Spineless Cactus plus Urea and Tifton-85 Hay: Maximizing the Digestible Organic Matter Intake, Ruminal Fermentation and Nitrogen Utilization of Wethers in Semi-Arid Regions
Robert E. Mora-Luna,
Ana M. Herrera-Angulo,
Michelle C. B. Siqueira,
Maria Gabriela da Conceição,
Juana C. C. Chagas,
Carolina C. F. Monteiro,
Antonia S. C. Véras,
Francisco F. R. Carvalho,
Marcelo A. Ferreira
Affiliations
Robert E. Mora-Luna
Deanship of Research, Coordination of Agricultural Research, National Experimental University of Táchira (UNET), San Cristobal 5001, Táchira, Venezuela
Ana M. Herrera-Angulo
Deanship of Research, Coordination of Agricultural Research, National Experimental University of Táchira (UNET), San Cristobal 5001, Táchira, Venezuela
Michelle C. B. Siqueira
Department of Animal Science, Federal Rural University of Pernambuco (UFRPE), Recife 52171900, PE, Brazil
Maria Gabriela da Conceição
Department of Animal Science, Federal Rural University of Pernambuco (UFRPE), Recife 52171900, PE, Brazil
Juana C. C. Chagas
Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences (SLU), 90183 Umea, Sweden
Carolina C. F. Monteiro
Department of Animal Science, Federal Rural University of Pernambuco (UFRPE), Recife 52171900, PE, Brazil
Antonia S. C. Véras
Department of Animal Science, Federal Rural University of Pernambuco (UFRPE), Recife 52171900, PE, Brazil
Francisco F. R. Carvalho
Department of Animal Science, Federal Rural University of Pernambuco (UFRPE), Recife 52171900, PE, Brazil
Marcelo A. Ferreira
Department of Animal Science, Federal Rural University of Pernambuco (UFRPE), Recife 52171900, PE, Brazil
The aim of this study was to evaluate the effect of replacing Tifton-85 hay (Cynodon spp. cv. Tifton 85) with 0, 150, 300, 450 and 600 g/kg dry matter (DM) of spineless cactus (SC, Nopalea cochenilifera Salm-Dyck) plus urea and ammonium sulfate (UAS; 9:1) on DM, digestible organic matter (DOM) and indigestible neutral detergent fiber (iNDF) intakes, as well as ruminal fermentation, N-balance, and microbial protein supply (MPS). Five rumen-fistulated and cannulated crossbred wethers, weighing 43.8 ± 5.80 kg, were randomized in a 5 × 5 Latin square design. Isonitrogenous diets (14% crude protein) were supplied with a roughage/concentrate ratio of 70:30. The DOM intake, N-retained, and MPS showed quadratic responses (p 0.05), with maximum values estimated at the levels of SC+UAS of 414, 438 and 418 g/kg DM, respectively. Rumen pH and ammonia nitrogen, iNDF intake, N-urinary excretion, and serum urea and plasma ammonia reduced linearly (p 0.05) with increasing SC+UAS inclusion. Ruminal acetate and propionate concentrations increased linearly with increasing SC+UAS inclusion. In wethers fed diets with a roughage/concentrate ratio of 70:30, roughage constituted of a SC+UAS/hay (Tifton-85) ratio of 41:29 is recommended in order to maximize the DOM intake, N-retention, and MPS.