Tamara Tais Tres

Production of tifton 85 hay overseeded with white oats or ryegrass

The objective of this experiment was to estimate the curve of dehydration, chemical composition and in vitro dry matter digestibility (IVDMD) and crude protein digestibility (IVCPD) of tifton 85 hay, produced single or overseeded with ryegrass or white oat IPR 126. The experimental design was in randomized blocks, in a 3 × 10 factorial arrangement, with three cropping systems and ten evaluation times (0, 4, 8, 24, 28, 32, 48, 52 and 56 and 71 hours after harvest) during the dehydration process. For chemical composition and in vitro DM and CP digestibility, the experimental design was in randomized blocks with three cropping systems and three evaluation times (before cutting, before baling and 100 days after of storage). It was found that tifton 85 intercropped with white oat kept its higher nutritional value after storage, with 19.78% crude protein and 70.03% of in vitro dry matter digestibility. The participation of white oat in tifton 85 area was 57.04% and for ryegrass, it was 38.52%, but the dry matter yield of single tifton 85 was higher than other intercrops. Thus, it is recommended an oversowing of winter annual species on Tifton 85, without moisture restriction, because of the benefits obtained in the hay nutritional value.

IPR 126 white oat forage potential under free growth, cutting and grazing at two management heights

The experiment was carried out to evaluate the structural characteristics, biomass accumulation, chemical composition and in vitro digestibility of dry matter and crude protein of white oat (Avena sativa L. IPR 126) under different management systems. Grazing, cut at two heights (15 and 20 cm) and free growth were all evaluated in three periods (July, August and September) with a 28-day average interval between evaluations. In the free growth system, samples at 15 and 20 cm were also taken at the intervals chosen for cutting and grazing. The experimental design was in randomized blocks with three replications, arranged in a 3 × 2 factorial split plot design over time; systems of management and heights were the factors of plots, and time was taken as subplot. There was higher straw production under free growth, but, with decreased chemical quality from the first to the second period and from the second to the third one, with 236.4, 172.5, and 91.4 g/kg crude protein values, respectively. Regarding cutting and grazing systems, they showed structural changes in tillering, which was favored by the cut, but with some reduction in the periods. Nutritional quality values were close to cutting and grazing with high crude protein content (216.6 g/kg), adequate neutral detergent fiber (535.4 g/kg) content and high in vitro digestibility of dry matter (826.3 g/kg). Management heights promoted few changes in the characteristics evaluated. After the third period, cutting and grazing systems showed no suitable residual straw for ground covering and set a summer crop under no-tillage system, with 738.39 kg/ha of residual dry matter on average.

Production technology and quality of corn silage for feeding dairy cattle in Southern Brazil

The objective of this study was to evaluate the production practices and use of corn silage in dairy farms in Southern Brazil, and to evaluate their impact on the nutritional quality and occurrence of mycotoxins. The data were collected by application of questionnaires among the producers, and by analysis of silage samples. The variables were subjected to factorial analysis of data reduction through the principal components method, thus obtaining 84.12% of the variance associated with the location, corn hybrid, crop production management, and inoculant used, characterizing the farms into four distinct groups. In farms from Parana, the silage production technologies were more associated with implantation and crop management processes, and investment in equipment related to ensilage/silo feed-out was less frequent. Farms of Rio Grande do Sul showed high adoption of outsourced services, self-propelled machines, bunker silos, double-sided plastic film, and inoculant to control aerobic deterioration, and the silages showed higher levels of propionic acid (7.95 g/kg DM), and lower concentrations of aflatoxins (7.7 ppb) and total mycotoxins (26.58 ppb). The farms evaluated in Southern Brazil have good production efficiency and corn silages with excellent quality, regardless of their production characteristics.

Use of a conditioning unit at the haymaking of Tifton 85 overseeded with Avena sativa or Lolium multiflorum

White oat and ryegrass were overseeded on Tifton 85 pastures for evaluation of dry matter yield (DMY), leaf:stem ratio (L:S), dehydration curves and nutritional value of forages. Dry matter intake and L:S ratio were analyzed using a completely randomized blocks design with five forage growth conditions (single Tifton 85 and intercropped with white oat or ryegrass, and white oat or ryegrass intercropped with Tifton 85), whereas for drying curves, ten dehydration times were tested (0, 4, 8, 24, 28, 32, 48, 52, 56 and 71 hours after harvest) by a 5 × 10 split-plot arrangement (growth conditions of forages as main plot and dehydration times as sub-plots). The nutritive value data were analyzed in a 3 × 3 split-plot trial with single Tifton 85, Tifton 85 - Oat and Tifton 85-Ryegrass as main plots and the three sampling times (before harvesting, at baling and 100 days after storage) as sub-plots. Oat and ryegrass showed higher L:S ratio, while the intercrops of Tifton 85 - Oat and Tifton 85 - Ryegrass presented lower DMY, but higher crude protein concentration and in vitro DM digestibility than single Tifton. Neutral and acid detergent fiber concentrations were higher for single Tifton 85. Ryegrass and white oat, overseeded on Tifton 85 pasture, improved the nutritional value of the hay produced; however, in a 100-day storage period, there was a reduction in in vitro dry matter digestibility and crude protein concentrations.

Dry matter production, chemical composition, dry matter digestibility and occurrence of fungi in Bermuda grass hay (Cynodon dactylon) under different fertilization systems or associated with pea plantings in winter

J.P. Ames, M.A. Neres, D.D. Castagnara, L.M. Mufatto, C. Ducati, C.C. Jobim, and T.T. Tres. 2014. Dry matter production, chemical composition, dry matter digestibility and occurrence of fungi in Bermuda grass hay (Cynodon dactylon) under different fertilization systems or associated with pea plantings in winter. Cien. Inv. Agr. 41(2): 163-174. This study aimed to evaluate the structural characteristics, dehydration curve, DM production, chemical composition, in vitro dry matter digestibility and occurrence of fungi in Bermuda grass hay (Cynodon dactylon cv. ´Bermuda grass´, Tifton 85) produced in winter under different forms of fertilization or in association with a winter annual legume. The experimental design used was a randomized block with split plots in time and with four treatments: Bermuda grass without fertilization or intercropping, Bermuda grass with nitrogen (N) chemical fertilizer (100 kg N ha 1 year -1 ), Bermuda grass oversown with forage pea (Pisum arvense cv. ´Iapar 83´), and Bermuda

Silagem de grãos de milho, com adição de soja: estabilidade aeróbia e desempenho de vacas leiteiras

Objetivou-se avaliar o efeito do uso de aditivo microbiano e de ureia na composicao quimica, digestibilidade in vitro, no desaparecimento ruminal, e na estabilidade aerobia de silagens de graos umidos de milho com adicao de soja crua. Um segundo ensaio foi conduzido com o objetivo de avaliar a substituicao do concentrado comercial por silagem de graos de milho com adicao de 20% de soja crua na producao e composicao do leite de vacas holandesas. Para a avaliacao das silagens foram feitos mini silos de pvc arranjados em delineamento inteiramente casualizado com tres tratamentos (silagem de graos umidos de milho + 20% de soja crua; silagem de graos umidos de milho + 20% de soja crua + inoculante microbiano e silagem de graos umidos de milho + 20% de soja crua + 1,4% de ureia) e quatro repeticoes. As silagens apresentaram-se estaveis no periodo de 96 horas, com perdas de materia seca de 3,55, 3,32 e 4,39 para silagens sem aditivos, com a adicao de inoculante microbiano e com ureia respectivamente. A adicao de ureia diminuiu a taxa de degradacao ruminal das silagens de graos umidos de milho com adicao de soja. Para a avaliacao da producao e composicao do leite foram utilizadas 20 vacas leiteiras arranjadas em delineamento inteiramente casualizado, com dois tratamentos e dez repeticoes. Verificouse que a silagem de graos de milho com adicao de graos de soja pode ser usada na alimentacao de vacas em lactacao sem impacto sobre a producao e composicao quimica do leite, mantendo os niveis de producao.