Abstract The Hannoverian Sport Horse Breeding Association registers about 16 000 brood-mares, 9500-10 000 of which are yearly booked to the stallions of the Landgestüt Celle. This is a state-owned depot where 180 active sires are kept and offered for breeding service for mares kept in farms throughout the Lower Saxon county. The other brood-mares are served by stallions owned privately, competing with the Celle stallions. Each year, 10% of the stallions are recruited from a selected and intensely tested group of young stallions. During the breeding season — late January to late July—the sires are stabled in breeding subcenters where they serve as semen donors for AI (10 locations) or for natural breeding (38 locations). In the subcenters for AI, semen is processed for fresh, cooled and shipped semen transfer. Stallions, selected for breeding, undergo a strict prebreeding and breeding health management program. AI is performed mainly by using fresh cooled semen, and only occasionally by frozen semen. Stallions are not allowed to serve simultaneously in artificial and natural breeding. Semen collection is confined to one single collection per day and per stallion to adjust daily sperm output to a predictable level. The number of sperm cells per insemination dose is set at 5 × 10 8 progressively motile spermatozoa. The insemination volume varies from 10 to 30 cm −3. Semen is extended with skim milk extender ( Kenney et al., 1975) or in a glycine-egg-yolk extender ( Van der Holst, 1984) with or without removal of seminal plasma following centrifugation of the semen. A new container for shipment has been developed which maintains the preferred temperature of 5 °C up to 36 h. Fertility results from AI with fresh semen are 67.1% registered foals, i.e. almost a five points better result than those obtained after natural breeding (62.8 registered foals) during the last three seasons preceding the introduction of AI. The use of AI tends to become progressively the zootechnique of equine breeding practice in almost all of the horse breeds except the thoroughbred. AI systems for frozen semen and some systems using fresh semen have been presented for practical use in the field.