Trenbolone Acetate Research Articles

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.

Effect of zinc source and implant strategy on performance, carcass characteristics, and trace mineral concentrations in finishing feedlot steers.

Seventy-two Angus-crossbred steers (411 ± 16 kg) were assigned to a 2 × 3 factorial arrangement of treatments to examine the effects of blended Zn source supplementation on performance, carcass characteristics, and trace mineral parameters of steers administered no implant or a two-implant program. Factors included implant (IMP) strategies and Zn supplementation. During the 126-d study, steers were either not implanted (NoIMP) or implanted (IS/200; Elanco, Greenfield, IN) on days 0 (Component TE-IS; 80 mg trenbolone acetate + 16 mg estradiol) and 57 (Component TE-200; 200 mg trenbolone acetate + 20 mg estradiol). All steers were fed 70 mg Zn/kg on a dry matter (DM) basis from ZnSO4 + 30 mg Zn/kg DM from either basic ZnCl (Vistore Zn, Phibro Animal Health, Teaneck, NJ), Zn glycinate (Gemstone Zn, Phibro Animal Health), or ZnSO4 (ZnB, ZnG, or ZnS, respectively). Steers were blocked by weight into pens of 6 and fed a dry rolled corn-based diet via GrowSafe bunks (GrowSafe Systems Ltd.; Airdrie, AB, Canada). Data were analyzed using the Mixed Procedure of SAS, with fixed effects of Zn, IMP, and the interaction. Steer was the experimental unit (n = 12 steers/treatment). Liver and muscle collected on days −5, 14, 71, and 120 were analyzed for Zn concentration, and data were analyzed as repeated measures (repeated effect = Day). An IMP × Zn tendency (P = 0.07) was observed for day 126 body weight with no effects of Zn within NoIMP, whereas ZnS tended to be heavier than ZnB with ZnG intermediate within IS/200. Carcass-adjusted overall feed efficiency (G:F) was greatest for ZnS (Zn; P = 0.02). Implanted cattle had greater DM intake, G:F, and carcass-adjusted performance (P ≤ 0.01). Liver Zn concentrations were greater for IS/200 by day 120 (IMP × Day; P = 0.02). Within IS/200, ZnG tended to have greater muscle Zn than ZnS, whereas ZnB was intermediate (Zn × IMP; P = 0.09). No Zn or IMP × Zn (P ≥ 0.12) effects were observed for carcass data. However, IS/200 had greater hot carcass weight, dressing percentage, and ribeye area than NoIMP (P ≤ 0.001). These data suggest that implants improve growth and influence Zn metabolism. Future work should examine Zn sources and supplementation alongside implant strategies.

Determination of Eleven Veterinary Drugs in Chicken Meat and Liver

Brazil chicken production is around 13 million tons and about a third is exported to over 150 countries, placing Brazil as the world largest chicken meat producer, and therefore it is crucial to follow the legislation of all importer markets. This study conducted a survey by chance in 45 meat industries able to export. Therefore, 2580 chicken meat samples were collected and submitted to 11 analyte extraction and chromatographic verification of compliance in an accredited laboratory. Ten chemical residues (amoxicillin, bacitracin, colistin, dinitolmide + zoalene, spectinomycin, roxarsone, tiamulin, tylosin, trenbolone acetate and virginiamycin) were investigated in chicken meat and one (halofuginone hydrobromide) in chicken liver. The results showed that no compound exceeded the maximum residue limits established by seven legislations. All residue concentrations found were below the method quantification limit, thereby confirming the capability of Brazilian chicken meat industries in complying to foreign markets.

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.

Zinc supplementation strategies in feedlot heifers receiving an extended-release implant or an aggressive re-implant program.

Two hundred eight Angus-crossbred heifers (291 ± 23 kg) from four sources were used in a randomized complete block design. The objective of the study was to determine the effects of implant strategy and Zn supplementation on performance, carcass characteristics, muscle fiber diameter, and mineral status of heifers. Heifers were assigned to a 2 × 2 factorial study for 168 d, and factors included Zn and implant (IMP). Heifers were supplemented Zn (mg/kg dry matter [DM]; ZnSO4) at national (30; NRC) or industry (100; IND) recommendations. Implant strategies (Merck Animal Health, Madison, NJ) included extended-release Revalor-XH on day 0 (REV-XH; 20 mg estradiol + 200 mg trenbolone acetate) containing four uncoated pellets and six coated pellets or the uncoated implant Revalor-200 on day 0 and again on day 91 (REV-200; 20 mg estradiol + 200 mg trenbolone acetate). Heifers were blocked by weight within source to pens of five or six heifers per pen (nine pens per treatment). A corn silage-based diet was fed during the growing period (days 0–55) followed by transition to a corn-based finishing diet. Weights were taken consecutively on days −1/0, 55/56, and 167/168. Liver and muscle from the longissimus thoracis were collected from one heifer per pen on days −5, 14, 105, and 164. Data were analyzed via Mixed Procedure of SAS. Average daily gain (ADG) and liver mineral used Period as the repeated effect. Corresponding to periods of high hormone payout from each implant, days 0–28 and 91–120 ADG were greatest for REV-200, whereas REV-XH numerically peaked during days 56–91 (IMP × Period; P = 0.02). Day 91 IND body weight tended to be heavier (P = 0.06) and day 120 body weight was heavier (P = 0.05) than NRC heifers. No effect of Zn or IMP on final body weight was observed (P ≥ 0.21). Muscle fiber cross-sectional diameter on day 164 was greater (P = 0.05) in IND than NRC. Liver Mn concentrations decreased by day 14 regardless of implant, though days 105 and 164 concentrations were lesser for REV-200 than REV-XH (IMP × Period; P = 0.02). No effects of Zn, IMP, or the interaction were observed for carcass-adjusted gain to feed, days 0–168 DM intake, hot carcass weight, or ribeye area (P ≥ 0.11). The nominal differences in performance between implant strategies suggest that extended-release implants may be an effective implant strategy to replace re-implant programs in heifers, whereas the improved performance of heifers fed IND vs. NRC during times of peak hormone payout suggests a role for Zn in periods of rapid growth.

Preamble of Steroids Types and Presence of Androgenic Anabolic Steroids (AAS) in Humans and Animals

ABSTRACT: Steroids are the hormones; the main source of which are Adrenal glands and Gonads. Human body produced them naturally in a balanced quantity.They have mainly two types i.e. corticosteroids and anabolic-androgenic steroids (or in short form “anabolic”). Now-a-days these are artificially synthesized as drugs which are given to humans and animals. Anabolic steroids are naturally produced in body 4.0–9.0 mg per day. They are also used artificially to treat testosterone level in human body while athletes are using them to build their muscles. Athletes misuse this drug 10 to 1000 times more than the medical purpose. These drugs (Oestradiol benzoate,Progesterone, Testosterone propionate, Zeranol, Trenbolone acetate, and Melengestrol acetate) are given to animals 0.25 to 0.5 mg on daily routine for increasing their body mass or meat production which is causing serious health problems in meat consumers. Glucocorticoids and sex hormones found in animal milk naturally. While their recombinant hormone rBGH is using to increase milk production in animals has become a part of serious health concern in public. This review entails the brief description on steroids history, types, use by humans and animals and also the harmful effects on human health.

Effect of trenbolone acetate, melengestrol acetate, and ractopamine hydrochloride on the growth performance of beef cattle

The effect of trenbolone acetate + estradiol (TBA) implants, melengestrol acetate (MGA), and ractopamine hydrochloride + TBA (RAC + TBA) on growth performance and carcass characteristics in beef cattle (n = 680; 279 ± 10.1 kg) fed barley grain/corn silage was examined in a 4 yr study (four pens per treatment per year; 262 ± 8 d feeding period). In the first 2 yr, treatments were (1) control heifers (H-CON; no growth promoters), (2) TBA-implanted heifers (H-TBA), (3) MGA heifers (H-MGA), (4) control steers (S-CON; no growth promoters), and (5) TBA-implanted steers (S-TBA). A sixth treatment (6) RAC + TBA steers (RAC + TBA) was included in years 3 and 4. Overall dry matter intake (DMI) of heifers was increased (P &lt; 0.001) by TBA but not MGA. Compared with H-CONs, H-TBA had greater average daily gain (ADG) (P &lt; 0.001), gain to feed ratio (G/F) (P &lt; 0.001), and carcass weight (P &lt; 0.001), whereas S-TBA had increased ADG (P &lt; 0.001), G/F (P&lt; 0.001), and carcass weight (P &lt; 0.001) compared with S-CON. Compared with H-CON, H-MGA had increased (P &lt; 0.01) ADG, G/F, and carcass weight. The RAC + TBA had increased (P &lt; 0.01) ADG and carcass weight (3.2%) but not G/F or DMI compared with S-TBA. This 4 yr study showed a consistent positive impact of growth-enhancing technologies on the performance of Canadian feedlot cattle.

276 Evaluation of a Long-acting Growth-promoting Implant (Revalor-XS) as an Initial Implant in a Re-implant Program with a revalor-200 Terminal Implant in Feedlot Cattle: A Three-study Pooled Analysis

Abstract Data from three large-pen feedlot studies were pooled to evaluate use of a long-acting implant (Revalor-XS) as an initial implant in a re-implant program. The three studies consisted of 2,764 steers in 40 pens, with an initial body weight (BW) of 271 kg. Treatments consisted of Revalor-IS [80 mg trenbolone acetate (TBA), 16 mg estradiol (E2)] administered on arrival, followed by Revalor-200 (200 mg TBA, 20 mg E2) terminal implant (IS/200) or Revalor-XS (80 mg TBA, 16 mg E2 uncoated; 120 mg TBA, 24 mg E2 coated; 200 mg TBA, 40 mg E2 total) on arrival followed by Revalor-200 terminal implant (XS/200). Steers were fed to equal days-on-feed (DOF) within study and averaged 210 DOF. Steers within treatment were re-implanted at same DOF in two studies (Day 124 on average followed by an 81-day terminal implant window). In the third study, IS/200 steers were implanted on Day 120 and XS/200 steers on Day 140 of the 217-day study. Final BW averaged 635.6 and 638.3 kg for IS/200 and XS/200, respectively (P = 0.21). There were no differences (P &amp;gt; 0.26) in DMI, ADG and Gain:Feed between treatments. Hot carcass weight tended (P = 0.07) to be greater with XS/200 (412.7 kg) compared with IS/200 (409.1 kg). Ribeye area was greater (P &amp;lt; 0.01) and fat thickness tended (P = 0.06) to be lower with XS/200 compared with IS/200. Distributions of USDA quality grades were not affected (P = 0.26) by treatment. Distributions of USDA yield grades (YG) were affected (P = 0.01) by treatment with a shift toward more YG 1 and 2 carcasses with XS/200 and more YG 4 and 5 carcasses with IS/200. This analysis indicates that using Revalor-XS as an initial implant leads to greater carcass weight and ribeye area and lower YG when compared with Revalor-IS.

273 Effect of Feedlot Implant Dose and Terminal Window Timing on Heifer Performance and Carcass Characteristics

Abstract Feedlot heifers (n = 3,778; initial BW = 310 kg; SD = 28 kg) were utilized in a 3 x 2 factorial arrangement (9 pens/treatment) to investigate increasing implant dose and terminal window (TW) timing on growth and carcass merit. Component with Tylan® implant dose treatments were 1. Initial TE-IH [80 mg trenbolone acetate (TBA), 8 mg estradiol (E2)] and terminal TE-H (140 mg TBA, 14 mg E2; IH/H), 2. Initial TE-IH and terminal TE-200 (200 mg TBA, 20 mg E2; IH/200), or 3. Initial TE-200 and terminal TE-200 (200/200). Heifers were fed 171 d with terminal implant administered 100 or 60 d prior to slaughter; initial implant window was inverse (71 or 111 d) to TW. Data were analyzed as a mixed model with block included as a random effect. No significant dose x TW interactions occurred for growth or carcass characteristics (P ≥ 0.06) therefore, main effects are presented. Terminal window treatments resulted in similar (P &amp;gt; 0.25) live performance. Heifers reimplanted 60 d prior to slaughter had improved (P &amp;lt; 0.05) marbling score and lower YG2 carcasses. Final weight, gain, HCW, yield, and LM area increased (linear; P &amp;lt; 0.05), while marbling score and fat thickness decreased (linear; P &amp;lt; 0.05) with increasing heifer implant dose. Heifers implanted with IH/200 had lower (P &amp;lt; 0.05) DMI compared to IH/H. IH/200 and 200/200 had improved (+2.1%; P &amp;lt; 0.05) efficiency compared to IH/H. HCW for 200/200 was +3.2 and 5.5 kg greater than IH/200 and IH/H, respectively. 200/200 were leaner with +7.4% YG 1&amp;2 and -5.4% YG 4&amp;5, but -8.5% Prime &amp; Choice carcass compared to IH/H. Shortening TW from 100 to 60 d prior to slaughter did not alter growth performance. Increased implant dose in heifers improved gain, efficiency, HCW and yield with some quality grade considerations.

116 Effect of Coated and Non-coated Steroidal Implants on Growth Performance, Dietary Net Energy Utilization and Carcass Traits of Feedlot Finishing Steers

Abstract Maine-Anjou x Angus steers (n = 156, initial BW 366 ± 37.2 kg) were used in a 132-d finishing experiment at the Ruminant Nutrition Center in Brookings, SD. Steers were weighed on two consecutive days and assigned into 5 weight blocks. Within each weight block steers were randomly assigned to two implant types (equal steroidal hormone dose; both from Zoetis, Parsippany, NJ) and two dietary treatments in a 2 × 2 factorial arrangement. Implant treatments consisted of 1) Coated implant, 200 mg trenbolone acetate (TBA), 28 mg estradiol benzoate (EB) (Synovex ONE Feedlot, ONE) or 2) Non-coated implant, 200 mg TBA, 28 mg EB (Synovex PLUS; PLUS), placed in the left ear. Dietary treatments were 1) 15% or 2) 30% corn silage (DM basis). No interaction between implant and corn silage inclusion was observed for carcass-adjusted (hot carcass weight / 0.63) growth performance, dietary net energy (NE) utilization or carcass traits (P ≥ 0.16). Bunks were managed using a slick bunk approach and all diets contained (DM basis) 33 mg/kg monensin sodium. Implant status was checked on d 28 by a single trained evaluator; steers with missing implants were immediately re-implanted. There was no difference in carcass-adjusted growth performance between implants (P ≥ 0.85). There were no differences in observed NE or the observed-to-expected ratio of NE for either growth or maintenance (P ≥ 0.90). No differences were observed for dressing percent, hot carcass weight, ribeye area, or rib fat (P ≥ 0.22). Marbling differed between implant treatments (433 to 466 ± 8.7; P = 0.01) for PLUS and ONE respectively. Implanting cattle with a coated implant had no detrimental effect on growth performance or carcass traits, but it did increase marbling scores.

Effects of Dried Distillers’ Grains Cube Supplementation for Steers Grazing Introduced Pastures on Animal Performance and Forage Production

Abstract We evaluated the effects of supplementing dried distillers’ grains cubes (DDGS) and re-implantation of steers (n = 149; BW = 238 ± 13.8 kg) grazing tall fescue (Festuca arundinacea)/bermudagrass (Cynodon dactylon) pastures (n = 9 pastures, 7.2 ± 2.90 ha) from 14 April to 17 September 2020 (n = 155 d) in a split-plot design on steer performance and forage production. Main plot supplemental treatments (n = 3 pastures/treatment) included 1) Fertilized Control (FC), no supplementation on fertilized pastures (112 kg N/ha); 2) Fertilized Supplement (FS), supplemental DDGS fed at 2.9 kg 3-d/wk on fertilized pastures; and 3) Supplement (S), supplemented DDGS at 0.75% BW/d on unfertilized pastures prorated for 5-d/wk feeding. Steers were previously implanted during receiving with 40 mg trenbolone acetate and 8 mg estradiol (REV-G; Revalor G, Merck Animal Health). On July 7, steers in each pasture were randomly assigned to one of three re-implant treatments: 1) no re-implant; 2) REV-G; or 3) 200 mg progesterone and 20 mg estradiol (Synovex S, Zoetis Animal Health). Steers in FS and S gained more (P &amp;lt; 0.01) than FC throughout the trial and final BW was greater (P &amp;lt; 0.01) for FS and S compared with FC. Unexpectedly, re-implanting had no effect on ADG (P = 0.57) or BW (P = 0.34), but statistical power may be lacking. Supplemental efficiency was greater in the late summer for FS (P = 0.05) compared to S. Fertilizing pastures in FS and FC did not affect biomass (P = 0.39), however, CP was increased (P = 0.01) and acid and neutral detergent fibers tended to decrease (P = 0.06) relative to S in the early summer (April, May, June, and July), but did not differ in late summer (August and September). Based upon our analysis, DDGS is a suitable supplement and can replace N fertilizer for steers grazing introduced pastures.

Does a single adjustment in the meat standards Australia beef grading model cater for different hormonal growth promotant formulations?

This paper investigated whether a single Hormonal Growth Promotant (HGP) adjustment in the Meat Standards Australia (MSA) beef grading model adequately predicted consumer eating quality of beef from cattle treated with different HGP formulations. This paper used consumer sensory data from two experiments. In experiment one, a total of 300 steers were allocated to three treatments; control (CON-100-F), 100 day oestradiol only HGP (OES-100-F), or a combination of trenbolone acetate and oestradiol HGP (TBA+OES-100-F) and finished in a feedlot for 73 days. In experiment two, a total of 200 steers were allocated either control or 400 day oestradiol only HGP treatments and finished on pasture for 389 days. Steers were slaughtered by finishing regime and carcass traits recorded. The anterior and posterior portions of the m. longissimus lumborum (LL-A and LL-P, respectively) and m. gluteus medius (GM) were collected and aged for five or 35 days. Grilled meat samples were scored for tenderness, juiciness, liking of flavour and overall acceptability using untrained consumers. Sensory scores were weighted by 0.3. 0.1, 0.3 and 0.3, respectively and summed to calculate a meat quality (MQ4) score. Residual MQ4 scores were calculated (observed MQ4 minus the predicted MQ4 score). The MSA model accounts for varied impacts of different HGPs on eating quality through a single HGP adjustment, and indirect impacts on carcass traits. For the majority of the HGP treatment samples, the residual MQ4 scores were not different to zero (5/18), or were positive i.e. the MSA model under-predicted these samples (11/18). Under-prediction was predominately for 35 day aged (7/9) and GM HGP treatment samples (6/6) and was considered low, with the majority less than ±5 MQ4 units. Under-prediction could be considered as advantageous through providing an additional safeguard to protect the interests of the consumers, rather than if the model had over-predicted and resulted in a more negative eating quality experience than expected. Some over-prediction was observed in the CON-100-F and TBA+OES-100-F treatment samples, which may be due to factors such as genetic variation and/or production environment. Minimal bias was observed when residual MQ4 was regressed against predicted MQ4 for the range of feeding regimes, muscles, ageing periods and treatment groups. This study showed that a single HGP adjustment in the MSA beef grading model, combined with the indirect effects of the different HGP formulations on carcass traits, provided a reasonable prediction of meat eating quality for different HGP formulations.

Influences of implant hormone strategy on growth performance of calf-fed Holstein steers fed in excess of 300 days

The objective was to compare the effects of 4 implant management strategies involving long-duration implants on growth performance and dietary NE use of calf-fed Holstein steers. A total of 192 calves were used in a 335-d experiment. Treatments were as follows: S1S1 = Synovex ONE (200 mg of trenbolone acetate and 28 mg of estradiol benzoate; Zoetis Animal Health, New York, NY) on arrival and Synovex ONE on d 168; S1SP = Synovex ONE on arrival and Synovex Plus (200 mg of trenbolone acetate and 28 mg of estradiol benzoate; Zoetis Animal Health) on d 224; SCE = Synovex C (100 mg of progesterone and 28 mg of estradiol benzoate; Zoetis Animal Health) on arrival and Encore (43.9 mg of estradiol; Elanco Animal Health, Greenfield, IN) on d 112; and SCS1 = Synovex C on arrival and Synovex ONE on d 112. Steers implanted with Synovex ONE on arrival had greater ( P < 0.01) ADG, G:F, and performance-estimated NE g (peNE g ) than those receiving a Synovex C implant. From d 112 to 224, steers in the SCS1 group had greater ( P < 0.01) ADG than steers in the SCE group. Differences in ADG between SCE and SCS1 were not appreciable ( P = 0.14) during the final 111-d period of the study. Cattle in the S1S1 group had greater ( P < 0.01) ADG and DMI than cattle in the S1SP group during the second 112-d period but decreased ( P < 0.01) G:F and peNE g during the final 111-d period. Implant strategies that incorporate long-acting implants to avoid terminal implantation when animals have greater days on feed did not improve calf-fed Holstein steer growth performance. Indeed, using a noncoated hormonal implant during the late finishing phase (implantation at 224 d on feed) increased overall peNE g , representing greater efficiency on cattle growth performance.

The Impact of Polyamine Precursors, Polyamines, and Steroid Hormones on Temporal Messenger RNA Abundance in Bovine Satellite Cells Induced to Differentiate.

Simple SummaryIn the U.S., approximately 90% of all cattle on feed receive an anabolic implant at some point during production. Despite the widespread use, how they operate to increase growth of cattle remains unknown. Polyamines are amino acid derivatives, which are potent growth stimulants, produced through the polyamine biosynthetic pathway. Emerging research suggests that the hormones in anabolic implants interact with the polyamine biosynthetic pathway. The purpose of this research was to investigate the effects of steroidal hormones, polyamine precursors, and polyamines on mRNA abundance of bovine satellite cells, muscle precursor cells. The results from this study suggest that polyamine precursors and polyamines alter transcription factors involved in induction of differentiation of bovine satellite cells and the polyamine biosynthetic pathway, while the hormones in anabolic implants alter genes involved in the polyamine biosynthetic pathway. These results mean that polyamines may impact differentiation of bovine satellite cells, ultimately affecting growth of cattle.Emerging research suggests that hormones found in anabolic implants interact with polyamine biosynthesis. The objective of this study was to determine the effects of steroidal hormones, polyamines and polyamine precursors on bovine satellite cell (BSC) differentiation and polyamine biosynthesis temporally. Primary BSCs were induced to differentiate in 3% horse serum (CON) and treated with 10 nM trenbolone acetate (TBA), 10 nM estradiol (E2), 10 nM TBA and 10 nM E2, 10 mM methionine, 8 mM ornithine, 2 mM putrescine, 1.5 mM spermidine, or 0.5 mM spermine. Total mRNA was isolated 0, 2, 4, 8, 12, 24, and 48 h post-treatment. Abundance of mRNA for genes associated with induction of BSC differentiation: paired box transcription factor 7, myogenic factor 5, and myogenic differentiation factor 1 and genes in the polyamine biosynthesis pathway: ornithine decarboxylase and S-adenosylmethionine—were analyzed. Overall, steroidal hormones did not impact (p > 0.05) mRNA abundance of genes involved in BSC differentiation, but did alter (p = 0.04) abundance of genes involved in polyamine biosynthesis. Polyamine precursors influenced (p < 0.05) mRNA of genes involved in BSC differentiation. These results indicate that polyamine precursors and polyamines impact BSC differentiation and abundance of mRNA involved in polyamine biosynthesis, while steroidal hormones altered the mRNA involved in polyamine biosynthesis.

Effects of Corn Silage Inclusion Level and Type of Anabolic Implant on Animal Growth Performance, Apparent Total Tract Digestibility, Beef Production per Hectare, and Carcass Characteristics of Finishing Steers.

Simple SummaryCorn silage has long been a staple feed ingredient in cattle diets throughout the Midwest region of the United States. The most recent Feedlot Consulting Nutritionist Survey indicated that corn silage was the primary and secondary roughage source used in finishing diets by 37.5% of respondents. Using the entirety of the corn plant for feed allows for producers to quickly harvest feed tonnage. A common belief is that one should only include enough corn silage in a finishing ration to maintain rumen health. However, previous research conducted by our research group suggested that feeding increased levels of corn silage could increase the quantity of beef produced per hectare of cropland. Another aspect to consider when finishing cattle is implant type. Today a wide variety of implants are available, including polymer barrier coated and non-coated implants. Coated implants can provide an extended release of trenbolone acetate and estradiol for up to 200 days post-implantation. The objectives of the current study were to determine the influence of corn silage inclusion level and terminal implant type on animal growth performance, apparent total tract digestibility, carcass traits, and beef production per hectare of cropland in finishing steers harvested at common rib fat thickness.Maine-Anjou × Angus cross-bred steers (n = 156 steers; initial body weight (BW) 366 ± 37.2 kg) were used in a 132 d finishing study conducted at the Ruminant Nutrition Center (RNC) in Brookings, SD. Steers were blocked by weight (n = 5 BW blocks) and randomly assigned to an implant and dietary treatment of a randomized complete block design with each pen containing seven to eight steers (n = 20 pens). Dietary treatments consisted of (1) 15% (CS15) or (2) 30% corn silage (CS30) where corn silage displaced corn grain in the diet. Steers received one of two implants (both from Zoetis, Parsippany, NJ) containing equal doses of trenbolone acetate (TBA) and estradiol benzoate (EB): (1) Synovex PLUS (non-coated implant; 200 mg TBA and 28 mg EB; PLUS) or (2) Synovex ONE Feedlot (coated implant; 200 mg TBA and 28 mg EB; ONE-F). Bunks were managed using a slick bunk approach, and all diets contained dry matter (DM) basis 33 mg/kg monensin sodium. All steers were offered ad libitum access to feed, and feeding occurred twice daily in equal portions. There was no interaction between the implant and dietary treatment for any variables measured (p ≥ 0.08). Carcass-adjusted basis final BW, average daily gain (ADG), and grain to feed (G:F) were increased (p ≤ 0.02) by 2.2%, 6.5%, and 7.2%, respectively, for CS15. Observed net energy (NE) and the ratio of observed-to-expected NE for maintenance and gain was not influenced (p ≥ 0.15) by silage inclusion treatment. Beef production per hectare was not impacted (p ≥ 0.13) by corn silage inclusion level. Fecal output was increased, and digestibility coefficients for dry matter, organic matter, and crude protein were decreased in CS30 (p ≤ 0.03). Dressing percent and hot carcass weight (HCW) were greater (p ≤ 0.02) in CS15. Implant type did not influence any traits measured (p ≥ 0.14) except for marbling. Marbling was decreased for PLUS (433 vs. 466 ± 17.5; p = 0.02) compared to ONE-F steers. Similar beef produced per hectare of crop land-based upon silage feeding level means producers can feed greater inclusions of corn silage to finishing cattle without impacting carcass quality or beef production; implanting with a coated implant had no detrimental effects to growth performance but increases marbling scores.

Evaluation of coated steroidal combination implants on feedlot performance and carcass characteristics of beef heifers fed for constant or varying days on feed

Two experiments evaluated the effects of delayed, long-lasting implant strategies for finishing heifers fed for constant or varying days on feed. In Exp. 1, heifers (n = 500; initial BW = 280 ± 21 kg) were allotted randomly to 1 of 5 treatments, including no implant (CON), Revalor-XH on d 1 (XH), Revalor-200 on d 1 (E200), Revalor-XR on d 1 (XR), or Revalor-200 on d 70 (D200). All implants contained 200 mg of trenbolone acetate and 20 mg of estradiol. In Exp. 2, 720 heifers (initial BW = 281 ± 10 kg) were assigned randomly to treatments in a 3 × 4 factorial arrangement, with 3 implant treatments [no implant (NCON), Revalor-200 on d 1 and 100 (PCON), or Revalor-XH on d 1 (XH)] and 4 serial slaughter dates following 151, 165, 179, or 193 d on feed. In Exp. 1, implanted heifers were heavier, gained more, and were more efficient (P ≤ 0.03) compared with CON heifers, but no differences were observed among implant treatments (P ≥ 0.21) over the 198-d finishing trial. Implanted heifers had greater hot carcass weight but lower marbling scores compared with CON heifers (P ≤ 0.04). In Exp. 2, there were no serial slaughter × implant treatment interactions for growth performance (P ≥ 0.23) or carcass characteristics (P ≥ 0.31). Final BW, fat thickness, and numerical YG increased linearly (P < 0.01), whereas ADG (P = 0.01) and G:F (P = 0.02) decreased linearly, with increasing days on feed. Hot carcass weight was increased by implanting strategy and increasing days on feed, but aggressive initial implants did not improve performance.

Effects of ruminally-protected lysine and Megasphaera elsdenii on performance and carcass characteristics of finishing cattle

Ractopamine hydrochloride is a β-adrenergic agonist (BAA) commonly added to cattle finishing diets that redirects nutrients from fat deposition to protein synthesis and muscle growth. Physiological conditions established by BAA suggests that cattle fed diets containing BAA would have greater requirements for dietary protein to sustain BAA-induced accretion of lean tissue. Three hundred and eighty-four crossbred steers (413 ± 29.2 kg initial body weight) were used in a finishing trial to evaluate effects of ruminally-protected lysine (RPL) supplementation on performance and carcass characteristics of beef steers. Treatments were (2 × 4 factorial) 0, 20, 40, or 60 g/animal daily of SafeGain (i.e., approximately 0, 0.6, 1.2, or 1.8 g of lysine/kg diet dry matter based on an assumed daily feed intake of 10 kg per animal) in conjunction with a BAA (33 mg/kg diet dry matter basis) during the last 42 days on feed (112 days finishing period); and two step-up regimens: traditional 21-day step-up or an accelerated 12-day step-up with an oral dose of Megasphaera elsdenii probiotic (M.e.). Steers were blocked by weight; randomly assigned to treatments; implanted with 200 mg trenbolone acetate, 20 mg estradiol USP, and 29 mg tylosin; and allocated within blocks to 64 concrete-surfaced pens containing 6 steers per pen. A basal diet (dry matter basis) of 688.7 g/kg steam-flaked corn, 200 g/kg corn gluten feed, 70 g/kg alfalfa hay, and 19.1 g/kg vitamin and mineral supplement was fed ad libitum once daily. Ruminally-protected lysine was supplemented only during the BAA administration period, which comprised the last 42 days on feed. At the end of the finishing period, pens of cattle were weighed and then transported to a commercial abattoir. Harvest order, hot carcass weight, and liver abscess incidence and severity were evaluated the day of harvest. Longissimus muscle area, back fat, marbling score, USDA Yield Grade and USDA Quality Grade data were collected following a 36-hour refrigeration period. There were no effects of RPL supplementation or M.e. on average daily gain (P > 0.63), dry matter intake (P > 0.45), or feed efficiency (P > 0.81) of finishing steers; but liver abscess incidence was increased with RPL supplementation (P < 0.05; 28.3, 39.0, 46.9 and 39.4 % for cattle fed 0, 20, 40 and 60 g/animal daily of RPL, respectively). An interaction between RPL and M.e. was observed for hot carcass weight (P = 0.01). Dosing cattle with M.e. with an accelerated transition period decreased marbling score (P = 0.03) and yielded a lower percentage of carcasses grading Choice (P = 0.03) than those traditionally adapted. No other effects of M.e. or RPL were observed for carcass characteristics (P> 0.10). Thus, supplementation of RPL in conjunction with ractopamine hydrochloride yielded no benefits during feedlot finishing; however, an accelerated step-up program with M.e. yielded finishing performance comparable to that of traditionally-adapted cattle.

Ractopamine and Other Growth-Promoting Compounds in Beef Cattle Operations: Fate and Transport in Feedlot Pens and Adjacent Environments.

The current study represents a comprehensive investigation of the occurrence and fates of trenbolone acetate (TBA) and metabolites 17α-trenbolone (17α-TBOH), 17β-TBOH, and trendione (TBO); melengesterol acetate (MGA); and the less commonly studied β-andrenergic agonist ractopamine (RAC) in two 8 month cattle feeding trials and simulated rainfall runoff experiments. Cattle were administered TBA, MGA, or RAC, and their residues were measured in fresh feces, pen floor material, and simulated rainfall runoff from pen floor surfaces and manure-amended pasture. Concentrations of RAC ranged from 3600 ng g-1, dry weight (dw), in pen floor to 58 000 ng g-1 in fresh feces and were, on average, observed at 3-4 orders of magnitude greater than those of TBA and MGA. RAC persisted in pen floors (manure t1/2 = 18-49 days), and contamination of adjacent sites was observed, likely via transport of windblown particulates. Concentrations in runoff water from pen floors extrapolated to larger-scale commercial feedlots revealed that a single rainfall event could result in mobilization of gram quantities of RAC. This is the first report of RAC occurrence and fate in cattle feedlot environments, and will help understand the risks posed by this chemical and inform appropriate manure-management practices.

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.

186 Hormone content of anabolic implants differentially affects plasma and liver trace mineral concentrations

Abstract Forty-eight commercial Angus steers (327 ± 25 kg) were utilized to determine effects of varying implant hormone composition on liver and plasma trace mineral concentrations. Implant (IMP) treatments (n = 12/treatment) included: no implant (CON), estradiol (E2; Compudose; 25.7 mg estradiol; Elanco Animal Health; Greenfield, IN), trenbolone acetate (TBA; Finaplix H; 200 mg trenbolone acetate; Merck Animal Health; Madison, NJ), and a combination of estradiol and trenbolone acetate (ETBA Revalor-S; 24 mg estradiol + 120 mg trenbolone acetate; Merck Animal Health). Cattle were fed forage-based step up rations throughout the sampling period. Plasma samples were collected on d 0, 2, 10 and 30, with liver biopsies collected on d 2 and 10. Data were analyzed with ProcMixed of SAS with fixed effect of IMP. Contrast statements for each treatment vs CON were developed. Plasma trace mineral analysis utilized repeated measures (repeated effect = day). No IMP × Day effects (P ≥ 0.18) on plasma trace mineral were observed. Day 2 liver Zn and Cu and d 10 liver Mn were lesser (P ≤ 0.04) for TBA implanted steers than CON and d 2 liver Mn tended to be lesser (P = 0.06). The Mn response may reflect changes in protein metabolism due to TBA. However, E2 and ETBA tended to have greater (P ≤ 0.07) d 10 liver Fe concentrations than CON while plasma Fe was unaffected (P ≥ 0.75) by E2, TBA, or ETBA. Both d 2 liver and plasma Zn were lesser for ETBA than CON (P ≤ 0.04) likely driven by the TBA in the implant. Implant contrasts did not affect (P ≥ 0.13) other plasma or liver trace mineral concentrations. These data indicate implant strategies, and thus hormones differentially influence trace mineral metabolism in feedlot steers, which may have implications for diet formulation.