Myofibrillar Protein Turnover in Feed-Restricted and Realimented Beef Cattle

The objective of this study was to determine the effect of feed restriction and repletion on myofibrillar protein turnover in cattle. Crossbred steer calves (n = 12) about 310 d of age were assigned randomly to a diet of corn and silage that was 1) provided ad libitum for 146 d (ALC) or 2) restricted so steers gained .2 kg/d for 80 d but received ad libitum access to feed thereafter for 66 d (RFC). At 27, 55, 97, 118 and 146 d a 24-h urine sample and a blood sample were obtained. Urine was analyzed for Nτ-methylhistidine Nτ-MH), creatinine (C), urea nitrogen (UN) and total nitrogen (TN). Serum samples were analyzed for hydroxyproliine (HYF\u27), C and albumin (A). Body weights were lower (P \u3c .05) in RFC at 55, 97, 118 and 146 d. Excretion of Nτ-MH was lower (P \u3c .05) in the RFC at 27 and 55 d but higher at 118 d Urinary C excretion was higher in ALC at the last four sample times. Urinary UN and TN excretion were lower (P \u3c .05) in RFC at 55, 97 and 118 d; urinary UN also was lower (P \u3c .05) at d 146. Serum A was higher (P \u3c .05) in ALC at 55 and 118 d, respectively. Serum HYP was higher (P \u3c .05) in RFC at 27 and 55 d. Calculated myofibrillar protein breakdown rates (FBR) and fractional synthesis rates (FSR) were higher (P \u3c .05) in RFC at the last two sampling periods; FSR was lower for the RFC at the first sampling period. Realimentation after a period of feed restriction increased both synthesis and degradation of myofibrillar protein in beef cattle

Analysis of Veal Shoulder Muscles for Chemical Attributes

The value of wholesale veal cuts varies; the rack, loin, and leg demand a premium price, while the shoulder brings little more per pound than the live animal. This study characterized the chemical properties of muscles from the veal shoulder for the potential to upgrade their value. The m. infraspinatus and m. rhomboideus fell in the intermediate or desirable groups for all traits. All nine muscles show promise in the ability to increase value

Cow Muscle Profiling: A Comparison of Chemical and Physical Properties of 21 Muscles from Beef and Dairy Cow Carcasses

About 43% of the meat from cow carcasses is sold into the boxed beef trade. This research was conducted to compare muscles from beef and dairy cows in an effort to identify optimal uses for cow muscles. Twenty-one muscles from beef and dairy cow carcasses were analyzed for objective color, total heme-iron, total collagen, pH, expressible moisture and proximate composition. Wide variation was observed for all properties measured. Effects of breed type on all measured traits were minimal except in the case of percent moisture. These results indicate muscles from beef and dairy cows are similar in chemical and physical properties. Opportunities exist to upgrade the value of selected cow muscles

Effects of Backgrounding and Growing Programs on Beef Carcass Quality and Yield

Clearly, the future of the beef cattle industry in the United States depends on the quality of the product. The majority of calves are born in the spring; therefore, to have a consistent supply of feeders entering feedlots and to take advantage of forages, a variety of stocker programs exist. Cattle enter the feedlot at varying weights and ages and from different nutritional backgrounds, and this variation could produce differences in carcass quality. The economically important measures of carcass quality are yield grade and quality grade. They are directly related: as cattle fatten in the feedlot, both quality grade and yield grade increase. Because cattle are commercially fed to fat-constant end points, it is logical to make comparisons at equal fat end points. Then, marbling (percentage Choice) becomes the primary quality criterion. We analyzed data from 534 cattle serially slaughtered and found that the percentage grading Choice increased 12 ± 1 percentage units for each 1-mm increase in rib fat. Marbling score increased 30 units (200 = slight 00) for each 1-mm increase in fat. To determine the effect of rate of winter gain on carcass quality, 372 calves over 5 yr were wintered at .23 or .61 kg/d gain. When adjusted to equal rib fat after summer grazing and finishing, there was no difference in quality grade. To test the effect of summer gain on carcass quality, 418 calves over 7 yr were followed through the feedlot after gaining .57 or .84 kg/d on grass. When compared at equal rib fat, there was no difference in quality grade. Shear force values and consumer taste panels were used to evaluate steaks from 90 cattle from calf-fed and yearling production systems. Calf-feds were 14 mo of age at slaughter and yearlings were 19 or 21 mo. Each group was serially slaughtered. There was no effect of an additional .39 cm of rib fat on shear force, juiciness, tenderness, flavor, or overall palatability. Calf-feds were significantly more tender than yearlings, but the risk of an undesirable steak from yearlings was \u3c .2% based on shear force and \u3c 2.8% based on the consumer taste panel. If cattle are fed to a common rib fat end point, and within the range of rates of winter and summer gains reported herein, we conclude that the backgrounding program has little or no effect on marbling or carcass quality grade

Effects of Dietary Antioxidant Supplementation on Cattle Finished with 30% Wet Distillers Grains Plus Solubles on Fatty Acid Profiles and Display Life

Steers were finished on either 0% wet distillers grains plus solubles or 30% wet distillers grains plus solubles with four antioxidant treatments to evaluate the effects of finishing diets containing wet distillers grains plus solubles, vitamin E and Agrado Plus on beef fatty acid profiles, discoloration and lipid oxidation of retail- displayed beef. Th e inclusion of 30% wet distillers grains plus solubles increased total polyunsaturated fatty acids of beef, but did not promote discoloration or lipid oxidation compared to the 0% wet distillers grains plus solubles diet. In both diets, feeding vitamin E alone or vitamin E+ Agrado Plus was effective in reducing lipid oxidation and maintaining color stability, while supplementing Agrado Plus alone had minimal effects in improving lipid and color stability

Consumer Visual Preference and Value for Beef Steaks Differing in Marbling Level and Color

To determine visual preference and value for fresh beef steaks differing in marbling level and color, consumers in Chicago and San Francisco (n = 124 per city) evaluated two pairs of steaks in a retail case. Steaks differing in marbling level (Modest/ Moderate vs. Slight) and color (bright, cherry-red vs. dark red) were purchased at retail stores in each city. Consumers selected their preferred steak in each pair, described their selection criteria, and provided the price they were willing to pay for each of the four steaks. There was a difference in visual preference in each city, with most consumers preferring (P \u3c 0.01) low (Slight) over high (Moderate/Modest) marbling; however, more (P \u3c 0.01) consumers in Chicago (86.7%) preferred low marbling than in San Francisco (67.0%). Selection criteria were categorized into five groups: marbling, fat, color, appearance, and palatability. Marbling was mentioned by 65.4% of consumers who preferred high marbling, whereas 64.9% of consumers who preferred low marbling mentioned fat as a selection criterion. Bright, cherry-red color was preferred by a higher (P \u3c 0.01) percentage of consumers in both Chicago and San Francisco (67.6 and 76.5%, respectively). Color was mentioned both by consumers who preferred bright, cherry-red color (64.8%) and those who preferred dark red color (63.9%). All preference groups were willing to pay more for their preferred steak (P \u3c 0.01), but consumers who preferred low marbling were willing to pay more (P \u3c 0.01) for their preferred steak than consumers who preferred high marbling. Consumers who preferred bright, cherry-red color were willing to pay more (P \u3c 0.01) for their preferred steak than consumers who preferred dark red color. Consumers who preferred low marbling seemed to desire lean products, and consumers who preferred high marbling seemed to desire products with high eating quality. In this study, consumers were willing to pay more to purchase their preferred product; however, most consumers preferred low marbling and bright, cherry-red color

Consumer Sensory Acceptance and Value of Wet-Aged and Dry-Aged Beef Steaks

To determine sensory preference and value of fresh beef steak differing in aging technique, strip steaks were evaluated by consumers in Denver (n = 132 consumers) and Chicago (n = 141 consumers). Wet-aged Choice strip loins were matched with dry-aged Choice strip loins, whereas wet-aged Prime strip loins were matched with dry-aged Prime strip loins. Dry-aged strip loins were commercially aged in air in a controlled environment for 30 d and vacuum-aged for 7 d during shipping and storage. Wet-aged strip loins were vacuum-packaged and aged for 37 d in a 1°C cooler. Pairs of strip loins were matched to similar Warner- Bratzler shear force values and marbling scores. Twelve sensory evaluation panels (of 12 scheduled panelists each) were conducted over a 3-d period in each city. Individual samples from a pair of steaks were evaluated by the panelists for sensory traits. Bids were placed on the samples after sensory traits were obtained utilizing a variation of the Vickery auction with silent, sealed bids. No significant differences for sensory traits of flavor, juiciness, tenderness, or overall acceptability were detected between wet-aged Choice samples and dry-aged Choice samples. Although wet-aged Choice samples were numerically superior for all sensory traits, consumers placed similar bid values (P = 0.12) on wet- and dry-aged Choice samples ($3.82 per 0.45 kg and$3.57 per 0.45 kg, respectively). Wet-aged Prime samples were rated more desirable (P \u3c 0.001) for flavor, tenderness, and overall acceptability than dry-aged Prime samples. Wet-aged Prime samples were valued at $4.02 per 0.45 kg, whereas dry-aged Prime samples brought$3.58 per 0.45 kg (P = 0.008). Consumers (29.3%) who preferred the dry-aged Choice samples over the wet-aged Choice samples were willing to pay $1.99/0.45 kg more (P \u3c 0.001) for dry-aged samples. The consumers who preferred the wet-aged Choice over the dry-aged Choice samples (39.2$1.77/0.45 kg more (P \u3c 0.0001). Consumers who preferred wet-aged Prime over dry-aged Prime samples (45.8%) paid $1.92/0.45 kg more (P \u3c 0.0001). Consumers who preferred dry-aged Prime samples (27.5$1.92/0.45 kg more than for the wet-aged Prime samples. Although more consumers preferred wet-aged samples, markets do exist for dry-aged beef, and consumers are willing to pay a premium for this product

Two 'b's in the Beehive: The Discovery of the First Hot Jupiters in an Open Cluster

We present the discovery of two giant planets orbiting stars in Praesepe (also known as the Beehive Cluster). These are the first known hot Jupiters in an open cluster and the only planets known to orbit Sun-like, main-sequence stars in a cluster. The planets are detected from Doppler shifted radial velocities; line bisector spans and activity indices show no correlation with orbital phase, confirming the variations are caused by planetary companions. Pr0201b orbits a V=10.52 late F dwarf with a period of 4.4264 +/- 0.0070 days and has a minimum mass of 0.540 +/- 0.039 Mjup, and Pr0211b orbits a V=12.06 late G dwarf with a period of 2.1451 +/- 0.0012 days and has a minimum mass of 1.844 +/- 0.064 Mjup. The detection of 2 planets among 53 single members surveyed establishes a lower limit on the hot Jupiter frequency of 3.8 (+5.0)(-2.4) % in this metal-rich open cluster. Given the precisely known age of the cluster, this discovery also demonstrates that, in at least 2 cases, giant planet migration occurred within 600 Myr after formation. As we endeavor to learn more about the frequency and formation history of planets, environments with well-determined properties -- such as open clusters like Praesepe -- may provide essential clues to this end.Comment: 5 pages, 3 tables, 2 figures. Published in ApJ Letter

Spectroscopic Discovery of the Supernova 2003dh Associated with GRB 030329

We present early observations of the afterglow of the Gamma-Ray Burst (GRB) 030329 and the spectroscopic discovery of its associated supernova SN 2003dh. We obtained spectra of the afterglow of GRB 030329 each night from March 30.12 (0.6 days after the burst) to April 8.13 (UT) (9.6 days after the burst). The spectra cover a wavelength range of 350 nm to 850 nm. The early spectra consist of a power-law continuum (F_nu ~ nu^{-0.9}) with narrow emission lines originating from HII regions in the host galaxy, indicating a low redshift of z=0.1687. However, our spectra taken after 2003 Apr. 5 show broad peaks in flux characteristic of a supernova. Correcting for the afterglow emission, we find the spectrum of the supernova is remarkably similar to the type Ic `hypernova' SN 1998bw. While the presence of supernovae have been inferred from the light curves and colors of GRB afterglows in the past, this is the first direct, spectroscopic confirmation that a subset of classical gamma-ray bursts originate from supernovae.Comment: published by ApJ Letters; additional material avilable at http://cfa-www.harvard.edu/cfa/oir/Research/GRB

The Influence of Diet and Oxidation on Calcium Retention of the Mitochondria in Fresh Beef

Feeding dried distillers grains (DG) may influence calcium flux postmortem by disrupting the stability of the sarcoplasmic reticulum (SR) membrane, thus leading to a higher post- rigor calcium leakage, resulting in greater activation of calpains and improved tenderness. Mitochondria provide the opportunity to study calcium flux in a controlled, tightly defined environment as a model system for the SR. Cattle were finished on diets containing either 0% DG or 50% DG. Feeding DG increased proportions of PUFA in the SR and mitochondrial membrane. Oxidized mitochondria retained less calcium than non- oxidized mitochondria. Mitochondria from cattle finished on corn tended to retain more Ca than mitochondria from cattle finished on DG. These findings suggest that feeding DG in the finishing diet can possibly increase meat tenderness through altered calcium flux