Applied Animal Science最新文献_第7页

Evaluating and improving the pasture factor based on herbage allowance and nutritive value to estimate the daily herbage intake of stockers grazing bermudagrass 基于草料补给量和营养价值评价和改进放牧因子，估算放牧者日采食量

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.15232/aas.2024-02633

P. Woli , C.R. Long , L.O. Tedeschi , F.M. Rouquette Jr

Objective

The critical herbage allowance (^cHA), de- fined as the herbage allowance (HA) level below which DMI becomes limiting, is a key variable defining the pas- ture factor used in a daily gain model (DGM) to estimate the daily DMI of stockers grazing bermudagrass (Cynodon dactylon [L.] Pers.) as constrained by HA and nutritive value. Our objective was to evaluate the DGM containing the ^cHA function using a new, comprehensive database.

Materials and Methods

We evaluated the DGM with its ^cHA function, using the observed and model-predicted ADG values involving 1,032 stocker calves in 33 grazing trials conducted at Overton, Texas. Based on evaluation results, we then modified the ^cHA function by incorporat- ing an enhancement factor (κ). By running the DGM with a potential κ value and evaluating it using the ADG data several times iteratively, we derived the best κ value.

Results and Discussion

Evaluation results showed that the DGM containing the original ^cHA function con- sistently underpredicted ADG, as the function was too restrictive to DMI. This issue indicated that the ^cHA func- tion needed to be less restrictive. After multiple iterations of DGM running and testing, we derived 0.75 for κ. With the modification of the ^cHA function through the incor- poration of κ (= 0.75), the DGM performance improved significantly. The modeling efficiency increased by about 31%, the modeling error decreased by about 16%, and the estimated DMI increased from 1.9% BW to 2.1% BW for stockers grazing bermudagrass.

Implications and Applications

By incorporating κ into the ^cHA function in the DGM, this study addressed the issue of consistent underprediction of ADG. By in- cluding the improved ^cHA function in an herbage intake prediction system, the DGM users can more accurately explore the effects of various management and environ- mental factors on daily DMI and ADG of stockers grazing bermudagrass.

目的：在日增重模型（DGM）中，放牧人放牧百慕大草（Cynodon dactylon）的日增重模型（DGM）中，临界供草量（cHA）是决定草场因子的关键变量。[Pers.])，受HA和营养价值的限制。我们的目标是使用一个新的、全面的数据库来评估包含cHA函数的DGM。材料与方法利用在德克萨斯州奥弗顿进行的33次放牧试验中1032头牲畜的平均日增重观测值和模型预测值，对DGM及其cHA功能进行了评估。根据评估结果，我们通过加入增强因子（κ）来修改cHA函数。通过运行具有潜在κ值的DGM，并使用ADG数据进行多次迭代评估，得出最佳κ值。结果与讨论评价结果表明，含有原始cHA功能的DGM始终低于ADG，因为该功能对DMI的限制太大。这个问题表明cHA功能需要减少限制。经过多次DGM运行和测试，我们得出κ值为0.75。通过加入κ(= 0.75)对cHA函数进行修饰，DGM性能显著提高。模拟效率提高约31%，模拟误差降低约16%，放牧者放牧时的DMI由1.9% BW提高到2.1% BW。通过将κ纳入DGM中的cHA功能，本研究解决了ADG一致低估的问题。通过在牧草采食量预测系统中引入改进的cHA功能，DGM用户可以更准确地探索各种管理和环境因素对放牧百慕草的日采食量和平均日增重的影响。

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引用次数: 0

Comparison of alternative backgrounding and feedlot system strategies on performance of May-born, Red Angus cross yearling steers in the Nebraska Sandhills 内布拉斯加州沙丘地区5月出生的红安格斯杂交一岁阉牛的不同饲养背景和饲养系统策略的比较

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.15232/aas.2024-02613

Dempster M. Christenson, Jacki A. Musgrave, Rick N. Funston

Objective

Our objective was to examine the physical performance and economic outcomes of differing backgrounding and feedlot systems on May-born yearling steers.

Materials and Methods

Steers weaned in January (n = 392) were blocked by BW and randomly assigned to 1 of 2 backgrounding treatments for 4 mo: given ad libitum meadow hay and 1.81 kg/d of a 33% CP supplement (HI) or allowed to graze dormant subirrigated meadow with 0.45 kg/d supplement (LO). In May, one-half of the steers from each backgrounding treatment were blocked by BW and transported to a feedlot system (S-YRL) before slaughter at 18.5 mo of age. The remaining steers grazed upland range (L-YRL), were transported to a feedlot mid-September, and were slaughtered at 21.5 mo of age. The net return of treatment for each study year was applied to 12 consecutive years of economic conditions.

Results and Discussion

There were no interactions between treatments. Backgrounding period ADG was 0.24 ± 0.03 kg/d greater among HI calves than among LO calves, which led to 31 ± 3.6 kg greater BW after backgrounding and 20 ± 7.7 kg greater BW at slaughter. However, LO calves had $209.46 ± $12.82 per head greater net return. Greater nutritional value in S-YRL steers at an earlier age led to 0.38 ± 0.03 kg/d greater ADG after the backgrounding period and 0.01 ± 0.003 greater G:F. However, L-YRL steers entered the feedlot 4 mo later with 99 ± 7.5 kg greater BW, a tendency for 0.08 ± 0.04 kg/d greater ADG in the feedlot, 39 ± 9.7 kg greater BW at slaughter, and $148.86 ± $38.72 per head greater net return. Marbling score, LM area, and YG were greater or tended to be greater for L-YRL steers, which led to greater empty body fat.

Implications and Applications

Backgrounding with greater inputs decreased net return, whereas extended grazing followed by a relatively shorter feedlot period decreased feed costs and increased net return.

我们的目的是研究不同背景和饲养场系统对五月出生的一岁阉牛的生理性能和经济结果。材料与方法1月断奶的阉牛（n = 392）以体重为指标，随机分为2种背景处理中的1种，分别饲喂草甸干草和1.81 kg/d 33%粗蛋白质（HI），或饲喂0.45 kg/d的休眠草甸。5月，在18.5月龄的屠宰前，每个背景处理中有一半的阉牛被BW阻塞并运送到饲养场系统（S-YRL）。其余的阉牛在高地牧场（L-YRL）放牧，9月中旬运到饲养场，在21.5月龄时屠宰。每个研究年的治疗净收益适用于连续12年的经济条件。结果与讨论治疗间无相互作用。背景饲喂期高体重犊牛的平均日增重比低体重犊牛高0.24±0.03 kg/d，导致背景饲喂后体重增加31±3.6 kg，屠宰时体重增加20±7.7 kg。然而，LO犊牛的净收益每头高出209.46±12.82美元。早期营养价值越高，背景期后平均日增重增加0.38±0.03 kg/d， G:F增加0.01±0.003 kg/d。然而，L-YRL阉牛进入饲养场4个月后，体重增加99±7.5公斤，在饲养场的平均日增重增加0.08±0.04公斤/天，屠宰时体重增加39±9.7公斤，每头净收益增加148.86±38.72美元。L-YRL的大理石纹评分、LM面积和YG更大或倾向于更大，这导致更多的空体脂肪。影响和应用背景：增加投入会降低净收益，而延长放牧时间后相对较短的饲养场周期会降低饲料成本并增加净收益。

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IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.1016/S2590-2865(25)00024-2

引用次数: 0

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IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.1016/S2590-2865(25)00029-1

引用次数: 0

Evaluation of Saccharomyces cerevisiae fermentation product on the prevention of digital dermatitis using an experimental infection model in cattle 用实验感染模型评价酿酒酵母发酵产物对牛数字性皮炎的预防作用

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.15232/aas.2024-02567

K. Anklam , M. Aviles , J. Buettner , S. Henschel , R. Sanchez , S. Ordaz , I. Yoon , J. Wheeler , G. Dawson , D. Doepfer

Objective

The objective of this research was to evaluate the efficacy of a feed supplement, Saccharomyces cerevisiae fermentation product (SCFP, NutriTek, Diamond V, Cedar Rapids, IA), on the prevention of digital dermatitis (DD) lesions in Holstein Friesian steers. For this research, an experimental infection model was used to reliably induce DD lesions in cattle.

Materials and Methods

A blind completely randomized study was conducted using a digital dermatitis infection model. Following 7 d of hydropic skin maceration in a wrap, the hind feet of 49 Holstein Friesian steers (24 control and 25 SCFP) were inoculated with bovine DD lesion homogenate and remained wrapped until clinical signs of DD were observed or until the protocol endpoint. Pellets containing SCFP (12 g/d NutriTek) or control supplements were mixed in the steers’ respective daily total mixed ration and fed throughout the duration of the study.

Results and Discussion

Seven days after inoculation, all 49 steers developed an M1 (early focal bacterial keratolysis of the epidermis) or M2 (ulcerated/active) lesion on at least 1 hind foot. Treponeme species were detected by polymerase chain reaction, and invasive spirochetes were observed by histology in skin biopsies of the experimentally induced DD lesions. In this DD induction model, the relative risk of steers to develop M2 lesions in the control group was 1.53 (1.09–2.15, 95% CI) times greater than the SCFP group, although SCFP supplementation did not significantly affect the size of the M2 lesions. The multivariable regression analysis, adjusted for risk factors, confirmed that the control steers were significantly more likely to develop M2 lesions than the SCFP steers.

Implications and Applications

The DD experimental infection model used in the present study is useful for testing additional intervention strategies in cattle. The protective effect of SCFP against developing experimentally induced M2 DD lesions suggests that SCFP can be considered as a nutritional intervention to mitigate the risk of DD infection. Additional research is warranted to evaluate the potential mode of action to support the use of SCFP supplementation in the prevention of the development and transmission of DD lesions in cattle under field conditions.

目的本研究的目的是评估一种饲料添加剂——酿酒酵母发酵产物（SCFP, NutriTek, Diamond V, Cedar Rapids， IA）对荷斯坦弗里西亚牛数字性皮炎（DD）病变的预防效果。在本研究中，采用实验感染模型可靠地诱导牛DD病变。材料与方法采用数字皮炎感染模型进行全随机盲法研究。在包裹7天后，将49头荷斯坦弗里西亚阉牛的后脚（24只对照和25只SCFP）接种牛DD病变匀浆，并保持包裹，直到观察到DD的临床症状或直到方案结束。在整个研究期间，将含有SCFP （12 g/d NutriTek）或对照补充剂的颗粒混合在犊牛的每日总混合日粮中。结果和讨论接种后7天，所有49头牛在至少1只后脚出现M1（表皮早期局灶性细菌性角化）或M2（溃疡/活动性）病变。采用聚合酶链反应检测密螺旋体种类，并在实验诱导的DD病变皮肤活检中观察到侵袭性螺旋体。在这个DD诱导模型中，对照组小鼠发生M2病变的相对风险是SCFP组的1.53倍（1.09-2.15,95% CI），尽管补充SCFP对M2病变的大小没有显著影响。多变量回归分析，调整了危险因素，证实对照者比SCFP者更容易发生M2病变。意义和应用本研究中使用的DD实验感染模型可用于测试牛的其他干预策略。SCFP对实验诱导的M2 DD病变的保护作用表明，SCFP可以被认为是一种营养干预，以减轻DD感染的风险。需要进一步的研究来评估潜在的作用模式，以支持使用SCFP补充剂来预防牛在野外条件下DD病变的发生和传播。

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引用次数: 0

Evaluating the effects of acidosis and bacterial inoculum concentrations on the development of liver abscesses in beef × dairy steers 评价酸中毒和细菌接种浓度对牛乳阉牛肝脓肿发展的影响

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.15232/aas.2024-02641

Kallie D. Childress , Kristin E. Hales , T.G. Nagaraja , Ty E. Lawrence , Raghavendra G. Amachawadi , Nicole C. Burdick Sanchez , Aubrey C. Thompson-Smith , Ashlee N. Hanratty , Colten W. Dornbach , Mina Abbasi , Xiaorong Shi , Maddie S. Grant , Michael L. Galyean , Paul R. Broadway

Objective

We evaluated the association of diet type, ruminal acidosis bout frequency, and intraruminal bacterial inoculum concentration on liver abscess (LA) development in steers.

Materials and Methods

Beef × dairy steers (n = 40, initial BW = 107 ± 11 kg) were assigned randomly to 1 of 5 treatments that included intraruminal inoculation of either a high dose (HD; 100 mL of 1 × 10⁸ and 100 mL of 1 × 10⁹ cfu per steer) or a low dose (LD; 100 mL of 1 × 10⁶ and 100 mL of 1 × 10⁷ cfu per steer) of Fusobacterium necrophorum ssp. necrophorum and Salmonella enterica serovar Lubbock, respectively. Treatments included the following: NCON = high-forage diet with no bacterial inoculation; CON+HD = high-forage diet with a single HD inoculation; 2AD+HD = 2 acidotic diet cycles with a single HD inoculation; 4AD+3LD = 4 acidotic diet cycles with a series of 3 LD inoculations; and 4AD+HD = 4 acidotic diet cycles with a single HD inoculation. Steers were slaughtered 21 d after the last bacterial inoculation. Animal was the experimental unit. Continuous data were analyzed using mixed models, and categorical data were analyzed as binomial proportions with treatment, time, and their interactions as the fixed effects.

Results and Discussion

Incidence of LA were 0%, 37.5%, 37.5%, 50%, and 12.5% for NCON, CON+HD, 2AD+HD, 4AD+3LD, and 4AD+HD, respectively, but the difference among treatments was not significant. Although no difference was observed in rumenitis among treatments, steers with LA presented rumenitis scores that were 8 percentage points greater than steers without LA. Steers consuming the high-forage diet also were presented with rumenitis. Hematocrit values were greater in NCON, 2AD+HD, and 4AD+HD than CON+HD or 4AD+3 LD. Similarly, neutrophil:lymphocyte ratio differed among treatments, with a greater ratio for CON+HD and 2AD+HD than for NCON, 4AD+3LD, and 4AD+HD.

Implications and Applications

A key finding of this study was that steers fed a high-forage diet given a high dose of F. necrophorum and S. enterica, even in the absence of the acidotic diet, developed LA.

目的探讨饲粮类型、瘤胃酸中毒发作频率和瘤胃内细菌接种浓度与犊牛肝脓肿（LA）发展的关系。材料与方法40头牛×乳牛（n = 40，初始体重= 107±11 kg）随机分为5个处理，其中1个处理包括高剂量(HD；每头牛100毫升1 × 108和100毫升1 × 109 cfu)或低剂量(LD；每头牛100 mL 1 × 106 cfu和100 mL 1 × 107 cfu)。分别为necrophorum和enterica serovar Lubbock。处理包括：NCON =高饲粮，不接种细菌；CON+HD =单次接种HD的高饲粮；2AD+HD = 2个酸中毒饮食周期，单次接种HD；4AD+3LD = 4个酸中毒饲粮周期，连续接种3次LD；4AD+HD = 4个酸中毒饮食周期，单次接种HD。最后一次细菌接种21 d后屠宰。动物为实验单位。连续数据采用混合模型分析，分类数据采用二项比例分析，以治疗、时间及其相互作用为固定效应。NCON、CON+HD、2AD+HD、4AD+3LD、4AD+HD的LA发生率分别为0%、37.5%、37.5%、50%、12.5%，但不同治疗间差异无统计学意义。虽然在不同的治疗中没有观察到瘤胃炎的差异，但LA的阉牛的瘤胃炎评分比没有LA的阉牛高8个百分点。食用高饲料日粮的阉牛也出现了瘤胃炎。NCON、2AD+HD和4AD+HD患者的血细胞比容值高于CON+HD或4AD+3LD。同样，不同治疗组的中性粒细胞：淋巴细胞比率也不同，CON+HD和2AD+HD患者的比例高于NCON、4AD+3LD和4AD+HD。本研究的一个关键发现是，饲喂高饲料饲粮的公牛，即使在没有酸性饲料的情况下，也会被给予高剂量的坏死乳杆菌和肠球菌。

{"title":"Evaluating the effects of acidosis and bacterial inoculum concentrations on the development of liver abscesses in beef × dairy steers","authors":"Kallie D. Childress , Kristin E. Hales , T.G. Nagaraja , Ty E. Lawrence , Raghavendra G. Amachawadi , Nicole C. Burdick Sanchez , Aubrey C. Thompson-Smith , Ashlee N. Hanratty , Colten W. Dornbach , Mina Abbasi , Xiaorong Shi , Maddie S. Grant , Michael L. Galyean , Paul R. Broadway","doi":"10.15232/aas.2024-02641","DOIUrl":"10.15232/aas.2024-02641","url":null,"abstract":"<div><h3>Objective</h3><div>We evaluated the association of diet type, ruminal acidosis bout frequency, and intraruminal bacterial inoculum concentration on liver abscess (LA) development in steers.</div></div><div><h3>Materials and Methods</h3><div>Beef × dairy steers (n = 40, initial BW = 107 ± 11 kg) were assigned randomly to 1 of 5 treatments that included intraruminal inoculation of either a high dose (HD; 100 mL of 1 × 10<sup>8</sup> and 100 mL of 1 × 10<sup>9</sup> cfu per steer) or a low dose (LD; 100 mL of 1 × 10<sup>6</sup> and 100 mL of 1 × 10<sup>7</sup> cfu per steer) of <em>Fusobacterium necrophorum</em> ssp. <em>necrophorum</em> and <em>Salmonella enterica</em> serovar Lubbock, respectively. Treatments included the following: NCON = high-forage diet with no bacterial inoculation; CON+HD = high-forage diet with a single HD inoculation; 2AD+HD = 2 acidotic diet cycles with a single HD inoculation; 4AD+3LD = 4 acidotic diet cycles with a series of 3 LD inoculations; and 4AD+HD = 4 acidotic diet cycles with a single HD inoculation. Steers were slaughtered 21 d after the last bacterial inoculation. Animal was the experimental unit. Continuous data were analyzed using mixed models, and categorical data were analyzed as binomial proportions with treatment, time, and their interactions as the fixed effects.</div></div><div><h3>Results and Discussion</h3><div>Incidence of LA were 0%, 37.5%, 37.5%, 50%, and 12.5% for NCON, CON+HD, 2AD+HD, 4AD+3LD, and 4AD+HD, respectively, but the difference among treatments was not significant. Although no difference was observed in rumenitis among treatments, steers with LA presented rumenitis scores that were 8 percentage points greater than steers without LA. Steers consuming the high-forage diet also were presented with rumenitis. Hematocrit values were greater in NCON, 2AD+HD, and 4AD+HD than CON+HD or 4AD+3 LD. Similarly, neutrophil:lymphocyte ratio differed among treatments, with a greater ratio for CON+HD and 2AD+HD than for NCON, 4AD+3LD, and 4AD+HD.</div></div><div><h3>Implications and Applications</h3><div>A key finding of this study was that steers fed a high-forage diet given a high dose of <em>F. necrophorum</em> and <em>S. enterica</em>, even in the absence of the acidotic diet, developed LA.</div></div>","PeriodicalId":8519,"journal":{"name":"Applied Animal Science","volume":"41 2","pages":"Pages 93-103"},"PeriodicalIF":1.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Review: Sustainable phosphorus use in the United States beef cow-calf industry—Requirements, forage, soil, and water content, supplementation, and nutritional recommendations for producers 综述：美国肉牛-小牛工业中磷的可持续利用——要求、饲料、土壤和水分含量、补充和对生产者的营养建议

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.15232/aas.2024-02643

J.M. Warner , G.E. Fike , A.G. Schwartz , J.W. Waggoner , S.K. Johnson

Purpose

The objective is to explain the current understanding of the biological importance of P to beef cattle congruent with current established requirements as well as describe the current management toward P supplementation, nutritional recommendations, quantify forage, soil, and water mineral concentrations, and identify existing knowledge gaps specific for improving sustainable use of the mineral in United States cow-calf production.

Sources

Peer-reviewed literature, abstracts, experiment station progress reports, technical bulletins, and reports were the primary sources of information reviewed.

Synthesis

Phosphorus is essential for beef cattle productivity and health as well as a potential water contaminant. Although efforts have been made in recent years to improve our understanding of requirements for growing and finishing beef cattle, relatively little work has been done focused on the cow-calf segment of the industry. Because grazing beef cattle frequently use surface water sources, producers play a critical role in minimizing P introduction to waters. Soil and forage P levels and responses to supplementation vary widely and studies including both animal and agronomic components of P utilization are very limited. Concurrently, data directly evaluating the effect of specific best management practices for improving sustainable P use within cow-calf production systems on surface water quality are few and would be beneficial for industry guidance and producer adoption.

Conclusions and Applications

Long-term cow-calf studies reporting intake and production outcomes that also include soil and forage P levels are needed for developing industry benchmarks and accurate supplementation recommendations. Best management practices implemented holistically are key for minimizing the industry’s use of supplemental P while optimizing animal health and production, particularly in areas where public water quality is of concern.

目的：目的是解释目前对磷对肉牛的生物学重要性的理解，符合目前既定的要求，并描述目前对磷补充的管理，营养建议，量化饲料，土壤和水中矿物质浓度，并确定现有的知识差距，具体到改善美国小牛生产中矿物质的可持续利用。来源同行评议的文献、摘要、实验站进展报告、技术公告和报告是所审查信息的主要来源。磷对肉牛的生产和健康至关重要，也是一种潜在的水污染物。尽管近年来已经做出了努力，以提高我们对肉牛生长和育肥要求的理解，但在该行业的牛犊牛部分所做的工作相对较少。由于放牧肉牛经常使用地表水，因此生产者在尽量减少向水体引入磷方面发挥着关键作用。土壤和饲料磷水平及其对磷补充的响应差异很大，包括动物和农艺成分的磷利用研究非常有限。同时，直接评价具体最佳管理做法对改善牛-小牛生产系统内可持续磷利用对地表水质量影响的数据很少，这将有利于行业指导和生产者采用。结论和应用报告摄入和生产结果的长期犊牛研究，包括土壤和饲料磷水平，需要制定行业基准和准确的补充建议。全面实施最佳管理实践是最大限度地减少行业补充磷使用，同时优化动物健康和生产的关键，特别是在公共水质受关注的地区。

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引用次数: 0

Review: History of chromium in animal nutrition in the United States 回顾：美国动物营养中铬的历史

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-03-24 DOI: 10.15232/aas.2024-02653

J.W. Spears

Purpose

The purpose of this paper is to review animal research studies with chromium (Cr) sources that are permitted or approved by the US Food and Drug Administration (FDA).

Sources

Research in peer-reviewed journals was the source of information reviewed.

Synthesis

Chromium tripicolinate (Chromax) and chromium propionate (KemTRACE Cr) are permitted by FDA for supplementation to swine diets at a level up to 0.20 mg Cr/kg diet. Chromium propionate (CrProp) is permitted by FDA for supplementation to cattle diets at a level up to 0.50 mg Cr/kg diet, and is approved for supplementation to adult horses at a level of 4 mg Cr/d, and broiler and turkey diets at a level not to exceed 0.20 mg Cr/kg diet. Chromium supplementation in swine has increased litter size in sows. In lactating dairy cows, CrProp supplementation has increased milk production and reproductive performance, and increased ADG and hot carcass wt in finishing steers. Improved gain and feed efficiency have been reported in broilers and turkeys supplemented with CrProp. In adult horses, CrProp supplementation increased insulin sensitivity following oral or i.v. carbohydrate administration.

Conclusions and Applications

Studies in lactating dairy cows, finishing steers, broilers, and turkeys have indicated that CrProp supplementation can improve performance. Supplementation of Cr picolinate (CrPic) has increased litter size in sows in several studies. Animal responses to Cr supplementation have been variable and research is needed to determine factors that affect responses to Cr supplementation. Chromium propionate may be beneficial in preventing insulin resistance or improving insulin sensitivity in insulin-resistant horses.

本文的目的是回顾美国食品和药物管理局（FDA）允许或批准的铬（Cr）来源的动物研究。来源同行评议期刊上的研究是被审查的信息来源。三吡啶甲酸铬（Chromax）和丙酸铬（KemTRACE Cr）被FDA允许在猪日粮中添加0.20 mg Cr/kg日粮。FDA允许丙酸铬（CrProp）在牛日粮中添加0.50 mg Cr/kg日粮，并批准在成年马日粮中添加4 mg Cr/d，在肉鸡和火鸡日粮中添加不超过0.20 mg Cr/kg日粮。在猪中添加铬可以增加母猪产仔数。在泌乳奶牛中，添加CrProp可提高产奶量和繁殖性能，提高肥育阉牛的平均日增重和热胴体重。据报道，在肉鸡和火鸡中添加CrProp可提高增重和饲料效率。在成年马中，口服或静脉注射碳水化合物后，补充CrProp增加了胰岛素敏感性。对泌乳奶牛、育肥牛、肉鸡和火鸡的研究表明，添加CrProp可以提高生产性能。在一些研究中，添加吡啶甲酸铬（CrPic）增加了母猪的产仔数。动物对补充铬的反应是不同的，需要研究确定影响对补充铬反应的因素。丙酸铬可能有助于预防胰岛素抵抗或改善胰岛素敏感性。

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引用次数: 0

Targeted durations of tylosin phosphate on incidence and severity of liver abscesses in feedlot cattle* 磷酸泰络素对饲养场牛肝脓肿发生率和严重程度的靶向持续时间*

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-02-01 DOI: 10.15232/aas.2024-02574

L.F.B.B. Feitoza , A.N. Baker , R.L. Thorn , L.S. Monteiro , F. Nasiu , T.G. Nagaraja , Q. Kang , J.S. Drouillard

Objective

Our objective was to assess the effects of feeding tylosin phosphate at 60 mg∙steer⁻¹∙d⁻¹ for the first 30 or 60 d of the finishing phase on the incidence and severity of liver abscesses, performance, and carcass characteristics in feedlot steers.

Materials and Methods

Steers (n = 462) were randomly assigned to 1 of 3 treatments: no tylosin phosphate (control) or tylosin phosphate, administered in the feed as a type B medicated premix supplement, to provide 60 mg∙steer⁻¹∙d⁻¹ for the first 30 d (T-30) or 60 d (T-60) of the finishing phase (steers were fed the control diet for the remaining days of the finishing phase). Steers were housed in pens with 7 steers per pen and 22 pens per treatment. Cattle BW were recorded at 30-d intervals, and final BW was recorded on d 161 on feed. Steers were processed at a commercial abattoir, and incidence and severity of liver abscesses and carcass characteristics were recorded.

Results and Discussion

Incidence of abscessed livers was not affected by targeted durations of tylosin phosphate administration. However, there was a trend for severe abscesses to happen less in T-30 and T-60 than in the control, possibly because of inclusion of tylosin phosphate during the diet transition phase when cattle are likely to experience ruminal acidosis. Steers that received tylosin phosphate had greater BW on d 30 or 60 compared with the control. Steer performance and carcass characteristics were not affected by treatments.

Implications and Applications

Administration of tylosin phosphate at 60 mg per animal daily for the first 30 or 60 d of the finishing phase had no effect on the incidence of abscessed livers, although there was a trend for the reduction in severe abscesses in feedlot steers.

我们的目的是评估在肥育期的前30或60天以60 mg∙steer - 1∙d - 1饲喂磷酸泰洛菌素对饲养场阉牛肝脓肿的发生率和严重程度、生产性能和胴体特征的影响。材料与方法将462头阉牛随机分为不添加磷酸泰乐菌素（对照）和作为B型药物预混料添加的磷酸泰乐菌素3种处理中的1种，在肥育期的前30天（T-30）或60天（T-60）提供60 mg∙阉牛−1∙d−1（肥育期的其余天饲喂对照饲粮）。阉牛被饲养在围栏中，每围栏7头，每次处理22头。每隔30 d记录一次牛的体重，在饲喂第161 d记录最终体重。在商业屠宰场对阉牛进行加工，并记录肝脓肿的发生率和严重程度以及胴体特征。结果与讨论肝脓肿发生率不受磷酸泰络菌素给药时间的影响。然而，与对照组相比，T-30和T-60组出现严重脓肿的趋势更少，这可能是因为在饲粮过渡阶段，牛可能出现瘤胃酸中毒。与对照组相比，接受磷酸泰菌素治疗的奶牛在第30天或第60天的体重更高。阉畜性能和胴体特性不受处理影响。意义和应用育肥期的前30或60天，每头动物每天给予60mg磷酸泰洛菌素对肝脏脓肿的发生率没有影响，尽管在饲养场的阉牛中有严重脓肿减少的趋势。

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引用次数: 0

Myosin heavy chain, myogenic regulatory factors, and steroid hormone receptor responses in serially slaughtered implanted or nonimplanted beef steers 连续屠宰植入或未植入肉牛的肌球蛋白重链、肌生成调节因子和类固醇激素受体反应

IF 1.4 Q3 AGRICULTURE, DAIRY & ANIMAL SCIENCE

Applied Animal Science

Pub Date : 2025-02-01 DOI: 10.15232/aas.2024-02579

K.R. Wesley , L.K. Fuerniss , J.T. Jobe , J.P. Hutcheson , W.T. Nichols , T.J. Kirkpatrick , S.L. Pillmore , K.B. Cooper , B.J. Johnson , T.E. Lawrence

Objective

The objective of this study was to quantify changes in beef steers in myosin-heavy-chain fiber type, myogenic regulatory factors, and steroid hormone receptors over time and in response to implantation in the longissimus dorsi (LD), semitendinosus (ST), and diaphragm (D) muscles.

Materials and Methods

Eighty beef steers were paired based on estimated final BW, and individuals received no implant (CON) or Revalor-XS (Merck Animal Health) administered at d 0 and 190 (IMP). Four pairs of steers were randomly assigned to slaughter group at 42-d intervals from d 0 to 378. At slaughter, samples were collected from the LD, ST, and D muscles of each animal for immunohistochemical analysis.

Results and Discussion

Proportions of cross-sectional area (CSA) occupied by each myosin-heavy-chain type were not different between implant treatments. Increased days on feed led to increased CSA in all muscles. Total nuclei density tended to be greater in CON steers. Myogenic regulatory factors expressed as a proportion of total nuclei led to no difference due to implant treatment in all variables, except a tendency for increased proportion of myonuclei in the ST of IMP steers. Day influenced all variables in the LD with positive quadratic effects on proportion of myonuclei and MYF5-positive nuclei. In the ST, day affected proportion of myonuclei and PAX7- and MYF5/ PAX7-dual-positive nuclei. All myogenic factors were affected by day in the D. Steroid receptor expression was unaffected by implant status regardless of muscle. Day tended to affect steroid receptor variables in the LD, ST, and D, with varying trends by muscle and variable.

Implications and Applications

Implant treatment did not alter the proportion of muscle fiber types, myogenic outcomes relative to total nuclei, or steroid hormone receptors. However, implant administration increased overall CSA by 9% to 16%, suggesting enhanced muscle growth without affecting muscle composition or regulatory mechanisms.

本研究的目的是量化牛在背最长肌（LD）、半腱肌（ST）和横膈膜(D)肌肉植入后，肌球蛋白重链纤维类型、肌生成调节因子和类固醇激素受体随时间的变化。材料和方法根据估计的最终体重对80头肉牛进行配对，个体未接受植入物（CON）或在0和190 （IMP）时给予revor - xs（默克动物保健公司）。4对阉牛从第0 ~ 378天每隔42 d随机分为屠宰组。屠宰时，从每只动物的LD、ST和D肌肉中采集样本进行免疫组织化学分析。结果与讨论各肌球蛋白重链型所占的横截面积（CSA）比例在不同种植体处理间无显著差异。饲粮天数的增加导致所有肌肉CSA的增加。总核密度在对照组中更大。肌生成调节因子在总细胞核中所占比例的表达在所有变量中都没有差异，除了在IMP小鼠的ST中肌核比例有增加的趋势。日影响LD的所有变量，对my核和myf5阳性核的比例有正二次效应。在ST中，日晒影响了肌核和PAX7-和MYF5/ PAX7双阳性核的比例。类固醇受体的表达不受植入状态的影响，与肌肉无关。Day倾向于影响LD、ST和D的类固醇受体变量，随肌肉和变量的变化趋势不同。植物治疗没有改变肌纤维类型的比例、相对于总核的成肌结果或类固醇激素受体。然而，植入物使总体CSA增加了9%至16%，这表明在不影响肌肉成分或调节机制的情况下，肌肉生长得到了促进。

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