Apparent digestibility and nitrogen utilisation of diets based on maize and grass silage fed to beef steers

Substituting grass silage with maize silage in forage mixtures may result in one forage influencing the nutritive value of another in terms of whole tract nutrient digestibility and N utilisation. This experiment investigated effects of four forage combinations being, grass silage (G); 67 g/100 g grass silage + 33 g/100 g maize silage (GGM); 67 g/100 g maize silage + 33 g/100 g grass silage (MMG); maize silage (M). All diets were formulated to be isonitrogenous (22.4 g N/kg dry matter [DM]) using a concentrate mixture. Ration digestibility and N balance was determined using 7 Holstein Friesian steers (mean body weight 411.0 +/- 120.9 kg) in a cross-over design. Inclusion of maize silage in the diet had a positive linear effect on forage and total DM intake (P = 0.001), and on apparent DM and organic matter digestibility (both P = 0.048). Regardless of the silage ratio used, the metabolisable energy concentration of maize silage was calculated to be higher than that of grass silage (P = 0.058), and linearly related to the relative proportions of the two silages in the forage mixture. Inclusion of maize silage in the diet resulted in a linear decline in the apparent digestibility of starch (P = 0.022), neutral detergent fibre (P < 0.001) and acid detergent fibre (P = 0.003). Nitrogen retention, expressed as amount retained per day or in terms of body weight (g/100 kg) increased linearly with maize inclusion (P = 0.047 and 0.046, respectively). Replacing grass silage with maize silage caused linear responses according to the proportions of each forage in the diet, and that there were no associative effects of combining forages. (C) 2004 Elsevier B.V. All rights reserved.

Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of supplementation frequency on intake, behavior and performance in beef steers grazing Marandu grass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Programmed Feeding of Protein to Finishing Beef Steers

Six-hundred pound Angus steer calves were fed cornbased finishing diets for 180 days to determine the effects of stepwise reduction of protein in the diet on performance and carcass characteristics. Reducing protein in the diet, but satisfying the requirements projected by the National Research Council model for Nutrient Requirements of Beef Cattle, did not affect performance or carcass measurements. Further reduction in protein content of the diet, so the projected requirement of the rumen microorganisms was not being met, did not affect performance or carcass measurements. It is concluded that quantity of protein fed to finishing cattle can be programmed and abstantially reduced. These reductions will result in substantially less nitrogen excreted in manure from larger feedlots.

Relative effects of continuous and interrupted growth on beef steers /

Cover title.

Meat lipid profile of steers finished in pearl millet pasture with different rates of concentrate

The objective of this work was to evaluate the meat lipid profile from Devon beef steers finished in pearl millet (Pennisetum americanum) pasture and fed at different rates of concentrate supplementary diet. Twelve steers weighing 270 kg, at 12‑month‑average initial age, were randomly distributed into three treatments: pearl millet pasture; and pearl millet pasture plus a concentrate equivalent at 0.5 or 1.0% of body weight, with two replicates. Total contents of saturated and unsaturated fatty acids, the polyunsaturated:saturated ratio and other relevant fatty acids as the vaccenic acid, conjugated linoleic acid, omega‑3, and omega‑6 were not affected by the consumption of a concentrate supplement at 0.5 or 1.0% live weight. However, the 0.5% supplementation level reduced the concentration of dihomo‑γ‑linolenic fatty acid (C20: 3 n‑6), while the 1.0% supplementation level elevated the content of docosahexaenoic (DHA) (C22: 6 n‑3) fatty acid, and the omega‑6:omega‑3 ratio in meat. Consumption of up to 1.0% energy supplementation increases the omega‑6:omega‑3 ratio in meat from Devon steers grazing on pearl millet pasture.

Performance of steers supplemented with mineral mixtures in the State of Mato Grosso

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Lipid and selenium sources on fatty acid composition of intramuscular fat and muscle selenium concentration of Nellore steers

The objective of this study was to evaluate the effect of lipid and selenium sources in diets for finishing Nellore steers on the fatty acid composition and selenium concentration of the longissimus muscle. Fifty Nellore steers (body weight = 458 +/- 39 kg) were assigned to one of six dietary treatments: 1) diet containing sunflower seed and inorganic selenium; 2) sunflower seed and organic selenium; 3) whole cottonseed and inorganic selenium; 4) whole cottonseed and organic selenium; 5) soybeans and inorganic selenium; and 6) soybeans and organic selenium. Diets were formulated with the same amount of nitrogen and calories and supplied once daily to steers in collective pens, with three animals per pen, for 120 d. At the end of the trial, steers were slaughtered and samples of the longissimus muscle were collected for fatty acid and selenium analysis. Effect of selenium sources was detected for selenium concentration in the longissimus muscle. Organic selenium had higher concentrations in the meat compared with inorganic selenium. The total saturated, monounsaturated and polyunsaturated fatty acids did not differ between the sources of lipids and selenium. For selenium sources, no differences were observed between the concentrations of polyunsaturated fat. Also, no differences in C18:2 cis-9 trans-11 concentrations were noted; however, steers fed sunflower seed presented greater proportions of this fatty acid in the meat. The results indicated that the use of sunflower seed, cottonseed or soybeans and organic or inorganic selenium in feedlot diets to Nellore cattle does not alter the great part of the fatty acid profile of the longissimus muscle. However, the inclusion of sunflower seed in the diet increases the meat CLA cis-9, trans-11, which is desirable and beneficial for the health of consumers.

Effects of Feeding Calcium Salts of Conjugated Linoleic Acid (CLA) to Finishing Steers

Thirty crossbred steers were randomly assigned to three treatment groups and fed corn-based finishing diets (88% concentrate) containing 0, 1.0 or 2.5% conjugated linoleic acid (CLA) for an average of 130 days. Steers fed 2.5% CLA consumed less feed and had lower daily gains than control steers. Carcass weights tended to be reduced, and marbling scores were decreased by feeding 2.5% CLA. There were no significant effects of feeding CLA on dressing percentages, yield grades and backfat measurements. The rounds from each animal were physically separated into tissue components. Rounds from steers fed CLA contained a higher percentage of lean tissue and a lower percentage of fat. Feeding CLA increased concentrations of CLA in lipids from fat and lean in rib steaks and rounds. Increasing CLA in beef had no effects on shelf life, tenderness, juiciness, flavor or flavor intensity of rib steaks. Although results indicated that feeding calcium salts of CLA to beef steers decreased performance, concentrations of CLA in tissues could be increased offering the availability of a leaner, more healthful meat product.

Animal performance and meat characteristics in steers reared in intensive conditions fed with different vegetable oils

Enhancing the quality of beef meat is an important goal in terms of improving both the nutritional value for the consumer and the commercial value for producers. The aim of this work was to study the effects of different vegetable oil supplements on growth performance, carcass quality and meat quality in beef steers reared under intensive conditions. A total of 240 Blonde D? Aquitaine steers (average BW = 293.7 ± 38.88 kg) were grouped into 24 batches (10 steers/batch) and were randomly assigned to one of the three dietary treatments (eight batches per treatment), each supplemented with either 4% hydrogenated palm oil (PALM) or fatty acids (FAs) from olive oil (OLI) or soybean oil (SOY). No differences in growth performance or carcass quality were observed. For the meat quality analysis, a steer was randomly selected from each batch and the 6th rib on the left half of the carcass was dissected. PALM meat had the highest percentage of 16:0 ( P< 0.05) and the lowest n-6/n-3 polyunsaturated fatty acids (PUFA) ratio ( P< 0.05), OLI had the highest content of t 11-18:1 ( P< 0.01) and c 9,t 11-18:2 ( P< 0.05) and SOY showed the lowest value of monounsaturated fatty acids (MUFA) ( P< 0.001), the highest percentage of PUFA ( P< 0.01) and a lower index of atherogenicity ( P = 0.07) than PALM. No significant differences in the sensory characteristics of the meat were noted. However, the results of the principal component analysis of meat characteristics enabled meat from those steers that consumed fatty acids from olive oil to be differentiated from that of steers that consumed soybean oil.

Effect of monensin on performance in growing ruminants reared under different environmental temperatures

To evaluate the effect of monensin on the performance of growing cattle under different environmental temperatures, 24 male calves (81.9 +/- 7.7 kg mean weight and 100 days old) were distributed in a 2 x 2 factorial arrangement, contrasting 0 or 85 mg monensin/animal per day at 24.3 or 33.2 degrees C (environmental temperatures). Monensin supplementation increased weight gain (P=0.036), improved feed efficiency (P=0.040), increased ruminal concentrations of volatile fatty acids (VFA; P=0.003) and decreased the molar proportion of butyrate (P=0.034); all effects irrespective of environmental temperatures. A temperature-dependent monensin effect was detected on nitrogen retention (P=0.018) and N retained:N absorbed ratio (P=0.012). Animals fed monensin retained higher N amounts than those of the non-supplemented ones when the environmental temperature was 33.2 degrees C. Environmental temperature and monensin supplementation showed an interaction effect on urine N concentration (P=0.003). Temperature did not affect N excretion in monensin-fed animals, but increased N excretion in the non-supplemented ones. Monensin increased the crude protein (CP) digestibility (P=0.094) for