Efeitos dos sistemas de pastejo isolado, simultâneo e alternado de ovinos com bovinos sobre as características da forragem, desempenho, consumo e características de carcaça dos ovinos

Abstract

A presente dissertação apresenta uma pesquisa-ação que buscou construir uma práxis educacional ao ar livre em uma escola classe pública, localizada no Distrito Federal. A autora atuou como educadora e pesquisadora em um processo de ecoformação no ano de 2008, no qual se abordou a Educação Ambiental a partir da agroecologia e da permacultura. A partir de vivências e reflexões propiciadas pelas oficinas ecopedagógicas realizadas nos jardins da escola, a comunidade escolar inseriu a Educação Ambiental no Projeto Político Pedagógico. Criaram-se então mecanismos de promoção, acompanhamento e avaliação da prática do Projeto Político Pedagógico. O processo de observação e compreensão da prática docente ocorreu enfatizando as atividades desenvolvidas entre 2008- 2009, permeadas pelas rodas de conversa realizadas com os professores, a observação da percepção dos estudantes no momento de atuação no espaço verde e da entrevista realizada com a coordenadora pedagógica. Os resultados alcançados foram interpretados em uma narrativa descritiva com abordagem etnometodológica de todo processo e das práticas educativas realizadas na área verde da escola. Inovações no projeto político pedagógico da escola, o surgimento de uma comunidade de aprendizagem que discute e reflete sobre o uso da área verde como espaço pedagógico e o exercício de uma pedagogia ativa e significativa são os elementos que encontramos como resultado da experiência vivida. _________________________________________________________________________________________ ABSTRACT

The aim of this study was to evaluate the effects of three types of rotational pasture: isolated (I); simultaneous (S); and alternated (A) with sheep and cattle on structural and chemical traits of grass, voluntary dry matter intake, animal performance and carcass traits of sheep. The experimental period lasted 99 days. A experimental area of Panicum maximum cv. Tanzânia was used, with rotational pasture. There were 2 AU/ha. Twelve crossbred heifers, weighing initially 207 kg and 30 Santa Inês lambs weighing 23 kg were used as well as 16 adult ewes weighing 47 to standardize grazing pressure. The sheep received 200 g/animal/day of concentrate and cattle 2 kg/animal/day. The following parameters were determined on the pasture: forage mass available per grazing cycle (FMC); proportion of leaf (PL); stalk (PS); dead material (PDM), ratio leaf:stalk (L/S); levels of dry matter (DM), mineral (MM); crude protein (CP); ether extract (EE); neutral detergent fibre (NDF); acid detergent fibre (ADF); inorganic phosphorus (Pi) and total digestible nutrients (TDN). Animal weights included: weekly (WW); initial (WI) and final (WF), as well as weight gains: live weight (LWG) and mean daily weight gain (MDW). Dry matter intake was estimated 84 days after the start of the experiment using external indicators LIPE® - Purified and Enriched Lignin, to obtain total dry matter intake (DMItotal); from pasture (DMIpasture); in crude protein (DMIPB); per kg live weight (DMI%PV), metabolic weight (MW) and dry matter intake per kg metabolic weight (DMIMW). Carcass traits were measured including slaughter weight (SW), hot carcass (HCW) and cold carcass (CCW); hot carcass killout (HCK) and cold carcass (CCK); loss due to cooling (LCooling); fat cover (FC); skin weight (SkinW) and xii thickness (ST); thoracic (TOW) and abdominal (AOW) organ weight; scrotal (EC) and leg (LC) circumference; external carcass length (ECL); half carcass weight as well as weights and percentages of leg, shoulder, neck, back and ribs. The 12th rib was used to evaluate weight, eye muscle area (EMA); weight and percentages of muscle, bone and fat, levels of humidity, dry matter, protein, ether extract, mineral matter and edible portion as well as ratios muscle:bone and muscle:fat. The worst of all types of rotational pasture for traits of grass was A with results of PL, L/S, CP, NDF, ADF and TDN equivalents a 51,62, 1,90, 12,05, 70,34, 39,22 and 49,81%, respectively. There was no difference by S and I for grass traits. The worst of animal performance was to A, with 11,5 kg of LWG and 0,122 kg of MDW. Carcass traits were not affected by pasture system. The S system may be an alternative to traditional sheep rearing systems in the Brazilian savannah region.