| Autor: |
Souza RTA; Department of Animal Science, Federal Rural University of Pernambuco, Dom Manoel de Medeiro Street, Dois Irmãos, Recife, Pernambuco 52171-900, Brazil., Dos Santos MVF; Department of Animal Science, Federal Rural University of Pernambuco, Dom Manoel de Medeiro Street, Dois Irmãos, Recife, Pernambuco 52171-900, Brazil., Cunha MVD; Department of Animal Science, Federal Rural University of Pernambuco, Dom Manoel de Medeiro Street, Dois Irmãos, Recife, Pernambuco 52171-900, Brazil., Gonçalves GD; Federal University of Agreste of Pernambuco, Bom Pastor Avenue, Boa Vista, Garanhuns, Pernambuco 55292-270, Brazil., Silva VJD; Department of Animal Science, Federal Rural University of Pernambuco, Dom Manoel de Medeiro Street, Dois Irmãos, Recife, Pernambuco 52171-900, Brazil., Mello ACL; Department of Animal Science, Federal Rural University of Pernambuco, Dom Manoel de Medeiro Street, Dois Irmãos, Recife, Pernambuco 52171-900, Brazil., Muir JP; Texas A&M AgriLife Research, 1229 Hwy 281, Stephenville, TX 76401, USA., Ribeiro REP; Department of Animal Science, Federal Rural University of Pernambuco, Dom Manoel de Medeiro Street, Dois Irmãos, Recife, Pernambuco 52171-900, Brazil., Dubeux JCB Jr; North Florida Research and Education Center, University of Florida, 3925 Hwy 71, Marianna, FL 32446-8091, USA. |
| Abstrakt: |
This two-year study evaluated the effect of Pennisetum purpureum genotypes under rainfed or irrigated conditions, during the dry and rainy seasons, on herbage, leaf, and stem dry matter (DM) accumulation rates, nutritive value, and carbohydrate and protein fractionation. Treatments were tall (Iri 381 and Elefante B) or dwarf (Mott and Taiwan A-146 2.37) genotypes under rainfed or irrigated conditions. Taiwan A-146 2.37 (146 kg DM ha per day) showed similar herbage accumulation rate (HAR) to tall genotypes during the rainy season (124 and 150 kg DM/ha per day, respectively). Dwarf genotypes showed differences in leaf accumulation rate (LAR) (66 and 49 kg DM/ha per day). Mott leaf had less neutral detergent fiber (NDF) (589 g/kg DM) than Taiwan A-146 2.37 (598 g/kg DM), and tall genotypes had generally greater NDF (668 g/kg DM) than the dwarf genotypes. Irrigation increased fiber deposition in the leaf. Stems of all genotypes had lower in vitro digestible dry matter (IVDDM) (378 g/kg DM) under rainfed conditions in the rainy season. Leaf from irrigated plots had 23% more carbohydrate C fraction (160 g/kg CHO) than those from rainfed plots (122 g/kg CHO). Dwarf genotypes had generally greater nutritive value than tall genotypes. These genotypes show promise under irrigation to fill forage gaps during dry periods. |
