Equine seminal plasma was used in a lactose-EDTA extender for cryopreservation of equine epididymal sperm. Twelve pairs of testicles of slaughtered horses were used. Epididymides were separated and washed applying the retrograde technique to obtain sperm by injecting 10 ml of lactose-EDTA extender through the vas deferens. Samples with more than 30% motility were used. Samples were diluted 1: 1 with the lactose-EDTAextender seminal plasma and filled into 0.5 ml straws at a concentration of 386.3 x 106, frozen in liquid nitrogen and stored for 10 days. The values for fresh and thawed samples were: motility: 43.3 and 16.4% (p<0.05), viability: 48.3 and 40.5%, normal morphology: 67.1 and 56.5%, and integrity of the plasma membrane (HOS): 48.3 and 45.5%.

Equine seminal plasma was used in a lactose-EDTA extender for cryopreservation of equine epididymal sperm. Twelve pairs of testicles of slaughtered horses were used. Epididymides were separated and washed applying the retrograde technique to obtain sperm by injecting 10 ml of lactose-EDTA extender through the vas deferens. Samples with more than 30% motility were used. Samples were diluted 1: 1 with the lactose-EDTAextender seminal plasma and filled into 0.5 ml straws at a concentration of 386.3 x 106, frozen in liquid nitrogen and stored for 10 days. The values for fresh and thawed samples were: motility: 43.3 and 16.4% (p<0.05), viability: 48.3 and 40.5%, normal morphology: 67.1 and 56.5%, and integrity of the plasma membrane (HOS): 48.3 and 45.5%.

Transfection is a process that involves inserting nucleotides into a cell, with the final product being transgenesis. In recent decades different methods have been developed such as biological, physical and chemical processes that have allowed the introduction of nucleotides into cells. In this review, some important aspects of the most used transfection methods in recent years, and their efficiency in the development of the industry, will be addressed. It concludes with an analysis of the ethical debates that have been generated within the field of animal biotechnology.