The present study aimed to evaluate two rotational stocking intervals (GI) over three consecutive grazing periods on forage productivity, crude protein and neutral detergent fibre of Urochloa brizantha cv. Marandu pastures, and the subsequent impact on milk production. Grazing treatments were (1) fixed rest period at 30 days (30-FG) and (2) grazing interval when canopy was intercepting 95% photosynthetically active radiation (95-LI). Eighteen multiparous Holstein × Zebu cows (548 ± 61.0 kg bodyweight, BW) and 70 ± 18.1 days in milk were used. Experiment lasted for 99 days (i.e. 33 days per period). Nine cows with similar milk production and BW were randomly allocated to each GI treatment balanced on milk production and BW. The adjustment of carrying capacity per paddock was made aiming to achieve a post-grazing residual height of 20 cm. For this, additional dry Holstein × Zebu cows (averaging 550 kg BW) were added and removed from the paddocks according put-and-take technique. Data were statistically analysed considering field sites as block (n = 2), GI (30-FG vs 95-LI), periods (three consecutive) and interaction GI × periods. Interactions occurred between GI and periods for pre- and post-grazing height (P ≤ 0.05). Greater pre-grazing height was observed for 30-FG (P < 0.01), but post-grazing height was greater (P < 0.01) for 30-FG only in the third period. GI for treatment 30-FG was ~6 days longer (P = 0.01) than that for 95-LIand light interception was greater (2%) for 30-FG. Total forage, stem and dead material mass per area were greater (P < 0.01) for 30-FG than 95-LI. However, stocking rate was 11.3% greater (P = 0.02) for 95-LI than 30-FG. In the pre-grazing period, 95-LI had greater (P < 0.01) proportion of leaves and a greater leaf : stem ratio, whereas neutral detergent fibre concentration tended to be lower (P = 0.08) and crude protein concentration greater (P < 0.01) in 95-LI than in 30-FG. Daily milk productivity per area and its components were 16–28% greater (P < 0.01) for 95-LI than for 30-FD. These results suggest that GI of Marandu grass determined by light interception at 95% (95-LI) enabled the reduction of GI, improved forage nutritive value and increased milk productivity compared with a fixed 30 days (30-FG) of rest.

RESUMOAvaliou-se a qualidade das silagens de três híbridos de sorgo, BRS 610, BR 700 e BRS 655, colhidos em três estádios de maturação da planta, grãos leitoso, pastoso e farináceo. O delineamento utilizado foi o inteiramente ao acaso, em esquema fatorial 3x3 (híbridos x estádios de maturação), com quatro repetições. Os teores de matéria seca apresentaram variação de 22,9% a 41,3%. O BR 700 apresentou maior porcentagem de matéria seca que os demais híbridos em todas as idades de corte. Os teores de proteína bruta e as frações fibrosas, fibra em detergente neutro e fibra em detergente ácido, apresentaram comportamento diferente entre estádios de maturação e entre híbridos. Os valores de lignina não foram alterados com o avanço da idade de corte. Os coeficientes de digestibilidade in vitro da matéria seca das silagens variaram de 50,7% a 55,6% e comportaram-se de forma diferente com a maturidade para cada hibrido. De acordo com os valores de pH, de nitrogênio amoniacal e de ácidos orgânicos encontrados, as silagens dos três híbridos são classificadas como de boa qualidade em todos os períodos de colheita. Palavras-chave: Sorghum bicolor (L.) Moench, momento de colheita, valor nutritivo ABSTRACT

No abstract

No abstract

Enzyme additives have been added to forage at ensiling to improve nutritive value. The aim of this study was to evaluate effects of adding exogenous enzymes to silage on fermentative losses and profile, aerobic stability, chemical composition, in vitro degradation, microbial quality, and nutrients intake and digestibility. Treatments were control (CON); addition of exo-1,4-α-glycosidase glucoamylase (GLU; Kerazyme 3035, Kera Nutrição Animal, Bento Gonçalves, Brazil); addition of β-glucan 4-glucanhydrolase (CEL); and GLU + CEL. Data from the silo experiment were analyzed using PROC MIXED of SAS, with fixed effects of glucoamylase and cellulase, and interaction effect between them. In vivo experiment analyses also included fixed effect of Latin Square and period, and random effect of animal within Latin Square. CEL increased (P ≤ 0.038) gas losses and effluents production, CEL and GLU decreased (P = 0.039) DM recovery compared to control but not differ from GLU+CEL. CEL silage had higher (P ≤ 0.021) starch and crude protein and in vitro digestibility of DM and NDF (P ≤ 0.032), while GLU had higher (P = 0.001) ADF. CEL showed lower (P = 0.012) ethanol content and higher (P = 0.02) anaerobic bacteria counts, while GLU showed higher (P = 0.012) lactate concentration and lower (P ≤ 0.002) counts of bacteria and fungi. Lambs fed with CEL presented higher (P ≤ 0.012) digestibility coefficients for DM, OM, CP and NDF. Decrease on DM recovery indicates no improvements on the nutritive value of silage. On the other hand, cellulolytic enzyme positively affected animal digestion.

This study aimed to evaluate total mixed ration silages with sugarcane and the additives microbial inoculant and chitosan. Thirty mini-silos were used in a completely randomized design, with three treatments and ten replications. Silages were composed of sugarcane mixed with corn bran, whole soybean, urea, and mineral mixtures at a 50:50 roughage to concentrate ratio. Treatments consisted of control silage, microbial additive (Lactobacillus plantarum + Pediococcus acidilactici, 4 g/t of KeraSil, Kera Nutrição Animal), and chitosan (10 g/kg of natural matter). Silages were evaluated for fermentation and microbiological profile, fermentation losses, aerobic stability, chemical-bromatological composition, intake, and digestibility. Fermentation profile showed no significant difference between treatments for pH values, with a mean value of 4.79. Production of acetic and propionic acids showed no difference between treatments, with mean values of 7.34 and 0.053 mmol/kg DM, respectively. Dry matter, organic matter, and crude protein intake of the total mixed ration silage differed statistically from the other treatments (P<0.05), but fresh sugarcane and sugarcane silage intake did not differ from each other (P>0.05). Digestibility values of DM, OM, and NDF were higher in the total mixed ration silage (P<0.05), while sugarcane silage and fresh sugarcane showed no difference from each other (P>0.05). Total mixed ration silage increased nutrient intake and digestibility, with a better fermentation pattern when added with the microbial inoculant.