Evaluation of foal production following intracytoplasmic sperm injection and blastocyst culture of oocytes from ovaries collected immediately before euthanasia or after death of mares under field conditions.

Objective: To evaluate the efficiency of foal production following intracytoplasmic sperm injection (ICSI) and blastocyst culture of oocytes from mares that died or were euthanized under field conditions.

Design: Prospective case series.

Animals: 16 mares (age, 3 to 19 years) that died or were euthanized for various causes.

Activation of equine nuclear transfer oocytes: methods and timing of treatment in relation to nuclear remodeling.

Early development of embryos produced by transfer of equine nuclei to bovine cytoplasts is superior to that of intraspecies equine nuclear transfer embryos. This may be related to differences in chromatin remodeling or efficiency of activation between the two oocyte types. The pattern of donor nucleus remodeling was examined in equine-equine and equine-bovine reconstructed oocytes.

Effects of gas conditions, time of medium change, and ratio of medium to embryo on in vitro development of horse oocytes fertilized by intracytoplasmic sperm injection.

This study was conducted to evaluate the effects of two different gas conditions (5% CO(2) in air or 5% CO(2), 5% O(2), 90% N(2), mixed gas), time of medium change (Day 3 or 4) and ratio of medium to embryo (2, 5 or 10 microl per presumptive zygote) on the development of horse oocytes fertilized by intracytoplasmic sperm injection and cultured in G1.2/2.2 medium.

Effect of ovary storage and oocyte transport method on maturation rate of horse oocytes.

Two experiments were conducted to determine the effects of storage on equine ovaries or isolated oocytes. Ovaries were collected at an abattoir and were maintained at room temperature during collection and transport (3-9h total). After arrival at the laboratory, ovaries were divided into three groups: immediate oocyte collection (control), storage at room temperature overnight (15-18 h) before oocyte collection, or storage at 4 degrees C overnight before oocyte collection.