RESUMO

Dietary protein adjustments can reduce environmental impact and economic losses in production systems. However, we lack information regarding nitrogen (N) metabolism and protein requirements for maintenance of crossbred animals such as Red Norte breed, precluding a precise dietary management. The objective was to evaluate the effect of increasing dietary CP levels (9%, 11%, 13%, 15% and 17%) on intake, digestibility and N balance, as well as to estimate the metabolizable protein requirements for maintenance (MPm) of growing Red Norte bulls. Thirty five animals averaging 280 ± 4.0 kg BW were fed during 45 days in a 60 : 40 forage : concentrate ratio diet in which the last 5 days were used for the digestibility trial. Intakes of CP and non-fibrous carbohydrates (NFCs) and feed efficiency linearly increased (P < 0.05) as CP levels increased, while DM, NDF, nitrogen efficiency use and ether extract were not influenced by CP levels (P > 0.05). Digestibilities of DM, organic matter, ether extract, NFC and CP as well as metabolizable energy intake linearly increased (P < 0.05), and true digestibility of CP was not affected (P > 0.05) by treatments. Urinary N and retained N linearly increased (P < 0.05) with the increase in dietary N. The MPm were estimated as 4.46 g/BW0.75 and the efficiency of use of MPm was 0.673. In conclusion, obtained MPm requirements of growing Red Norte bulls are greater than the values reported in literature for Zebu cattle and dietary CP levels of 15% and 17% exhibited great responses for growing Red Norte cattle. However, a cost-benefit evaluation should be done before its use.

Assuntos

RESUMO

The objective of this study was to validate an electronic system for monitoring individual feeding and drinking behaviour and intake developed for young cattle housed in group. A total of 35 Holstein-Gyr crossbred heifers (BW: 180±52 kg; age: 121.5±32.5 days), fitted with an ear tag containing a unique passive transponder, were distributed in three groups of 12, 12 and 11 animals per period and had free access to 12 electronic feed bins and two electronic water bins (Intergado® Ltd). The dimensions of feed and water bins, as well as the sensors position were appropriate for young cattle. The system documented the visit frequency and duration, as well as the feed and water intakes, by recording the animal's identification tag, bin number, initial and final times of visits and the difference of feed/water weight at the start and end of each bin visit. Feed bins were monitored using time-lapse video recording over 4 days and the water bins were monitored over 6 days. For each feed bin, two feeding events were monitored using manual weighings with an external scale immediately before and after the animal's visit and the difference between them was assumed as feed intake (n=24 observations). For the water bins, 60 manual weighings were made. Video and manual weighing data were regressed on the electronic feeding and drinking behaviour and intake data to evaluate the system's precision and accuracy. The system showed high specificity (98.98% and 98.56% for the feed and water bins, respectively) and sensitivity (99.25% and 98.74%, respectively) for identifying an animal's presence or absence. Duration of feed and water bin visits as well as feed and water consumption per visit estimated by the system were highly correlated and precise compared with the observed video and manual weighing data (r 2=0.917, 0.963, 0.973 and 0.986, respectively). It was concluded that Intergado® system is a useful tool for monitoring feeding and drinking behaviour as well as water and feed intakes in young cattle housed in groups.

Assuntos

RESUMO

A grazing trial was carried out to evaluate the inclusion of three feed additives in supplements (crude protein, CP 230 g/kg dry matter, DM) on the performance, voluntary intake, and digestibility of beef heifers grazing Brachiaria decumbens (CP 81 and neutral detergent fiber, NDF 615 g/kg DM). Thirty-five Nellore heifers (21 months of age and 383 ± 6.29 kg of body weight, BW) were used in a completely randomized design. The treatments were as follows: no supplement (control); supplement fed at 1 kg/animal/day without additives (S); supplement with monensin (S + M); supplement with yeast culture (S + YC); and supplement with enzyme complex (S + EC). All of the supplemented heifers had greater (P < 0.1) average daily gain (∼0.186 kg/day) compared to the control treatment (0.014 kg/day). Average daily gain and final BW were similar (P > 0.1) among supplemented heifers. Monensin inclusion in the supplement decreased (P < 0.1) forage DM (expressed as g/kg BW) and NDF intake (expressed as kg/day and as g/kg BW). All of the feed additive inclusions decreased (P < 0.1) NDF digestibility. In conclusion, the heifers' performance was improved by concentrate supplementation. However, the inclusion of additives did not enhance this effect.

Assuntos

RESUMO

It is expensive and laborious to evaluate carcass composition in beef cattle. The objective of this study was to evaluate a method to predict the 9th to 11th rib section (rib) composition through empirical equations using dual energy X-ray absorptiometry (DXA). Dual energy X-ray absorptiometry is a validated method used to describe tissue composition in humans and other animals, but few studies have evaluated this technique in beef cattle, and especially in the Zebu genotype. A total of 116 rib were used to evaluate published prediction equations for rib composition and to develop new regression models using a cross-validation procedure. For the proposed models, 93 ribs were randomly selected to calculate the new regression equations, and 23 different ribs were randomly selected to validate the regressions. The rib from left carcasses were taken from Nellore and Nellore × Angus bulls from 3 different studies and scanned using DXA equipment (GE Healthcare, Madison, WI) in the Health Division at Universidade Federal de Viçosa (Viçosa, Brazil). The outputs of the DXA report were DXA lean (g), DXA fat free mass (g), DXA fat mass (g), and DXA bone mineral content (BMC; g). After being scanned, the rib were dissected, ground, and chemically analyzed for total ether extract (EE), CP, water, and ash content. The predictions of rib fat and protein from previous published equations were different ( < 0.01) from the observed composition. New equations were established through leave-one-out cross-validation using the REG procedure in SAS. The equations were as follows: lean (g) = 37.082 + 0.907× DXA lean ( = 0.95); fat free mass (g) = 103.224 + 0.869 × DXA fat free mass ( = 0.93); EE mass (g) = 122.404 + 1.119 × DXA fat mass ( = 0.86); and ash mass (g) = 18.722 + 1.016 × DXA BMC ( = 0.39). The equations were validated using Mayer's test, the concordance correlation coefficient, and the mean square error of prediction for decomposition. For both equations, Mayer's test indicated that if the intercept and the slope were equal to 0 and 1 ( > 0.05), respectively, then the equation correctly estimated the rib composition. Comparing observed and predicted values using the new equations, Mayer's test was not significant for lean mass ( = 0.26), fat free mass ( = 0.67), EE mass ( = 0.054), and ash mass ( = 0.14). We concluded that the rib composition of Nellore and Nellore × Angus bulls can be estimated from DXA using the proposed equations.

Assuntos

RESUMO

Introduzir novos alimentos na nutrição de ruminantes é essencial para maximizar desempenho e minimizar custo produtivo, entretanto, isso só é possível após se conhecer o comportamento alimentar e a disponibilidade dos seus nutrientes. Com o objetivo de avaliar o comportamento ingestivo e a digestibilidade in vivo de caprinos alimentados com níveis crescentes (0%, 2%, 4% e 7%) de copra extraída do coco verde, foram utilizados vinte caprinos machos, sem raça definida, distribuídos em delineamento inteiramente casualizado. A adição de níveis crescentes de copra de coco teve efeito quadrático no consumo de matéria seca, e no tempo diário de ruminação. Foi verificado efeito linear crescente para o tempo de ruminação de matéria seca e fibra em detergente neutro. Não houve efeito (P>0,05) nas digestibilidades aparente da matéria seca, da matéria orgânica, da fibra em detergente neutro, da fibra em detergente ácido e dos carboidratos não fibrosos, e também no consumo de carboidratos não fibrosos digestíveis, na digestibilidade aparente da hemicelulose e dos nutrientes digestíveis totais. Para a digestibilidade aparente do extrato etéreo foi verificado efeito quadrático dos níveis crescentes de inclusão de copra, enquanto que para consumo de fibra em detergente neutro digestível, digestibilidade aparente da proteína bruta, consumo de proteína bruta digestível e consumo de extrato etéreo digestível foi verificado efeito (P<0,05) linear decrescente com o aumento do nível de inclusão de copra. O melhor nível de inclusão de copra de coco para alimentação de caprinos é de 3,15% da ração total para maior consumo de matéria seca e digestibilidade aparente do extrato etéreo, sem efeitos na digestibilidade aparente da fibra em detergente neutro, mas com diminuição da digestibilidade da proteína bruta...(AU)

The introduction of new feeds in ruminant nutrition is essential to maximize performance and to minimize production costs; however, this is only possible after knowing the feeding behavior of the animals and nutrient availability. The objective of this study was to evaluate the ingestive behavior and in vivo digestibility of goats fed increasing levels (0%, 2%, 4%, and 7%) of copra extracted from green coconuts. Twenty male goats of undefined breed were allocated in a completely randomized design. The addition of increasing levels of coconut copra had a quadratic effect on dry matter intake and daily rumination time. An increasing linear effect was observed for rumination time of dry matter and neutral detergent fiber. There was no effect (P>0.05) on the apparent digestibility of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, or non-fibrous carbohydrates. The digestible non-fibrous carbohydrate intake or apparent digestibility of hemicellulose and total digestible nutrients was also not affected. A quadratic effect of increasing inclusion levels of copra was observed for apparent ether extract digestibility, while the increasing inclusion of copra had a decreasing linear effect (P<0.05) on digestible neutral detergent fiber intake, apparent crude protein digestibility, digestible crude protein intake, and digestible ether extract intake. The best inclusion level of coconut copra for goat feeding is 3.15% of the total diet to increase dry matter intake and apparent ether extract digestibility without affecting the apparent digestibility of neutral detergent fiber, but reducing crude protein digestibility...(AU)

Assuntos

RESUMO

Introduzir novos alimentos na nutrição de ruminantes é essencial para maximizar desempenho e minimizar custo produtivo, entretanto, isso só é possível após se conhecer o comportamento alimentar e a disponibilidade dos seus nutrientes. Com o objetivo de avaliar o comportamento ingestivo e a digestibilidade in vivo de caprinos alimentados com níveis crescentes (0%, 2%, 4% e 7%) de copra extraída do coco verde, foram utilizados vinte caprinos machos, sem raça definida, distribuídos em delineamento inteiramente casualizado. A adição de níveis crescentes de copra de coco teve efeito quadrático no consumo de matéria seca, e no tempo diário de ruminação. Foi verificado efeito linear crescente para o tempo de ruminação de matéria seca e fibra em detergente neutro. Não houve efeito (P>0,05) nas digestibilidades aparente da matéria seca, da matéria orgânica, da fibra em detergente neutro, da fibra em detergente ácido e dos carboidratos não fibrosos, e também no consumo de carboidratos não fibrosos digestíveis, na digestibilidade aparente da hemicelulose e dos nutrientes digestíveis totais. Para a digestibilidade aparente do extrato etéreo foi verificado efeito quadrático dos níveis crescentes de inclusão de copra, enquanto que para consumo de fibra em detergente neutro digestível, digestibilidade aparente da proteína bruta, consumo de proteína bruta digestível e consumo de extrato etéreo digestível foi verificado efeito (P<0,05) linear decrescente com o aumento do nível de inclusão de copra. O melhor nível de inclusão de copra de coco para alimentação de caprinos é de 3,15% da ração total para maior consumo de matéria seca e digestibilidade aparente do extrato etéreo, sem efeitos na digestibilidade aparente da fibra em detergente neutro, mas com diminuição da digestibilidade da proteína bruta...

The introduction of new feeds in ruminant nutrition is essential to maximize performance and to minimize production costs; however, this is only possible after knowing the feeding behavior of the animals and nutrient availability. The objective of this study was to evaluate the ingestive behavior and in vivo digestibility of goats fed increasing levels (0%, 2%, 4%, and 7%) of copra extracted from green coconuts. Twenty male goats of undefined breed were allocated in a completely randomized design. The addition of increasing levels of coconut copra had a quadratic effect on dry matter intake and daily rumination time. An increasing linear effect was observed for rumination time of dry matter and neutral detergent fiber. There was no effect (P>0.05) on the apparent digestibility of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, or non-fibrous carbohydrates. The digestible non-fibrous carbohydrate intake or apparent digestibility of hemicellulose and total digestible nutrients was also not affected. A quadratic effect of increasing inclusion levels of copra was observed for apparent ether extract digestibility, while the increasing inclusion of copra had a decreasing linear effect (P<0.05) on digestible neutral detergent fiber intake, apparent crude protein digestibility, digestible crude protein intake, and digestible ether extract intake. The best inclusion level of coconut copra for goat feeding is 3.15% of the total diet to increase dry matter intake and apparent ether extract digestibility without affecting the apparent digestibility of neutral detergent fiber, but reducing crude protein digestibility...

Assuntos

RESUMO

The objective of this study was to validate an electronic system for monitoring individual feeding behavior and feed intake (Intergado Ltd., Contagem, Minas Gerais, Brazil) in freestall-housed dairy cattle. No data have been published that validate either the behavioral measurement or the feed intake of this system. Feeding behavior data were recorded for 12 Holstein cows over 5d using an Intergado system and time-lapse video. The cows were fitted with an ear tag containing a unique passive transponder and provided free access to 12 feed bins. The system documented the visit duration and feed intake by recording the animal identification number, bin number, initial and final times, and the difference between feed weight at start and end of each feed bin visit. These data were exported to Intergado web software and reports were generated. Electronic data on animal behavior were compared with video data collected during the same evaluation period. An external scale was used to manually measure and validate the electronic system's ability to monitor dairy cow feed intake for each feed bin visit. The feed intake was manually measured for 4-h time periods and compared with the sum of the feed intake recorded by the monitoring system for each cow visit during the same time period. Video and manual weight data were regressed on the electronic feeding behavior and feeding intake data to evaluate the precision of the monitoring system. The Intergado system presented high values for specificity (99.9%) and sensitivity (99.6%) for cow detection. The visit duration and feed intake per visit collected using the electronic monitoring system were similar to the video and manual weighing data, respectively. The difference between the feed intake measured manually and the sum of the electronically recorded feed intake was less than 250g (25,635±2,428 and 25,391±2,428g estimated using manual weighing and the electronic system, respectively). In conclusion, the Intergado system is a reasonable tool to monitor feeding behavior and feed intake for freestall-housed dairy cows.

Assuntos

RESUMO

The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339±15 kg, were allotted in a completely randomized design using a 2×2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464±15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P>0.05). Subcutaneous fat from animals fed CS diet had greater C12:0, C16:0 and C18:0 contents (P<0.03). In addition, CS diets reduced the C18:1 and C18:2 cis-9, trans-11 contents in subcutaneous fat (P<0.05). The muscle from animals fed CS tended to higher C16:0 and C18:0 contents (P<0.11), and decreased C18:1, C18:2 cis-9, trans-11 and C18:3 contents (P<0.05) compared with SB. The Δ9-desaturase index was greater in muscle from animals fed SB (P<0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P<0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat.

Assuntos

RESUMO

This study evaluated the effect of feed restriction and goat genotype on meat quality. Three genotypes (Brazilian native breed Canindé; Brazilian native breed Moxotó; and F1 Boer crossbred animals obtained by crossing Boer bucks with local breed does) and three different feeding regimens (ad libitum fed, AL; restricted fed at 75% of the ad libitum, R.75; or restricted fed at 50% of the average ad libitum intake, R.50) were used. There was no difference (P>0.05) in chemical composition, total and soluble collagen, and shear force of the Longissimus lumborum muscle among genotypes. However, AL had greater amounts of soluble collagen and crude protein in the muscle (P<0.05) than R.75. No difference (P>0.05) was observed for the myofibrillar fragmentation index. The goat genotype presented few differences in their fatty acid profiles. However, goats fed ad libitum had a more favorable fatty acid profile for human health with greater concentrations of oleic acid, unsaturated fatty acids, and conjugated linoleic acid.

Assuntos

RESUMO

The objective was to evaluate the fatty acid profile and qualitative characteristics of meat from young bulls fed crude glycerin. Forty-four animals with an initial live weight of 368 ± 4 kg were used in a completely randomized design, with four treatments: no glycerin or addition of 6, 12 or 18% glycerin. The animals were slaughtered with 519.5 ± 14.9 kg of live weight. The meat characteristics assessed were chemical composition, shear force, fatty acid concentration, color and lipid oxidation. The addition of glycerin increased the content of ether extract (P<0.05) in the muscle. A linear increase was observed (P<0.05) in the oleic acid contents (C18:1 cis 9). The saturated fatty acid (SFA) contents linearly decreased in the muscle as a function of glycerin addition. The lightness (L*) and yellowness (b*) indices increased with the use of crude glycerin (P<0.05). The crude glycerin increased the intramuscular fat and oleic acid content in the longissimus dorsi muscle.

Assuntos

RESUMO

Avaliou-se o efeito da inclusão do farelo de manga em substituição ao milho moído em dietas para ovinos sobre o consumo de nutrientes e de frações fibrosas, o ganho de peso e a conversão alimentar. Estudou-se também o benefício líquido e a taxa de retorno do custo total da dieta. Foram utilizados 24 cordeiros Santa Inês, distribuídos em delineamento inteiramente ao acaso, com quatro tratamentos, constituídos pelas porcentagens de inclusão do farelo de manga, em substituição ao milho, de 0, 33, 66 e 100%, e seis repetições. Não houve efeito da inclusão do farelo de manga sobre o consumo de nutrientes e o ganho de peso dos animais. Verificou-se efeito quadrático (P<0,05) da porcentagem de inclusão do farelo de manga sobre a conversão alimentar. O farelo de manga pode substituir o milho em dietas para ovinos sem comprometer o consumo e o ganho de peso e reduz o custo da alimentação, o que sugere ser ele um alimento alternativo para ovinos em confinamento.

The effect of inclusion of mango meal to replace corn in sheep diets was evaluated. The variables evaluated were the consumption of nutrients and fibre fractions, weight gain and feed conversion. In addition, a study of the net benefit and rate of return on the total cost of the diets was conducted. Twenty-four lambs Santa Inês, distributed in a completely randomized design with four treatments, consisting of the inclusion levels of mango meal replacing corn (0, 33, 66 and 100%) and six repetitions. There was no effect of the inclusion levels of mango meal on nutrients intake and weight gain of animals. There was a quadratic effect (P<0.05) of inclusion levels of mango meal on feed conversion. The mango meal can replace corn in diets without compromising intake and weight gain, while reducing the cost of feed, indicating the possibility of alternative use as feed for confined sheep.

Assuntos

RESUMO

Avaliou-se o efeito da inclusão do farelo de manga em substituição ao milho moído em dietas para ovinos sobre o consumo de nutrientes e de frações fibrosas, o ganho de peso e a conversão alimentar. Estudou-se também o benefício líquido e a taxa de retorno do custo total da dieta. Foram utilizados 24 cordeiros Santa Inês, distribuídos em delineamento inteiramente ao acaso, com quatro tratamentos, constituídos pelas porcentagens de inclusão do farelo de manga, em substituição ao milho, de 0, 33, 66 e 100%, e seis repetições. Não houve efeito da inclusão do farelo de manga sobre o consumo de nutrientes e o ganho de peso dos animais. Verificou-se efeito quadrático (P<0,05) da porcentagem de inclusão do farelo de manga sobre a conversão alimentar. O farelo de manga pode substituir o milho em dietas para ovinos sem comprometer o consumo e o ganho de peso e reduz o custo da alimentação, o que sugere ser ele um alimento alternativo para ovinos em confinamento.(AU)

The effect of inclusion of mango meal to replace corn in sheep diets was evaluated. The variables evaluated were the consumption of nutrients and fibre fractions, weight gain and feed conversion. In addition, a study of the net benefit and rate of return on the total cost of the diets was conducted. Twenty-four lambs Santa Inês, distributed in a completely randomized design with four treatments, consisting of the inclusion levels of mango meal replacing corn (0, 33, 66 and 100%) and six repetitions. There was no effect of the inclusion levels of mango meal on nutrients intake and weight gain of animals. There was a quadratic effect (P<0.05) of inclusion levels of mango meal on feed conversion. The mango meal can replace corn in diets without compromising intake and weight gain, while reducing the cost of feed, indicating the possibility of alternative use as feed for confined sheep.(AU)

Assuntos

RESUMO

The objectives of this study were to compare visual observation and an electronic grazing time method and to evaluate the effects of nutritional plans on intake, grazing behavior and horizontal and vertical locomotion of young bulls in a tropical pasture. Thirty-nine Nellore young bulls with an average body weight of 345±9.3 kg kept in pasture were used. The experimental treatments consisted of: restricted: animals kept in a plot with a low mass of forage receiving mineral mixture only; control: animals receiving mineral mixture only; HPHC: a high protein and high carbohydrate supplement; HPLC: a high protein and low carbohydrate supplement; LPHC: a low protein and high carbohydrate supplement; LPLC: a low protein and low carbohydrate supplement. GPS collars equipped with activity sensors were used. Information about head position, latitude, longitude and altitude were recorded. Daytime grazing behavioral patterns monitored by a continuous focal animal recording method was compared to behavior estimated by the activity sensor. Feed intake was estimated by a marker method. The Restricted group presented lower (p<0.05) intake of dry matter and TDN. However, difference in dry matter intake was not found (p>0.05) between non-supplemented and supplemented animals. Difference was not found (p>0.05) in daytime grazing time obtained by visual observation or the activity sensor method. The restricted group showed longer (p<0.05) grazing time (9.58 h/d) than other groups, but difference was not found (p>0.05) in the grazing time between Control (8.35 h/d) and supplemented animals (8.03 h/d). The Restricted group presented lower (p<0.05) horizontal locomotion distance (2,168 m/d) in comparison to other groups (2,580.6 m/d). It can be concluded that the use of activity sensor methods can be recommended due to their being similar to visual observation and able to record 24-h/d. While supplements with high carbohydrates reduce pasture intake, they do not change grazing behavior. Moderate supplementation (until 50% of protein requirement and 30% of energy requirement) of beef cattle on tropical pasture has no effect on daily locomotion.

RESUMO

Avaliou-se o efeito da substituição do milho por farelo de manga em dietas para ovinos. As características avaliadas foram: consumo e digestibilidade aparente da matéria seca (MS), da proteína bruta (PB), da fibra em detergente neutro (FDN), da matéria orgânica (MO), do extrato etéreo (EE), da energia bruta (EB), da energia digestível (ED), dos carboidratos não fibrosos (CNF) e dos carboidratos totais (CT). Vinte e quatro cordeiros Santa Inês foram distribuídos em delineamento inteiramente ao acaso, com quatro tratamentos, constituídos pelas porcentagens de substituição do milho pelo farelo de manga - 0, 33, 66 e 100% -, com seis repetições. A matéria seca fecal foi estimada utilizando-se o indicador LIPE®. Não houve efeito da inclusão do farelo de manga sobre o consumo dos nutrientes e nos coeficientes de digestibilidade. Os consumos de EB e ED, em kcal/gMS, aumentaram linearmente com a inclusão do farelo de manga. O farelo de manga pode substituir o milho em dietas para ovinos, sem comprometer o consumo e a digestibilidade dos nutrientes, indicando a possibilidade de uso na dieta desses animais como alimento alternativo.

The effect of replacing corn meal with mango meal in diets of feedlot lambs was evaluated. Apparent digestibility and intakes of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), organic matter (OM) (EE), gross energy (GE), digestible energy (DE), non-fiber carbohydrates (NFC) and total carbohydrates (TC) were evaluated. Twenty-four Santa Inês lambs were distributed in a randomized design with four treatments, consisting of the replacement levels of corn meal by mango (0, 33, 66 and 100%) with six replicates. The fecal dry matter was estimated using LIPE ® external marker. There is no effect of mango meal inclusion levels on the intake and apparent digestibility. The intakes of GE and DE in kcal/gDM increase linearly with mango meal inclusion. The mango meal can replace corn in diets for lambs without compromising the intake and digestibility of nutrients, indicating potential as an alternative feed.

Assuntos

RESUMO

Avaliou-se o efeito da substituição do milho por farelo de manga em dietas para ovinos. As características avaliadas foram: consumo e digestibilidade aparente da matéria seca (MS), da proteína bruta (PB), da fibra em detergente neutro (FDN), da matéria orgânica (MO), do extrato etéreo (EE), da energia bruta (EB), da energia digestível (ED), dos carboidratos não fibrosos (CNF) e dos carboidratos totais (CT). Vinte e quatro cordeiros Santa Inês foram distribuídos em delineamento inteiramente ao acaso, com quatro tratamentos, constituídos pelas porcentagens de substituição do milho pelo farelo de manga - 0, 33, 66 e 100% -, com seis repetições. A matéria seca fecal foi estimada utilizando-se o indicador LIPE®. Não houve efeito da inclusão do farelo de manga sobre o consumo dos nutrientes e nos coeficientes de digestibilidade. Os consumos de EB e ED, em kcal/gMS, aumentaram linearmente com a inclusão do farelo de manga. O farelo de manga pode substituir o milho em dietas para ovinos, sem comprometer o consumo e a digestibilidade dos nutrientes, indicando a possibilidade de uso na dieta desses animais como alimento alternativo.(AU)

The effect of replacing corn meal with mango meal in diets of feedlot lambs was evaluated. Apparent digestibility and intakes of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), organic matter (OM) (EE), gross energy (GE), digestible energy (DE), non-fiber carbohydrates (NFC) and total carbohydrates (TC) were evaluated. Twenty-four Santa Inês lambs were distributed in a randomized design with four treatments, consisting of the replacement levels of corn meal by mango (0, 33, 66 and 100%) with six replicates. The fecal dry matter was estimated using LIPE ® external marker. There is no effect of mango meal inclusion levels on the intake and apparent digestibility. The intakes of GE and DE in kcal/gDM increase linearly with mango meal inclusion. The mango meal can replace corn in diets for lambs without compromising the intake and digestibility of nutrients, indicating potential as an alternative feed.(AU)

Assuntos

RESUMO

The objective of this study was to evaluate the effects of dietary addition of ground oilseed sources on the quality, fatty acid profile, and CLA content of meat from zebu steers. Thirty-one zebu steers with an initial average age of 23 mo and an initial BW of 365 kg were used in this study. The experimental period was 84 d, which was preceded by an adaption period of 28 d. The diet was provided ad libitum with a forage:concentrate ratio of 40:60. Corn silage was used as the forage source. Four different concentrates were formulated for each treatment: without additional lipids (control) or with ground soybeans (SB), ground cottonseed (CS), or ground linseed (LS). The SB, CS, and LS diets were formulated to have 6.5% ether extract on a total dietary DM basis. The experiment was set up as a completely randomized design. After slaughter, samples were taken from the longissimus thoracis muscle for the measurement of fatty acid concentration and the evaluation of meat quality. The luminosity index was greater in the control and LS diets (P < 0.01). The greatest percentages of myristic acid (C14:0), palmitic acid (C16:0), trans octadecenoic acid (C18:1 trans-10, trans-11, or trans-12), and SFA in the subcutaneous fat were observed in the CS treatment (P < 0.01). Moreover, the least percentages of oleic acid (C18:1 cis-9) and total unsaturated fatty acids in the subcutaneous fat were observed in the CS diet (P < 0.01). The meat linoleic acid and α-linolenic acid percentages were greatest in the SB and LS treatments, respectively (P < 0.001). The unsaturated fatty acid:SFA ratio was smallest for the CS diet (P < 0.01). A gradual increase in oxidation was observed as a function of storage time; however, the diets did not affect the rancidity of the meat (P > 0.05). The fatty acid profile of subcutaneous fat was impaired by the addition of CS. Supplying ground oilseeds did not increase the content of CLA in the meat.

Assuntos

RESUMO

A trial was carried out with four Holstein x Nellore crossbred steers (225±22kg of BW) fitted with ruminal and abomasal cannulaes in a 4 x 4 Latin Square design to evaluate the intake and the total and partial apparent digestibilities of nutrients, ruminal parameters, and microbial synthesis. Diets consisted of 60 percent silage and 40 percent concentrate formulated to be isonitrogenous (12.5 percent of crude protein, dry matter basis). Treatments consisted of different proportions of Brachiaria brizantha grass silage and sorghum silage: 100:0; 67:33; 33:67, and 0:100 percent, respectively, on dry matter basis. The intake of dry matter, organic matter, crude protein, ether extract, non-fiber carbohydrates, and total digestible nutrients linearly increased (P<0.01) as levels of sorghum silage increased. The total apparent digestibility of dry matter, organic matter, and neutral detergent fiber linearly increased with sorghum silage levels (P<0.02). The highest ruminal NH3-N (13.63mg/dL) levels occurred at 2.94h post-feeding whereas the lowest ruminal pH (5.87) was measured at 5.21h post-feeding. Microbial efficiency was not affected (P>0.05) by the treatments. The use of 67 percent of sorghum silage and 33 percent of grass silage increased intake and digestibility of nutrients without affecting ruminal pH, ruminal NH3-N, and microbial efficiency.

Realizou-se um estudo com quatro novilhos cruzados Holandês x Nelore (225±22kg de peso vivo), canulados no rúmen e abomaso, distribuídos em quadrado latino 4 x 4 para avaliar o efeito de diferentes proporções de silagem de Braquiária brizantha e silagem de sorgo sobre o consumo e a digestibilidade dos nutrientes no trato digestório total e parcial, sobre os parâmetros ruminais e sobre a eficiência microbiana. As dietas continham 60 por cento de volumoso e 40 por cento de concentrado e foram formuladas para serem isonitrogenadas (12,5 por cento de proteína bruta na matéria seca). Os tratamentos consistiram em diferentes proporções de silagens de Brachiaria brizantha e de sorgo: 100:0; 67:33; 33:67 e 0:100 por cento, respectivamente ( por cento da matéria seca). O consumo de matéria seca, matéria orgânica, proteína bruta, extrato etéreo, carboidratos não-fibrosos e nutrientes digestíveis totais aumentou linearmente (P<0,01) com o aumento da proporção de silagem de sorgo. A digestibilidade total da matéria seca, da matéria orgânica e da fibra em detergente neutro também aumentou linearmente (P<0,02) com o aumento da proporção de silagem de sorgo. A máxima concentração de N-amoniacal ruminal (13,63mg/dL) ocorreu 2,94 horas após a alimentação enquanto o menor pH foi observado às 5,21 horas após a alimentação. A eficiência microbina não foi afetada pelos tratamentos (P>0,05). O uso de 67 por cento de silagem de sorgo com 33 por cento de silagem de braquiária aumentou o consumo e a digestibilidade dos nutrientes sem afetar o pH e N-amoniacal ruminais, bem como a eficiência microbiana.

Assuntos

RESUMO

A trial was carried out with four Holstein x Nellore crossbred steers (225±22kg of BW) fitted with ruminal and abomasal cannulaes in a 4 x 4 Latin Square design to evaluate the intake and the total and partial apparent digestibilities of nutrients, ruminal parameters, and microbial synthesis. Diets consisted of 60 percent silage and 40 percent concentrate formulated to be isonitrogenous (12.5 percent of crude protein, dry matter basis). Treatments consisted of different proportions of Brachiaria brizantha grass silage and sorghum silage: 100:0; 67:33; 33:67, and 0:100 percent, respectively, on dry matter basis. The intake of dry matter, organic matter, crude protein, ether extract, non-fiber carbohydrates, and total digestible nutrients linearly increased (P<0.01) as levels of sorghum silage increased. The total apparent digestibility of dry matter, organic matter, and neutral detergent fiber linearly increased with sorghum silage levels (P<0.02). The highest ruminal NH3-N (13.63mg/dL) levels occurred at 2.94h post-feeding whereas the lowest ruminal pH (5.87) was measured at 5.21h post-feeding. Microbial efficiency was not affected (P>0.05) by the treatments. The use of 67 percent of sorghum silage and 33 percent of grass silage increased intake and digestibility of nutrients without affecting ruminal pH, ruminal NH3-N, and microbial efficiency.(AU)

Realizou-se um estudo com quatro novilhos cruzados Holandês x Nelore (225±22kg de peso vivo), canulados no rúmen e abomaso, distribuídos em quadrado latino 4 x 4 para avaliar o efeito de diferentes proporções de silagem de Braquiária brizantha e silagem de sorgo sobre o consumo e a digestibilidade dos nutrientes no trato digestório total e parcial, sobre os parâmetros ruminais e sobre a eficiência microbiana. As dietas continham 60 por cento de volumoso e 40 por cento de concentrado e foram formuladas para serem isonitrogenadas (12,5 por cento de proteína bruta na matéria seca). Os tratamentos consistiram em diferentes proporções de silagens de Brachiaria brizantha e de sorgo: 100:0; 67:33; 33:67 e 0:100 por cento, respectivamente ( por cento da matéria seca). O consumo de matéria seca, matéria orgânica, proteína bruta, extrato etéreo, carboidratos não-fibrosos e nutrientes digestíveis totais aumentou linearmente (P<0,01) com o aumento da proporção de silagem de sorgo. A digestibilidade total da matéria seca, da matéria orgânica e da fibra em detergente neutro também aumentou linearmente (P<0,02) com o aumento da proporção de silagem de sorgo. A máxima concentração de N-amoniacal ruminal (13,63mg/dL) ocorreu 2,94 horas após a alimentação enquanto o menor pH foi observado às 5,21 horas após a alimentação. A eficiência microbina não foi afetada pelos tratamentos (P>0,05). O uso de 67 por cento de silagem de sorgo com 33 por cento de silagem de braquiária aumentou o consumo e a digestibilidade dos nutrientes sem afetar o pH e N-amoniacal ruminais, bem como a eficiência microbiana.(AU)

Assuntos

RESUMO

Two trials were conducted to evaluate the effects of dietary NPN levels on animal performance, diet digestibility, ruminal characteristics, and microbial efficiency. Experiment 1 was conducted with 24 Holstein x Nellore crossbred steers (350 +/- 20 kg of BW) distributed in 6 blocks to evaluate intake and digestibility of nutrients and performance. The diets consisted of 70% corn silage and 30% concentrate (DM basis) and were formulated to contain 12.5% CP (DM basis). Treatments consisted of 0, 15.5, 31, and 46.5% of dietary N as NPN. There were no treatment differences in the daily intakes of DM (P = 0.47), OM (P = 0.60), CP (P = 0.24), nonfiber carbohydrates (NFC; P = 0.74), or TDN (P = 0.63); however, NDF intake decreased linearly as NPN increased (P = 0.02). Additionally, no effects of NPN were observed on apparent total tract digestibility of DM (P = 0.50), OM (P = 0.53), NDF (P = 0.63), or NFC (P = 0.44). The apparent total tract digestibility of CP increased linearly (P = 0.01), but ADG (1.14 kg/d) was not influenced (P = 0.96) as NPN increased. In Exp. 2, 4 ruminally and abomasally cannulated steers (300 +/- 55 kg of BW) were fed the same diet used in Exp. 1 to evaluate the effects of NPN levels on intake and digestibility of nutrients, ruminal characteristics, and microbial efficiency. There were no differences in the daily intakes of DM (P = 0.22), OM (P = 0.17), CP (P = 0.31), NDF (P = 0.29), or TDN (P = 0.49). However, NFC intake increased linearly (P = 0.02), and there was a quadratic effect (P = 0.01) on intake of ether extract as NPN increased. Ruminal digestibility of CP increased linearly (P = 0.01) with the increase of dietary NPN. There were no differences (P >or= 0.28) in microbial protein synthesis and microbial efficiency among the treatments. The results of these trials suggest that dietary NPN levels (up to 46.5% of total N) can be fed to crossbred steers receiving corn silage-based diets without affecting their growth performance or ruminal protein synthesis.

Assuntos

RESUMO

A comparative slaughter trial was conducted with 36 F1 Nellore x Red Angus calves (12 steers, 12 bulls, and 12 heifers), averaging 274 kg of BW, to assess the net requirements of protein and energy for growth and maintenance. Three cattle from each group (i.e., steers, bulls, and heifers) were slaughtered at the beginning of the trial to determine the initial body composition. The remaining calves were randomly assigned to 1 of 3 treatments: maintenance (diet containing 70% of DM as corn silage fed at 1.2% of BW daily) or concentrate at 0.75 or 1.5% of BW daily with corn silage available for ad libitum consumption. The diets were isonitrogenous (2% N, DM basis). The experimental design provided ranges in ME intake, BW, and ADG for the development of regression equations to predict the maintenance requirements for NE and net protein (MRNE and MRNP, respectively) and the growth requirement for NE and net protein (GRNE and GRNP, respectively). After 84 d of growth, the cattle were slaughtered. The cleaned gastrointestinal tracts, organs, carcasses, heads, hides, tails, feet, blood, and tissues were weighed to measure empty BW (EBW). These parts were ground separately and subsampled for chemical analyses. For each animal within a period, DMI was measured daily and samples of feces were collected to determine diet digestibility. There were no differences in MRNE (P = 0.06) among groups. The combined data indicated a MRNE of 71.2 kcal x kg(-0.75) of EBW x d(-1), with a partial efficiency of use of ME to NE(m) of 0.71. The partial efficiency of use of ME to NE for growth was 0.54 for bulls, 0.47 for steers, and 0.54 for heifers. The GRNE for steers and heifers were similar (P = 0.15) but were 18.7% greater (P = 0.03) for steers and heifers than for bulls. The MRNP did not differ among groups and averaged 2.53 g of CP x kg(-0.75) of EBW x d(-1). Likewise, GRNP was not different among groups. The percentage of retained energy deposited as protein (RE(p)) increased as the content of retained energy in the gain (RE(c), Mcal/kg of empty body gain) decreased. The RE(p) equation of the pooled data was 46.5 x e(-0.2463 x RE(c)). We conclude that the energy requirement of crossbred Bos indicus x Bos taurus for maintenance might be less than that of purebred Bos taurus and that RE(p) is nonlinearly, negatively correlated with RE(c). The GRNE was less for bulls than for steers and heifers. However, we found no differences in MRNE, MRNP, and GRNP for bulls, steers, and heifers of Nellore x Red Angus crossbreds.

Assuntos