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Differences and/or similarities in the influence of sex class for hair sheep requirements remain inconclusive. Knowledge of energy requirements allows well-formulated diets to be provided which is crucial for improving animal production. We aimed to determine the effect of sex class on the net energy requirements of growing hair sheep in a multi-study approach. We used a data set composed of individual measurements of 382 hair sheep (299 non-castrated and 83 castrated males) from 11 studies that used the methodology of comparative slaughter. Net energy requirements for maintenance (NEm) were obtained by the regression between heat production and metabolizable energy intake. The metabolizable energy requirements for maintenance (MEm) were calculated by the iterative method, and the efficiency of use of metabolizable energy for maintenance (km) was obtained by NEm divided by MEm. The net energy requirements for gain (NEg) were estimated from retained energy (RE) against empty BW gain (EBWG). The efficiency of energy use for weight gain (kg) was obtained from the relationship between RE and the energy metabolizable intake for gain, removing the intercept. There was an effect of sex on NEg and two equations were generated: NEg (MJ/day) = 1.040 (±0.04055) × EBW0.75 × EBWG0.8767(±0.03293) and NEg (MJ/day) = 1.040 (±0.04055) × EBW0.75 × EBWG0.8300(±0.03468) (R2 = 0.86; MSE = 0.0037; AIC = -468.0) for non-castrated and castrated males, respectively. Sex class did not affect kg (P > 0.05) and one kg was generated (0.29). Sex did not affect kprotein (P = 0.14) and kfat (P = 0.32), assuming an average deposition efficiency of 0.27 for protein and 0.78 for fat. The NEm and MEm did not differ (P > 0.05) between sex classes, with a value of 0.272 and 0.427 MJ/kg0.75 EBW per day, respectively. The km observed was 0.64. In conclusion, non-castrated and castrated male hair sheep have similar maintenance energy requirements although energy requirements for gain differed among them. The Committees overestimate the gain and maintenance requirements for hair sheep. Therefore, the equations generated in this study are recommended.

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This study determined the energy requirement for maintenance of purebred Nellore cattle and its crossbreds using data from a comparative slaughter trial in which animals were raised under the same plane of nutrition from birth through slaughter and born from a single commercial Nellore cowherd. A total of 79 castrated steers (361 ± 54 kg initial body weight [BW]) were used in a completely randomized design by age (22 mo ± 23 d of age) with four genetic groups (GG): Nellore (NL), ½ Angus × ½ Nellore (AN), ½ Canchim × ½ Nellore (CN), and ½ Simmental × ½ Nellore (SN). The experimental design provided ranges in metabolizable energy (ME) intake (MEI), BW, and average daily gain needed to develop regression equations to predict net energy for maintenance (NEm) requirements. Four steers of each GG were slaughtered to determine the initial body composition. The remaining 63 steers were assigned to different nutritional treatments (NT) by GG; ad libitum or limit-fed treatments (receiving 70% of the daily feed of the ad libitum treatment of the same GG). Full BW was recorded at birth, weaning, 12, 18, and 22 mo. In the feedlot, steers were fed for 101 d a diet containing (DM basis) 60% corn silage and 40% concentrate. No difference in age at weaning (P = 0.534) and slaughter (P = 0.179 and P = 0.896, for GG and NT, respectively) were observed. AN steers were heavier at weaning weight, yearling weight and had higher empty BW (EBW; P = 0.007, P = 0.014, and P < 0.001, respectively) in comparison to NL, CN, and SN. There were no interactions (P > 0.05) between GG and NT for any variable evaluated. When fed ad libitum, AN steers had higher daily MEI (Mcal/d; P < 0.001) in comparison to NL, CN, and SN. On a constant age basis, differences were observed on body composition (P < 0.05) between GG. The slope (P = 0.600) and intercept (P = 0.702) of the regression of log heat production on MEI were similar among GG. Evaluating at the same age and the same frame size, there were no differences in NEm requirement between Nellore and AN (P = 0.528), CN (P = 0.671), and SN (P = 0.706). The combined data indicated a NEm requirement of 86.8 kcal/d/kg0.75 EBW and a ME required for maintenance requirement had a common value of 137.53 kcal/d/kg0.75 EBW. The efficiency of energy utilization for maintenance and the efficiency of energy utilization for growth values were similar among GG (P > 0.05 and P > 0.05, respectively) and were on average 63.2% and 26.0%, respectively. However, although not statistically different, the NEm values from NL showed a decrease in NEm of 5.76% compared with AN steers.

Although several studies have shown that the maintenance energy expenditures vary with breeds, there has been no available data comparing the energy requirements of different genetic groups of beef cattle determined during the finishing phase when raised under the same plane of nutrition from birth through slaughter born from a single cowherd. This study evaluated the influence of purebred Nellore and its crosses with Simmental, Angus, and Canchim slaughtered at the same age and body composition on their net energy requirement for maintenance (NEm). Animals were reared in tropical conditions, receiving only free-choice minerals from birth through the beginning of the feedlot phase, potentially altering the intake, carcass composition, mature weight, and consequently, affecting the energy requirement for maintenance during the finishing period. The pooled data analysis for Nellore and its crosses resulted in common NEm requirement of 86.9 kcal/d/kg0.75 of empty body weight (EBW). However, although not statistically different, the NEm values from Nellore (NL) and Angus × Nellore (AN) were 85.5 and 90.8 kcal/d/kg0.75 EBW, respectively, showing a decrease in NEm of 5.76% for NL in comparison with AN steers.

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The tomato leaf miner, Tuta absoluta (Meyrick), is the most important pest for tomato production in Iran. The effect of flubendiamide and thiocyclam hydrogen oxalate insecticides was assessed on cellular energy allocation (CEA) of the third instar larvae of T. absoluta ingesting six different tomato cultivars. Plant leaves were treated with LC50 concentration of both insecticides and their energy available (Ea), energy consumption (Ec), and CEA were calculated. The results showed that total energy reserves (protein, carbohydrate, and lipid budgets) were significantly reduced after exposure to insecticides and tomato secondary metabolites. The larvae fed on Riogrande and Super Chief cultivars showed the least amount of energy available after treatment with both insecticides. The highest rate of oxygen consumption was observed in larvae fed on Calj, Super Luna, and Super strain B after treatment with flubendiamide. The amount of CEA decreased in treated larvae compared to untreated larvae. This reduction was statistically higher in treated larvae that fed on Riogrande and Super strain B cultivars. Reduction in CEA is probably due to the expenses of dealing with detoxification of insecticides and plant metabolites. CEA is a suitable and primary biomarker for the effects of cultivars and insecticides as integrate and summarizes insect energy allocation in variable situations.

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ABSTRACT This study assessed whether the net energy (NE) system is beneficial for determining the efficiency of feed utilization in Chinese Yellow Chickens. A total of 5,600 male Chinese Yellow Chickens were assigned to eight dietary treatments (ten replicate pens per treatment and 70 chickens per pen) of differing apparent metabolizable energy (AME) and NE values. A highly significant linear correlation between dietary energy and feed conversion ratios (FCR) was observed (p 0.01). The linear regression equation between metabolizable energy (ME) and FCR was: AME=1435.5×F/G+6278.2, where R²=0.8272. The linear regression equation between NE and FCR was NE=1350.1×F/G+5340.9, and R²=0.9551. The R² of FCR (0.9551) for diets formulated using NE values was higher than the R² of FCR (0.8272) for diets prepared on the basis of the ME system. We conclude that the NE system is more accurate than the AME system for determining the energy requirements of Chinese Yellow Chickens.

RESUMEN

The objective of this study was to evaluate sequential metabolizable energy (ME) plans, maintaining the lysine: calorie ratio for piglets from 7 to 30 kg. Forty eight female piglets with initial weight of 6.9 ± 1.2 kg and final weight of 30.5 ± 3.8 kg were randomly allocated in a randomized complete blocks design to three nutritional plans with eight replicates and two animals per experimental unit. Sequential plans provided four ME levels: plan 1: 3,300-3,250-3,200-3,150 kcal ME kg-1, plan 2: 3,400-3,350-3,300-3,250 kcal ME kg-1, and plan 3: 3,500-3,450-3,400-3,350 kcal ME kg-1 of feed, from 7 to 10 kg, 10 to 15 kg, 15 to 20 kg and 20 to 30 kg, respectively. From 7 to 10 kg, there was no effect (P>0.05) of the nutritional plans in the evaluated variables. From 7 to 15 kg, a higher (P 0.05) energy intake and weight gain and a better (P 0.05) feed conversion was observed in animals fed with nutritional plans 2 and 3. Nutritional plans 2 and 3 resulted in higher (P 0.05) final weight, feed intake, energy intake, digestible lysine intake, weight gain, and better feed conversion in the 7 to 20 kg, 7 to 25 kg and 7 to 30 kg. It is recommended the sequential plan containing 3,400-3,350-3,300-3,250 kcal ME kg-1 of feed from 7 to 10 kg, from 10 to 15 kg, 15 to 20 kg, and from 20 to 30 kg; respectively, equivalent to levels of 2,546-2,513-2,501-2,475 kcal net energy (NE) kg-1 of feed for piglets.(AU)

Realizou-se este estudo com o objetivo de avaliar planos sequenciais de energia metabolizável (EM), mantendo a relação lisina: caloria, para leitões dos 7 ao 30 kg. Foram utilizados 48 leitões, fêmeas, com peso inicial de 6,9 ± 1,2 kg e final de 30,5 ± 3,8 kg, distribuídos em delineamento de blocos ao acaso em três planos nutricionais, sendo: 1- 3.300-3.250-3.200-3.150 Kcal de EM kg-1 de ração; 2- 3.400-3.350-3.300-3.250 Kcal de EM kg-1 de ração; e 3- 3.500-3.450-3.400-3.350 Kcal de EM kg-1 de ração, dos 7 aos 10 kg, dos 10 aos 15 kg, dos 15 aos 20 kg e dos 20 aos 30 kg, respectivamente, com oito repetições e dois animais por unidade experimental. Dos 7 aos 10 kg, não houve efeito (P>0,05) dos planos nutricionais nas variáveis avaliadas. Observou-se, dos 7 aos 15 kg, maiores (P 0,05) consumos de energia e ganho de peso e melhor (P 0,05) conversão alimentar nos animais alimentados com os planos nutricionais 2 e 3. Os leitões alimentados com os planos nutricionais 2 e 3 apresentaram maior (P 0,05) peso final, consumos de ração, de energia, de lisina digestível, ganho de peso e melhor conversão alimentar nos períodos dos 7 aos 20 kg, dos 7 aos 25 kg e dos 7 aos 30 kg. Recomenda-se o plano sequencial contendo 3.400-3.350-3.300-3.250 Kcal de EM kg-1 de ração dos 7 aos 10 kg, dos 10 aos 15 kg, 15 aos 20 kg e dos 20 aos 30 kg, respectivamente, equivalentes aos níveis de 2.546-2.513-2.501-2.475 Kcal de energia líquida kg-1 de ração.(AU)

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ABSTRACT: The objective of this study was to evaluate sequential metabolizable energy (ME) plans, maintaining the lysine: calorie ratio for piglets from 7 to 30 kg. Forty eight female piglets with initial weight of 6.9 ± 1.2 kg and final weight of 30.5 ± 3.8 kg were randomly allocated in a randomized complete blocks design to three nutritional plans with eight replicates and two animals per experimental unit. Sequential plans provided four ME levels: plan 1: 3,300-3,250-3,200-3,150 kcal ME kg-1, plan 2: 3,400-3,350-3,300-3,250 kcal ME kg-1, and plan 3: 3,500-3,450-3,400-3,350 kcal ME kg-1 of feed, from 7 to 10 kg, 10 to 15 kg, 15 to 20 kg and 20 to 30 kg, respectively. From 7 to 10 kg, there was no effect (P>0.05) of the nutritional plans in the evaluated variables. From 7 to 15 kg, a higher (P<0.05) energy intake and weight gain and a better (P < 0.05) feed conversion was observed in animals fed with nutritional plans 2 and 3. Nutritional plans 2 and 3 resulted in higher (P<0.05) final weight, feed intake, energy intake, digestible lysine intake, weight gain, and better feed conversion in the 7 to 20 kg, 7 to 25 kg and 7 to 30 kg. It is recommended the sequential plan containing 3,400-3,350-3,300-3,250 kcal ME kg-1 of feed from 7 to 10 kg, from 10 to 15 kg, 15 to 20 kg, and from 20 to 30 kg; respectively, equivalent to levels of 2,546-2,513-2,501-2,475 kcal net energy (NE) kg-1 of feed for piglets.

RESUMO: Realizou-se este estudo com o objetivo de avaliar planos sequenciais de energia metabolizável (EM), mantendo a relação lisina: caloria, para leitões dos 7 ao 30 kg. Foram utilizados 48 leitões, fêmeas, com peso inicial de 6,9 ± 1,2 kg e final de 30,5 ± 3,8 kg, distribuídos em delineamento de blocos ao acaso em três planos nutricionais, sendo: 1- 3.300-3.250-3.200-3.150 Kcal de EM kg-1 de ração; 2- 3.400-3.350-3.300-3.250 Kcal de EM kg-1 de ração; e 3- 3.500-3.450-3.400-3.350 Kcal de EM kg-1 de ração, dos 7 aos 10 kg, dos 10 aos 15 kg, dos 15 aos 20 kg e dos 20 aos 30 kg, respectivamente, com oito repetições e dois animais por unidade experimental. Dos 7 aos 10 kg, não houve efeito (P>0,05) dos planos nutricionais nas variáveis avaliadas. Observou-se, dos 7 aos 15 kg, maiores (P<0,05) consumos de energia e ganho de peso e melhor (P < 0,05) conversão alimentar nos animais alimentados com os planos nutricionais 2 e 3. Os leitões alimentados com os planos nutricionais 2 e 3 apresentaram maior (P<0,05) peso final, consumos de ração, de energia, de lisina digestível, ganho de peso e melhor conversão alimentar nos períodos dos 7 aos 20 kg, dos 7 aos 25 kg e dos 7 aos 30 kg. Recomenda-se o plano sequencial contendo 3.400-3.350-3.300-3.250 Kcal de EM kg-1 de ração dos 7 aos 10 kg, dos 10 aos 15 kg, 15 aos 20 kg e dos 20 aos 30 kg, respectivamente, equivalentes aos níveis de 2.546-2.513-2.501-2.475 Kcal de energia líquida kg-1 de ração.

RESUMEN

The development of beef calves born of Charolais (CH), Nellore (N), and Charolais × Nellore crossbred cows with Charolais (CHP) and Nellore (NP) predominance, was evaluated from birth to 12 months of age. The cows were grouped into three age classes: primiparous, young and adult. The net energy requirements for maintenance and gain of the calves were also evaluated, as were the production and availability of energy in the milk of the evaluated cows. We used 93 pairs of contemporary cows and calves maintained in natural pasture. From birth to 21 days of age and from 21 to 42 days of age, the calves of adult cows presented the highest average daily weight gain (ADG), while the calves of young and primiparous cows had similar ADG. The highest net energy requirements for maintenance (NEm) and gain (NEg) were for crossbred and Charolais calves, the latter being similar to Nellore calves. The energy available in the milk of the adult cows was 33% higher than that of primiparous cows. The weight gain of calves was influenced by the age of the cow until weaning. The pre-weaning and post-weaning weights of calves were affected by the genetic group, and adult and young cows produced heavier calves in the pre-weaning period than primiparous cows.

Avaliou-se o desenvolvimento de bezerros de corte, do nascimento aos 12 meses de idade, filhos de vacas Charolês (CH), Nelore (N) e mestiças com predominância Charolês e Nelore (PCH, PN), respectivamente, agrupadas em três classes de idade: primíparas, jovens e adultas. Adicionalmente, foram avaliadas as exigências de energia líquida de mantença e de ganho dos bezerros, bem como a produção e a disponibilidade de energia no leite das vacas avaliadas. Foram utilizados 93 pares de vacas e bezerros contemporâneos mantidos em pastagem natural. Do nascimento aos 21 dias de idade, e dos 21 aos 42 dias de idade, os bezerros filhos de vacas adultas apresentaram maior ganho de peso médio diário (GMD), já os bezerros filhos das vacas jovens e primíparas obtiveram GMD similar. A maior exigência de ELm e ELg foram para os bezerros cruzados e puros Charolês, sendo estes últimos semelhantes aos bezerros Nelore. A energia disponível no leite das vacas adultas foi 33% superior à energia disponível no leite das vacas primíparas. O ganho de peso dos bezerros foi influenciado pela idade da vaca até o desmame. Os pesos pré e pós-desmama dos bezerros são afetados pelo grupo genético das vacas. Vacas adultas e jovens produzem bezerros mais pesados no período pré-desmama do que vacas primíparas.

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The development of beef calves born of Charolais (CH), Nellore (N), and Charolais × Nellore crossbred cows with Charolais (CHP) and Nellore (NP) predominance, was evaluated from birth to 12 months of age. The cows were grouped into three age classes: primiparous, young and adult. The net energy requirements for maintenance and gain of the calves were also evaluated, as were the production and availability of energy in the milk of the evaluated cows. We used 93 pairs of contemporary cows and calves maintained in natural pasture. From birth to 21 days of age and from 21 to 42 days of age, the calves of adult cows presented the highest average daily weight gain (ADG), while the calves of young and primiparous cows had similar ADG. The highest net energy requirements for maintenance (NEm) and gain (NEg) were for crossbred and Charolais calves, the latter being similar to Nellore calves. The energy available in the milk of the adult cows was 33% higher than that of primiparous cows. The weight gain of calves was influenced by the age of the cow until weaning. The pre-weaning and post-weaning weights of calves were affected by the genetic group, and adult and young cows produced heavier calves in the pre-weaning period than primiparous cows.(AU)

Avaliou-se o desenvolvimento de bezerros de corte, do nascimento aos 12 meses de idade, filhos de vacas Charolês (CH), Nelore (N) e mestiças com predominância Charolês e Nelore (PCH, PN), respectivamente, agrupadas em três classes de idade: primíparas, jovens e adultas. Adicionalmente, foram avaliadas as exigências de energia líquida de mantença e de ganho dos bezerros, bem como a produção e a disponibilidade de energia no leite das vacas avaliadas. Foram utilizados 93 pares de vacas e bezerros contemporâneos mantidos em pastagem natural. Do nascimento aos 21 dias de idade, e dos 21 aos 42 dias de idade, os bezerros filhos de vacas adultas apresentaram maior ganho de peso médio diário (GMD), já os bezerros filhos das vacas jovens e primíparas obtiveram GMD similar. A maior exigência de ELm e ELg foram para os bezerros cruzados e puros Charolês, sendo estes últimos semelhantes aos bezerros Nelore. A energia disponível no leite das vacas adultas foi 33% superior à energia disponível no leite das vacas primíparas. O ganho de peso dos bezerros foi influenciado pela idade da vaca até o desmame. Os pesos pré e pós-desmama dos bezerros são afetados pelo grupo genético das vacas. Vacas adultas e jovens produzem bezerros mais pesados no período pré-desmama do que vacas primíparas.(AU)

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An experiment was conducted to compare the effects of increasing dietary net energy (NE) in finishing pig diets while either maintaining a standardized ileal digestible lysine:NE ratio (SID Lys:NE) or maintaining SID Lys as a constant percentage of the diet across increasing energy densities. A total of 150 pigs (Line 600 × 241; DNA, Columbus, NE; initially 35.7 kg) were used in a 91-d study. Pigs were blocked by sex and weight and randomly assigned to 1 of 5 treatments with 2 pigs per pen and 15 pens per treatment. Treatments included a low-energy control diet that was corn-soybean meal-based with added soybean hulls, and a 2 × 2 factorial arrangement of treatments with main effects of increasing dietary NE (medium or high by adding choice white grease) and formulation method (with a SID Lys:NE ratio or maintaining the same percentage SID Lys). Linear and quadratic contrasts were made using the control diet and the medium- and high-energy diets within each formulation method. Pigs and feeders were weighed approximately every 30 d to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). At the end of the experiment, pigs were sent to a commercial processing facility for carcass data collection. From days 0 to 34 and 34 to 61, ADG and SID Lys intake increased as NE increased (linear, P < 0.05) in pigs fed diets with a Lys:NE ratio, but not for those fed the same percentage Lys. As NE increased, NE intake and G:F increased (P < 0.01) in pigs fed diets with either formulation method. From days 61 to 91, increasing NE had no effect (P > 0.10) on ADG. There was no change in G:F in pigs fed diets with the same percentage Lys (P > 0.10), but G:F decreased then increased (quadratic, P < 0.01) in response to increasing NE in pigs fed diets with a SID Lys:NE ratio. Overall, increasing dietary NE increased (linear, P < 0.001) daily NE intake and G:F (linear, P < 0.018) with either formulation method. However, SID Lys intake, ADG, and hot carcass weight only increased (linear, P < 0.01) when a SID Lys:NE ratio was maintained. Increasing NE without maintaining a constant SID Lys:NE ratio increased backfat depth (quadratic, P = 0.01), whereas it did not in pigs fed diets with a SID Lys:NE ratio. In conclusion, increasing dietary energy density increased NE intake and G:F regardless of formulation method. However, a SID Lys:NE ratio must be maintained to achieve increased ADG and minimize fat deposition.

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An experiment was carried out to investigate the effect of multi-enzyme in high and low levels of metabolizable energy (13.81 and 11.51 MJ kg-1 diet) on performance and energy utilization of broilers fed wheat-soybean meal diets from 0 to 21 days of age. Result showed that birds fed diets containing 11.51 MJ kg-1 consumed significantly (p < 0.05) more feed than diets containing 13.81 MJ kg-1 , whereas daily gain and feed conversion ratio improved (p < 0.05) when enzyme was added to 11.51 MJ kg-1 diet. There was significant improvement in metabolizable energy, net energy for production, organic and dry matter digestibility in 0-21 when diets supplemented with enzyme (p < 0.05). Addition of enzyme to 11.51 MJ kg-1 containing diet significantly (p < 0.05) reduced heat production of birds in 0-10 d, whereas heat production was not changed in 21 days. Supplementation of 11.51 MJ kg-1 diet with enzyme improved the efficiency of ME use for carcass energy and protein retention of broilers (p < 0.05). Generally, the results of current study demonstrated that addition of enzyme to wheat-soybean diets improved NEp of broiler chickens while MEI was not changed and it seems NEp is a more sensitive energy utilization response criterion to use in evaluating broilers response to enzyme supplementation.(AU)

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An experiment was carried out to investigate the effect of multi-enzyme in high and low levels of metabolizable energy (13.81 and 11.51 MJ kg-1 diet) on performance and energy utilization of broilers fed wheat-soybean meal diets from 0 to 21 days of age. Result showed that birds fed diets containing 11.51 MJ kg-1 consumed significantly (p < 0.05) more feed than diets containing 13.81 MJ kg-1 , whereas daily gain and feed conversion ratio improved (p < 0.05) when enzyme was added to 11.51 MJ kg-1 diet. There was significant improvement in metabolizable energy, net energy for production, organic and dry matter digestibility in 0-21 when diets supplemented with enzyme (p < 0.05). Addition of enzyme to 11.51 MJ kg-1 containing diet significantly (p < 0.05) reduced heat production of birds in 0-10 d, whereas heat production was not changed in 21 days. Supplementation of 11.51 MJ kg-1 diet with enzyme improved the efficiency of ME use for carcass energy and protein retention of broilers (p < 0.05). Generally, the results of current study demonstrated that addition of enzyme to wheat-soybean diets improved NEp of broiler chickens while MEI was not changed and it seems NEp is a more sensitive energy utilization response criterion to use in evaluating broilers response to enzyme supplementation.

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Energy partitioning and methane production by sheep fed silages of three commercially available sorghum hybrids (BRS 610, BR 700 and BRS 655) harvested at three maturation stages (milk, soft dough and floury) were evaluated in open circuit respiration chambers. A complete randomized design was used in a 3 × 3 (hybrids × maturity stages) factorial arrangement, and the means were compared by the Student-Newman-Keuls (SNK) test (P<0.05). The intake of dry matter, digestible dry matter, gross energy, digestible energy and metabolizable energy were not affected by maturation stage, but were influenced by hybrid. The net energy intake was influenced by maturity and sorghum genetics. The fecal output represented the main source of energy loss, as percentage of gross energy intake (48% to 52%), followed by heat increment (10% to 19%), methane emissions (4% to 6%) and urine (1% to 2%). There were no differences (P>0.10) among the treatments for the apparent digestibility of gross energy and metabolizability (qm). An interaction (P<0.05) between sorghum hybrid and maturation stages was observed for the efficiency of metabolizable energy utilization for maintenance (km), which ranged between 0.53 and 0.78. No differences (P>0.10) among treatments occurred in the daily methane production. There is substantial genetic diversity within sorghum species, determining different nutritional values. Sorghum genetics and maturity at harvest should not be an opportunity to reduce the contribution of agriculture to methane emissions.

A partição de energia e a produção de metano por ovinos alimentados com silagens de três híbridos de sorgo comerciais (BRS 610, BR 700 e BRS 655), colhidos em três estádios de maturação (leitoso, pastoso e farináceo), foram avaliadas em câmaras respirométricas de circuito aberto. Utilizou-se delineamento inteiramente ao acaso, em arranjo fatorial 3 x 3 (híbridos x estádios de maturação), e as médias foram comparadas pelo teste Student-Newman-Keuls (SNK) (P<0,05). Os consumos de matéria seca, de matéria seca digestível, de energia bruta, de energia digestível e de energia metabolizável não foram afetados pelo estádio de maturação, mas foram influenciados pelo híbrido de sorgo. O consumo de energia líquida foi influenciado pela maturidade e pelo híbrido. As perdas de energia nas fezes representaram a principal fonte de perda energética como porcentagem do consumo de energia bruta (48% a 52%), seguida pelo incremento calórico (10% a 19%), pela emissão de metano (4% a 6%) e pela urina (1 a 2%). Não houve diferenças (P>0,10) entre os tratamentos para a digestibilidade aparente da energia bruta e para a metabolizabilidade (qm). Foi observada interação (P<0,05) entre híbrido de sorgo e estádio de maturação para eficiência de uso da energia metabolizável para mantença (Km), que variou entre 0,53 e 0,78. Não ocorreram diferenças (P>0,10) entre tratamentos na produção diária de metano. A emissão de metano em gramas por kg de matéria seca digestível e por kg de fibra em detergente neutro digestível foi inferior no estádio pastoso comparado ao estádio farináceo.

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Energy partitioning and methane production by sheep fed silages of three commercially available sorghum hybrids (BRS 610, BR 700 and BRS 655) harvested at three maturation stages (milk, soft dough and floury) were evaluated in open circuit respiration chambers. A complete randomized design was used in a 3 × 3 (hybrids × maturity stages) factorial arrangement, and the means were compared by the Student-Newman-Keuls (SNK) test (P<0.05). The intake of dry matter, digestible dry matter, gross energy, digestible energy and metabolizable energy were not affected by maturation stage, but were influenced by hybrid. The net energy intake was influenced by maturity and sorghum genetics. The fecal output represented the main source of energy loss, as percentage of gross energy intake (48% to 52%), followed by heat increment (10% to 19%), methane emissions (4% to 6%) and urine (1% to 2%). There were no differences (P>0.10) among the treatments for the apparent digestibility of gross energy and metabolizability (qm). An interaction (P<0.05) between sorghum hybrid and maturation stages was observed for the efficiency of metabolizable energy utilization for maintenance (km), which ranged between 0.53 and 0.78. No differences (P>0.10) among treatments occurred in the daily methane production. There is substantial genetic diversity within sorghum species, determining different nutritional values. Sorghum genetics and maturity at harvest should not be an opportunity to reduce the contribution of agriculture to methane emissions(AU)

A partição de energia e a produção de metano por ovinos alimentados com silagens de três híbridos de sorgo comerciais (BRS 610, BR 700 e BRS 655), colhidos em três estádios de maturação (leitoso, pastoso e farináceo), foram avaliadas em câmaras respirométricas de circuito aberto. Utilizou-se delineamento inteiramente ao acaso, em arranjo fatorial 3 x 3 (híbridos x estádios de maturação), e as médias foram comparadas pelo teste Student-Newman-Keuls (SNK) (P<0,05). Os consumos de matéria seca, de matéria seca digestível, de energia bruta, de energia digestível e de energia metabolizável não foram afetados pelo estádio de maturação, mas foram influenciados pelo híbrido de sorgo. O consumo de energia líquida foi influenciado pela maturidade e pelo híbrido. As perdas de energia nas fezes representaram a principal fonte de perda energética como porcentagem do consumo de energia bruta (48% a 52%), seguida pelo incremento calórico (10% a 19%), pela emissão de metano (4% a 6%) e pela urina (1 a 2%). Não houve diferenças (P>0,10) entre os tratamentos para a digestibilidade aparente da energia bruta e para a metabolizabilidade (qm). Foi observada interação (P<0,05) entre híbrido de sorgo e estádio de maturação para eficiência de uso da energia metabolizável para mantença (Km), que variou entre 0,53 e 0,78. Não ocorreram diferenças (P>0,10) entre tratamentos na produção diária de metano. A emissão de metano em gramas por kg de matéria seca digestível e por kg de fibra em detergente neutro digestível foi inferior no estádio pastoso comparado ao estádio farináceo(AU)

Asunto(s)

RESUMEN

Objetivou-se com este estudo estimar as exigências nutricionais de energia e proteína em bovinos cruzados (Holandês × Zebu). Um experimento de abate comparativo foi conduzido com 44 (24 meses) bovinos cruzados pesando 338± 39 kg. Os bovinos foram aleatoriamente separados como segue: quatro bovinos para o grupo referência, quatro bovinos para o grupo mantença e 36 bovinos alimentados ad libitum. Foram uilizadas a silagem de milho (SM) e a cana-de-açúcar in natura (CA) nas proporções de 60 ou 40% na base da matéria seca (MS) total das dietas. As seis dietas experimentais foram constituídas da seguinte forma: 1) 60 SM: 40% de concentrado (C) durante 84 dias; 2) 60SM: 40C (42 dias) e 40SM:60C (42 dias); 3) 40SM:60C (84 dias); 4) 60CA:40C (84 dias); 5) 60CA:40C (42 dias) e 40CA:60C (42 dias) e 6) 40CA:60C (84 dias). Ao final do experimento, todos os animais foram abatidos para determinação do peso de corpo vazio (PCVZ). Uma amostra compreendida entre a 9ª e a 11ª costelas da meia carcaça esquerda foi retirada e completamente dissecada para a estimação da composição química do PCVZ utilizando as equações descritas no BR-CORTE em 2010. Os dados foram analisados como modelos não lineares elaborados por médias do comando NLIN do SAS (versão 9.2), ajustados pelo método de Gauss-Newton. Para todos os testes, 0.05 foi utilizado como nível crítico de probabilidade para o erro tipo I. As exi

The objective of this study was to estimate the nutritional requirements of energy and protein in crossbred (Holstein × Zebu) bulls. An experiment of comparative slaughter was conducted with 44 (24 months old) crossbred bulls of 338 ± 39 kg. Bulls were randomly separated as follows: four bulls to the control group, four bulls to the maintenance level group and 36 bulls were fed ad libitum. Corn silage (CS) and sugar cane in natura (SC) at 60 or 40% of dry matter (DM) of total diets were utilized in the diets. The bulls of the last group were randomly assigned to one of six different diets: 1) 60CS:40C(84 days); 2) 60CS:40C (42 days) and 40CS:60C (42 days); 3) 40CS:60C (84 days); 4) 60SC:40C (84 days); 5) 60SC:40C (42 days), and 40SC:60C (42 days), and 6) 40SC:60C (84 days). At the end of the experiment, bulls were slaughtered at Universidade Federal de Viçosa for estimation of the empty body weight. One sample located between the 9th and the 11th ribs of each bull was taken and completely dissected for estimation of the empty body composition using equations developed by BR-CORTE 2010. The data were analyzed as nonlinear models built by means of command NLIN of SAS (version 9.2), adjusted by the method of Gauss-Newton. For all the tests, 0.05 was utilized as critical level for probability of type I error. The net (NEm) and metabolizable (MEm) energy requirements for maintenance

RESUMEN

Objetivou-se com este estudo estimar as exigências nutricionais de energia e proteína em bovinos cruzados (Holandês × Zebu). Um experimento de abate comparativo foi conduzido com 44 (24 meses) bovinos cruzados pesando 338± 39 kg. Os bovinos foram aleatoriamente separados como segue: quatro bovinos para o grupo referência, quatro bovinos para o grupo mantença e 36 bovinos alimentados ad libitum. Foram uilizadas a silagem de milho (SM) e a cana-de-açúcar in natura (CA) nas proporções de 60 ou 40% na base da matéria seca (MS) total das dietas. As seis dietas experimentais foram constituídas da seguinte forma: 1) 60 SM: 40% de concentrado (C) durante 84 dias; 2) 60SM: 40C (42 dias) e 40SM:60C (42 dias); 3) 40SM:60C (84 dias); 4) 60CA:40C (84 dias); 5) 60CA:40C (42 dias) e 40CA:60C (42 dias) e 6) 40CA:60C (84 dias). Ao final do experimento, todos os animais foram abatidos para determinação do peso de corpo vazio (PCVZ). Uma amostra compreendida entre a 9ª e a 11ª costelas da meia carcaça esquerda foi retirada e completamente dissecada para a estimação da composição química do PCVZ utilizando as equações descritas no BR-CORTE em 2010. Os dados foram analisados como modelos não lineares elaborados por médias do comando NLIN do SAS (versão 9.2), ajustados pelo método de Gauss-Newton. Para todos os testes, 0.05 foi utilizado como nível crítico de probabilidade para o erro tipo I. As exi

The objective of this study was to estimate the nutritional requirements of energy and protein in crossbred (Holstein × Zebu) bulls. An experiment of comparative slaughter was conducted with 44 (24 months old) crossbred bulls of 338 ± 39 kg. Bulls were randomly separated as follows: four bulls to the control group, four bulls to the maintenance level group and 36 bulls were fed ad libitum. Corn silage (CS) and sugar cane in natura (SC) at 60 or 40% of dry matter (DM) of total diets were utilized in the diets. The bulls of the last group were randomly assigned to one of six different diets: 1) 60CS:40C(84 days); 2) 60CS:40C (42 days) and 40CS:60C (42 days); 3) 40CS:60C (84 days); 4) 60SC:40C (84 days); 5) 60SC:40C (42 days), and 40SC:60C (42 days), and 6) 40SC:60C (84 days). At the end of the experiment, bulls were slaughtered at Universidade Federal de Viçosa for estimation of the empty body weight. One sample located between the 9th and the 11th ribs of each bull was taken and completely dissected for estimation of the empty body composition using equations developed by BR-CORTE 2010. The data were analyzed as nonlinear models built by means of command NLIN of SAS (version 9.2), adjusted by the method of Gauss-Newton. For all the tests, 0.05 was utilized as critical level for probability of type I error. The net (NEm) and metabolizable (MEm) energy requirements for maintenance

RESUMEN

Objetivo-se avaliar o efeito diferente de tamanhos de partículas do volumoso e a frequência de alimentação sobre o metabolismo dos animais. Oito carneiros com peso vivo médio de 52,5kg foram distribuídos em esquema fatorial 2x4, de modo a corresponder a duas frequências de alimentação e quatro tamanhos (2mm; 5mm; 10mm e 25mm), em delineamento em blocos ao acaso. Foi utilizado o feno de Tifton-85 (Cynodon spp.) como volumoso e concentrado comercial, o que impôs um ajuste na relação volumoso:concentrado, que assim ficou quantificada: 25:75%. O trabalho de respirometria foi conduzido em câmara respirométrica, tipo circuito aberto, para pequenos ruminantes. Foram determinados os teores de oxigênio, gás carbônico e metano. Na urina, foi determinado o teor de nitrogênio. A partir desses parâmetros, foi determinada a produção de calor (PC). O nitrogênio retido representou 36,0% do Nitrogênio (N) ingerido (g/dia) e 46,8% do N absorvido (g/dia). A produção média de CH4 foi de 1,45L/UTM/dia. A PC foi cerca de 40,0% da energia bruta ingerida. A energia metabolizável foi 73,2% da Energia bruta ingerida e a energia líquida apresentou valor médio de 1.807,35kcal/dia. Não houve efeito dos tamanhos de partícula e da frequência sobre o balanço de nitrogênio e o metabolismo energético.

This study aimed to evaluate the effect of different forage particle sizes and the feeding frequency on the animals metabolism. Eight lambs with 52.5kg live weight were distributed in a randomized block design according the 2x4 factorial, corresponding to two feeding frequencies and four particle sizes (2mm; 5mm; 10mm and 25mm). The forage used was the Tifton-85 hay (Cynodon spp.) and commercial concentrate, adjusting the forage: concentrate ratio to 25:75%. The respirometry experiment was conducted in an open circuit respiration chamber for small ruminants. The concentrations of oxygen, carbon dioxide and methane were determined. Nitrogen content was determined in urine. With these parameters was determined heat production (PC). The nitrogen retained represented 36.0% of Nitrogen (N) intake (g/day) and 46.8% of N absorbed (g/day). The CH4 average production was 1.45L/UTM/day. The PC was approximately 40.0% of crude energy intake. The metabolizable energy was 73.2% of crude energy intake and the average value of net energy was 1807.35kcal/day. There was no effect of particle size and feeding frequency on the nitrogen balance and energy metabolism.

Asunto(s)

RESUMEN

Objetivo-se avaliar o efeito diferente de tamanhos de partículas do volumoso e a frequência de alimentação sobre o metabolismo dos animais. Oito carneiros com peso vivo médio de 52,5kg foram distribuídos em esquema fatorial 2x4, de modo a corresponder a duas frequências de alimentação e quatro tamanhos (2mm; 5mm; 10mm e 25mm), em delineamento em blocos ao acaso. Foi utilizado o feno de Tifton-85 (Cynodon spp.) como volumoso e concentrado comercial, o que impôs um ajuste na relação volumoso:concentrado, que assim ficou quantificada: 25:75%. O trabalho de respirometria foi conduzido em câmara respirométrica, tipo circuito aberto, para pequenos ruminantes. Foram determinados os teores de oxigênio, gás carbônico e metano. Na urina, foi determinado o teor de nitrogênio. A partir desses parâmetros, foi determinada a produção de calor (PC). O nitrogênio retido representou 36,0% do Nitrogênio (N) ingerido (g/dia) e 46,8% do N absorvido (g/dia). A produção média de CH4 foi de 1,45L/UTM/dia. A PC foi cerca de 40,0% da energia bruta ingerida. A energia metabolizável foi 73,2% da Energia bruta ingerida e a energia líquida apresentou valor médio de 1.807,35kcal/dia. Não houve efeito dos tamanhos de partícula e da frequência sobre o balanço de nitrogênio e o metabolismo energético.(AU)

This study aimed to evaluate the effect of different forage particle sizes and the feeding frequency on the animals metabolism. Eight lambs with 52.5kg live weight were distributed in a randomized block design according the 2x4 factorial, corresponding to two feeding frequencies and four particle sizes (2mm; 5mm; 10mm and 25mm). The forage used was the Tifton-85 hay (Cynodon spp.) and commercial concentrate, adjusting the forage: concentrate ratio to 25:75%. The respirometry experiment was conducted in an open circuit respiration chamber for small ruminants. The concentrations of oxygen, carbon dioxide and methane were determined. Nitrogen content was determined in urine. With these parameters was determined heat production (PC). The nitrogen retained represented 36.0% of Nitrogen (N) intake (g/day) and 46.8% of N absorbed (g/day). The CH4 average production was 1.45L/UTM/day. The PC was approximately 40.0% of crude energy intake. The metabolizable energy was 73.2% of crude energy intake and the average value of net energy was 1807.35kcal/day. There was no effect of particle size and feeding frequency on the nitrogen balance and energy metabolism.(AU)

Asunto(s)

RESUMEN

The net radiation (Rn) in agroecosystems is the amount of energy that is available in the environment to heating processes of living organisms, air and soil; perspiration of animals and plants; photosynthesis and water evaporation. The Rn defines the type of climate and weather conditions prevailing in a region affecting the availability and thermal water, the fundamental understanding of genotype-environment, which ultimately determine the productivity of the agricultural system. Rn usually is used in models of weather and climate studies. The sustainability and economic viability of zootechnical activity is dependent on the positive interaction between animal and environment. Environmental factors such as water, shading, thermal exchanges sensible heat (conduction, convection and radiation skin) and latent heat losses (evaporation and transpiration), conditioned by Rn, must be managed to provide the best results. The present study was conducted to develop and test models for accurate and precise radiation balance on the scales daily, monthly and seasonal ten-day for Jaboticabal - SP, due to the importance of estimates of net radiation for agricultural activities. We used daily meteorological data from weather station located in Jaboticabal, SP (coordinates: 21 14"05 "South, 48 17"09" West, 615m altitude) at Universidade Estadual Paulista "Júlio Mesquita Filho" - FCAV/UNES

O artigo não apresenta resumo em português.

RESUMEN

The net radiation (Rn) in agroecosystems is the amount of energy that is available in the environment to heating processes of living organisms, air and soil; perspiration of animals and plants; photosynthesis and water evaporation. The Rn defines the type of climate and weather conditions prevailing in a region affecting the availability and thermal water, the fundamental understanding of genotype-environment, which ultimately determine the productivity of the agricultural system. Rn usually is used in models of weather and climate studies. The sustainability and economic viability of zootechnical activity is dependent on the positive interaction between animal and environment. Environmental factors such as water, shading, thermal exchanges sensible heat (conduction, convection and radiation skin) and latent heat losses (evaporation and transpiration), conditioned by Rn, must be managed to provide the best results. The present study was conducted to develop and test models for accurate and precise radiation balance on the scales daily, monthly and seasonal ten-day for Jaboticabal - SP, due to the importance of estimates of net radiation for agricultural activities. We used daily meteorological data from weather station located in Jaboticabal, SP (coordinates: 21 14"05 "South, 48 17"09" West, 615m altitude) at Universidade Estadual Paulista "Júlio Mesquita Filho" - FCAV/UNES

O artigo não apresenta resumo em português.