Changes in Soil Fertility and Plant Nutrient Contents in Degraded Tropical Pasture After Renovation

A grazing experiment was conducted on an Oxisol testing five degraded tropical grasses renovated with two levels of fertilizer with the objective to study seasonal changes in plant nutrient contents and soil fertility. Total dry matter availability, green and dead matter availabilities, nutrient concentration in leaf tissue and soil fertility were the parameters measured. Availability of forage and leaf nutrients was significantly dependent on seasonal changes with green matter on offer decreasing over years. Soil fertility increased after renovation and declined thereafter. Soil available-P decreased and it was related to sustainability of green matter on offer. Soil organic matter mineralization was the greater N source to plants. Lack of regular N supply plus soil-P decline would be responsible for decreasing of stocking rate and animal production

Beef Cattle Production on Renovated Grass Pastures in Savannas of Brazil

A 3-year grazing trial was conducted, to study animal production on degraded grass pastures, renovated by two levels of fertilization. All paddocks were divided into halves: one received 1.5 t/ha of dolomitic limestone, 400 kg/ha of a fertilizer formula 0-16-18 and 50 kg/ha of microelements (FL1); and the other 3.0 t/ha , 800 kg/ha and 50 kg/ ha of the same fertilizers (FL2). Productivity on FL2 pastures was greater than that on FL1 pastures, averaging 565 and 395 kg of liveweight gain (LWG)/ha/year, respectively. For all grasses the productivity in both fertilizer treatments decreased linearly from the first to the third, from means of 670 and 435 to means of 445 and 325 kg/ha/year, for FL2 and FL1, respectively. Progressive reduction in forage availabilities led to significant reduction of stocking rates over time and consequent productivity. Obviously, balanced nutrition with Ca, P, K, but mainly N, is required to sustain productivity of grass pastures

Avaliação da carcaça de cabritos Saanen alimentados com dietas com grãos de oleaginosas

Foram utilizados 16 cabritos Saanen não castrados dos 15,16±1,60kg até 30,61±0,33kg de peso vivo, distribuídos em delineamento inteiramente ao acaso, alimentados com dietas (tratamentos) com grãos de linhaça, girassol ou canola. A dieta-controle foi formulada com feno de aveia, farelo de soja, milho moído e suplemento vitamínico-mineral. Os pesos da carcaça quente e fria e os rendimentos da carcaça e de cortes comerciais não foram modificados pelos tratamentos. A dieta com grãos de canola resultou em maior perda por resfriamento da carcaça e menor proporção de gordura no lombo, e a proporção de osso no lombo foi maior para os animais que receberam linhaça ou canola. Os teores de umidade, proteína, lipídios totais e cinzas do músculo Longissimus dorsi não foram alterados com a adição dos grãos de oleaginosas. A dieta com grãos de linhaça resultou em aumento do teor de ômega-3 no músculo, e o teor de colesterol e a razão ômega-6/ômega-3 foram menores nos tratamentos que continham linhaça, girassol e canola. A inclusão dos grãos de oleaginosas nas dietas não alterou as características quantitativas da carcaça de cabritos Saanen, mas melhorou a qualidade da carne, que apresentou menos colesterol e mais ômega-3, com o uso de linhaça