Translational Animal Science最新文献

The primary objective of this experiment was to evaluate the effects of a growth-hormone implant (Revalor-G, Merck Animal Health., Rahway, NJ, USA) and tannin supplementation (Silvafeed BX, Silva Team, San Michele Mondovi CN, Italy) on enteric methane (CH₄) emissions and estimated nitrogen (N) excretion in grazing steers. Steers (n = 20; initial body weight [IBW] = 343 ± 14 kg) were acclimated to use a portable automated head-chamber system (AHCS) to measure CH₄ and a SmartFeed Pro automated feeder for dietary supplementation (C-Lock Inc., Rapid City, SD, USA). After the training period, steers were randomly assigned to a 2 × 2 factorial arrangements of treatments, with 2 levels of growth-hormone implants, no-implant (NO-IMP) or implanted (IMP), and 2 levels of tannin supplementation, no tannin supplementation (NO-TAN) or tannin supplementation (TAN). This created 4 treatment groups: (1) NO-TAN and NO-IMP, (2) TAN and NO-IMP, (3) IMP and NO-TAN, and (4) TAN and IMP. Tannin was offered daily at 0.30% dry matter intake (DMI) through 0.5 kg/hd/d sweetfeed supplement (Sweetfeed Mix, AgFinity., Eaton, CO, USA) with a targeted tannin intake at 48 g/hd/d. No (P ≥ 0.05) implant × tannin interaction was detected for any dependent variable, so only the main effects of implant (NO-IMP vs. IMP) and tannin supplementation (NO-TAN vs. TAN) are discussed. Implant status did not affect (P ≥ 0.56) final body weight (FBW) or average daily gain (ADG) during the 90 d grazing period. There was no effect (P ≥ 0.15) of growth implant on CH₄ production or emission intensity (EI; g CH₄/kg gain). Additionally, IMP steers tended (P ≤ 0.08) to have less CH₄ yield (MY; g CH₄/g DMI) and higher blood urea nitrogen (BUN) than NO-IMP steers. Tannin supplementation did not impact (P ≥ 0.26) FBW or ADG. However, NO-TAN steers tended (P = 0.06) to have a greater total DMI than steers supplemented with tannin. No effect (P ≥ 0.22) of tannin supplementation was observed for CH₄ production and EI. Nitrogen utilization as measured through BUN, urine N, fecal N, or fecal P was similar (P ≥ 0.12) between TAN and NO-TAN animals. The findings indicate that low-level dietary supplementation to reduce enteric emissions is difficult in grazing systems due to inconsistent animal intake and that growth implants could be used as a strategy to improve growth performance and reduce EI of steers grazing improved pasture.

The objective of this study was to evaluate growth and reproductive performance of heifers developed using 3 different winter systems in the midwestern U.S. Spring-born heifers (n = 1,156; 214 d of age; SD ± 17 d) were used in a 3-yr study to evaluate performance in winter development systems, which utilized cover crop (CC) and corn residue grazing. Heifers were assigned to 1 of 3 treatments: grazing corn residue with 0.77 kg/d dried distillers grains (CD) or 1.69 kg/d wheat midds (CW) supplementation followed by a grower ration in the drylot, or grazing late summer planted oat-brassica CC followed by corn residue grazing with 0.35 kg/d dried distillers grains supplementation (CC). Supplementation during the corn residue phase was targeted to result in a common body weight (BW) (276 kg; ~45% of mature BW) by the end of the winter development period. Grazing of corn residue (CD and CW) and CC began in early November. After 63 d, heifers assigned to CC were moved to corn residue; on day 77 heifers assigned to CD and CW began receiving a grower ration in the drylot. In mid-February (day 98), heifers were comingled and managed in a single group. Breeding season began in June and lasted for 29 d. The ADG of heifers assigned to CC when grazing CC (days 1 to 63) was greater (0.76 kg/d; P < 0.01) than those assigned to CD or CW (0.58 kg/d and 0.49 kg/d, respectively). Gain during the last 35 d of the winter period for heifers assigned to CC (0.36 kg/d) was less (P < 0.01) than those assigned to CW (0.49 kg/d) but not different from CD heifers (0.41 kg/d). Overall (days 1 to 98), winter ADG was greater (P < 0.05) for heifers assigned to CC (0.62 kg/d) than CD (0.53 kg/d) or CW (0.50 kg/d), which did not differ (P = 0.42). Percent of mature BW in May (27 d pre-breeding) was greater (P < 0.01) for heifers assigned to CC (52%) than for those on CD and CW (50%), which did not differ (P = 0.64). Pregnancy rates were affected by treatment (P < 0.03), with heifers assigned to CC (76%) being greater than CW (64%) and CD heifers being intermediate (70%). When accounting for the differences in cost and the value of open and bred heifers, the economic return tended to differ (P = 0.07) among treatments, with CC and CW not differing (P ≥ 0.20) from CD but return for CC being $73 greater than CW (P = 0.02). Utilizing oat-brassica CCs early in the winter followed by a slower rate of gain while grazing corn residue with distillers supplementation appears to be as effective for developing beef heifers in the midwestern U.S. as supplementing distillers grains.

The objective of this experiment was to evaluate the effects of orally administered Megasphaera elsdenii NCIMB 41125 as a microbial supplement in steers abruptly transitioned from a receiving diet with 4% dietary starch (dry matter [DM] basis) to a growing diet with 38% dietary starch (DM basis). Steers (n = 192; initial shrunk body weight [SBW] = 309 ± 20.6 kg) were assigned to microbial supplement treatment in a randomized complete block design. Treatments were control (CON): no microbial supplement prior to diet transition, and (DFM): microbial supplement orally administered prior to diet transition (20 mL of microbial supplement [Lactipro NXT, Axiota Animal Health, Fort Collins, CO] containing 1 × 10¹⁰ colony forming units Megasphaera elsdenii NCIMB 41125). Steers were sourced from a previously conducted 49 d feedlot receiving period experiment and abruptly transitioned from a receiving diet including soybean hulls and wheatlage containing 4% dietary starch (DM basis) to a growing diet including high-moisture ear corn, dry-rolled corn, and wheatlage containing 38% dietary starch (DM basis). Diets were switched on an equal DM intake basis to achieve the abrupt change and steers were fed the 38% starch diet for 49 d until experiment completion. Prior to experiment initiation, steers (n = 72; n = 3/pen) were fitted with wireless rumination tags to track daily activity and rumination time. No differences (P ≥ 0.20) were observed between treatments for final SBW, average daily gain, DM intake, feed efficiency, calculated net energy (NE) for maintenance and gain, or observed-to-expected ratio of NE for maintenance and gain. Additionally, no treatment × day or treatment differences (P ≥ 0.12) were observed for activity or rumination measures. Minutes ruminating and active both differed (P < 0.01) for the main effect of day. Compared to non-supplemented steers, oral administration of Megasphaera elsdenii NCIMB 41125 did not improve growth performance or efficiency of dietary NE utilization in steers transitioned from a receiving diet containing 4% starch (DM basis) to a growing diet containing 38% starch (DM basis).

The objective of this experiment was to assess the influence of arginine (Arg) supplementation in water and/or feed on the growth performance and gastrointestinal health of newly weaned pigs. Two hundred and forty pigs (5.06 kg; PIC, Hendersonville, TN) were randomly allocated into 80 mixed-sex pens (3 pigs/pen) and subjected to a 2 × 4 factorial design. Two levels of Arg were supplemented in water (0% or 8% stock, dosed through a 1:128 proportioner) for the first phase (days 0 to 7), and four dietary arginine levels (0.85, 0.95, 1.05, and 1.15) standardized ileal digestible (SID) Arg to Lysine (Lys) ratios for the first two phases (days 0 to 7 and 7 to 21). All treatments were provided a common diet (0.96 SID Arg:Lys) for the last phase days 21 to 42. One pig per pen underwent a dual sugar absorption test of lactulose at 500 mg/kg and mannitol at 50 mg/kg of body weight (BW) via gastric tube on days 7 and 21 postweaning, with blood plasma collected 4 h later. The pig tested on day 7 was subsequently euthanized for intestinal tissue collection. Pen growth performance and feed disappearance were evaluated for 3 phases: days 0 to 7, 7 to 21, and 21 to 42 postweaning. The statistical analysis used linear models to examine the effects of SID Arg:Lys in the feed, Arg level in water, and their interactions, with pen as the experimental unit. Orthogonal contrasts were used to test the linear and quadratic effects of increasing SID Arg:Lys in the diet. Growth performance during the first period exhibited variability, reflected by negative gain-to-feed (G:F) ratios, caused by the enteric health challenge. Consequently, data were analyzed separately for each phase. Increasing dietary SID Arg:Lys caused a linear improvement (P = 0.04) in final BW (18.47 and 21.90 kg, for 0.85 and 1.15 SID Arg:Lys, respectively). A trend (P = 0.09) suggested a linear impact of dietary SID Arg:Lys on average daily gain during days 21 to 42. Arg supplementation, whether administered through water or diet, did not affect lactulose and mannitol absorption on both days 7 and 21, nor did it alter histological measurements in the collected ileum tissues on day 7 postweaning. In conclusion, increasing dietary SID Arg:Lys increased final BW but had no clear impacts on intestinal health within the parameters measured, potentially impacted by the rotavirus diagnosis in the first week post-wean.

Iowa State University (ISU) provides resources for diversity, equity, inclusion, and belonging (DEI-B) to provide students with a comfortable academic home regardless of their demographics or prior experiences. The objective of this study was to investigate undergraduate students' DEI-B perspectives in the Department of Animal Science at ISU. One survey instrument was developed containing 14 questions that covered demographics, feelings of inclusion, comfort-seeking tools, and ways to improve DEI-B. Answer choices were either multiple choice, 1 to 5 sliding scale, or a specified text sliding scale. Eligible participants were undergraduate students enrolled in Animal or Dairy Science (n = 974). Demographics and comfort-seeking tools will be presented descriptively. Inclusion at the start and after 2 yr were compared using six different linear models. A variable was deemed significant if the P-value was ≤ 0.05. A total of 383 students (88% of total respondents) completed 50% or more of the inclusion questions. Seniors had the highest response rate. More students reported coming from a rural background. Primary species of interest was companion animals. There were no observed differences in feelings of inclusion in classes, with peers, or with faculty for hometown, admission type, ethnic group, and first generation when students started (P ≥ 0.067). There was a difference for primary species of interest (P ≤ 0.011) and with female students feeling less included (P ≤ 0.039). There were no observed differences after 2 yr in classes, with peers, or with faculty for classification year, admission type, or first generation (P ≥ 0.088). Suburban students felt the least included in classes compared to rural and urban students (P ≤ 0.036). Female students felt less included in all three categories (P ≤ 0.017). The majority of students reported having companion animal experience but almost half reported having no experience with livestock prior to ISU. A total of 51% of students said they never considered transferring to another major and 48% indicated that they plan to pursue a career in veterinary medicine. A total of 75% of students felt inclusion could be improved by creating more hands-on opportunities and 60% suggested the department provide more study space. In conclusion, the Department of Animal Science at ISU has some effective inclusion practices but needs to evolve and improve in its DEI-B practices for the undergraduate student population.

This study aimed to assess the effect of Saccharomyces cerevisiae boulardii CNCM I-1079 supplementation during the initial feeding period on the performance of Nellore bulls in a feedlot system. One hundred ninety-eight Nellore bulls were used in a completely randomized block design, with blocking based on weight within each treatment group: light (331.4 kg; 4 pens), medium (349.7 kg; 4 pens), and heavy (362.5 kg; 3 pens). The treatments included CON-a basal diet, and SCB-basal diet plus a probiotic (Saccharomyces cerevisiae boulardii CNCM I-1079; 1.0 × 10¹⁰ CFU/head/d). Experimental diets were administered for the first 42 d (21 d in the step-up phase and 21 d in the finishing diet -870 g concentrate/kg dry matter [DM]). Subsequently, both treatment groups were transitioned to the same basal diet for an additional 76 d, completing 118 d on feed. Linear regression analysis was conducted for dry matter intake (DMI) data. During the initial 42 d, DMI tended to be higher for SCB (P = 0.09); also bulls fed SCB reached the plateau of the curve at 9.17 kg DMI/d earlier (39 d, R² = 0.97) than those fed CON (43 d; R² = 0.96) diets. For the first 42 d, the SCB treatment exhibited higher final weight (393.0 vs. 401.4 kg, P = 0.02), total gain (49.3 vs. 53.5 kg, P = 0.02), daily weight gain (1.124 vs. 1.274 kg, P = 0.02), and G:F (0.174 vs. 0.188, P = 0.04). Over the entire 118-d period, SCB-fed bulls had greater final body weight (509.5 vs. 518.0 kg, P = 0.02), total body weight gain (163.7 vs. 170.3 kg, P = 0.01), and average daily gain (1.366 vs. 1.420 kg, P = 0.01). The feed efficiency of SCB-supplemented bulls was 8.05% higher than CON (P = 0.04), and the final carcass weight was 1.69% greater for animals fed SCB (283.8 vs. 288.6 kg, P = 0.04). Total carcass weight gain (110.9 vs. 114.7 kg) and daily carcass weight gain (0.924 vs. 0.956 kg) tended (P = 0.06) to increase by 3.46% in SCB-fed animals compared with those fed CON. Gain yield, carcass conversion, and carcass yield did not differ between treatments. There were no significant differences in the apparent digestibility of DM, crude protein, neutral detergent fiber, and ether extract between treatments. However, starch digestibility (92.7% vs. 88%) was greater for the control treatment (P < 0.001). Including live Saccharomyces cerevisiae boulardii yeast as a probiotic supplement during the initial 42 d in the feedlot enhanced early-stage growth performance in Nellore bulls. Notably, this supplementation carried over carcass gain over the entire feedlot period.

Fifty-three gilts and fifty-three multiparous (MP) sows were used to evaluate a blended feeding program using gestation and lactation diets during the transition period on changes in sow back fat (BF) depth and BW, blood metabolites, and litter growth performance in the subsequent lactation period. A 2 × 2 factorial experimental design was generated including the factors of parity and feeding program. The MP sows and gilts were assigned to one of two feeding programs on day 104 ± 1 of gestation: 1) 2 kg/d of a standard lactation diet until farrowing when sows received step-up access to the lactation diet until ad libitum access was given on day 4 of lactation (CON) and 2) a dynamic blend of standard gestation and lactation diets that met estimated daily requirements for standardized ileal digestible Lys and net energy according to the NRC (2012) until day 4 of lactation where sows were provided ad libitum access to the lactation diet (TRAN). Litters were standardized to 13 ± 1 piglets within 24-h of birth. In gestation, ADFI was greatest for TRAN-MP sows (interaction; P < 0.05), with greater ADFI for TRAN versus CON sows (main effect; 2.95 vs. 2.13 ± 0.08 kg; P < 0.05). Feeding program did not influence ADFI in lactation, but MP sows had greater ADFI versus gilts (main effect; 5.96 vs. 4.47 ± 0.28 kg; P < 0.001). Immediately after farrowing, TRAN sows had greater BW and BF vs. CON sows, regardless of parity (main effect; 224.1 vs. 215.4 ± 4.1 kg and 17.3 vs. 16.2 ± 0.4 mm, respectively; P < 0.05). At weaning, no feeding program-related differences were observed for BW or BF, but MP sows had thicker BF compared to gilts (main effect; 14.4 vs. 13.4 ± 0.5 mm; P < 0.05). The TRAN-MP sows had heavier piglets at birth compared to all other groups (interaction; P < 0.05) and MP sows had greater litter birth weight and average piglet BW at birth versus gilts (main effect; P < 0.05). No effect of feeding program was observed for piglet BW at weaning. On lactation day 1, serum beta-hydroxybutyric acid and non-esterified fatty acid concentrations were lower for TRAN compared to CON sows (main effect; 12.0 vs. 19.4 ± 7.8 mmol/L and 0.35 vs. 0.57 ± 0.10 mmol/L, respectively; P < 0.05) and serum glucose concentration was greater for TRAN compared to CON sows (main effect; 4.41 vs. 3.88 ± 0.22 mmol/L; P < 0.05), but these differences were no longer detectable at weaning. Therefore, a simple transition feeding program using a blend of a standard gestation and lactation diets reduced energy mobilization by sows in late gestation, with no impact on subsequent lactation performance.

The objective of this study was to determine the efficacy of the direct-fed microbial 10-G upon cattle growth performance, liver and lung health, carcass quality, and yield outcomes, as well as prevalence and enumeration of Salmonella in feces and lymph nodes. Fed beef heifers (N = 1,400; initial shrunk body weight [BW] 343.3 ± 36.2 kg) were blocked by the day of arrival and randomly allocated to one of two treatments (0 [negative control, CON] or 2 g of a direct-fed microbial [10-G] that provided 1 billion CFUs per animal per day of Lactobacillus acidophilus, Enterococcus faecium, Pediococcus pentosaceus, L. brevis, and L. plantarum) with 10 pens per treatment. Recto-anal mucosal fecal samples (RAMs; n = 477) and subiliac lymph nodes (SLNs; n = 479) were collected longitudinally at harvest from 23 to 25 heifers per pen. Data were analyzed using mixed models; pen served as the experimental unit; block and harvest date were random effects. No differences were detected in dry matter intake (P = 0.78), final BW (P = 0.64), average daily gain (P = 0.51), gain to feed (P = 0.71), hot carcass weight (P = 0.54), dressed carcass yield (P = 0.52), 12th rib fat depth (P = 0.13), longissimus muscle area (P = 0.62), calculated empty body fat (P = 0.26), or marbling score (P = 0.82). Distributions of liver scores (P ≥ 0.34), quality grades (P ≥ 0.23), and yield grades (P ≥ 0.11) were also not different between treatments. A tendency was detected for more normal lungs (P = 0.08; 10-G = 65.96%, CON = 61.12%) and fewer inflated lungs at harvest for cattle fed 10-G (P = 0.10; 10-G = 0.29%, CON = 1.16%); other lung outcomes did not differ (P ≥ 0.54). Salmonella prevalence did not differ for RAM samples (P = 0.41; 10-G = 97.74%, CON = 96.82%) or SLN (P = 0.22; 10-G = 17.92%, CON = 13.66%). Salmonella concentration of RAM samples (P = 0.25; 10-G = 3.87 log CFU/g, CON = 3.32 log CFU/g) or SLN (P = 0.37; 10-G = 1.46 log CFU/g, CON = 1.14 log CFU/g) also did not differ between treatments at harvest. These results do not demonstrate any difference in live animal performance, carcass characteristics, or Salmonella carriage for heifers fed 10-G.

The magnitude of physiological responses to a stressor can vary among individual goats within a herd; however, whether these differences can differentially affect meat quality is not known. This study was conducted to determine the influence of the magnitude of epinephrine response (ER) to acute stress on muscle metabolome and meat quality in goats. Male Spanish goats (6 mo old) were transported for 180 min. (N = 75 goats; 25 goats/d) to impose stress. Blood samples were obtained after transport for analysis of physiological responses. Goats were slaughtered using humane procedures and samples were collected for muscle metabolomics and meat quality analyses. The data obtained from blood and muscle/meat analysis were then categorized based on epinephrine concentrations into low (LE), medium (ME), and high (HE) ER groups (n = 12/ER group). The physiological and meat quality variables were analyzed as a Completely Randomized Design in SAS, and metabolomics data were analyzed using R software. Plasma glucose concentrations were significantly high in the HE group, low in the LE group, and intermediate in the ME group (P < 0.05). However, leukocyte counts and cortisol, norepinephrine, blood urea nitrogen, and creatine concentrations were not different among the ER groups. Muscle (Longissimus dorsi) glycogen concentrations (15 min postmortem) were significantly higher (P < 0.05) in the ME and LE groups than in the HE group. However, postmortem Longissimus muscle pH and temperature (15 min and 24 h), 24 h calpastatin and desmin levels, and rib chop color (L*, a*, and b*), cooking loss, and Warner-Bratzler shear force values were unaffected by ER. Targeted metabolomics analysis of Longissimus muscle (15 min) revealed that diacyl phosphatidylcholines (C38:0; 40:6) and sphingomyelin (C20:2) were significantly different (P < 0.05) among the ER groups, with the concentrations of these metabolites being consistently high in the LE group. These differential muscle metabolite concentrations suggest that ER can influence biochemical pathways associated with cell membrane integrity and signaling. ER had a significant effect on dopamine concentrations, with the levels increasing with increasing levels of ER. The results indicate that differences in epinephrine reactivity can influence selected physiological responses and muscle metabolites; however, it does not significantly influence meat quality attributes.

Supplemental methionine (Met) is widely used within the swine industry; however, data are limited regarding the effect of Met sources on carcass cutability and meat quality. The objective was to determine the effects of L-Met (LM, 99%), DL-Met (DLM, 99%), or calcium salt of DL-Met hydroxyl analog (MHA, 84%) in finishing pig diets on carcass characteristics and meat quality. At 9 weeks of age, pigs (N = 240) were allocated to 60 single-sex pens for a four-phase finishing trial that lasted 104 d. Pigs were fed a common grower diet until day 56 where pens were randomly allotted to one of the three experimental diets. For the remaining 7 wk of the finisher phase, pigs (BW = 79.9 ± 0.80 kg) were fed diets containing LM, DLM, or MHA, with the supplemental Met source providing 25% of standardized ileal digestible (SID) Met + cysteine (Cys) requirement based on 65% bioefficacy for MHA in comparison with LM or DLM. One pig per pen was slaughtered at the study conclusion (on day 104), and the left sides of carcasses were fabricated into subprimal cuts to determine carcass-cutting yields. Loin quality including proximate composition and shear force were measured. Hot carcass weight was not different (P = 0.34) between treatments (LM 104.5 kg; DLM 103.0 kg; MHA 101.5 kg), moreover, loin eye area was not different (P = 0.98) between treatments (LM 52.65 cm²; DLM 52.49 cm²; MHA 52.81 cm²). Boneless carcass-cutting yield was not different (P = 0.56) between treatments (LM 54.97 kg; DLM 54.82 kg; MHA 54.52 kg). Loin pH was not different (P = 0.24) between treatments (LM 5.45; DLM 5.48; MHA 5.45). However, drip loss tended to be reduced (P = 0.11) by the DLM treatment (5.58%) compared with LM (7.03%) and MHA (6.68%) treatments. Shear force was not different (P = 0.85) between treatments (LM 3.03 kg; DLM 3.06 kg; MHA 3.10 kg). However, cook loss tended to be reduced (P = 0.06) by the DLM treatment (16.20%) compared with LM (18.18%) and MHA (18.50%) treatments. These data suggest that only minimal differences in carcass cutability and meat quality can be attributed to Met source in finishing pig diets when using 65% bioefficacy for MHA relative to L-Met or DL-Met.