum fertility with AI results when semen is deposited 0 to 24 h before ovulation which results in fertilization rates of greater than 90 %. Inseminations occurring outside of this interval can result in suboptimal pregnancy rates and litter sizes (Soede et al, 1995;Rozeboom et al, 1997). Thus, to increase the likelihood that semen is deposited at the optimum time during estrus, the standard practice is to inseminate 2.5 to 3.0 billion sperm cells at the onset of standing estrus and then again 24 h later (based on once-daily estrus detection).…”