The aim of this study was to examine the impact of daily calcium propionate (CaPr) supplementation (0 or 20 g/calf) on growth performance, dietary energetics, body fat reserves, serum metabolites, and hematological responses in high-risk beef calves fed diets with varying (50, 60, or 70%) concentrate (CON) levels. In addition, a cost/income analysis of CaPr supplementation was carried out. Forty-eight crossbred bull calves (152.8 ± 1.56 kg body weight and 5.5 months of age) were involved in a fully randomized experimental design employing a 2 × 3 factorial arrangement of treatments. Calves were allocated (n = 8 per treatment) to individual pens (3.14 × 5.25 m) and were subjected to one of the following treatments during 42 d: No CaPr supplementation in diets containing 50, 60, or 70% CON (NoCaPr + 50, NoCaPr + 60, NoCaPr + 70, respectively) or daily CaPr supplementation dosed at 20 g/calf in diets containing 50, 60, or 70% CON (20CaPr + 50, 20CaPr + 60, 20CaPr + 70, respectively). Non-supplemented calves exhibited decreased dry matter intake (DMI) with increasing CON levels in their diets, while CaPr-supplemented calves displayed the opposite effect (interaction, p = 0.04). In calves fed a lower-CON diet (50%), those supplemented with CaPr showed greater average daily gain (ADG, 20.2%, p = 0.05) and lower DMI (2.2%, p = 0.03), resulting in improved ADG/DMI ratio, dietary energy, and energy retention (24.6, 14.4, and 18%, p < 0.05). These effects diminished when calves received diets with 60 or 70% CON but led to a 14.2% increase in rump fat thickness (p = 0.04). Only in non-supplemented CaPr calves, increasing the level of CON from 50 to 70% in the diet increased ADG (21.2%), decreased DMI (2.2%), and improved the ADG/DMI ratio (22.7%), with no impact on dietary net energy utilization. Non-supplemented calves exhibited an increase in lymphocytes as CON levels rose in their diets, whereas CaPr-supplemented calves showed the opposite effect (interaction, p = 0.05). Supplementation of CaPr decreased total protein (TP, p = 0.03) and albumin (ALB, p < 0.01) serum concentrations, with lower concentrations observed in 20CaPr + 50. CaPr supplementation reduced (p = 0.01) total cholesterol (TCHO) levels. An interaction between CaPr and CON level (p = 0.02) was observed since TCHO levels remained consistently low at higher CON levels. Glucose was decreased with increasing levels of CON (p = 0.02) but not (p = 0.85) for CaPr-supplemented calves. NoCaPr + 50 and NoCaPr + 70 increased (p = 0.05) ALB concentration. Gamma glutamyltransferase levels increased (p = 0.05) with increasing CON levels irrespective of CaPr supplementation. Comparing the profit within the same CON level in the diet, CaPr treatments yielded higher income, with the largest difference in profit observed when CaPr was supplemented at 50% CON level (USD 29 more/calf). In conclusion, CaPr supplementation proves to be an effective strategy for enhancing growth performance and dietary energy among high-risk beef calves, resulting in greater economic returns. The groups that received CaPr demonstrated superior profitability, particularly in calves fed diets with lower CON levels. Under the conditions in which this experiment was carried out, the optimal response occurred when the low-CON diet (50%) was supplemented with CaPr.

Energy availability is a critical point in newly received calves. This study was conducted to examine the effect of daily calcium propionate (CaPr), chromium-methionine (Cr-Met), or CaPr plus Cr-Met (CaPr + Cr-Met) supplementation on growth performance, dietary energetics, body fat reserves, serum metabolites, and hematological responses in high-risk beef calves. Forty-eight crossbred bull calves (148.7 ± 2.05 kg body weight) were involved in a fully randomized experimental design. Calves which were individually pen allocated (12 repetitions/treatment) were subjected to one of the following treatments daily over 56 d: (1) Control, no additives; (2) CaPr, 19 g CaPr; (3) Cr-Met, 4 g Cr-Met; and (4) CaPr + Cr-Met, 19 g CaPr plus 4 g Cr-Met. Compared to controls, feed additive supplementation alone or in combination did not modify dry matter intake (DMI), but increased average daily gain (ADG), improving the ADG/DMI ratio. However, no synergistic effect on dietary energy utilization efficiency was observed with the combination of CaPr and Cr-Met; individual supplementation proved more effective. Because of the magnitude of the effects of Cr-Met on the efficiency of dietary energy utilization, this resulted in an increase (p < 0.05) in rump fat thickness (RFT). The supplementation of CaPr + Cr-Met decreased ALB/GLO ratio, MPV, and RBC, but increased TCHO, GLU, and MCH (p > 0.05). It is concluded that supplementation with CaPr or Cr-Met independently is an effective strategy to improve growth performance, energy utilization and retention, and body fat reserves, without adverse effects on health among high-risk beef calves.

The objective of this study was to evaluate the changes in enzymic activity, metabolites, and hematological responses during the first 56-d of arrival of newly received calves, which were qualified at reception as high-risk but diagnosed as clinically healthy. A total of 320 blood samples were taken from 64 crossbred bull calves (average initial body weight = 148.3 ± 1.3 kg) at different times from arrival (d 0, 14, 28, 42, and 56 of received). Calves included in the study were received in June (n = 20), November (n = 24), and April (n = 20); thus, experimental treatments were arranged in a generalized complete block design (three blocks = month of arrival). The following parameters were determined: total white blood cells (WBC): lymphocytes (LYM), lymphocytes % (LYM%), monocytes (MON), monocytes % (MON%), granulocytes (GRA), granulocytes % (GRA%), platelets (PLT), and mean platelet volume (MPV); red blood cells (RBC): red blood cell distribution width test % (RDW%), hematocrit (HCT), and mean corpuscular volume (MCV); hemoglobin (HGB): mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). The enzymatic activity and metabolites analyzed were alkaline phosphatase (ALP), gamma glutamyltransferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total protein (TP), albumin (ALB), globulin (GLO), ALB/GLO ratio, blood urea nitrogen (BUN), creatinine (CRE), total bilirubin (TBIL), total cholesterol (TCHO), triglycerides (TG); (4) calcium (Ca), glucose (GLU), sodium (Na⁺), potassium (K⁺), and chlorine (Cl⁻). It was observed that ALP, ALT, TP, ALB, GLO, ALB/GLO ratio, TCHO, TG, Ca, and GLU increased as days from reception increased (linear effect, p ≤ 0.04), whereas CRE and TBIL were reduced (linear effect, p ≤ 0.02). A quadratic response (p ≤ 0.001) was observed to GGT and AST values being maximal on days 1 and 56 after arrival (p ≤ 0.001). Na⁺, K⁺, and Cl⁻ concentrations were not affected by prolonged days after arrival. Finally, blood cells of LYM, LYM%, PLT, RBC, HGB, HCT%, MCV, and MCH increased (linear effect, p ≤ 0.001) as the number of days after arrival increased. Whereas MON% was linearly decreased (p ≤ 0.05). It was concluded that even when all parameters were within the range of reference intervals (RIs) determined for healthy cattle, during the period of monitoring, as the days after arrival lengthened, blood serum parameters related to health and immunity increased, and metabolites related to tissue injury decreased. In contrast, plasmatic electrolytes (Na⁺, K⁺, and Cl⁻) were slightly reduced as the day after arrival increased. Apparently, at least 42 d is the minimum period after arrival to permit calves to reach more adequate physiological and metabolic conditions before starting the fattening phase.

Limited empirical evidence is available validating the energy value assigned to steam-flaked corn (SFC) for small ruminants in current NRC feeding standards. Therefore, the objective of this study was to evaluate the effects of corn processing, including steam-flaking, on growth performance, dietary energetics, visceral fat deposition, and carcass characteristics of finishing lambs. Forty-eight Dorper × Katahdin ram lambs (42.0 ± 0.27 kg initial body weight) were assigned to one of four treatments (n = 12 per treatment) and fed high-concentrate diets for 45 d containing 50% yellow corn grain. Treatments differed only in the form of corn presentation: whole corn (WC), cracked corn (CC), ground corn (GC), or SFC. Cracked corn was produced using a roller mill without a sieve (mean particle size 4 to 6 mm), whereas ground corn was processed through a 3 mm sieve (mean particle size 1 to 2 mm). For SFC, WC was steamed for 20 min at approximately 102 °C before rolling, and flake density was adjusted to 0.36 kg/L by roller tension. Dry matter intake was 10.1% greater in SFC than in WC (p = 0.020), whereas CC and GC showed intermediate responses. Final body weight (+4.7%), average daily gain (+30.8%), and observed dietary net energy for maintenance (NE_m; +10.4%) were greater in SFC than in GC (p < 0.05), whereas WC and CC showed intermediate responses. Gain-to-feed ratio was greater in SFC than in GC and CC (p = 0.028), representing increases of 24.6% and 18.2%, respectively. Empty body weight and visceral fat deposition were also affected by treatment (p < 0.05), with greater visceral fat deposition in SFC and CC than in GC, whereas WC showed intermediate responses. Steam-flaked corn increased longissimus lumborum muscle area by 17.7% relative to GC (p = 0.048) and increased perirenal fat deposition relative to WC, CC, and GC (p = 0.048). However, most carcass characteristics and meat quality variables were not affected during the 45 d experimental period (p > 0.05). Using a replacement technique, estimated NE_m values (Mcal/kg) for CC, GC, and SFC were 2.00, 1.88, and 2.24, respectively. The NE_m value for SFC was in close agreement (2.24 vs. 2.30 Mcal/kg) with current feeding standards, whereas dry-processed corn showed lower estimated NE_m values (p = 0.025), representing reductions of 9% and 17% for CC and GC, respectively. In conclusion, SFC improved growth performance and dietary energy utilization relative to GC, while producing limited effects on carcass-related responses under the conditions of this 45 d study.

Thirty-six Dorper × Katahdin intact male lambs [44.0 ± 0.27 kg initial body weight (BW)] were used in a randomized complete block design to evaluate the effects of supplementing different organic chromium (OrCr) sources on growth performance, dietary energetics, carcass traits, meat quality, and economic return. Treatments (n = 9 lambs/treatment) were (1) Control (no Cr), (2) chromium-enriched yeast (Cr-Yeast), (3) chromium–methionine (Cr-Met), and (4) chromium–propionate (Cr-Pr). All Cr sources were provided at 1.2 mg elemental Cr/lamb/d for 45 d. Lambs received a high-energy finishing diet (78:22 concentrate/forage; steam-rolled corn-based). Dry matter intake was not affected (p = 0.583; 1.27 ± 0.034 kg/d). Compared with Control, Cr-Pr increased final BW (+5%; p = 0.025) and average daily gain (+66%; p = 0.034), and improved feed efficiency (+59%; p = 0.045) and observed-to-expected net energy ratio (+22%; p = 0.042); Cr-Met and Cr-Yeast showed intermediate responses. No differences were observed (p > 0.05) in longissimus lumborum muscle area, cold carcass weight, dressing percentage, cooling loss, or zoometric traits. Rib and rump fat thickness decreased with Cr-Met (−15 and −12%; p = 0.024 and p = 0.048) and with Cr-Pr (−19 and −13%; p = 0.024 and p = 0.048), and all OrCr sources reduced omental (−6 to −25%; p = 0.034), mesenteric (≈−7%; p = 0.042), visceral (−12 to −16%; p = 0.034), and perirenal fat (−25 to −39%; p = 0.028). Empty body weight and hot carcass weight increased with Cr-Pr (p = 0.029 and p = 0.031, respectively). Cr-Yeast and Cr-Pr increased muscle proportion (+5 to +7%; p = 0.003) and reduced carcass fat (−20 to −27%; p = 0.018), improving the muscle/fat ratio (+42 to +50%; p = 0.045). Cr-Pr improved water-holding capacity (+27%; p = 0.014) without affecting pH_24h, purge loss, cooking loss, or Warner–Bratzler shear force (p > 0.05). Cr-Pr reduced cost per kg of gain (−31%; p < 0.001) and increased income (+188% live; +105% carcass; p < 0.001), whereas Cr-Met and Cr-Yeast provided moderate benefits. In conclusion, OrCr supplementation improved dietary energy utilization, growth, carcass traits, and meat quality, enhancing profitability in lambs finished at heavier weights, with Cr-Pr producing the greatest responses.

This study determined the level at which corn stover (CS) could be progressively replaced with condensed tannin-containing woody biomass (CTWB) from Quercus rugosa without compromising dietary acceptance, growth, energy utilization, or reproductive development in prospective breeding ram lambs. In Experiment 1, eight intact Rambouillet ram lambs (5 months old; 40.7 ± 0.2 kg initial body weight) were simultaneously offered diets containing 0–80% CTWB (CTWB-0–CTWB-80), equivalent to 0.00–20.96 g condensed tannins (CT)/kg dry matter (DM), in an 8-d preference trial. In Experiment 2, 36 intact Rambouillet ram lambs (6 months old; 49.97 ± 0.79 kg initial body weight) were assigned for 70 d to diets containing 0–60% CTWB and a calculated CT contribution from CTWB of 0.00–15.72 g/kg DM (n = 9/treatment). In the preference trial, CTWB-20 reduced CS from 80 to 60% without affecting the proportion of diet consumed or relative palatability index compared with CTWB-0, whereas inclusions ≥40% reduced both responses (p = 0.0143 and p = 0.0146, respectively). In the growth trial, CTWB-20, corresponding to 5.24 g CT/kg DM from CTWB, maintained growth performance comparable with CTWB-0 and produced a greater overall growth response than CTWB-60, reflected by greater final body weight (63.95 vs. 57.87 kg; p = 0.016), average daily gain (0.202 vs. 0.126 kg/d), cumulative body weight change (14.19 vs. 8.93 kg; p = 0.019), and gain-to-feed ratio (0.094 vs. 0.058; p = 0.011). Dry matter intake (DMI) remained similar (p = 0.278). As CTWB increased, expected DMI increased (p < 0.0001), the observed-to-expected DMI ratio decreased (p = 0.003), and the observed-to-expected net energy for maintenance (NE_m) and gain (NE_g) ratios increased (p ≤ 0.045), although observed NE_m and NE_g concentrations remained unchanged (p = 0.146). Rib fat thickness was maintained with CTWB-20 but decreased with CTWB-40 and CTWB-60 (p = 0.004), whereas longissimus muscle area, scrotal circumference, and sperm motility remained similar (p ≥ 0.157). Additionally, CTWB-20 was associated with greater sperm viability (p = 0.032), while all CTWB levels were associated with fewer morphologically abnormal sperm (p = 0.005). Finally, treatment did not affect income over feed cost or cost of gain (p = 0.217 and p = 0.735, respectively), indicating that partial replacement with CTWB did not adversely affect economic efficiency. Overall, 20% CTWB reduced CS from 60 to 40% and provided a favorable balance among dietary acceptance, growth, semen characteristics, and economic efficiency.