Steer Carcass Characteristics Research Articles

Effect of Allicin and Illite Supplementation on the Methane Production and Growth Performance of the Beef Cattle

Background: Methane reduction technology has not yet been put into practical use because of problems such as reduced digestibility, increased costs, additives remaining and microbial adaptations. The objectives of this study were to evaluate the effects of allicin and illite supplementation on ruminal methane production, growth performance and carcass characteristics of the Hanwoo steers. Methods: For the in vitro experiment, 3 Hanwoo cows equipped with rumen fistula were used. The 28 Hanwoo steers were randomly assigned to one of the four dietary groups: control (CON), T1 (1.0% illite), T2 (0.1% allicin), or T3 (1.0% illite and 0.1% allicin). All data were analyzed using the generalized linear model procedure. Result: The methane production was rapidly increased for all the treatments after 8 h, but decreased compared to the control after 24 h (P less than 0.05) of incubation. There was no difference in the growth performance and carcass characteristics of steers among the treatments. Thus, allicin 0.1% and/or illite 1.0% have the potential to be used as natural feed additives to reduce methane production.

Feeding microalgae (Schizochytrium limacinum) to beef steers increases meat omega-3 content

New alternatives to increase the content of polyunsaturated beef fat are necessary. Feed supplements like microalgae are a strategy to enrich meat with omega 3. The aim of the study was to evaluate growth performance, fatty acid profile of meat and carcass characteristics of steers fed with microalgae in the diet. Sixteen steers (mean weight 299.6 ± 7.4 kg, seven months) were randomly assigned to two groups: the control group (CTL) and the microalgae group (ALG; daily feeding of 1.7% of dry matter as microalgae). The diet (40% corn silage and 60% concentrate) was offered twice daily for 84 days. Microalgae supplementation was associated with a 4.44-fold increase in total omega-3 fatty acids in the longissimus thoracis and lumbar muscle, reflecting a 3.6-fold reduction in the omega-6: omega-3 ratio. The concentration of 20: 5n3 and 22: 6n3 increased by 7 and 20.5 times, respectively, with the addition of microalgae. However, microalgae decreased the consumption of dry matter (P <0.0001) by 16.5%, the average daily gain (P = 0.035) by 19.1% and the muscle water-holding capacity (P = 0.02) by 5.5% compared to control. The use of microalgae reduces growth performance, but does not alter the characteristics of the carcass and has the potential to improve the FA profile of the omega 3 series. Consumers may be attracted to increase their intake of polyunsaturated omega 3 fat from beef. These results can support the decision of nutritionists and farmers to use microalgae in beef cattle, as it becomes economically viable.

428 The Effect of Protein Concentrations in Finishing Diets on Growth Performance and Carcass Characteristics of Steers.

428 The Effect of Protein Concentrations in Finishing Diets on Growth Performance and Carcass Characteristics of Steers.

639 Effect of trace mineral supplementation with or without hormone implants on growth and carcass characteristics of steers

To determine the effects of trace mineral (TM) supplementation and hormone implant strategy on growth and carcass characteristics of cattle, 72 Angus-cross steers (388 ± 17 kg) were blocked by BW (6 steers per pen) to a 2 × 3 factorial. Steers were either implanted (d 0 with Component TE-IS, reimplanted d 56 with Component TE-200; IMP) or not (NoIMP). Within implant treatments cattle received no supplemental TM (CON), TM supplemented at 2016 NRC recommendations of 10 Cu, 30 Zn, 20 Mn, 0.10 Se, 0.15 Co, and 0.50 I (mg/kg; NRC), or TM supplemented at feedlot consultant recommendations of 20 Cu, 100 Zn, 50 Mn, 0.30 Se, 0.20 Co, and 0.50 I (mg/kg; IND). Blood samples were collected on d -7, 70 and 124. Steers received a finishing diet for 124 d in GrowSafe bunks and were harvested on d 125. Data were analyzed in SAS as a 2 × 3 factorial with the fixed effect of block, and steer as experimental unit (n = 12 per combination). Day -7 glucose concentrations were used as a covariate in analysis. There was a tendency (P = 0.06) for an IMP × TM for d 124 plasma glucose with NoIMP/NRC being greater than NoIMP/IND and all other treatments intermediate. There were no IMP × TM for final BW, overall ADG, DMI, G:F, dressing percent, backfat, marbling score, or KPH (P ≥ 0.17). Overall ADG tended (P = 0.07) to be and HCW was (P = 0.03) affected by TM, where IND was greater than CON (HCW: 373, 378, and 388 kg for CON, NRC, and IND, respectively). Overall DMI was increased by TM (P < 0.0001) with NRC and IND being greater than CON. Steers receiving implants had greater (P < 0.0001) final BW (559 and 617 kg for NoIMP and IMP, respectively), overall ADG (1.35 and 1.83 kg for NoIMP and IMP, respectively), DMI, G:F, and HCW (359 and 400 kg for NoIMP and IMP, respectively) than NoIMP. There was an IMP × TM (P = 0.02) for ribeye area (REA) with IMP/CON having greater REA than IMP/IND, with IMP/NRC being intermediate; NoIMP had smaller REA, regardless of TM supplementation. There was an IMP × TM (P = 0.02) for YG where NoIMP/IND was greater than IMP/CON with all other treatments intermediate. These data indicate NRC TM recommendations might not be adequate for finishing beef steers, irrespective of hormone implant administration.

336 Evaluation of zero or three hundred milligrams of Optaflexx on growth performance and carcass characteristics of steers fed to different degrees of finish

336 Evaluation of zero or three hundred milligrams of Optaflexx on growth performance and carcass characteristics of steers fed to different degrees of finish

Beef cow prepartum supplement level and age at weaning: II. Effects of developmental programming on performance and carcass composition of steer progeny.

Objectives were to determine the interaction of prepartum dam supplement level and age at weaning on growth performance, glucose and insulin concentrations, and carcass characteristics of steers (134 steers in yr 1; 147 steers in yr 2). Mature, multiparous Angus × Simmental cows were used in a split-plot design that included 3 supplement levels (no supplement [NS], 2.16 kg·cow·d [LS], and 8.61 kg·cow·d [HS]) and 2 ages at weaning (78 ± 11 d of age [early weaned; EW] or 186 ± 11 d of age [normal weaned; NW]). Cows grazed endophyte-infected tall fescue/red clover pastures and were bunk fed supplement (70% dried distiller's grains plus solubles and 30% soybean hulls) 103 ± 11 d prepartum to 2 ± 11 d postpartum. Dam prepartum supplement level did not affect ( ≥ 0.29) finishing phase growth performance or morbidity. The percentage of steers grading Average Choice or greater was increased ( = 0.04) for steers from cows fed HS compared to the percentage of steers from cows fed NS. Early weaning increased ( < 0.01) finishing phase initial BW and final BW and reduced ( < 0.01) G:F compared to normal weaning. A year × wean interaction ( = 0.04) occurred for ADG; EW resulted in reduced ( < 0.01) ADG compared to NW in yr 2. At slaughter, EW steers had greater ( < 0.01) HCW, yield grade, and back fat than NW steers. A year × wean interaction ( ≤ 0.05) occurred for quality grade distribution; in yr 2, EW steers had a greater ( < 0.01) proportion of carcasses that graded Low Choice or greater and Average Choice or greater than carcasses from NW steers. The EW steers had greater ( ≤ 0.05) occurrence of single antibiotic treatments in yr 2 and mortality due to respiratory disease than NW steers. A trend for a year × wean interaction ( ≤ 0.07) occurred for plasma insulin concentration and insulin:glucose; EW steers had numerically greater plasma insulin concentrations and insulin:glucose than NW steers in yr 1. In conclusion, these data suggest that there is no interaction between maternal level of supplement during late gestation and age at weaning on steer finishing phase performance, glucose and insulin concentrations, and carcass yield and quality characteristics. Overfeeding supplement to the dam did not affect finishing phase growth performance but did improve quality grades of steers. Early weaning increased HCW and improved carcass quality. Both dam supplement level and age at weaning are effective strategies in increasing beef quality and are independent of each other.

Intake, performance and estimated methane production of Nellore steers fed soybean grain

The objective of this study was to evaluate nutrient intake, performance, estimated methane production and carcass characteristics of steers fed diets containing three different levels of soybean grain: 0, 120 and 230 g/kg on the dry matter (DM). The study was conducted on eighteen castrated Nellore males with an average initial body weight (BW) of 370±12 kg in a completely randomized design, with three treatments and six repetitions. Intake of dry matter (DMI, kg/day) and crude protein tended to decrease linearly, and the intake of ether extract increased linearly in response to the soybean grain levels in the diet. Levels of soybean grain in the diet did not affect DMI (g/kg of BW), final average weight, average daily weight gain, feed efficiency and estimated methane production. Animals fed diets with different levels of soybean grain were not different with respect to carcass yield, loin eye area, subcutaneous fat thickness, or bone, muscle and fat ratios. Carcass characteristics and meat quality were also not significantly different. Replacement of soybean meal by soybean grain in the diet alters the intake of crude protein and ether extract but does not affect performance, estimates of methane production, or carcass characteristics of feedlot Nellore.

Effects of a combining feed grade urea and a slow-release product on performance, dietary energetics and carcass characteristics of steers fed finishing diets

Recent findings have shown that microbial nitrogen flow and digestible energy of diet are increased when urea (U) is combined with a slow-release urea product (SRU) in diets with a starch:acid detergent fibre (S:ADF) ratio of 4.5, while feed grade U has shown greater effects on growth performance or dietary energy utilization when the diet contains a S:ADF ratio of greater than 5.0. These results can be partially explained by the better synchronization of ruminal degradation rates between those U sources with the carbohydrates of the diets. Therefore, 60 crossbreed steers (372.4 ± 15 kg) were used to evaluate the effects of combining U and SRU in a diet with a S:ADF ratio of 4.5 vs. U that was supplemented in diets with different S:ADF ratios (3.5, 4.5 and 5.5) on growth performance, dietary energetics and carcass characteristics. U combination did not affect average daily gain (ADG), but reduced dry matter intake [DMI, as % of body weight (BW)] enough to increase feed efficiency (G:F) and dietary net energy (NE). As the S:ADF ratio increased, the DMI, ADG, G:F and NE of diet increased linearly. Irrespective of the S:ADF ratio, U diets did not modify neither the observed-to-expected NE ratio nor the apparent retention per unit DMI, while U combination increased by 7.2% and 8.4%, respectively, the observed-to-expected dietary ratio and the apparent retention per unit DMI. U combination had no effect on carcass characteristics. As the S:ADF ratio increased, carcass weight and LM area were increased linearly. Combining feed grade U and SRU in diets with a 4.5 starch:fibre ratio resulted in positive effects on the efficiency of utilization of dietary energetics.

Encapsulation of flaxseed in a dolomitic lime matrix: effects on feedlot performance and carcass characteristics of steers vs. heifers (2014)

Introduction Polyunsaturated fatty acids, when fed to cattle, are subject to extensive alteration by ruminal microbes, effectively converting the polyunsaturated fats into saturated fats. The oil of flaxseed is rich in alpha linolenic acid (~55% of the oil), which is an essential polyunsaturated, omega-3 fatty acid. Enrichment of feedlot cattle diets with flaxseed has been used effectively as a means of increasing the proportions of omega-3 fatty acids incorporated into beef, but efficiency of transfer from the animal’s diet to beef is relatively low. Encapsulating the flaxseed or flaxseed oil in a matrix that is resistant to the actions of ruminal microbes could provide a mechanism for increasing the efficiency with which polyunsaturated fats are absorbed and deposited into tissues.

Effect of frame score on performance and carcass characteristics of steers finished in the feedlot or backgrounded for various time on pasture and finished in the feedlot

Abstract. A two-year data of three-year study integrating pasture and drylot feeding systems was used to examine effect of frame score on performance and carcass characteristics of steers. Each year, 84 fall-born and 28 spring-born calves of similar genotypes were used. Fall-born and spring-born calves were started on test in May and October, respectively. Treatments were: 1) fall-born calves directly into feedlot; 2 and 3) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of July; 4 and 5) fall-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October; 6 and 7) spring-born calves put on pasture with or without an ionophore and moved to the feedlot at the end of October. Frame scores were determined by taking steers’ age and live weight into consideration. Cattle that grazed the same duration on pasture were regarded as the same treatment regardless of whether they received an ionophore or not. In the feedlot, steers were provided an 82 % concentrate diet containing whole-shelled corn, ground alfalfa hay, and a protein, vitamin and mineral supplement containing ionophore and molasses. Pens of cattle were harvested at approximately 522 kg. Cattle having a higher frame score at the entry to pasture and grazed until July and October tended to have higher and lower daily gain on pasture than those having lower frame score, respectively (P&gt;0.05). Fall-born and spring-born cattle grazed until October, which had higher frame scores at the entry to pasture tended to have higher daily gain in the feedlot showing a compensatory growth. In the feedlot, within each treatment cattle having higher frame score tended to have higher daily gain (P&gt;0.05) and had higher dry matter intake (P&lt;0.05). Cattle spending longer time in the feedlot have better carcass quality and higher yield grades. Results showed that cattle with higher frame scores had higher growth potentials in the feedlot and if the grazing season is extended then daily gain of cattle having higher frame score decreases.

Effects of Distillers Dried Grains with Solubles as a Protein Source in Creep Feed. 2. Subsequent Feedlot Performance, Carcass Measurements, and Plasma Parameters

<h2>ABSTRACT</h2> A 2-yr study was conducted to evaluate the effects of protein source in a creep ration as well as creep vs. no creep treatments on subsequent feedlot performance and carcass characteristics of steers. During each year, 36 steer calves were assigned to treatments: corn distillers dried grains with solubles (DDGS) or soybeanmeal (SBM) as the protein sources compared with a noncreep dietary treatment. After the creep feeding phase, they were placed in the feedlot. During the receiving period in both years, creep-fed steers tended to have greater DMI (P < 0.10) than noncreep-fed steers, resulting in different (P < 0.01) ADG between creep-fed and noncreep-fed steers in yr 1, but not yr 2. During both years, cost of gain tended to be lower (P ≤ 0.11) for creep vs. noncreep-fed steers. During the grow-ing period in yr 1, noncreep-fed steers were more efficient (P < 0.01) than creep-fed steers, and SBM steers tended to be more efficient (P < 0.10) than DDGS steers. During the growing period in both years, noncreep-fed steers tended to have greater (P < 0.10) ADG than creep-fed steers. In yr 1, creep-fed steers had greater (P < 0.05) final live weights and hot carcass weights, and tended to have greater (P ≤ 0.10) dressing percent, fat thickness, yield grade, and carcass value as compared with noncreep-fed steers. In yr 2, there were no differences in subsequent feedlot performance and carcass characteristics attributed to previous creep feeding treatment. In yr 2, DDGS had lower (P < 0.05) longissimus muscle area than SBM steers. In conclusion, protein source had no effect on ADG or final weight; however, DDGS tended to reduce the cost of gain.

Efficacy of mid-summer doramectin pour-on application for parasite control in spring calving cow-calf herds in the Northern Great Plains

One-hundred-twenty cow-calf pairs grazing native pasture in southcentral North Dakota were used in a prospective study to evaluate efficacy of mid-summer topical doramectin application for control of lice compared to non-treated controls. Pairs were allocated to one of two treatment groups and placed on eight separate pastures. On day -40, cows were weighed and body condition score (BCS) evaluated. On day 0 (day of treatment) pairs allotted to the treatment group were treated topically with 227 mcg/lb of doramectin in mid-July. Cows were examined for lice monthly from day 134 through day 238. Fecal samples collected from cows and calves were examined for parasite eggs, and horn fly counts were taken on selected cows in each replicate. Weights and BCS (cows only) were taken for cows and calves. Steer calves were committed to a finishing program to evaluate effect of doramectin on feedlot performance and carcass characteristics. Percentage of cows positive for lice in the doramectin-treated group was lower on days 161-162, 184-185, 210-211 and 238-239 than non-treated cows. Doramectin-treated cows and calves had lower fecal egg counts on days 21 and 42 than non-treated controls. Mid-summer application had no effect on cow BCS, cow body weight, calf average daily gain or steer carcass characteristics. Mid-summer application of doramectin was effective for control of lice through the winter. Internal parasite load in this study may not have been high enough to detect a difference in performance in spring calving cow-calf pairs.

Características da carcaça de bovinos de quatro grupos genéticos submetidos a dietas com ou sem adição de gordura protegida

Com o objetivo de avaliar o rendimento e as características de carcaça de quatro grupos genéticos de bovinos, foram abatidos 32 animais machos inteiros, dos grupos Nelore (N), F1 Canchim x Nelore (CN), F1 Limousin x Nelore (LN) e F1 Aberdeen Angus x Nelore (AN), com idade aproximada de 19 meses e peso vivo médio de 558 kg, terminados em regime de confinamento, recebendo dietas com ou sem adição de gordura protegida, durante 166 dias. O delineamento experimental utilizado foi inteiramente casualizado, com quatro repetições, seguindo esquema fatorial 2 x 4 (dieta, grupo genético). Observou-se efeito do grupo genético sobre o rendimento de cortes primários, tendo o grupo AN apresentado as maiores médias de dianteiro (41,65%) e ponta de agulha (13.90%) e o grupo LN, o maior rendimento de traseiro (47,40%). A área de olho de lombo (AOL) sofreu efeito da dieta, apresentando médias de 81,31 cm² vs. 88,50cm², para as dietas sem e com gordura protegida, respectivamente. A composição física da carcaça foi influenciada pelo grupo genético, tendo o grupo LN apresentado a maior porcentagem de músculo (63,62%) e a menor porcentagem de tecido adiposo (21,65%), enquanto o grupo Nelore apresentou a maior porcentagem de tecido adiposo (28,28%) e menor porcentagem de músculo (56,76%). A composição química da seção HH sofreu efeito do grupo genético, tendo sido observados os maiores teores de proteína bruta nos grupos LN (27,24%) e CN (26,10%) e de extrato etéreo no grupo Nelore (68,35%), que não diferiu do grupo AN (68,02%). Os menores teores de Ca, P e Mg (2,62; 1,32; e 0,081%) foram observados no grupo Nelore.

22PRODUCTION OF A CLONED CALF USING KIDNEY CELLS OBTAINED FROM A 48-HOUR COOLED CARCASS

The ability to produce cloned livestock using postmortem tissue could incorporate an additional application into the field of nuclear transfer. This study examined the feasibility of producing cloned cattle using a primary cell line established from a postmortem beef carcass. A market beef heifer processed at a USDA-certified slaughterhouse was used to develop a primary somatic cell line. Tissue samples were taken from the kidney and forelimb regions either 1) immediately following slaughter (fresh) or 2) 48h postslaughter (cooled) where the carcass was housed at 2 to 4°C. Tissue was removed and placed on ice in PBS+5.0% (v:v) penicillin/streptomycin. A primary culture was established using standard techniques and cultured in supplemented DMEM F-12 medium. Once established, cells were trypsinized and either frozen or continually passaged. Cells used for nuclear transfer (NT) were passaged (48h before use) and cultured with 15μM roscovitine roughly 24h prior to nuclear transfer. Cells were approximately 80% confluent and between passage numbers 1 and 11 at the time of NT. Selected slaughterhouse-derived oocytes were matured in supplemented TCM 199 medium for 18–20h at 39°C in 5.0% CO2 and air. Mature Metaphase II oocytes were vortexed and stained with Hoechst 33342 to help with chromatin removal. Following enucleation, roscovitine-treated carcass cells were placed in the perivitelline space of the oocyte. Reconstructed NT embryos were fused in Zimmermann’s medium and pulsed using needle-like electrodes. This was followed by activation using a combination of calcium ionophore (5μM), cytochalasin D (5μgmL−1), and cycloheximide (10μgmL−1) in TCM+10% FBS. Fused NT embryos were cultured in 50-μL drops of BARC medium (USDA, Beltsville, MD) for 7 days at 39°C in a 5% CO2, 5% O2 and 90% N2 environment. Embryo development for all four groups (Table 1) was assessed with blastocysts (grade 1 or 2) being transferred into recipient cows 7 days post-estrus. Cleavage rates were not significantly different between groups, and the use of either fresh or cooled cells did not impact blastocyst formation. However, there was a significant difference (P=0.05) in % blastocyst based on the source of the donor cell. Overall, one live calf resulted from 34 transferred NTs produced using kidney cells taken from a 48h cooled carcass. These results display the feasibility of producing cloned calves from cells collected post mortem, which ultimately could be used as a tool to select breeding bulls based on their own steer carcass characteristics. Table 1 Embryo development and pregnancy data for the production of beef carcass clones

Idade de desmame e suplementação no desenvolvimento e em características de carcaças de novilhos de corte

O experimento foi conduzido na Estação Experimental da Universidade Federal do Rio Grande do Sul, município de Eldorado do Sul, Brasil, a fim de avaliar o desempenho de 40 bezerros filhos de vacas cruzas Bos indicus x Bos taurus até os dois anos de idade, desmamados precocemente (DP), com média de idade de 91 dias e mínimo de 70 kg de peso vivo, ou desmamados à idade convencional (DC), média de 170 dias de idade e peso médio de 131,2 kg, suplementados (Su) ou não (NSu) com ração energético-protéica com 14% de proteína bruta e 75% de nutrientes digestíveis totais, durante 91 dias no primeiro inverno. O delineamento experimental utilizado foi o delineamento completamente casualizado. Os novilhos do DP foram mais leves até um ano de idade (DP=208,7 kg x DC=233,5 kg). Aos 18-20 meses de idade, os novilhos não eram mais estatisticamente diferentes em seus pesos vivos (DP=279,9 kg x DC=292,5 kg). Ao abate, os pesos vivos médios foram de 432,3 kg (DC) e 414,0 kg (DP), não diferindo também no rendimento, acabamento, conformação e classificação das carcaças. O desmame precoce não impediu o desenvolvimento e o abate dos novilhos aos dois anos de idade. A suplementação no primeiro inverno não alterou o desempenho dos novilhos ao abate.

Interrelationships among carcass characteristics of feedlot steers and heifers selected for competition (2001)

We evaluated the interrelationships among carcass characteristics of steers and heifers selected from commercial feedlots for competition in the Beef Empire Days live and carcass contests. Because judging criteria are weighted heavily on cutability, the majority of cattle entered were trim and muscular. Within this highly selected group, heifer carcasses had larger ribeye areas, lower hot carcass weights, more ribeye area/100 lbs. of hot carcass weight, and a higher percentage of kidney-pelvic-heart fat than steers. However, steers graded USDA Choice or better 4% more often than heifers. Ribeye area, ribeye area/100 lbs. of hot carcass weight, and percentage of kidneypelvic- heart fat increased as dressing percentage increased; however, 12th rib fat thickness had no effect on dressing percentage. Percentage of carcasses grading USDA Choice or better tended to decrease with improved dressing percentage. As 12th rib fat thickness increased, ribeye area and ribeye area/100 lbs. of hot carcass weight decreased whereas percentage of kidneypelvic- heart fat and hot carcass weight of steers increased. As 12th rib fat thickness increased up to 0.50-0.59 inches, the percentage of cattle that graded low Choice or higher increased, but more finish did not result in further increase in percentage of low Choice or better. This study indicates that ribeye area is more closely related to economically important carcass characteristics in trim, muscular cattle than previously identified.

Preweaning growth traits for Senepol, Hereford, and reciprocal crossbred calves and feedlot performance and carcass characteristics of steers.

We conducted a multiyear study in two phases to determine preweaning performance traits of Senepol (S x S), Hereford (H x H), and reciprocal (S x H and H x S) F1 crossbred calves and feedlot performance and carcass characteristics of steers. In Phase I, from 1985 to 1989, data from S x S (n = 194), H x H (n = 383), and S x H (n = 120) calves were used. Numbers of S x S cows were increased during Phase I so that data from H x S (n = 74) calves could be included in Phase II (1990 to 1992) in addition to S x S (n = 118), H x H (n = 130), and S x H (n = 56) calves. Also during Phase II, feedlot performance and carcass characteristics were determined for S x S (n = 30), H x H (n = 26), H x S (n = 36), and S x H (n = 26) steers. In Phase I, S x S calves had heavier (P < .01) birth weights and heavier (P < .01) 205-d adjusted weaning weights than H x H calves. Birth weights of S x H calves were heavier (P < .01) than the mean of the purebred calves, but 205-d adjusted weaning weights did not differ (P > .10). In phase II, direct heterosis was 3.5% for birth weight (P < .05) and 5.1% for 205-d adjusted weaning weight (P < .01). Senepol maternal breed effects were 1.9 kg for birth weight (P < .10) and 37.9 kg for 205-d adjusted weaning weight (P < .01). Levels of direct heterosis, Senepol maternal breed effects, and Hereford direct breed effects were significant for most feedlot performance traits of steer calves that were fed to a common end point. Breeds did not differ (P > .10) for USDA yield and quality grades, and direct heterosis was not significant for Warner-Bratzler shear force. These results demonstrate significant levels of heterosis in preweaning performance between S x S and H x H calves and in feedlot performance of steers. Levels of heterosis were smaller and nonsignificant for most carcass traits including meat tenderness, which did not differ between S x S and H x H steers in this study.

Nutrient utilization by sheep and performance and carcass characteristics of steers fed crab waste-straw silage.

Crab waste preserved with .2% NaOCl was mixed with wheat straw, liquid molasses, and water (32:32:16:20, wet basis) and ensiled for a minimum of 8 wk with microbial inoculant. A reduction in pH and water-soluble carbohydrates (WSC) and a higher concentration of lactic acid (4.9%, DM basis) were achieved. The trimethylamine (TMA) concentration in the silage was 11.2 mg N/100 g. In a digestion trial, 18 crossbred wethers (43 kg) were fed three diets: 1) basal, 2) a 50:50 mixture, DM basis, of basal and crab waste-straw silage, and 3) 100% crab waste-straw silage. Apparent digestibility of DM, OM, CP, energy, NDF, ADF, cellulose, and hemicellulose decreased linearly (P < .01) with increased levels of crab waste-straw silage. Nitrogen retention increased linearly (P < .05) with level of crab waste-straw silage. Apparent absorption was higher (P < .01) and retention was positive (P < .05) for Ca, Mg, Na, K, Cu, and Fe for sheep fed the highest level of crab waste-straw silage. In a 108-d trial, 30 yearling steers were fed diets in which crab waste-straw silage was included in the diet at 0, 15, and 26%, DM basis. Average daily gain tended to be highest (linear effect, P < .15) and carcass weights were highest (linear effect, P < .05) for steers fed 26% crab waste-straw silage. Average carcass quality grade was low Choice, and yield grade averaged 2.3, with no significant differences among treatments. Consumption of crab waste-straw silage did not adversely affect the taste of the meat. Results indicate that feeding crab waste-straw silage did not adversely affect nutrient utilization or performance of ruminants.

Carcass Characteristics of Steers from Two Genetic Types of Angus Cattle Developed on Either Forage or Feedlot Regimens

The objective of this study was to compare carcass characteristics of a sample of small, early-maturing Angus steers (Angus-I) to those of a sample of modern Angus steers (Angus-II). Steers were developed as contemporaries on either pasture (n = 68) or grain diet (n = 66) regimens over 8yr (1987 to 1994). Within each regimen, carcass data were analyzed using a model that included terms for year, genetic type, year × genetic type interaction, and age of steer as a covariate. The Angus-II steers had heavier (P<0.05) live weight, hot carcass weight, and chilled carcass weight than Angus-I steers (for pasture: 374 ± 5 vs 338 ± 6, 217 ± 3 vs 195 ± 4, and 210 ± 3 vs 191 ± 4 kg, respectively; and for feedlot: 428 ± 6 vs 365 ± 10, 261 ± 4 vs 222 ± 6, and 255 ± 4 vs 218 ± 6 kg, respectively). Longissimus muscle area, fat thickness, marbling, and yield grade were higher (P<0.05) for Angus-II than for Angus-I feedlot-developed steers but did not differ for pasture-developed steers. Angus-II steers had more total retail cuts on a weight basis than Angus-I steers for both regimens, whereas total retail cuts as a percentage of chilled carcass weight differed for pasture-developed steers (73 vs 71%; P<0.05) but not for feedlot-developed steers. Total lean product and bone in the right side of the carcass was higher (P<0.05) for Angus-II than for Angus-I for both regimens. Total fat (kilograms) was higher (P<0.05) for Angus-II than for Angus-I feedlot-developed steers but did not differ for the pasture-developed steers. When expressed as a percentage of the chilled right side, total fat was lower and total bone was higher for Angus-II (P<0.05) pasture-developed steers, whereas no differences were seen in percentage total lean or fat for feedlot-developed steers. Pasture-developed Angus-II steers had a higher (P<0.05) percentage of foreshank, chuck, round, and sirloin, and a lower percentage of plate, when expressed as a percentage of chilled carcass weight than pasture-developed Angus-I steers. For both feedlot- and pasture-developed steers, some differences in carcass characteristics and composition existed between the two types of Angus cattle. Beef with acceptable quality and palatability traits can be produced with an all-forage diet.

Effects of programmed gain strategies on performance and carcass characteristics of steers.

In Trial 1, 161 Angus x Simmental crossbred steers (initial BW 305 +/- 1.0 kg) were used in a completely randomized design experiment to determine the effects of intake restriction and programmed gain on cattle performance and carcass composition and characteristics. Five feeding systems were tested using step-wise increases in programmed intake level. Initially steers were fed to gain 1.13 kg/d. Intake was then increased to achieve a gain of 1.36 kg/d. At the end of the feeding period, steers had ad libitum access to feed. Duration of intake restriction and the period of unrestricted intake was varied. Feeding steers at restricted intakes and then increasing daily gain by increasing feed intake using four different schedules all reduced (P < .05) daily feed intake and total feed intake compared with providing ad libitum access to feed throughout the trial. Furthermore, daily feed efficiency was increased (P < .05) by two of the feeding systems compared with offering ad libitum access to feed throughout the trial. The feeding system used did not affect (P > .10) quality grade of the carcasses. In Trial 2, 77 individually penned Angus x Simmental crossbred steers (initial BW 273 +/- 1.2 kg) were used to determine the effects of various feed intake restriction systems. For systems 1 through 4, multiple periods of restriction and realimentation were investigated; the duration and magnitude of restriction were varied. Feed intake was not restricted for steers in system 5. The feed restriction systems used in this experiment did not result in decreased total feed intake or changes in carcass composition as compared with offering ad libitum access to feed. Reducing total energy intake seems to be a prerequisite to altering feed efficiency of steers in limit-feeding systems.