Produção de forragem de maniçoba espontânea e sua utilização com palma forrageira e jurema preta na alimentação de ovinos.

Abstract

Two randomized block experiments were carried out. In the first one, height and basal diameter of 40 spontaneous maniçoba (Manihot glaziovii) plants in Itapetim-PE were measured in two years, and data on forage production and bromatology were collected from 30 pruned plants, according to 4 pruning levels (0, 33, 50 and 100%) of branches and respective sprouts. Height increase from March 2010 to March 2011 was negatively affected (P<0.05) by pruning level, averaging 0.29, 0.11, 0.43 and -0.04 m/plant, respectively for 0, 33, 50 and 100% pruning. Diameter increase was not affected (P>0.05), but mean increments showed to be higher in smaller than in taller plants for all pruning levels: 6.38 vs 1.56 mm/trunk. Interaction between Pruning level x Type of pruned material (branches or sprouts) had a significant (P<0.05) effect on forage production, as averages were similar in the first (branches) and second (sprouts) collection for 33 (0.66 or 0.75 kg of DM from branches or respective sprouts of each plant) and 50% (1.40 or 1.73 kg of DM, respectively) pruning levels, and decreased in the 100% pruning level (3.37 or 2.06 kg, respectively). Contents of NDF and ADF were greater (P<0.05) in sprouts from plants which were subjected to100% pruning treatment: 62.20 and 46.63%, respectively; contents of CP (from 8.72 to 10.08%) and EE (from 2.74 to 4.35%) were not affected (P>0.05) by pruning levels and type of material. Ash content was higher (P<0.05) in sprouts, and reached 5.9%. In the second experiment, carried out at UFCG/CSTR facilities in Patos-PB, the performance of 24 lambs (12 Santa Inês and 12 Dorper lambs) was estimated for 3 levels (0, 17 and 33%) of spineless cactus (SC) inclusion in the diet as a substitute of a balanced brand mixture of elephant grass (Pennisetum purpureum), jurema preta (Mimosa tenuiflora) and maniçoba. Mean daily live body weight gain (DLBWG) of lambs was significantly affected by spineless cactus inclusion, and showed a maximum value for Santa Inês (115 g/animal) and Dorper (112 g/animal) lambs for 17 or 33% inclusion of SC, respectively. Daily dry matter consumption was affected (P<0.05), and averages were 738.74, 861.03 and 766,56 g/Santa Inês lambs, and 611.13, 715.56 and 759.11 g/Dorper lambs, respectively for 0, 17 and 33% SC inclusion. Food conversion was significantly affected by the inclusion and was similar in both lamb breeds (P>0.05), and decreased (P<0.05) from above 14, at 0% SC inclusion, to values between 4.94 and 6.24, when SC was included in the diet. Daily water consumption (DWC) decreased (P<0.05) 2/5 with SC inclusion. Santa Inês lambs decreased DWC from 1034.96 to 591.16 g/animal, respectively for 0 and 33% SC inclusion. For the Dorper lambs, the respective values were 1132.03 and 706.27 g/animal. Spontaneous maniçoba plants can furnish more than 1 kg of DM forage/plant by the annual collection of 50% of its fine branches and respective sprouts. This forage and that collected from jurema preta can compose 38 and 31% of the diet and result in estimated DLBWGs of 121 and 113 g for Santa Inês and Dorper lambs, respectively.