Inheritance of resistance of XXXX preimplantation embryos to @entity1457 : relative importance of the maternal versus paternal contribution.

@entity1457 @entity1442 @entity2085 @entity291
Brahman preimplantation embryos are less affected by exposure to @entity1457 than Holstein embryos. Two experiments were conducted to test whether the ability of Brahman embryos to resist the deleterious effects of @entity1457 was a result of the genetic and cellular contributions from the oocyte, spermatozoa, or a combination of both. In the first experiment, Brahman and Holstein oocytes were collected from slaughterhouse ovaries and fertilized with spermatozoa from an Angus bull. A different bull was used for each replicate to eliminate bull effects. On day 4 after fertilization, embryos >or= 9 cells were collected and randomly assigned to control (38.5 degrees C) or @entity1457 (41 degrees C for 6 hr) treatments. The proportion of embryos developing to the @entity2085 ( @entity2085 ) and @entity1442 ( @entity1442 ; expanded and hatched) stages was recorded on day 8. @entity1457 reduced the number of embryos produced from Holstein oocytes that developed to @entity2085 (P < 0.001, 55.6 +/- 4.2% vs. 29.8 +/- 4.2%) and @entity1442 (P < 0.01, 37.7 +/- 3.6% vs. 12.2 +/- 3.6%) on day 8 as compared to controls. In contrast, @entity1457 did not reduce development of embryos produced from Brahman oocytes ( @entity2085 = 42.1 +/- 4.8% vs. 55.6 +/- 4.8% for 38.5 and 41 degrees C, respectively; @entity1442 = 17.6 +/- 4.2% vs. 32.4 +/- 4.2%). In the second experiment, oocytes from Holstein @entity291 were fertilized with semen from bulls of either Brahman or Angus breeds. @entity1457 of embryos >or= 9 cells reduced development to @entity2085 (P < 0.002) and @entity1442 (P < 0.005) for embryos sired by both Brahman ( @entity2085 = 54.3 +/- 7.7% vs. 23.4 +/- 7.7%; @entity1442 = 43. +/- 7.4% vs. 7.9 +/- 7.4%, for 38.5 and 41 degrees C, respectively) and Angus bulls ( @entity2085 = 57.9 +/- 7.7% vs. 31.0 +/- 7.7%; @entity1442 = 33.6 +/- 7.4% vs. 18.4 +/- 7.4%, for 38.5 and 41 degrees C, respectively). There were no breed x temperature interactions. Results suggest that the oocyte plays a more significant role in the resistance of Brahman embryos to the deleterious effects of @entity1457 than the spermatozoa.
