12th Rib Fat Thickness Research Articles

PSII-A-8 Examining the Effects of Providing Injectable Mineral, Oral Mineral or Both to High-Risk Calves Relative to Weight Gain, Ribeye Area and Backfat Thickness

Abstract In some regions of the US, cattle range large areas that do not provide adequate mineral levels and due to the area, mineral supplementation is not possible. Weaned calves from this production system exhibit decreased production performance due to their deficient mineral status. However, there is currently no best practices to supplement these calves with mineral when they are received into a confined feeding setting. As such, this research examined the effects of different mineral supplementation strategies on weight gain, 12th rib fat thickness (REFT) and ribeye area (REA) of sixty feedlot steers obtained from a sale barn in an area known to be mineral deficient. Initially animals were stratified by weight into four different treatment groups (n=15): control (CON), dietary mineral (DM), multimin+dietary mineral (MM+DM), or Multimin (MM) and fed in pens equipped with GrowSafe bunks. Steers received their treatment for the first 40 d of the trial; after this time all steers received the DM treatment. Days 0, 5, 11, 40, 59, 95, 120 and 148 weights were recorded and d 4, 56, and 148 REA and REFT were measured via ultrasound. All data were analyzed using the PROC MIXED procedure of SAS with day as a repeated measure to determine the main effect of treatment. Weight, REA and REFT each increased (P< 0.05) over time. Treatment impacted (P=0.02) weight such that steers receiving the DM treatment gained more (P< 0.05) than those receiving MM+DM and MM, but were no different (P=0.25) than CON steers. Additionally, treatment impacted (P=0.05) REFT such that CON steers had increased (P=0.02) REFT than MM steers, but no other treatment groups were different (P >0.10) from one another. This study suggests that mineral supplementation strategy during the first 40 d of confined feeding may impact production parameters of mineral deficient steers.

Effect of a Bacillus probiotic strain on Nellore cattle finished on pasture during the dry season

The objective of this study was to evaluate the productive performance of Nellore bulls raised under grazing conditions during the dry season and fed a diet supplemented with a Bacillus probiotic strain, and its influence on ruminal and intestinal mucosa development. In addition, the probiotic effects on digestibility and ruminal fermentation were determined. The experiment was conducted between July and November 2017, corresponding to the dry period in the state of Goias, Brazil. Eighty-four animals (approximately 24 months old) were included in the study. Four animals were randomly slaughtered at the beginning of the experiment to assess carcass yield. The remaining animals (80 Nellore bulls, initial body weight (BW) of 354 ± 3.4 kg) were blocked based on their initial BW and assigned to one of two treatments: concentrate with probiotics and concentrate without probiotics (control). Bulls were divided into 16 paddocks of palisade grass (Urochloa brizantha spp.) pasture, supplemented with concentrate at 2% BW. After 133 days, the animals were slaughtered, and carcass traits were measured. Tissues from the ruminal ventral sac and jejunum were collected to evaluate the morphology of the rumen papillae and intestinal villi. No differences were detected in performance data; a tendency was found in improving the dressing percentage, carcass average daily gain (ADG), and gain to feed ratio based on carcass ADG. The 12th rib fat thickness was significantly lower in animals fed probiotic than in control group (4.06 vs. 2.97 mm, p < 0.05). No significant effect on the development of the ruminal and intestinal epithelia was observed with the use of probiotics. Later, an in vivo digestibility trial was carried out to investigate the influence of the Bacillus probiotic strain on rumen fermentation, with the same treatments, using eight rumen-cannulated steers in a cross-over design. Fecal output and forage intake were estimated using titanium dioxide and indigestible neutral detergent fiber (iNDF), respectively. Administration of the probiotics did not improve dry matter (DM) intake or nutrient digestibility. Isovalerate levels were higher in animals fed probiotics (2.01 vs. 1.55, p < 0.05), and no other differences were observed in the rumen fermentation parameters. The tested Bacillus probiotic strain significantly reduced carcass fat deposition in Nellore bulls finished in tropical grass pastures supplemented with a high-concentrate diet during the dry season.

Effects of Mineral Methionine Hydroxy Analog Chelate in Diets on Meat Quality, Muscular Amino Acids and Fatty Acids in Pigs

Background: Organic trace minerals can improve the improve the bioavailability and reduce the environmental pollution, but the effect of organic trace minerals on meat quality of pigs are still unclear. Methods: Adult healthy 33.68 kg pigs (n = 253) were randomly allotted to six dietary treatments, with 6 pens per treatment and 7-8 pigs per pen in a completely randomized design: 1) ITM: inorganic trace minerals with 20, 100, 40 and 60 mg/kg of Cu, Fe, Mn and Zn in sulfate form; 2) T1: ITM was replaced with 20% mineral methionine hydroxy analog chelate (MMHAC); 3) T2: ITM was replaced with 40% MMHAC; 4) T3: ITM was replaced with 60% MMHAC; 5) T4: ITM was replaced with 80% MMHAC; 6) T5: ITM was replaced with 100% MMHAC. Result: In the present study, shoulder fat thickness, the 6th to 7th rib fat thickness (P less than 0.05), the 10th rib fat thickness, the last rib fat thickness and lumbosacral fat thickness tended to decrease with the increase of the MMHAC. In addition, MMHAC increased pH by 1.05~3.68% and reduced drip loss by 5.08~19.77% and cooking loss by 2.67~7.67% compared with the ITM group. Furthermore, MMHAC reduced methionine by 3.51~7.02%, phenylalanine by 1.14~3.41%, arginine by 1.52~3.79% compared with ITM group. Our results showed that MMHAC improved carcass traits, meat quality and meat flavor partly compared with the ITM group.

Feeding a high-energy finishing diet upon arrival to high-risk feedlot calves: effects on health, performance, ruminal pH, rumination, serum metabolites, and carcass traits.

This study evaluated the impacts of feeding a high-energy finishing diet during both the receiving and finishing period compared with a lower-energy receiving diet with adaptation to the finishing diet on health, performance, serum chemistry, ruminal pH, rumination, and carcass characteristics of high-risk feedlot cattle. Five truck-load blocks of steers (n = 101) and bulls (n = 299) were used in a generalized complete block design and randomly assigned to receive: 1) finishing diet for the entire feeding period (FIN) or 2) receiving diet for the first 56 d, followed by a transition to the finishing diet (REC). All cattle were fed ad libitum and consumed the same diet by day 74. A subset of cattle (n = 48) was randomly selected to quantify ruminal pH, temperature, and rumination time. Ultrasound images were collected on days 0, 74, and 146 to determine fat thickness over the 12th rib and rump, and carcass characteristics were determined after slaughter. Cattle fed FIN had less (P < 0.01) dry matter intake (DMI) from days 0 to 74, but DMI did not differ (P = 0.80) after day 74. From days 0 to final, DMI was 0.26 kg less for FIN compared with REC (P = 0.01). However, calculated metabolizable energy intake was not different from days 0 to 74 (P = 0.19), days 74 to final (P = 0.80), or overall (P = 0.78). Body weight (BW) on day 74 was greater (P < 0.01) and final BW tended to be greater (P = 0.10) for FIN compared with REC. Cattle consuming FIN had greater (P < 0.01) average daily gain and increased (P < 0.01) gain:feed from days 0 to 74. There were no differences (P ≥ 0.31) in health outcomes. On day 74, FIN had greater (P = 0.04) fat thickness over the rump and rib but did not differ (P ≥ 0.52) on day 146. Carcasses of FIN had greater (P = 0.04) hot carcass weight with no difference (P ≥ 0.11) in ribeye area, 12th rib fat thickness, yield grade, or quality grade. There was no difference (P = 0.18) in liver abscess rate. There was a diet × day interaction for blood urea nitrogen (P = 0.02) such that concentration decreased from days 0 to 28 in both treatments, but was less on day 28 for FIN. Ruminal pH was greater on days 2 and 61 and rumination time was less from days 0 to 28 for FIN (diet × day interaction; P < 0.01). Overall, these results suggest that providing a finishing diet fed ad libitum to high-risk calves upon arrival may be a viable alternative to a low-energy receiving diet.

Crossbreeding beef sires to dairy cows: cow, feedlot, and carcass performance.

Genetic and reproductive advancements in the dairy industry, volatile milk markets, and beef packer restrictions on dairy carcasses have increased the popularity of crossbreeding beef sires to dairy cows in the United States. This observational study aimed to understand performance of dairy cows bred to beef sires and feedlot and carcass performance of crossbred beef × dairy cattle. For dairy cow performance, archived records from two dairies representing two successive lactations were evaluated in cows (Dairy A: n = 72/group; Dairy B: n = 456/group) representing 1) All Dairy, where previous sire type of conception was Holstein for both lactations, or 2) Beef on Dairy, where previous sire type of conception was Holstein for the preceding lactation and a beef breed for the subsequent lactation. For feedlot performance, closeout data from pens (n = 26/cattle type) of beef and beef × dairy steers and heifers were evaluated. For carcass performance, individual carcass data were compared between conventional beef (n = 966), beef × dairy (n = 518), and Holstein (n = 935) steers sampled across a variety of processing facilities, harvest lots, and geographical regions. Cow lactation performance was minimally impacted by sire type of previous conception. Cows conceived to beef sires exhibited a 2 to 3 d greater (P < 0.01) gestation length than cows conceived to Holstein sires. Beef × dairy cattle were not largely different in weight gain at the feedlot but exhibited 1-unit lesser (P < 0.01) dressing percentage than beef cattle. Beef × dairy carcasses possessed 18% lesser (P < 0.05) 12th rib fat thickness than beef cattle and 5% greater (P< 0.05) ribeye area than dairy cattle. Additionally, beef cattle produced nearly double (P < 0.05) the percentage of yield grade 4 carcasses produced by beef × dairy and Holstein cattle.

PSX-B-5 Effect of replacement of dry-rolled corn with un-processed rye on growth performance, efficiency of dietary net energy utilization, and carcass traits of finishing heifers

Abstract Continental × British beef heifers were used in a randomized complete block design experiment to evaluate the effects of replacing dry-rolled corn with unprocessed rye on growth performance, efficiency of dietary net energy (NE) utilization, and carcass trait responses in finishing heifers. Heifers (n = 56; 433 ± 34.0 kg) were transported 241 km from a regional sale barn to the Ruminant Nutrition Center in Brookings, SD. Heifers were blocked by weight grouping and then allotted to pens (n = 7 heifers/pen and 4 pens/treatment). Treatments included a finishing diet that contained 60% grain (DM basis) as dry-rolled corn (DRC) or unprocessed rye grain (RYE). On d 14, heifers were consuming the final diet and were implanted with 200 mg of trenbolone acetate and 28 mg of estradiol benzoate (Synovex-Plus, Zoetis, Parsippany, NJ). RYE heifers had decreased (P ≤ 0.01) final body weight, average daily gain, and gain efficiency; but tended (P = 0.08) to have a greater dry matter intake compared to DRC. RYE had decreased (P ≤ 0.01) observed dietary NE and decreased (P ≤ 0.01) observed-to-expected dietary NE ratio for maintenance and gain compared to DRC. Dressing percentage, 12th rib fat thickness, ribeye area, and the distribution of USDA yield and quality grades were not altered (P ≥ 0.12) by diet. Hot carcass weight, yield grade, estimated empty body fat (EBF), and body weight at 28% EBF decreased (P ≤ 0.02) and retail yield increased (P= 0.01) in RYE compared to DRC. These data indicate that unprocessed rye is a palatable feed ingredient for inclusion in finishing diets for beef cattle and that rye inclusion only minimally influences carcass quality. The feeding value of unprocessed rye is considerably less (21.4%) than that of dry-rolled corn using current standards and approximately 91% of the NE value of processed rye.

PSIV-15 Examining the relationship between breed type and anabolic implant protocols in performance in the feedlot, health, and temperament of beef steers

Abstract The purpose of this research was to compare anabolic implant protocols in feedlot steers of two different breed types. Sixty steers were stratified by weight and breed in a 2 x 3 factorial design examining two different breeds: Angus (AN; n = 38) or Santa Gertrudis influenced (SG; n = 22), and three implant strategies: no implant (CON; n = 20), a moderate implant protocol (d0 implant: Revalor-G, d56 implant: Revalor-IS, d112 implant: Revalor-S; MOD; n = 20), or a vigorous implant protocol (d0 implant: Revalor-IS, d56 implant: Revalor-S, d112 implant: Revalor-200; VIG; n = 20). Steers were randomly placed into pens equipped with GrowSafe® bunks and fed the same ration. Weight, chute score (CS), exit velocity, blood, temperature, hip height and 12th rib fat thickness were collected approximately every 28d over a 112d period. Over the 112 d, SG steers tended (P = 0.10) to gain more hip height than AN steers. Anabolic implant protocol influenced total gain with both VIG and MOD steers gaining more (P &amp;lt; 0.01) than CON. On d 0, SG steers had a higher (P &amp;lt; 0.01) CS compared to AN steers, with this being maintained through the course of the trial. There was also as a tendency for there to be a breed*treatment effect (P = 0.06) on d112, with SG-MOD having a higher (P = 0.04) CS than AN-VIG, and a tendency (P = 0.08) for SG-VIG to have a higher CS than AN-VIG. Moderate and VIG implant protocols may be a useful tool to increase performance in feedlot steers. However, this research did find that SG influenced steers may have a more excitable temperament, but implant protocol did not influence (P &amp;gt; 0.05) temperament.

274 Comparison of Two Ultrasound Systems for Estimation of Carcass Attributes in Feedlot Steers

Abstract Sixty-eight (68) crossbred steers were evaluated using two real-time, B-mode ultrasound units to estimate final carcass attributes. The cattle were ultrasounded at the West Texas A&amp;M research feedlot (Canyon, Texas) and carcass data was collected at the West Texas A&amp;M Meats Laboratory (Canyon, Texas) or Tyson Fresh Meats (Amarillo, Texas). Objectives of the study were 1) to compare ultrasound live animal data to carcass attributes at harvest 2) to evaluate the performance differences between the ALOKA 500 (ALK) and the EVO ultrasound units All ultrasound images were captured by the same Ultrasound Guidelines Council (UGC) certified technician with images being processed at the UltraInsights Laboratory (Pierce, Colorado). The correlations between 12th rib fat thickness of the carcass (FTC) and ultrasound (FTU) were 0.84 for the ALK and 0.85 for the EVO, with no differences being found between the two units (P = 0.15). Correlations between the 12-13th rib carcass ribeye area (REAC) and ultrasound ribeye area (REAU) were 0.69 for the ALK and 0.66 for the EVO. There was no difference in REAU size between the two units. Carcass marbling score (MS) and ultrasound intramuscular fat (IMFU) correlations were 0.78 for the ALK and 0.84 for the EVO. The IMF data were found to be different between the two units, with the EVO measuring a mean IMFU value of 6.03 and the ALK a value of 5.26 with the change of 0.77 being different (P &amp;lt; 0.01). It is concluded that both ultrasound units performed favorably when predicting FTC and marbling score but were not highly correlated for REAU. It was found that the predictions between the two units on FT and REA were the same, though the EVO was higher on both. The IMFU values between the ALK and EVO were different, with the EVO again predicting higher values.

PSIII-8 Sire breed differences for carcass attributes in feedlot steers using ultrasound technology

Abstract Live animal ultrasound measurements were taken on thirty-two feedlot steers and heifers for estimation of carcass endpoints including 12th rib fat thickness (FTU), ribeye area (REAU) and intramuscular fat (%FatU). Ultrasound measurements were collected by an inexperienced technician using an Aloka 500 ultrasound unit using Beef Image Analysis (BIA) software. The objective of the study was to evaluate carcass differences of four sire breed types including Angus (n = 11), Ultrablack (n = 6), Nelore (n = 6), Braunvieh (n = 1) and Angus X Nelore X Braunvieh hybrid (n = 8). Carcass data collected at harvest included 12th rib fat Thickness (FTC), Ribeye area (REAC), marbling score (MS), Yield Grade (YG), and Quality Grade (QG). The data were analyzed using SAS to determine breed effects. Means for FTU, FTC, REAU, REAC, %FatU and MS were 0.59 cm, 0.57 cm, 90.80 cm2, 83.53 cm2, 4.83%, and 483.75, respectively. There was no significant difference (P &amp;gt; 0.05) in YG and FT due to breed of sire. However, there was a trend for sire breed for ribeye area (P = 0.0728) for Angus X Nelore X Braunvieh cross and MS (P = 0.0786) for Ultrablack. Pearson correlation values between FTU and FTC, REAU and REAC, and %FatU and MS were 0.1217 (P = 0.05068), 0.3545 (P = .0465) and 0.5161 (P = 0.0025), respectively. These data suggest little differences existed in carcass attributes between various sire breeds out of a set of crossbred commercial cows.

PSXIII-14 Feedlot performance of Nellore cattle consuming diets containing high-moisture corn, calcium salts of fatty acids and organic minerals

Abstract This study, conducted at São Paulo University feedlot, Dracena, Brazil, was designed to evaluate the effect of adding either high-moisture corn, calcium salts of fatty acids (CSFA), or organic Zn+Cr on feedlot performance and carcass traits of Nellore cattle fed for 112 days. One-hundred fifty 18-mo-old Nellore bulls (404±24kg) were used and initially ranked, according to sires’ information, into groups of high and low EPD. Secondly, cattle were blocked by weight and randomly allocated to 30 pens (n = 5/pen), which were randomly assigned to the following 2x2 + 1 arrangement of treatments: Finely-ground corn, High-moisture corn, Finely-ground + CSFA, High-moisture corn + CSFA, and High-moisture corn + CSFA + Zn (90 ppm) and Cr (0.45 ppm). All diets contained 25 ppm of monensin. On day 0, one animal per pen was randomly selected to be slaughtered for baseline purposes. The replacement of finely-ground by high-moisture corn increased (P &amp;lt; 0.05) final BW (585 vs. 573 kg), ADG, HCW (321 kg vs. 315 kg) and decreased (P &amp;lt; 0.01) DMI (9.7 vs. 10.1 kg). Likewise, the addition of CSFA increased final BW, ADG (1.62 vs. 1.50 kg), and HCW (321 vs. 314 kg). The addition of Cr+Zn led to increased (P = 0.02) dressing percentage. No treatment effect was observed on final marbling (P &amp;gt; 0.55). It was observed interactions between treatments and EPD for G:F (P = 0.02) and final 12thrib-fat thickness (P = 0.03), where cattle from low-EPD groups needed high-moisture corn, CSFA and organic Zn+Cr to improve G:F and increase fat deposition; however, animals from high-EPD groups required only high-moisture corn. The adding of either high-moisture corn, CSFA, or organic Zn+Cr improved feedlot performance of Nellore cattle, and its effects seemed to be more effective in animals from low-EPD groups.

Effect of protein source and nonroughage NDF content in finishing diets of feedlot cattle fed free-choice hay on growth performance and carcass characteristics.

One-hundred twenty crossbreed steers (initial body weight (BW) 566 ± 42 kg) were used to evaluate the interaction of protein source (PS) and nonroughage NDF content (NRFC) in finishing diets of feedlot cattle fed free-choice hay on performance and carcass characteristics. Steers were stratified by BW and randomly assigned to 8 pens (2 × 2 factorial) and fed for 104 ± 10 d. Four dietary treatments were investigated: (1) distillers’ dry grains with solubles (DDGS) and a low NRFC (DLF), (2) DDGS and a high NRFC (DHF), (3) soybean meal (SBM) and a low NRFC (SLF), (4) SBM and a high NRFC (SHF). Free-choice grass hay and concentrates were offered in a different bunk. Data were analyzed as a randomized complete block design. Do to the confounded effect of PS and protein intake, a linear regression was used to evaluate the effect of protein intake in growth performance. For gain to feed ratio (G:F) an interaction tended to occur (P = 0.10) between PS and NRFC. Steers on the DHF treatment had a lower G:F compared with SLF and SHF. Feeding SBM increased (P = 0.05) final BW, tended to increase (P = 0.06) average daily gain (ADG), and decreased (P = 0.05) hay intake (HI) compared with steers fed DDGS. There was a positive association (P ˂ 0.01) of crude protein intake with ADG and FBW. Dietary NRFC did not change (P ≥ 0.3) final BW, ADG, DMI, and HI. Protein source did not affect (P ≥ 0.16) hot carcass weight (HCW), longissimus muscle (LM) area, dressing, 12th rib fat thickness, or marbling score (MS). No differences were detected between NRFC for dressing, HCW, LM area, or MS (P ≥ 0.18); but diets with greater NRFC decreased (P = 0.03) the 12th rib fat thickness. Steers in the SHF treatment presented the lesser kidney-pelvic-heart fat compared with the remaining treatments (PS × NRFC interaction, P = 0.04). Soybean meal inclusion/increase in protein intake improved growth performance of feedlot steers compared with DDGS, despite protein intake meet the protein requirement. Increasing the NRFC did not affect growth or HI but decreased feed efficiency of steers fed DDGS.

Effects of Revalor-XH, Revalor-200, and combination Revalor-IH/Revalor-200 on yearling beef heifer growth performance and carcass characteristics for 138 days on feed

The objective was to evaluate finishing heifer implant programs including a single noncoated implant (Revalor-200; REV-200); an initial noncoated implant (Revalor-IH) followed by another noncoated implant (Revalor-200; REV-IH/200) 80 d before slaughter; or a partially coated, delayed-release implant (Revalor-XH; REV-XH) on growth performance and carcass characteristics when heifers were fed for 138 d. A commercial feedlot trial used 1,728 crossbred heifers (initial BW = 412 kg; SD = 28.2 kg) to examine the 3 implant strategies. Only heifers implanted with REV-IH/200 were removed from their pen at re-implantation. Heifers implanted with REV-IH/200 had greater (P ≤ 0.05) carcass-adjusted final BW, calculated as hot carcass weight/DP, and G:F compared with heifers implanted with REV-200 or REV-XH. Treatment did not affect (P ≥ 0.24) final BW or ADG on a live basis. Heifers implanted with REV-IH/200 had greater (P ≤ 0.05) hot carcass weight and LM area compared with heifers implanted with REV-200 or REV-XH. Marbling score and 12th-rib fat thickness were not different (P ≥ 0.12) among implant treatments. Calculated YG were decreased (P = 0.05) for heifers implanted with REV-IH/200 compared with heifers implanted with REV-200, with a significant (P < 0.01) shift to a lower calculated YG distribution for heifers implanted with REV-IH/200 compared with REV-200 or REV-XH. Greater concentrations of trenbolone acetate and estradiol-17β improved carcass-adjusted G:F and hot carcass weight but did not significantly decrease marbling despite heifers having a lower calculated YG.

Fetal programming effects of early weaning on subsequent parity calf performance.

Mature Simmental × Angus cows [n = 147; body weight (BW) = 590 ± 72 kg] were used to evaluate the effects of early weaning on subsequent parity calf growth performance and carcass characteristics. Cows were assigned to one of two treatments based on their previous calf’s weaning age: early wean (EW) or conventional wean (CW). Dams assigned to the EW treatment had calves previously weaned at 88 ± 6 d of age, whereas dams assigned to the CW treatment had calves previously weaned at 185 ± 6 d of age. Cow BW and body condition scores (BCS) were monitored during the experiment. All cows were managed as a common group from the onset of the experiment at breeding until final pregnancy check of their next production cycle 462 d later. All calves in the experiment were managed as one group and weaned at a single time point, then feedlot performance and carcass characteristics were evaluated. Initial cow BW was different (P < 0.05), so it was included as a covariate for cow BW analysis. There was a treatment × date interaction (P < 0.01) for cow BW and cow BCS. Cow BW was consistently greater for the EW treatment from day 39 to the end of the experiment (P < 0.01). Cow BCS were not different at the onset of the experiment (P = 0.20), although after breeding and throughout lactation, BCS diverged between treatments and the EW treatment consistently had greater (P < 0.01) BCS than the CW treatment throughout the entire subsequent lactation. Gestation length was not different (P = 0.21) between treatments, yet calf birth BW was greater (P = 0.05) for the EW treatment. Neither artificially inseminated pregnancy percentage nor overall pregnancy percentage was different between treatments (P ≥ 0.61). Despite the greater birth BW for the EW treatment and no difference (P = 0.25) in milk production, weaning BW was not different (P = 0.50) between treatments. Feedlot performance measures were not different (P ≥ 0.13) between treatments, including feedlot arrival weight, final BW, average daily gain, dry matter intake, and gain to feed. Final carcass characteristics were not different (P ≥ 0.33) between treatments, including dressing percentage, hot carcass weight, LM area, 12th rib fat thickness, kidney, pelvic, heart fat percentage, USDA yield grade, and marbling score. Thus, early weaning resulted in improved BW and BCS of cows as well as increased birth BW of subsequent calf, although that did not transpire into differences in postnatal growth performance or carcass traits.

Effects of inorganic copper injection in beef cows at late gestation on fetal and postnatal growth, hematology and immune function of their progeny

To determine if Cu injection during late gestation can affect fetal and postnatal growth, hematology and immune function of progeny, 70 multiparous pregnant Angus cows, at 219 ± 15 d of gestation, were ranked by BW and BCS and randomly assigned to one of two treatments: Cu + (n = 35) in total 160 mg of Cu were administered subcutaneously in two moments (80 mg per moment) at 64 ± 15 d and 54 ± 15 d prepartum; and Cu- (n = 35), in total of 16 ml of sterile NaCl solution (9 g / l) were administered subcutaneously in two moments (8 ml per moment) at 64 ± 15 d and 54 ± 15 d prepartum. Calves from both treatments were weaned at 260 ± 15 d of age, male calves were separated from female calves and stockered on natural pastures until 690 ± 15 d of age, then placed into a feedlot for 104 d before slaughter. At the beginning of the experiment, cows Cu serum concentration was similar (P = 0.34) between treatments and these reflected a severe Cu deficiency (Cu + = 24.2 ± 1.5 μg/dl; Cu- = 22.2 ± 1.4 μg/dl). At calving, Cu serum concentration was greater (P < 0.01) in Cu + cows than Cu- cows. Copper serum concentration in calves from Cu + cows was greater at birth (P = 0.02) and 75 ± 15 d of age (P < 0.01) and tended (P = 0.07) to be greater at 160 ± 15 d of age compared to calves from Cu- cows. Calf BW at birth did not differ (P > 0.10) between treatments, however, calf BW adjusted at 75 d of age tended to be greater (P = 0.10) in calves from Cu + cows compared to calves from Cu- cows. Calf ADG from birth to 75 d of age was greater (P = 0.04) in calves from Cu + cows compared to calves from Cu- cows. Calf hematological parameters and titers of neutralizing antibodies against BHV-1 after primary and secondary vaccination against respiratory diseases did not differ (P > 0.10) between treatments. During finishing period, steers BW, 12th rib fat thickness and LM area were not affected (P > 0.10) by treatments. In summary, inorganic Cu injection during late gestation in Cu deficient beef cows allows to increase Cu serum concentration in calves from birth to 160 d of age. This event was associated with an increase in ADG and a tendency to increase BW during the first 75 days of life. After 75 days of age, any effect on the offspring performance was not observed.

275 Comparison of Revalor-xh with a revalor-ih/revalor-h/revalor-200 Re-implant Program on Feedlot Cattle

Abstract A commercial feedlot trial evaluated a 3-implant re-implant program using Revalor-IH/Revalor-H/Revalor-200 compared to a single Revalor-XH (200 mg TBA and 20 mg E2 partially coated) implant strategy on feedlot performance and carcass characteristics of calf fed heifers. Heifer calves (n = 1356) were purchased through time and blocked by source and arrival date, assigned randomly to pen within block, and pen assigned randomly to one of the two implant treatments. Heifers who received the 3-implant re-implant treatment were re-implanted on d67 with Revalor-H and on d137 with Revalor-200. Each block of cattle were harvested on the same study day, which averaged 215 days on feed. Performance data were analyzed as a randomized block design, with the blocking factor as source/arrival time being considered random. Implant strategy was analyzed as a fixed effect with pen (n = 20) as the experimental unit. On a live basis, heifers implanted with Revalor-XH had a tendency for a greater gain efficiency (P = 0.06) though there were no significant differences between implant treatments for final body weight, gain or intake (P ≥ 0.15). There were no significant differences between implant treatments for hot carcass weight, gain, or gain efficiency (P ≥ 0.29) on a carcass-adjust basis. Marbling score and 12th rib fat thickness were not impacted by implant treatment (P ≥ 0.80); however, there was an increase in LM area (P = 0.02) for heifers on the 3-implant re-implant treatment compared to the Revalor-XH implanted heifers. There was also a tendency for a greater calculated YG in heifers who received Revalor-XH (P = 0.07). Heifers fed for approximately 215 d with a single Revalor-XH implant performed similarly to heifers fed the same amount of days receiving a 3-implant re-implant strategy using Revalor-IH/H/200 combination.

Effect of Time of Supplementation and Supplement Delivery Method on Performance and Grazing Behavior of Backgrounded Beef Steers

Abstract Objectives were to investigate effects of supplement feeding time and delivery method on performance and grazing behavior of backgrounded steers. Crossbred steers (n = 109; 7 ± 1 m of age; BW = 245 ± 2.9 kg) were stratified by BW and source into 18 groups (6–7 steers per group), and randomly allotted to tall fescue pastures during 38- and 45-d treatment periods during fall of 2019 and 2020, respectively. Pasture groups were randomly assigned to 1 of 3 treatments (6 pastures per treatment): 1) steers hand-fed a commodity blend supplement at 0930 h (AM), 2) steers hand-fed supplement at 1330 h (PM), or 3) steers fed a commercially available self-fed supplement with an intake limiter (SELF). All treatments were formulated for as fed supplement intake of 1.5% BW. Pedometers were used to estimate animal activity level. Motion-sensing cameras were used in yr 1 to monitor feeder and waterer visits. Data were analyzed using the MIXED procedure in SAS with main effects of year, group, and treatment with pasture as a random effect. Treatment had no effect (P ≥ 0.13) on calf BW, flesh condition score, ADG, or ultrasound 12th rib fat thickness. Supplement DMI tended (P = 0.08) to be greater for SELF relative to hand-fed cattle, with yr 2 tending (P = 0.07) to be greater than yr 1. There was a treatment x year interaction (P = 0.04) for G:F with SELF and AM steers in yr 1 tending (P ≤ 0.09) to be greater than SELF in yr 2, with all other treatments being intermediate and not different. Self-fed cattle had greater (P ≤ 0.01) activity level and more (P = 0.01) visits to feeders relative to hand-fed treatments. Results indicate that performance of backgrounding steers was not greatly impacted by supplementation schedule or delivery method.

Effect of exogenous glucoamylase inclusion on in vitro fermentation and growth performance of feedlot steers fed a dry-rolled corn-based diet.

The objective was to evaluate the effect of adding an exogenous glucoamylase (GA) enzyme from the fungus Trichoderma reesei on in vitro fermentation, growth performance, and carcass characteristics of feedlot steers fed a dry-rolled corn (DRC)-based diet. Experiment 1 evaluated three levels of added enzyme (0, 0.24, and 0.72 GA enzyme units) and two corn particle sizes (CPS; 2 and 4 mm) in a factorial arrangement using a 7 h in vitro batch culture fermentation. Addition of GA increased (P < 0.01) in vitro dry matter disappearance by 13% and decreased final pH (P < 0.01). Molar proportion of propionate increased with GA inclusion (P < 0.01). A smaller CPS increased (P < 0.01) in vitro dry matter disappearance and total volatile fatty acid and decreased final pH (P < 0.01). A smaller CPS also decreased (P < 0.01) the molar proportion of acetate and increased (P < 0.01) the molar proportion of butyrate. In experiment 2, Angus × Simmental steers (n = 105; initial body weight [BW] = 329 ± 38 kg) were used to evaluate the inclusion of an exogenous GA on growth performance and carcass characteristics. Steers were fed a basal diet consisting of 60% DRC, 17.5% modified distillers grains with solubles, 12.5% corn silage, and 10% dry supplement on a dry matter basis for 136 d. Steers were blocked by weight and allotted to pens. Pens were randomly assigned to one of three treatments (5 pens/treatment): diet with no GA (CON), low inclusion of GA (122 enzyme units/kg dry matter [DM]; LGA), or high inclusion of GA (183 enzyme units/kg DM; HGA). Inclusion of GA did not affect (P ≥ 0.23) final BW, dry matter intake (DMI), or average daily gain (ADG) for the 136-d feeding period. Feed conversion was affected (P = 0.02) by treatment with steers fed HGA having ~8% greater G:F compared with LGA and CON. Treatment did not affect (P = 0.32) fecal starch. Inclusion of GA did not affect (P ≥ 0.19) carcass traits including hot carcass weight, 12th rib fat thickness, yield grade, longissimus muscle area, or marbling score. Overall, results suggest inclusion of exogenous GA enzyme increased in vitro dry matter disappearance in batch culture and improved feed conversion in steers fed 183 enzyme units/kg DM during the finishing phase.

Effect of Complete Replacement of Dry-Rolled Corn with Unprocessed Rye on Growth Performance, Efficiency of Dietary Net Energy Use, and Carcass Traits of Finishing Heifers

Simple SummaryCrop rotation diversity has many benefits for integrated crop–livestock production systems. Cereal rye deserves consideration for use as a component of an integrated crop–livestock system as rye is a multi-use crop than can be grazed, harvested for forage, or harvested for grain and straw. Previous research from this research center has indicated that processed rye (processed to a processing index of 78.8%) is a suitable ingredient (84% of the net energy value of dry-rolled corn) for use in cattle-finishing diets. Processing grains prior to feeding is proven to enhance growth performance in feedlot cattle. A major impediment to the use of rye in finishing diets is that the rye should be processed prior to feeding, and processing rye requires different equipment settings than for processing dry-rolled corn. The objectives of the present study were to evaluate the impact of the complete substitution of dry-rolled corn with unprocessed rye in finishing diets fed to feedlot heifers on growth performance, dietary net energy use, and carcass traits.Continental crossbred beef heifers were used in a randomized complete block design experiment to evaluate the effects of replacement of dry-rolled corn with unprocessed rye on the finishing-phase growth performance and efficiency of dietary net energy (NE) use. Fifty-six heifers (433 ± 34.0 kg) were transported 241 km from a sale barn in North Central South Dakota to the Ruminant Nutrition Center in Brookings, SD. Heifers were blocked by weight grouping and allotted to treatment pens (n = 7 heifers/pen and 4 pens/treatment). Treatments included a finishing diet that contained 60% grain (diet dry matter basis) as dry-rolled corn (DRC) or unprocessed rye grain (RYE). On study day 14, all heifers were consuming the final diet and were implanted with 200 mg of trenbolone acetate and 28 mg of estradiol benzoate (Synovex-Plus, Zoetis, Parsippany, NJ, USA). The RYE heifers had decreased (p ≤ 0.01) final body weight, average daily gain, and gain efficiency; however, they tended (p = 0.08) to have a greater dry matter intake compared to DRC heifers. RYE heifers had decreased (p ≤ 0.01) observed dietary NE and decreased (p ≤ 0.01) observed-to-expected dietary NE ratio for maintenance and gain compared to DRC heifers. The dressing percentage, 12th rib fat thickness, ribeye area, and the distribution of yield and quality grades were not altered (p ≥ 0.12) by dietary treatment. The hot carcass weight, calculated yield grade, estimated empty body fat (EBF), and body weight at 28% EBF decreased (p ≤ 0.02) and retail yield increased (p = 0.01) in RYE compared to DRC heifers. These data indicate that unprocessed rye is a palatable feed ingredient for inclusion in finishing diets for beef cattle and that rye inclusion only minimally influences the carcass quality grade. The feeding value of unprocessed rye is considerably less (21.4%) than that of dry-rolled corn using current standards and approximately 91% of the NE value of processed rye (processing index = 78.8%). Rye grain fed as processed or unprocessed grain has an NE value that is less than 90% of that of dry-rolled corn.

228 Effect of exogenous glucoamylase inclusion on in vitro digestion and feedlot cattle performance

Abstract The objective was to evaluate the effect of adding an exogenous glucoamylase (GA) enzyme to a finishing diet on in vitro digestion and performance of feedlot cattle. Experiment 1 evaluated 3 levels of added enzyme (0, 0.24, and 0.72 GA enzyme units) and 2 corn particle sizes (2 and 4 mm) in a 7 h in vitro batch culture fermentation. No interactions were observed (P &amp;gt; 0.10). Addition of GA increased (P &amp;lt; 0.01) in vitro dry matter disappearance by 9%. A smaller corn particle increased (P &amp;lt; 0.01) in vitro dry matter disappearance by 11%. In Experiment 2, Angus × Simmental steers (N = 105; BW = 340 ± 39 kg) were blocked by weight and assigned to 15 pens. Pens were randomly assigned to one of 3 treatments: control (CON) diet with no added enzymes, low inclusion of GA (122 enzyme units/kg DM; LGA), or high inclusion of GA (183 enzyme units/kg DM; HGA). Steers were fed a basal diet consisting of 60% dry rolled corn, 17.5% modified distillers grains with solubles, 12.5% corn silage, and 10% of a corn-based supplement on a DM basis for 139 d. Inclusion of GA did not affect (P ≥ 0.24) final BW, DMI, or ADG overall for the 136 d feeding period. Steers fed HGA had increased (P = 0.02) G:F compared with LGA and CON with least square means of 0.213, 0.194, and 0.197, respectively. Inclusion of GA did not affect (P ≥ 0.19) carcass traits including HCW, 12th rib fat thickness, yield grade, longissimus muscle area, or marbling score. Overall, results suggest inclusion of exogenous glucoamylase enzyme increased in vitro dry matter disappearance in batch culture and improved feed conversion of the finishing diet fed to feedlot steers at 0.381 g enzyme protein/kg DM.

PSIV-8 Effects of Late Gestation Calcium Salts of Fatty Acids Supplementation to Beef Cows on Offspring Finishing Phase Performance and Carcass Characteristics

Abstract The objective was to investigate the effects of late-gestation supplementation of Ca salts of fatty acids to beef cows on the finishing phase growth performance and carcass characteristics of the steer progeny. Ninety-six multiparous, fall-calving, Angus × Simmental cows (BW = 601 ± 76 kg) were stratified by BW, BCS, and age and randomly allotted into 8 endophyte-infected tall fescue pastures with 12 cows/pasture. Cows were supplemented with soybean hulls mixed with either 155 g/cow/d of EnerGII (SFA/MUFA; enriched with palmitic and oleic acids) or 80 g/cow/d of Prequel + 80 g/cow/d of Strata (PUFA; enriched with linoleic acid, EPA, and DHA) for the last 77 ± 6 d of gestation. Steer progeny (n = 70) were weaned at 186 ± 6 d of age and transported to feedlot. Steers were fed receiving diets for 3 weeks and transitioned to finishing diets and adapted to GrowSafe feed bunks for individual daily feed intake measurement. Steers were weighed every 28 d during the finishing phase. Steers were slaughtered at commercial abattoir at 432 ± 6 d of age, and carcass data were obtained from USDA camera grading system. Data were analyzed using the MIXED procedure of SAS, and repeated measure was used for BW. There were no differences (P ≥ 0.13) for BW, ADG, DMI, or feed conversion during the finishing phase. There was no differences (P ≥ 0.22) observed in hot carcass weight, dressing percentage, 12th rib fat thickness, yield grade, ribeye area, marbling score, or KPH fat. In conclusion, maternal supplementation of Ca salts of fatty acids during late gestation did not affect steer progeny growth performance during the finishing phase or carcass characteristics.