Branched-chain amino acids for growing cattle limit-fed diets based on soybean hulls

This study evaluated the effects of branched-chain amino acids on nitrogen retention and plasma branched-chain amino acid concentrations. Five ruminally cannulated Holstein steers (387 lb) were used in a 5 × 5 Latin square. Steers were limit-fed soybean hull-based diets twice daily (7.5 lb/day, as fed basis). Energy in the form of acetate (400 grams/day) was continuously infused into the rumen. Treatments were continuous abomasal infusions of 1) 115 grams/day of a mixture of 10 amino acids, 2) 10 amino acid mix with leucine removed, 3) 10 amino acid mix with isoleucine removed, 4) 10 amino acid mix with valine removed, and 5) 10 amino acid mix with all three branched-chain amino acids removed. Nitrogen retention decreased (P<0.06) in response to removal of leucine, valine, or all three branched-chain amino acids. Changes in nitrogen balance of growing cattle limit-fed soybean hull-based diets demonstrate limitations in the basal supply of leucine and valine, but not isoleucine

Soybean hulls and alfalfa for limit-fed cattle

We evaluated the optimal level of alfalfa inclusion in limit-fed, soybean hull-based diets. Steers were fed soybean hull-based diets containing 0 to 30% alfalfa or alfalfa alone. Feed intakes were lower for alfalfa than for soybean hull-based diets. Digestibilities of dry matter and neutral detergent fiber were lower (P<0.05) for alfalfa than for diets containing soybean hulls. Dry matter and neutral detergent fiber digestibilities were similar for different levels of alfalfa in diets containing soybean hulls, although there were positive associative effects between soybean hulls and alfalfa. Rates of liquid passage from the rumen were higher for alfalfa than for soybean hull-containing diets, and increased as alfalfa was added to the soybean hull diets. Solid passage rates also increased with increasing amounts of alfalfa in soybean hull-containing diets. Adding 30% alfalfa to primarily soybean hull diets led to positive associative effects on diet digestibility, but alfalfa additions increased liquid and solid passage rates, suggesting that the benefit was not a result of slower passage of soybean hulls from the rumen

Effects of nonprotein nitrogen source in blocks on rumen parameters of steers fed prairie hay

Six ruminally cannulated steers (1012 lb) were fed prairie hay ad libitum supplemented with cooked molasses blocks that contained either 60% crude protein 83% of which came from urea (UREA block) or 60% crude protein with 42% from urea and 42% from biuret (UREA/BIURET block). Blocks were broken into small pieces to facilitate consumption and were fed once daily at .125% of body weight. Rumen samples were collected on days 3, 7, 14, and 21 at 0, 1, 2, 4, 6, 8, 12, and 16 hours after feeding blocks. Averaged over time, ruminal ammonia and total volatile fatty acid concentrations and plasma urea concentrations were lower (P<.05) for steers fed the UREA/- BIURET block than for those fed the UREA block. Acetate and propionate concentrations followed patterns similar to those of total volatile fatty acids, whereas butyrate increased rapidly after block consumption. Release of ammonia from biuret was not demonstrated clearly. Ruminal ammonia concentrations were no greater with the UREA/BIURET block at times distant from feeding than with the UREA block

Improving the utilization of soybean hulls by cattle with digestive enzyme and dietary buffer supplementation

Four ruminally cannulated Holstein steers (749 lb) were used in a 4 × 4 Latin square experiment to evaluate the benefits of supplementing digestive enzymes and dietary buffers to a soybean hull-based diet fed to steers once daily at 15.4 lb/day (as fed basis). Treatments were arranged as a 2 × 2 factorial with factors being two levels (0 and 3 grams/day) of digestive enzymes and two levels (0 and 93 grams/day) of dietary buffers. Buffers and enzymes were thoroughly mixed with the soybean hull-based diet to provide a completely mixed ration. Digestive enzyme or buffer supplementation increased (P≤0.06) diet digestibilities of dry matter, organic matter, neutral detergent fiber, and acid detergent fiber. Addition of buffer also increased (P≤0.06) digestibilities of glucose, mannose, arabinose, xylose and galactose, whereas enzyme supplementation increased (P=0.03) xylose digestibilities and tended to increase (P=0.10) arabinose digestibilities. The addition of enzymes and buffer to the soybean hull-based diet did not alter passage of liquid or solids from the rumen and therefore cannot account for any of the responses in digestion. Also, ruminal pH was not altered when steers were supplemented with digestive enzyme and(or) buffer. The lack of response in pH to buffer was surprising, because the observed effect of buffer on fiber digestibilities would have been expected to be a result of a moderation of the ruminal pH. Results from this experiment demonstrated that both digestive enzyme and buffer supplementation improved the digestibility of soybean hull-based diet, and responses were greatest when both additives were supplemented together

Effects of grain processing and lipid addition to finishing diets on cattle performance and blood constituents

Experiments were conducted to evaluate effects of grain processing and lipid source on finishing cattle performance, carcass characteristics, and plasma concentrations of glucose, urea, and α-amino nitrogen (amino acids). Eighty yearling Hereford x Angus steers (847 lb) were fed diets containing either steam-flaked corn or dry-rolled corn, both fed with and without 4% added tallow. In a fifth diet, ground flaxseed (equivalent to 4% lipids) replaced a portion of steam-flaked corn. Diets were fed once daily for 85 days. As expected, cattle fed steam-flaked corn were more efficient than steers fed dry-rolled corn. Adding tallow had little effect on performance. Including flaxseed resulted in performance similar to that with tallow addition. Plasma glucose concentrations measured 2 hours after feeding were higher for steers fed steam-flaked corn than for steers fed dry-rolled corn, and were higher for cattle fed tallow than for those fed no supplemental fat. Steers fed the flax/steam-flaked corn combination had lower plasma glucose concentrations 2 hours after feeding than those fed steam flaked corn with added tallow (P<0.05). Steam flaking corn increased performance and elevated glucose concentrations compared to dry rolling, suggesting that increasing the ruminal degradable starch allowed for a greater supply of substrates for gluconeogenesis. Adding flaxseed resulted in lower levels of plasma glucose after feeding, compared to tallow

Performance of beef heifers limit-fed growing diets containing alfalfa hay and wet corn gluten feed

Three hundred thirty-nine crossbred beef heifers were used in a 99-day growing study to identify optimum combinations of alfalfa hay and wet corn gluten feed (WCGF) in limit-fed growing diets. Diets contained 10, 20, or 30% ground alfalfa hay, and 0, 40, or 68% Sweet Bran® WCGF (dry basis) in a 3 × 3 factorial arrangement of treatments. An interaction occurred (P<0.05) between level of alfalfa hay and level of WCGF for both average daily gain and feed efficiency. Increasing the levels of alfalfa hay or WCGF reduced cattle performance, with the exception of the 30% alfalfa hay and 40% WCGF diet, which supported average daily gains similar (P>0.10) to diets containing 20 or 30% alfalfa hay and no WCGF. Feed efficiencies for the 30% alfalfa hay and 40% WCGF diet were better (P<0.05) than the diet containing 30% alfalfa hay and no WCGF. Dry matter intake as measured two hours after feeding increased linearly (P<0.01) with increasing levels of alfalfa hay, and decreased linearly (P<0.01) with increasing levels of WCGF. This study suggests that including WCGF at 40% of the diet (dry basis) can effectively replace steam-flaked corn in limit-fed diets containing 20 or 30% alfalfa hay

Influence of rubber pads on vibration levels and structural behavior of subway tunnels

The principal aim of this paper is to analyze the impact of rubber pad systems on levels of vibrations and values of stresses and deformations induced in the subway tunnel segments. Thus, the 3D model has been selected to be isotropically simulated in the ANSYS program to conduct a finite element analysis. Therefore, the proposed track system in the tunnel of line 4 of the Greater Cairo Metro has been selected as an analytical and simulation case study. The impact of using eight different values for the stiffness of the rubber pad system in the case of a single tunnel has been analyzed. The results showed that levels of vibrations are significantly affected and are in logarithmic correlation with the stiffness. Also, the impact of the stiffness on the deformations and stresses are determined as well as mathematical models connecting the different parameters have been introduced

Effects of wet corn gluten feed and intake level on diet digestibility and rumen passage rate in steers

Including 40% wet corn gluten feed (WCGF) in the diet increased total tract digestion of organic matter and neutral detergent fiber (P<0.01), reduced total volatile fatty acid concentration (P<0.01), increased rumen NH3 concentration (P<0.01), increased rumen pH, and tended (P<0.06) to increase total tract digestion of starch. Furthermore, WCGF increased rumen passage rate of solid digesta (P<0.01) compared to diets containing no WCGF. Limit feeding reduced total tract digestion of organic matter and neutral detergent fiber (P<0.01), decreased total volatile fatty acid concentration (P<0.01), increased rumen NH3 concentration (P<.01), increased rumen pH at 0 and 12 hours after feeding, reduced rumen pH at 4 hours after feeding, and increased rumen liquid passage rate (P<0.02)

Addition of urea to finishing cattle diets containing steam-flaked corn and wet corn gluten feed

Three hundred thirty-nine crossbred beef heifers were used in a 74-day finishing study to evaluate effects of adding 0.5% urea to finishing diets containing steam-flaked corn and 34% (dry basis) Sweet Bran® wet corn gluten feed (WCGF). Diets were fed once daily ad libitum. Urea addition tended (P<0.06) to increase finishing average daily gain, to improve (P<0.12) feed efficiency, and to increase (P<0.06) fat thickness. Heifers fed urea had a lower percentage (P<0.03) of carcasses grading USDA Choice. This study suggests that finishing diets containing a combination of steam-flaked corn and WCGF may benefit from addition of urea as a source of supplemental ruminally available nitrogen