Valor nutritivo da cana-de-açúcar adicionada com óxido de cálcio para novilhas Holandês x Zebu

Foram avaliados os consumos e as digestibilidades aparentes da matéria seca (MS), matéria orgânica, proteína bruta e os consumos da matéria seca digestível e dos nutrientes digestíveis totais (NDT), em 18 novilhas Holandês x Zebu, distribuídas em blocos ao acaso, alimentadas com cana-de-açúcar acrescida ou não a 1% de óxido de cálcio - na matéria natural - após 24 horas de hidrólise, com diferentes tempos de administração da mistura de ureia e sulfato de amônio - zero e 24 horas antes do fornecimento aos animais. As diferenças entre as médias foram avaliadas por contrastes ortogonais, a 1% de significância. Houve efeito negativo (P&lt;0,01) da adição do óxido de cálcio no consumo de NDT, na digestibilidade aparente da matéria orgânica e na eficiência da utilização do nitrogênio. A administração de ureia no momento da hidrólise causou diminuição no consumo e na digestibilidade aparente da PB. Não houve benefício tanto da inclusão de óxido de cálcio quanto da adição de ureia 24 horas antes do fornecimento aos animais.</jats:p

In vitro dry matter and cell wall fractions of three genotypes of sunflower ensiled with additives

Ensilaram-se três genótipos de girassol (M734, Rumbosol 91 e variedade V2000), enriquecidos no material original com: 0,5% de uréia (U); 0,5% de carbonato de cálcio (CC); 0,5% de uréia mais 0,5% de carbonato de cálcio (U+CC); inoculante bacteriano comercial (IB) comercial e sem aditivo que serviu como silagem testemunha (T). Foram utilizados silos de laboratório de PVC, abertos com 1, 3, 5, 7, 14, 28 e 56 dias de ensilados, sendo determinados fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), lignina e digestibilidade in vitro da matéria seca (DIVMS). As silagens de Rumbosol 91 apresentaram valores superiores aos dos genótipos V2000 e M734 nos dias de abertura para FDN, FDA e lignina. Os aditivos não promoveram alterações nos constituintes da parede celular. A silagem T não apresentou diferenças entre os genótipos quanto à DIVMS no decorrer do processo fermentativo, sendo os valores do último dia de abertura (56) de 51,0%, 49,1% e 48,9% de DIVMS para os genótipos M734, V2000 e Rumbosol 91, respectivamente. Não houve diferença entre as silagens com aditivos e a silagem testemunha com a evolução do processo fermentativo quanto à DIVMS. Os aditivos utilizados não melhoraram as silagens de girassol quanto às características avaliadas e, apesar de os genótipos apresentarem digestibilidade in vitro semelhantes, o Rumbosol 91 apresentou maiores teores de constituintes da parede celular.Three sunflower genotypes (M 734, Rumbosol 91 and V2000 variety) enriched with 0.5% of urea (U); 0.5% of calcium carbonate (CC); 0.5% of urea plus 0.5% of calcium carbonate (U + CC); commercial bacterial inoculate (BI); and without any additive, used as control silage (T) were ensiled in PVC silos and opened after 1, 3, 5, 7, 14, 28 and 56 days to determine the neutral detergent fiber (NDF), acid detergent fiber (FDA), lignin and dry matter in vitro digestibility (DMIVD). The Rumbosol 91 genotype silage showed higher NDF, ADF and lignin than V2000 and M734 genotypes. The additives did not promote changes in the cell wall constituents. No statistical differences among silages of the genotypes for DMIVD were observed during the fermentative process. The DMIVD at 56 days were 51.0, 49.1 and 48.9% for silage of M734, V2000 and Rumbosol 91 genotypes, respectively. No difference between silages with additives and control (T), during the fermentative process for DMIVD was observed. The additives did not improve sunflower silages. The genotypes showed similar in vitro digestibility, and the Rumbosol 91 genotype showed high compound of cell wall constituent

Energy and protein requirements of 3/4 Zebu × 1/4 Holstein crossbreds fed different calcium and phosphorus levels in the diet

The aim of this study was to determine the nutritional requirements of energy and protein for maintenance and weight gain of crossbred cattle, as well as their efficiencies. Fifty 3/4 Zebu × 1/4 Holstein crossbred bulls with initial weights of 214±4kg and aged 11±0.2 months on average were used in this experiment. Four animals were used in the reference group; ten bulls were fed at the maintenance level; and the remaining 36 bulls were fed ad libitum and distributed in a completely randomized design in a 3×3 factorial arrangement, which had three feedlot periods (56, 112 or 168 days) and three calcium and phosphorus levels (low, medium and normal) in the diet. Four of the maintenance animals had their heat production measured by respirometry at the Laboratory of Metabolism and Calorimetry of UFMG. After slaughter, composite samples, referred to as carcass and noncarcass samples were obtained from each animal. The net energy requirements for maintenance (NEm) and metabolizable energy for maintenance (MEm) were 68.9 and 90.1 kcal/EBW0.75/day, respectively. The efficiency (km) was 76.41%. The NEm requirement determined in the respirometry chamber was 85.5 kcal/kg0.75. The following equations were obtained for net energy for gain (NEg) and net protein for gain (NPg): NEg (Mcal/day) = 0.0505±0.000986 × EBW0.75 × EBWG1.095 and NPg (g/day) = 162.79±18.2546 × EBWG - 1.30±5.3010 × RE. The efficiencies of fat and protein deposition were 70.04 and 15.12%, respectively. In conclusion, the requirements of NEm for growing and finishing non-castrated 3/4 Zebu × 1/4 Holstein crossbred cattle are 68.9 kcal/EBW0.75/day. Requirements of NEg and NPg can be obtained by the following equations: NEg (Mcal/day) = 0.05050.000986 × EBW0.75 × EBWG1.095 and NPg (g/day) = 162.79±18.2546 × EBWG - 1.30±5.3010 × RE