SUMMARY The present study aiming to determine the nutritional quality of oat (Avena sativa L.) IPR 126 in order to produce forage for ruminants. Four periods between harvests were used: 14, 21, 28 and 35 days, distributed in randomized blocks with four replicates for each treatment. The variables evaluated were: the concentration of dry matter (DM), neutral detergent insoluble fiber (NDF), crude potein (CP), lignin, dry matter (DM), ash, ether extract (EE) and in vitro digestibility of dry matter obtained by measurement of gas production. The profile of gas production was adjusted to the logistic bicompartimental mathematical model. The variables and the parameters of the adjusted gas production curves were analyzed as repeated measurements through the PROC MIXED of SAS (version 9.0) and the restricted maximum likelihood (REML) as the method of estimation of parameters. Regression analysis was performed for the variables: DM, CP, EE, NDF, ash, and for the parameter k2 of the bicompartimental model. DM and NDF concentrations increased linearly, CP, ash, and the estimations of the parameter k2 reduced linearly and the EE concentration showed a cubic behavior in function of the age of harvest. Lignin and other parameters of the Schofield model were not influenced by the age of harvest. The harvest interval influenced some chemical components and degradation rate of fiber carbohydrates, but do not interfere in lignin concentration. The forage with 21 days of cutting interval has the high nutritional value.

The aim was to evaluate the productive quality and fermentative as like the nutritional parameters of winter grass silage in the vegetative and reproductive stages in two consecutive crop years. The experiment was carried out at Universidade Tecnológica Federal do Paraná, Campus Dois Vizinhos, Brazil, from April 2012 to December 2013. The experimental field had a 560 m2 area; it comprised 32 plots of 16 m2 each, with a space of 0.5 m between blocks. Four winter grass species were used, including Avena sativa L. ‘IPR 126’ (white oat), Avena strigosa Schreb. ‘IAPAR 61’ (lopsided oat), Lolium multiflorum Lam. ‘Barjumbo’ (ryegrass), and Secale cereale L. ‘Temprano’ (rye), being evaluated through silage making in two phenological stages, vegetative and reproductive. The experimental design was randomized block in a bifactorial scheme (cultivar and phenological phase of pasture). The experimental materials were ensiled in polyvinyl chloride (PVC) microsiles, with four replicates per treatment. Pre-drying and ensiling allowed the preservation of material quality. The highest yields of dry matter per hectare were obtained in the reproductive stage; however, the nutritive content at this stage was relatively lower when compared with vegetative. The rye presented relatively less variation of the nutritional composition between the studied phenological stages. The ash content of the forage influenced the pH of the silage, and the highest pH was verified at the vegetative stage. Even with pre-dehydration, the vegetative stage presented a greater loss of effluents than the reproductive stage.

89Composição química e cinética de degradação ruminal da aveia branca (Avena sativa L.) cv. IPR126 sob diferentes níveis de nitrogênioChemical composition and ruminal degradability of white oat ("Avena sativa" L.) cv. IPR126 under different nitrogen levels

Our objective was to identify the best fit mathematical models for in vitro gas production kinetics using rumen fluid and forage plants commonly used in ruminant feed to obtain better estimates of parameters that describe the rumen fermentation. Four mathematical models were tested, two unicompartmental (M1 = first order, M2 = Gompertz) and two bicompartmental (M3 = M1 + M2; M4 = M2 + M2). Two temperate grasses were evaluated, as well as four tropical grasses and three temperate forage legumes. The fit of the models was verified by the corrected Akaike information criterion (AICc r ) and the difference among AICc r values (Δ r ), likelihood probability (W r ), and relative likelihood (ER r ). Temperate forages reached maximum gas production between 48 and 72 h. In the tropical forages, it occurred only after 72 h. In profiles in which M3 was the best choice, the values of parameters V f 1 were higher than those of V f 2 , and k 1 values were higher than k 2 values. The only exception was for Tifton 85 profile, whose V f 2 value was higher than V f 1 . The model M3 has a better fit for tropical forages with higher fiber content and lower levels of nonfibrous carbohydrates and crude protein. The model M1 has a better fit for forage with higher nonfibrous carbohydrate contents and low lignin content.

Sugar cane is highly productive (dry matter.hectare-1), but after ensiling process nutritional quality is affected, thus additives are needed to control or minimize losses. This study aimed to evaluate if Lactobacillus plantarum LPBR01 strain used as silage inoculant for sugar cane can control fermentation losses. Sugar cane samples (72) were divided in two treatments with three replicates, control (no Lactobacillus) and treatment silage with Lactobacillus (106 CFU g-1 of silage). Nutritional composition of samples in different periods of fermentation (0, 7, 15, 30 and 45 days) was estimated by determining levels of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HEM), mineral matter (MM) and acid detergent lignin (ADL). Fermentative profile of the silage was characterized by determining sugars, ammoniacal nitrogen, acidity and pH at 0, 12, 24, 36, 48, 60 and 72 hours. Inoculation of sugar cane silage with Lactobacillus plantarum LPBR01 strain presented no significant results (p ≤ 0, 5) however, interaction between treatment and day (p ≤ 0, 5) could be observed for the levels of ADF. The Lactobacillus plantarum LPBR01 strain was not efficient to control the fermentation losses that occur in the silages of sugar cane at the concentration used in this study.