Substituição do feno de capim tifton por palma orelha de elefante mexicana em dietas de novilhas da raça girolando

Abstract

It was aimed to evaluate the replacement of Tifton 85 hay (CynodondactylonL. Pers) by Orelha de Elefante Mexicana cactus (OpuntiastrictaHaw.) in diets of Girolando heifers on intake and digestibility of nutrients, growing performance, microbial protein synthesis, and diet nitrogen utilization efficiency. Twenty-four Girolando (5/8 Holstein x Gir) heifers with an average age of 3.5 months and average body weight of 100 kg (± 3.5kg) were used utilizing a completely randomized design. The intake of dry matter (4,5kg/day -3,65kg/day), organic matter, crude protein, neutral detergent fiber, non-fibrous carbohydrates, and total carbohydrates linearly decreased as a function of the replacement of Tifton 85 hay (TH) by Orelha de Elefante Mexicana cactus (OEMc). The coefficient of digestibility of dry matter linearly increased while the NDF digestibility linearly decreased with OEMc inclusion. There were not significant alterations when growing performance was evaluated by weight gain (0,797kg/day) and morphometric measurements. Urinary volume in addition to nitrogen balance, as well as the efficiency of nitrogen retention linearly increased while urine and serum urea concentrations linearly decreased (1318,99 – 167,24 mg/dl and 29,48 – 10,94 mg/dl, respectively) as a function of TH replacement by OEMc. Given the found results, it is recommended the total replacement of Tifton 85 hay by Orelha de Elefante Mexicana cactus in diets of newly weaned heifers.