In vitro fertilization (IVF) from low or high antral follicle count pubertal beef heifers using semi-defined culture conditions

Authors: Chase, Chadwick - Chad; Cushman, Robert - Bob; McNeel, Anthony; Wright, Elane; AMUNDSON, OLIVIA - South Dakota State University; LARIMORE, E - South Dakota State University; RICHARDSON, B - South Dakota State University; PERRY, GEORGE - South Dakota State University; TENLEY, S - University Of Nebraska; WOOD, J - University Of Nebraska; CUPP, ANDREA - University Of Nebraska; Vallet, Jeff; Sypherd, David; Miles, Jeremy

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/18/2015
Publication Date: 7/1/2015
Citation: Chase Jr., C.C., Cushman, R.A., McNeel, A.K., Wright-Johnson, E.C., Amundson, O.L., Larimore, E.L., Richardson, B.N., Perry, G.A., Tenley, S.C., Wood, J.R., Cupp, A.S., Vallet, J.L., Sypherd, D.D., Miles, J.R. 2015. In vitro fertilization (IVF) from low or high antral follicle count pubertal beef heifers using semi-defined culture conditions [abstract]. Journal of Animal Science. 93 (Supplement s3):424.

Interpretive Summary:

Technical Abstract: Antral follicle counts (AFC) vary among pubertal beef heifers. Our objective was to compare the in vitro maturation and fertilization of oocytes collected from low and high AFC heifers. Previously we reported results using serum-based IVF media and in this study report results using semi-defined media. From a pool of 120 heifers, 10 low and 10 high AFC heifers determined by transrectal ultrasonography and all with evidence of estrous cyclicity (i.e., pubertal) were synchronized with two injections of PGF2a and sacrificed over 4 d; on d 5 to 6 of the estrous cycle. Nineteen heifers (n = 9 low and n = 10 high AFC) were at the appropriate stage of the estrous cycle. The IVF procedures and media were as described (P.J. Hansen’s Laboratory, IVP Protocol). Cumulus-oocyte complexes (COCs) from follicles less than 8 mm in diameter were cultured in maturation medium (5% CO2; 38.5°C) for 24 h. Matured COCs were fertilized using thawed frozen semen from a crossbred bull that was purified using Percoll separation procedures. Motile spermatozoa were added to COCs in fertilization medium at a final concentration of 1 x 106 spermatozoa per mL. About 24 h later, presumptive zygotes were placed in micro drops of development medium under oil, and cultured (5% CO2; 5% O2; 38.5°C). On d 3 and 8 after fertilization, cleavage and blastocyst development, respectively, were assessed. Data were analyzed using the MIXED procedure of SAS and the model included the effects of collection d, group, and their interaction. Percentage data were analyzed using the GLIMMIX procedure with a binomial distribution and a logit link. Neither collection d nor the interaction differed (P = 0.13). High compared to low AFC heifers had greater numbers of COCs (P < 0.01; 27.0±3.79 vs. 9.6±3.97 per heifer), oocytes that cleaved (P < 0.04; 15.2±2.63 vs. 6.1±2.76 per heifer), and developed to blastocysts (P < 0.007; 4.08±0.662 vs. 0.83±0.695 per heifer). There was no difference (P > 0.9) in the percentage of COCs that cleaved (low = 52.3±8.37%, high = 53.6±7.98%) or in the percentage of COCs that developed to blastocysts (P < 0.13; low = 6.6±2.79% vs. high = 13.7±2.66). These results agree with our previous findings using serum-based media; high AFC heifers had greater numbers of COCs, oocytes that cleaved, and blastocysts compared to low AFC heifers; however, AFC does not appear to affect oocyte development and maturation through the blastocyst stage.