Greater Average Daily Gain Research Articles

Effect of sex and milk replacer with or without supplemental carnitine and arginine on growth characteristics, carcass, and meat quality of artificially reared low-birth weight pigs.

This study compared milk replacer either remaining unsupplemented (CON) or supplemented with 0.5g L-carnitine plus 16.7g L-arginine/kg (CarArg) and fed to 48 low-birth weight (L-BtW) artificially reared piglets (24 per group) from days 7 to 28 of age. Eight farrowing series were needed to complete the study. On day 28, the lightest piglets were slaughtered, and the heaviest pigs were weaned. The heaviest pigs were weaned on day 28 and offered free access to a starter (weaning to 25kg body weight [BW]), grower (25 to 60kg BW), and finisher diet (60 to 96kg BW on day 170 of age). After euthanization on days 28 and 170, blood was sampled for assessment of serum metabolite and hormone concentrations, and the semitendinosus muscle (STM) was weighed, and later subjected to enzyme activity analysis and assessment of myofiber characteristics. In the 170-d-old pigs carcass and meat quality traits were assessed. Growth data were analyzed accordingtoatwo-way analysis of variance (ANOVA), with dietary treatment and farrowing series as fixed effects, while remaining data were analyzed with dietary treatment, sex, their interaction, and farrowing series as main factors. Dietary treatments affected (P ≤ 0.049) muscle enzyme activity at both day 28, with greater citrate synthase (CS) and LDH activities and lower HAD:CS ratio in STM light portion, and lower LDH:CS ratio in STM dark portion, and 170 of age with lower HAD:CS ratio. In the starter period, CarArg pigs had greater average daily gain (P = 0.021) and average daily feed intake (P = 0.010). At slaughter, these pigs had lower (P = 0.013) glucose and greater (P = 0.022) urea serum concentrations. However, supplementing the milk replacer with carnitine and arginine had no long-term effects on growth performance, carcass composition, and meat quality of L-BtW pigs. In addition, muscle morphology and myofiber-related properties remained unaffected by the supplementation.

99 Phytochemicals as medical growth promoter replacement on growth performance in wean to finisher pigs

Abstract Stress can disturb the ecological balance of the microbiota residing in the GI tract of piglets leading to dysbiosis. This unhealthy imbalance causes the piglets to be more vulnerable to deleterious effects induced by opportunistic pathogens. Antibiotics and increased zinc levels have often been used as dietary supplements to help minimize these stressors in pigs. Emerged evidence suggests that phytochemicals can promote growth by boosting nutrient digestibility, immune cell activity, and possessing bactericidal characteristics. We evaluated two phytochemicals formulations as safer and more environmentally friendly dietary alternatives for postweaning pigs. We used a total of 240 weaned piglets [average body weight (BW): 6.26 ± 0.36 kg] which were blocked (n = 8) by BW and then randomly assigned to 1 of 5 dietary treatments. Treatments were negative control (NC), Mecadox 10 (Phibro Animal Health Corp., Teaneck, NJ) + ZnO positive control (PC), Mecadox + phytochemical 1 (Lippia origanoides; Phyt1+AB), phytochemical 1 alone (Phyt1), and phytochemical 2 (Lippia origanoides + Rosmarinus officinalis + Sodium humates; Phyt2). The pigs were fed a 7-phase feeding regime: Nursery phase (NP) 1, 2, and 3, Grower phase 1 and 2 (Grower), and Finisher phase 1 and 2 (Finisher). The antibiotic and ZnO were withdrawn at the end of NP3, while Phyt1 and Phyt2 remained in feed throughout the entire study period. Data were analyzed using Mixed procedure of SAS (Cary, NC) with treatments as the main effect and BW blocks as the random effect. Pen was the experimental unit. Supplemental phytochemicals (Phyt1+AB, Phyt1, Phyt2) had greater average daily gain (ADG) and gain to feed ratio (G:F) during NP1 when compared with the pigs fed NC, but were still less than pigs fed PC (P < 0.0001). Pigs fed PC maintained a greater ADG during nursery overall than NC, Phyt1, and Phyt2 with pigs fed Phyt1+AB as intermediate (P < 0.0001). Phyt1 exerted an adverse effect (Phyt1+AB and Phyt1) on ADG during relatively mild stress in Grower phase (Grower, P = 0.0146), and resulted in the lighter BW at the end of Grower than pigs fed PC (P = 0.031). Notably, the pigs experienced summer heat stress during the Finisher phase, of which, the presence of phytochemicals minimized. Pigs fed Phyt2 had a greater ADG during Finisher than pigs fed NC with pigs fed PC, Phyt1+AB, and Phyt1 as intermediates (Finisher, P = 0.0419), while pigs fed Phyt1+AB and Phyt2 had greater G:F when compared with pigs fed PC and NC with pigs fed Phyt1 as intermediate (Finisher, P = 0.0032). Collectively, we demonstrated that phytochemical 2 can be a safer medication diet replacement to help pigs sustain weaning and heat stress. The mode of action and the optimum concentrations of these phytochemicals to achieve maximum benefits need further investigation.

58 Evaluation of a phytogenic blend on growth performance, health, carcass traits, and efficiency of dietary net energy utilization in finishing beef steers

Abstract The objective of this study was to determine if a formulated blend of capsicum oleoresin, clove essential oil, and garlic essential oil (CCG; Fytera Advance - Selko USA, Indianapolis IN) influences measures of cattle growth, efficiency, health, or carcass traits, during the finishing phase in steers fed a concentrate-based diet. Charolais × Angus steers [n = 96; initial shrunk body weight (BW) = 391 ± 34.0 kg] were used in a 144-d finishing experiment at the Ruminant Nutrition Center in Brookings, SD. Steers were individually weighed and allotted to one of 14 pens (n = 6 to 7 steers; 7 pens/treatment) in a randomized complete block design and randomly assigned to 1 of 2 treatments: control diet without the test product (CON) or a diet including CCG at 500 mg/steer daily (CCG). The average nutrient content of the finishing diet was: 13.5% CP; 18.7% NDF; 2.06 Mcal/kg NEm; and 1.39 Mcal/kg NEg; monensin sodium was included in the diet at 30 g/907 kg. Steers were fed twice daily, and bunks were managed according to a slick bunk system. There were no differences (P ≥ 0.10) in any growth performance outcome from d 1 to 35, 36 to 70, or 71 to 98. The within pen standard deviation for average daily gain (ADG) from d 71 to 98 tended to be reduced (P = 0.10) for CCG steers compared with CON. From d 99 to 144 steers supplemented CCG had 5% greater dietary energy utilization (P = 0.01), tended to have 5% greater ADG (P = 0.09), and 8% improved feed efficiency (P = 0.01). Experimental periods when improved pen gain uniformity and feed efficiency were observed coincided with increased summertime temperatures. No differences (P ≥ 0.15) were noted for cumulative growth performance. No differences were noted for any carcass measurements or categorical carcass outcomes, nor lung or liver health outcomes (P ≥ 0.15). Use of CCG had no appreciable influence on any cumulative growth performance responses. However, the use of CCG decreased within pen variation in ADG indicating more uniform nutrient intake among cattle and increased feed efficiency during summertime heat events.

95 Effects of increasing standardized ileal digestible valine:lysine ratio on growth performance in finishing pigs

Abstract Two experiments evaluated the effects of increasing standardized ileal digestible (SID) Val:Lys ratio on the growth performance of 38 to 67 kg (Exp. 1) and 90 to 116 kg (Exp. 2) finishing pigs. In Exp. 1, pigs (n = 647; DNA 600 × 241) were randomly allotted to 1 of 6 dietary treatments with 8 or 9 pigs per pen and 12 replications per treatment. Diets were corn-soybean meal-based, and low and high Val diets were manufactured and blended to create intermediate Val:Lys ratio diets. Diets were formulated to contain 0.90% SID Lys, and treatments consisted of SID Val:Lys ratios of 60%, 63%, 66%, 69%, 72%, and 75%. At the conclusion of the 27-d study, all pigs were fed a common diet for 30 d and then randomly re-allotted to 1 of 6 diets formulated to contain 0.65% SID Lys and SID Val:Lys ratios of 63%, 66%, 69%, 72%, 75%, and 78% (Exp. 2). In both experiments blood samples were collected from 3 pigs per pen on d 15 for plasma urea nitrogen (PUN) analysis. In Exp. 1, final body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI) increased (quadratic, P < 0.05) as Val:Lys increased (Table). Pigs fed the diet with 66% SID Val:Lys ratio had the greatest ADG, whereas pigs fed 72% SID Val:Lys ratio had the greatest ADFI. As the Val:Lys ratio increased, gain to feed ratio (G:F) decreased (linear, P < 0.05). Valine and Lys intake increased (quadratic, P < 0.05) as the Val:Lys ratio increased with the greatest intake observed at 72% SID Val:Lys. Valine and Lys intake per kg of gain increased (linear, P < 0.05) as the level of Val in the diet increased. Plasma urea nitrogen decreased (linear, P < 0.05) as the Val:Lys ratio increased. In Exp. 2, ADG and ADFI increased (linear, P < 0.05) as Val:Lys increased. However, for ADG there was little improvement from feeding greater than 69% SID Val:Lys. There were no linear or quadratic effects (P > 0.05) for SID Val:Lys on G:F or PUN. Valine intake, Lys intake, and Val intake per kg of gain increased (linear, P < 0.05) as the Val:Lys ratio increased. There were no differences (P > 0.05) observed in Lys intake per kg of gain. Based on the results of this study, it appears that 66% SID Val:Lys ratio maximizes ADG in 38to 67 kg pigs, and only small increases in ADG were observed when feeding greater than 69% SID Val:Lys for 90 to 116 kg finishing pigs.

PSIII-21 Impact of high zinc oxide supplementation or lignocellulose supplement on chronic markers of intestinal inflammation and growth of weaned piglets

Abstract The objective of this project was to study the effects of high zinc oxide (ZO) supplementation and fiber supplement from lignocellulose (LIGCEL) on chronic markers of intestinal inflammation and growth of weaned piglets. At weaning (21 d), 150 piglets (body weight = 6.39 ± 0.276 kg) were transferred from a farrowing farm to a nursery farm where they were divided into 30 pens of 5 piglets per pen according to their weanling weight. Each pen was assigned to one of the following three treatments: Control (CON, 150 mg/kg of zinc), ZO (2,500 mg/kg of zinc), and LIGCEL (CON+3% lignocellulose). The ZO and LIGCEL supplements were added to a phase 1 diet. The experimental diets (phase 1) were distributed for 14 d. Subsequently, all piglets received the same diets from phases 2 and 3 for two periods of 14 d. During the experiment, piglets were weighed upon arrival and after phases 1, 2, and 3. The feed was distributed every day and the total quantities calculated for each of the feeding phases. The average daily gain (ADG), average daily feed intake (ADFI) and feed conversion (FC) were subsequently calculated (Table 1). On d 6 and 13, the blood of two piglets per pen was collected to determine the content of D-lactate and diamine oxidase (DAO). Fecal samples from these two piglets were also taken to evaluate the calprotectin and neopterin contents. During phase 1, ADG was greater for ZO piglets compared with the CON animals with an intermediate value for the LIGCEL group (P < 0.001). The ADFI was greater for the ZO compared with the CON and LIGCEL treatments (P < 0.003). Piglets in the ZO and LIGNOCELL treatments had less FC than those in the CON group (P < 0.001). During phase 2, only the FC was greater for the ZO and LIGCEL treatments compared with CON animals (P < 0.013). During phase 3, growth performances were not affected by the dietary treatments. For the entire experiment, ZO piglets had greater ADG than those in the CON group with an intermediate value for LIGCEL treatment (P < 0.019). D-lactate decreased from d 6 to 13 while DAO increased (P < 0.001). The DAO was also greater for ZO and LIGCELL piglets compared with CON animals (P < 0.001). Neopterin was greater for ZO treatment but only on d 13 (Trt × day, P < 0.010). Finally, calprotectin decreased from d 6 to 13 (P < 0.001) but was not affected by dietary treatments. In conclusion, ZO and LIGCEL fiber act positively on growth by modulating markers of intestinal inflammation. LIGCEL fiber could, therefore, be an alternative to ZO in the diet of weaned piglets.

233 Inclusion of a multispecies fungal feed additive in forage-based diets fed to beef cattle: Effects on growth performance and ruminal fermentation

Abstract The objective was to evaluate the effect of adding a multispecies fungal feed additive (MFA; Aspergillus flavus, Aspergillus niger, Aspergillus oryzae) to forage-based diets fed to beef cattle on growth performance and ruminal fermentation. Experiment 1 evaluated the effect of supplementing Angus × SimAngus-crossbred steers [n = 80; initial body weight (BW) = 370 ± 44 kg] with varying doses of an MFA in a randomized complete block design. Steers were blocked by BW and housed in 8 feedlot pens (randomly assigned 2 pens per treatment) where a hay-based diet was fed for 122 d. The hay-based diet was offered with the inclusion of the MFA at 0.02, 0.04, and 0.08 % of the diet dry matter (DM), or without the inclusion of the MFA (CON). Steers were weighed at 28-d intervals. For experiment 2, ruminally cannulated Angus × SimAngus cows (n = 4; initial BW = 569 ± 21 kg) were used in a crossover design with two 21-d study periods to evaluate the effect of dietary inclusion of an MFA on in situ digestion and rumen metabolites. Treatments consisted of a forage-based diet with (WFA) or without (CON) the inclusion of the MFA. In situ digestion was evaluated on d 5, 10, and 20 throughout each period. In-situ bags were incubated in the rumen for 0 to 36 h, sampling every 4 h. On d 20, samples of ruminal fluid were collected to analyze short-chain fatty acids (SCFA) concentration. All data were analyzed using the PROC MIXED procedure of SAS. For experiment 1, a polynomial contrast was used. For experiment 2, the interaction between period and treatment was not significant (P > 0.45). In Experiment 1, the final BW, average daily gain (ADG), and gain to feed ratio (G:F) changed cubically (P ≤ 0.04; Table 1) as dietary inclusion of the MFA increased. Steers supplemented with the MFA at a rate of 0.02% of the diet DM were heavier at the end of the 122-d study period and had the greatest ADG and G:F among treatments. No differences between treatments (P ≥ 0.37) were observed for dry matter intake. In Experiment 2, no treatment × time interactions and treatment effects were detected (P ≥ 0.17; Table 2) for the in-situ disappearance rate and degradation kinetics of the diet DM, neutral detergent fiber, and acid detergent fiber. In addition, MFA supplementation did not affect (P ≥ 0.13; Table 3) the SCFA profile and the total SCFA content in the rumen fluid. Results from these studies indicate that dietary inclusion of an MFA might be an effective alternative to increase the feed efficiency of beef cattle-fed forage-based diets. However, the precise mode of action warrants further investigations.

156 Growth performance, energy, and nutrient digestibility of nursery pigs fed high-shear dry extruded corn and soymeal

Abstract Altering the processing method via high-shear dry extrusion of both soybean meal and corn has been shown to improve diet energy and digestibility. The objective was to evaluate the effect using high-shear dry extruded corn and mechanically processed soymeal on growth performance, energy, and nutrient digestibility of nursery pigs. A total of 240 newly weaned pigs [initial body weight (BW) = 5.7 ± 1.3 kg] were assigned to 1 of 5 dietary treatments (n = 16 pens per treatment with 3 pigs per pen) in a complete randomized design for three dietary phases over a 6 wk study duration. Pigs were allowed a 7-d acclimation period where they were fed a common commercial medicated starter pellet diet (d 0-7, Phase 1). In phase 2 and 3, experimental diets included: 1) solvent-extracted soybean meal and conventional ground corn (Con), 2) solvent-extracted soybean meal and high-shear dry extruded corn (ECorn), 3) mechanically processed soymeal and conventional corn (ExSoy), 4) mechanically processed soymeal and high-shear dry extruded corn (same ME and Lysine as treatment 1 to 3; Comb), and 5) mechanically processed soymeal and conventional corn (energy floated with same Lys:ME; Comb+). The phase 2 mash test diets contained 0.40% titanium dioxide as a digestibility marker (d 8-21) and phase 3 test diets were fed from d 22-42. Pigs were individually weighed on d 0, 7, 21 and 42 and feed disappearance was recorded to calculate average daily feed intake (ADFI) and Gain:Feed within phase 1, 2 and 3, and overall (phase 2 and 3 combined). Data were analyzed using pen as the experimental unit. Compared with Cont, end BW did not differ in the ECorn and ExSoy treatment, while Comb and Comb+ pigs were 13 to 17% lighter (26.1, 24.2, 24.0, 22.6 and 21.5 kg, respectively, P = 0.004). Overall, the Con fed pigs had 30% greater average daily gain (ADG) and 12 to 21% increase in feed efficiency compared with either Comb or Comb+ treatments (P < 0.001). Overall ADFI did not differ. During phase 3, Con and ECorn fed pigs observed increased ADG and feed efficiency compared with pigs fed either Comb treatment (Both P = 0.002, respectively). Compared with Cont, ECorn and Comb+ had greater GE ATTD coefficients, while ExSoy and Comb were less (82.1, 84.6, 86.9, 78.7 and 79.1%, respectively, P < 0.001). Nitrogen ATTD coefficients were greatest in Comb+, followed by ECorn, Cont, ExSoy and Comb (84.4, 78.8, 77.9, 73.0 and 72.3%, respectively, P < 0.001). In conclusion, substituting conventional corn or solvent-extracted soybean meal with extruded corn or mechanically processed soymeal resulted in equal pig growth performance. Further research is needed to determine the effects on the performance of nursery pigs fed diets including more than one high-shear dry extruded ingredients.

191 Supplementing short- and medium-chain fatty acid-based products increases the health and performance of weaned piglets

Abstract Several feed supplements have received interest for their potential to increase growth performance and health post weaning, including alternatives to high levels of zinc oxide (ZnO) such as short- and medium-chain fatty acids (SCFA, MCFA), and phytogenics. The objective of this study is to observe the growth performance and intestinal health effects from the supplementation of SCFA with and without the addition of MCFA and phytogenics. The trial was performed on a commercial farm in Segovia, Spain. Piglets (n = 192; Topigs sow x Pietrain) were weaned at 28 d. The initial body weight (BW) was 8.5 ± 1.5 kg. Two phases were fed; phase 1 (d 1-14) and phase 2 (d 15-35). Piglets were distributed evenly to 4 treatments of 8 pens, 6 pigs/pen. Four treatments were evaluated: a negative control (NC) without addition of dietary additives any other growth promoters, a positive control (PC) with 3,000 ppm ZnO in the prestarter diet, NC with 2,000 ppm SCFA, coated butyrate, in the prestarter and 1,500 ppm SCFA in the starter (SB), and NC with a mixture of SCFA, MCFA, and phytogenics supplemented at 3,000 ppm in the prestarter and 2,000 ppm in the starter (SMP). Feed intake and individual BW were measured weekly. On d 0 and 7, one piglet per pen was rectally sampled for qPCR analysis of Escherichia coli, Streptococcus suis, and Clostridium perfringens. Veterinary interventions were recorded. Statistical analysis of growth performance, E. coli, and S. suis counts data were analyzed by ANOVA and Tukey’s t-test. The number of veterinary interventions and the occurrence of a high C. perfringens load were analyzed with a chi-square test. All statistical significance was set at P ≤ 0.05. The PC had the greatest average daily gain (ADG) at d 14 with 235 g/d while the NC and the SB had statistically less ADG with 217 and 212 g/d, NC and SB, respectively (P ≤ 0.05); however, no statistical differences between treatments were present at the end of the trial (332 NC, 335 PC, 331 SB, 347 SMP, P > 0.05). The feed conversion ratio (FCR) was less for PC (1.22) and SMP (1.23) in phase 1 than NC (1.33) and SB (1.35; P ≤ 0.05). No differences were detected in phase 2 (1.36 NC, 1.31 PC, 1.36 SB, 1.27 SMP; P >0.05). Dietary interventions did not significantly affect E. coli and S. suis counts. However, SB and SMP treatments had sufficiently reduced fecal C. perfringens load and antimicrobic treatments, P ≤ 0.05 (Table 1). In conclusion, supplementation of SCFA, with or without MCFA or phytogenics, reduced C. perfringens and incidence of diarrhea. The addition of MCFA and phytogenics with SCFA, improved performance to the positive control.

Effect of dawri-damaa (Pentas schimperiana) leaf meal supplementation on performances, carcass characteristics, and economic feasibility of sheep fed native grass hay.

With a growing export and local market, sheep farming is critical to the economy of smallholder farmers; however, indigenous sheep breeds usually exhibit low carcass output and live weight due to nutritional constraints. The study aimed to investigate the impact of supplementing local sheep with dawri-damaa leaf meal (DDLM) on their performance, carcass characteristics, and profitability when fed native grass hay. The research used a randomized complete block design (RCBD) to administer four feeding treatments (T1, T2, T3, and T4 at 0%, 30%, 50%, and 70% DDLM, respectively) to 20 local uncastrated male lambs having an average 23.72 ± 0.73 kg body weight and average age of 11.72 ± 0.74 months. Greater doses of DDLM in the diet resulted in greater average daily gain (ADG) of 51.4-83.8 g/day and feed conversion efficiency (FCE) of 0.066-0.089 in lambs, compared to 15.0 g/day ADG and 0.025 FCE in lambs under control diet (T1). Additionally, the lambs had increased slaughter body weight (SBW), empty body weight (EBW), and hot carcass weight (HCW) in T4 and T3 compared to other treatments (p < .05). There were no significant differences in dressing percentages (DPs) across any treatment group. The study also discussed the economic viability of supplementing with DDLM, suggesting that feeding 70% daily dry matter of DDLM at 2.5% live weight might be beneficial depending on availability, access, and cost factors. In conclusion, feeding DDLM up to 70% has improved the performance of sheep and is economically feasible. Further research might be required to discover whether such levels of inclusion are harmful and apply different processing methods for feeding animals.

Performance and economics of fall grazing cover crops compared to a traditional drylot system of fall-calving cow-calf pairs

The objective of this study was to evaluate cow and calf performance while strip grazing a cover crop mix consisting of radishes, turnips, oats, and common vetch (CC) compared to a traditional, drylot management system (CON) of the Iowa State University Beef Teaching Farm fall-calving herd. The study was repeated for 3 consecutive years to account for weather variation.&amp;nbsp; Each growing season presented a unique situation. With a targeted seeding date of August 1st each year, yields ranged from 2,750 &amp;ndash; 4,830 lbs of dry matter per acre, averaging 3,952 lbs. The greatest yield was observed in 2019 while the lowest yield occurred in 2020 with drought conditions restricting growth. Growth in 2021 was intermediate, but peak yield occurred after grazing began due to a delayed killing frost. Turnout dates ranged from early-November to mid-December, and fall pairs grazed for an average of 32 days, ranging from 17 &amp;ndash; 45 days.&amp;nbsp; Despite fluctuation in cow body weights between treatments over the years, calves on CC had equal to or greater average daily gain and final body weights compared to calves on CON. Over the 3 years, CC calves gained an average of 0.36 lbs more per head per day than their CON counterparts. This advantage may be a reflection of CC dams producing a higher quality milk due to the high-quality forage diet and the ability of calves to graze alongside their dam.&amp;nbsp; An economic analysis of the 3-year project revealed a 29% average reduction in calf cost of gain of cow-calf pairs grazing cover crops ($1.11/lbs of gain) compared to cow-calf pairs fed in a drylot setting ($1.57/lb of gain). Compared to the standardized drylot in this scenario, this efficiency boost emphasizes the value of extending the grazing season, especially in times of high feed costs.

Herbage responses and animal performance of nitrogen-fertilized grass and grass-legume grazing systems

AbstractThe study evaluated forage and livestock performance in different grazing systems over two years. Treatments were three contrasting grazing systems: (I) N-fertilized bahiagrass (Paspalum notatum Flüggé) in the summer overseeded during the winter by N-fertilized ryegrass (Lolium multiflorum) and oat (Avena sativa L.) (Grass + N); (II) unfertilized bahiagrass during the summer overseeded with ryegrass + oat and a blend of clovers (Trifolium spp.) in the winter (Grass + Clover); (III) unfertilized bahiagrass and rhizoma peanut (RP; Arachis glabrata Benth.) mixture during summer, overseeded during winter by ryegrass + oat + clovers mixture (Grass + Clover + RP). Average daily gain (ADG), gain per area (GPA), and stocking rate (SR) in the winter did not differ across treatments and averaged 0.87 kg/d (P = 0.940), 303 kg/ha, and 2.72 AU/ha. In the summer, Grass + Clover + RP had greater ADG than Grass + N (0.34 vs. 0.17 kg/d, respectively). During the summer, the GPA of Grass + Clover + RP was superior to Grass + N (257 vs. 129 kg/ha, respectively), with no difference in SR among treatments at 3.19 AU/ha. Over the entire year, ADG and GPA tended to be greater for Grass + Clover + RP. Annual SR differed between treatments, where Grass + N was greater (3.37 AU/ha) than the other treatments, which averaged 2.76 AU/ha. Integration of legumes into pasture systems in the summer and winter contributes to developing a sustainable grazing system, reducing N fertilizer use by 85% while tending to increase livestock productivity even though SR was decreased by 18%.

Effects of α-amylase and coated α-amylase supplementation on growth performance, nutrient digestion, and rumen fermentation in Holstein bulls.

This study evaluated the impacts of α-amylase (AM) and coated α-amylase (CAM) on bull performance, nutrient digestibility, and ruminal fermentation. This study randomized 60 Holstein bulls of 365 ± 11.5 days of age and 457.5 ± 9.35 kg body weight into three groups: without AM addition, adding AM 0.6 g/kg dry matter (DM), and adding CAM 0.6 g AM/kg DM, separately. This whole experimental period was 80 days, including a 20-day adaptation period and a 60-day data and sample acquisition period. In comparison with the unsupplemented control, dry matter intake (DMI) was unaltered; however, average daily gain (ADG) and feed efficiency (FE) were greater for AM or CAM addition. Bulls receiving AM or CAM supply had greater total-tract nutrient digestibility, ruminal total volatile fatty acids (VFA) content, propionate molar proportion, cellulolytic enzyme and AM activities, and the number of microorganisms. In addition, the activities of AM and trypsin in the jejunum and ileum and glucose, albumin, and total protein concentrations in serum were greater for AM or CAM addition compared to the control. When comparing the supplementation mode of AM, bulls receiving CAM addition had greater ADG and FE. The crude protein and starch digestibility and intestinal AM and trypsin activity were higher, while acid detergent fiber (ADF) digestibility was lower for CAM addition than for AM addition. The lower propionate molar proportion and cellobiase and carboxymethyl cellulase activities, together with Ruminococcus albus, Ruminococcus flavefaciens, and Fibrobacter succinogenes populations were observed for CAM addition compared with AM addition. However, there were greater glucose, albumin, and total protein concentrations in serum after adding CAM. According to the data, the supply of AM improved ADG, nutrient digestion, and rumen fermentation. Notably, the optimum supplementation mode was in the form of CAM in bulls.

Exploring the impacts of fescue toxicosis on the pulmonary arterial pressure of angus cows.

Vasoconstriction of peripheral blood vessels is one of the hallmark symptoms of fescue toxicosis in cattle. Thus, it was hypothesized that exposure to ergot alkaloids would increase the pulmonary arterial pressure (PAP). The objectives of this study were to examine the relationship between PAP and different physiological parameters of cows grazing either endophyte-infected (EI) or novel-endophyte (EN) fescue, then evaluate changes in PAP and other physiological measurements in cows exposed to EI pastures and deemed as susceptible or tolerant based on animal performance. Pregnant Angus cows at 2 different locations grazed either EI or EN fescue pastures for 14 consecutive weeks starting in early April of 2022. Forage measurements were collected to assess ergot alkaloid exposure throughout the study. In addition to measuring PAP, weekly measurements and blood samples were collected to evaluate physiological responses to ergot alkaloid consumption. The Fescue Toxicosis Selection Method (FTSM) was used for a post hoc analysis to identify cattle as either tolerant (EI-TOL) or susceptible (EI-SUS) when challenged with ergot alkaloid exposure. Data were analyzed using a MIXED procedure of SAS with repeated measures. Cows grazing on EN pastures had greater mean PAP values than EI cows, (P < 0.01), whereas a location effect was identified when comparing both EI-TOL and EI-SUS groups (P < 0.01). Cows exposed to EN pastures had greater average daily gain (ADG) (P = 0.04) and progesterone (P4) concentrations (P < 0.01), and lower hair shedding scores (HSS; P < 0.01) than EI cows. The EI-TOL cows tended to have greater final body weight, ADG and had lower HSS (P < 0.01) than EI-SUS cows. While cattle consuming EI tall fescue exhibited classical physiological changes, the decrease in PAP of cattle consuming EI fescue was unexpected and contradicted the initial hypothesis. Furthermore, the FTSM provides a means to identify animals with superior performance in spite of the chronic exposure to ergot alkaloids. Continued investigations examining the interaction between ergot alkaloid exposure and cardiovascular parameters will lead to a fuller understanding of the disease and are pivotal for developing innovative strategies that enhance best management practices to help guarantee the sustainability of the U.S. beef industry.

Trace mineral source and chromium propionate supplementation affect performance and carcass characteristics in feedlot steers.

Angus-crossbred steers (n = 400; 369.7 ± 7.6kg) were used to determine the influence of trace mineral (TM) source and chromium propionate (Cr Prop) supplementation on performance, carcass characteristics, and ruminal and plasma variables in finishing steers. Steers were blocked by body weight (BW) and randomly assigned within block to treatments in a 2 × 2 factorial arrangement, with factors being: 1) TM source (STM or HTM) and 2) Cr supplementation (0 or 0.25mg Cr/kg DM, -Cr or + Cr, respectively). Treatments consisted of the addition of: 1) sulfate TM (STM; 90, 40, and 18mg/kg DM of Zn, Mn, and Cu, respectively), 2) STM and 0.25mg Cr/kg DM from Cr Prop, 3) hydroxychloride TM (HTM; 90, 40, and 18mg/kg DM of Zn, Mn, and Cu, respectively), and 4) HTM and 0.25mg Cr/kg DM from Cr Prop. Each treatment consisted of 10 replicate pens with 10 steers per pen. Body weights were obtained on consecutive days at the initiation and termination of the 154-d study. Steers were fed a steam-flaked corn-based finishing diet. Ractopamine hydrochloride was fed for the last 31 d of the study. Ruminal fluid and blood samples were obtained from one steer per pen on days 28 and 84 for ruminal volatile fatty acids (VFA) and plasma TM and glucose analysis. Steers were slaughtered at the end of the study and individual carcass data were collected. No Cr × TM source interactions (P = 0.48)were detected. Steers supplemented with HTM had greater (P = 0.04) hot carcass weight (HCW), dressing percentage (DP), longissimus muscle (LM) area, and USDA yield grade (YG), and tended (P = 0.12) to have greater average daily gain (ADG) than those receiving STM. Average daily gain, gain:feed, dressing percentage, and longissimus muscle area were greater (P = 0.04) for + Cr steers compared to-Cr steers. Hot carcass weight tended (P = 0.06) to be greater for + Cr steers. Ruminal acetate concentrations at 28 d were lesser (P = 0.01) for HTM vs. STM steers, and greater (P = 0.04) for + Cr steers compared to-Cr steers. Plasma concentrations of Zn, Cu, and Mn were not affected by TM source or Cr supplementation. Steers supplemented with Cr had greater (P = 0.05) plasma glucose concentrations than-Cr steers at 28 but not at 84 d. Results of this study indicate replacing STM with HTM improved carcass characteristics in finishing steers, and Cr Prop supplementation improved steer performance and carcass characteristics.

The effects of dietary net energy on grow-finish performance and carcass characteristics of male market pigs managed with immunological castration (Improvest).

The objective was to determine the effects of dietary net energy (NE) during the grow-finish period on live performance and carcass characteristics of intact male pigs managed with immunological castration (Improvest) compared with physically castrated (PC) male pigs. The 101-d study began when 1,008 pigs (504 intact male pigs and 504 PC male pigs; 10wk old) were allocated by weight to 48 pens with 21 intact males or 21 PC males per pen. Three dietary NE treatments were fed to pigs using five dietary phases (dietary programs were formulated according to standardized ileal digestible lysine requirements of Improvest males or PC males) to provide an average of 2,212 kcal/kg (low NE), 2,337 kcal/kg (medium NE), or 2,462 kcal/kg (high NE). The experiment was designed and analyzed as a 2 × 3 factorial with main effects of Improvest management and NE. For the overall study period, there were no significant interactions between Improvest management and NE (P ≥ 0.19) for average daily feed intake (ADFI), average daily gain (ADG), or gain:feed (G:F). There were also no significant interactions between Improvest management and NE (P ≥ 0.06) for carcass characteristics. Improvest males consumed less feed (5.3% lower ADFI; P < 0.01), grew faster (5.1% greater ADG; P < 0.01), and were more efficient (11.2% greater G:F; P < 0.01) compared with PC males. Hot carcass weight (HCW) did not differ (P = 0.16) between Improvest males and PC males (attributed to 1.6 percentage unit lower dressing percentage for Improvest males; P < 0.01); however, Improvest males were leaner (0.9mm less backfat and 0.65% greater predicted lean yield; P < 0.01) compared with PC males. For the overall study period, pigs fed low NE and medium NE diets consumed 7.5% and 4.6% more feed (P < 0.01) than pigs fed high NE diets, respectively, and pigs fed low NE diets grew 1.7% slower (P < 0.02) than pigs fed medium NE and high NE diets. This resulted in pigs fed low NE diets having 4.4% lower G:F compared with pigs fed medium NE and 8.6% lower G:F compared with pigs fed high NE diets (P < 0.01). Pigs fed low NE had 3.0kg lighter (P < 0.01) HCW compared with medium NE, while high NE had intermediate HCW that did not differ from the other two treatments. Overall, typical Improvest response levels for live performance and carcass characteristics when compared with PC males were achieved for each of the NE treatments evaluated in this study.

Effects of zinc supplementation and implant abscess on the immune system and growth performance of growing beef steers.

Seventy-two Angus-cross steers (261 ± 14kg) were utilized to determine the effects of supplemental Zn sulfate on growth, trace mineral status, circulating immune cells, and functional innate immune responses. Steers were stratified by weight and implanted with a Component E-S with Tylan implant (Elanco Animal Health, Greenfield, IN) on day 0. Dietary treatments included: control (CON; no supplemental Zn), Zn100 (100mg supplemental Zn/kg DM), and Zn150 (150mg supplemental Zn/kg DM). Analyzed dietary concentrations of Zn were 58, 160, and 207mg Zn/kg DM, respectively. On days 13 and 57, blood from nine steers per treatment was collected for immune analyses (cell phenotyping and response to stimulus). On day 16, implant abscesses were evaluated by palpation and visual appraisal. Sixty percent of steers had abscesses; however, there were no differences in abscess prevalence due to treatment (P = 0.67). Data were analyzed as a split-plot design using the Mixed procedure of SAS 9.4 (Cary, NC) with effects of dietary treatment, abscess, and their interaction. There was a tendency (treatment × abscess; P ≤ 0.09) for steers without abscesses to have greater average daily gain (ADG; treatment × abscess P = 0.06) and gain:feed (G:F; treatment × abscess P = 0.09) from d 14 to 27 in CON and Zn100 while within Zn150 steers without abscesses tended to have lesser ADG and G:F than abscessed steers. There were no other treatment × abscess effects for growth performance, but steers with abscesses tended to have decreased final body weight (P = 0.10) and overall G:F (days 0 to 57; P = 0.08). There was no interaction of treatment and abscess on immune cell populations on days 13 or 58 (treatment × abscess P ≥ 0.11). On day 13, Zn150 steers had increased CD45RO + gamma delta (P = 0.04) T cells. Abscessed steers had increased CD21 + B cells (P = 0.03) and tended to have increased CD21 + (P = 0.07) and CD21 + MHCIIhi (P = 0.07) B cells in circulation. This study shows zinc supplementation and implant abscesses can alter the immune system and growth performance of growing beef steers.

The effects of dietary net energy on grow-finish performance and carcass characteristics of market gilts managed with immunological suppression of ovarian function and estrus (Improvest).

The objective was to determine the effects of net energy (NE) during the grow-finish period on live performance and carcass characteristics of market gilts managed with immunological suppression of ovarian function and estrus (Improvest®; IMP) compared with market gilts not managed with Improvest (CON). The 104-d study began when 1,008 gilts (11wk old; average starting weight of 30.8kg) were allocated by weight to 48 pens with 21 gilts/pen. Half of the pens were randomly selected to be managed with Improvest while the other half of the pens were not managed with Improvest. Three dietary programs differing in their NE were formulated over five dietary phases (according to standardized ileal digestible lysine requirements) to provide an average of 2,218 kcal/kg (low NE), 2,343 kcal/kg (medium NE), or 2,468 kcal/kg (high NE). The experiment was designed as a 2 × 3 factorial with main effects of Improvest management and NE. For the overall study period, there were no significant interactions (P ≥ 0.20) for average daily feed intake (ADFI), average daily gain (ADG), or Gain:Feed (G:F). There were also no significant interactions between Improvest management and NE (P ≥ 0.30) for carcass characteristics. However, IMP gilts consumed more feed (6.8% greater ADFI; P < 0.01), grew faster (5.0% greater ADG; P < 0.01), were less efficient (1.8% lower G:F; P < 0.01), heavier (3.5kg hot carcass weight; P < 0.01), and fatter (1.9mm greater backfat thickness and 1.26% less predicted lean carcass yield; P < 0.01). No difference (P = 0.21) in carcass dressing percentage between IMP and CON gilts was reported. For the overall study period, gilts fed low NE and medium NE diets consumed more feed compared with gilts fed high NE diets (6.8% more ADFI for low NE and 5.7% more for medium NE; P < 0.01), and gilts fed low NE diets grew 2.5% slower (P < 0.01) than gilts fed medium NE diets, while gilts fed high NE diets were intermediate and not different from the other NE treatments. This resulted in gilts fed Low NE diets being the least efficient (3.8% lower G:F than medium NE and 7.1% lower G:F than High NE; P < 0.01). Overall, these data indicate that typical Improvest response levels were sustained at each of the NE treatments evaluated in this study as there were no significant interactions for Improvest management and NE; however, consideration should still be provided to the known production impacts of low NE diets.

The impact of sire breed on feedlot performance and carcass characteristics of beef × Holstein steers.

Dairy herds are mating a portion of cows to beef cattle semen to create a value-added calf. Objectives of this study were to compare the feedlot performance and carcass characteristics of beef × Holstein steers by breed when sires represented bulls with commercially available semen. Three groups of single-born, male calves (n = 262) born to Holstein dams on 10 Pennsylvania dairies were sourced during 3 yr. Steers were sired by seven beef breeds: Angus, Charolais, Limousin, Hereford, Red Angus, Simmental, and Wagyu. Steers were picked up within a week of age and raised at two preweaned calf facilities until weaning (8 ± 1wk of age) under similar health and management protocols. Steers were then transported to a commercial calf growing facility where they were managed as a single group until 10 ± 2 mo of age when they were moved to be finished at the Pennsylvania Department of Agriculture's Livestock Evaluation Center feedlot. Groups of steers were selected for slaughter based on body weight. Carcass characteristics were evaluated by trained personnel and a three-rib section of the longissimus muscle (LM) was collected from each carcass for Warner-Bratzler shear force (WBSF) evaluation and intramuscular fat determination. Steers sired by all sire breeds except for Limousin had greater average daily gain (ADG; 1.62 to 1.76kg/d) than Wagyu × Holstein steers (1.39kg/d; P < 0.05). Angus-sired steers had an 8.6% greater ADG than Red Angus-sired steers (P < 0.05). Angus, Charolais (1.73kg/d), and Simmental-sired steers (1.68kg/d) also had greater ADG than Limousin-sired steers (1.55kg/d; P < 0.05). Wagyu × Holstein steers spent 5 to 26 more days on feed (P < 0.05) than Limousin × Holstein, Simmental × Holstein, Angus × Holstein, and Charolais × Holstein steers. Angus and Charolais-sired steers were also on feed for 19 and 21 d fewer, respectively, than Limousin-sired steers (P < 0.05). Red Angus-sired steers had greater marbling scores than Simmental and Limousin-sired steers and Angus and Charolais-sired steers had greater marbling scores than Limousin-sired steers (P < 0.05). Angus, Limousin, and Hereford-sired steers produced the most tender LM as evaluated by WBSF; Angus-sired carcasses (3.82kg) were more tender than Charolais (4.30kg) and Simmental-sired carcasses (4.51kg; P < 0.05). Limousin and Hereford-sired steers (3.70 and 3.83kg, respectively) also had more tender steaks than Simmental-sired steers.

Effects of dietary supplementation of a blend of Saccharomyces cerevisiae, multiple live probiotic bacteria, and their fermentation products on performance, health, and rumen bacterial community of newly weaned beef steers during a 56-d receiving period.

We examined the effects of a blend of Saccharomyces cerevisiae, multiple live probiotic bacteria, and their fermentation products on performance, health, and the ruminal bacterial community of newly weaned beef steers during a 56-d receiving period. Forty newly weaned Angus crossbred steers (221 ± 25.6kg BW; 180 ± 17 d of age) were stratified by body weight (BW) into four pens (10 steers per pen) such that each pen had a similar average BW at the beginning of the experiment. The pens were randomly assigned to receive a corn silage basal diet (CON; n = 20) or the basal diet supplemented with 9g/steer/d of PRO feed additive (PRO; n = 20). The PRO additive is a blend of S. cerevisiae and the fermentation products of Enterococcus faecium, Bacillus licheniformis, B. subtilis, Lactobacillus animalis, and Propionibacterium freudenreichii. The DMI and water consumed were monitored using the GrowSafe intake nodes and custom flow meters, respectively. BWs were recorded weekly to calculate average daily gain (ADG). Before morning feeding, 10mL of blood was taken from each steer on days 0-7, and thereafter weekly for analyses of immune cells, plasma glucose, and NEFAs. On day 56, rumen fluid samples (200mL each) were collected from all the steers for microbiome analysis. Over the 56-d receiving period, the supplemental PRO had no effects on DMI, water intake, or ADG. However, compared to CON, beef steers fed supplemental PRO tended to have greater ADG (P = 0.08) and BW (P = 0.07) during the first 14 d of the study. There was a treatment × day interaction (P ≤ 0.05) for WBC, neutrophils and monocytes over the 56 d such that beef steers fed supplemental PRO had lower blood concentrations on certain days during the first 7 d after weaning, indicating reduced inflammation or stress response. The results of the rumen microbiome analysis revealed that the relative abundance of complex fiber degrading or obligate proton-reducing bacterial genera such as Bacteroides, Ruminococcus gauvreauii group, Desulfovibrio, Syntrophococcus, and Acetitomaculum were greater (P ≤ 0.05) in beef steers fed supplemental PRO compared to CON. This study demonstrated that dietary supplementation of PRO improved the growth performance, reduced stress or inflammatory response during the initial days after weaning, and altered the ruminal bacterial community toward increased relative abundance of bacterial genera associated with improved rumen function.

Individuality of calves: Linking personality traits to feeding and activity daily patterns measured by precision livestock technology

Animal personality has established connections with animal performance, resilience, and welfare which are related to stable behavioral patterns. Precision livestock technologies introduce the opportunity to measure these behavior patterns automatically and noninvasively. Thus, the primary aim of this study was to determine if personality traits in dairy calves measured via standardized personality assessments were associated with activity measured via a commercially available accelerometer. Secondary aims of this study were to investigate if personality traits were associated with feeding behaviors measured via an automatic feeding system (AFS) and with average daily gain (ADG). We characterized personality traits of Holstein calves (n = 49) utilizing standardized personality (novel environment, novel person, novel object, and startle) tests. Behaviors from these tests were summarized and 3 factors were extracted from a principal component analysis to represent calf personality traits: fearful, active, and explorative. Factor scores were regressed against behaviors from the accelerometer and AFS and with ADG. We found that calves that were more active were associated with taking more steps in the home environment, consuming more calf starter, and with reaching the benchmark of 1 kg of starter consumed in a day at a younger age. The trait active was also associated with greater ADG throughout the study. In addition, calves that were more explorative in the personality tests were associated with less starter consumed and lower ADG specifically during the weaning period. The findings of this research contribute to the existing literature by further establishing the links between personality traits and the daily behavioral patterns and performance of young calves. This study suggests the potential for using precision technology to assess and characterize personality traits, thereby enhancing their practical applicability on farms. Future research should focus on evaluating how personality traits, as measured through standardized assessments and precision technologies, correlate with deviations in behavior observed in dairy calves during stressors.