Effects of corn and sorghum rehydrated and ensiled on performance and carcass characteristics of young Nellore bulls

O presente trabalho foi dividido em dois capítulos, onde objetivou-se avaliar o consumo, a digestibilidade, o desempenho e as características de carcaça de bovinos Nelore superprecoces (Capítulo 1) e estimar as exigências nutricionais de energia e proteína destes animais (Capítulo 2). Foram utilizados 34 bovinos Nelore não castrados, com peso médio inicial de 270±21 kg e idade média de 7 meses. Seis animais foram selecionados aleatoriamente para compor o grupo referência, sendo abatidos ao início do experimento para determinação do peso de corpo vazio (PCVZ) inicial e quatro animais foram designados ao grupo mantença alimentados com 12g MS/kg de peso corporal (PC). Os demais animais foram distribuídos em delineamento inteiramente casualizado em esquema fatorial 2x2, com dois tipos de grãos (milho e sorgo) e dois tipos de processamento (moído seco ou ensilado após a reidratação): Milho moído seco (MMS), sorgo moído seco (SMS), silagem de milho moído reidratado (SMR) e silagem de sorgo moído reidratado (SSR).Todas as dietas continham 28,44% de silagem de milho, 60,83% de cada um dos grãos e 10,73% de um suplemento proteico mineral. Foram realizados três ensaios de digestibilidade nos períodos inicial, médio e final. Os animais foram mantidos em baias coletivas contendo comedouros e bebedouros eletrônicos e abatidos após 140 dias de experimento. Os dados foram submetidos à análise de variância no PROC-MIXED do SAS Software. Em todas as comparações, utilizou-se 5% como nível crítico de probabilidade para ocorrência do erro tipo I. Os resultados obtidos mostraram que o consumo de nutrientes digestíveis totais (CNDT) não foi influenciado pelo tipo de grão ou processamento (P > 0,05). Não houve diferença (P > 0,05) entre os tipos de grãos, com relação aos consumos de matéria seca e demais constituintes, exceto para o consumo de extrato etéreo (CEE). Foi observada influência do tipo de processamento sobre todos os parâmetros de consumo, sendo esses menores para os grãos reidratados (P 0,05) pelo processamento. Foi observada interação entre tipo de grão e processamento (P 0,05) dos tipos de grãos e processamento sobre os parâmetros de desempenho produtivo e características de carcaça. Contudo, a eficiência alimentar foi menor (P 0.05). There was no difference (P > 0.05) among the types of grain, in relation to the consumption of dry matter and other constituents, except for the consumption of ethereal extract (EEC). It was observed the influence of the type of processing on all the parameters of consumption, being smaller for the rehydrated grains (P 0.05) by processing. Interaction between grain type and processing (P 0.05) of the types of grain and processing on the parameters of productive performance and characteristics of carcass. However, the food efficiency was lower (P < 0.05) for the animals that received the diets containing sorghum in relation to maize, and for the diets containing the dried grains in relation to rehydrated ones. Like this the silage of maize grains and rehydrated sorghum reduces the consumption of dry matter and most constituents and increases their digestibility, except for protein. The performance and the carcass characteristics are not affected by rehydration, however the animals fed with the grains after rehydration showed greater food efficiency. For the determination of the nutritional requirements of energy and protein the left half carcass of the slaughtered animals was used. The chemical composition of the empty body was estimated from the section between 9 th and 11 th ribs (Section HH) by the equations validated by Costa and Silva et al. (2013) For Nelore bovine animals: PB (%): PB PCVZ = 10.78 + 0.47 × PBCor -0.21 × SGS and Ethereal extract (%): EE PCVZ = 2.75 + 0.33 × EECor + 1.80 × Gv. Net protein requirements for maintenance were estimated using the following equation: CPM = β0 + β1 × GPCVZ, where CPM = metabolizable protein intake and GPCVZ = empty body weight gain. The net requirement of protein for gain was obtained using the BR-cut equation (2016): PLg = β1 × GPCVZ – β2 × Er. The net energy requirement for maintenance was calculated according to the equation PC = β 0 × and β1 × CEM , being PC = heat production, while the Metabolizable Energy (in) for maintenance was calculated by the iterative process, when one hundred matched the PC. The liquid energy for gain was obtained by the equation ELg = Β0 × PCVZeq 0.75 × GPCVZ β1 . The linear models used were adjusted by means of the SAS proc REG and for non-linear models was used the proc NLIN of the The latter are adjusted by the Gauss- Newton method. To verify the significance of the models was used 5% with critical probability level for occurrence of type I error. The net and metabolizable energy requirements for maintenance of bovine Nelore non- castrated males are 72.7 and 106.55 kcal/PCVZ 0.75 /day, respectively. The net and metabolizable energy requirements for maintenance of bovine Nelore non- castrated males are 72.8 and 106.79 kcal/PCVZ 0.75 /day, respectively. The energy requirements liquid for gain can be obtained by the equation: ELg = 0.0512 × PCVZ 0.75 × GPCVZ 0.9457 . Metabolizable energy use efficiencies for maintenance and for gain in this animal category are 68.2% and 43.6%, respectively. The protein requirements Metabolizable for maintenance of this animal category is 3.48 g/PC 0.75 . The liquid protein requirements for weight gain can be obtained through the equation PLg = 221.669 × GPCVZ – 21.933 × ER.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Reconstituted and ensiled corn or sorghum grain: Impacts on dietary nitrogen fractions, intake, and digestion sites in young Nellore bulls.

Two experiments were conducted: (1) to evaluate the effect of ensiling time and grain source on dietary nitrogen fractions; and (2) to verify the influence of concentrate level, processing method and grain source on intake, microbial efficiency, and digestibility by young Nellore bulls. In Experiment 1, corn and sorghum grains were milled, reconstituted to 35% moisture, and ensiled in a bag silo for 10 different times. There were three replications per ensiling time and grain source. Samples from each replication were analyzed in triplicate for total nitrogen (N), non-protein nitrogen (NPN), soluble N, insoluble N, and neutral detergent insoluble nitrogen (NDIN). In Experiment 2, five Nellore bulls were used in a 5 × 5 Latin square design. Four diets were comprised of 28.4% corn silage, 10.7% supplement, and 60.9% dry ground corn, dry ground sorghum, reconstituted and ensiled corn, or reconstituted and ensiled ground sorghum. An additional diet comprised of 45% corn silage, 10.7% supplement, and 44.3% dry ground corn (Roughage+) was used. Each experimental period lasted 22 days, with an adaptation period of 14 days followed by 5 days of total feces and urine collection and 3 days of collecting omasal samples. Data were analyzed using the MIXED procedure of SAS 9.4. The reconstitution and ensiling process reduced (P 0.05) DM intake nor rumen pH. On the other hand, bulls fed diets based on 72% concentrate showed greater (P < 0.05) DM, OM, and CP digestibility compared with those fed a diet based on 55% concentrate. In addition, animals fed diets based on corn grains (both reconstituted and ensiled or dry) presented greater (P < 0.05) intestinal and total starch digestion compared to those fed sorghum grain. Therefore, the reconstitution process can reduce the insoluble N fraction and increase nutrient availability

Exigências de energia e proteína de bovinos castrados mestiços Holandês x Zebu alimentados com diferentes níveis de cálcio e fósforo na dieta

The aim of this study was to determine the energy and protein requirements of crossbred Holstein x Zebu steers fed with or without the supplementation of dicalcium phosphate in the diet. Thirty-two steers with an average initial body weight of 377.5 ± 49.4 kg were used, of which four were initially slaughtered to estimate the empty body weight (EBW) of the animals. Twenty-four steers were fed ad libitum and were distributed in a completely randomized design with two levels of concentrate (30 and 60 %), and diets with or without dicalcium phosphate and four steers were fed at maintenance level, so that the body weight gain was equal to zero. After 84 days the animals were slaughtered. The animal tissues were sampled, and composted by two samples, denominated by “carcass” (bone, muscle and fat) and “non-carcass” (head, limbs, blood, hide, organs and viscera) for determination of the body composition. The net energy requirements (NEm) and metabolizable energy for maintenance (MEm) were obtained while relating heat production (HP) and metabolizable energy intake (MEI); meanwhile, the net energy requirements for gain (NEg) and the net protein requirements for gain (NPg) were obtained as a function of empty body weight (EBW), empty body gain (EBG) and retained energy (RE) in EBW. The daily net and metabolizable energy requirements for maintenance were 76.90 and 119.36 kcal/EBW0.75, respectively. The net energy requirements for gain can be obtained by the following equation: NEg = 0.0568±0.0025 × EBW0.75 × EBG1.095. The efficiencies of use of metabolizable energy for maintenance and gain are 64.4 and 29.68 %, respectively. The metabolizable protein requirements for maintenance are 4.14 g/BW0.75. The net protein requirements for gain can be obtained through the following equation: NPg = 236.36±30.06 × EBG - 19.84±6.14 × RE. We recommend the use of the equations obtained in this experiment to calculate the energy and protein requirements of crossbred Holstein x Zebu steers.Objetivou-se determinar as exigências nutricionais de energia e proteína para bovinos castrados mestiços Holandês x Zebu alimentados com ou sem suplementação inorgânica de cálcio e fósforo na dieta. Foram utilizados 32 animais mestiços Holandês × Zebu, machos, castrados, com peso corporal (BW) médio inicial de 377,5 ± 49,4 kg, dos quais quatro foram abatidos inicialmente para estimar o peso de corpo vazio (EBW) dos demais, 24 alimentados ad libitum distribuídos em delineamento inteiramente casualizado com dois níveis de concentrado (30 e 60%) e dietas contendo ou não fosfato bicálcico; e quatro alimentados ao nível de mantença, isto é, para que o ganho de peso corporal fosse igual a zero. Após 84 dias os animais foram abatidos. Para determinação da composição corporal dos animais, foram constituídas duas amostras por animal, denominadas “carcaça” (óssos, musculo e gordura) e “não carcaça” (cabeça, membros, sangue, couro, orgãos e visceras). As exigências de energia líquida (NEm) e metabolizável para mantença (MEm) foram obtidas relacionando a produção de calor (HP) e o consumo de energia metabolizável (MEI), enquanto as exigências de energia líquidas para ganho de peso (NEg) e as exigências líquidas de proteína para ganho (NPg) foram obtidas em função do EBW, do ganho de peso de corpo vazio (EBG), e da energia retida (RE) no EBW. As exigências diárias de energia líquida e metabolizável para mantença de bovinos mestiços Holandês × Zebu castrados foram de 76,90 e 119,36 kcal/EBW0,75, respectivamente. As exigências de energia líquida para ganho podem ser obtidas pela equação: NEg = 0,0568±0,0025 × EBW0,75 × EBG1,095. As eficiências de uso da energia metabolizável para mantença e para ganho foram de 64,4 e 29,68%, respectivamente. As exigências de proteína metabolizável para mantença foram de 4,14 g/BW0,75. As exigências líquidas de proteína para ganho de peso podem ser obtidas através da equação NPg = 236,36±30,06 × EBG - 19,84±6,14 × RE. Recomenda-se o uso das equações obtidas nesse experimento para cálculo das exigências nutricionais de energia e proteína para novilhos cruzados Holandês × Zebu castrados

Energy and protein requirements of crossbred Holstein x Zebu steers fed different levels of calcium and phosphorus in the diet

The aim of this study was to determine the energy and protein requirements of crossbred Holstein x Zebu steers fed with or without the supplementation of dicalcium phosphate in the diet. Thirty-two steers with an average initial body weight of 377.5 ± 49.4 kg were used, of which four were initially slaughtered to estimate the empty body weight (EBW) of the animals. Twenty-four steers were fed ad libitum and were distributed in a completely randomized design with two levels of concentrate (30 and 60 %), and diets with or without dicalcium phosphate and four steers were fed at maintenance level, so that the body weight gain was equal to zero. After 84 days the animals were slaughtered. The animal tissues were sampled, and composted by two samples, denominated by “carcass” (bone, muscle and fat) and “non-carcass” (head, limbs, blood, hide, organs and viscera) for determination of the body composition. The net energy requirements (NEm) and metabolizable energy for maintenance (MEm) were obtained while relating heat production (HP) and metabolizable energy intake (MEI); meanwhile, the net energy requirements for gain (NEg) and the net protein requirements for gain (NPg) were obtained as a function of empty body weight (EBW), empty body gain (EBG) and retained energy (RE) in EBW. The daily net and metabolizable energy requirements for maintenance were 76.90 and 119.36 kcal/EBW 0.75 , respectively. The net energy requirements for gain can be obtained by the following equation: NEg = 0.0568 ±0.0025 × EBW 0.75 × EBG 1.095 . The efficiencies of use of metabolizable energy for maintenance and gain are 64.4 and 29.68 %, respectively. The metabolizable protein requirements for maintenance are 4.14 g/BW 0.75 . The net protein requirements for gain can be obtained through the following equation: NPg = 236.36 ±30.06 × EBG - 19.84 ±6.14 × RE. We recommend the use of the equations obtained in this experiment to calculate the energy and protein requirements of crossbred Holstein x Zebu steers.Objetivou-se determinar as exigências nutricionais de energia e proteína para bovinos castrados mestiços Holandês x Zebu alimentados com ou sem suplementação inorgânica de cálcio e fósforo na dieta. Foram utilizados 32 animais mestiços Holandês × Zebu, machos, castrados, com peso corporal (BW) médio inicial de 377,5 ± 49,4 kg, dos quais quatro foram abatidos inicialmente para estimar o peso de corpo vazio (EBW) dos demais, 24 alimentados ad libitum distribuídos em delineamento inteiramente casualizado com dois níveis de concentrado (30 e 60%) e dietas contendo ou não fosfato bicálcico; e quatro alimentados ao nível de mantença, isto é, para que o ganho de peso corporal fosse igual a zero. Após 84 dias os animais foram abatidos. Para determinação da composição corporal dos animais, foram constituídas duas amostras por animal, denominadas “carcaça” (óssos, musculo e gordura) e “não carcaça” (cabeça, membros, sangue, couro, orgãos e visceras). As exigências de energia líquida (NEm) e metabolizável para mantença (MEm) foram obtidas relacionando a produção de calor (HP) e o consumo de energia metabolizável (MEI), enquanto as exigências de energia líquidas para ganho de peso (NEg) e as exigências líquidas de proteína para ganho (NPg) foram obtidas em função do EBW, do ganho de peso de corpo vazio (EBG), e da energia retida (RE) no EBW. As exigências diárias de energia líquida e metabolizável para mantença de bovinos mestiços Holandês × Zebu castrados foram de 76,90 e 119,36 kcal/EBW 0,75 , respectivamente. As exigências de energia líquida para ganho podem ser obtidas pela equação: NEg = 0,0568 ±0,0025 × EBW 0,75 × EBG 1,095 . As eficiências de uso da energia metabolizável para mantença e para ganho foram de 64,4 e 29,68%, respectivamente. As exigências de proteína metabolizável para mantença foram de 4,14 g/BW 0,75 . As exigências líquidas de proteína para ganho de peso podem ser obtidas através da equação NPg = 236,36 ±30,06 × EBG - 19,84 ±6,14 × RE. Recomenda-se o uso das equações obtidas nesse experimento para cálculo das exigências nutricionais de energia e proteína para novilhos cruzados Holandês × Zebu castrados