Increasing corn distillers solubles alters the liquid fraction of the ruminal microbiome.

Five ruminally fistulated steers were used in a 5 × 5 Latin square design to determine the effects of increasing dietary fat and sulfur from condensed distiller's solubles (CDS) on the ruminal microbiome. Treatments included a corn-based control (CON) and 4 levels of CDS (0, 10, 19, and 27%) in a coproduct-based (corn gluten feed and soybean hulls) diet. Fat concentrations were 1.79, 4.43, 6.80, and 8.91% for diets containing 0, 10, 19, and 27% CDS, respectively. Steers were fed for ad libitum intake once daily. After feeding each diet for 18 d, ruminal samples were collected 3 h after feeding on d 19. Samples were separated into solid and liquid fractions. Microbial DNA was extracted for bacterial analysis using paired-end sequencing of the V3 through V4 region of the 16S rRNA gene on the MiSeq Illumina platform and quantitative PCR of selected species. Orthogonal contrasts were used to determine linear and quadratic effects of CDS inclusion. Increasing CDS inclusion decreased (linear, < 0.05) α-diversity and species richness in the liquid fraction. Analysis of Bray-Curtis similarity indicated a treatment effect ( = 0.01) in the liquid fraction. At the phyla level, relative abundance of Bacteroidetes decreased in steers fed increasing dietary inclusion of CDS as Firmicutes increased to 82% of sequences for the 27% CDS treatment. Family Ruminococcaceae increased (linear, < 0.01) 2-fold in the liquid fraction when feeding CDS increased from 0 to 27% CDS, yet genera tended ( = 0.09) to decrease in steers fed greater CDS. The most abundant family of sulfate-reducing bacteria, Desulfovibrionaceae, increased ( < 0.03) in the solid and liquid fraction in steers fed additional dietary CDS and sulfur. Relative abundance of family Veillonellaceae and were increased (linear, ≤ 0.02) in the solid fraction as steers were fed increasing CDS. There were no effects ( > 0.10) of feeding increasing dietary fat from CDS on fibroylytic genus in either fraction. Results demonstrate increasing fat and sulfur from CDS in a coproduct-based diet markedly alters the liquid fraction ruminal microbiome but does not elicit negative effects on relative abundance of identified fiber-fermenting bacteria.

Effects of protein and fat concentration in coproduct-based growing calf diets on adipogenic and lipogenic gene expression, blood metabolites, and carcass composition.

Crossbred calves ( = 30; age = 95 ± 1.7 d; BW = 179 ± 18 kg) were fed 1 of 5 growing diets: 1) corn-based control, 2) low-fat, low-protein coproduct blend, 3) high-fat, low-protein coproduct blend, 4) low-fat, high-protein coproduct blend, and 5) high-fat, high-protein coproduct blend for 112 d (growing phase) followed by a common corn-based finishing diet (additional 112 d; finishing phase). Calves were biopsied at 0, 112, and 224 d for transcriptional analysis via real-time quantitative PCR of 14 genes associated with adipogenesis and lipogenesis within the muscle. Serum was collected at d 0, 112, and 224 and analyzed for leptin, IGF-1, and GH concentration. Treatments were arranged in a 2 × 2 factorial. Data were analyzed using the MIXED procedures of SAS (SAS Inst. Inc., Cary, NC) to ascertain the effects of 2 protein levels, 2 fat levels, time, and any interactions. Increased protein and decreased fat in the growing diet resulted in a carryover effect that increased ( 0.01) gene expression of PPARγ, insulin-induced gene 1, thyroid hormone responsive SPOT14 protein, ATP citrate lyase, adiponectin, diacylglycerol O-acyltransferase homologue 2, fatty acid binding protein 4, fatty acid synthase, phosphoenolpyruvate carboxykinase 1, and stearoyl-CoA desaturase as well as serum leptin concentrations between d 112 and 224. Expression of sterol regulatory element binding transcription factor 1 was increased ( 0.01) at d 112 in steers fed high-protein, high-fat diets compared to those fed high-protein, low-fat diets. A fat × day interaction ( 0.01) occurred for the expression of adiponectin receptor 2 and CCAAT/enhancer binding protein alpha, resulting in a carryover effect wherein low-fat diets fed during the growing phase increased expression of both genes at the end of the finishing phase (d 224). After slaughter, cattle fed the control during the growing phase tended ( 0.09) to have greater marbling scores, whereas other carcass parameters were not different ( ≥ 0.13). These data indicate that feeding differing levels of dietary fat and protein during the growing phase does affect i.m. adipogenesis at the transcriptional level, but differences in gene expression were not sufficient to affect carcass quality among cattle fed coproducts.

Effect of an injectable trace mineral at the initiation of a 14 day CIDR protocol on heifer performance and reproduction.

Three experiments were conducted at separate locations to determine the effects of a trace mineral injection (TMI), Multimin 90, on heifer performance and reproduction. In Exp. 1, [spring-born, Angus, n = 93, body weight (BW) = 428 ± 45.2 kg], Exp. 2 (spring-born, Angus × Simmental, n = 120, BW = 426 ± 54.0 kg), and Exp. 3 (fall-born, commercial Angus, n = 199, BW = 345 ± 39.7 kg) heifers were stratified by BW within experiment and assigned to 1 of 2 treatments: a control, saline injection, or TMI at a dose of 1 mL/68 kg BW. Free choice mineral, containing Cu, Mn, Se, and Zn formulated to meet or exceed NRC recommendations, was supplemented to heifers. Injections were given 33 d prior to breeding at the initiation of a 14-d controlled internal drug release (CIDR)-prostaglandin protocol. There was no difference (P ≥ 0.37) in BW during Exp. 1. Additionally, there was no difference (P ≥ 0.52) in body condition score (BCS) at initiation or at artificial insemination (AI) and final pregnancy confirmation in Exp. 1; however, a greater (P = 0.03) BCS was noted for control heifers at breeding. Pregnancy rates to timed AI and overall pregnancy rates were also similar (P ≥ 0.74) regardless of treatment. During Exp. 2, BCS and BW did not differ (P ≥ 0.44) across treatments. There was a tendency (P = 0.07) for TMI heifers to have an increased AI pregnancy rate (62 vs. 45%) compared with control heifers despite no difference (P = 0.51) in overall pregnancy rate. In Exp. 3, BW was not different (P ≥ 0.39) across all time points. Also, BCS did not differ (P ≥ 0.45) at initiation, AI, or final pregnancy conformation. Interestingly, there was a tendency (P = 0.10) for TMI heifers to have an increased BCS at the time of breeding compared with control heifers. However, there were no differences (P ≥ 0.50) in AI and overall pregnancy rates. In 1 of 3 experiments, an injectable trace mineral administered 33 d prior to the breeding season in conjunction with a 14-d CIDR protocol, tended to increased AI conception rates of heifers even when adequate trace mineral supplement was provided. The variable response observed across experiments may be caused by differences in breed, calving season, mineral sources, and management strategies.

Effects of supplementing methionine hydroxy analog on beef cow performance, milk production, reproduction, and preweaning calf performance.

Mature Simmental × Angus cows (214 cows; 635 ± 7 kg) were utilized to determine the effects of late gestation and early postpartum supplementation of methionine hydroxy analog (MHA) on cow BW, BCS, milk production, milk composition, reproduction, and calf performance until weaning in a fall-calving, cool-season grazing system. Cows were stratified by BW, age, AI sire, and assigned to 1 of 12 pastures (17 or 18 cows·pasture). Pastures were randomly allotted to 1 of 2 treatments: control (0.45 kg·cow·d of wheat midd-based pellets, = 6) or supplement including MHA (0.45 kg·cow·d of wheat midd-based pellets including 10 g MHA supplied as MFP (Novus International, Inc., St. Charles, MO; = 6). Treatments were fed 23 ± 7 d prepartum through 73 ± 7 d postpartum. Cow BW was collected at postcalving (27 ± 7 d postpartum), end of supplementation (73 ± 7 d postpartum), AI, pregnancy check, and end of trial (192 and 193 ± 7 d postpartum). At 73 ± 7 d postpartum, a subset of cow-calf pairs was used in a weigh-suckle-weigh procedure to determine milk production, and milk samples were taken to determine milk composition ( = 45·treatment). Serum from blood was collected at 73 ± 7 and 83 ± 7 d postpartum to determine cow cyclicity and concentrations of 2-hydroxy4-(methylthio) butanoic acid (HMTBa) and L-Methionine. After supplementation, all cow-calf pairs were managed as a common group until weaning (193 ± 7 d of age). Cows were bred via AI at 97 ± 7 d postpartum and clean-up bulls were turned out 11 d post-AI for a 55-d breeding season. Cows fed MHA had greater ( < 0.01) serum concentrations of HMTBa. Cow BW and BCS were not different ( ≥ 0.10) at any time points between treatments. There was no treatment effect ( ≥ 0.17) on calf birth BW, calf weaning BW (193 ± 7 d of age), or calf ADG. Calculated 24-h milk production, milk composition and component production did not differ ( ≥ 0.21). There were no differences ( ≥ 0.50) in percentage of cows cycling, AI conception rate, and overall pregnancy rate between treatments. Post-trial nutritional modeling suggests cows experienced several nutritional deficiencies beyond methionine (Met) that limited the response to Met supplementation. Although supplementation of MHA during late gestation through estimated peak lactation increased serum HMTBa concentrations, it did not affect cow performance, cow milk production, or calf performance when fall-calving cows grazed cool-season forages.

Effects of timing and duration of test period and diet type on intake and feed efficiency of Charolais-sired cattle.

Objectives of this experiment were to: 1) determine appropriate test length, timing, and repeatability of DMI, ADG, and efficiency over different biological time points; 2) determine the efficacy of using decoupled performance and intake data to generate accurate feed efficiency measures; and 3) determine the relationship between forage-and grain-feed efficiency measures. Over 2 yr, Charolais crossbred heifers ( = 308) and steers ( = 320) were fed for two 70 d periods and DMI, ADG, and 12th rib fat thickness were recorded. Steers were fed grain-based diets during the growing and finishing periods to determine the effects of test period and timing on DMI and feed efficiency. Heifers were fed forage during the growing period and grain during the finishing period to test the effect of diet type on measures of DMI and feed efficiency. For each 70 d test period, individual DMI was recorded using the GrowSafe (Airdrie, AB) system. Residual feed intake (RFI) was calculated for each test period. Total feeding period ADG (FP_ADG) was calculated for steers by regressing all weights taken from feedlot arrival to final BW, which was calculated by dividing HCW by a standard dressing percentage (63%). Dry matter intake and RFI were correlated (r 0.56; < 0.01, and 0.63; < 0.01, respectively) for the growing and finishing periods of grain-fed steers. Average daily gain was not repeatable ( = 0.11; 0.06) across both test periods for steers. However, growing and finishing ADG were correlated ( = 0.58; < 0.01, and = 0.69; < 0.01, respectively) to FP_ADG. To assess the potential of shortening the intake test, DMI was analyzed in 7 d increments for grain-fed steers during the growing and finishing periods. Regardless of test length, from 7 to 70 d, DMI was strongly correlated ( ≥ 0.87; < 0.01) to total DMI during the growing period. Heifer forage DMI was correlated ( = 0.58; < 0.01) to grain DMI; subsequently, forage and grain RFI were moderately correlated ( = 0.40; < 0.01). This study suggests that DMI is repeatable across varying stages of maturity in cattle, and accurate feed efficiency measures can be obtained in either the growing or finishing period. The relationship of forage and grain DMI and efficiency in heifers suggests that measures of DMI and feed efficiency in heifers are relevant, regardless of diet fed. Intake evaluation periods can be shortened with minimal effects on the accuracy of predicting individual animal DMI.

Long-term Effects of Pyrethrin and Cyfluthrin, a Type II Synthetic Pyrethroid, Insecticide Applications on Bull Reproductive Parameters.

The objectives of this study were to determine effects of cyfluthrin and pyrethrin spray products, used in combination with cyfluthrin topical and ear tag applications, on bull reproductive parameters over 18 weeks. Angus or Angus x Simmental bulls were randomly assigned to one of three treatment groups: (i) no exposure to pyrethrins/cyfluthrin (CONT; n = 10), (ii) cyfluthrin ear tag and topical applications (ET; n = 10), or (iii) cyfluthrin ear tag, topical, premise spray and pyrethrin fog spray applications (ET+S; n = 8). Bull body weight was measured every 3 week, and body condition score and scrotal circumference were recorded on weeks 0, 9 and 18. Semen and serum were collected every 3 weeks for sperm evaluation and testosterone measurement, respectively. There was a treatment × week interaction (p < 0.01) for sperm with primary defects; bulls in CONT group had a greater (p = 0.01) percentage of sperm with primary defects than bulls treated with insecticides at week 18. Overall and progressive sperm motility, normal sperm morphology, secondary sperm defects and serum testosterone concentrations changed (p < 0.01) over time in all bulls; however, treatment did not affect (p ≥ 0.13) any of these parameters. There were also no treatment effects (p ≥ 0.08) on bull body weight, body condition score or scrotal circumference. The use of pyrethrin- and cyfluthrin-based insecticides, regardless of application, did not negatively affect reproductive parameters in beef bulls when administered over 18 weeks.

Influence of excessive dietary protein intake during late gestation on drylot beef cow performance and progeny growth, carcass characteristics, and plasma glucose and insulin concentrations.

Spring-calving cows ( = 49) were used to investigate the effects of excessive prepartum dietary protein intake on late gestation cow performance as well as subsequent progeny growth, carcass characteristics, and plasma glucose and insulin concentrations. Treatments were formulated to be isocaloric and provide 100% (REQ) or 129% (HP) of CP requirement. Treatments were limit-fed 78 ± 12 d prepartum to calving. All cows were fed a common diet postpartum. Cow BW and BCS were recorded at initiation of treatments and within 48 h post-calving. Milk production was estimated via the weigh-suckle-weigh technique 69 ± 11 d postpartum. Calf BW was measured at birth and at weaning (121 ± 11 d of age). Progeny ( = 42) were weaned as a group and placed into a feedlot and fed a common finishing diet. Glucose and insulin concentrations were analyzed on a subset of progeny (12 per treatment) 90, 120, 150, 180, 210, and 240 min post-feeding, 2 d before slaughter (342 ± 11 d of age). Treatment had no effect ( ≥ 0.22) on cow BW, BCS, milk production, and subsequent reproduction or progeny preweaning growth. Progeny finishing growth and marbling scores were not affected ( ≥ 0.24) by treatment, yet 12th rib fat thickness ( < 0.01), KPH ( = 0.04), and YG ( = 0.01) were greater for progeny born to HP dams. Progeny born to HP dams had decreased ( ≤ 0.01) glucose and insulin concentrations, and insulin to glucose ratios, indicating greater insulin sensitivity. Although feeding cows 129% of CP requirement during late gestation did not affect cow performance or progeny preweaning or finishing period growth; carcass adiposity was increased by maternal treatment.

Effects of chromium supplementation to feedlot steers on growth performance, insulin sensitivity, and carcass characteristics.

Objectives were to determine the effects of chromium propionate supplementation on growth performance, insulin and glucose metabolism, and carcass characteristics of beef cattle. Steers ( = 34) were stratified by BW and assigned to 1 of 2 treatments: 1) no supplemental Cr (Cont) or 2) 3 mg supplemental Cr·steer·d (CrP). Both supplements, Cont and CrP, were delivered via 0.454 kg ground corn top-dressed on the basal diet. There was no effect ( ≥ 0.45) of CrP on ADG, DMI, G:F, or final BW. However, steers fed CrP needed more ( = 0.10) days on feed (DOF) to achieve the same carcass back fat (BF) as steers fed Cont. There were no effects ( ≥ 0.41) of CrP on HCW, BF, or KPH. Steers fed CrP had increased ( = 0.01) dressing percentage (DP) and tended to have a 4.21 cm greater LM area ( = 0.15), decreased marbling scores ( = 0.11), and decreased intramuscular fat ( = 0.11) compared to steers fed Cont. There were no differences ( ≥ 0.25) in quality or yield grade distributions. A glucose tolerance test was conducted early (21 DOF) and late (98 DOF) in the finishing phase. There was a feedlot treatment (FT) × time × DOF interaction ( = 0.08) for glucose concentrations, but no other interactions ( ≥ 0.21) for glucose or insulin concentrations. There were no FT × DOF interactions ( ≥ 0.21) for insulin area under the curve (iAUC), insulin:glucose ratio, insulin or glucose baseline, or peak insulin or glucose concentrations. At 21 DOF, steers fed CrP had decreased glucose area under the curve (gAUC; = 0.01), decreased glucose clearance rate (; = 0.02), and increased glucose half-life (T; = 0.07) compared to steers fed Cont; however, by 98 DOF, no differences were observed between treatments. At 98 DOF, all steers, regardless of treatment, had increased ( < 0.01) peak glucose and insulin, , iAUC, insulin:glucose ratio, and baseline insulin when compared to values at 21 DOF, but gAUC and T decreased ( < 0.01). Although steers fed CrP tended ( = 0.11) to have increased baseline glucose concentrations compared to steers fed Cont, CrP supplementation did not affect ( ≥ 0.17) other measures of glucose or insulin. Results of this study indicate that CrP increased DP and tended to increase LM area but tended to decrease intramuscular fat, with no effect on growth performance. With increased DOF, all steers became more insulin resistant, using more insulin to clear less glucose, and these effects were not mitigated by CrP supplementation.

Effects of cows grazing toxic endophyte-infected tall fescue or novel endophyte-infected tall fescue in late gestation on cow performance, reproduction, and progeny growth performance and carcass characteristics.

Very little is known regarding the effects of cow exposure to toxic ergot alkaloids in late gestation and the subsequent, long-term effects on progeny. Therefore, the objectives were to determine the effects of grazing toxic endophyte-infected tall fescue () or novel endophyte-infected tall fescue during late gestation on cow BW, BCS, hair coat score (HCS), respiration rates, milk production, and reproduction and on growth performance and carcass characteristics of progeny. Eighty gestating, Angus × Simmental cows (age = 6.68 ± 0.32 yr; 588 ± 16 kg initial BW; initial BCS = 5.66 ± 0.28) were stratified by initial BW and allocated into 8 pasture groups (10 cows/group) with 4 groups per treatment. Each group was allotted to 1 of 2 grazing treatments: toxic endophyte-infected tall fescue ('Kentucky-31'; E+) or novel endophyte-infected tall fescue ('Jesup MaxQ'; NOV). Cows were placed on grazing treatments at 110 ± 6 d prepartum (May 28, 2014) and remained on treatment until the end of the calving period (October 8, 2014; 23 ± 6 d postpartum). Cow BW and BCS did not diverge ( ≥ 0.15) at any time point among grazing treatments. However, cows grazing E+ had increased ( < 0.05) respiration rates and HCS and reduced ( < 0.05) prolactin concentration compared with cows grazing NOV. Calf birth BW, Julian calving date, milk production, AI conception rate, and overall pregnancy rate did not differ ( ≥ 0.23) by grazing treatment. In a subsequent grazing period of the progeny, dam grazing treatment did not affect ( ≥ 0.14) respiration rates, HCS, or prolactin concentration of the progeny when all progeny grazed E+ pastures. However, progeny born to dams grazing NOV tended ( > 0.06 to ≤0.10) to have increased BW at 70 ± 6 d of age, 205 d (adjusted weaning BW), and throughout the postweaning calf grazing period. Despite a tendency for BW to differ throughout the postweaning calf grazing period, finishing phase performance and carcass characteristics of progeny did not differ ( ≥ 0.20) between dam grazing treatment. In conclusion, results indicate that by the time progeny enter the feedlot and are finished on a high-grain diet, any fetal programming effects are minimal.

Influence of late gestation drylot rations differing in protein degradability and fat content on beef cow and subsequent calf performance.

Spring-calving, mature cows ( = 191 total) and their progeny were used to evaluate the effects of late gestation drylot rations differing in RUP and fat content on cow performance as well as performance and carcass characteristics of subsequent progeny. Cows were blocked by BW and anticipated calving date and assigned to 16 pens. Pens were randomly allotted to 1 of 2 treatments: limit-fed corn coproducts and ground cornstalks (COP; TDN = 64.4%, CP = 11.1%, RDP = 60.2% of CP, and fat = 5.1%) or limit-fed ground mixed, cool-season grass hay (HY; TDN = 55.7%, CP = 9.5%, RDP = 86.0% of CP, and fat = 2.3%). Treatments were limit fed as isocaloric, isonitrogenous rations from 88 ± 11 d prepartum to calving. All cows were fed a common diet postpartum. Cow BW and BCS were collected at the beginning of the feeding period, within 48 h after calving, and at breeding. Calf BW was collected at birth and at 64 ± 11 and 124 ± 11 d of age. Milk production was determined using the weigh-suckle-weigh technique at 64 ± 11 and 124 ± 11 d postpartum. At 124 ± 11 d of age, steers ( = 68) and nonreplacement heifer calves ( = 25) were weaned and placed on a common feedlot diet with individual feed intake monitored using GrowSafe. Feedlot calves were slaughtered at a commercial facility 35 ± 10 d after a minimum ultrasound 12-rib fat thickness estimation of 0.9 cm. After calving, cow BW was greater ( < 0.01) and BCS was greater ( < 0.01) for cows fed COP than for cows fed HY. Calf birth BW was greater ( = 0.04) for those born to cows fed COP with no difference ( = 0.43) in percentage of unassisted births across treatment. Cows fed HY were lighter ( < 0.01) at breeding with lower BCS ( = 0.03); nevertheless, overall pregnancy rate was not different ( = 0.80). No differences ( ≥ 0.22) in milk production were detected. For feedlot progeny, initial feedlot BW, final BW, and days on feed were not different ( ≥ 0.23), and as a result, no difference ( = 0.21) in feedlot ADG was detected. Feedlot DMI and G:F were not different ( ≥ 0.19) across treatments. Feedlot calf health was monitored with no differences ( ≥ 0.68) in morbidity and mortality observed. No differences ( ≥ 0.27) were detected for HCW, LM area, backfat, marbling score, yield grade, or KPH. Increased dietary RUP and fat content during late gestation increased cow BW and BCS but did not alter milk production, subsequent reproduction, or subsequent calf performance or carcass characteristics.

Effects of late gestation distillers grains supplementation on fall-calving beef cow performance and steer calf growth and carcass characteristics.

Fall-calving, mature Angus and Simmental × Angus cows ( = 251 total) and their progeny were used to evaluate the effects of late gestation dried distillers grains plus solubles (DDGS) supplementation on cow performance and progeny growth and carcass characteristics. Cows were blocked by breed and allotted to 12 tall fescue pastures (6.8 ha average). Pastures were randomly assigned to 1 of 2 treatments: cows were offered 2.1 kg DM DDGS·cow·d (SUP; CP = 23%, fat = 7%; = 6 pastures) or were not offered a supplement (CON; = 6 pastures) 69 ± 9 d before expected calving date. Cows remained on treatments until calving. Once weekly, cows that had calved were removed from treatment pastures and were moved to new tall fescue pastures (21.6 ha average) where cows from both treatments were comingled without further supplementation. Cows ( = 74) were removed from study for calving more than 30 d after expected calving date, calf loss and injury, or euthanasia. Cow BW and BCS were recorded at the beginning of the supplementation period, after calving, and at breeding. Calf BW was taken at birth and early weaning (82 ± 14 d of age). After weaning, 71 steer progeny (representative of dam breed and treatment pastures) were transitioned to a common feedlot diet with individual feed intake monitored using the GrowSafe feeding system. Steers were slaughtered at 47 ± 4 d after a minimum 12th rib fat thickness (back fat) estimation of 0.6 cm, with cattle being shipped in 3 groups. Forage availability was not different between treatments ( = 0.69). Cows offered SUP gained more BW and BCS ( ≤ 0.02) during the supplementation period. There were no differences ( ≥ 0.12) in calving date, calf birth or weaning BW, or preweaning ADG. Cow BW at breeding was not different ( = 0.19); however, BCS at breeding was greater ( < 0.01) for cows offered supplement. No differences ( ≥ 0.11) in milk production, AI conception, or overall pregnancy rate were detected. For steer progeny, initial feedlot BW, final BW, and days on feed were not different ( ≥ 0.35); no difference ( = 0.77) in feedlot ADG was detected. Feedlot DMI and G:F were not different ( ≥ 0.52) across treatments. No differences ( = 0.62) in morbidity were observed in the feedlot. No differences ( ≥ 0.19) were detected for HCW, LM area, marbling score, or yield grade. Prepartum DDGS supplementation improved cow BW and BCS but did not alter milk production, subsequent reproduction, or subsequent calf performance or carcass characteristics.

Prepartum supplement level and age at weaning: I. Effects on pre- and postpartum beef cow performance and calf performance through weaning.

Objectives were to determine the interaction of prepartum supplement level and age at weaning on cow BW, BCS, milk production, reproduction, and calf performance up to weaning in a fall-calving system over 2 yr. Mature, multiparous, Angus × Simmental cows (yr 1: 326 cows, 9 pastures, BW = 632 ± 67 kg, and BCS = 5.7 ± 0.58; yr 2: 383 cows, 9 pastures, BW = 606 ± 70 kg, and BCS = 5.8 ± 0.74) were used in a split-plot design that included 3 supplement levels-no supplement (NS), low supplement (LS; 2.16 kg∙cow∙d), or high supplement (HS; 8.61 kg∙cow∙d)-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 distillers' grains with solubles and 30% soybean hulls) 103 ± 11 d prepartum to 2 ± 11 d postpartum. Cow BW was greater ( < 0.01) for cows fed HS at precalving (49 ± 11 d prepartum), postcalving (26 ± 11 d postpartum), and postbreeding (81 d after AI) compared with cows fed NS and LS. Prepartum supplementation did not affect ( ≥ 0.62) calf birth BW, percent of calves dead at birth, or percent of cows calving unassisted. Prepartum supplementation tended ( = 0.10) to improve AI conception. Early weaning increased ( ≤ 0.05) AI conception and postbreeding cow BW and BCS compared with cows with NW calves. Neither prepartum supplementation nor age at weaning affected ( ≥ 0.28) overall pregnancy rate. At time of early weaning, BW was increased ( = 0.05) for steers from cows fed LS compared with steers from cows fed NS. Steer BW at time of normal weaning and ADG between early and normal weaning was greater ( < 0.01) for EW steers compared with NW steers. A year × age at weaning interaction occurred ( < 0.01) for ultrasound marbling score at time of normal weaning. In yr 1, marbling was decreased ( = 0.04) for EW steers compared with NW steers; however, in yr 2, marbling was increased ( < 0.01) for EW steers compared with NW steers. In conclusion, there was no interaction between level of supplement during late gestation and age at weaning on cow BW, BCS, milk production, AI conception, and overall pregnancy rate in mature beef cows nor in their steer progeny's BW or ultrasound marbling. Both prepartum supplementation and early weaning improved cow BW, BCS, and reproduction. Minimal effects of dam prepartum supplement level on calf performance up to weaning were observed. Early weaning improved calf growth but had inconsistent effects on ultrasound marbling across years.

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.

Effect of dietary fat concentration from condensed corn distillers' solubles, during the growing phase, on beef cattle performance, carcass traits, digestibility, and ruminal metabolism.

The objectives of this study were to determine the effect of fat concentration from corn distillers' solubles (CDS), fed during the growing phase, on DMI, gain, carcass traits, digestibility, ruminal metabolism, and methane emissions of steers. In Exp. 1, 40 steers (age = 136 ± 20 d; BW = 185 ± 11 kg) were randomly allotted to 1 of 5 dietary treatments: 1) a cosrn-based gro\wing diet (CNT), 2) 0% CDS, 3) 10% CDS, 4) 19% CDS, or 5) 27% CDS. Diets 2 through 5 included coproducts (corn gluten feed and soybean hulls) and were formulated to achieve fat concentrations of 3, 5, 7, and 9%, respectively. Diets were fed once daily for 106 d (growing phase). All steers were fed a corn-based diet from d 107 to 196. Contrasts were used to examine 1) the difference between CNT and 10% CDS and 2) linear and quadratic effects of CDS inclusion. During the growing phase, steers fed CNT had increased ( < 0.01) ADG and G:F compared with steers fed 10% CDS. Increasing CDS inclusion increased (linear, ≤ 0.02) ADG and G:F. Overall, steers fed CNT had increased ( < 0.01) ADG compared with steers fed 10% CDS, but increasing CDS inclusion had no effect ( = 0.19) on overall ADG. Overall DMI and G:F were not different ( ≥ 0.16) in any contrast. There was a trend (Linear; = 0.08) for ultrasound marbling at d 196 to increase as CDS inclusion increased; however, there were no effects ( ≥ 0.20) of treatment on carcass marbling or quality grade. In Exp. 2, 5 steers (BW = 335 ± 56 kg) were fed Exp. 1 diets for ad libitum intakes in a 5 × 5 Latin square design. Apparent DM digestibility increased (linear, = 0.02) with increasing dietary CDS inclusion. Steers fed CNT had greater ( = 0.01) DM digestibility than those fed 10% CDS. Fat digestibility increased (linear, < 0.01) in steers with increasing CDS, but NDF and ADF digestibility were not affected ( ≥ 0.17) by treatment. Similarly, ruminal pH and VFA concentrations were not affected ( ≥ 0.13). Also, there was no difference ( ≥ 0.37) in ruminal methane emissions (g/h). In conclusion, feeding corn during the growing phase increased overall ADG compared with 10% CDS coproduct-based diet but did not affect carcass traits or methane production. Increasing dietary fat inclusion from CDS in coproduct-based diets linearly increased DM and fat digestibility and predicted marbling scores via ultrasound but did not affect marbling at slaughter, NDF digestibility, propionate, or methane production.

Effects of protein and fat concentration in coproduct-based growing calf diets on performance and carcass composition.

Angus×Simmental crossbred heifers (n=150) and steers (n=100) were used to evaluate 1 of 5 growing diets: 1) a corn-based growing diet (CRN); 2) a high-fat, high-protein coproduct blend; 3) a high-fat, low-protein coproduct blend; 4) a low-fat, high-protein coproduct blend; and 5) a low-fat, low-protein coproduct blend in a 2×2+1 factorial arrangement. Low-protein and low-fat diets were formulated to be isonitrogenous and isofat to CRN (16.0% CP and 3.0% fat), and high-protein and high-fat diets were formulated to have 20.0% CP and 5.0% fat, respectively. Calves were weaned at 85±1.2 d, blocked by weight, and allotted to pens (10 calves/pen) within sex (10 pens of steers and 15 pens of heifers). The objective of this experiment was to determine if the concentration of protein or fat or their interaction in coproducts used in growing diets fed to early-weaned calves affects feedlot performance or carcass composition. Starting on d 0, calves (141±1.2 d of age) were fed experimental diets for 112 d and then fed a common feedlot diet for an additional 112 d. Body weight, hip height, and ultrasound data were collected at the end of each 112-d feeding phase. Carcass data included HCW, LM area (LMA), 12th-rib back fat (BF), marbling score (MS), KPH, and USDA quality grade. There was no fat×protein interaction (P≥0.27); therefore, only main effects are discussed. No effects (P≥0.47) of CRN, protein, or fat were detected for BW at d 112 or 224. Increased dietary protein resulted in greater (P=0.04) ADG at d 112 compared to calves fed low protein. Feeding cattle CRN decreased (P=0.04) DMI and increased (P<0.01) G:F during the growing phase compared to coproducts. High-fat diets increased (P=0.05) BF in calves at d 112 compared to low-fat diets. High-protein diets decreased (P=0.02) ultrasound MS at d 112 compared to low-protein diets. Carcasses from cattle fed high-fat diets had greater (P=0.03) MS compared to those from cattle fed low-fat diets. No differences (P≥0.14) were observed for HCW, LMA, BF, KPH, or yield grade. These data indicate that final BW was unaffected by protein and fat content of growing calf diets but that increased dietary fat and low dietary protein increased MS.

Effects of calcium oxide treatment of dry and modified wet corn distillers grains plus solubles on growth performance, carcass characteristics, and apparent digestibility of feedlot steers.

The objectives of this study were to determine the effects of feeding dried corn distillers grains (DDGS) or modified wet corn distillers grains (MDGS) with or without CaO treatment to feedlot steers on 1) growth performance and carcass characteristics and 2) diet digestibility, pattern of intake, and meal distribution. In Exp. 1, steers (n = 139; average initial BW = 336 ± 75 kg) were used in a randomized complete block design. Treatments were arranged in a 2 × 2 factorial design, and pens were randomly allotted to 1 of the 4 dietary treatments (DM basis): 1) 50% DDGS untreated, 2) 48.8% DDGS treated with 1.2% CaO, 3) 50% MDGS untreated, or 4) 48.8% MDGS treated with 1.2% CaO. The remainder of the diet was corn husklage, dry rolled corn, and vitamin and mineral supplement. In Exp. 2, fistulated steers (n = 8; average initial BW = 540 ± 250 kg) were used in a replicated 4 × 4 Latin square design with the same dietary treatments as in Exp. 1. There was no interaction (P ≥ 0.14) between distillers grains plus solubles (DGS) and CaO inclusion for DMI, ADG, final BW, or USDA yield and quality grades. However, steers fed CaO-treated DGS had decreased (P < 0.01) DMI, regardless of DGS type. Because CaO treatment decreased DMI without affecting (P = 0.66) ADG, steers fed CaO-treated DGS had increased (P < 0.01) G:F compared to steers not fed CaO. The variation in DMI found in this experiment could be explained by differences in meal size and distribution. Steers fed CaO-treated DGS ate a similar (P = 0.36) number of meals but ate smaller (P < 0.01) meals. No effects (P ≥ 0.55) of CaO treatment or its interaction with DGS type were found for apparent total tract DM or NDF digestibility. However, steers fed MDGS had increased (P < 0.01) NDF digestibility compared to steers fed DDGS. In conclusion, CaO treatment of DGS improved feed efficiency when DGS-based diets were fed but did not improve digestibility.

Relationship among performance, carcass, and feed efficiency characteristics, and their ability to predict economic value in the feedlot.

A 4-yr study was conducted using 736 steers of known Angus, Simmental, or Simmental × Angus genetics to determine performance, carcass, and feed efficiency factors that explained variation in economic performance. Steers were pen fed and individual DMI was recorded using a GrowSafe automated feeding system (GrowSafe Systems Ltd., Airdrie, Alberta, Canada). Steers consumed a similar diet and received similar management each year. The objectives of this study were to: 1) determine current economic value of feed efficiency and 2) identify performance, carcass, and feed efficiency characteristics that predict: carcass value, profit, cost of gain, and feed costs. Economic data used were from 2011 values. Feed efficiency values investigated were: feed conversion ratio (FCR; feed to gain), residual feed intake (RFI), residual BW gain (RG), and residual intake and BW gain (RIG). Dependent variables were carcass value ($/steer), profit ($/steer), feed costs ($/steer • d(-1)), and cost of gain ($/kg). Independent variables were year, DMI, ADG, HCW, LM area, marbling, yield grade, dam breed, and sire breed. A 10% improvement in RG (P < 0.05) yielded the lowest cost of gain at $0.09/kg and highest carcass value at $17.92/steer. Carcass value increased (P < 0.05) as feed efficiency improved for FCR, RG, and RIG. Profit increased with a 10% improvement in feed efficiency (P < 0.05) with FCR at $34.65/steer, RG at $31.21/steer, RIG at $21.66/steer, and RFI at $11.47/steer. The carcass value prediction model explained 96% of the variation among carcasses and included HCW, marbling score, and yield grade. Average daily gain, marbling score, yield grade, DMI, HCW, and year born constituted 81% of the variation for prediction of profit. Eighty-five percent of the variation in cost of gain was explained by ADG, DMI, HCW, and year. Prediction equations were developed that excluded ADG and DMI, and included feed efficiency values. Using these equations, cost of gain was explained primarily by FCR (R(2) = 0.71). Seventy-three percent of profitability was explained, with 55% being accounted for by RG and marbling. These prediction equations represent the relative importance of factors contributing to economic success in feedlot cattle based on current prices.

The effect of breed and individual heterosis on the feed efficiency, performance, and carcass characteristics of feedlot steers.

This study was conducted to evaluate maternal breed effects, direct breed effects, and individual heterosis on subsequent steer performance, carcass, and feed efficiency traits. This was a consecutive 2-yr trial using 158 steers. The same dam breeds, Angus (AN) and purebred Simmental (SM), were used both years. Also, the same AN and SM sires (n=11) were used both years. Steers were AN, SM, or AN×SM breed composition. Steers were managed similarly before weaning and early weaned at 56±9 d of age. Steers were then randomly allotted to pens and fed a common finishing ration. Contrasts were written to evaluate direct and maternal breed effects and individual heterosis in the PROC MIXED procedure of SAS (SAS Inst. Inc., Cary, NC) using dam breed, sire breed, and year as fixed effects. Simmental direct breed effect resulted in a 26 kg heavier initial BW (P<0.05) and a 46 kg heavier final BW (P<0.05). Simmental maternal breed effect increased initial BW by 43.5 kg (P<0.05). Dry matter intake was not impacted by direct breed effects, maternal breed effects, or individual heterosis. Individual heterosis did improve G:F 3.4% (P<0.05) and residual BW gain 0.048 kg/d (P<0.05). Residual intake and BW gain tended (P=0.07) to improve as a result of individual heterosis. Residual feed intake (RFI) was impacted by direct breed effect with SM cattle having a more desirable RFI (P=0.05). Angus direct breed effect increased backfat (P<0.05) and improved marbling score by 126 units (P<0.05). Simmental direct breed effect increased LM area (P<0.05), had the highest HCW at 410 kg (P<0.05), and had the most desirable yield grade at 2.74 (P<0.05). Individual heterosis improved marbling score (P=0.05). Maternal breed effect increased HCW (P<0.05) as a result of the SM dam. Direct breed effects were present for performance, feed efficiency measures, and carcass traits. Overall, heterosis impacted feedlot performance, carcass characteristics, and feed efficiency, which impacts beef production.