DESEMPENHO E CARACTERÍSTICAS DE CARCAÇAS DE CORDEIROS ALIMENTADOS COM SILAGEM DE RAMA DE MANDIOCA

Twenty-four crossbred lambs, complete males in finishing, were used to evaluate the replacement of Tifton 85 hay by cassava foliage silage on animal performance and carcass characteristics. The animals were distributed in treatments that consisted of 4 levels of replacement of hay by cassava foliage silage (0, 33, 67 and 100%) in diets containing 60% concentrate and 40% roughage. Cassava foliage silage had lower neutral detergent fiber content (56.81%) than hay (79.71%), with higher lignin content (14.37 and 5.24%, respectively), leading at lower values of effective degradability (5%/h) and potential degradability, with greater non-degradable residue for cassava foliage silage. Body weight gain (302 g/day), dry matter intake (93.79 g/kg0.75) and feed conversion (4.63) did not differ between treatments. The carcass characteristics were affected, with a decrease in rib eye area and cover fat thickness with an increase in the replacement of Tifton 85 hay by cassava foliage silage. Cassava silage has lower nutritional value, with a higher amount of lignified fiber than hay, damaging the finishing of the lamb carcasses, but without affecting the performance of the animals.Vinte e quatro cordeiros cruzados, machos inteiros em terminação, foram utilizados para avaliar a influência da substituição do feno de Tifton 85 por silagem de rama de mandioca sobre o desempenho animal e as características de carcaças. Os animais foram distribuídos nos tratamentos que consistiram em quatro níveis de substituição do feno por silagem de rama de mandioca (0, 33, 67 e 100%) em dietas que continham 60% de concentrado e 40% de volumoso. A silagem de rama de mandioca apresentou menor teor de fibra em detergente neutro (56,81%) que o feno (79,71%), com teor de lignina mais elevado (14,37 e 5,24%, respectivamente), levando a menores valores de degradabilidade efetiva (5%/h) e degradabilidade potencial, além de apresentar maior não degradável. O ganho de peso corporal (302 g/dia), a ingestão de matéria seca (93,79 g/kg0,75) e a conversão alimentar (4,63) não apresentaram diferenças entre tratamentos. As características de carcaças foram afetadas através da diminuição da área de olho de lombo e espessura de gordura de cobertura com o aumento da substituição do feno de Tifton 85 pela silagem de rama de mandioca. Conclui-se que a silagem de rama de mandioca tem valor nutritivo inferior, com maior quantidade de fibra lignificada do que o feno, prejudicando a terminação das carcaças dos cordeiros, mas sem afetar o desempenho dos animais

Fatty acid composition of the longissimus dorsi muscle in crossbred steers fed different sources of fatty acids

The objective of this study was to evaluate the fatty acid composition of the longissimus dorsi muscle in carcasses of 3/4 Bos taurus taurus 1/4 Bos taurus indicus steers fed different sources of fatty acids. Thirty-six steers aged 14 months, with a mean live weight of 320 kg, were fed the following diets for 96 days:1) control diet, containing no supplemental fat source; 2) CaSFA, diet containing 50 g calcium salts of fatty acids per kg total dry matter; 3) CS diet, containing 210 g cottonseed per kg total dry matter. The fatty acid composition of the longissimus dorsi muscle was determined by gas chromatography. No difference in slaughter weight, carcass weight, backfat thickness, or longissimus dorsi muscle area was observed between animals receiving the diets CaSFA and CS. Animals consuming the two fat-supplemented diets presented higher concentrations of oleic (C18:1), palmitic (C16:0) and stearic (C18:0) acids, corresponding to an average 80.76% of total fatty acids, and higher concentrations of vaccenic acid (C18:1 t11) in the muscle when compared with the control group. Supplementation of the diet of feedlot crossbred steers with CaSFA or cottonseed did not promote significant alterations in the lipid composition of the longissimus dorsi muscle

Energy and protein requirements and compensatory gain composition of Nellore steers through the marker deuterium oxide

Foram utilizados 36 novilhos da raça Nelore, alojados em baias individuais em regime de confinamento, com 20 meses de idade e 359 kg no início do experimento, para determinar as exigências de energia e proteína líquidas para mantença e para ganho de peso, e também para avaliar o efeito da restrição alimentar sobre o desempenho e composição do ganho de peso, bem como o perfil hormonal dos animais e para avaliar a eficiência bioeconômica do ganho de peso compensatório em confinamento. Para isso foram realizados dois experimentos em seqüência, o primeiro teve uma duração de 58 dias e o segundo 78 dias. No primeiro foi fornecida uma mesma dieta, em três níveis de ingestão de matéria seca (MS), sendo alimentação ad libitum (TAL), 75 g MS/kg PV0,75 (T75) e 60 g MS/kg PV0,75 (T60). A composição corporal foi estimada com o óxido de deutério como marcador, que possibilitou a repetição das medidas nos mesmos animais e o estudo de suas respostas à realimentação. Os animais apresentaram exigência de energia líquida para mantença (ELm) de 0,070 Mcal/kg PV0,75 e a exigência de energia líquida para ganho (ELg) foi descrita pela equação ELg = 0,0467 * PCVz0,75 * GPCVz0,8585. A exigência de proteína metabolizável para mantença (PMm) foi determinada pela equação PMm = 4,32 * PV0,75 e a exigência de proteína metabolizável para ganho (PMg) foi de 266 g/kg GPCVz. No segundo experimento, os animais que receberam alimentação restrita na primeira fase foram alimentados ad libitum com a mesma dieta. Os hormônios avaliados foram influenciados pelo padrão de alimentação imposto aos animais e pelo ganho de peso compensatório. Animais que apresentaram ganho de peso compensatório apresentaram melhor eficiência bioeconômica.Thirty six Nellore steers with a mean weight and age of 359 kg and 20 months at the beginning of the experiment were fed individually to determine the energy and protein requirements for maintenance and gain and also to evaluate the effect of the feed restriction on the performance and gain composition, hormonal profile and bio economic efficiency during re-alimentation. Two sequential experiments were developed, the first lasted 58 days and the second 78 days. In the first the steers were fed the same diet in three levels of dry matter intake, ad libitum (TAL), 75 g DM/kg LW0,75 (T75) and 60 g DM/kg LW0,75 (T60). The body composition was estimated with the marker deuterium oxide that allowed repeated water estimative of the same animal and the re-alimentation study. The steers had a net energy requirement for maintenance (NEm) of 0,070 Mcal/kg EBW0,75 and the net energy requirement for gain (NEg) was described by the equation NEg = 0,0467 * EBW0,75 * LWGVz0,8585. The metabolizable protein requirement for maintenance (MPm) was described by the equation MPm = 4,32 * LW0,75, and the metabolizable protein for gain (MPg) was 266 g/kg ELWG. In the second experiment the animals that had restricted intake in the first phase were fed ad libitum. The hormones evaluated were influenced by the feeding pattern that the animals were submitted and by the compensatory weight gain. Animals that showed compensatory gain had greater bio economic efficiency

Performance and carcass characteristics of steers fed diets with different fat sources.

Fontes de lipídios para animais em confinamento vem sendo testadas para melhorar o desempenho animal. Neste sentido, este trabalho avaliou o desempenho animal, as características da carcaça e da maciez da carne de 36 novilhos mestiços (aproximadamente ¾ Bos taurus taurus, filhos de vacas cruzadas Simental x Nelore com touros Brangus), com idade e pesos vivos médios de 14 meses e 320 kg, respectivamente. O experimento foi realizado no setor de Bovinocultura da FZEA, USP, onde foram avaliadas três dietas com 81% de concentrado, sendo uma ração com 5% de gordura protegida (GP), uma ração com 21% de caroço de algodão (CA) e uma ração controle (CT) sem gordura adicional. A ingestão de matéria seca com a ração GP foi menor (P<0,05) que a ingestão com a ração CA, que não diferiu da ração CT, sem que o ganho médio diário e a eficiência alimentar apresentassem diferenças significativas entre os tratamentos. Os valores encontrados para a análise de uréia sangüínea estiveram dentro do considerado normal, havendo um valor significativamente maior para o tratamento CA em relação ao tratamento GP. O rendimento de carcaça, a área de olho de lombo, a espessura de gordura, a gordura renal e pélvica e o peso do fígado não foram significativamente diferentes. Os índices de pH e temperatura, tanto na primeira hora após o abate como 24 horas depois, não foram significativamente diferentes e os valores encontrados estão dentro do esperado. O índice de perda de água no cozimento não foi significativamente diferente entre os tratamentos, o mesmo ocorrendo com a análise de maciez, verificada através das forças de cisalhamento nos diferentes tempos de maturação. Os valores entre 3,0 e 3,5 kg encontrados neste trabalho correspondem a uma carne muito macia, que ainda poderia ser melhorada com a maturação por 14 dias. A gordura protegida a 5% e o caroço de algodão a 21% podem ser empregados nas rações de confinamento sem que alterem o desempenho animal ou a carcaça, sempre que o preço destes ingredientes for economicamente vantajoso.Several fat sources have been utilized in feedlot diets to improve animal performance. This study carried out at the Beef Cattle Sector of the FZEA, USP, evaluated the performance and carcass and meat characteristics of 36 crossbred steers (approximately ¾ Bos taurus taurus, offspring of crossbred Simental cow x Brangus sire), with 14 months old on the average and 320 kg, fed diets with 81% concentrate and 5% protected fat (GP), or 21% whole cotton seed (CA), or without any additional fat (CT). The dry matter intake of the GP diet was lower than with the CA diet, which was not different from the CT diet, but with no effect on daily weight gain and feed efficiency. Blood urea nitrogen was greater for the CA treatment than GP treatment, but in the normal range. Carcass dressing, rib eye area, fat thickness, kidney and pelvic fat, and liver weight were not different among treatments. The pH and temperature in the first hour and after 24 hours of chilling were not different and in the normal range. There was also no difference among treatments in water loss during cooking and Warner Bratzler shear force. The shear force values ranged from 3.0 to 3.5 kg, but were improved after 14 days of maturation. The resulted indicated that the protected fat or whole cottonseed can be used as ingredients for feedlot diets without affecting performance or carcass characteristics, if economically feasible

Mathematical model for economic analysis of diets: an application in the evaluation of different cereals in feedlot lamb´s diets

This study presents a mathematical model for economic analysis of diets composed of different ingredients. Variables such as intake and weight gain, and economic variables such as relative prices of the ingredients were considered. Twenty-four crossbred lambs, with initial age and weight of 70 days and 22 ± 1.61 kg, respectively, and final live weight of 37 ± 2.16 kg, were fed with high concentrate diets, containing different types of grains (cracked corn, whole grain corn, sorghum and millet). The animals were distributed in a complete randomized block design with four treatments and six replications, fed during 66 days and then slaughtered. The economic analysis was performed through three steps: a comparison of the productivities of production factors, comparison of commercial gross margins and comparison of the relative prices of factors of production. There was no statistical difference between the technical efficiency of the four treatments (P&gt;0.05). Treatments based on whole maize and millet presented higher economic efficiency. The use of cracked corn to replace the whole maize would only be recommended with certainty whether their prices were 24% lower than whole maize. Observing the historical behavior of prices of sorghum and millet, they could replace corn with no significant loss of production performance

Intercropping With Sorghum and Megathyrsus for Silage and Pasture Production in Integrated Systems

The search for sustainability has been arousing increasing interest in production systems that improve productivity and minimize environmental impacts. An alternative is the intercropped sowing technique, which has shown positive results in the production of silage and pasture in integrated systems. This study aimed to compare the conventional sowing of forage sorghum or intercropping with Megathyrsus maximum cv. Mombaça or M. maximum cv. Zuri for productivity (t ha-1 of green mass) and dry matter (%) of sorghum and grasses during harvest. Additionally, the number of sorghum plants per linear meter, and the dry matter and dry forage mass (FM) of grasses in the first regrowth in the intercropped treatments were evaluated. The experiment was carried out at the Instituto de Zootecnia in Ribeirão Preto, in a field of seven hectares. The experimental design was randomized blocks (three blocks) and three treatments: forage sorghum (FS), forage sorghum intercropped with Zuri (SZ) and forage sorghum intercropped with Mombaça (SM). The data obtained were submitted to analysis of variance using the PROC GLM of SAS (2013) and the differences between the means of the treatments were contrasted using the PDIFF option. Results were considered statistically significant when P<0.10. The values in t ha-1 of green mass at harvest were significantly different (P=0.07) between the treatments studied, indicating higher productivity for the intercropped treatments, regardless of the type of grass (55.34 t ha-1 for SZ and 55.66 t ha-1 for SM compared to conventional sorghum, of 34.11 t ha-1). The material harvested was ensiled with ideal values of dry matter, being 30.83% for FS, 29.75% for SZ and 31.72% for SM, with no significant difference between them (P=0.48). Zuri and Mombaça grasses yielded 29.54 t ha-1 and 25.87 t ha-1 of green mass, respectively, with no significant difference between them (P=0.63). The number of plants per linear meter of sorghum was not significantly different between treatments (P=0.23). The results were 6.58, 7.66 and 6.16 for FS, SZ and SM, respectively. The results of dry matter content and forage mass yield (t ha-1) in the first regrowth of grasses did not differ significantly (P=0.51 and P=0.50, respectively), with mean values of 22.70% and 1.45 t ha-1 for SZ and 22.30% and 1.58 t ha-1 for SM. Thus, the results show the productive benefits of the use of intercropping of sorghum with forages of the species Megathyrsus maximum for silage production, compared to conventional planting. In addition, it provides the formation of pasture for cattle in the dry season, simultaneously sharing the soil, agricultural inputs, machinery, labor and fuel, in the implementation of the systems, contributing to sustainability