Mortalidad en un feedlot de La Plata (Buenos Aires, Argentina): causas, distribución mensual e impacto económico

Los objetivos del presente trabajo fueron evaluar las causas de muerte, la distribución mensual, la tasa de mortalidad y las pérdidas económicas en un engorde a corral comercial de La Plata (Buenos Aires, Argentina). Se registraron las muertes diariamente y se realizaron las necropsias correspondientes durante todo el año 1999. En total se revisaron 18.695 animales y se realizaron 129 necropsias. La mortalidad anual fue de 0.69% y la mortalidad mensual promedio fue de 0.216%. El 74% de las muertes se registró entre febrero y mayo. El riesgo relativo de muerte fue 3 veces mayor durante el período de adaptación (<30 días en el feedlot) comparado con el producido durante el período de terminación (>30 días en el feedlot). Las muertes de origen tóxico (37%) y respiratorio (29.9%) fueron las más importantes en adaptación, mientras que en terminación fueron las de origen digestivo (68%). La intoxicación con monensina, la bronconeumonía y la acidosis ruminal significaron el 68.9% de las muertes. El 92,2% de las muertes se pueden prevenir mediante vacunas o correcciones de manejo. Por último, una muerte costó 351,2$ en adaptación y 717,9$ en terminación, y en total, en ese feedlot durante 1999 se perdieron 57039,2$ por las 129 muertes. The objectives of the present study were to assess mortality rate, causes of death, monthly distribution of deaths, and economic impact of deaths in a feedlot from La Plata, Argentina during 1999. The commercial feedlot had a mean monthly population of 4931 (SD: 981). Animals were Angus, Hereford and Angus x Hereford, initial bodyweight was 170 ? 210 kg, feeding period was 70 ? 90d, and final bodyweight was 280 ? 330 kg. Pens were checked twice daily by feedlot personnel, and dead animals were recorded and necropsied. A total of 52700 beef cattle heads were evaluated, and 129 necropsies were recorded and performed. Study population was divided into 1) Adaptive period (<30d on feedlot) and 2) Fattening period (>30d on feedlot). Mortality rate was assessed in annual and monthly basis. Deaths were classified according to causative origin and their preventable nature. Finally, relative risk for death and financial loss associated with mortality were estimated. Annual mortality rate was 0.69% and monthly mortality rate was on average 0.216 %. Seventy five % of death losses occurred in adaptive period and the remaining 25% in fattening period. Seventy four % of death losses occurred from February through May. Toxic and digestive deaths (37 and 30 %, respectively) were the most important in adaptive period, while digestive deaths (68%) were the most common in fattening period. Monensin toxicity, rumen acidosis and bronchopneumonia caused 68.9 % of total death losses. Ninety two point two % of deaths were classified as preventable death. The relative risk for death was 3 times higher during the adaptive period than in the fattening period. A dead animal caused a loss of $351.2 in adaptive period, and $717.9 in fattening period. In sum, the 129-recorded deaths represented a loss of over $57000. In conclusion, it is recommended for this feedlot to adopt a health program, firstly, because dead animals are costly, and secondly, because most deaths can be prevented. Facultad de Ciencias Veterinarias (FCV)