Pregnancy-specific protein B in serum of postpartum beef cows

Abstract

To determine whether the uterus was the source of serum pregnancy-specific protein B (PSPB) after calving, five beef cows were hysterectomized at 21 d postpartum and five served as intact controls. A single blood sample was taken from all cows immediately after calving and then twice weekly until 21 d postpartum. Beginning on d 22, blood samples were taken from all cows at 3-h intervals for 4 d and then twice weekly until 53 d postpartum. When the half-life calculated for the interval from d 1 to 21 was used as a covariate, the adjusted d-22 to -53 half-lives were 8.4 d for control cows vs 7.3 d for hysterectomized cows (P = .044). Data show that PSPB has a long half-life in the circulation and that the uterus is a minimal, if any, source of postpartum circulating PSPB. In another experiment, PSPB was measured weekly after calving in serum of 58 Polled Hereford and Simmental cows. Cows were exposed to fertile bulls and allowed to mate at every estrus. Observations were made for estrus, and progesterone concentrations in serum were measured to estimate the time of ovulations. Levels of PSPB were highest at approximately the time of calving, then decreased rapidly. Concentrations of PSPB were < 1 ng/mL by 80 d in eight cows that had not conceived since calving. Two cows eventually had nondetectable PSPB levels, one by 86 d and the other by 96 d after calving.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression profile and protein levels of placental products as indirect measures of placental function in in vitro-derived bovine pregnancies

“…5a). Conversely, as bPSPB has a rather long half-life, with its plasma levels still detectable 3 months or more after parturition (Sasser et al 1986, Kiracofe et al 1993, neonatal plasma concentrations remained elevated throughout the period under scrutiny (24 h) following parturition (Fig. 5b).…”

“…Gene and cDNA sequencing have shown identical homology between PSPB and PAG-1, with both proteins differing only in glycosylation and sialic acid contents (Xie et al 1991, Lynch et al 1992. Concentrations of bPSPB in maternal plasma can be detected from early stages of gestation, during early placentation, to increase gradually throughout pregnancy and reach peak values immediately before parturition (Sasser et al 1986, Kiracofe et al 1993. Despite the unknown function and control of PSPB secretion, many potential biological functions have been suggested based on in vivo and in vitro effects, including prostaglandin release by the endometrium, implantation, immunotolerance of the conceptus as a tissue alograft and uterine remodelling after parturition, among others (Del Vecchio et al 1990, Kiracofe et al 1993, Austin et al 1999, Tefera et al 2001.…”

“…Concentrations of bPSPB in maternal plasma can be detected from early stages of gestation, during early placentation, to increase gradually throughout pregnancy and reach peak values immediately before parturition (Sasser et al 1986, Kiracofe et al 1993. Despite the unknown function and control of PSPB secretion, many potential biological functions have been suggested based on in vivo and in vitro effects, including prostaglandin release by the endometrium, implantation, immunotolerance of the conceptus as a tissue alograft and uterine remodelling after parturition, among others (Del Vecchio et al 1990, Kiracofe et al 1993, Austin et al 1999, Tefera et al 2001. Both PAG-1 and PSPB diagnostic assays have been developed for early plasma diagnosis of pregnancy in cattle and other ruminants (Sasser et al 1986, Zoli et al 1991, Green et al 2000.…”

Recent Possibilities for the Diagnosis and Pharmacological Control of Pregnancy Loss in Dairy Cow

“…Both bPSPB and bPAG1 have been detected in peripheral circulation during the postpartum period 70 to 100 days after calving [27,30]. In a recent study, 56.7% and 44.9% of the false positive diagnoses based on bPSPB and bPAG1 tests, respectively, originated from cows that were inseminated within 70 days after calving [15].…”

“…According to a recent study in herds with a high incidence of EFM of a non-infectious nature at PD (days [28][29][30][31][32][33][34], treatment at the time of PD with progesterone in cows with one corpus luteum and with GnRH in cows with two or more corpora lutea should offer considerable benefits [102]. …”