Large-scale in vitro embryo production and pregnancy rates from Bos taurus, Bos indicus, and indicus-taurus dairy cows using sexed sperm.
Herein we describe a large-scale commercial program for in vitro production of embryos from dairy Bos taurus, Bos indicus, and indicus-taurus donors, using sexed sperm. From 5,407 OPU, we compared the number of recovered oocytes (n = 90,086), viable oocytes (n = 64,826), and embryos produced in vitro from Gir (Bos indicus, n = 617), Holstein (Bos taurus, n = 180), 1/4 Holstein × 3/4 Gir (n = 44), and 1/2 Holstein-Gir (n = 37) crossbred cows, and the pregnancy rate of recipient cows. Viable oocytes were in vitro matured (24 h at 38.8 °C, 5% CO(2) in air) and fertilized by incubating them for 18 to 20 h with frozen-thawed sexed sperm (X-chromosome bearing) from Gir (n = 8) or Holstein (n = 7) sires (2 × 10(6) sperm/dose). Embryos were cultured in similar conditions of temperature and atmosphere as for IVM, with variable intervals of culture (between Days 2 and 5) completed in a portable incubator. All embryos were transferred fresh, after 24 to 72 h of transportation (up to 2,000 km). On average, 16.7 ± 6.3 oocytes (mean ± SEM) were obtained per OPU procedure and 72.0% were considered viable. Total and viable oocytes per OPU procedure were 17.1 ± 4.5 and 12.1 ± 3.9 for Gir cows, 11.4 ± 3.9 and 8.0 ± 2.7 for Holstein cows, 20.4 ± 5.8 and 16.8 ± 5.0 for 1/4 Holstein × 3/4 Gir, and 31.4 ± 5.6 and 24.3 ± 4.7 for 1/2 Holstein-Gir crossbred females (P < 0.01). The mean number of embryos produced by OPU/IVF and the pregnancy rates were 3.2 (12,243/ 3,778) and 40% for Gir cows, 2.1 (2,426/1,138) and 36% for Holstein cows, 3.9 (1,033/267) and 37% for 1/4 Holstein × 3/4 Gir, and 5.5 (1,222/224), and 37% for 1/2 Holstein-Gir. In conclusion, we compared oocyte yield from two levels of indicus-taurus breeds and demonstrated the efficiency of sexed sperm for in vitro embryo production. Culturing embryos during long distance transportation was successful, with potential for international movement of embryos.
Pontes
J H F
JH
Laboratório de Reprodução Animal, DCV-CCA-UEL, Londrina PR, 86051-990 Brazil.
Silva
K C F
KC
Basso
A C
AC
Rigo
A G
AG
Ferreira
C R
CR
Santos
G M G
GM
Sanches
B V
BV
Porcionato
J P F
JP
Vieira
P H S
PH
Faifer
F S
FS
Sterza
F A M
FA
Schenk
J L
JL
Seneda
M M
MM
D000818:Animals; D002417:Cattle / Q000196:embryology*; D046149:Embryo Culture Techniques / Q000662:veterinary*; D004624:Embryo Transfer / Q000662:veterinary; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D018873:Pregnancy Rate; D012732:Sex Determination Analysis / Q000662:veterinary*; D013094:Spermatozoa