Lamb feedlot mortalities: The rumen development link

The South African sheep feedlot industry annually produces approximately 180 000 tons of lamb and mutton with an estimated value of R7 billion.

- The Nutro Company

The Northern and Western Cape slaughter 62% of all sheep produced in South Africa. The Northern Cape, Eastern Cape and Free State combined produce 75% of all sheep slaughtered, while the Western Cape produces 12%. Just short of 400 000 sheep are slaughtered on average per month with lamb carcasses accounting for around 80% of all sheep carcasses. From November 2022 to October 2023, a total of 4 456 203 sheep were slaughtered through formal channels. The feedlot industry is therefore a key component of the sheep value chain and sheep producers are dependent on this leg of the industry to remain profitable. It is in the interest of the primary producer to consistently supply the feedlot with healthy, resilient lambs with a high growth potential.

Problem description

The number of lambs unable to adapt in a feedlot environment have, however, increased significantly over recent years. This manifests in abnormally high lamb mortalities. The reported cause of death in these animals is often attributed to lung infections indicating poor immunity and inability to handle the stress of transport and adaption to high concentrate diets. Apart from elevated mortalities, a substantial number of lambs are slaughtered early due to poor growth. Feedlot losses are therefore not only because of mortalities, but also a high number of small carcasses that do not meet consumer demand.

The sources of these poor-quality lambs seem to be extensive farms, specific geographical areas, and possibly farms with similar production systems. The source is currently not confined to a specific biome, but since the Central Karoo and Eastern Cape is the largest sheep producing areas, large numbers of compromised lambs originate from these regions. This phenomenon also affects certain batches of lambs originating from Namibia and the Northern Cape.