Estimation of the Proportion of Feed Protein Digested in the Small Intestine of Cattle Consuming Wet Corn Gluten Feed

The objectives of this study were to expand the database and determine the intestinal digestibility of rumen undegradable protein (dRUP) of common dairy feeds and to determine the effects of feeding 37.9% wet corn gluten feed on these estimates. Two ruminally and duodenally fistulated steers were assigned randomly to a crossover design with 4-wk periods. The mobile bag technique was used to determine rumen undegradable protein (RUP), dRUP, total tract digestible protein, and total tract digestible dry matter of alfalfa hay, brome hay, alfalfa haylage, corn silage, whole cottonseed, soybean meal, soyhulls, ground corn, nonenzymatically browned soybean meal, and dried distillers grains. There was no consistent effect of diet on RUP, dRUP, total tract digestible protein, and total tract digestible dry matter. The RUP (% of crude protein) ranged from 5.97% for alfalfa haylage to 75.6% for nonenzymatically browned soybean meal. The dRUP ranged from 15.3% for alfalfa haylage to 96.5% for nonenzymatically browned soybean meal. The dRUP for alfalfa hay (33.9%), brome hay (39.1%), alfalfa haylage (15.5%), and corn silage (19.9%) were lower than National Research Council reported values. The higher dRUP of the nonenzymatically browned soybean meal is reflective of more total protein reaching the small intestine. The large range in dRUP was not reflected in total tract digestible protein (% of crude protein), with corn silage being the lowest at 85.2% and nonenzymatically browned soybean meal the highest at 97.9%. In this study, diet had little effect on intestinal digestibility of protein or dry matter

Immunofluorescent Localization of RuBPCase in Degraded C\u3csub\u3e4\u3c/sub\u3e Grass Tissue

Digestion-resistant tissues found in C4 grasses may allow soluble protein to escape rumen degradation. The objective of this study was to use immunofluorescent localization to follow loss of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBPCase) from switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) parenchyma bundle sheath cells (BSC) during rumen degradation. Fluorescent signal was observed from switchgrass and big bluestem BSC through 24 and 16 h in situ digestion, respectively, and from BSC associated with both intact tissue fragments, and isolated vascular bundles in omasal digesta and fecal material from steers (Bos tarus L.) grazing switchgrass. Immunofluorescent localization demonstrated that in certain C4 grasses (i) parenchyma BSC can protect RuBPCase from degradation through 24-h in situ incubation, (ii) BSC containing RuBPCase can exit the rumen prior to degradation, and (iii) protein protected by BSC can escape degradation in the whole gastrointestinal tract and be excreted

Carcass Traits and Palatability Attributes of Herdmates Finished as Calves or Yearling Steers

A two-year study compared steers from the same herd finished as calves or yearlings at a fat thickness endpoint of 0.5 in. Yearlings yielded heavier carcasses with larger ribeye areas, lower marbling scores and lower quality grades. Calves produced more tender steaks measured by shear force and a consumer taste panel. The probability of a tough steak (based on shear force) from calf-fed steers was 1.9 and 0.02% for 7 and 21 days of aging, respectively, while the risk for yearlings was 29.2 and 4.0%, respectively. Calf-fed steers produced more tender steaks and, after 21 days of aging, steaks from yearlings were similar

Carcass Traits and Palatability Attributes of Herdmates Finished as Calves or Yearling Steers

A two-year study compared steers from the same herd finished as calves or yearlings at a fat thickness endpoint of 0.5 in. Yearlings yielded heavier carcasses with larger ribeye areas, lower marbling scores and lower quality grades. Calves produced more tender steaks measured by shear force and a consumer taste panel. The probability of a tough steak (based on shear force) from calf-fed steers was 1.9 and 0.02% for 7 and 21 days of aging, respectively, while the risk for yearlings was 29.2 and 4.0%, respectively. Calf-fed steers produced more tender steaks and, after 21 days of aging, steaks from yearlings were similar

Effect of \u3ci\u3eLactobacillus acidophilus\u3c/i\u3e Strain N P51 on\u3ci\u3e Escherichia coli \u3c/i\u3e0157:H7 Fecal Shedding and Finishing Performance in Beef Feedlot Cattle

A 2-year study was conducted during the summer months (May to September) to test the effectiveness of feeding Lactobacillus acidophilus strain NP51 on the proportion of cattle shedding Escherichia coli 0157:H7 in the feces and evaluate the effect of the treatment on finishing performance. Steers (n = 448) were assigned randomly to pens, and pens of cattle were assigned randomly to NP5 1 supplementation or no supplementation (control). NP5 1 products were mixed with water and applied as the feed was mixed daily in treatment-designated trucks at the rate of l09 CFU per steer. Fecal samples were collected (n = 3,360) from the rectum from each animal every 3 weeks, and E. coli 0157:H7 was isolated by standard procedures, using selective enrichment, immunomagnetic separation, and PCR confirmation. The outcome variable was the recovery of E. coli 0157:H7 from feces, and was modeled using logistic regression accounting for year, repeated measures of pens of cattle, and block. No significant differences were detected for gain, intakes, or feed efficiency of control or NP51-fed steers. The probability for cattle to shed E. coli 0157:H7 varied significantly between 2002 and 2003 (P = 0.004). In 2002 and 2003, the probability for NP5 1-treated steers to shed E. coli 0157:H7 over the test periods was 13 and 21 %, respectively, compared with 21 and 28% among controls. Over the 2 years, NP51-treated steers were 35% less likely to shed E. coli 0157: H7 than were steers in untreated pens (odds ratio = 0.58, P = 0.008). This study is consistent with previous reports that feeding NP51 is effective in reducing E. coli 0157:H7 fecal shedding in feedlot cattle

Carcass Traits and M. Longissimus Lumborum Palatability Attributes of Calf- and Yearling-Finished Steers

A 2-yr experiment was conducted to compare carcass characteristics and meat palatability attributes of steers (³⁄₄ British, ¹⁄₄ Continental) finished postweaning as calves or yearlings. Calves and yearlings of the same contemporary group were designated to a finishing system at weaning. Calves (n = 73) were finished in the feedlot (191 d) on a high-concentrate diet. Yearlings (n = 84) grazed crop residues after weaning, followed by spring and summer pasture grazing, and concluded with a short finishing period (91 d) in the feedlot. All steers were fed to a constant, fat thickness endpoint of 1 cm. The M. longissimus lumborum steaks from each production system were aged for 7, 14, or 21 d for Warner-Bratzler shear force determination and for 7 or 14 d for in-house sensory panel evaluation. Insoluble, percent soluble, and total collagen were determined. Yearlings produced heavier (P \u3c 0.001) carcasses with larger (P \u3c 0.001) LM areas and lower (P \u3c 0.001) marbling scores and quality grades. Calves possessed greater amounts of total collagen (P \u3c 0.001), with a significantly greater percentage of soluble collagen compared with yearlings (39.72 vs. 24.38%). Calves produced steaks with lower (P \u3c 0.001) shear force values and greater (P \u3c 0.001) sensory ratings for flavor. The USDA Choice steaks from the calves were more (P \u3c 0.001) tender and more (P \u3c 0.050) palatable than Choice steaks from yearlings, and USDA Select steaks from calves were rated more tender (P \u3c 0.001), juicy (P = 0.012), and desirable (P \u3c 0.001) than Select steaks from yearlings. As expected, increasing aging time from 7- to 14- to 21-d produced steaks with lower (P \u3c 0.001) shear force values, regardless of the production system. Risk probabilities showed 1.24% of the steaks from calf finished steers and 21.22% of steaks from yearling-finished steers to be tough. Sensory rating probabilities showed the steaks from the calves were most likely to be desirable for tenderness, whereas steaks from the yearlings were most likely to be undesirable for tenderness, juiciness, flavor, and overall acceptability. Thus, calf-finished steers produce carcasses superior in quality and palatability compared with those from yearling finished steers. However, yearling-finished steers can produce tender beef with extended aging

Relationship of Metabolizable Protein Balance, Purine Derivative Excretion, and 3-Methyl Histidine Excretion to Feed Efficiency in Individually Fed Finishing Heifers

Individually fed heifers were used to determine the relationship of 3-methyl histidine, purine derivatives, and metabolizableprotein balance to feed efficiency. Heifers were fed finishing dietsthat were either deficient or sufficient in metabolizable protein. Urine samples were collected and analyzed for early, late, and entire feeding period concentrations of 3-methyl histidine, purine derivatives, and creatinine. Results from this study indicated a negative relationship between feed efficiency and metabolizable protein balance, and no relationship between 3-methyl histidine excretion and feed efficiency, suggesting that protein turnover and microbial protein synthesis are not related to feed efficienc

Relationship of Metabolizable Protein Balance, Purine Derivative Excretion, and 3-Methyl Histidine Excretion to Feed Efficiency in Individually Fed Finishing Heifers

Individually fed heifers were used to determine the relationship of 3-methyl histidine, purine derivatives, and metabolizableprotein balance to feed efficiency. Heifers were fed finishing dietsthat were either deficient or sufficient in metabolizable protein. Urine samples were collected and analyzed for early, late, and entire feeding period concentrations of 3-methyl histidine, purine derivatives, and creatinine. Results from this study indicated a negative relationship between feed efficiency and metabolizable protein balance, and no relationship between 3-methyl histidine excretion and feed efficiency, suggesting that protein turnover and microbial protein synthesis are not related to feed efficienc

Upregulation of PTEN in Glioma Cells by Cord Blood Mesenchymal Stem Cells Inhibits Migration via Downregulation of the PI3K/Akt Pathway

PTEN (phosphatase and tensin homologue deleted on chromosome ten) is a tumor suppressor gene implicated in a wide variety of human cancers, including glioblastoma. PTEN is a major negative regulator of the PI3K/Akt signaling pathway. Most human gliomas show high levels of activated Akt, whereas less than half of these tumors carry PTEN mutations or homozygous deletions. The unique ability of mesenchymal stem cells to track down tumor cells makes them as potential therapeutic agents. Based on this capability, new therapeutic approaches have been developed using mesenchymal stem cells to cure glioblastoma. However, molecular mechanisms of interactions between glioma cells and stem cells are still unknown.In order to study the mechanisms by which migration of glioma cells can be inhibited by the upregulation of the PTEN gene, we studied two glioma cell lines (SNB19 and U251) and two glioma xenograft cell lines (4910 and 5310) alone and in co-culture with human umbilical cord blood-derived mesenchymal stem cells (hUCBSC). Co-cultures of glioma cells showed increased expression of PTEN as evaluated by immunofluorescence and immunoblotting assays. Upregulation of PTEN gene is correlated with the downregulation of many genes including Akt, JUN, MAPK14, PDK2, PI3K, PTK2, RAS and RAF1 as revealed by cDNA microarray analysis. These results have been confirmed by reverse-transcription based PCR analysis of PTEN and Akt genes. Upregulation of PTEN resulted in the inhibition of migration capability of glioma cells under in vitro conditions. Also, wound healing capability of glioma cells was significantly inhibited in co-culture with hUCBSC. Under in vivo conditions, intracranial tumor growth was inhibited by hUCBSC in nude mice. Further, hUCBSC upregulated PTEN and decreased the levels of XIAP and Akt, which are responsible for the inhibition of tumor growth in the mouse brain.Our studies indicated that upregulation of PTEN by hUCBSC in glioma cells and in the nude mice tumors downregulated Akt and PI3K signaling pathway molecules. This resulted in the inhibition of migration as well as wound healing property of the glioma cells. Taken together, our results suggest hUCBSC as a therapeutic agent in treating malignant gliomas

Effects of Optaflexx Fed in Combination with MGA on Feedlot Heifer Performance

A commercial feedlot experiment was conducted using 1,807 heifers to evaluate the effects of Optaflexx fed in combination with MGA on finishing heifer performance. In heifers receiving MGA throughout the entire 126-143 day feeding period, feeding Optaflexx for the last 31-38 days increased ADG and hot carcass weight compared to heifers fed MGA but not Optaflexx. Heifers fed MGA and Optaflexx had increased DMI, improved feed efficiency and increased final live weight. Carcass quality measurements were not influenced by treatment