Consumo e digestibilidade aparente da matéria seca, proteína e energia bruta, e balanço de nitrogênio das silagens de cinco genótipos de milho Consumption and apparent digestibility of dry matter, crude protein and crude energy, and balance of nitrogen of silages of five maize genotypes

Quantificaram-se o consumo voluntário e a digestibilidade aparente da matéria seca, proteína bruta, energia bruta e balanço de nitrogênio das silagens de cinco genótipos de milho (HT01, HT47C, HT129, AG 5011 e BR 3123). Foram utilizados 15 carneiros alojados em gaiolas metabólicas para coleta total de fezes e urina. O delineamento experimental foi o inteiramente ao acaso com cinco tratamentos e seis repetições. Não foram observadas diferenças entre os genótipos quanto ao consumo e digestibilidade da MS, da EB e da PB (P>0,05). Os consumos de MS, EB e PB digestíveis e energia metabolizável também não foram diferentes entre os híbridos (P>0,05). Quanto às relações consumo de energia digestível/consumo de MS e consumo de energia metabolizável/consumo de MS, o genótipo AG5011 foi semelhante ao HT01 (P>0,05) e superior aos demais (P<0,05). Todos os tratamentos apresentaram balanço de nitrogênio positivo e não diferiram entre si (P>0,05). Todos os genótipos produziram silagens de bom valor nutritivo, entretanto o genótipo AG5011 apresentou maior eficiência na utilização da energia (P<0,05).<br>The voluntary intake and the apparent digestibility of dry matter, crude protein and crude energy and the nitrogen balance, of silages of five maize genotypes (HT01, HT47C, HT129, AG5011 and BR3123) were quantified. Fifteen sheep were stored in metabolic cages for total collection of feces and urine. A complete randomized design, with five treatments and six repetitions was used. The intake and digestibility of dry matter, crude protein and crude energy did not differ (P>0.05) among treatments. The intake of digestible dry matter, crude protein, crude energy and metabolic energy did not differ (P>0.05) among the genotypes. The ratios of digestible energy intake/dry matter intake and metabolic energy intake/dry matter intake of the genotype AG5011 silage was similar (P>0.05) to HT01, and higher than the other genotypes (P<0.05). All genotypes showed similar and positive nitrogen balance, and all of them produced silages of good nutritional value. Nevertheless, silage of AG5011 genotype showed higher efficiency of energy (P<0.05) utilization

Digestibility and microbial efficiency in steers fed diets based on corn silage hybrids and concentrate levels

A trial involving a 2x2 factorial design was conducted to evaluate the effect of corn silage hybrids and concentrate levels (25 and 50%) on intake and digestibility of nutrients, ruminal characteristics and microbial efficiency in steers. Four ruminal and abomasal cannulated steers (512±25kg of birth weight), were used in a 4×4 Latin square design. Treatments consisted of 75% silage A + 25% concentrate; 50% silage A + 50% concentrate; 75% silage B + 25% concentrate; and 50% silage B + 50% concentrate on dry matter (DM) basis. There were no differences in the intakes of DM, organic matter (OM), crude protein, and ether extract. The intake of non fiber carbohydrates and total digestible nutrients were positively affected by concentrate levels. The digestibility of DM and OM were also positively affected by concentrate levels. There were no effects of treatments on ruminal pH values, ruminal ammonia-N, and microbial efficiency

Intake and total apparent digestibility in lambs fed six maize varieties in the Brazilian Semiarid

The objective of this study was to evaluate the daily intake and total apparent digestibility of dry matter, organic matter, crude protein, gross energy, ether extract, neutral detergent fiber, acid detergent fiber, total and non-fibrous carbohydrates, total digestible nutrients, energy intake and nitrogen balance of silages of six maize varieties with early or super early cycles recommended to Northeast Brazil. Twenty-four male castrated lambs were lodged in metabolic cages. A completely randomized design with six treatments and four replications was used, with means compared by Tukey test at 5%. There were no differences among varieties for any of the evaluated variables regarding intake and apparent digestibility. Concerning the intake of digestible energy, metabolizable energy and the ratio content of digestible and metabolizable energy, significant differences were observed between varieties and BRS Assum Preto showed highest values of metabolizable energy (2.650,8 kcal/day). All of the treatments presented positive nitrogen balance and did not differ among themselves. The varieties asessed can be an additional option to the semiarid regions in Brazil