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Context. Genomic-based technologies are allowing commercial beef producers to predict the genetic merit of individual animals of unknown pedigree with increased ease and accuracy. Genomic selection tools that can accurately predict the feedlot and carcass performance of steers have the potential to improve profitability for the beef supply chain. Aims. To validate the ability of the Angus SteerSELECT genomic product to predict differences in performance of Australian Angus steers, in terms of carcass weight, marbling score, ossification score and carcass value, using a short-fed (100 days) or long-fed (270 days) finishing protocol at a commercial feedlot. Methods. A reference population of 2763 Australian Angus steers was used to generate genomic prediction equations for three carcass traits, namely, carcass weight, marbling score and ossification. The accuracy and bias of genomic predictions of breeding values were then evaluated using a validation population of 522 Angus steers, either short- or long-fed at a commercial feedlot, by comparing breeding values to measured phenotypes. The potential economic benefits for feedlot operators when using Angus SteerSELECT were estimated on the basis of the ability of the tool to predict the carcass value of steers in the validation population. Key results. The accuracy of genomic predictions of breeding values for carcass weight, marbling score and ossification score were 0.752, 0.723 and 0.734 respectively. When steers were ranked in quartiles for predicted carcass value, calculated using genomic predictions of breeding values for carcass weight and marbling score, the least-square mean carcass value for steers in each quartile, from bottom 25% predicted performers to top 25% predicted performers, were estimated at A$1794, A$1977, A$2021 and A$2148 for short-fed steers and A$3546, A$3780, A$3864 and A $4258 for long-fed steers. Differences in the carcass value least-squares mean between the bottom and top quartile were highly significant (P < 0.001) for both short-fed and long-fed steers. Conclusions. Genomic prediction equations used in Angus SteerSELECT can predict differences in carcass weight, marbling score, ossification score and carcass value in both short-fed and long-fed Australian Angus steers. Implications. Genomic selection tools that can predict differences in performance, in terms of growth and carcass characteristics, of commercial feedlot cattle have the potential to significantly increase profitability for the beef supply chain by improving the quality and consistency of the beef products they produce. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify barley grain characteristics measured by laboratory procedures that could be used to predict barley energy content for finishing beef steers. Twenty-eight different barley genotypes were evaluated including 18 cultivars and 10 experimental lines. Laboratory analysis of barley samples included bulk density, particle size, N, ADF, starch, and ISDMD (in situ DM disappearance after 3 h of ruminal incubation). Animal performance data (BW, DMI, ADG, steer NEm, and NEg requirements) were collected from 26 feedlot experiments conducted in Montana and Idaho during a 10-yr period and were used to estimate barley NEm and NEg content. A total of 80 experimental units were available with each experimental unit being a diet mean from an individual feedlot experiment. Fifty-eight of the 80 experimental units were randomly selected and used in the development data set and the remaining 22 experimental units were used in the validation data set. Forward, backward, and stepwise selection methods were used to identify variables to be included in regression equations for NEm using PROC REG of SAS. Barley samples in the model development data set represented a wide range in concentrations (DM basis): N (1.6% to 2.8%), ISDMD (25.7% to 58.7%), ADF (3.6% to 8.0%), starch (44.1% to 62.4%), particle size (1,100 to 2,814 µm), and bulk density (50.8 to 69.4 kg/hL). The barley grain characteristics of particle size, ISDMD, starch, and ADF were the most important variables in six successful models (R 2 = 0.48 to 0.60; P = 0.001). The six prediction equations gave mean predicted values for NEm ranging from 1.99 to 2.05 Mcal/kg (average 2.04 Mcal/kg; 0.45% CV). The mean actual NEm values from animal performance trials ranged from 1.75 to 2.48 Mcal/kg (average 2.03 Mcal/kg; 6.5% CV). The mean bias or difference in predicted vs. actual values ranged from −0.001 to 0.005 Mcal/kg. Barley NEg values calculated from animal performance ranged from 1.13 to 1.78 Mcal/kg (average 1.39 Mcal/kg; 8.4% CV). Average predicted barley NEm and NEg were 0.02 and 0.01 Mcal/kg less, respectively, than the 2.06 Mcal/kg NEm and 1.40 Mcal/kg NEg reported by NRC. Barley NE can be predicted from simple laboratory procedures which will aid plant breeders developing new feed varieties and nutritionists formulating finishing rations for beef cattle. [ABSTRACT FROM AUTHOR]

Our objective was to determine the effects of dry and wet conditions during the preweaning on subsequent feedlot performance and carcass characteristics of beef cattle. Steers (n = 7,432) and heifers (n = 2,361) finished in 16 feedlots in southwestern Iowa through the Tri-County Steer Carcass Futurity Cooperative were used for a retrospective analysis. Cattle originated in the Midwest (Iowa, Missouri, Indiana, Illinois, and Minnesota) and were born in February, March, or April of 2002 through 2013. Feedlot performance and carcass composition data were obtained for each animal. Palmer Drought Severity Index (PDSI) values were obtained for each animal's preweaning environment on a monthly basis. Mean PDSI values were used to classify conditions as dry (≤−2.0), normal (>−2.0 and <2.0), or wet (≥2.0) for the cool (April and May), warm (June through August), and combined (April through August) forage growing seasons preweaning. Mixed models were used to evaluate the effects of PDSI class on subsequent performance. Calf sex, date of birth (as day of year), year, and feedlot were also included as fixed effects. When considering PDSI class during the cool season, cattle from normal and wet classes had a greater feedlot delivery BW (P < 0.0001) than dry. Dry and normal classes had greater (P ≤ 0.02) delivery BW than wet during the warm and combined seasons, however. For the cool season, average daily gain was greater (P < 0.0001) for the dry class than normal and wet. Cattle from the normal class for the cool season had greater (P = 0.001) final BW than wet, but the wet class had the greatest (P < 0.04) and dry class had the lowest (P < 0.01) final BW during the warm season. During the cool season, HCW was greater (P < 0.007) for the normal than wet class, although HCW was greater (P ≤ 0.02) for wet compared with dry and normal during the warm season. Calculated yield grade was lower (P ≤ 0.006) for the normal class during the cool season compared with dry and wet. For both the warm and combined seasons, the dry class had lower (P ≤ 0.004) calculated yield grade compared with normal and wet. Carcasses from cattle that experienced normal or wet warm seasons had greater (P ≤ 0.0005) marbling scores than dry, and normal had greater (P = 0.0009) marbling score than dry for the combined seasons. In conclusion, these data indicate that both dry and wet conditions during the preweaning phase may impact ultimate feedlot performance and carcass composition. [ABSTRACT FROM AUTHOR]

Objetivou-se avaliar o efeito do nível de concentrado e dos sais de cálcio de ácidos graxos (SCAG) sobre o desempenho e qualidade da carne de novilhos terminados em confinamento. Sessenta novilhos Nelore e cruza Nelore foram divididos em quatro grupos e confinados por um período de 85 dias com as seguintes dietas: (BC) 46,7% de concentrado; (BC-SCAG) dieta BC acrescida de 3% de SCAG; (AC) dieta contendo 76,6% de concentrado e (AC-SCAG) dieta AC com 3% de SCAG. O nível de concentrado não influenciou o ganho médio diário, a espessura de gordura subcutânea e a área de olho de lombo, mas as dietas AC aumentaram o peso (P=0,0011) e o rendimento (PThe objective of this research was to evaluate the effects of concentrate level and calcium salts of fatty acids (SCAG) on performance and meat quality of feedlot finished steers. Sixty Nellore and Nellore crossbred steers were distributed in four groups and fed for 85 days with one of the following diets: BC) diet containing 46.7% of concentrate; (BC-SCAG) LC diet plus 3% of SCAG; (AC) diet containing 76.6% of concentrate and (AC- SCAG) HC diet plus 3% of SCAG. Concentrate level did not affected average daily gain, subcutaneous fat thickness and ribeye area, but AC diets increased carcass weight (P=0.0011), dressing percentage (P

Objetivou-se com este trabalho avaliar os efeitos do milho grão seco ou úmido e dos sais de cálcio de ácidos graxos no desempenho e nas características de carcaça de novilhos Nelore confinados na fase de terminação. Quarenta e oito animais com peso inicial de 431 ± 29,8 kg foram alimentados durante 70 dias com uma das seguintes dietas: MGS - dieta basal composta de silagem de milho (40%), milho grão seco (48,4%), farelo de soja (7,6%), uréia, sufato de amônia, cloreto de potássio, sal mineral, rúmen tamponante e rumensina (4%); MGU - dieta basal, com substituição do MGS por milho grão úmido; MGS-SCAG - dieta basal contendo 45% de MGS e 4% de sais de cálcio de ácidos graxos; MGU-SCAG - dieta basal com 45% de milho grão úmido e 4% de sais de cálcio de ácidos graxos. O ganho médio diário não foi influenciado pelo tipo de grão de milho, no entanto, a ingestão de MS pelos animais da dieta MGU foi menor que naqueles alimentados com a dieta MGS e resultou em maior eficiência alimentar para a dieta MGU. O maior número de protozoários ciliados ruminais foi observado nos animais alimentados com a dieta MGU. O rendimento de carcaça, a gordura renal pélvica e inguinal e a espessura de gordura subcutânea foram maiores nos animais alimentados com a dieta MGS. O ganho de peso médio diário também não diferiu entre os animais tratados ou não com SCAG, no entanto, a ingestão de MS foi maior nos animais alimentados com a dieta SCAG. Não houve influência sobre a eficiência alimentar. O número de protozoários ruminais foi menor nos animais alimentados com as dietas contendo SCAG, no entanto, as características de carcaça não foram influenciadas por essa dieta.The aim of this work was to evaluate the effects of dry corn grain or high moisture corn and calcium salts of fat acids on the performance and carcass traits of feedlot fed Nellore steers on finishing phase. Forty eight animals with 431 ± 29.8kg of initial mean body weight were fed during 70 days, with one of the four diets: MGS - basal diet containing corn silage (40%), dry corn grain (48.4%), soybean meal (7.6%), urea, amonium sulphate, mineral salt, limestone and monensin (4%); MGU - basal diet with high moisture corn replacing MGS; MGS-SCAG basal diet with 45% of MGU and 4% of calcium salts of fatty acids; MGU-SCAG - basal diet with 45% of MGS and 4% of calcium salts of fatty acids. The average daily gain was not affected by grain type. However, dry matter intake of animals of MGU treatment was smaller than MGS treatment, with a greater feed efficiency for MGU treatment. A greater number of ruminal ciliate protozoa was found in MGU treatments. Dressing percentage, renal, pelvic and inguinal fat and backfat thickness were greater in animals fed MGS diet. Average daily gain was not different between animals fed with or without SCAG, although, dry matter intake was greater in diets with SCAG, with no effect on feed efficiency. Protozoa number was smaller in diets containing SCAG and carcass traits were not affected by SCAG.

Sixteen Holstein beef cattles, weighing 270 kg and 5-6 months age, were assigned to one of two treatments (8 animal per treatment) in a completely randomized design. All animals in both groups fed with basal diet containig; concentrated feed, barley, cottonseed meal and straw. Live yeast culture (Saccharomyces cerevisiae, 1,4 X 108 cfu/g) incorporated into yeast group rations 50 g/d. The study lasted 135 days. At the beginning of the trial, animals were adapted to the basal diet over a 15- day period. Feed consumption was measured daily, while body weight and body weight gain was measured monthly. At the end of the study, four animals from each groups were slaughtered and the hot carcass yield was determined. Rumen contents were collected on days 45th and 90th analyzed for pH, volatile fatty acids and ammonia-N (NH3-N). Dietary treatment had no effect (p>0,05) on DMI (Dry matter intake), FCR (Feed conversion ratio), final live body weight, and ADG (Avarage daily gain) (p>0,05). Carcass yield was significantly (p 0,05) increased by dietary inclusion of yeast so that carcasss yield was 50,65% and 52,75% in control and yeast group respectively, in the yeast group. There was also no significant (p>0,05) differences for rumen volatile fatty acids (VFA) and ammonia-N between each groups. However, rumen pH was lower (p<0,05) for the yeast group. No differences (p>0,05) between groups were observed regarding blood parameters. [ABSTRACT FROM AUTHOR]

Feedlot producers often exceed NRC recommendations for vitamin A and D supplementation; however, increased concentrations of these vitamins have been shown to limit adipocyte differentiation in vitro. A feedlot trial was conducted using 168 Angus crossbred steers (BW = 284 ± 0.4 kg) allotted to 24 pens. The experiment had a 2 × 2 factorial arrangement of treatments: no supplemental vitamin A or D (NAND), 3,750 IU vitamin A/kg dietary DM with no supplemental vitamin D (SAND), no supplemental vitamin A and 1,860 IU vitamin D/kg dietary DM (NASD), and 3,750 IU and 1,860 IU vitamin A and D/ kg dietary DM (SASD), respectively. Serum, liver, and intramuscular and subcutaneous adipose tissue retinol concentrations were decreased in (P < 0.001) in cattle fed the no supplemental vitamin A diets (NAND and NASD combined) compared with those consuming supplemental vitamin A (SAND and SASD combined) diets. In addition, intramuscular retinol concentration was 38% less than in the subcutaneous depot. Serum 25(OH)D3 concentrations were reduced (JP < 0.001 ) during the first 70 d when cattle were fed no supplemental vitamin D diets (NAND and SAND combined); however, liver 25(OH)D3 concentrations remained unchanged (P > 0.10) through d 184. Serum and liver 25(OH)D3 concentrations increased (P < 0.001) with vitamin D supplementation (NASD and SASD combined). The DMI, ADG, G:F, and morbidity were not affected (P > 0.10) by dietary concentration of vitamin A or D. There were vitamin A and D interactions (P < 0.03) for backfat thickness and USDA Yield grade. Cattle fed the NAND diet had greater (P < 0.03) Yield grades than other treatments because of greater (P < 0.005) 12th rib backfat thickness in NAND steers than the NASD and SAND steers. Vitamin D concentrations were attenuated and minimal carcass adiposity responses to vitamin D supplementation were observed. Feeding a diet without supplemental vitamin A increased (P < 0.05) Quality grades and marbling scores and tended (P = 0.06) to increase ether extractable lipid of the LM. As retinol and 25(OH)D3 concentrations in feedlot cattle declined as a result of a lack of dietary supplementation, adipose accretion increased, resulting in elevated Quality and Yield grades. Withdrawal of supplemental vitamin A, D, or both from the finishing diet of feedlot beef cattle had minimal impact carcass composition. [ABSTRACT FROM AUTHOR]

Crossbred yearling steers (n = 80; 406 ± 2.7 kg of BW) were used to evaluate the effects of S concentration in dried distillers grains with solubles (DDGS) on growth performance, carcass characteristics, and ruminal concentrations of CH4 and H2S in finishing steers fed diets based on steam-flaked corn (SFC) or dry-rolled corn (DRC) and containing 30% DDGS (DM basis) with moderate S (0.42% S, MS) or high S (0.65% S, HS). Treatments consisted of SFC diets containing MS (SFC-MS), SFC diets containing HS (SFC-HS), DRC diets containing MS (DRC-MS), or DRC diets containing HS (DRC-HS). High S was achieved by adding H2SO4 to DDGS. Ruminal gas samples were analyzed for concentrations of H2S and CH4. Steers were fed once daily in quantities that resulted in traces of residual feed in the bunk the following day for 140 d. No interactions (P ≥ 0.15) between dietary S concentration and grain processing were observed with respect to growth performance or carcass characteristics. Steers fed HS diets had 8.9% less DMI (P < 0.001) and 12.9% less ADG (P = 0.006) than steers fed diets with MS, but S concentration had no effect on G:F (P = 0.25). Cattle fed HS yielded 4.3% lighter HCW (P = 0.006) and had 16.2% less KPH (P = 0.009) than steers fed MS. Steers fed HS had decreased (P = 0.04) yield grades compared with steers fed MS. No differences were observed among treatments with respect to dressing percentage, liver abscesses, 12th-rib fat thickness, LM area, or USDA quality grades (P = 0.18). Steers fed SFC had less DMI (P < 0.001) than steers fed DRC. Grain processing had no effect (P > 0.05) on G:F or carcass characteristics. Cattle fed HS had greater (P < 0.001) ruminal concentrations of H2S than cattle fed MS. Hydrogen sulfide concentration was inversely related (P ≤ 0.01) to ADG (r = -0.58) and DMI (r = -0.67) in cattle fed SFC, and to DMI (r = -0.40) in cattle fed DRC. Feeding DDGS that are high in dietary S may decrease the DMI of beef steers and compromise the growth performance and carcass characteristics of feedlot cattle. [ABSTRACT FROM AUTHOR]

Our objective was to compare the effects of feeding steam-flaked, high-oil corn with normal steam-flaked corn to which yellow grease was added to equalize dietary fat on performance and carcass characteristics of finishing beef steers, and palatability, retail case life, and fatty acid composition of strip loins. Angus steers. (n = 120; initial BW = 288 kg) were allotted to dietary treatments consisting of 1) normal mill-run, steam-flaked corn plus added fat (NMR) or 2) highoil, steam-flaked corn (HOC) and assigned randomly to pens (12 pens/treatment with 5 steers/pen). Performance (ADG, DM1, and G:F) was measured over time, and cattle were shipped to a commercial abattoir for collection of carcass data after 165 d on feed. Carcass data were collected at 48 h postmortem on all carcasses, and 2 carcasses from each pen were selected randomly for collection of strip loins (IMPS #180A). At 14 ci postmortem, 4 steaks (2.54 cm thick) were renioveci for retail display, trained sensory panel analysis, Warner-Bratzler shear force determination, and fatty acid analysis. Daily BW gain was greater (P = 0.03) and G:F was increased 8.4% (P = 0.01) for steers fed NMR compared with HOC, but DM1 was not affected (P> 0.10) by treatment. No treatment differences were observed (P> 0.10) for HCW, 12th-rib fat, KPH, and yield grade. Marbling scores were greater (P = 0.01) for NMR than for HOC, and LM area tended (P = 0.07) to be greater in NMR than in HOC carcasses. The proportion of carcasses grading USDA Choice did not differ (P = 0.77) between treatments, but a greater (P = 0.04) proportion of carcasses graded in the upper two-thirds of Choice for NMR vs. HOC. Trained sensory panel traits and Warner-Bratzler shear force values did not differ between treatments (P > 0.10), and no differences (P > 0.10) were detected for purge loss or fatty acid composition. Overall, ADG and G:F were less and marbling score was decreased, but there were no differences between treatments in beef palatability, retail case life, or concentrations of fatty acids in strip loins. [ABSTRACT FROM AUTHOR]

The objective of this research was to evaluate the effects of concentrate level and calcium salts of fatty acids (SCAG) on performance and meat quality of feedlot finished steers. Sixty Nellore and Nellore crossbred steers were distributed in four groups and fed for 85 days with one of the following diets: BC) diet containing 46.7% of concentrate; (BC-SCAG) LC diet plus 3% of SCAG; (AC) diet containing 76.6% of concentrate and (AC- SCAG) HC diet plus 3% of SCAG. Concentrate level did not affected average daily gain, subcutaneous fat thickness and ribeye area, but AC diets increased carcass weight (P=0.0011), dressing percentage (P<0.0001) and shear force (P=0.0438). SCAG increased average daily gain in AC (P=0.0311) but not in BC diets. Animals fed with SCAG diets showed greater carcass weight (P=0.0133) and dressing percentage (P=0.0160) with no differences on fat thickness, ribeye area and shear force. High concentrate diets and SCAG improved quantitative carcass traits (weight and dressing percentage) of finishing cattle and can be used as alternative to improve the efficiency of the production system. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of winter growing program on subsequent finishing performance, carcass merit, and body composition of beef steers. Four steers were slaughtered to determine initial body composition. Remaining steers (n = 256) were blocked by BW and randomly allotted to 1 of 4 treatment groups: 1) ad libitum fed a high-concentrate diet (CF), 2) grazed on wheat pasture (WP), 3) fed a sorghum silage-based diet (SF), or 4) program fed a high-concentrate diet (PF). Steers in the WP, SF, and PF groups were managed to achieve approximately equal rates of BW gain. After the growing phase (112 d), 6 steers were randomly selected from the WP, SF, and PF treatments for determination of body composition. Remaining steers were adapted to a high-concentrate diet for finishing and slaughtered at 1.27 cm of 12th-rib fat. Six steers from each treatment were used to determine carcass, offal, and empty body composition; During the growing phase, WP, SF, and PF steers gained 1.15, 1.10, and 1.18 kg/d, respectively, and ME intake did not differ (P = 0.50) among treatments. Program-fed and SF steers had greater (P < 0.05) offal and empty body fat content than WP steers. Gain in offal and empty body fat was greatest (P < 0.05) for PF steers, intermediate for SF steers, and least for VIP steers. During the finishing phase (123, 104, 104, 196 d for WP, SF, PF, and CF, respectively) DM1 was greater (P < 0.01) for SF steers (10.9 kg/d) than for PF steers (10.1 kg/d); WP steers were intermediate (10.4 kg/d). Daily BW gain was greatest (P < 0.05) for SF steers (2.02 kg/d), intermediate for PF steers (1.85 kg/d), and least for WP and CF steers (1.64 and 1.63 kg/d, respectively). Accretion (kg/d) of carcass and empty body mass was less (P < 0.05) for WP and CF steers compared with PF and SF steers. Calf-fed steers had greater (P < 0.05) fat content of offal than SF and PF steers; WP steers were intermediate. Gain in empty body and carcass energy (Mcal/d) was greater (P < 0.05) for PF steers than CF steers with SF and WP steers being intermediate. At slaughter, SF steers had reduced (P < 0.01) yield grades and greater marbling scores compared with CF and WP steers; PF steers were intermediate. In conclusion, growing programs that increase fat composition of feeder calves did not negatively affect subsequent finishing performance. Finishing steers as calves may reduce retained energy of carcass tissues and increase internal fat during highgrain feeding compared with steers that previously underwent a growing program. [ABSTRACT FROM AUTHOR]

Crossbred, spring-calving cows (yr 1, n = 136; yr 2, n = 113; yr 3, n = 113) were used in a 3-yr experiment to evaluate the influence of supplemental protein prepartum and grazing subirrigated meadow postpartum on pregnancy rates and calf feedlot performance. A 2 × 2 factorial arrangement of treatments was used in a switchback design. From December 1 to February 28, cows grazed dormant upland range in 8 pastures (32 ± 2 ha each). The equivalent of 0.45 kg of supplement/cow per d (42% CP) was provided to half of the cows on a pasture basis 3 d/wk. For 30 d before the beginning of breeding (May 1 to May 31), half of the cows grazed a common subirrigated meadow (58 ha), and the remainder was fed grass hay in a drylot. Cow BW and BCS were monitored throughout the year, and steer calf performance was determined until slaughter. Feeding supplement prepartum improved (P = 0.01 to P < 0.001) BCS precalving (5.1 vs. 4.7) and prebreeding (5.1 vs. 4.9) and increased (P = 0.02) the percentage of live calves at weaning (98.5 vs. 93.6%) but did not affect (P = 0.46) pregnancy rate (93 vs. 90%). Calves born to dams fed supplement prepartum had similar (P = 0.29) birth weight (37 vs. 36 kg) but greater (P = 0.02) weaning weight (218 vs. 211 kg). However, steer feedlot DMI (8.53 vs. 8.48 kg), ADG (1.6 vs. 1.6 kg), and carcass weight (369 vs. 363 kg) were not affected (P = 0.23 to P = 0.89) by prepartum supplementation. Allowing cows to graze subirrigated meadow postpartum improved (P < 0.001) BCS prebreeding (5.2 vs. 4.9) but did not affect (P = 0.88) pregnancy rate (92 vs. 91%). Allowing cows to graze subirrigated meadow increased (P = 0.01) calf weaning weight (218 vs. 211 kg) but not (P = 0.62 to P = 0.91) feedlot DMI (8.4 vs. 8.3 kg), ADG (1.6 vs. 1.6 kg), or carcass weight (363 vs. 362 kg) of their steer calves. Increased percentage of live calves at weaning as a result of feeding supplemental protein increased net returns at weaning and after finishing in the feedlot. Net returns were increased by allowing cows to graze subirrigated meadow postpartum regardless of whether calves were marketed at weaning or after finishing in the feedlot. [ABSTRACT FROM AUTHOR]

Forty Angus-cross steers were used to evaluate 5 beef cattle management regimens for their effect on growth performance, carcass characteristics, and cost of production. A 98-d growing phase was incorporated using grass silage with or without growth promotants (trenbolone acetate + estradiol implants, and monensin in the feed) or soybean meal. Dietary treatments in the finishing phase were developed, with or without addition of the same growth promotants, based on exclusive feeding of forages with minimal supplementation or the feeding of barley-based diets. Overall, ADG for animals treated with growth promotants or fed supplemented diets (soybean meal and barley) was increased (P < 0.01) by 25 and 21%, respectively, compared with steers reared on grass silage alone and not treated with growth promotants. Except for HCW (P < 0.01), the use of growth promotants did not affect carcass measurements. Increasing the proportion of barley in the diet of steers finished on forage produced a heavier HCW (P < 0.01) and a greater (P < 0.01) quality grade. Because of their lower HCW and quality grade, cattle targeted to a forage-fed, nonimplanted beef market would need to garner a 16% premium to be economically competitive with cattle finished conventionally. [ABSTRACT FROM AUTHOR]

This review assessed the relationships between dietary energy density and animal performance in an effort to evaluate a possible upper limit for energy density in finishing diets for cattle. Data were combined from 49 experiments (69 trials; 243 treatment observations) in which the dietary ME concentration (Mcal/kg of DM) was varied by level of concentrate, grain source, grain processing, and level of supplemental fat. Dietary concentrations of ME were determined using 1) NRC values of ME from diet ingredients; or 2) values derived from the literature, in which ingredient ME had been calculated from animal performance. Procedures for pooling data from multiple studies were used. The dependent variable was fit to a model that included a random slope and intercept clustered by trial. Trial-adjusted dependent variables (animal performance and carcass characteristics) were regressed on the independent variable (dietary ME concentration). Models were fit to cubic equations, and then reduced from cubic to quadratic to linear equations when the cubic and quadratic terms were not significant at P > 0.10. When NRC values were used, the relationship of DMI (% of BW) to dietary ME was linear (DMI decreased as ME increased; R2 = 0.631). However, the slope of ME intake (Mcal/kg of BW0.75) vs. dietary ME content did not differ (P > 0.25) from zero, supporting the concept that ruminants on high-grain diets (2.7 to 3.3 Mcal of ME/kg of DM) eat to maintain constant energy intake. Quadratic relationships were observed (P < 0.05) when ADG and G:F vs. dietary ME concentration were analyzed. Gain:feed was maximized with 3.46 (NRC) to 3.65 (calculated) Mcal/kg of ME from the total diet, 2.99 (NRC) to 3.40 (calculated) Mcal/kg of ME from grain, and 0.43 (NRC) to 0.53 (calculated) Mcal/kg of ME from supplemental fat. Most relationships of carcass traits to dietary ME were not significant (P > 0.10). Increased 12th-rib fat at greater ME and increasing KPH suggests greater fat deposition with increasing caloric density. Assuming that NRC ME values for ingredients commonly used in finishing diets are correct, the upper caloric limit for maximizing ADG and G:F was 3.16 and 3.45 Mcal/kg of DM, respectively. Reaching the upper caloric limit for G:F would require most grains to be processed or fed in high-moisture form. Whether maximizing G:F results in the most desirable carcass composition and yield of retail cuts should be determined. [ABSTRACT FROM AUTHOR]

Presents abstracts of several studies about energy and nitrogen in beef. "Blood Ketone Levels of Young Postpartum Range Cows Increased After Supplementation Ceased," by R. L. Endecott, C. M. Black, K. A. Notah, and M. K. Petersen; "A Comparison of Whole Animal Energy Expenditure by Angus, Holstein, and Wagyu Heifers," by K. A. Ross, C. T. Gaskins, J. J. Michal, D. H. Keisler, and K. A. Johnson; "Effects of Energy Supply on Methionine Utilization by Growing Steers," by G. F. Schroeder, E. C. Titgemeyer, M. S. Awawdeh, and D. P. Gnad; "Evaluation of Soybean Hulls and Protein Sources of Varying Degradability on Steer Performance in Feedlot Receiving Diets," by C. J. Mueller, R. H. Pritchard, and D. L. Boggs.

Presents abstracts of several studies about energy and nitrogen in beef. "Blood Ketone Levels of Young Postpartum Range Cows Increased After Supplementation Ceased," by R. L. Endecott, C. M. Black, K. A. Notah, and M. K. Petersen; "A Comparison of Whole Animal Energy Expenditure by Angus, Holstein, and Wagyu Heifers," by K. A. Ross, C. T. Gaskins, J. J. Michal, D. H. Keisler, and K. A. Johnson; "Effects of Energy Supply on Methionine Utilization by Growing Steers," by G. F. Schroeder, E. C. Titgemeyer, M. S. Awawdeh, and D. P. Gnad; "Evaluation of Soybean Hulls and Protein Sources of Varying Degradability on Steer Performance in Feedlot Receiving Diets," by C. J. Mueller, R. H. Pritchard, and D. L. Boggs.

Presents abstracts of several studies about energy and nitrogen in beef. "Blood Ketone Levels of Young Postpartum Range Cows Increased After Supplementation Ceased," by R. L. Endecott, C. M. Black, K. A. Notah, and M. K. Petersen; "A Comparison of Whole Animal Energy Expenditure by Angus, Holstein, and Wagyu Heifers," by K. A. Ross, C. T. Gaskins, J. J. Michal, D. H. Keisler, and K. A. Johnson; "Effects of Energy Supply on Methionine Utilization by Growing Steers," by G. F. Schroeder, E. C. Titgemeyer, M. S. Awawdeh, and D. P. Gnad; "Evaluation of Soybean Hulls and Protein Sources of Varying Degradability on Steer Performance in Feedlot Receiving Diets," by C. J. Mueller, R. H. Pritchard, and D. L. Boggs.

The objective of this study was to identify small molecule metabolites in a serum sample taken at entry into the feedlot that can predict performance, and animal health. One-hundred and thirty-one Angus x Simmental steers from a single ranch were sampled at a commercial feedlot in Chappell, NE. Blood samples for metabolite analysis, chute score, exit velocity, and blood lactate concentration for temperament classification were collected in addition to feedlot performance data and carcass quality measurements. The GLM and LSM procedures of SAS (SAS 9.4, 2014) were used to evaluate differences between temperament classifications. Steers were divided into three exit velocity classifications one standard deviation from the mean were classified as fast and exit velocities lower than one standard deviation from the mean were slow. Forty metabolites were quantified using 1H NMR Spectroscopy from serum. Metaboloanalyst was used to analyze serum metabolites and phenotypic values using one way-ANOVA, PCA, PLS-DA, and a permutation test to cross validate. Data were normalized and scaled. No metabolites were predictive of any of the animal health metrics collected. Five metabolites were different in exit velocity class at (P < 0.01; Methanol, Isopropanol, Lactate, Isobutyrate, and Pyruvate). Similarly, seven metabolites were different in chute score classes at (P < 0.01) (Methanol, Isobutyrate, Creatinine, Dimethly Sulfone, Hippurate, Isopropanol, and Succinate). Furthermore, several metabolites in serum at entry in the feedlot were related to carcass quality metrics; Back Fat (Urea and 2-Hydroxyisobutyrate at (P < 0.01), a trend for prediction of quality grade at (P = 0.068), carcass value (P = 0.085). The relationship between serum metabolites identified on entry into the feedlot, feedlot performance traits, and eventual carcass quality warrants further research to elucidate the roles these metabolites play during the feedlot period and in predicting carcass merit. [ABSTRACT FROM AUTHOR]

Four ages at harvest (HA: A15, A18, A24 and A30 for 15, 18, 24 and 30 months, respectively) were compared in performance, carcass and meat traits of feedlot finished steers over a 123-day period. Three meat aging periods (postmortem days: 2, 7 and 14) were imposed on a longissimus thoracis muscle (LM) section of each left carcass. Feed efficiency (FE) was greater (P ≤ 0.02) for A15 and A18. Treatment A30 had the lowest FE (P ≤ 0.02). The LM area was largest for A30, but no different (P = 0.15) from A24. Intramuscular fat was lowest (P < 0.01) for A15. No differences were detected (P ≥ 0.11) among the A18, A24 and A30. Treatment A30 had the highest rib fat thickness (P ≤ 0.02) and WBsf values. No differences were detected (P ≥ 0.25) in WBSf between A15, A18 and A24 after any aging period. Results suggested A24 as a threshold for carcass and meat traits. • Feedlot finished 15 and 18-month old steers can have similar feed efficiency. • Up to 24 months of age, feedlot finished steers would not differ in meat tenderness. • Thirty-month old feedlot steers would have tougher meat than 24-month old. • Harvest age of feedlot cattle affects intramuscular and back fat deposition differently. • Aging improves meat tenderness with greater effect on 30-month old feedlot steers. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the impacts of bunk management on animal performance, carcass characteristic, and hydrogen sulfide gas concentrations in beef steers fed modified distillers grains with solubles (MDGS; DM basis). One hundred and thirty-nine steers (initial BW = 240 ± 5.17 kg) were allocated into 16 pens and assigned to one of two treatments: 1) Control-managed bunks: bunks devoid of feed prior to feeding; and 2) Long-managed bunks: bunks with approximately 2.54cm of feed remaining at the time feeding. Treatments were applied during a 28-d adaptation period, during which time, steers were adapted to a common finishing ration containing 25% MDGS (DM basis). Ruminal hydrogen sulfide gas was collected by rumenocentesis from two steers from each of three pens per treatment on d 0, 7, 14, and 28, which correspond to days of diet transition. Animal performance data were collected throughout the study and carcass characteristic data were collected when steers reached market weight. There were no differences (P < 0.13) in BW, ADG, or F:G between treatments during the adaptation period or throughout the entire study. Steers managed with long bunks had greater (P = 0.001) intake during adaptation; however, overall DMI was not different (P = 0.14) between treatments. Hydrogen sulfide gas concentrations were not affected by the day x treatment interaction (P = 0.30) but were affected by day (P = 0.003) with hydrogen sulfide concentrations increasing throughout adaptation. Hydrogen sulfide concentrations tended (P = 0.07) to be greater in steers with long-managed bunks vs. control-managed bunks. There were no differences (P > 0.53) in carcass characteristics. In summary, bunk management had no effect on performance or carcass characteristics and only tended to impact hydrogen sulfide gas concentrations. [ABSTRACT FROM AUTHOR]

Cross-bred steers (n = 397; initial BW = 247 ± 21 kg) from a single ranch were used to determine the effects of supplementing a Bacillus subtilus direct-fed microbial (DFM; CLOSTAT, Kemin Animal Health, Des Moines, IA) at a rate of 13 g ∙ steer−1 ∙ d−1 on feedlot performance, carcass characteristics, and clinical health during receiving and finishing. Steers were randomly assigned to pens by BW and pens were pairwise assigned 1 of 2 experimental treatments, control (CON) or DFM. Steers were housed in 12.2 x 30.5 m soil surfaced pens, and pen served as the experimental unit. There were no differences during the receiving period for overall BW (P = 0.97), ADG (P = 0.91), DMI (P = 0.77), or G: F (P = 0.79). There was a tendency (P = 0.09) for the DFM fed steers to be 14% more efficient from d 0 to 14 of the receiving period. There were also no differences in final BW (P = 0.40) or overall DMI (P = 0.46) during finishing, but there was a difference in ADG (P = 0.03) from d 29 to 56 of the finishing period where steers supplemented with DFM had greater ADG. The DFM supplemented steers also tended to be more efficient overall during finishing and for the entirety of the experiment (P = 0.07 and P = 0.08, respectively). There were no differences in carcass characteristics (P ≥ 0.31) between the experimental treatments. While limited research has been conducted examining the effects of Bacillus subtilis on feedlot performance, carcass characteristics, and the clinical health of growing and finishing steers, the results of this experiment suggest that the supplementation of a strain Bacillus subtilis at a rate of 13 g ∙ steer−1 ∙ d−1 may improve feed efficiency [ABSTRACT FROM AUTHOR]

Simple Summary: A variety of feedstuffs can be used in beef cattle finishing rations. While corn has traditionally been the most popular feed ingredient in the United States, barley, which is better adapted to the growing and climatic conditions of northern latitudes, can also be utilized. This study evaluated the effects of corn and barley finishing rations on cattle performance and behavior in a feedlot system. Corn-fed steers had greater gains and heavier final live weights than barley-fed steers, however, this tended to be accompanied by greater daily intake. No differences in animal behavior were observed between barley or corn-fed steers. Thus, depending on the difference of costs associated with feeding corn or barley in a given year, barley could be a potential high-quality feed source in beef cattle finishing rations. By having a better understanding of feedlot steer performance and behavior of cattle fed either barley or corn-based diets, producers will be more equipped to make informed nutritional management decisions in feedlot production. This study evaluated the effects of barley and corn finishing rations on feedlot performance and behavior of steers. Feedlot rations in this study were comprised of a main concentrate of either corn or barley. Steers were fed in a GrowSafe system to measure individual animal intake and behavior. Weight gain, average daily gain (ADG), and gain:feed were measured for each steer. Feeding behavior including time spent eating (min/day), visits per day, time per visit (min), eating rate (g/min), intake (kg/day), and intake per visit (g) were measured for each individual. Corn-fed steers had greater ADG (p < 0.01) and heavier hot carcass weights (HCW; p < 0.01). In addition, corn fed steers had a higher yield grade than barley fed steers (p < 0.01). No treatment effects (p ≥ 0.11) were observed for time spent eating, visits per day, time per visit, eating rate, intake g/kg body weight, or intake per visit. Although corn-fed steers had a greater ADG and HCW than barley-fed steers, they tended to consume more feed (p = 0.06). Depending on the difference of costs associated with feeding corn or barley, barley could be a potential high-quality feed source in beef cattle finishing rations. [ABSTRACT FROM AUTHOR]

• Winter pen cleaning did not improve steer average daily gain in this study. • More extensive winter pen cleaning improved marbling score. • Increasing extent of pen cleaning improved quality score of carcasses. • More detailed research on impacts of housing on marbling score are warranted. The objective of this study was to evaluate the impacts of winter pen cleaning on livestock performance of beef cattle fed to finish in the northern Great Plains. To accomplish our research objective, 156 mixed-breed beef steers (284 ± 14 kg) were stratified by weight and randomly assigned to one of 12 open-lot feedyard pens for a 195 day feeding study. Treatments were assigned randomly to pen and consisted of: 1) Control - no cleaning, 2) Apron - bunk aprons cleaned twice throughout the study, and 3) Full - entirety of the pen cleaned twice throughout the study. Full pens or bunk aprons were cleaned on d 49 and 133. Pens were stocked at 30.1 m2 of pen space per steer. Steers were adapted to and finished on a common finishing diet. Fresh wheat straw was placed on bedding areas weekly, with an estimated 2.5 kg cereal straw·steer−1· d −1 used as bedding during the study. Pen cleaning did not influence (P ≥ 0.48) animal performance. Hot carcass weight, ribeye area, back fat and yield grade of carcasses were not affected (P ≥ 0.44) by pen cleaning treatment. We observed that increasing extent of pen cleaning increased (P = 0.03) marbling score (444, 463, and 484 ± 11.1 for control, apron, and full, respectively). Increasing extent of pen cleaning resulted in increased (P = 0.03) quality grade of carcasses. Visual assessment of pen condition, apron score, and tag score were impacted by cleaning regimen by period interaction (P ≤ 0.01). Pen cleaning resulted in improved pen conditions or apron scores compared to control pens, and decreased tag scores compared to control steers (P < 0.05). Pen cleaning did not improve animal performance but did improve marbling score of carcasses in this study. [ABSTRACT FROM AUTHOR]

Three hundred and forty crossbred steers were utilized in a two-year study (n = 160, Year 1; n = 180, Year 2) to examine the effectiveness of commercially available genomic testing for predicting carcass characteristics and feedlot performance. Steers in Year 1 were consigned by 8 producers (average entry weight 307 ± 41.4 kg) and in Year 2 by 16 producers (average entry weight 292 ± 38.9 kg) as part of a retained ownership demonstration program. In both years steers were fed in a single pen and fed a common diet with a final energy concentration of 1.36 Mcal NEg/kg. Hair samples for DNA analysis were collected at time of implanting and submitted to be analyzed using two different non-breed specific DNA panels. The PredicGen (PG; Zoetis, Inc., Parsippany-Troy Hills, NJ) test was used in Years 1 and 2 while Igenity Silver (IGS; Neogen, Lansing, MI) was used in Year 1 and Igenity Gold was used in Year 2 (IGG; Neogen, Lansing, MI). Traits evaluated by the PG test were marbling score (PG-Marb), USDA Yield Grade (PG-YG), and Grid Value (PG-GV). Traits evaluated by the IGS test were marbling score (IG-Marb) and ADG (IG-ADG). In addition to IG-Marb and IG-ADG, IGG estimates for fat thickness (IGG-FT) and LM area (IGG-LMA) were added in Year 2. Steers were harvested in three groups at d176, d212, and d240 in Year 1 and d182, d203, and d224 in Year 2 with a target carcass fat thickness of 1.27 cm. Hot carcass weights were recorded on the day of harvest with carcass 12th-rib fat thickness (FT), LM area (LMA), USDA marbling scores and Yield Grades (YG) collected following a 24-h chill. Average daily gain was calculated using initial weights shrunk four percent and HCW divided by 62%. Grid values were derived using the same premiums and discounts across Year 1 and Year 2. Carcass marbling scores were positively correlated with PG-Marb and IG-Marb (0.405, P < 0.001 and 0.493, P < 0.001), respectively. The IGG test was positively correlated with FT and LMA (0.525, P < 0.001 and 0.368, P < 0.001, respectively). The USDA YG was negatively correlated with PG-YG (-0.493, P < 0.001). Average daily gain was correlated with IG-ADG (0.227, P < 0.001) and Grid Value was correlated with PG-GV (0.133, P = 0.016). The PG, IGS, and IGG genomic test results were correlated with actual carcass characteristics of crossbred steers. [ABSTRACT FROM AUTHOR]

Two trials were conducted to evaluate the performance and carcass characteristics of backgrounding and finishing cattle fed canola meal (CM) versus soybean meal (SBM) as a protein supplement with or without wheat dried distillers' grains with solubles (WDDGS). Trial 1 was a 95-d backgrounding program in which 398 steer calves (288 ± 0.27 kg; mean ± SE) were assigned to one of 12 pens and fed one of four barley silage, barley grain-based diets formulated to 13.5% CP and 1.52 and 0.92 Mcal kg-1 NEm and NEg, respectively. The dietary treatments included CM (8.7% DM), SBM (7.0% DM), CM+WDDGS (4.6 & 4.8% DM), and SBM+WDDGS, (4.2 & 4.4% DM). Trial 2 utilized 300 head (306 ± 0.94 kg) assigned to 25 pens for a 61-d backgrounding and 147-d finishing program. Backgrounding diets were identical to Trial 1 with the addition of a fifth treatment (WDDGS, 9.5% DM). The basal finishing diet was barley grain-based and formulated to 13% CP and 1.95 and 1.30 Mcal kg-1 NEm and NEg, respectively. The five dietary treatments included CM (5.7% DM), SBM (4.3% DM), CM+WDDGS (3.0% & 3.1% DM), SBM+WDDGS (2.4% & 2.6% DM), and WDDGS (6.7% DM). Performance results for each trial were analyzed as a completely randomized design using the Mixed model procedure with pen as the experimental unit. Quality and yield grades were analyzed using GLIMMIX with a binomial error structure and logit data transformation. In trial 1, there were no differences between treatments for final BW (420.7 ± 1.8 kg; P = 0.30) or gain-to-feed (G:F) (0.16 ± 0.003; P = 0.60); however, ADG was greatest (P < 0.05) for cattle fed SBM relative to cattle fed SBM+WDDGS (1.45 ± 0.04 kg vs. 1.32 ± 0.03 kg). In trial 2, no treatment differences (P > 0.22) were detected for ADG (1.65 ± 0.01 kg), DMI (9.77 ± 0.07 kg), or G:F (0.17 ± 0.001). Cattle fed SBM+WDDGS had the least subcutaneous fat depth relative to cattle fed CM+WDDGS (1.17 ± 0.06 cm vs. 1.46 ± 0.05 cm; P = 0.02) and the poorest marbling score relative to cattle fed WDDGS (398.75 ± 15.19 vs. 440.10 ± 8.20; P = 0.05). There was a tendency (P = 0.09) for greater proportion of AAA carcasses with the WDDGS treatment (66.1 ± 6.2%) while SBM+WDDGS had the least (41.4 ± 6.5%). These results indicate that CM is equal to SBM as a protein supplement for backgrounding and finishing cattle and that provision of WDDGS as a source of rumen undegradable protein did not benefit performance. The combination of SBM+WDDGS negatively influenced energy partitioning to carcass fat deposition. [ABSTRACT FROM AUTHOR]

Single-source, Angus-cross steers (n = 204; 249 ± 23 kg) were utilized to determine the effect of supplemental vitamin (VE; ROVIMIX E-50 Adsorbate, DSM Nutritional Products) on performance and immunity during feedlot receiving. Seven days post-arrival, steers were blocked by BW and weaning protocol (pre-weaned or not) into pens (n = 5 or 6 steers/pen) and pens randomly assigned to VE treatments: no supplemental VE (CON), VE at 25 IU/kg DM (LOW; average 151 IU·steer-1·d-1), 500 IU·steer-1·d-1 (MED), or 1000 IU·steer-1·d-1 (HIGH). Steers were weighed on d -1, 0, 14, 26 and 27. On d 6, steers were boostered with Bovi-Shield Gold (One Shot, Zoetis). Serum collected from one steer per pen was analyzed for Se and α-tocopherol (d -1 and 26) and Bovine Viral Diarrhea Virus (BVDV) type 1 and 2 antibody titers (d 6, 14, 26). Data were analyzed using Proc Mixed of SAS with pen as the experimental unit (n = 9 pens/treatment), the fixed effects of treatment and block, and the random effect of pen. Linear, quadratic and cubic contrast statements were constructed. Serum Se and α-tocopherol concentrations from d -1 and titers from d 6 (prior to vaccination) served as covariates. From d 14 to 27, ADG and G:F quadratically increased (P ≤ 0.02), with MED being greatest; VE did not affect d 0 to 14 or overall trial performance (P ≥ 0.14). Day 26 BVDV type 1 antibody titers and α-tocopherol concentrations (2.7, 3.4, 4.6, and 5.8 mg/L for CON, LOW, MED, and HIGH, respectively) linearly increased due to VE (P ≤ 0.04). Increasing supplemental VE improved circulating VE concentrations and antibody response to a booster vaccine. Performance benefits were observed when VE was supplemented at 500 IU·steer-1·d-1, the dose recommended by NASEM (2016) for stressed cattle. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to examine the effects of zinc source and concentration on feedlot performance and carcass characteristics of beef steers. In Exp. 1, 179 crossbred steers (325 kg initial BW) were blocked by BW, assigned to four treatments (5 pens/treatment), and fed for 152 d. Steers were fed a 92% concentrate diet based on whole corn and supplemented with 60 mg Zn from ZnSO4/kg DM (CT), 90 mg Zn from ZnSO4/kg DM (30S), CT plus 30 mg Zn from ZINPRO®/kg DM (30M), and CT plus 30 mg Zn from Availa®Zn/kg DM (30A). Steer DMI, carcass-adjusted ADG (1.67, 1.65, 1.66, and 1.72 ± 0.04 kg/d for CT, 30S, 30M, and 30A, respectively), and adjusted ADG:DMI (169, 168, 171, 174 ± 3.7 g/kg) were not altered (P > 0.10) by additional dietary Zn above 60 mg/kg. Carcass characteristics were similar across treatments. In Exp. 2, 262 crossbred steers (281 kg initial BW) were blocked by BW, assigned to three treatments (10 pens/treatment), and fed for 176 d. Steers were fed a 90% concentrate diet based on steam-flaked corn without supplemental Zn (NC), NC plus 90 mg Zn/kg DM from ZnSO4 (S), or NC plus 35 mg Zn/kg DM from Availa®Zn and 55 mg Zn/kg DM from ZnSO4 (AS). Steer DMI (8.59, 8.45, 8.40 ± 0.12 kg/d for NC, S, AS, respectively) and adjusted ADG (1.74, 1.73, and 1.76 ± 0.03 kg/d) were similar. Adjusted ADG:DMI was improved by feeding Zn (P = 0.06); ADG:DMI did not differ between NC and S (P > 0.15; 203 vs 205 ± 2.9 g/kg), but ADG:DMI tended (P = 0.13) to be greater for AS than for S (205 vs 209 ± 2.9 g/kg). Fewer carcasses graded at least low Choice when Zn was fed (P < 0.10), but marbling score was at the juncture between Small and Slight marbling (P < 0.05; 404, 385, and 387 ± 8 for CT, S, and AS, respectively) and net return was not affected. Hot carcass weight, fat thickness, Longissimus muscle area, and yield grade were similar (P > 0.10) among treatments. Gain efflciency by feedlot cattle was improved by providing supplemental Zn, and efflciency tended to favor feeding a blend of Availa®Zn and zinc sulfate. [ABSTRACT FROM AUTHOR]