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  • 刊频： Monthly, <Dec. 1975- >
  • NLM标题： J Anim Sci
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  • 1.

    【2hr】Interaction of ergovaline with serotonin receptor 5-HT2A in bovine ruminal and mesenteric vasculature

    包量

    机译 ergovaline与5-HT2A在牛瘤胃和肠系膜血管中的相互作用
    摘要：Ergot alkaloids from endophyte-infected (Epichloë coenophiala) tall fescue (Lolium arundinaceum) induce vasoconstriction. Previous work has shown that serotonin receptor subtype, 5HT2A, is present in bovine ruminal (R) and mesenteric (M) vasculature, plays a role in vasoconstriction, and could be influenced by ergot alkaloids. To determine the influence of ergot alkaloids on 5HT2A, the vasoactivity of an agonist selective for 5HT2A, (4-bromo-3,6-dimethoxybenzocyclobuten-1-yl) methylamine HCl (TCB-2), was evaluated using bovine ruminal and mesenteric arteries and veins (RA, RV, MA, MV) that were exposed to ergovaline (ERV) prior to or during the TCB-2 additions. Ruminal and mesenteric blood vessel segments were collected, cleaned, and cut into 2- to 3-mm cross-sections. Vessel segments were incubated in Krebs-Henseleit buffer containing 0, 0.01 or 1 µM ERV for 2 h prior to TCB-2 dose response or exposed to ERV concentrations simultaneously during TCB-2 dose response. For the dose response portion of the study, vessels were suspended in a multimyograph containing 5 mL of continuously oxygenated Krebs–Henseleit buffer and equilibrated to 1 g tension for 90 min. Vessels were exposed to increasing concentrations of TCB-2 every 15 min and contractile response data were normalized as a percentage of the maximum contractile response induced by 120 mM KCl reference. Analysis of variance was evaluated separately for each vessel and each ERV exposure experiment using the mixed models procedure of SAS for effects of TCB-2 and ERV concentrations. All blood vessels with previous ERV exposure had significantly lower contractile responses to TCB-2 (P < 0.01). All blood vessels with simultaneous exposure to 1 µM ERV had higher (P < 0.01) contractile responses at lower concentrations of TCB-2. Simultaneous ERV addition at 1 × 10−4 M TCB-2 did not affect contractility of RV, MA, MV (P > 0.05), but decreased contractility of RA (P < 0.01). These results indicate that ergopeptine alkaloid exposure influences contractility of bovine ruminal and mesenteric blood vessels through serotonin receptor subtype 5HT2A by acting as both an agonist and antagonist. Additional work is needed to determine if ergot alkaloids like ERV simply occupy receptor binding sites competitively, or influence receptor internalization to cause the observed divergent responses.
  • 2.

    【2hr】Leukocyte coping capacity chemiluminescence as an innovative tool for stress and pain assessment in calves undergoing ring castration

    包量

    机译 白细胞应对能力化学发光作为一种新工具，用于评估去势小牛的压力和疼痛
    摘要：Pain and stress assessment in animals is considered an imperative issue and also a difficult challenge. Unfortunately, no gold standard technique for pain and stress assessment in animals has been validated nowadays. A new tool to assess stress in animals consists of measuring the leukocyte coping capacity (LCC). The aim of this study was to evaluate the whole-blood LCC chemiluminescence as an innovative tool for stress and pain assessment in the bovine species undergoing ring castration. Twenty 2-mo-old male mix-breed Piemontese-Angus-Belgian Blue calves (Bos taurus) weighing 90 ± 4 kg were used. The animals were randomly allocated in 2 groups composed of 10 subjects each as follows: ring castration group (CAS) and sham castration group (SHAM). Blood drawing, scrotal and perineal temperature recording, scrotal lesion score, pain assessment, and LCC Chemiluminescence were performed at different time points, which were as follows: 1 h before castration/sham (−1 h), 30 min postcastration/sham (30 min), 3 d postcastration/sham (3 d), 7 d postcastration/sham (7 d), 14 d postcastration/sham (14 d). Results showed that in CAS LCC values significantly increased (P < 0.05) at 3 d and decreased at 7 d, whereas in SHAM, LCC values did not significantly vary between the study times. Significant differences in LCC values between CAS and SHAM were seen at 7 d (P < 0.0001). In the CAS group, scrotal lesion was scored as 0, 0, 3.8, 2.7, and 0.2 at −1 h, 30 min, 3 d, 7 d, and 14 d, respectively, whereas in SHAM, its score was 0 at every time point. Perineal temperatures did not vary throughout all the study times in both CAS and SHAM. Differences among the 2 groups were noted in scrotal temperatures only at 3, 7, and 14 d (P < 0.05). In CAS, the percentage of animals which obtained a pain score ≥ 1 was: 10% at −1 h, 30% at 30 min, 20% at 3 and 7 d, and 10% at 14 d, whereas in SHAM, no pain signs were noted at any time point. No significant difference between CAS and SHAM was recorded in cortisol blood level at any time point. No stress leukogram nor variation in neutrophil/lymphocyte ratio was noted at any of the time points in both CAS or SHAM. Our results suggest that ring castration might cause long-lasting pain in calves, but its magnitude is not easily detected by conventional methods. We argue that whole-blood LCC chemiluminescence might be a useful tool for detecting pain and stress in calves undergoing ring castration.
  • 3.

    【2hr】Additivity of apparent and standardized ileal digestibility of amino acid determined by chromic oxide and titanium dioxide in mixed diets containing wheat and multiple protein sources fed to growing pigs

    包量

    机译 由氧化铬和二氧化钛测定的含小麦和多种蛋白质来源的混合日粮中氨基酸的表观和标准化回肠消化率的加性
    摘要：The aim of this study was to investigate the additivity of apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in mixed diets containing wheat, canola meal (CM), meat and bone meal (MBM), and sorghum distillers’ dried grains with solubles (DDGS) fed to pigs with chromic oxide (Cr2O3) and titanium dioxide (TiO2) as digestibility index markers. Four diets were prepared to contain wheat, CM, MBM, or DDGS as a sole source of nitrogen; three mixed diets were prepared to contain wheat, CM, and MBM; wheat, MBM, and DDGS; or wheat, CM, MBM, and DDGS; also, a nitrogen-free diet was prepared to estimate the basal ileal endogenous losses (BEL) of CP and AA. Both Cr2O3 and TiO2 were incorporated at 5 g/kg into each diet. Sixteen barrows (initial body weight = 34.7 ± 0.6 kg) surgically fitted with T-cannulas at the distal ileum were allotted to a duplicate 8 × 4 Youden square design with eight experimental diets and four periods. During each 7-d period, the ileal digesta was collected for 2 d after a 5-d adaptation, and the AID and SID of CP and AA were determined using Cr2O3 or TiO2 as marker. There was no interaction between diet and marker type for both AID and SID of CP and AA. Similar BEL, AID, and SID of CP and AA were determined by Cr2O3 and TiO2. In the wheat–CM–MBM diet, the measured AID of CP and most AA determined with Cr2O3 or TiO2 were not different from the predicted values, which was determined based on the measured AID values in wheat, CM, and MBM. In the wheat–MBM–DDGS diet, the measured and predicted AID of CP and seven indispensable AA differed (P < 0.05) using Cr2O3 as marker, and the measured and predicted AID of CP and four indispensable AA differed (P < 0.05) using TiO2 as marker. The measured AID of CP and most indispensable AA were greater (P < 0.05) than predicted AID regardless of marker type for the wheat–CM–MBM–DDGS diet. The measured SID of CP and indispensable AA were consistent with the predicted values, except Lys in the wheat–CM–MBM diet using either marker and His in the wheat–MBM–DDGS diet with Cr2O3 as marker. In conclusion, more accurate prediction of ileal digestibility of CP and AA was achieved using SID rather than AID in mixed diets containing wheat, CM, MBM, and DDGS. The determination of endogenous loss, AID, and SID of CP and AA were not affected by marker type in this study. In addition, the additivity of AID and SID of CP and most indispensable AA in mixed diets was not affected by marker type.
  • 4.

    【2hr】Effects of dietary pectin on the profile and transport of intestinal bile acids in young pigs

    包量

    机译 日粮果胶对幼猪肠道胆汁酸分布和转运的影响
    摘要：Pectin has been known to lower circulating cholesterol by interacting with bile acid (BA) metabolism. The current study was aimed to investigate intestinal BA transport at the molecular level in a pig model. Twelve young pigs (11.05 ± 0.11 kg) were randomly divided into 2 groups and fed corn–soybean meal diets with either 5% pectin or cornstarch for 72 d. In pigs fed with pectin, total cholesterol and low-density lipoprotein cholesterol (LDL-C) were lowered but high-density lipoprotein (HDL-C) was increased (P < 0.05). Serum triglycerides tended to be lower in the pectin-fed animals (P = 0.093), whereas no change was noted in serum total bile acid. Along the length of the intestine, the size and composition of BA pools vary. The ratio of primary, secondary, taurine-conjugated, and glycine-conjugated BAs in the ileal pool was about 46:15:9:30, whereas it was 28:61:1:11 in the cecum and 22:65:3:9 in the colon (P < 0.05). In the feces, lithocholic acid and ursodeoxycholic acid (UDCA) made up of over 97% of the total BA pool. Overall, the ileum had the greatest expression of farnesoid X receptor (FXR) and apical sodium-coupled bile acid transporter (ASBT) than the duodenum, jejunum, cecum, and colon (P < 0.05), whereas organic solute transporters α/β (OSTα/β) gene expression was peaked in the ileum and jejunum (P < 0.05). Expression multidrug resistance protein 2 (MRP2) gradually decreased towards the end of the intestine (P < 0.05). Greater expression of G protein-coupled bile acid receptor and multidrug resistance protein 3 (MRP3) was found in the cecum and colon (P < 0.05). In pigs fed with 5% pectin, only cecal UDCA (P = 0.097) and hyocholic acid (P = 0.088) showed a decreasing tendency. But FXR, ASBT, and MRP2 were upregulated in the ileum and FXR, OSTα/β, MRP2, and MRP3 in the cecum of PEC-fed pigs (P < 0.05). Liver enzymes involved in BA biosynthesis (CYP7A1, CYP27A1, bile acid-CoA synthase, and bile acid-CoA:amino acid N acyltransferase) were not affected by pectin consumption. In conclusion, the abundant distribution of BA transporters and the greater BA pool size suggests the ileum as the major site for intestinal BA reabsorption in pigs. In the ileum, pectin increased in-and-out BA transport on the apical membrane by increasing ASBT and MRP2, but it increased the overall BA transport in the cecum by increasing OSTα/β and MRP3.
  • 5.

    【2hr】Sow stress levels and behavior and piglet performances in farrowing crates and farrowing pens with temporary crating

    包量

    机译 母猪分娩的板条箱和产仔猪的应激水平，行为和仔猪性能
    摘要：Farrowing pens with temporary crating have been developed as a compromise between conventional farrowing crates and pens to better accommodate the welfare of both sow and piglets during lactation. However, not much is known about the behavioral and physiological consequences of early removal of confinement on the sow and piglets during lactation. The aim of this study was to assess the effects on sow and piglet performance of temporary crating until 3-d postpartum at 2 times points, immediately after confinement removal and 25 d into lactation. Sows were crated from 5-d prepartum either to weaning (permanently crated—PC group; N =14) or to D3 (83.0 ± 1.3 h) postpartum (Temporarily crated - TC group N = 13). Sow postural changes, activity, cortisol and IgA concentrations, and piglet body weight gain and behavior were assessed on D4 and on D25 postpartum, whereas piglet mortality was assessed throughout lactation. Data were analyzed using PROC GLM and PROC GENMOD of SAS. On D4 postfarrowing, TC sows were more active (10.9% vs. 7.1%; SEM: 0.8; P = 0.002), rolled more frequently (21.3% vs. 14.4%; SEM: 1.6; P = 0.008), and had lower IgA concentrations (139.7 vs. 75.2 µg/mL; SEM: 20.3; P = 0.040) than PC sows. No effects of housing were found (P > 0.05) on standing-to-lying movement or cortisol concentrations. No differences for any variables were found (P > 0.05) on D25. Mortality, body weights, and activity levels at the udder or in the pen of pigs born to PC sows did not differ (P > 0.05) from those of piglets born to TC sows on D4 nor on D25. This study indicates that removal of confinement on the 4th-d postpartum may have had small short-term positive effects on sow behavior and stress levels (as measured by IgA), and that it did not impair piglets’ behavior and performance during lactation. Therefore, this work suggests that temporary crating limited to the first 3-d postpartum might be a feasible alternative to improve welfare under intensive production conditions.
  • 6.

    【2hr】Feed batch sequencing to decrease the risk of porcine epidemic diarrhea virus (PEDV) cross-contamination during feed manufacturing

    包量

    机译 饲料批次测序可降低饲料生产过程中猪流行性腹泻病毒（PEDV）交叉污染的风险
    摘要：Feed has been identified as a vector of transmission for porcine epidemic diarrhea virus (PEDV). The objective of this study was to determine if feed batch sequencing methods could minimize PEDV cross-contamination. Porcine epidemic diarrhea virus-free swine feed was manufactured to represent the negative control. A 50 kg feed batch was mixed in a pilot scale feed mill for 5 min, sampled, then discharged for 10 min into a bucket elevator and sampled again upon exit. Next, a pathogenic PEDV isolate was used to inoculate 49.5 kg of PEDV-free feed to form the positive control. The positive control was mixed, conveyed and sampled similar to the negative control. Subsequently, 4 sequence batches (sequence 1 to 4) were formed by adding a 50 kg batch of PEDV-negative feed to the mixer after the prior batch was mixed and conveyed; all sequences were mixed, conveyed, and sampled similar to the negative and positive control batches. None of the equipment was cleaned between batches within a replicate. This entire process was replicated 3 times with cleaning the feed mill between replicates. Feed was then analyzed for PEDV RNA by real-time reverse transcriptase semiquantitative polymerase chain reaction (rRT-PCR) as measured by cycle threshold (Ct) and for infectivity by bioassay. Sequence 1 feed had higher (P ˂ 0.05) rRT-PCR Ct values than the positive batch and sequence 2 feed had higher (P ˂ 0.05) Ct values than sequence 1, regardless of sampled location. Feed sampled from the mixer from sequence 2, 3, and 4 was rRT-PCR negative whereas feed sampled from the bucket elevator was rRT-PCR negative from sequence 3 and 4. Bioassay was conducted using 66 mixed sex 10-d-old pigs confirmed negative for PEDV allocated to 22 different rooms. Pigs were initially 10-d old. Control pigs remained PEDV negative for the study. All pigs from the mixer positive batch (9/9) and bucket elevator positive batch (3/3) were rRT-PCR positive on fecal swabs by the end of the study. One replicate of pigs from mixer sequence 1 was rRT-PCR positive (3/3) by 7 dpi. One replicate of mixer pigs from sequence 2 was rRT-PCR positive (3/3) by 7 dpi although no detectable PEDV RNA was found in the feed. The results demonstrate sequenced batches had reduced quantities of PEDV RNA although sequenced feed without detectible PEDV RNA by rRT-PCR can be infectious. Therefore, a sequencing protocol can reduce but not eliminate the risk of producing infectious PEDV carryover from the first sequenced batch of feed.
  • 7.

    【2hr】Energetic efficiency and the first law: the California net energy system revisited

    包量

    机译 能源效率和第一定律：重新审视加利福尼亚的净能源系统
    摘要：Models of energy utilization used in livestock production predict input:output relationships well, for all the wrong reasons. Predictive accuracy in such models is not due to fidelity to biochemistry and laws of thermodynamics, but because they were developed to predict accurately, often with little regard to biochemical consistency. Relatively static linear statistical models limit thermodynamically relevant descriptions of energy utilization, especially maintenance, in growing beef cattle and are inadequate research tools, in either ordinary least squares (OLS) or Bayesian frameworks. Metabolizable energy intake (MEI) at recovered energy (RE) = 0 (MEm) and efficiencies of ME utilization for maintenance (km) and gain (kg) were estimated for 3 independent data sets using OLS or Bayesian frameworks. Estimates of MEm differed (P < 0.05) between OLS and Bayesian estimates and were not unique, indicating model misspecification. Bayesian estimates of MEm were monotonic, positive, and nonlinear f(MEI); the range was from 6.74 to 14.8 Mcal/d. Estimates of km, the ratio of heat energy (HE) at MEI = 0 to MEm, for the 3 data sets averaged 0.590 for OLS solutions, or 0.616 for the first derivative (km, dHE/dMEI for RE = 0) of a first-order function. The first derivative (dHE/dMEI) of the OLS function was > 1.0 for MEI > 22.1 Mcal/d, counter to the laws of thermodynamics and indicated model misspecification. The Bayesian estimate of km (0.420) differed (P < 0.05) from the OLS estimate and was consistent with the efficiency of ATP synthesis. Efficiency of ME use for gain for RE > 0 (kg, OLS solutions) averaged 0.397, solutions were nonunique and single-variable OLS models were misspecified (P < 0.050) for 2 of the 3 data sets. The OLS estimate of kg differed (P < 0.05) from the estimate of kg (0.676) determined in a Bayesian framework; the latter was calculated as dRE/dMEI for RE > 0. For OLS estimates km > kg; for estimates determined in a Bayesian framework km < kg, the former is inconsistent, while the latter is consistent with the thermodynamic favorability of reactions underlying maintenance and gain. Our results show that the use of relatively fixed coefficients of maintenance in current feeding standards, mathematical descriptions of metabolic processes and concepts regarding efficiencies of energy utilization in those systems need modification to be consistent with animal biology and the laws of thermodynamics.
  • 8.

    【2hr】Correlation comparisons among early postmortem loin quality and aged loin and pork chop quality characteristics between finishing pigs from either Duroc or Pietrain sires

    包量

    机译 杜洛克（Doroc）或皮特兰特（Pirtrain）母猪的后期死猪里脊肉质量与成年猪和猪排质量特征之间的相关比较
    摘要：Today, the United States exports 2.2 million tons of pork and pork products annually, representing just over 26% of U.S. pork production. In order to meet specific demands of a growing export market, pork quality and carcass characteristics are now integrated into breeding objectives. Color and marbling are 2 loin quality traits that influence consumer acceptability of pork and while correlations between early and aged ventral quality have been established, it is unclear if those correlations differ between production objectives (meat quality vs. lean growth). Therefore, the objective of this experiment was to compare correlations among early postmortem ventral loin quality characteristics and aged ventral loin and chop quality characteristics between pigs sired by either Pietrain (lean growth) or Duroc (meat quality) boars. Early postmortem (~1 d) quality traits included: instrumental and visual color, marbling and firmness, and loin pH on the ventral surface of the loin. Loins were aged until 14 d postmortem in vacuum packages. Aged quality traits included traits evaluated early as well as Warner-Bratzler shear force (WBSF) and cook loss. Correlations were compared between Pietrain and Duroc-sired pigs using a Fisher’s z-test. Early instrumental lightness (L*) was moderately correlated with aged ventral L* (Pietrain r = 0.47; Duroc r = 0.65) and aged ventral visual color (Pietrain r = 0.42; Duroc r = 0.58). Early ventral visual color was moderately correlated with aged chop L* (Pietrain r = 0.46; Duroc r = 0.60) and aged chop visual color (Pietrain r = 0.45; Duroc r = 0.57). Early visual marbling was strongly correlated (Pietrain r = 0.68; Duroc r = 0.84) with aged chop visual marbling. Within the Duroc-sired pigs, early L* was moderately correlated with aged chop L* (r = 0.64) but only weakly correlated (r = 0.35) within the Pietrain-sired pigs and those correlations differed at P ≤0.02. Within the Duroc-sired pigs, early ventral visual color was moderately correlated with aged pH (r = 0.44) and aged ventral L* (r = 0.57) but only weakly correlated (r ≤ 0.29) within the Pietrain-sired pigs and those correlations differed at P ≤0.03. No early postmortem quality traits were correlated (|r| ≤ 0.34) with WBSF or cook loss for either sire line. In summary, correlations between early and aged postmortem quality traits rarely differed between Duroc- and Pietrain-sired pigs. It is not necessary to account for sire line when relating early and aged quality characteristics.
  • 9.

    【2hr】Genetic analysis of robustness in meat sheep through body weight and body condition score changes over time

    包量

    机译 通过体重和身体状况得分随时间变化对肉羊鲁棒性的遗传分析
    摘要：Animal robustness may be defined as a complex trait characterizing the ability of an individual to be adapted, productive and healthy under contrasted and fluctuating environmental situations. Such a trait is now considered an essential criterion in order to meet the more ambitious goals of farming sustainability. In ruminants, one of the key mechanisms via which robustness is expressed is the capacity to mobilize or restore body reserves (BR) to cope with the challenges of negative energy balances. The objectives of this work were as follows: 1) to estimate the genetic parameters related to BR dynamics in ewes over successive production cycles and 2) to investigate BR management relationships between different physiological stages. For this, historical individual BW and BCS data from 2,920 phenotyped ewes were used for genetic analysis. The changes in BW (∆BW) and BCS (∆BCS) over time were analyzed. Eight physiological stages were considered to investigate these changes over time: mating, early pregnancy, mid-pregnancy, lambing, early suckling, mid-suckling, weaning, and postweaning. The estimated heritability were low for both ∆BW (h2 = 0.13 to 0.18) and ∆BCS (h2 = 0.04 to 0.16). Moderate to high positive genetic correlations (from 0.48 to 0.91) were obtained between BR mobilization phases and between BR accretion phases. Similarly, moderate to high negative genetic correlations (from −0.36 to −0.75) were estimated between the BR mobilization and accretion periods, suggesting that mechanisms driving BR mobilization and accretion processes were genetically correlated. This is the first study in ruminants that demonstrate that the extent and temporal changes in profiles of BR mobilization and accretion are heritable and genetically linked, indicating that such traits could be considered in genetic programs aimed at improving robustness. Nevertheless, further research is needed for a more comprehensive understanding of BR dynamics, notably by including other physiological parameters (i.e., metabolites and hormones) and additional information on the productive and reproductive life of the ewe.
  • 10.

    【2hr】Effects of standardized ileal digestible histidine to lysine ratio on growth performance of 7- to 11-kg nursery pigs

    包量

    机译 标准化回肠可消化组氨酸与赖氨酸的比例对7至11公斤保育猪生长性能的影响
    摘要：Histidine may be the sixth limiting amino acid (AA) in practical nursery diets supplemented with high amounts of feed-grade AA. Therefore, 2 experiments were conducted to determine the standardized ileal digestible (SID) His:Lys ratio requirement estimate for growth performance of 7- to 11-kg nursery pigs. A total of 360 and 350 pigs (DNA 241 × 600, Columbus, NE; initially 7.1 ± 0.31 and 6.6 ± 0.36 kg) were used in Exp. 1 and 2, respectively. There were 5 pigs per pen with 12 replicates per treatment in Exp. 1 and 10 replicates per treatment in Exp. 2. After weaning, pigs were fed a common pelleted diet for 10 d in Exp. 1 and 7 d in Exp. 2. Then, pens were assigned to treatments in a randomized complete block design with body weight (BW) as the blocking factor. Dietary treatments consisted of SID His:Lys ratios of 24%, 28%, 32%, 36%, 40%, and 44% in Exp. 1 and 24%, 28%, 30%, 32%, 34%, 36%, and 42% in Exp. 2. Experimental diets were fed in pellet form for 10 or 14 d in Exp. 1 and 2, followed by a common mash diet for 15 or 14 d, respectively. Data were analyzed using the GLIMMIX and NLMIXED procedures of SAS, fitting data with heterogeneous variance when needed. The competing statistical models utilized were quadratic polynomial, broken-line linear (BLL), and broken-line quadratic. In Exp. 1, increasing SID His:Lys ratio increased (quadratic, P = 0.001) ADG, ADFI, G:F, and day 10 BW. In Exp. 2, ADG, G:F, and day 14 BW increased (quadratic, P = 0.001), and ADFI increased linearly (P = 0.001) with increasing SID His:Lys ratio. The best-fitting model for all response variables analyzed was the BLL. In Exp. 1, requirement estimates were 29.7%, 29.1%, and 29.8% SID His:Lys ratio for ADG, ADFI, and G:F, respectively. In Exp. 2, the SID His:Lys ratio requirement estimates were 31.0% for ADG and 28.6% for G:F. These results suggest that the SID His requirement estimate for growth performance is no more than 31% of Lys and that the SID His requirement of 34% of Lys may be overestimated for 7- to 11-kg pigs.
  • 11.

    【2hr】Amino acid digestibility of corn distillers’ dried grains with solubles with the addition of casein in pigs

    包量

    机译 猪中添加酪蛋白的玉米溶酒用可溶物干燥谷物的氨基酸消化率
    摘要：This experiment was conducted to determine the ileal digestibility of CP and AA in casein by regression analysis and to investigate the effects of casein in experimental diets on the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in corn distillers’ dried grains with solubles (DDGS) fed to pigs. Twenty barrows (initial BW = 50.5 ± 4.46 kg) surgically fitted with T-cannulas at the distal ileum were used. Eighteen pigs were assigned to a triplicate 6 × 3 incomplete Latin Square design with 6 diets and 3 periods. Two pigs were used as replacements. Three diets were prepared to contain 60, 100, or 140 g/kg casein to determine the ileal digestibility of CP and AA in casein by regression analysis, and 2 diets were prepared to contain either 480 g/kg DDGS or 308 g/kg DDGS and 60 g/kg casein. Casein and DDGS were the sources of nitrogen (N) in experimental diets. A N-free diet was prepared based on cornstarch and dextrose. Experimental periods consisted of 5 d of adaptation and 2 d of ileal digesta collection periods. The AID of CP and AA in casein linearly increased (P < 0.01) with increasing concentration of casein in the diets. The SID of indispensable AA in casein ranged from 94.7% (SEM = 1.16) for Ile in pigs fed the diet containing 60 g/kg casein to 103.3% (SEM = 2.21) for Arg in pigs fed the diet containing 100 g/kg casein. Except for Arg, pigs fed the diet containing DDGS and casein had greater (P < 0.001) SID of CP and indispensable AA than those fed the diet containing DDGS without casein. The ileal digestibility of indispensable AA in casein determined by regression analysis ranged from 96.8% (SE = 3.14) for Thr to 103.1% (SE = 4.40) for Arg. The AID and SID of CP and AA for DDGS in the diet containing casein were calculated by difference method using the ileal digestibility of CP and AA in casein determined by regression analysis. The AID of Lys for DDGS in the diet containing casein was greater (P = 0.035) than those without casein; however, the AID of CP and the other indispensable AA, except for Arg, Phe, and Trp, for DDGS in the diet containing casein was less (P < 0.05) than those without casein. The SID of Lys and Phe for DDGS in the diet containing casein was greater (P < 0.05) than those without casein. In conclusion, improved AA composition in semi-purified experimental diets may affect the SID of AA in low-quality protein ingredients.
  • 12.

    【2hr】Effects of orally administered cortisol and norepinephrine on weanling piglet gut microbial populations and Salmonella passage

    包量

    机译 口服皮质醇和去甲肾上腺素对断奶仔猪肠道微生物种群和沙门氏菌传播的影响
    摘要：Stress and anxiety have been associated with changes in the microbiota of the gut and ultimately diminished resistance to pathogens. The objective of this study was to observe intestinal microbiota and susceptibility to Salmonella associated with stress hormones, cortisol (CORT), and norepinephrine (NE), in piglets. At weaning, 90 piglets (15 for a Salmonella challenge) were trained to take the carrier (apple juice) orally. At 2 wk after weaning, pens of piglets were assigned randomly to 1 of 3 treatments: control (CNT), NE, or CORT. Blood samples were collected prior to treatment, then piglets were dosed orally with treatments twice on day 0; at 0800 and 1600 h. Control piglets were administered 6.1 mL of the carrier only, NE pigs were administered 40 mg/mL of NE-bitartrate salt dissolved in the carrier, and CORT pigs were administered 12 mg/mL of hydrocortisone acetate dissolved in the carrier. Jugular blood samples were collected prior to necropsies (n = 5/treatment) at 0800 and 1600 h on day 1, and at 0800 h on days 2, 7, and 14 after treatments were started. A subset of pigs were subjected to a 24-h Salmonella challenge. Jejunal and ileal tissues and jejunal, ileal, cecal, and rectal contents were collected and colonies were counted. Microbial data and blood samples were analyzed using mixed models with fixed effects of treatment and day. Cortisol-treated piglets exhibited a spike in plasma CORT concentrations at 0800 h day 1 (P = 0.001) accompanied by greater concentrations of cecal Escherichia coli (P < 0.05) and a shift in intestinal environment to favor coliforms on day 2 (P < 0.05). Salmonella concentrations from rectal contents tended (P = 0.07) to be suppressed by CORT. Lactic acid–producing bacteria rectal concentrations were greater (P = 0.03) in CORT pigs on 0800 h on day 1 then NE pigs and tended to be greater than CNT (P = 0.09) and were greater on day 14 for both CNT (P = 0.003) and NE (P = 0.02). Norepinephrine spiked in NE piglets at 0800 h on day 1 (P = 0.001), 1600 h day 1 (P = 0.004), through day 2 (P = 0.04). Intestinal environment of NE pigs shifted to favor ileal anaerobes (P ≤ 0.05) and facultative anaerobes (E. coli; P = 0.01) compared to CNT. However, Salmonella concentrations in rectal contents were suppressed by NE compared to CNT (P = 0.05). Oral administration of NE and CORT had the desired effect of increasing concentrations of stress hormones and resulted in microbiome shifts throughout the intestines.
  • 13.

    【2hr】Nutritional composition, gross energy concentration, and in vitro digestibility of dry matter in 46 sources of bakery meals

    包量

    机译 营养成分，总能量浓度和46种烘焙食品来源的干物质的体外消化率
    摘要：Work was conducted to test the hypothesis that the nutritional composition of bakery meal varies depending on where in the United States the meal is produced due to different raw materials being used in the production of the meals. Forty-six samples of bakery meal were collected from feed mills located in the swine producing states in the United States. Based on the state where samples were collected, they were grouped into 5 regions: 1) AL, DE, GA, NC, PA, and VA (10 samples); 2) CO, MO, OK, and TX (10 samples); 3) IN, KY, OH, and TN (8 samples); 4) IA (11 samples); and 5) MN (7 samples). All samples were analyzed for proximate components, GE, AA, carbohydrates, and minerals, and IVDMD and in vitro energy digestibility (IVGED) were also determined. Results indicated that the average concentration of DM was (91.84 ± 1.29%) and there was no difference among regions. The concentration of ash in bakery meal from MN was greater (P < 0.05) than in meals from other regions, but for all other proximate components, no differences among sources were observed. The average concentration (DM basis) of CP (12.20 ± 2.16%), acid hydrolyzed ether extract (AEE, 9.38 ± 1.95%), starch (44.61 ± 5.47%), and NDF (13.77 ± 4.23%) indicated that bakery meal consists of a mixture of food ingredients originating from flour or whole cereal grains and with some high-fiber ingredients such as brans or canola coproducts also included. It also appears that oil or fats were added during production. With the exception of His, no differences among regions were observed for indispensable AA and the average concentrations (DM basis) of Lys, Met, Thr, and Trp were 0.35 ± 0.08%, 0.19 ± 0.03%, 0.38 ± 0.06%, and 0.13 ± 0.03%, respectively. The bakery meals from MN contained more (P < 0.05) Ca than bakery meals from other regions, indicating that limestone may have been added to bakery meal from MN to improve flowability. However, bakery meals from MN and IA contained less (P < 0.05) total P, phytate, and phytate-bound P than bakery meals produced in the states east of the Mississippi River. There were, however, no differences in IVDMD (79.06 ± 6.62%) or of IVGED (74.84 ± 8.20%) of bakery meals among regions. The present results indicate that variations in the chemical composition of bakery meal obtained from different regions in the United States are relatively small and likely without great impact on the nutritional value of the meals, but in vivo digestibility experiments are needed to confirm this hypothesis.
  • 14.

    【2hr】Relationships among carbon dioxide, feed intake, and feed efficiency traits in ad libitum fed beef cattle

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    机译 随意饲养肉牛的二氧化碳，采食量和饲料效率性状之间的关系
    摘要：Angus cattle from 2 beef cattle projects on which carbon dioxide production rate (CPR) was measured were used in this study to examine the relationships among BW, DMI, and carbon dioxide traits of beef cattle fed ad libitum on a roughage diet or a grain-based feedlot diet, and to evaluate potential proxies for DMI and feed efficiency. In both projects, the GreenFeed Emission Monitoring system, which provides multiple short-term breath measures of carbon dioxide production, was used as a tool to measure CPR. The data were from 119 Angus heifers over 15 d on a roughage diet and 326 Angus steers over 70 d on a feedlot diet. Mean (±SD) age, BW, and DMI were 372 ± 28 d, 355 ± 37 kg, and 8.1 ± 1.3 kg/d for the heifers, and 554 ± 86 d, 577 ± 69 kg, and 13.3 ± 2.0 kg/d for the steers, respectively. The corresponding mean CPR was 5760 ± 644 g/d for heifers and 8939 ± 1212 g/d for steers. Other traits studied included carbon dioxide yield (CY; CPR/DMI) and intensity (CI; CPR/BW) and 5 forms of residual carbon dioxide production (RCP), which is a measure of actual minus predicted CPR. Feed efficiency traits studied included feed conversion ratio (FCR) and residual feed intake (RFI). The relationship between CPR and DMI, and between CPR and BW was both positive and linear, for the heifers and also for the steers. For the combined heifer and steer datasets, the R2 for the relationship between CPR and BW, and between CPR and DMI was 0.82 and 0.78, respectively. The correlation between CPR and DMI (r = 0.84 for heifers; r = 0.83 for steers) was similar to that between CPR and BW (r = 0.84 for heifers; r = 0.87 for steers). Most of the carbon dioxide traits were significantly (P < 0.05) correlated with one or both feed efficiency traits. One of the RCP traits (RCPMA) was computed by maintaining metabolic BW (M) and average daily gain (A) in the formula for RFI, but substituting the DMI with CPR. The correlation (r = 0.27) between RCPMA and RFI, though significantly different from zero, was not strong enough for its use as proxy for RFI. On the other hand, a strong correlation (r = 0.73) was obtained between the CPR to gain ratio (CGR) and FCR. This indicates that, where DMI is not available, CPR could be used in its place to compute a feed efficiency trait similar to FCR, since the computation of CGR was similar to that for FCR, except that DMI was substituted with CPR in the FCR formula.
  • 15.

    【2hr】Influence of age at first calving in a continuous calving season on productive, functional, and economic performance in a Blonde d’Aquitaine beef population

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    机译 连续产犊季节第一次产犊的年龄对金发阿基坦大牛种群生产，功能和经济绩效的影响
    摘要：The lifetime production of 7,655 cows with known age at first calving and a total of 27,118 parity records from 301 purebred Blonde d’Aquitaine herds were used to demonstrate the economic benefits of 2 yr of age at first calving. Ages at first calving ranged from 20 to 48 mo, and cows were divided into 5 calving groups, starting with early calving from age 20 to 27 mo up to late calving from age 40 to 48 mo. The information was gathered into 2 data sets, one for only primiparous cows and the second for all cows. The traits analyzed in this study were grouped as functional, linear type, and production traits. Functional traits were calving interval, calving ease, and number of calvings. Skeletal, muscle, and functional appraisal were included as linear type traits. The production traits studied were BW and weaning weight, carcass growth, and conformation of the offspring. The only significant traits found in primiparous cows were late age at first calving, which resulted in heavier BW calves, and early age at first calving, which resulted in calves with greater carcass conformation scores. Age at first calving was found to be significant only in its effect on BW and the number of calvings over a cow’s lifetime, with lighter calves for early age at first calving. Heritability for age at first calving was 0.17. Genetic correlation of age at first calving with direct calving ease was positive (0.27) and that with maternal calving ease was negative (−0.39). Age at first calving showed a negative genetic correlation with lifetime number of calvings (−0.29) and a positive correlation with calving interval (0.14). Correlations with production and type traits were low, except for skeletal development (−0.29). Based on phenotypic and genetic analysis, there is a tendency for early-calving cows to produce a greater lifetime number of calves with less muscle but good carcass growth. Age at first calving affected the number of heifers in the herd, replacement rate, and number of animals slaughtered each year. Shortening the age at first calving from 3 to 2 yr led to a reduction of heifer feeding cost of US$21.24 (17.7€), a reduction of production cost of $26.52 (22.1€), and a profit increase of $25.80 (21.50€) per slaughtered animal per year over lifetime cow production.
  • 16.

    【2hr】Evaluation of nonadditive effects in yearling weight of tropical beef cattle

    包量

    机译 评估热带肉牛一岁体重的非加性效应
    摘要：Nonadditive effects may contribute to genetic variation of complex traits. Their inclusion in genetic evaluation models may therefore improve breeding value estimates and lead to more accurate selection decisions. In this study, we evaluated a systematic series of models accounting for additive, dominance and first-order epistatic interaction (additive by additive, GxG; additive by dominance, GxD; and dominance by dominance, DxD) on body yearling weight (YWT) of 2,550 Tropical Composite (TC) and 2,111 Brahman (BB) cattle in Australia. For both breeds, similar estimates of additive and phenotypic variances and narrow and broad-sense heritability values were obtained across the evaluated models except when GxG effect was considered. In this case, additive variance was slightly lower than that obtained in the models which do not consider this effect. The estimated dominance and epistatic variances from additive and dominance effects (AD) and additive, dominance and epistatic effects models (ADE) were greater than that ADH and ADEH models (as described above plus heterozygosity as a covariate). However, all genetic parameter estimates were associated with a large standard deviation. Averaged across ADH and ADHE models, the magnitude of dominance variance compared to the phenotypic variance of YWT was 14% (BB) and 10% (TC). The magnitude of epistasis compared to the phenotypic variance for BB and TC was 17% and 29%, respectively for GxG; 0.7% and 0% for GxD; and 0% and 0% for DxD. The inclusion of nonadditive effects slightly improves the predictive accuracy of breeding values from 0.28 for A to 0.33 for ADHEGxG and from 0.18 for A to 0.23 ADEGxD in BB and TC cattle. Models that included heterozygosity (ADH and ADHE) must be used to estimate nonadditive genetic variance components. A 1 Mb sliding window analysis identified a region on BTA 14 explaining 10.08% and 1.21% of total genetic variance (additive + dominance) of YWT in BB and TC, respectively. Our results suggest that dominance, epistasis, and heterozygosity should be included in models for genetic parameters estimation. To identify the animals with the highest additive genetic value in selection decisions, only the additive effect should be used in evaluation models.
  • 17.

    【2hr】Evidence of negative relationship between female fertility and feed efficiency in Nellore cattle

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    机译 内洛尔牛的雌性繁殖力与饲料效率之间负相关的证据
    摘要：The objective of this study was to evaluate phenotypic and genetic relationships between fertility traits and feed efficiency in male and female Nellore cattle. Data from 320 females born between 2004 and 2011 were used for phenotypic evaluation. These animals were evaluated for postweaning residual feed intake (RFI) and classified as negative (RFI < 0, mean = −0.294 ± 0.017 kg DM/d) or positive RFI (RFI > 0, mean = 0.305 ± 0.0189 kg DM/d). Of these, 118 prepuberal heifers were submitted to ultrasonography of the uterus and ovaries for monitoring the presence (or absence) of a corpus luteum and for the measurement of endometrial thickness. The following fertility traits were evaluated in all females: age at first calving, days to calving, first calving interval, calving success, stayability, and longevity. The variance components were estimated by the average information restricted maximum likelihood method under an animal model in 5-trait analysis of backfat and rump fat thickness, scrotal circumference, days to calving, and RFI. The total number of animals with records was 6,718, including 927 males with records of scrotal circumference and RFI and 264 females with records of days to calving and RFI. Negative RFI females consumed 12.5% less DM daily than positive RFI females and had a lower rump fat thickness when evaluated postweaning. Among the fertility traits studied, only first calving interval differed (P = 0.0858) between RFI classes, with the interval of negative RFI females being 45 d shorter than that of positive RFI animals. The heritability estimates were 0.29, 0.34, 0.50, 0.12, and 0.16 for backfat and rump fat thickness, scrotal circumference, days to calving, and RFI, respectively. The genetic correlations between RFI and the other traits studied were unfavorable for selection and were of moderate magnitude with backfat thickness, rump fat thickness, and days to calving (0.53, 0.37, and −0.49, respectively) and close to zero with scrotal circumference (0.07). Scrotal circumference (0.17 and 0.15) and days to calving (−0.10 and −0.22) were weakly and favorably correlated with backfat and rump fat thickness. There is evidence of moderate genetic antagonism between female fertility and feed efficiency, but with no evidence of a genetic correlation between male fertility and feed efficiency. There is also evidence of low genetic synergism between fat thickness and fertility.
  • 18.

    【2hr】Animal production and soil characteristics from integrated crop-livestock systems: toward sustainable intensification

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    机译 作物－畜牧综合系统的动物生产和土壤特征：向可持续集约化发展
    摘要：
  • 19.

    【2hr】Conceptual framework for investigating causal effects from observational data in livestock

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    机译 从牲畜观察数据调查因果关系的概念框架
    摘要：Understanding causal mechanisms among variables is critical to efficient management of complex biological systems such as animal agriculture production. The increasing availability of data from commercial livestock operations offers unique opportunities for attaining causal insight, despite the inherently observational nature of these data. Causal claims based on observational data are substantiated by recent theoretical and methodological developments in the rapidly evolving field of causal inference. Thus, the objectives of this review are as follows: 1) to introduce a unifying conceptual framework for investigating causal effects from observational data in livestock, 2) to illustrate its implementation in the context of the animal sciences, and 3) to discuss opportunities and challenges associated with this framework. Foundational to the proposed conceptual framework are graphical objects known as directed acyclic graphs (DAGs). As mathematical constructs and practical tools, DAGs encode putative structural mechanisms underlying causal models together with their probabilistic implications. The process of DAG elicitation and causal identification is central to any causal claims based on observational data. We further discuss necessary causal assumptions and associated limitations to causal inference. Last, we provide practical recommendations to facilitate implementation of causal inference from observational data in the context of the animal sciences.
  • 20.

    【2hr】Effects of reductive acetogenic bacteria and lauric acid on in vivo ruminal fermentation, microbial populations, and methane mitigation in Hanwoo steers in South Korea

    包量

    机译 还原性产乙酸细菌和月桂酸对韩国Hanwoo ers牛体内瘤胃发酵，微生物种群和甲烷缓解的影响
    摘要：
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