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Table 2 Mean plasma P4 concentrations and ISG15 abundance according to reproductive status in beef cows

From: Exacerbated conceptus signaling does not favor establishment of pregnancy in beef cattle

Variable iP4a Non-iP4 P value
Pregnantb (n = 10) EEM (n = 12) LEM (n = 5) Pregnant (n = 15) EEM (n = 6) LEM (n = 6) iP4 Group iP4× Group
Mean plasma P4 concentrations, ng/mL
D4, D5 and D7 3.21 ± 0.44 4.01 ± 0.38 2.77 ± 0.59 3.17 ± 0.34 2.56 ± 0.54 2.01 ± 0.54 0.04 0.11 0.22
D14 to D20 7.19 ± 0.70 . 4.89 ± 0.94 6.79 ± 0.58 . 6.76 ± 0.86 0.35 0.15 0.16
Mean ISG15 abundance in PBMCs
D14 to D20 5.02 ± 0.58 0.76 ± 0.53 3.42 ± 0.82 3.49 ± 0.47 0.76 ± 0.74 3.78 ± 0.74 0.48 < 0.001 0.37
D20 8.56 ± 1.24 1.27 ± 1.31 5.56 ± 1.76 5.79 ± 1.02 0.72 ± 1.97 6.39 ± 1.61 0.50 < 0.001 0.52
  1. EEM = early embryonic mortality; LEM = late embryonic mortality
  2. aBeef cows detected in estrus (D0) were assigned randomly to receive a single injection of vehicle (Non-iP4) or 150 mg of long acting progesterone (iP4) on D
  3. 4 and transfer of 5 in vitro produced blastocysts on D7. Conceptus signaling was monitored by abundance of ISG15 in peripheral blood mononuclear cells (PBMCs) isolated on D14, D16, D18 and D20. Blood samples were collected on D4, D5 and D7 and from D14 to D20, every d, for P4 assay
  4. bCows were classified retrospectively as experiencing early embryonic mortality (EEM), late embryonic mortality (LEM) or diagnosed as pregnant by presence of at least one conceptus with heartbeat at ultrasound exam on D30. Cows were included in the EEM group when there was no evidence of conceptus presence up to D16 according to absence of ISG15 mRNA increase between D14 and D20 and/or incidence of luteolysis before D20. Conversely, cows classified as LEM presented a clear increase on ISG15 abundance, functional CL on D30, but no evidence of viable conceptus (i.e. with heartbeat) on D30. Means of variables over time were considered for analysis including the effect of iP4 supplementation, group and interaction. Results are reported as Least squares means ± SEM