Ivanor Nunes do Prado

Evaluation of carcass characteristics and meat chemical composition of Bos indicus and Bos indicus x Bos taurus crossbred steers finished in pasture systems

The objective of this study was to evaluate the carcass characteristics (carcass weight, carcass yield, fat thickness, loin area, marbling and colour) and chemical composition of the Longissimus dorsi muscle (moisture, ash, crude protein, fat and cholesterol) of cuts with or without fat thickness, of Bos indicus and Bos indicus x Bos taurus crossbred steers finished in millet (Pennisetum americanum L.) or star grass (Cynodon plectostachyus Pilger) pasture systems, with mineral or mineral protein supplementation. Animals were slaughtered with an average body weight of 450 kg (Bos indicus) or 470 kg (Bos indicus x Bos taurus crossbreed). There was no treatments effect on carcass characteristics and meat chemical composition of cut without fat thickness. The cuts with fat thickness of steers fed millet presented the highest fat deposition. Bos indicus steers presented higher carcass yield (57.23%) and fat thickness (4.88 mm) compared with crossbreed (53.40% and 3.05 mm). There was no breed effect on chemical composition of meat. The mean levels of cholesterol concentration were 31.41 mg/100 and 37.55 mg/100g of meat with and without fat thickness.

Fatty acid profile, and chemical composition of Longissimus muscle of bovine steers and bulls finished in pasture system

The objective of this work was to evaluate the conjugated linoleic acid content (CLA), the fatty acid profile, and the chemical composition of the Longissimus muscle (LM) of steers and bulls finished in pasture systems. Fourteen 1/2 Nelore×1/2 Aberdeen Angus cattle were studied. The animals were slaughtered at approximately 20 months of age, with an approximate final liveweight of 480kg. Moisture, ash, fat, crude protein, cholesterol, and fatty acid contents of Longissimus muscle were determined. Steer muscle had a higher lipid content (3.38%) than that of bulls (1.71%). Total n-3 fatty acids were higher in bulls. The amounts of CLA in steer and bull fat were similar, but the CLA content in steer muscle was higher (47.99mg100g(-1) in LM) than that in bull muscle (23.24mg100g(-1) in LM).

Degradabilidade ruminal In Situ da matéria seca e proteína bruta das silagens de milho e sorgo e de alguns alimentos concentrados

The ruminal dry matter (DM) and crude protein (CP) degradability of some feeds were evaluated by the in situ technique, using three Holstein cows. The concentrate feeds were ground through a 2 mm screen and the forage and the cassava root, in 5 mm screen, and incubated in nylon bag (53µ). The effective degradability (ED) of DM (5%/h) for corn silage, sorghum silage, corn, sorghum, wheat bran, triticale, cassava scraping, citrus pulp, soybean meal, cottonseed meal and meat and bone meal was: 54.8, 46.0, 37.6, 54.3, 80.4, 88.7, 75.0, 67.5, 74.1, 65.9, and 39.4%, respectively. The effective degradabilities CP were: 70.4, 67.9, 40.2, 42.7, 86.5, 89.3, 71.7, 62.1, 57.3, 81.4, and 47.5%, respectively. The feed group was made according to ruminal DM and CP degradation dynamics, by means of Tocher method. The potentially degradable fraction and its degradation rate were the variables of the highest discrimination power for the group formation.

Evaluation of cassava and its industrial residues in replacement of corn on performance of feedlot heifers

The objective of this work was to study the replacement of corn by cassava hulls, swept cassava meal or cassava scrapings on the average weight gain, feed intake, feed:gain ratio and carcass yields of feedlot heifers. Twenty-eight crossbreeding heifers averaging 365 kg LW and 24 months of age were allotted to a randomized blocks design in a 56 days experimental period, with four diets and seven replicates. There was no effect of replacement of corn by cassava products on average weight gain, feed:gain ratio and carcass yields. However, feed intake was smaller in the diets with cassava scrapings and by-product cassava.

Intrinsic buffering capacity of feedstuffs

Since acidosis is a major pathological risk for ruminants, we have defined a new method for the measurement of the intrinsic buffering capacity (BC) of feeds, by modeling the resistance of a feedstuff to the addition of an acid or a base. We compared results obtained on 24 feedstuffs with a strong acid and a strong base to those measured using a weak acid and a weak base which are more physiologically relevant for ruminants. The hierarchy for the BC of feedstuffs did not differ between methods, but results obtained with acetic acid (principal VFA in the rumen) seemed to be the most interesting since they can be integrated in a rumen model. The pH at which the BC were measured influenced their values. Protein content, starch content, water holding capacity (WHC) and intrinsic osmotic pressure of feedstuffs were the chemical and physical variates which best explained the variation in BC of feedstuffs. Initial pH of ingredients varied greatly between feedstuffs and was not related to chemical or physical parameters. Data obtained were in agreement with the literature when similar results were available.

Solubilidade e Degradabilidade Ruminal do Amido de Diferentes Alimentos

The starch solubility in bicarbonate-phosphate buffer (SSB) and the ruminal degradability of starch from some feed by the in situ technique, using three Holstein cows, were evaluated in this study. The feeds were ground through a 2-mm screen for the concentrate and a 5-mm screen for forage and incubated using nylon bag (53mm). The starch concentration in corn, sorghum, cassava scraping, wheat bran, triticale, corn silage, sorghum silage, soybean meal, cottonseed meal and citrus pulp were: 79.3, 83.4, 91.4, 49.1, 65.9, 31.6, 16.1, 5.5, 5.5, and 8.4%, respectively, and SSB were 13.4, 10.7, 14.0, 0.7, 20.8, 18.1, 27.0, 18.4, 68.1 and 63.3%, respectively. The effective degradability (ED) of starch was corrected (EDc) for loss of small particles during the washing process of the nylon bags using SSB values. The corn, sorghum, cassava root, wheat bran, triticale presented starch ED values of 57.8, 67.5, 79.1, 98.8, and 98.4% and EDc of: 55.5, 39.5, 62.7, 90.3, and 91.9% respectively. The observed values for ED and EDc were different only for sorghum and cassava root.

Recuperação Fecal de Indicadores Internos Avaliados em Ruminantes

This experiment was carried out to assess the fecal recuperation of the following internal markers: acid insoluble ash (AIA), acid detergent insoluble ash (ADIA), indigestible acid detergent fiber (IADF), indigestible neutral detergent fiber (INDF), and the apparent digestibility of dry matter (DM) and organic matter (OM). Four castrated sheep were used, fed with four levels of substitution of corn by cassava by-product meal. The feed samples, orts and feces were incubated in situ for 192 hours in three Holstein cows with ruminal cannula to determine the indigestible neutral detergent fiber and indigestible acid detergent fiber. The fecal recuperation of AIA and INDF were not different from 100% and had values for the digestibility coefficient of DM and OM similar to those obtained by the total feces collection method. The fecal recuperation of ADIA and IADF differed from 100%.

Características quantitativas e qualitativas da carcaça de novilhas alimentadas com diferentes fontes energéticas em dietas à base de cascas de algodão e de soja

This work was carried out to evaluate carcass characteristics, physicochemical and fatty acids compositions of Longissimus muscle from feedlot heifers fed cottonseed hulls (CSH) and soybean hulls (SBH) as forage, and different energy sources: ground corn (COR), corn germ meal (CGM) or whole rice meal (WRM). Twenty-four crossbred heifers (initial body weight of 350 ± 35 kg) were allocated in a completely randomized design into three treatments (diets) and eight replications (animals). Heifers were slaughtered after a 24-hour fasting period. Carcasses were identified, weighed and stored in a cold chamber at 2oC until following morning in order to perform carcass evaluations. The animals fed the experimental diets did not differ as carcass characteristics, the average values for hot carcass dressing were 51.4%, the loin eye area, 50.8 cm2, and fat thickness, 3.3 mm. The diets also did not influenced the physicochemical composition of Longissimus muscle, which showed 73.4% of moisture, 23.0% CP, 48.2 mg/100 g of cholesterol and 4.84 kgf/cm3 of shear force. Animals fed with CGM diet showed higher concentrations of CLA (0.48%), trans-vaccenic acid (7.69%) and worse omega 6/omega 3 ratio in the Longissimus muscle, due to the higher supply of linoleic acid provided by this diet as compared to the others. Animals fed WRM diet presented higher concentration of stearic acid in the Longissimus muscle, probably as a result of the higher content of oleic acid in this diet.

Características de carcaças e da carne de tourinhos submetidos a dietas com diferentes níveis de substituição do milho por resíduo úmido da extração da fécula de mandioca

O experimento foi realizado com o objetivo de estudar o efeito da substituicao do milho pelo residuo umido da extracao da fecula de mandioca nas proporcoes de 0, 25, 50, 75 e 100% na materia seca na dieta sobre as caracteristicas da carcaca e da carne de bovinos de corte. Foram utilizados 40 animais cruzados (½ e ¾Europeu/Zebu), nao-castrados, com 21 meses de idade e pesos medios inicial e final, de 363 e 570 kg, respectivamente, distribuidos em um delineamento em blocos, com oito repeticoes por tratamento. Nao houve efeito dos tratamentos sobre as caracteristicas avaliadas, cujos valores medios obtidos foram: rendimento de carcaca quente, 54,79%; conformacao, 12,32 (bom +); comprimento de carcaca, 132,5 cm; espessura de coxao, 28,12 cm; area do Longissimus dorsi, 79,25 cm; porcentagens de osso, 15,51%, de musculo, 64,17%, de gordura, 20,85%; relacao musculo + gordura/osso, 5,52; porcentagem da porcao comestivel, 85,07%; espessura da camada de gordura de cobertura, 4,02 mm; marmoreio, 3,9 (leve -). A composicao quimica da carne nao diferiu entre as dietas, com medias de 1,01; 19,16 e 2,24%, respectivamente para cinzas, proteina e materia graxa total. Houve diferenca significativa para umidade, com a maior porcentagem para a dieta com 50% de substituicao (74,67%) e a menor para a dieta com 25% (72,89%), ficando as demais com valores intermediarios. Nao houve influencia dos tratamentos sobre as demais variaveis. Os valores medios indicam carcacas com caracteristicas desejaveis para o mercado.

Apparent digestibility of diets containing corn or cassava hull as energy source and cottonseed meal or yeast as protein source, in heifers

ABSTRACT - Twenty-eight heifers, with average 303 kg LW were used to determine the apparent digestibility of dry matter (DM), crude protein (CP), organic matter (OM), gross energy (GE), acid detergent fiber (ADF), neutral detergent fiber (NDF) and starch in diets containing corn or cassava hull and yeast or cottonseed meal plus meat and bone meal, during seven days. The addition effect of salt or mineralized salt to the diets was also evaluated. The acid insoluble ash was used as internal maker. The digestibility of DM, OM and GE were higher for diets containing yeast compared to those ones with cottonseed meal plus meat and bone meal. The same happens for digestibilities of CP, ADF and NDF, however, only for diets containing corn as a energy source. There was no effect of protein sources on starch digestibility. The cassava hull presented higher nutrient digestibility compared to corn grain. The mineralized salt provided higher digestibility of DM, CP, OM, NDF and starch, compared to corn based diets with salt.