This study evaluated the effect of different seeding rates and cutting heights on production and composition of millet. Two randomized block design experiments were performed. In the first trial, 32 parcels (1.2 × 1.2 m) were used for evaluation of seeding rate of 24, 35, 50 and 60 kg/ha. Three cuts were carried out to evaluate plant height, fresh and dry mass yield, dry matter (DM), neutral detergent fiber (NDF), crude protein (CP) and acid detergent lignin (ADL) concentration and in situ DM and NDF digestibility. In the second trial, 20 parcels (1.2 × 3.0 m) were used to evaluate 20, 30, 40 and 50 cm of cutting heights for two growing cycles, performing the evaluations previously listed. Seeding rate linearly increased plant height, fresh and dry mass production, and tended to linearly decrease dry matter in situ digestibility, without effects on forage composition. Cutting height had no effect on crude protein (CP) concentration, but linearly increased plant height, dry mass production, DM content and tended to decrease NDF in situ digestibility and ADL content. Thus, the use of the highest evaluated seeding rates (60 kg/ha) and cutting height (50 cm) increased forage production; however, the use of the lowest residual height increased forage quality.

Common protein sources used in the manufacturing of diets for dogs are derived from by-products, which may have reduced digestibility depending on the source. This study evaluated the effect of the addition of a protease, the papain enzyme, as a supplement to extruded diets on palatability, nutrient digestibility, and fecal production and quality of dogs. A diet was formulated with poultry by-product meal, meat and bone meal, and feather meal as protein sources. This formula was divided into three isonutrient diets: one negative control (NC), without enzymes; treatment one (EZ1) with addition of 855.000UI of papain per kilogram of diet, and treatment two (EZ2) with addition of 2.280.000UI of papain per kilogram of diet, both added before extrusion. The experiment followed a randomized block design, with two blocks of nine animals (three animals per treatment in each block), 18 dogs in total, and six replicates per treatment. Data were submitted to analysis of variance and the means of three treatments were compared by polynomial contrasts (P <0.05). No differences in the coefficients of total tract apparent digestibility of nutrients nor changes in palatability, pH, and fecal production among treatments were found with the addition of different doses of enzyme to the diets (P > 0.05). The fecal score was reduced with increased addition of enzyme (P < 0.05).

The aim of the present study was to evaluate the effect of two crude protein contents (CP) and two main nitrogen sources in the diet of dairy cows, using sugarcane as forage, on intake, total apparent digestibility, milk yield and composition, and nitrogen balance. Twelve Holstein cows in late lactation were assigned in three contemporary square, in a Latin Square design 4 × 4, with 2 × 2 factorial treatment arrangement, in 21-day trial by period, 14 for diet adaptation and the last seven for sampling and analysis. Cows were housed in individual stalls and fed a total mixed ration (TMR) "ad libitum" composed of two main nitrogen sources (cottonseed meal or whole raw soybean grain) and two levels of CP (130g or 148g/kg dry matter - DM) in the diet. In the present study, there was an interaction effect between nitrogen source and crude protein on DM intake (DMI). Cows fed whole raw soybean had higher DMI when the CP content of the diet was 130 g CP/kg DM, while cows fed cottonseed meal had higher DMI when the CP content of the diet was 148 g CP/kg DM. A similar result of DMI was observed for organic matter intake, whereas there was no interaction effect between dietary nitrogen source and crude protein content on intake of other nutrients. Total apparent digestibility of NDF and TDN was higher when soybean was used as the main diet nitrogen source; whereas the digestibility of dietary CP was not changed by the nitrogen sources. Although there were changes in the DMI and the apparent digestibility coefficient, in the current study, there was no effect of dietary crude protein content and nitrogen source on milk yield. In conclusion, the use of low dietetic concentrations of crude protein (130 g/Kg of DM) does not change the lactating performance of dairy cows and may reduce diet cost, while the choice between whole raw soybean grain or cottonseed meal as a protein ingredient may depends only on the availability and/or price, as both ingredients result in similar performance.

Two experiments were conducted to evaluate the effect of the level and degradability of crude protein (CP) on the digestive metabolism and productive performance of dairy cows. In both experiments, 15 Holstein cows with 585 ± 40 kg of body weight were distributed in a Latin square design with five contemporary squares, three periods of 21 days and three treatments. In experiment 1, treatments consisted of three CP levels (130, 160 or 180 g CP/kg DM), while in experiment 2, the treatments consisted of three levels of rumen degradable protein (RDP; 80, 100 or 120 g RDP/kg DM) in diets with average of 163 g CP/kg DM. Variables evaluated in both experiments were dry matter intake (DMI), total apparent digestibility, milk yield (MY) and composition, ruminal fermentation and N balance. In experiment 1, the increase of CP from 130 to 180 linearly increased the organic matter, CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF) intake (kg) and the apparent total digestibility coefficient of DM and CP. In addition, a linear increase of MY, fat corrected milk (FCM) and daily production of fat, protein, lactose, casein and total solids was observed. A linear increase in ruminal ammoniacal nitrogen (NH3-N) concentration and nitrogen excretion in milk, feces and urine was also observed. However, there was no observed effect on SCFA concentration. In experiment 2, the increase of the RDP from 80 to 120 increased the DMI, MY, FCM, milk protein content and digestibility coefficient of the NDF, ADF and ethereal extract. Additionally, there was an increase in NH3-N concentration and milk nitrogen excretion. The studies indicated that the increase of CP content up to 100 g RDP/kg DM increased the DMI and the productive performance of the cows, but also increased urine N. Thus, it is desirable that the increase of the CP through the increase of the RDP is carried out up to 100 g of RDP/kg DM, since there is elimination of nitrogen, decrease of milk yield and decrease of propionic acid in values above that level.