Integrated crop-livestock systems in semiarid regions improve sheep performance compared to traditional use of natural rangelands: Nutrient digestibility, biochemical parameters, microbial protein and carcass traits

Integrated crop-livestock (ICL) systems have been proposed as an alternative production strategy in semiarid regions. This study evaluates nutrient intake and digestibility, metabolic profile, microbial protein synthesis, performance, carcass traits, and commercial cuts of sheep raised in different ICL systems in semiarid regions compared to those raised on an exclusive natural rangeland. The treatments included three ICL systems implemented in the Caatinga, comprised of sheep livestock integrated with (i) bean crops, (ii) maize crops, and (iii) herb-cotton crops. The control treatment consisted of exclusive Caatinga rangeland. The experiment, conducted over two years in a thinned Caatinga site enriched with Buffel and Urochloa grasses, involved 24 non-castrated male lambs (Santa Ines × Dorper F1 crossbred) each year. The experimental design was completely randomized, with four treatments (three ICL systems and one control treatment) and six replicates (six sheep per treatment per year), with years treated as a fixed effect. ICL systems increased (P<0.05) the digestibility of nutrients, microbial protein synthesis, serum glucose and urea concentrations, weight gain, and carcass traits. Thus, under the conditions of this study, the use of natural rangelands integrated with bean or herb-cotton crops is recommended, as it favors the intake and digestibility of nutrients, increases serum glucose and urea concentrations, in addition to increasing the microbial protein synthesis , resulting, consequently, in better productive performance and superior carcass traits of Santa Ines × Dorper F1 crossbred grazing lambs.