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. 2023 Feb 2;4(2):155–160. doi: 10.3168/jdsc.2022-0286

Table 2.

Effect of treatment [control = untreated; or treatment with GnRH, or human chorionic gonadotropin (hCG) immediately before embryo transfer (ET)] or ovulation inducers (treatments combined; GnRH+hCG) on pregnancy per ET (P/ET), calving/ET, and pregnancy loss in recipient dairy heifers and lactating cows receiving stage 6 (blastocyst) and stage 7 (expanded blastocyst) fresh in vitro-produced (IVP) embryos or vitrified IVP embryos

Item Treatment
Ovulation inducers (GnRH+hCG) P-value
Control GnRH hCG Treatment Ovulation inducers Parity Treatment × parity Ovulation inducers × parity
Fresh IVP blastocyst embryos
 P/ET 37 d, % (n)
 Overall 46.4 (112) 54.1 (114) 60.2 (108) 58.1 (222) 0.31 0.16 0.002 0.61 0.30
 Nulliparous 51.2 (43)a,b, A,B 67.8 (59)a,b, A,B 74.5 (51)b 70.9 (110) 0.06 0.02
 Primiparous 44.7 (47) 43.3 (30) 48.7 (37) 46.3 (67) 0.90 0.87
 Multiparous 40.9 (22) 44.0 (25) 45.0 (20) 44.4 (45) 0.96 0.78
 Calving/ET,1 % (n)
 Overall 37.4 (107) 42.1 (107) 48.1 (102) 45.0 (209) 0.37 0.30 0.13 0.90 0.95
 Nulliparous 42.5 (40) 51.0 (53) 52.2 (46) 51.2 (99) 0.63 0.34
 Primiparous 35.6 (45) 31.0 (29) 47.2 (36) 40.0 (65) 0.37 0.64
 Multiparous 31.8 (22) 36.0 (25) 40.0 (20) 37.8 (45) 0.86 0.63
 Pregnancy loss,1 % (n)
 Overall 14.9 (47) 21.0 (57) 17.0 (59) 19.0 (116) 0.80 0.66 0.98 0.80 0.21
 Nulliparous 10.5 (19) 21.0 (34) 27.3 (33) 23.9 (67) 0.38 0.11
 Primiparous 15.8 (19) 25.0 (12) 0.0 (17) 10.3 (29) 0.82 0.58
 Multiparous 22.2 (9) 18.2 (11) 11.1 (9) 15.0 (20) 0.82 0.64
Fresh IVP expanded blastocyst embryos
 P/ET 37 d, % (n)
 Overall 60.7 (631)B 60.9 (723)B 56.2 (726)A 58.2 (1,449) 0.14 0.28 <0.001 0.39 0.72
 Nulliparous 65.9 (355) 65.8 (404) 64.8 (400) 65.3 (804) 0.93 0.84
 Primiparous 55.2 (203)a,b, A,B 59.3 (216)b 47.1 (208)a,b, A,B 53.3 (424) 0.04 0.66
 Multiparous 50.7 (73) 44.7 (103) 43.2 (118) 43.9 (221) 0.59 0.31
 Calving/ET,1 % (n)
 Overall 50.0 (608)b 50.3 (684)a,b, A,B 45.0 (689)a,b, A,B 47.6 (1,373) 0.08 0.16 <0.001 0.42 0.41
 Nulliparous 54.2 (343) 55.4 (381) 53.3 (377) 54.4 (758) 0.88 0.97
 Primiparous 45.6 (195)ab 48.6 (208)b 37.6 (197)a 43.2 (405) 0.07 0.57
 Multiparous 41.4 (70) 33.7 (95) 30.4 (115) 31.9 (210) 0.23 0.15
 Pregnancy loss,1 % (n)
 Overall 15.6 (360) 14.2 (401) 16.4(371) 15.3 (772) 0.50 0.55 0.56 0.60 0.49
 Nulliparous 16.2 (222) 13.2 (243) 14.8 (236) 14.0 (479) 0.65 0.44
 Primiparous 14.4 (104) 15.8 (120) 14.9 (87) 15.5 (207) 0.96 0.81
 Multiparous 14.7 (34) 15.8 (38) 27.1 (48) 22.1 (86) 0.29 0.37
Vitrified IVP
 P/ET 37 d, % (n)
 Overall 51.8 (197)A 59.9 (177)B 57.8 (161) 58.9 (338) 0.20 0.08 <0.001 0.74 0.47
 Nulliparous 62.3 (69)A 76.9 (65)B 71.4 (56) 74.4 (121) 0.18 0.08
 Primiparous 48.3 (87) 48.6 (72) 50.8 (65) 49.6 (137) 0.95 0.84
 Multiparous 41.5 (41) 52.5 (40) 50.0 (40) 51.3 (80) 0.5 0.31
 Calving/ET,1 % (n)
 Overall 43.2 (190)A 53.0 (166)B 45.7 (151) 49.5 (317) 0.15 0.13 <0.001 0.42 0.27
 Nulliparous 52.9 (68)a 73.0 (63)b 59.6 (52) 67.0 (115) 0.06 0.06
 Primiparous 39.3 (84) 36.9 (65) 37.7 (61) 37.3 (126) 0.95 0.77
 Multiparous 34.2 (38) 47.4 (38) 39.5 (38) 43.4 (76) 0.50 0.35
 Pregnancy loss,1 % (n)
 Overall 13.7 (95) 7.4 (95) 16.9 (83) 11.8 (178) 0.18 0.99 0.24 0.78 0.56
 Nulliparous 14.3 (42) 4.2 (48) 13.9 (36) 8.3 (84) 0.25 0.31
 Primiparous 15.4 (39) 14.3 (48) 20.7 (29) 17.5 (57) 0.78 0.78
 Multiparous 7.1 (14) 5.3 (19) 16.7 (18) 10.8 (37) 0.50 0.70
a,b

Means within a row with different lowercase superscripts differ (P < 0.05).

A,B

Means within a row with different uppercase superscripts tend to differ (P ≤ 0.10).

1

Pregnant culled animals (n = 153: sold for dairy n = 15; sold for beef n = 70; died n = 68).