When an elite breeding bull dies suddenly, years of selection for growth, fertility and adaptability can be lost with it. But viable sperm can still be recovered from the animal after death and frozen for later use, write Thabang Luther Mashilo of South Africa's Department of Agriculture and Masindi Lottus Mphaphathi of the Agricultural Research Council.
The technique, post-mortem recovery and cryopreservation of epididymal sperm, takes mature sperm directly from the epididymis, the structure attached to the testes where sperm are stored, rather than collecting semen from a living bull with an artificial vagina or electro-ejaculation. The sperm can remain viable for several hours, sometimes up to 24 hours, after death if the testes are handled correctly, and can later be used for artificial insemination or in vitro fertilisation.
Research and practical experience show that such sperm survives freezing and thawing, keeps its fertilising ability and produces viable embryos and healthy calves, the authors say. Conception rates can be slightly lower than with conventionally collected semen, but for an elite bull that difference is usually worth accepting when the alternative is losing the genetics altogether.
Speed and skill decide the outcome. The authors recommend recovery within six to 12 hours of death, carried out by trained personnel, and urge breeders to agree a protocol with a veterinarian or breeding specialist before an emergency happens. Bulls die from accidents, fights, lightning, disease or sudden metabolic failure, often before any semen has been collected.
They argue that protecting locally adapted genetics matters in South Africa's varied beef environments, as input costs rise and the industry needs resilient cattle, and that losing a proven bull otherwise means slower genetic progress and more reliance on costly replacement bulls or imported semen.
Source: Farmers Weekly South Africa
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