ABSTRACT. Productive performance for silage production of five forage sorghum genotypes (BRS Ponta Negra, BRS 655, BR 601, BRS 506 and BRS 610) was evaluated through the yield of dry matter, digestible dry matter, and fresh matter, plant height, percentage of lodged and broken plants, and anatomical fractions in Brazilian semi-arid region. BRS 506 and BRS Ponta Negra varieties achieved the highest fresh forage yields (89.4 and 76.2 ton. ha -1 ), and BRS 506, stood out for dry and digestible dry matter yield (25.2 and 12.1 ton. ha -1 , respectively). Regarding the participation of the plant fractions, BRS 655 and BRS 610 genotypes showed a higher percentage of panicles (50.2 and 41.0% respectively), while BRS 506 stressed out the stem participation (84.6%), and BRS Ponta Negra, the leaf participation (17.9%). Among the materials evaluated for silage production, stood out the BRS 506 and BRS Ponta Negra genotypes. The results obtained for production of dry and digestible dry matter, and the ratio of plant fractions indicates the possible use of these genotypes on silage production in the Brazilian semiarid.Keywords: forage, dry matter, nutrition, ruminants, Sorghum bicolor (L.) Moench.Características agronômicas de cultivares de sorgo forrageiro para produção de silagem no Submédio do Vale do São Francisco RESUMO. O objetivo deste trabalho foi avaliar a produtividade de matéria seca, matéria verde e matéria seca digestível, altura das plantas, percentual de plantas acamadas e quebradas e a participação das frações anatômicas da planta de cinco genótipos de sorgo forrageiro para a região semiárida brasileira (BRS Ponta Negra, BRS 655, BR 601, BRS 506 e BRS 610), visando à produção de silagem. As variedades BRS 506 e BRS Ponta Negra apresentaram maiores produtividades de matéria verde (89,4 e 76,2 t ha -1 ). A variedade BRS 506 destacou-se pela produtividade de matéria seca e matéria seca digestível (25,2 e 15,7 t ha -1 , respectivamente). Quanto à participação das frações da planta, os genótipos BRS 655 e BRS 610 apresentaram maior percentual de panícula (50,2 e 41,0%, respectivamente), enquanto a variedade BRS 506 apresentou 84,6% de participação do colmo e a variedade BRS Ponta Negra, 17,9% de participação das folhas. Entre os materiais avaliados para produção de silagem destacaram-se as variedades BRS 506 e BRS Ponta Negra. Os resultados obtidos para produção de matéria seca e matéria seca digestível, assim como a relação das frações da planta atestam a possibilidade de utilização dos genótipos avaliados para a produção de silagem na região semiárida brasileira.Palavras-chave: forragem, matéria seca, nutrição, ruminantes, Sorghum bicolor (L.) Moench.

SUMMARYPearl millet (Pennisetum glaucum (L.) R.) could play an important role as a feed source for ruminants in arid and semi-arid zones of the world owing to its high yield and drought tolerance. The current paper assessed the agronomic characteristics, ensilability, intake and digestibility of five Brazilian pearl millet cultivars (IPA Bulk1BF, BRS 1501, CMS-03, CMS-01 and BN-2) in a typical Brazilian northeastern semi-arid climate. Forage was harvested at the dough stage of grain maturity (growth stage 86 according to the BBCH scale) and ensiled under laboratory and farm conditions. Apparent digestibility of the silages was determined using 25 Santa Inês male lambs. The cultivars CMS-01, CMS-03 and BN-2 out-performed the others in terms of dry matter (DM) and digestible DM yield/ha. At DM partitioning among plant tissues, the cultivar IPA Bulk1BF had a greater DM associated with panicles and one of the greatest concentrations of organic matter, lactic acid and in vitro dry matter digestibility among the five cultivars. The cultivar BRS 1501 had greater butyric acid concentration as well as one of the highest pH values. Silage produced from BN-2 not only contained greater acetic acid concentration, but also showed one of the greatest total volatile fatty acid concentrations. There were no differences in feed intake and digestibility of nutrients and fibre fractions across all cultivars. Silage made from BN-2 resulted in greater urinary excretion of nitrogen than those produced from BRS 1501. Under the conditions of the present study, the results obtained for production of DM and digestible dry matter, and the ratio of plant fractions, indicates the possible use of these cultivars for silage production in the Brazilian semi-arid region.

Forage sorghum (FS) (Sorghum bicolor (L.) Moench) is a key feed source for ruminants owing to its high yield and drought tolerance. The present paper assessed the agronomic characteristics, silage quality, intake and digestibility of five new Brazilian sorghum cultivars (BRS Ponta Negra variety, BRS 655 hybrid, BR 601 hybrid, BRS 506 variety and BRS 610 hybrid). Forages were grown (randomized complete block design) in a typical Brazilian north-eastern semi-arid climate, irrigated with 267 mm water, harvested as plants reached the soft dough stage of grain maturity and ensiled under laboratory and farm conditions. Apparent digestibility of the silages was determined using 25 Santa Inês lambs. BRS 506 outperformed the other cultivars in dry matter (DM) and digestible DM yields/ha. BRS 506 exhibited the lowest neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents and the highest in vitro dry matter digestibility (IVDMD) of the cultivars examined. BRS 655 produced the lowest level of lactic acid and the highest pH and ammonia-N concentration. There was no difference in intake or digestibility of DM among cultivars. Silages produced from BRS Ponta Negra resulted in higher crude protein (CP) intake than BRS 655. Silages made from BRS 506 and BRS Ponta Negra resulted in a greater digestibility of CP than those produced from BRS 655. Intake of NDF in silages generated from BRS Ponta Negra and BRS 610 was higher than that found in other cultivars. Although an average Brazilian North-eastern FS exhibited similar characteristics to other cultivars grown in dry regions around the world, the results indicated that BRS 506 had a yield advantage and higher nutritive value under Brazilian semi-arid conditions as compared to the other cultivars examined.

The aim of this research was to determine (210)Pb concentrations in rocks and soils of farms located in the municipalities of Pedra and Venturosa. In these farms, rolled blocks of mafic rock with a high percentage of U(3)O(8) were found. The concentrations of (210)Pb varied from 3.2 to 201 kBq kg(-1) in rock samples and from 195 to 86,400 Bq kg(-1) in soil samples. The high levels of radioactivity found in the samples, indicate the need to conduct more detailed studies to evaluate the risk of radionuclide ingestion due to milk consumption by the population in the state of Pernambuco.

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