Intramuscular fat and fatty acid composition of longissimus muscle from divergent pure breeds of cattle.

The objective of this study was to compare the fatty acid (FA) composition of intramuscular fat from the LM of 3 divergent breeds of cattle: Angus (AN, n = 9), Brahman (BR, n = 7), and Romosinuano (RM, n = 11). Cattle were blocked by breed and finished 129 d before slaughter in one year and 157 d in the next year. Longissimus muscle samples were collected from each carcass between the 10th and 13th ribs, trimmed of external fat, frozen in liquid nitrogen, homogenized, and used for fat extraction, using a modified Folch procedure. Extracted fat was analyzed for FA by using a GLC system with an HP-88 capillary column. Fatty acid composition was expressed using both a normalized percentage (%) and gravimetric calculation (mg/g of fresh muscle tissue) in relation to degree of saturation, which was determined using a saturation index (ratio of total SFA to total unsaturated FA). Crude fat determination revealed that LM from AN purebred cattle had the greatest amount of intramuscular fat (7.08%; P = 0.001). Although intramuscular fat of LM from RM contained a reduced percentage of total SFA (P = 0.002) compared with AN, it had the greatest percentage of total PUFA (P < 0.001 and P = 0.020). The percentages of total MUFA were similar among the 3 breeds (P = 0.675). The gravimetric calculation, a measure of actual FA concentration, showed significantly greater concentrations of SFA (26.67 mg/g), MUFA (26.50 mg/g), and PUFA (2.37 mg/g) in LM from AN cattle, as compared with LM from BR and RM cattle (P < 0.001). Interestingly, BR purebreds had the least PUFA concentration (1.49 mg/g; P

Dietary zilpaterol hydrochloride. II. Carcass composition and meat palatability of beef cattle.

Experiments were conducted at 3 US locations (California, Idaho, and Texas) to determine the effects of dietary zilpaterol hydrochloride and duration of zilpaterol feeding on carcass composition and beef palatability. At each site, 160 steers and 160 heifers were stratified within sex by initial BW (study d -1) and assigned randomly within BW strata to 1 of 4 treatments in a randomized complete block design (4 blocks/treatment for each sex). The 4 treatments were arranged in a 2 (no zilpaterol vs. zilpaterol) x 2 (20- or 40-d duration of zilpaterol feeding) factorial. When included in the diet, zilpaterol was supplemented at 8.3 mg/kg (DM basis). Each pen consisted of 10 animals. After slaughter 2 carcasses per pen (n=64 per trial site) were selected. The entire right side of the selected carcasses was collected for dissection and chemical analysis of the soft tissue. Additionally, the left strip loin was collected for Warner-Bratzler shear force determinations and aged to 28 d postmortem. Sensory analysis was conducted on the Idaho trial site samples only. All data were pooled for analyses. Feeding zilpaterol hydrochloride increased carcass muscle deposition (P<0.01) of both steer and heifer carcasses. However, carcass percentage fat of steers and heifers was not affected (P>0.11) by the zilpaterol treatment. In heifer carcasses, carcass moisture percentage was increased (P=0.04) and bone percentage was decreased (P=0.02), whereas in steer carcasses, carcass moisture and bone percentage were not affected (P>0.10). In heifer carcasses, carcass ash percentage was not affected (P=0.61) by zilpaterol, whereas in steer carcasses, carcass ash percentage tended (P=0.07) to be increased. The protein-to-bone ratio was increased (P<0.001) by zilpaterol hydrochloride treatment in both steers and heifers, whereas the protein-to-fat ratio was not affected (P=0.10). Cooking loss of the LM was not affected (P=0.41) by zilpaterol treatment of steers or heifers. However, LM Warner-Bratzler shear force was increased (P=0.003) on average (3.3 vs. 4.0 kg) due to zilpaterol hydrochloride treatment of both steers and heifers. In both steers and heifers, LM sensory panel scores of overall juiciness (6.2 vs. 6.0), tenderness (6.2 vs. 6.0), and flavor intensity (6.2 vs. 6.0) tended (P=0.06) to be decreased in cattle supplemented with zilpaterol. Zilpaterol hydrochloride is a repartitioning agent that seems to affect carcass composition primarily through protein deposition. However, zilpaterol treatment can adversely affect tenderness and other palatability traits.

Effects of feeding zilpaterol hydrochloride with and without monensin and tylosin on carcass cutability and meat palatability of beef steers.

An experiment was conducted using 200 beef carcasses to evaluate the effects of feeding zilpaterol hydrochloride with or without monensin and tylosin on carcass cutability and meat sensory variables. The experiment was conducted using a randomized complete block design with treatments arranged as a 2 (no zilpaterol vs. zilpaterol) x 2 (monensin and tylosin withdrawn vs. monensin and tylosin fed) factorial. Cattle (n=3,757) were fed zilpaterol hydrochloride, a beta(2)-adrenergic agonist, for 30 d at the end of the finishing period and withdrawn from zilpaterol hydrochloride for the last 5 d on feed. Five carcasses (weighing between 305 and 421 kg and free of slaughter defects) were selected from each of 40 feedlot treatment pens. Strip loins from the left sides were collected for sensory analysis and Warner-Bratzler shear force (WBSF) testing, and the rib was collected for 9th, 10th, 11th-rib dissections. A subsample of 3 carcass right sides per pen was fabricated into boneless subprimals according to Institutional Meat Purchase Specifications. Carcasses from zilpaterol-fed steers had greater (P or= 0.26). For the main effect of monensin and tylosin, withdrawal of monensin and tylosin decreased (P=0.01) consumer juiciness scores, although other yield and compositional measurements were not affected (P >or= 0.07). Zilpaterol is a strong repartitioning agent that increases meat yield through increased protein and decreased fat deposition.

Tasco supplementation: effects on carcass characteristics, sensory attributes, and retail display shelf-life.

Two hundred crossbred cattle (Bos indicus x Bos taurus) were supplemented with 2% Tasco (Ascophyllum nodosum) in a commercial finishing facility to evaluate marbling score, USDA quality grade, sensory traits, and retail display shelf life. Treatment animals (n = 100) received a steam-rolled corn (Zea mays)-based diet containing 2% Tasco meal (DM basis), for 14 d beginning at d 45 of the finishing period and again 14 d before slaughter. Control animals (n = 100) received a steam-rolled corn (Zea mays)-based diet without Tasco at identical feeding periods. Carcasses from Tasco-fed cattle exhibited greater marbling scores (P = 0.003) than controls. There were no treatment effects (P > 0.05) on sensory, shear, or purge attributes of striploin or inside round steaks with the exception of inside round steaks from Tasco animals having a greater initial tenderness (P = 0.03) and lower off-flavor score (P = 0.002) than control steaks. The LM samples from Tasco-fed cattle had a greater percentage of ether extractable fat (P = 0.001) and lower percentage of protein (P = 0.001) than controls. Inside round samples from treated animals exhibited a greater percentage of moisture (P = 0.03) than control steaks. Visual lean color of striploin steaks was not affected by Tasco supplementation (P = 0.26); however, steaks from Tasco-treated animals were more uniform and had less discoloration and browning than those from controls (P = 0.005, 0.04, and 0.05, respectively). Inside round visual scores and instrument values reflected similar treatment responses (P < 0.05), with a majority of the effects on muscle redness (CIE a*, hue angle) and measures of discoloration. Tasco steaks were generally more red and less discolored during extended postmortem aging and retail exposure (P < 0.05). The results from this study indicate that short-term supplementation of 2% Tasco meal in feedlot cattle increases carcass quality and prolonged retail shelf life.

Impact of transportation of feedlot cattle to the harvest facility on the prevalence of Escherichia coli 0157:H7, Salmonella, and total aerobic microorganisms on hides.

Prevalences of Escherichia coli O157:H7, Salmonella, and total aerobic microorganisms were determined on the hides of beef feedlot cattle before and after transport from the feedyard to the harvest facility in clean and dirty trailers. Swab samples were taken from the midline and withers of 40 animals on each of 8 days before and after shipping. After samples were collected, animals were loaded in groups of 10 on upper and lower levels of clean and dirty trailers. Animals were unloaded at the harvest facility and kept in treatment groups for sample collection after exsanguination. Salmonella was found more often on hide swabs collected from the midline than on than samples collected from the withers from animals transported in both clean and dirty trailers. Salmonella was found on significantly more hide swabs collected at harvest from both sampling locations than on those collected at the feedyard, with no differences attributed to the type of trailer. At the feedyard, clean trucks had a lower percentage of Salmonella-positive samples than did dirty trucks before animals were loaded. However, after transport, both clean and dirty trucks had a similar prevalence of Salmonella. There were no differences in Salmonella prevalence on hides collected from animals transported on the top and bottom levels of clean and dirty trucks. E. coli O157:H7 was detected on less than 2% of the samples; therefore, no practical conclusions about prevalence could be drawn. Hides sampled at harvest had higher concentrations of aerobic microorganisms than did hides sampled at the feedyard, and concentrations were higher on the midline than on the withers. Although the prevalences of Salmonella and total aerobic microorganisms increased on hides after transport from the feedyardto the plant, this increase was not related to the cleanliness of the trailers or the location of the cattle in the trailers.

Changes in weight and composition in various tissues of pregnant gilts and their nutritional implications.

The objectives of this study were to characterize the quantitative changes in various body tissues of high-lean type gilts during gestation and to determine the protein needs of pregnant gilts based on changes in tissue contents. Thirty-five gilts (158.2 +/- 8.3 kg) were housed in individual gestation crates with six unbred gilts randomly selected and slaughtered to provide data for d 0 of gestation. The remaining gilts were bred and assigned randomly to one of six slaughter groups: d 45, 60, 75, 90, 102, and 112. Gilts were fed 2 kg (as-fed basis) of gestation diet daily (3.1 Mcal/kg of ME and 0.56% lysine). Carcass soft tissue, bone, gastrointestinal tract, spleen, pancreas, kidney, liver, uterus, fetus, mammary gland, and the remaining viscera were separated and weighed. Carcass soft tissue, liver, remaining viscera, uterus, and gastrointestinal tract were ground, freeze-dried, and analyzed for composition. Body weights of the gilts increased quadratically (P < 0.001) during gestation. Weights of carcass soft tissue and uterus, including placenta, increased linearly (P < 0.001) during gestation. Weights of individual fetuses, fetal litters, individual mammary glands, and the entire mammary glands increased cubically (P < 0.001) during gestation. Crude protein in carcass soft tissue increased cubically (P < 0.01), whereas DM and ether extract (EE) in carcass soft tissue increased linearly (P < 0.01). The DM, CP, and EE in the entire mammary glands increased quadratically (P < 0.001) during gestation. The DM, CP, and EE in fetal litter increased cubically (P < 0.01) as gestation progressed. The accretion rates of the conceptus, fetal litter, individual fetus, individual mammary gland, and CP in fetal litter differed (P < 0.05) before and after d 70 of gestation. The CP daily gain from all maternal and fetal tissues was 40 and 103 g/d before and after d 70 of gestation, respectively, suggesting that pregnant gilts may require different quantities of dietary protein during gestation. Based on the maintenance requirement, maternal tissue gain, and conceptus gain, pregnant gilts require 6.8 and 15.3 g/d of true ileal-digestible lysine (or 147 and 330 g/d of true ileal-digestible protein) before and after d 70 of gestation, respectively, to support their true biological needs.

Effect of supplemental vitamin D3 concentration on concentrations of calcium, phosphorus, and magnesium relative to protein in subcellular components of the longissimus and the distribution of calcium within longissimus muscle of beef steers.

The effect of supplementing diets with various levels of vitamin D3 to provide 0, 0.5, 1, and 5 million IU/(steer x d) for 8 d before slaughter on the mineral content and localization of Ca in LM and muscle fragments was studied during the postmortem aging process. Twelve feedlot steers of three biological types were given access to the four levels of vitamin D for 8 d before slaughter. Differential centrifugation techniques were used to determine the concentrations of minerals relative to protein in different muscle fragments on d 3 and 21 postmortem. Electron microscopy visualization of bound Ca indicated that vitamin D3 mobilized Ca from the sarcoplasmic reticulum and transverse tubule system into the myofibrils. Bound Ca was concentrated near the Z-line at the A-band/I-band juncture within the sarcomere. Supplementing steers with 1 and 5 million IU/(steer x d) of vitamin D3 increased (P < 0.05) Ca, P, and Mg concentrations per unit of protein in the cytosol. Soluble cytosolic Ca concentrations were greater (P < 0.05) on d 21 than on d 3 postmortem only when steers were supplemented with 5 million IU/d. Concentrations of Ca, P, and Mg in isolated tissues were increased (P < 0.05) in nuclei and myofibrilar proteins by supplementing steers with 1 and 5 million IU/ (steer x d) of vitamin D3. All supplemental vitamin D3 treatments also increased (P < 0.001) Mg concentrations in the cytosol, regardless of aging treatment, and increased Mg concentrations (P < 0.04) within the mitochondria at d 3 postmortem. Thus, supplementation of feedlot steers with vitamin D3 at levels of 0.5 to 5 million IU/(steer x d) increased Ca concentrations within respiring muscle, resulting in increased bound tissue Ca concentrations. When the respiring muscle was converted to meat, the increased bound tissue Ca resulting from vitamin D3 treatment released Ca concentrations into the cytosol during aging (P < 0.05). Results of this study indicate that vitamin D3 supplementation increased total cytosolic Ca, P, and Mg concentrations in meat.

Growth and compositional changes of fetal tissues in pigs.

Three hundred twenty fetuses were obtained from 33 pregnant gilts (Camborough-22, Pig Improvement Co.) to determine rates of nutrient deposition in fetal tissues and to estimate nutrient requirements for fetal growth. Pregnant gilts were fed an equal amount of a gestation diet (2.0 kg/d; as-fed basis), and were slaughtered at d 0, 45, 60, 75, 90, 102, or 110 of gestation (n = 3 to 6 per day). Fetuses were dissected into carcass and individual tissues (including gastrointestinal tract, liver, lung, heart, kidney, spleen [> or = d 75]), and partial placental collection was made for chemical analysis. Fetal tissues were weighed and analyzed for DM, ash, CP, and crude fat. Regression equations were obtained to explain the weight and compositional changes of individual tissues during gestation. Weights of the fetus, carcass, gastrointestinal tract, liver, heart, lung, and kidney increased cubically (P < 0.001), whereas brain weight increased linearly (P < 0.001) as gestation progressed. Fetal protein and fat contents increased quadratically (P < 0.001) as gestation progressed (R2 = 0.906 and 0.904, respectively). Changes in fetal protein and fat contents fit a multiphasic regression that consisted of two linear equations (P < 0.001, R2 = 0.988 and P < 0.001, R2 = 0.983, respectively), indicating that protein and fat growth accelerated after d 69 of gestation. Fetal protein and fat accretions were 0.25 and 0.06 g/d (P < 0.001) before d 69 of gestation, and increased to 4.63 and 1.09 g/d (P < 0.001) after d 69 of gestation. Protein needs for tissue protein gains increased 19-fold after d 69 of gestation. Results of this study indicate that the growth of the fetus and fetal tissues occurs at different rates during gestation and support the practice of a two-phase feeding strategy (before and after approximately d 70 of gestation) for pregnant gilts.

Ascophyllum nodosum supplementation: a preharvest intervention for reducing Escherichia coli O157:H7 and Salmonella spp. in feedlot steers.

Ascophyllum nodosum (Tasco-14) decreased the prevalence of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in animals fed prior to harvest. Tasco-14 was supplemented on a 2% dry matter basis 14 days prior to harvest to determine its effects on EHEC and Salmonella spp. prevalence. Two hundred mixed crossbred steers and heifers (Bos indicus x Bos taurus), in a large commercial finishing facility, served as experimental units. Treatment (TRT, n = 100) animals received a steam-rolled corn-based diet containing 2% Tasco-14 on a dry matter basis, and control (CON, n = 100) animals received only the steam-rolled corn-based diet. Hide swabs and fecal samples were obtained for EHEC and Salmonella spp. evaluations. Animals were sampled 1 day prior to (d - 1) the feeding of Tasco-14 and immediately following exsanguinations. The prevalence of EHEC O157 on hide swabs and in fecal samples (P = 0.0001 and P < 0.0001, respectively) and the prevalence of EHEC O157:H7 on hide swabs and in fecal samples (P < 0.0001 and P < 0.0001, respectively) was reduced by 33 and 36% from d - 1 levels on TRT hide swabs and by 9 and 11% in TRT fecal samples. The prevalence of EHEC O157 and EHEC O157:H7 was reduced by 33 and 36% from d - 1 levels on TRT hide swabs and by 9 and 11% in TRT fecal samples. The prevalence of Salmonella spp. on hide swabs did not change for TRT animals (P = 0.64). CON animals showed an increase in Salmonella spp. prevalence (P < 0.0001) from d - 1 feeding levels on hide swabs. The prevalence of Salmonella spp. increased in both TRT and CON fecal samples when compared to d - 1 levels (P = 0.002). However, TRT samples exhibited a lower (P < 0.05) postfeeding prevalence of Salmonella spp. in fecal samples than did CON samples. Results from this study indicate that 2% Tasco-14 supplementation in feedlot cattle diets reduces EHEC O157 and EHEC O157:H7 prevalence on hide swabs and in fecal samples and may suppress increases in Salmonella spp.

Preliminary trial: motility comparisons of a unique freezing technology (UFT) to liquid nitrogen mist methodology for cryopreservation of porcine spermatozoa.

The motility outcomes of boar semen frozen with newly developed freezing techniques using a new unique freezing technology (UFT) compared with traditional liquid nitrogen methodology were investigated with the intent of improving current fertility outcomes using semen. The UFT is an electronically controlled cooling chamber that houses an organic fluid bath that can be maintained at temperatures below 0 degrees C without solidifying to freeze samples. Four ejaculates from four different boars were collected for this trial. Samples were handled consistently during the pre- and post-freeze processing. From each ejaculate, samples were separated into eight cryopreservation treatment groups, six UFT variations and two control liquid nitrogen groups, immediately before freezing, in replicates of two. After the initial cryopreservation was complete, all samples were stored in liquid nitrogen for at least 48 h. Post-thaw motilities and original motility return percentages were assessed on a random, individual-sample basis. After the initial evaluations, samples from two boars were recollected and frozen using the UFT for breeding purposes. Four sows were bred with the UFT frozen semen to confirm fertility capability. When assessing the individual UFT techniques, all of six UFT techniques had improved post-thaw motilities. However, treatments F (micro = 29%, return micro = 37%) and J (micro = 27%, return micro = 34%) showed the highest statistical improvement for post-thaw (p < 0.05) and original motility percent returns (p < 0.05) when compared with either the control cryo-tube (micro = 15%, return micro = 19%) or straw groups (micro = 12%, return micro = 16%). The UFT semen had a 50% conception rate, with an average of seven piglets from the sows that farrowed. Our preliminary data suggest a higher motility return with a slower pre-freeze phase below the freezing point before the acceleration to liquid nitrogen temperatures. The preliminary data suggest that the UFT could be utilized as a potential cryopreservation option for boar semen.

Effects of biological type of beef steers on vitamin D, calcium, and phosphorus status.

Feedlot steers (n = 36) from three biological types (Bos indicus, Bos taurus-Continental, and Bos taurus-English) were used to determine the Ca, P, and vitamin D3 status of feedlot cattle. The USDA yield and quality grade traits were measured at slaughter, and the concentrations of vitamin D3 (VITD) and the metabolites 25-hydroxyvitamin D3 (25-OH D) and 1,25-dihydroxyvitamin D3 (1,25-(OH)2 D) were determined in LM, liver, kidney, and plasma. Plasma and muscle Ca and P concentrations also were determined. Biological type of cattle affected a number of carcass traits. Carcasses from Bos taurus-English cattle had more marbling, resulting in higher quality grades (P < 0.05). Carcasses from Bos taurus-Continental cattle had lower calculated yield grades (P < 0.05) than did carcasses from cattle in the other biological types. In general, differences in carcass traits resulting from biological type were consistent with other reports. Plasma and LM Ca and P concentrations were not affected (P = 0.06) by biological type of cattle, indicating that Ca and P homeostasis is a conserved trait across the different types of cattle. Plasma VITD and 25-OH D concentrations were not affected (P = 0.41) by biological type, whereas plasma 1,25-(OH)2 D concentration was lower (P < 0.05) in Bos taurus-English cattle than in Bos taurus-Continental and Bos indicus cattle. Liver VITD and 25-OH D were not affected by biological type (P = 0.76), but liver 1,25-(OH)2 D concentration was greater (P < 0.05) in Bos indicus cattle than in Bos taurus-Continental cattle. Kidney vitamin D metabolite concentrations were not affected by biological type of cattle (P = 0.21). Muscle VITD concentration was greater (P < 0.05) in Bos taurus-English cattle than in the other two biological types, and muscle 25-OH D concentrations were greater (P < 0.05) in Bos taurus-English cattle than in Bos indicus cattle. Muscle 1,25-(OH)2 D concentration was less (P < 0.05) in the Bos taurus-Continental cattle than in the other two biological types. Cooking eliminated vitamin D metabolite differences among the biological types. Our results suggest that Bos indicus cattle had greater 1,25-(OH)2 D (the biologically active form) in tissues, and greater 1,25-(OH)2 D plasma concentrations than Bos taurus cattle. Thus, the need for VITD supplementation and optimal levels of Ca and P in feedlot diets might differ between Bos indicus and Bos taurus cattle.

Supplemental vitamin D3 concentration and biological type of beef steers. I. Feedlot performance and carcass traits.

Because of the Ca dependency of the calpains, oral supplementation of vitamin D3 (VITD) can increase the Ca content of muscle to activate the calpains and improve tenderness. Feedlot steers (n = 142) were arranged in a 4 x 3 factorial arrangement consisting of four levels of VITD (0, 0.5, 1, and 5 million IU/[steer x d]) for eight consecutive days antemortem using three biological types (Bos indicus, Bos taurus-Continental, and Bos taurus-English). Feedlot performance factors of ADG, DMI, and G:F were measured, and carcass quality, yield, and color data were collected. Plasma Ca and P concentrations were measured during d 4 to 6 of supplementation and at exsanguination, and carcass pH and temperature were measured in the LM at 3 and 24 h postmortem. Vitamin D3 treatment at 5 million IU/(steer x d) decreased ADG (P < 0.05) over the supplementation and feed intake for the last 2 d of feeding compared with untreated control steers. Likewise, G:F was decreased (P = 0.03) in steers supplemented with 5 million IU/d compared with controls. Overall, there was a linear decrease (P < 0.01) in ADG and G:F as a result of VITD supplementation. Plasma concentrations of Ca and P were increased (P < 0.05) by VITD concentrations of 1 and 5 million IU/(steer x d). All VITD treatments increased (P < 0.05) LM temperature at 3 h postmortem and pH at 24 h postmortem. Vitamin D3 treatments did not affect (P = 0.07) any other carcass measurements, including USDA yield and quality grade; thus, any improvements in meat tenderness as a result of VITD supplementation can be made without adversely affecting economically important carcass factors. Biological type of cattle did not interact with VITD treatment for any carcass or feedlot performance trait. Although feeding 5 million IU/(steer x d) of VITD for eight consecutive days had negative effects on performance, supplementing VITD at 0.5 million IU/ (steer x d) did not significantly alter feedlot performance.

Supplemental vitamin D3 concentration and biological type of steers. II. Tenderness, quality, and residues of beef.

Vitamin D3 was orally supplemented to determine the supplemental dose that improved beef tenderness in different cattle breed types. Feedlot steers (n = 142) were arranged in a 4 x 3 factorial arrangement consisting of four levels of supplemental vitamin D3 (0, 0.5, 1, and 5 million IU/steer daily) administered for eight consecutive days antemortem using three biological types (Bos indicus, Bos Taurus-Continental, and Bos Taurus-English). Warner-Bratzler shear force (WBSF) was measured at 3, 7, 10, 14, and 21 d postmortem, and trained sensory analysis was conducted at 7 d postmortem on LM, semimembranosus, gluteus medius, and supraspinatus steaks. Concentrations of vitamin D3 and the metabolites 25-hydroxyvitamin D3, and 1,25-dihydroxyvitamin D3 were determined in the LM, liver, kidney, and plasma. Biological type of cattle did not interact (P > 0.10) with vitamin D3 supplementation for sensory or tenderness traits, suggesting that feeding vitamin D3 for 8 d before slaughter affected the different biological types of cattle similarly. Supplementing steers with 0.5, 1, or 5 million IU/(steer(d) decreased (P < 0.05) LM WBSF at 7, 10, 14, and 21 d postmortem compared with controls, and vitamin D3 treatments of 0.5, 1, and 5 million IU decreased (P < 0.05) semimembranosus WBSF at 3, 7, and 14 d postmortem. In general, vitamin D3-induced improvements in WBSF were most consistent and intense in LM steaks. Sensory panel tenderness was improved (P < 0.05) by all vitamin D3 treatments in LM steaks. Sensory traits ofjuiciness, flavor, connective tissue, and off-flavor were not (P > 0.05) affected by vitamin D3 treatments. All vitamin D3 treatments decreased micro-calpain activity and increased muscle Ca concentrations (P < 0.05). Vitamin D3 concentrations were increased (P < 0.05) by supplementation in all tissues tested (liver, kidney, LM, and plasma); however, cooking steaks to 71 degrees C decreased (P < 0.05) treatment residue effects. The vitamin D metabolite 1,25-dihydroxyvitamin D3 was increased (P < 0.05) only in plasma samples as a result of the vitamin D3 treatments. These results indicate that supplementation with vitamin D3 at 0.5 million IU/steer daily for eight consecutive days before slaughter improved tenderness in steaks from different subprimal cuts by affecting muscle Ca concentrations, micro-calpain activities, and muscle proteolysis, with only a small effect on tissue residues of vitamin D3.

Environmental effects on pig performance, meat quality, and muscle characteristics.

The objective of this experiment was to determine the effect of diverse production systems on pig performance, muscle characteristics, and their relation to pork quality measures. Birth and rearing conditions were evaluated using 48 barrows during the fall/winter months. Pigs were farrowed in either indoor crates or outdoor huts. At weaning, indoor- and outdoor-born pigs were allotted randomly to treatments arranged in a 2 x 2 factorial design with two birth (indoor vs. outdoor) and rearing (indoor vs. outdoor) environments. Pigs housed indoors were on concrete-slatted flooring (1.2 m2/pig), and pigs housed outdoors were on an alfalfa pasture (212 m2/pig). Body weight data were collected. Muscle samples were removed within 1 h postmortem from the longissimus (LM) and semimembranosus (SM) muscles. Muscle samples were stained histochemically to identify type I, IIA, and IIB/X muscle fibers. Boneless loins were collected from the left side of each carcass and aged for 14 d. Objective and subjective color measurements were taken on the longissimus muscle at the 10th rib on d 14 postmortem. Loin chops were evaluated for sensory attributes, shear force, and retail display features. Pigs born outdoors were heavier and had a greater ADG at most growth intervals postweaning (d 28, 56, and 112; P < 0.05) than pigs born indoors. Pigs reared outdoors were heavier (P = 0.02) at d 140 (120.1 vs. 112.9 +/- 4.9 kg), and had higher (P = 0.01) ADG (2.2 vs. 1.9 kg/d) and gain:feed ratios (0.41 vs. 0.37) than did pigs reared indoors. Birth x rearing environment interactions were not significant (P > 0.10) for most measures. Carcass and meat quality measures did not differ (P > 0.05) among treatment groups, but loin chops from outdoor born or reared pigs had higher (P < 0.05) a* values than chops from pigs born or reared indoors. The LM muscle of pigs born outdoors had a higher (P < 0.01) percentage of type I, and a lower (P < 0.05) percentage of type IIA fibers than did pigs born indoors. Pigs reared outdoors had a higher (P < 0.01) percentage of IIA fibers and a lower (P < 0.05) percentage of IIB/X fibers than did pigs reared indoors for the LM and SM muscles. Outdoor production systems may influence growth, pork color, and muscle fiber types.

Effects of growth implants on consumer perceptions of meat tenderness in beef steers.

Anabolic steroid implants are routinely used to increase growth performance and profitability; however, there are concerns that the use of implants, particularly those containing trenbolone acetate, may have detrimental effects on carcass quality and beef tenderness. Thus, the objectives of the current study were to determine the effects of various commonly used implant regimens on shear force values, sensory properties, and consumer satisfaction of beef top loin steaks from cattle of Bos indicus influence. Cattle were supplied by producers that agreed to provide sire and dam information in exchange for carcass and sensory data. Steers (n = 2,748) were assigned randomly to one of three implant treatments (12/sire; four steers from each sire were placed into each treatment group): 1) unimplanted controls (n = 1,368); 2) Synovex-S followed by another Synovex-S (n = 660); or 3) Synovex-S followed by Revalor-S (n = 720). Steaks sampled after 3, 7, and 14 d of aging indicated that unimplanted cattle had lower (P < 0.05) Warner-Bratzler Shear force values than those from implanted animals. No differences (P > 0.05) in shear force values were found between the two treatments or the control groups for steaks sampled following a 21-d aging period. Steaks from implanted animals sampled after 3, 7, and 14 d aging were rated lower (P < 0.05) for initial and sustained trained sensory panel tenderness scores. Consumers failed to detect any differences in steak samples related to implant treatment after 7 and 14 d of aging. Consumer education level and family income did not affect overall acceptability (P > 0.10 and 0.18, respectively) or tenderness acceptability (P > 0.11 and 0.68, respectively); however, consumers with postgraduate degrees recorded lower (P < 0.05) overall quality, beef flavor, juiciness, and tenderness scores than consumers in all other education classifications. Additionally, family income had no effect on overall quality (P > 0.21), beef flavor (P > 0.28), juiciness (P > 0.58), or tenderness (P > 0.45) scores. Results indicate that using a moderate implant program in Bos indicus-influenced cattle has no detrimental effects on beef tenderness and consumer acceptability.

Impact of spontaneous exercise on performance, meat quality, and muscle fiber characteristics of growing/finishing pigs.

The objective of this experiment was to determine if increased space and exercise for finisher pigs (0.90 vs 9.45 m2/pig) affects performance, meat quality, or muscle fiber characteristics. Newsham barrows (n = 32, 4 pens/treatment) were placed in one of two space allocations: control space allowance (CONT) or in a long pen with increased space allowance (10x). Pigs were weighed every 28 d and feed intake/pen was calculated. Pigs were filmed for behavioral analysis on d 70 and 100 using video recorders to determine walking distances over a 24-h period. After a 5-h transport and 2-h rest period, pigs (approximately 115 kg) were slaughtered on the same day at a commercial facility. Muscle samples were obtained from the longissimus lumborum (LL) and semimembranosus (SM) muscles within 1 h postmortem for muscle fiber typing. Backfat thickness and pH decline were measured on the left side of each carcass. After 24-h chilling, a boneless loin was collected from each pig and stored at 2 degrees C until analyzed. On d 14 postmortem, loins were cut at the 10th rib for color evaluations, and chops were cut for Warner-Bratzler shear (WBS) force and sensory analysis. Histochemical staining methods were used for the detection of type I, IIA, and IIB/X muscle fiber types. There were no significant differences (P > 0.10) in live weight, ADG, ADFI, or G:F ratio of the two experimental groups evaluated. Pigs finished in 10x pens walked a greater (P < 0.01) distance over a 24-h period than pigs finished in the CONT pens. Pigs finished in the lOx pens were fatter (P < 0.05) at the last lumbar vertebra than pigs finished in the CONT pens, but no significant differences were found in loineye area, loin color, marbling scores, WBS, sensory panel scores, retail display measures, or muscle fiber type percentages. Expanded space allowance to increase exercise resulted in no improvements in pig performance, pork loin measures, or muscle characteristics.

Diverse birth and rearing environment effects on pig growth and meat quality.

Birth and rearing conditions were evaluated for their effects on pig growth, body composition, and pork quality using 48 barrows during the spring and summer months. Pigs were either farrowed in indoor crates or outdoor huts. At weaning, indoor-born and outdoor-born pigs were randomly allotted to indoor or outdoor treatments for growing/finishing. Body weight data were collected. Pigs were transported 5 h to a commercial processing plant, allowed 2 h of rest, and then processed as a group under commercial conditions. Boneless loins were collected from the left side of each carcass and aged for 14 d. Objective and subjective color measurements were taken on the longissimus muscle at the 10th rib on d 14 postmortem. Loin chops were evaluated for sensory attributes, shear force, and retail display features. Pigs born outdoors were heavier and had greater ADG at all growth intervals after weaning (d 28, 56, 112, and final weight, P < 0. 05) than pigs born indoors. Outdoor-born pigs had heavier carcass weights (91.2 vs 81.3+/-3.4 kg, P < 0.001), larger loineye areas (54.6 vs 49.7+/-0.2 cm , P < 0.05), and higher pork flavor intensity scores (6.5 vs 6.1+/-0.10, P < 0.01) than indoor-born pigs. Birth x rearing environment interactions were not significant for most measures. Backfat measurements at the last rib were greater (3.2 vs 2.8+/-0.05 cm, P < 0.05) for the pigs reared outdoors than for the pigs reared indoors. Pigs finished outdoors had more reddish pink color scores, lower shear force values, and lower L* values, indicating darker-colored pork, compared with pigs finished indoors (P < 0.05). Pig birth environment played a significant role in improving growth rates of outdoor-born pigs and increasing pork flavor intensity scores of loin chops from pigs born outdoors. Finishing pigs outdoors may improve pork color and tenderness but also may increase backfat thickness when they are fed conventional diets.

Alternative housing systems for pigs: influences on growth, composition, and pork quality.

Effects of pig birth (first 3-wk period) and rearing environments on growth and muscle quality characteristics of loins were evaluated in three experiments over seasons in west Texas and central Missouri. Housing systems included indoor slatted-floor buildings, indoor deep-bedded buildings, outdoor housing on dirt, and outdoor housing on alfalfa pasture. Experiments were conducted during the growing/finishing phases and pigs were slaughtered at the same age. Loins were collected, vacuum-packaged, and stored for 14 d at 2 degrees C. Pigs born and finished in an outdoor environment during the summer months (Exp. 1) had a greater ADG (0.92 vs 0.82+/-0.06 kg/d, P < 0.05) and had heavier carcass weights (87.9 vs 78.4+/-2.4 kg, P < 0.05) than pigs born and finished in an indoor environment with a slatted-floor finishing building. Carcasses from the outdoor-reared group measured a larger (P < 0.05) loineye area and were fatter (P < 0.01) at the first rib, last rib, and last lumbar vertebra measurements than carcasses from the indoor-reared group. Loin chops from outdoor-reared pigs had darker color scores in the retail display case throughout the 4-d period, measured lower L* values on d 1, and had more discoloration and browning on d 4 than loin chops from the indoor-reared group. During the winter months (Exp. 2), no difference was detected in ADG, carcass measurements, sensory characteristics, or shear force values from indoor-born pigs placed in either an outdoor or indoor finishing environment. Pigs finished on deep bedding (Exp. 3) had heavier carcass weights and more backfat (P < 0.01) than pigs finished on slats, but no differences were detected in sensory panel or shear force results. Overall, carcass measurements, pH, drip loss, sensory panel, and shear force values were similar among the groups finished in different housing systems. Outdoor or deep-bedded systems may increase growth rates of pigs if suitable land area and resources are available, but pork quality of loins will be similar for pigs finished in either conventional or alternative systems.

Effects of the transportation of beef cattle from the feedyard to the packing plant on prevalence levels of Escherichia coli O157 and Salmonella spp.

Two hundred steers and heifers from a large feedyard (65,000-head capacity) were used to determine the prevalence levels of enterohemorrhagic Escherichia coli O157 (EHEC O157) and Salmonella spp. prior to and after shipping to a commercial packing facility. Two samples, a ventral midline hide swab and a fecal sample, were aseptically collected from each animal 2 weeks prior to the date of transportation and at the packing plant immediately after exsanguination. Samples were collected from all trailers (n = 46) before animals were loaded for transport to the packing facility. The average prevalence levels of EHEC O157 on hides (18%) and in feces (9.5%) at the feedyard decreased (P > 0.05) at the packing plant to 4.5 and 5.5%, respectively. The average prevalence levels of Salmonella spp. on hides (6%) and in feces (18%) at the feedyard increased to 89 and 46%, respectively, upon arrival at the packing plant. Average prevalence levels for EHEC O157 and Salmonella spp. on the trailers were 5.43 and 59%, respectively. The results of this study demonstrate that transportation may be a potential stressor for cattle, as evidenced by the increased shedding of Salmonella spp.