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Confirmed bacteriological diagnosis and cure of nonsevere gram-positive clinical mastitis cases enrolled in a randomized clinical trial based on results of on-farm culture 根据农场培养结果对随机临床试验中的非严重革兰氏阳性临床乳腺炎病例进行确诊和治愈

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2024-0560

Q.K. Kolar , S.M. Godden , R.J. Erskine , P.L. Ruegg

Our objectives were to describe the confirmed bacteriological diagnosis of mastitis pathogens cultured from cases of nonsevere clinical mastitis (CM) identified as gram-positive (GP) using on-farm culture and to compare differences in bacteriological cure (BC) based on antimicrobial (AM) therapy. Cows that developed nonsevere CM in a single quarter were enrolled in a randomized clinical trial based on microbial growth on GP selective agars. Cows were randomly assigned to receive a once-daily intramammary treatment: 3 d hetacillin (n = 69), 3 d ceftiofur (n = 69), 8 d ceftiofur (n = 70), or to a nontreated group (n = 32). Etiologies were confirmed with MALDI-TOF using frozen duplicate milk samples. The crude proportion of BC was determined using milk samples collected at 14, 21, and 28 d after enrollment for cases caused by streptococci, NAS, Streptococcus-like organisms (consisting of Enterococcus and Lactococcus; SLO), and Staphylococcus aureus. Multivariable models were used to determine the effect of AM treatment on BC cure at d 21 for a subset of cases that had complete data for all covariates (n = 88). Growth on GP agar resulted in enrollment of 240 cases with confirmed etiologies distributed as Streptococcus spp. (21.7%; n = 52), Lactococcus spp. (19.2%; n = 46), NAS (16.3%; n = 39), Staph. aureus (6.3%; n = 16), Enterococcus spp. (5.0%; n = 12), and others (10%; n = 24). Thirty-five (14.5%) duplicate milk samples collected from enrolled cows had no significant growth in the laboratory and 16 (6.7%) were contaminated. Among sampling dates, combined crude BC for cases caused by target pathogens ranged from 68% to 71%. Crude BC ranged from 58% to 73% for the small group of nontreated cases (n = 12) and 69% to 71% for the combined group of cases that received intramammary AM (n = 113). Among all groups and all follow-up dates, crude BC was least for cases caused by Staph. aureus (ranging from 33% to 43%), followed by cases caused by SLO (58%–67%), NAS (79%–80%), and Streptococcus spp. (81%–91%). The proportion of BC at 21 d (LSM ± SE) did not vary between all cases that received AM (0.77 ± 0.06) and cases in the nontreated group (0.73 ± 0.16). The odds of BC at 21 d was about 5× greater for cases that occurred in primiparous as compared with multiparous cows and decreased 1.3-fold for each 1 log unit increase in SCC before the case. While this study does not have sufficient power to detect small differences in BC among pathogen groups or treatments, our results demonstrate that CM is caused by a wide diversity of GP bacteria with varying ranges of BC. These results provide justification for inclusion of negative control groups in future studies and confirm that important characteristics such as parity and history of subclinical mastitis influence the probability of BC.

:我们的目标是描述从非重症临床乳腺炎（CM）病例中培养出的细菌学确诊病原体，这些病原体通过农场培养被鉴定为革兰氏阳性（GP），并比较基于抗菌药（AM）疗法的细菌学治愈（BC）差异。根据微生物在 GP 选择性琼脂上的生长情况，将在一个季度内出现非严重 CM 的奶牛纳入随机临床试验。奶牛被随机分配接受每天一次的乳房内治疗：3d hetacillin（n = 69）、3d ceftiofur（n = 69）、8d ceftiofur（n = 70）或未接受治疗组（n = 32）。使用冷冻的重复牛奶样本通过 MALDI-TOF 确认病因。利用入组后 14、21 和 28 天采集的牛奶样本，确定由链球菌、非金黄色葡萄球菌 (NAS)、类链球菌（由肠球菌和乳球菌组成；SLO）和金黄色葡萄球菌引起的 BC 病例的粗比例。对于所有协变量数据完整的病例子集（n = 88），采用多变量模型确定 AM 治疗对 BC 第 21 天治愈的影响。在 GP 琼脂上生长的 240 个病例确认了病因，病因分布为链球菌（21.7%；n = 52）、乳杆菌（19.2%；n = 46）、NAS（16.3%；n = 39）、金黄色葡萄球菌（6.3%；n = 16）、肠杆菌（5.0%；n = 12）和其他（10%；n = 24）。从登记奶牛身上采集的 35 份（14.5%）重复牛奶样本在实验室中没有明显生长，而 16 份（6.7%）受到污染。在不同的采样日期，由目标病原体引起的病例的综合粗 BC 为 68% 至 71%。未接受治疗的一小群病例（12 例）的粗 BC 为 58% 至 73%，接受 IMM AM 治疗的病例（113 例）的粗 BC 为 69% 至 71%。在所有组别和所有随访日期中，由金黄色葡萄球菌引起的病例的粗 BC 最低（33% 至 43%），其次是由 SLO（58% 至 67%）、NAS（79% 至 80%）和链球菌（81% 至 91%）引起的病例。所有接受AM治疗的病例（0.77 ± 0.06）和未接受AM治疗组的病例（0.73 ± 0.16）在21天时出现BC的比例（LSM ± SE）没有差异。与多胎奶牛相比，初产奶牛在21天时发生BC的几率约为多胎奶牛的5倍，病例发生前SCC每增加1个对数单位，BC几率下降1.3倍。虽然本研究没有足够的能力检测病原体组或治疗方法之间 BC 的微小差异，但我们的结果表明，CM 是由多种 GP 细菌引起的，其 BC 范围各不相同。这些结果为在今后的研究中纳入阴性对照组提供了理由，并证实了一些重要特征，如

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Mammary epithelial cell exfoliation increases as milk yield declines, lactation progresses, and parity increases 随着产奶量下降、泌乳期延长和胎次增加，乳腺上皮细胞脱落增加

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2023-0534

H.H. Webster, A.J. Lengi, B.A. Corl

Milk yield (MY) naturally declines after peak lactation. One approach to improving production is to increase lactation persistency, or the length of time a cow maintains lactation. To do so, cows must maintain functional secretory mammary epithelial cells (MEC), which synthesize milk. Some viable MEC are exfoliated from the udder into milk. The objective of this experiment was to identify the magnitude and direction of association between exfoliated MEC and MY, days in milk (DIM), and parity. Our hypothesis was that MY and the quantity of exfoliated MEC were negatively correlated. Therefore, milk from low-yielding, late-lactation, and primiparous cows would contain more MEC. Thirty-six multiparous and 12 primiparous Holstein cows were sampled once during lactation. Flow cytometry was used to identify hematopoietic cells and MEC in milk using an antibody specific for cluster of differentiation-45 (CD45) and an antibody against butyrophilin 1A1 (BTN), respectively. Nucleated cells were stained with Hoechst dye, and propidium iodide was used to identify dead cells. For statistical analysis, we analyzed the effect of parity, MY, and DIM, and DIM² on the number and concentration of both total and live exfoliated MEC. Primiparous cows exfoliated fewer MEC and had a lower concentration of MEC in milk than multiparous cows regardless of lactation stage. This could reflect continued mammary growth in first lactation. Cows shed an average of 9.80 × 10⁷ ± 6.90⁷ MEC (LSM ± SEM) with a concentration of 4,582 ± 3,574 cells/mL in one milking. Milk yield was inversely related to concentration of both total and live MEC in milk. Similarly, cows in late lactation, which is associated with MY decline, exfoliated a greater number of MEC into milk. Primiparous cows had a lower MY and shed fewer total and live MEC in this study. The relationship of MY and DIM with MEC losses in milk may also contribute to declining MEC number in the mammary gland found in postpeak lactation. Understanding MEC exfoliation regulation could help develop husbandry practices that improve secretory cell retention in the mammary gland and increase lactation persistency.

泌乳高峰过后，牛奶产量（MY）会自然下降。提高产量的方法之一是提高泌乳持续率，即奶牛维持泌乳的时间。为此，奶牛必须保持功能性分泌型乳腺上皮细胞（MEC），它能合成牛奶。一些有活力的乳腺上皮细胞会从乳房中脱落变成乳汁。本实验的目的是确定脱落的乳腺上皮细胞与MY、产奶天数（DIM）和胎次之间的关联程度和方向。我们的假设是，MY 与脱落 MEC 的数量呈负相关。因此，低产、晚泌乳和初产奶牛的牛奶中会含有更多的脱落MEC。在泌乳期对 36 头多产荷斯坦奶牛和 12 头初产荷斯坦奶牛采样一次。采用流式细胞术分别用特异性分化簇-45（CD45）抗体和丁淀粉样蛋白 1A1 (BTN) 抗体鉴定牛奶中的造血细胞和 MEC。有核细胞用 Hoechst 染料染色，死细胞用碘化丙啶染色。为了进行统计分析，我们分析了奇偶性、MY、DIM 和 DIM2 对总脱落 MEC 和活 MEC 的数量和浓度的影响。与多胎奶牛相比，无论泌乳阶段如何，初产奶牛脱落的 MEC 数量较少，牛奶中 MEC 的浓度较低。这可能反映了第一泌乳期乳腺的持续增长。奶牛在一次挤奶中平均脱落 9.80 × 107 ± 6.907 个MEC（LSM ± SEM），浓度为 4,582 ± 3,574 cells/mL。产奶量与牛奶中的总活细胞和活细胞浓度成反比。同样，泌乳后期的奶牛（与MY下降有关）在牛奶中脱落的MEC数量较多。在本研究中，初产奶牛的MY较低，脱落的总MEC和活MEC较少。MY和DIM与牛奶中MEC损失的关系也可能导致泌乳后期乳腺中MEC数量的下降。了解 MEC 的脱落调节有助于制定饲养方法，改善乳腺中分泌细胞的保留，提高泌乳持续率。

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Fast and reliable method for analysis of derivatized plasma amino acids by liquid chromatography-single quadrupole-mass spectrometry 利用液相色谱-单四极杆质谱法分析衍生化血浆氨基酸的快速可靠方法

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2024-0546

August Hoppmann, Sebastian I. Arriola Apelo

<div><div>The pool of free, genetically encoded AA in plasma plays an essential role not only as substrate for every protein synthesized in the body but also as signaling molecules that regulate a wide range of physiological processes. Here we present a method for the analysis of 19 of the 20 encoded AA (except Cys) in dairy cow plasma. Isolated plasma or standards for the 19 AA were gravimetrically mixed with an internal standard mix consisting of <sup>13</sup>C isotopes of each AA. Plasma proteins were precipitated on acetonitrile and supernatants transferred to glass vials. For precolumn derivatization, plasma supernatants were buffered with sodium borate (pH 9.5–10), and AA were derivatized with 9-fluorenylmethoxycarbonyl (Fmoc) chloride. Analytes were isolated by solid-phase extraction using a strong-anionic ion exchange column and dry eluates were reconstituted in mobile phase consisting of 70% water solution of ammonium formate and 30% acetonitrile. Amino acid derivatives were separated by reverse-phase liquid chromatography over 17.5 min with a C18 column in which acetonitrile increased to 80% over the first 11 min of the method, before returning to initial levels. Electrospray ionization on negative mode was used for most AA, except Arg and Pro, for which positive mode yielded superior results. Single or double (only Lys) derivatives were measured by single quadrupole-mass spectrometry. We hypothesized that precolumn Fmoc derivatization would yield optimal resolution for quantitative analysis of the 19 targeted AA and their respective <sup>13</sup>C internal standards, with limits of quantitation beyond physiological ranges. All 19 AA were detected with minimal background noise. An 11-point standard curve was developed for each AA. Limits of quantitation were beyond concentrations observed in plasma samples of lactating dairy cows, except for Gly where upper curve points had to be removed to maintain linearity, limiting quantitation to the upper range of physiological concentration. After removing the 4 highest concentrations from the Gly standard curve, coefficients of determination were greater than 0.999 for all of the AA. Recovery of spiked AA from plasma samples ranged from 89.9% for Phe to 100.3% for Trp. Instrument repeatability averaged 0.91 and ranged from 0.33 for Val to 2.29 for Arg. Meanwhile, sample preparation method repeatability averaged 2.02 and ranged from 1.14 for Tyr to 3.34 for Arg. Although robust methods have been developed, they depend on either availability of sophisticated instruments, mostly limited to core facilities (i.e., tandem MS methods), long and expensive chromatography without specific internal standards for each AA (i.e., HPLC-ultraviolet and HPLC-fluorescence detector), or unstable derivatization (GC-MS). Here we describe a method with high throughput, stable derivatization, high precision and recovery, and potentially more affordable than most existing methods. This method could help dairy nutrition

血浆中游离的基因编码 AA 池不仅是体内合成每种蛋白质的底物，还是调节各种生理过程的信号分子，起着至关重要的作用。在此，我们介绍一种分析奶牛血浆中 20 种编码 AA（Cys 除外）中 19 种的方法。将分离的血浆或 19 种 AA 的标准物质与由每种 AA 的 13C 同位素组成的内标混合物进行重量计量混合。血浆蛋白在乙腈中沉淀，上清液转移到玻璃瓶中。柱前衍生时，血浆上清液用硼酸钠（pH 9.5-10）缓冲，AA 用 9-芴甲氧羰酰氯（Fmoc）衍生。使用强阴离子离子交换柱进行固相萃取，分离出分析物，干燥的洗脱液在由 70% 甲酸铵水溶液和 30% 乙腈组成的流动相中重构。氨基酸衍生物采用 C18 反相液相色谱法进行分离，分离时间为 17.5 分钟，在该方法的前 11 分钟内，乙腈的浓度增加到 80%，然后恢复到初始水平。大多数 AA 采用电喷雾负离子模式，但 Arg 和 Pro 除外，正离子模式的结果更佳。单或双衍生物（仅 Lys）采用单四极杆质谱法测定。我们假设，柱前 Fmoc 衍生化将产生最佳分辨率，可对 19 种目标 AA 及其各自的 13C 内标物进行定量分析，定量限可超出生理范围。所有 19 种 AA 均可检测到，背景噪音极小。为每种 AA 都绘制了 11 点标准曲线。除 Gly 外，其他 AA 的定量限均超出了在泌乳奶牛血浆样本中观察到的浓度，为了保持线性，必须去除曲线上部的点，从而将定量限限制在生理浓度的上限范围内。从甘氨酸标准曲线中去除 4 个最高浓度点后，所有 AA 的测定系数均大于 0.999。血浆样品中添加 AA 的回收率从 Phe 的 89.9% 到 Trp 的 100.3% 不等。仪器的重复性平均为 0.91，范围从 Val 的 0.33 到 Arg 的 2.29。同时，样品制备方法的重复性平均为 2.02，从 Tyr 的 1.14 到 Arg 的 3.34 不等。尽管已经开发出了可靠的方法，但这些方法要么依赖于先进的仪器（大多仅限于核心设备）（即串联质谱方法），要么依赖于漫长而昂贵的色谱法（没有针对每种 AA 的特定内标）（即 HPLC-紫外检测器和 HPLC-荧光检测器），要么依赖于不稳定的衍生化（GC-MS）。在此，我们介绍了一种具有高通量、稳定衍生化、高精度和高回收率的方法，而且可能比大多数现有方法更经济实惠。这种方法可以帮助奶牛营养学家在制定日粮策略时考虑血浆 AA 信息，从而降低饲养成本和氮排放量。

{"title":"Fast and reliable method for analysis of derivatized plasma amino acids by liquid chromatography-single quadrupole-mass spectrometry","authors":"August Hoppmann, Sebastian I. Arriola Apelo","doi":"10.3168/jdsc.2024-0546","DOIUrl":"10.3168/jdsc.2024-0546","url":null,"abstract":"<div><div>The pool of free, genetically encoded AA in plasma plays an essential role not only as substrate for every protein synthesized in the body but also as signaling molecules that regulate a wide range of physiological processes. Here we present a method for the analysis of 19 of the 20 encoded AA (except Cys) in dairy cow plasma. Isolated plasma or standards for the 19 AA were gravimetrically mixed with an internal standard mix consisting of <sup>13</sup>C isotopes of each AA. Plasma proteins were precipitated on acetonitrile and supernatants transferred to glass vials. For precolumn derivatization, plasma supernatants were buffered with sodium borate (pH 9.5–10), and AA were derivatized with 9-fluorenylmethoxycarbonyl (Fmoc) chloride. Analytes were isolated by solid-phase extraction using a strong-anionic ion exchange column and dry eluates were reconstituted in mobile phase consisting of 70% water solution of ammonium formate and 30% acetonitrile. Amino acid derivatives were separated by reverse-phase liquid chromatography over 17.5 min with a C18 column in which acetonitrile increased to 80% over the first 11 min of the method, before returning to initial levels. Electrospray ionization on negative mode was used for most AA, except Arg and Pro, for which positive mode yielded superior results. Single or double (only Lys) derivatives were measured by single quadrupole-mass spectrometry. We hypothesized that precolumn Fmoc derivatization would yield optimal resolution for quantitative analysis of the 19 targeted AA and their respective <sup>13</sup>C internal standards, with limits of quantitation beyond physiological ranges. All 19 AA were detected with minimal background noise. An 11-point standard curve was developed for each AA. Limits of quantitation were beyond concentrations observed in plasma samples of lactating dairy cows, except for Gly where upper curve points had to be removed to maintain linearity, limiting quantitation to the upper range of physiological concentration. After removing the 4 highest concentrations from the Gly standard curve, coefficients of determination were greater than 0.999 for all of the AA. Recovery of spiked AA from plasma samples ranged from 89.9% for Phe to 100.3% for Trp. Instrument repeatability averaged 0.91 and ranged from 0.33 for Val to 2.29 for Arg. Meanwhile, sample preparation method repeatability averaged 2.02 and ranged from 1.14 for Tyr to 3.34 for Arg. Although robust methods have been developed, they depend on either availability of sophisticated instruments, mostly limited to core facilities (i.e., tandem MS methods), long and expensive chromatography without specific internal standards for each AA (i.e., HPLC-ultraviolet and HPLC-fluorescence detector), or unstable derivatization (GC-MS). Here we describe a method with high throughput, stable derivatization, high precision and recovery, and potentially more affordable than most existing methods. This method could help dairy nutrition","PeriodicalId":94061,"journal":{"name":"JDS communications","volume":"5 6","pages":"Pages 745-750"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141840488","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

Genomic prediction of male fertility in Brown Swiss cattle 棕色瑞士牛雄性繁殖力的基因组预测

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2023-0533

Hendyel A. Pacheco , Attilio Rossoni , Alessio Cecchinato , Francisco Peñagaricano

Bull fertility has been recognized as an important factor affecting dairy herd fertility. The objective of this study was to assess the feasibility of predicting male fertility in Brown Swiss cattle using genomic data. The dataset consisted of 1,102 Italian Brown Swiss bulls with sire conception rate (SCR) records and genotype data for roughly 480k SNP. The analyses included the use of linear kernel-based regression models fitting all SNPs or incorporating markers with large effect. Predictive performance was evaluated in 5-fold cross-validation using the correlation between observed and predicted SCR values and mean squared error of prediction. The entire SNP set exhibited predictive correlations around 0.19. Interestingly, the inclusion of 2 markers with large effect yielded predictive correlations around 0.32. Overall, using linear kernel-based models fitting markers with large effect is a promising approach. Our findings could help Brown Swiss breeders make enhanced genome-guided management and selection decisions on male fertility.

公牛的繁殖力被认为是影响奶牛群繁殖力的一个重要因素。本研究的目的是评估利用基因组数据预测褐瑞士牛雄性繁殖力的可行性。数据集包括 1,102 头意大利褐瑞士公牛，这些公牛有父系受胎率 (SCR) 记录和大约 480k SNP 的基因型数据。分析包括使用基于核的线性回归模型拟合所有 SNP 或纳入具有较大影响的标记。利用观测值和预测 SCR 值之间的相关性以及预测的均方误差，对预测性能进行了 5 倍交叉验证评估。整个 SNP 集的预测相关性约为 0.19。有趣的是，加入 2 个影响较大的标记后，预测相关性约为 0.32。总之，使用基于线性核的模型拟合大效应标记是一种很有前景的方法。我们的研究结果可帮助布朗瑞士育种者在基因组指导下对雄性繁殖力做出更好的管理和选择决策。

引用次数: 0

Diurnal shifts of rumen fermentation and microbial profiles revealed circadian rhythms of rumen bacteria, methanogens, and protozoa under high-grain and high-forage diets 瘤胃发酵和微生物特征的昼夜变化揭示了高谷物和高饲草日粮条件下瘤胃细菌、甲烷菌和原生动物的昼夜节律

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2023-0526

Yangyi Hao , Jianming Xia , Wei Wang , Yajing Wang , Zhijun Cao , Hongjian Yang , Linshu Jiang , Zhu Ma , Kangkang Chu , Shuang Wang , Le Luo Guan , Shengli Li

In this study, we investigated how the composition and population of rumen microbiota shifted in response to diurnal oscillations under 2 different diets (high grain vs. high forage). Five multiparous Holstein dairy cows with similar BW, DIM, and parity were enrolled in this study. The cows were fed high-grain (HG) diet for 21 d and then shifted to high-forage (HF) diet in the next 21 d (7-d washout and 14-d experimental period). During the experimental period, DMI and rumination activity were recorded, and rumen fluid was collected 8 times postfeeding every 6 h during the last 2 d of each dietary feeding period. The rumen microbial (bacterial, archaeal, and protozoal) population and composition were assessed using quantitative PCR and amplicon sequencing, respectively. The daily dynamic of measurements was assessed using the cosinor model. The associations between microbial taxa and rumen fermentation profiles were assessed using the linear mixed model, in which the cows were termed as random intercept effects. Daily rhythmicity was observed for DMI, rumination activity, and rumen fermentation profiles under both diets. Additionally, rumination time, rumen pH, and acetate/propionate ratio had a higher mesor (the average level of diurnal fluctuations) under HF diet than in HG diet. The amplitude (the distance between the peak and mesor) of DMI, rumen pH, ammonia nitrogen, and total volatile acid concentration were higher under the HG diet than in the HF diet. Although no significant diurnal oscillation was observed for the rumen microbial population, the relative abundance of 14 bacterial genera, 1 protozoal genus, and 2 archaeal species had significant diurnal oscillations under both HF and HG diets. Among them, the bacterial genera Ruminococcus and Colidextribacter had time at peak of rhythm within 0 to 12 h after feeding, which were also negatively associated with the rumen acetate/propionate ratio. The bacterial genus Rikenellaceae_RC9_gut_group had time at peak of rhythm within 12 to 24 h after feeding, which was also positively associated with the ruminal acetate/propionate ratio. Our study illustrated the daily dynamic on the rumen microbiota population and composition under different diets, and also identified the feeding-responsive rumen microbiota, highlighting that a more targeted approach is needed to manipulate rumen microbiota.

在这项研究中，我们调查了在两种不同日粮（高谷物和高饲料）条件下，瘤胃微生物群的组成和数量如何随昼夜振荡而变化。本研究选取了五头体重、DIM 和胎次相似的多胎荷斯坦奶牛。这些奶牛先饲喂高谷物（HG）日粮 21 天，然后在接下来的 21 天内改喂高饲草（HF）日粮（7 天冲洗期和 14 天实验期）。在实验期间，记录DMI和瘤胃活动，并在每个日粮饲喂期的最后2 d，每6 h收集8次饲喂后的瘤胃液。分别使用定量 PCR 和扩增子测序法评估瘤胃微生物（细菌、古细菌和原生动物）的数量和组成。使用 cosinor 模型评估了测量结果的日动态。微生物类群与瘤胃发酵曲线之间的关系采用线性混合模型进行评估，其中奶牛被称为随机截距效应。在两种日粮条件下，DMI、反刍活动和瘤胃发酵曲线都呈现出日节律性。此外，高频日粮的反刍时间、瘤胃pH值和乙酸盐/丙酸盐比率的中间值（昼夜波动的平均水平）高于低频日粮。HG日粮的DMI、瘤胃pH、氨氮和总挥发性酸浓度的振幅（峰值与中值之间的距离）高于HF日粮。虽然瘤胃微生物种群没有观察到明显的昼夜振荡，但14个细菌属、1个原生动物属和2个古细菌属的相对丰度在HF和HG日粮中都有明显的昼夜振荡。其中，反刍球菌属（Ruminococcus）和 Colidextribacter 属（Colidextribacter）的节律峰值出现在采食后 0 至 12 h 内，且与瘤胃乙酸盐/丙酸盐比率呈负相关。Rikenellaceae_RC9_gut_group细菌属在采食后12至24小时内达到节律峰值，这也与瘤胃乙酸盐/丙酸盐比率呈正相关。我们的研究说明了在不同日粮条件下瘤胃微生物群数量和组成的日动态变化，同时也确定了饲喂反应性瘤胃微生物群，强调了需要一种更有针对性的方法来操纵瘤胃微生物群。

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引用次数: 0

Monitoring mammary gland development in preweaning dairy heifers using ultrasound imaging 利用超声波成像技术监测断奶前奶牛乳腺发育情况

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2024-0586

Alysia L. Vang , Tiago Bresolin , Waneska S. Frizzarini , Joana P. Campolina , Guilherme L. Menezes , Guilherme J.M. Rosa , Joao R.R. Dorea , Laura L. Hernandez

Existing literature on the long-term effects of nutritional manipulation on milk production is incomplete and inconsistent as animals are typically culled before lactation. In addition, longitudinal studies are rarely conducted due to high costs and constraints related to tissue sampling; therefore, additional research is necessary to better understand the effect of early nutrition and growth on subsequent growth and milk production. Thirty Holstein heifer calves were pair-fed high (H; 27% CP and 20% fat) or low (L; 22% CP and 15%) milk replacers. Mammary gland ultrasound images and BW were collected twice weekly, and blood samples weekly, for the first 8 wk of life. Calves fed H had higher ADG and mammary gland growth through 8 wk of life. Calves from the H group also had larger fat pads at 8 wk of age. Glucose and insulin concentrations were increased in H calves compared with L calves, whereas nonesterified fatty acid concentrations were not different between treatments. Our results suggest that ultrasound is a practical, noninvasive tool to monitor udder development preweaning, although additional research is necessary to improve image analysis techniques to analyze tissue composition. Our preliminary work provides data suggesting that the use of mammary gland ultrasound could provide a method of longitudinal analysis of the effects of preweaning nutrition on milk production.

由于动物通常在泌乳前就被宰杀，因此有关营养调控对产奶量的长期影响的现有文献既不完整也不一致。此外，由于成本高昂和组织取样的限制，很少进行纵向研究；因此，有必要开展更多研究，以更好地了解早期营养和生长对后续生长和产奶量的影响。30 头荷斯坦小母牛配对饲喂高（H；27% CP 和 20% 脂肪）或低（L；22% CP 和 15% 脂肪）代乳品。在犊牛出生后的头 8 周内，每周收集两次乳腺超声波图像和体重，每周收集一次血液样本。饲喂 H 组的犊牛在出生后 8 周内的平均日增重和乳腺生长较高。H组的犊牛在8周龄时脂肪垫也更大。与 L 组犊牛相比，H 组犊牛的葡萄糖和胰岛素浓度增加，而非酯化脂肪酸浓度在不同处理之间没有差异。我们的研究结果表明，超声波是监测断奶前乳房发育的一种实用、非侵入性工具，但还需要进行更多的研究来改进图像分析技术，以分析组织成分。我们的初步工作提供的数据表明，使用乳腺超声波可以提供一种纵向分析断奶前营养对产奶量影响的方法。

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引用次数: 0

Estimation of the nutrient variation in feed delivery and effects on lactating dairy cattle 估计饲料中营养成分的变化及其对泌乳奶牛的影响

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2024-0564

A.L. Carroll , K.J. Hanford , C. Abney-Schulte , P.J. Kononoff

Diets formulated for dairy cattle are designed to supply nutrients, but rations delivered to the animal may deviate from original formulations, resulting in implications for milk production, composition, and even pregnancy rate. The objective of this study was to evaluate retrospective feed mixing records collected from 8 commercial dairy farms over 52 wk. Farms ranged from 2,982 to 29,783 animals, producing 31.8 ± 5.93 (±SD) kg of milk with 4.14 ± 0.461% fat and 3.26 ± 0.218% protein. Data collected included daily TMR nutrient deviation, calculated as diet nutrient content minus the observed divided by the formulated diet concentrations of CP, fat, NDF, and starch. Data were analyzed with fixed effects of time (modeled as 28-d periods) and days of positive nutrient deviation in fat, CP, NDF, and starch with each nutrient alone and in combination with the other nutrients, random effects of herd, and repeated measure of time within herd. The nutrient deviation by farm averaged (±SD) 1.68 ± 2.655, 2.28 ± 4.473, 1.75 ± 2.621, and 1.47 ± 2.147% for CP, fat, NDF, and starch, respectively. Days of positive nutrient deviation per period averaged (±SD) 25.5 ± 3.47, 25.5 ± 3.72, 25.6 ± 3.49, and 25.9 ± 2.61, respectively. Dry matter intake (DMI; 17.2 ± 1.78 kg/d) decreased with increasing positive deviation days in starch (−0.0483 ± 0.01265) and increased with increasing positive deviation days in CP (0.0211 ± 0.00942). Milk yield (31.4 ± 2.50 kg/d) increased with positive deviation days in starch (0.0486 ± 0.02110) and decreased with increased positive deviation days in NDF (−0.0298 ± 0.02202). Finally, pregnancy rate (21.7 ± 4.34) increased with increasing positive deviation days in fat (0.385 ± 0.1635) and decreased with increasing positive deviation days in CP (−0.420 ± 0.1879). For these models, period significantly affected milk yield but was not observed to affect pregnancy rate and DMI. Results suggest farm and nutrient type were significant sources of variation, and overall, farms overfeed nutrients CP, fat, NDF, and starch 92% of the days of a 28-d period.

为奶牛配制的日粮旨在提供营养，但提供给动物的日粮可能会偏离最初的配方，从而对奶牛的产奶量、成分甚至妊娠率产生影响。本研究的目的是评估从 8 个商业奶牛场收集的 52 周内的饲料混合回顾性记录。牧场的牲畜数量从 2,982 头到 29,783 头不等，牛奶产量为 31.8 ± 5.93（±SD）千克，脂肪含量为 4.14 ± 0.461%，蛋白质含量为 3.26 ± 0.218%。收集的数据包括每日 TMR 营养偏差，计算方法是日粮营养含量减去观察值，再除以配方日粮中 CP、脂肪、NDF 和淀粉的浓度。分析数据时使用了时间（以 28 天为一个周期）和脂肪、CP、NDF 和淀粉中每种营养素单独或与其他营养素混合的正营养偏差天数的固定效应、牛群的随机效应和牛群内时间的重复测量效应。各牧场 CP、脂肪、NDF 和淀粉的营养偏差平均值（±SD）分别为 1.68 ± 2.655%、2.28 ± 4.473%、1.75 ± 2.621% 和 1.47 ± 2.147%。每期营养成分正偏差天数平均值（±SD）分别为 25.5 ± 3.47、25.5 ± 3.72、25.6 ± 3.49 和 25.9 ± 2.61。干物质摄入量（DMI；17.2 ± 1.78 kg/d）随着淀粉正偏差天数的增加而减少（-0.0483 ± 0.01265），随着CP正偏差天数的增加而增加（0.0211 ± 0.00942）。产奶量（31.4 ± 2.50 kg/d）随着淀粉正偏差天数的增加而增加（0.0486 ± 0.02110），随着 NDF 正偏差天数的增加而减少（-0.0298 ± 0.02202）。最后，妊娠率（21.7 ± 4.34）随脂肪正偏差天数（0.385 ± 0.1635）的增加而增加，随 CP 正偏差天数（-0.420 ± 0.1879）的增加而减少。在这些模型中，时期对产奶量有明显影响，但未观察到对怀孕率和DMI有影响。结果表明，牧场和营养物质类型是重要的变异来源，总体而言，牧场在 28 天期间有 92% 的天数过量饲喂营养物质 CP、脂肪、NDF 和淀粉。

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引用次数: 0

Oro-ruminal sampling device and technique for rapid collection of rumen content and improved recovery of solid fractions for microbiome analysis 用于快速收集瘤胃内容物和改进微生物组分析固体组分回收的瘤胃取样装置和技术

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2023-0536

F.E. Miccoli , R.I. Galarza , N. Juliano , S. Ferreyra , S. Maresca , S. López-Valiente , L.D. Guerrero , R.A. Palladino , R.I. Albornoz

Rumen fistulation is a widely used procedure that allows for collection of ruminal contents. However, fistulation is an invasive and costly procedure that generally limits the number of animals that can be recruited for experiments, thus encouraging the use of alternative techniques such as the intra-esophageal tube technique. One of the challenges of this technique is the limited ability to collect solid fractions from the rumen content pool, which may affect the microbial community structure in the sample, particularly affecting the recovery and characterization of solid adherent bacteria. We developed an intra-esophageal tube rumen sampling technique and device referred to as the “Rumen Sampler MG” with the aim of increasing the recovery of solid fractions from rumen content compared with other oro-ruminal sampling methods. The Rumen Sampler MG device consists of a manual pump fitted with a barometer and an intra-esophageal flexible polyvinyl chloride (PVC) tube with beveled terminal edge allowing for minimal clogging of the sampling tubing and a rapid flux of contents being sampled. Nine lactating Holstein-Friesian dairy cows (554.6 ± 25.2 kg of BW; 8.3 ± 3.3 DIM; ± SD) were recruited to evaluate the proposed method. During the procedure, animals were safely restrained in a chute and administered with a low dosage of a neuroleptic drug to reduce animal stress during sampling. An endoscopic camera was inserted into the reticulo-rumen through the esophagus to identify the sampling location and determine the length of the sampling tube necessary to reach the desired location. Following, the intra-esophageal sampling tube connected to a manual pump was inserted for collection of rumen contents. Samples collected did not present visual evidence of saliva contamination (e.g., high viscosity) and their pH ranged within expected values (6.33–7.04) for samples collected from the reticulo-rumen. Each sample contained 35% to 40% wet solids volume. Individual dry matter intake and milk production of cows continued to increase after sampling as expected for cows in the early postpartum period, suggesting that the sampling procedure did not affect cow performance. Results from microbiome analysis of rumen content samples suggest that the relative abundances of the main bacterial phyla are consistent with those from samples collected from dairy cows via rumen fistula in previous studies. The device and technique proposed allow for adequate samples of ruminal liquid and solid contents to be collected for microbiome analysis without disruption of animal performance.

瘤胃造瘘是一种广泛使用的收集瘤胃内容物的方法。然而，瘘管法是一种侵入性且成本高昂的程序，通常限制了可用于实验的动物数量，因此鼓励使用替代技术，如食管内插管技术。这种技术面临的挑战之一是从瘤胃内容物池中收集固体部分的能力有限，这可能会影响样本中的微生物群落结构，尤其是影响固体附着细菌的回收和特征描述。我们开发了一种食管内瘤胃采样技术和装置，称为 "瘤胃采样器 MG"，目的是与其他口腔瘤胃采样方法相比，提高瘤胃内容物中固体部分的回收率。瘤胃采样器 MG 装置由一个装有气压计的手动泵和一个食道内柔性聚氯乙烯（PVC）管组成，该管的末端边缘为斜面，可最大程度地减少采样管的堵塞，并使采样内容物快速流动。我们招募了九头泌乳荷斯坦-弗里斯兰奶牛（体重 554.6 ± 25.2 千克；8.3 ± 3.3 DIM；± SD）来评估所建议的方法。在采样过程中，动物被安全地束缚在一个滑槽中，并服用低剂量的神经安定药物，以减少采样过程中的动物应激反应。将内窥镜照相机通过食道插入网状结肠，以确定取样位置，并确定到达所需位置所需的取样管长度。随后，插入连接手动泵的食道内采样管，收集瘤胃内容物。采集的样本没有唾液污染的直观证据（如高粘度），其 pH 值在网状瘤胃样本的预期值（6.33-7.04）范围内。每个样本都含有 35% 至 40% 的湿固体。采样后，奶牛的个体干物质摄入量和产奶量继续增加，符合产后早期奶牛的预期，表明采样程序不会影响奶牛的生产性能。对瘤胃内容物样本进行微生物组分析的结果表明，主要细菌门类的相对丰度与以往研究中通过瘤胃瘘管从奶牛体内采集的样本一致。所提出的装置和技术可收集足够的瘤胃液体和固体内容物样本用于微生物组分析，而不会影响动物的生产性能。

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引用次数: 0

Relationship between plasma anti-Müllerian hormone concentrations in female Holstein calves immediately after birth and milk yield and composition in dams during early to mid gestation 荷斯坦雌性犊牛出生后血浆中抗苗勒氏管激素的浓度与妊娠早中期母牛的产奶量和成分之间的关系

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2024-0543

Saki Morimatsu, Nagisa Nagami, Chiho Kawashima

The energy status of dams during the early stages of gestation may affect ovarian reserves. It was hypothesized that greater milk yield and composition during the early stages of gestation may suppress the number of primordial follicles in the fetuses of dairy cattle. This study aimed to evaluate the anti-Müllerian hormone (AMH), used as an indicator of ovarian reserves, in female Holstein calves immediately after birth. It also examined the relationship between AMH concentrations and the milk yield and composition of dams during early pregnancy. A total of 85 female Holstein calves (born to first-calving cows [nulliparous heifers], n = 31; second-calving [primiparous] cows, n = 22; and third- or subsequent-calving [multiparous] cows, n = 32) were examined. Blood samples were collected from the female calves after birth and before the first colostrum feeding for the analysis of plasma AMH concentrations. Data on daily milk yield and monthly milk composition during the first to sixth month of pregnancy were additionally collected from milking dams. The plasma AMH concentrations ranged from 0.106 to 1,542.3 pg/mL, with an average of 291.6 ± 30.5 pg/mL. No significant differences were observed among the plasma AMH concentrations in female calves born from nulliparous heifers, primiparous cows, or multiparous cows. Primiparous cows exhibited numerous negative correlations between the plasma AMH concentrations of their female calves immediately after birth and the daily milk yield and milk composition from the first to the fourth month of pregnancy; however, no correlation was observed in multiparous cows. Overall, large individual variations were observed in the plasma AMH concentrations immediately after birth. Both milk yield and the amount of milk components strongly influenced plasma AMH concentrations in calves immediately after birth in primiparous cows in the growth phase. These factors, conversely, did not affect the plasma AMH concentrations of calves in multiparous cows. The results of this study suggest that high-producing pregnant primiparous cows devote more energy to their growth and lactation, potentially compromising the reproductive potential of their offspring. Thus, improving the feeding management of primiparous cows with the goal of increasing the fertility of their progeny will help high-yielding dairy cows reproduce more successfully.

妊娠早期母牛的能量状况可能会影响卵巢储备。据推测，妊娠早期较高的产奶量和牛奶成分可能会抑制奶牛胎儿原始卵泡的数量。本研究旨在评估作为卵巢储备指标的荷斯坦雌性犊牛出生后的抗缪勒氏管激素（AMH）。研究还考察了 AMH 浓度与妊娠早期母牛的产奶量和组成之间的关系。共检测了 85 头荷斯坦雌性小牛（初产母牛[无阴道小母牛]，n = 31；二产母牛[初产母牛]，n = 22；三产或后产母牛[多产母牛]，n = 32）。在雌性犊牛出生后和第一次喂初乳前采集血液样本，用于分析血浆中的 AMH 浓度。此外，还收集了挤奶母牛怀孕第一至第六个月期间的日产奶量和月牛奶成分数据。血浆AMH浓度范围为0.106至1,542.3 pg/mL，平均为291.6 ± 30.5 pg/mL。无产仔数母牛、初产母牛和多产仔数母牛所产雌性犊牛的血浆AMH浓度无明显差异。初产母牛的犊牛出生后血浆AMH浓度与妊娠第1个月至第4个月的日产奶量和牛奶成分之间存在许多负相关；但在多胎母牛中未观察到相关性。总体而言，犊牛出生后血浆AMH浓度的个体差异很大。对于处于生长阶段的初产母牛，产奶量和牛奶成分的数量对出生后犊牛的血浆AMH浓度有很大影响。相反，这些因素并不影响多胎奶牛犊牛的血浆AMH浓度。研究结果表明，高产初产妊娠母牛在生长和泌乳过程中会消耗更多的能量，这可能会影响其后代的繁殖潜力。因此，改善初产奶牛的饲养管理以提高其后代的繁殖力，将有助于高产奶牛更成功地繁殖。

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引用次数: 0

Understanding the dynamics of mastitis in milk yield: Decoding onset and recovery patterns in response to mastitis occurrence 了解乳腺炎对牛奶产量的动态影响：解码乳腺炎发生时的发病和恢复模式

JDS communications

Pub Date : 2024-11-01 DOI: 10.3168/jdsc.2024-0579

A.L.L. Sguizzato , T.E. da Silva , J.C.C. Chagas , A.M. Argüelo , N.M. Gonçalves , M.I. Marcondes

No recent study has attempted to model daily milk losses before and after mastitis onset and the moment when it begins. Thus, we aimed to describe the impact of mastitis on milk production based on mastitis level and moment of occurrence. We used data from 11 dairy farms, and the dataset consisted of 885,759 daily individual milk test records from 3,508 cows in different lactations, with an average milk yield (MY) from January 2017 to December 2022. We modeled the impact of mastitis severity (i.e., 1 [mild] and 2 [severe]) based on the drop and recovery of MY following 3 steps. First, we removed milk recorded on the day of diagnosis of mastitis from the dataset and fitted a Wood's curve for each cow and parity. Second, we returned the mastitis data to the dataset and estimated the residual milk loss due to mastitis from 15 d before to 30 d after the mastitis event. Third, we used generalized additive mixed effect models to estimate the residual milk loss, including farm as a random effect. In addition to the random effect of the farm, we also included the predicted milk yield (by Wood's curve) over the influence of mastitis, the day effect before and after mastitis incidence, and the interaction between the predicted value of mastitis and days. On average, mastitis level 2 resulted in a more severe MY drop in all represented stages of lactation (80, 170, and 260 DIM), suggesting a higher loss close to the lactation peak, approximately 130 kg more than mastitis level 1. Moreover, the occurrence of mastitis case level 1 during the early phase of lactation (DIM 80) can cause an average milk loss of 158 L and mastitis level 2, an average loss of 288 L. The estimations suggest that milk drop occurs 14 to 4 d before mastitis onset and can last until 15 to 25 d from the diagnosis, which would be the necessary time for a cow to re-establish their predicted MY. Therefore, our study brings new perspectives to investigate MY drop and recovery due to mastitis infections and how much mastitis can deplete and impair milk production.

最近的研究还没有试图模拟乳腺炎发生前后和开始时的每日牛奶损失。因此，我们旨在根据乳腺炎的程度和发生时刻来描述乳腺炎对牛奶产量的影响。我们使用了 11 个奶牛场的数据，数据集包括 3,508 头不同泌乳期奶牛的 885,759 份每日个体牛奶检测记录，平均产奶量（MY）从 2017 年 1 月至 2022 年 12 月。我们根据 MY 的下降和恢复情况，按照三个步骤对乳腺炎严重程度（即 1 级 [轻度] 和 2 级 [重度]）的影响进行建模。首先，我们从数据集中移除乳腺炎确诊当天记录的牛奶，并为每头奶牛和每个闰位拟合伍德曲线。其次，我们将乳腺炎数据返回数据集，并估算乳腺炎事件发生前 15 天至发生后 30 天内因乳腺炎造成的剩余牛奶损失。第三，我们使用广义加性混合效应模型估算残余奶量损失，并将牧场作为随机效应。除了牧场的随机效应外，我们还加入了乳腺炎影响下的预测产奶量（通过伍德曲线）、乳腺炎发生前后的日效应以及乳腺炎预测值与日之间的交互作用。平均而言，乳房炎 2 级导致泌乳期所有阶段（80、170 和 260 DIM）的 MY 下降更严重，表明接近泌乳高峰时损失更大，比乳房炎 1 级多出约 130 千克。此外，在泌乳早期（DIM 80）发生乳腺炎 1 级病例可造成平均 158 升的牛奶损失，而乳腺炎 2 级病例可造成平均 288 升的牛奶损失。估计结果表明，牛奶下降发生在乳腺炎发病前 14 到 4 d，并可持续到诊断后的 15 到 25 d，这将是奶牛重新建立预测年生产力所需的时间。因此，我们的研究为研究乳腺炎感染导致的MY下降和恢复以及乳腺炎对产奶量的消耗和损害程度提供了新的视角。

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引用次数: 0