Evidence of Platelet Activation Associated with Establishment of Pregnancy in Cows with Transferred Embryos.

Abstract

Abstract. The aims of the present study were twofold. The first aim was to examine whether or not early pregnancy-associated thrombocytopenia (EPAT) occurred in cows following nonsurgical embryo transfer by observing the daily patterns of the concentration of peripheral platelets (PLT) during the preimplantation period of pregnancy. The other goal was to assess the use of PLT count as a diagnosis of early pregnancy in cows. In Experiment 1, out of 50 Holstein parous cows, 40 had one embryo nonsurgically transferred to each uterine horn on Day 6 or 7 (Day 0=onset of standing estrus). The remaining 10 cows served as controls having no embryos transferred. Blood was taken daily at the same time, from Day 6 or 7 following estrus (the day when the embryos were transferred in the non-controls) to the day of return to estrus for control cows and non-pregnant cows, or to Day 36 for pregnant cows. Bilateral embryo transfers resulted in 9 twin, 14 single, and 17 nonpregnancies. Some recipient cows showed an increase in PLT following embryo transfer, while others displayed a decrease in PLT. If significant PLT change was characterized either by a decrease or an increase of >20% compared to the value of pre-transfer, the proportions of cows indicating significant change were 78% (7/9) in twin, 64% (9/14) in single, 76% (13/17) in nonpregnancies and 30% (3/10) in controls. The proportions in twin (P<0.05), single (P<0.05) and nonpregnancies (P<0.01) were higher than that in controls. The effect of the particular group on PLT was significant (P<0.0025). In Experiment 2, each of several in vitro-produced blastocysts were nosurgically transferred to 9 Japanese Black cows on Day 7 or 8 following onset of estrus. Seven days after embryo transfer, an attempt to recover the previously transferred embryos by nonsurgical flushing was performed. Embryos could be recovered on Day 14 or 15 from 5 animals, whose blood was taken from the day of embryo transfer to the next day of embryo recovery and during the corresponding days of the following estrous cycle. For PLT, differences were detected between the both phases of 3 out of the 5 cows. The individual PLT variation in response means that EPAT does not necessarily occur in cows following embryo transfer, and that the use of PLT counts is unlikely to be clinically useful in assessing early pregnancy in cows. These results may suggest, however, that maternal platelet activation would occur during early pregnancy in cattle.

Genome‐wide scan for runs of homozygosity in the composite Montana Tropical® beef cattle

“…The endodermal cell differentiation (GO:0035987) is a biological process related to reproduction, in which relatively unspecialized cells acquire the specialized features of endoderm cells, one of the three germ layers of the embryo. Platelet activation (bta04611) pathway plays a key role for primary homeostasis in the disruption of the integrity of vessel wall and has been associated with the establishment of pregnancy in cows through the maternal platelet activation during early pregnancy (Kojima, Akagi, Zeniya, Shimizu, & Tomizuka, ).…”

Conception and early pregnancy in the mare: lipidomics the unexplored frontier

“…In women, thrombocytopenia occurs in some cases and thrombocytosis (increased platelets) in others ( Yeung et al 1992 ). Localised oviductal platelet consumption has also been seen in both the bovine ( Kojima et al 1996 a ) and rabbit ( Kojima et al 1996 b ), but has not yet been explored in the horse.…”