Roof rats are the worst rodent pest in the state of Florida and most abundant. The Norway rat (Rattus norvegicus) that is familiar to most people is rare in Florida. Roof rats consume and destroy stored animal and human food, attack fruit crops, and take up residence in attics, soffits, hollow walls, and out-buildings.
1 The sperm brings in another 23 chromosomes to complement the 23 held in the egg to get to a total of 46 chromosomes - what all of us normal people have.  We know from in vitro fertilization studies that the egg is only capable of being fertilized for about 24 hours after ovulation.
Guide. During in vitro fertilization (IVF), eggs and sperm are brought together in a laboratory glass dish to allow the sperm to fertilize an egg. With IVF, you can use any combination of your own eggs and sperm and donor eggs and sperm.ertilization and embryo transfer. The eggs and sperm are placed in a glass dish and incubated with careful temperature, atmospheric, and infection control for 48 to 120 hours. About 2 to 5 days after fertilization, the best fertilized eggs are selected.