Growth rate of weaned lambs grazing brown midrib sorghum (Sorghum bicolor) supplemented with increasing levels of soybean meal
L. Piaggio A C , M. de J. Marichal B , M. L. del Pino A and H. Deschenaux AA Secretariado Uruguayo de la Lana, Rambla Baltasar Brum 3764, Montevideo, Uruguay.
B Facultad de Agronomía, Universidad de la República, Garzón 780, Montevideo, Uruguay.
C Corresponding author. Email: lpiaggio@adinet.com.uy
Animal Production Science 54(9) 1278-1281 https://doi.org/10.1071/AN14190
Submitted: 11 March 2014 Accepted: 16 May 2014 Published: 10 July 2014
Abstract
The aim of the present study was to describe the relationship between increasing levels of soybean meal (SBM) supplementation and the growth rate of weaned lambs grazing brown midrib (BMR) sorghum. Sixty Corriedale weaned lambs (3 months old) were divided into 12 homogeneous groups and allocated into three blocks of BMR sorghum (stocking density: 50 lambs/ha) of four plots each. In each block, lambs were assigned (5 lambs/plot.block) to one of the following treatments: grazing sorghum, grazing sorghum + 115 g SBM/lamb.day, grazing sorghum + 230 g SBM/lamb.day, and grazing sorghum + 345 g SBM/lamb.day. Rotational grazing management was implemented. Lambs were weighed at the beginning of the experiment. Final bodyweight and average daily gain (ADG) were analysed according to a completely randomised block design. The relationship between SBM supplementation level and ADG was tested and a non-linear fit with a prediction model of first-order kinetics was determined. Supplemented lambs had a higher (P < 0.036) final bodyweight and presented higher (P < 0.001) ADG than did non-supplemented lambs (31 kg and 120 g/lamb.day vs 26 kg and 55 g/lamb.day in supplemented and non-supplemented lambs, respectively). An asymptotic ADG value estimated by the model of 143.26 g/lamb.day BMR sorghum appeared to be an adequate summer grazing alternative for weaning lambs. SBM supplementation would improve the performance of animals however the level of supplementation would depend on the productive goal.
Additional keywords: performance, protein supplementation, sheep.
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