生乳中体细胞数对酸奶成品品质的影响

本文以含有不同体细胞数（SCC）的生乳为主要原料,选用常用发酵剂（保加利亚乳杆菌和嗜热链球菌按1：1比例配合）,采取相同的试验条件生产酸奶,测定成品酸奶的粘度、色泽、组织状态及pH值的变化情况,从而得出不同体细胞数的生乳对酸奶成品品质的影响。     

生鲜驴乳体细胞数、芽孢菌数和嗜冷菌数检测

从乌鲁木齐市郊某养驴场采集57头份生鲜驴乳样本,测定体细胞数、芽孢菌数、耐热芽孢数和嗜冷菌数。结果表明:驴乳平均体细胞数(8.35±27.25)万个/ml,芽孢菌数(8.0±5.8)CFU/ml,耐热芽孢数(2.1±1.8)CFU/ml,嗜冷菌(122.4±156.9)CFU/ml。生鲜驴乳体细胞数和所检微生物指标均低于牛乳。     

内蒙古地区生鲜乳中体细胞数分析及其对产奶量、乳品质的影响

本试验旨在比较2017年内蒙古地区生鲜乳中的体细胞数与主要奶业国体细胞数标准,对比奶罐奶和散卖奶体细胞数,同时分析生鲜乳中的体细胞数与产奶量及乳成分间相关性,旨在为生鲜乳质量安全评定及控制提供参考依据。试验于2017年采集内蒙古地区9个盟市673批次生鲜乳样品,采用Foss Mickro-FT120乳成分分析仪测定生鲜乳中乳脂肪、乳蛋白、非脂乳固体、乳糖、总固体含量,同时采用丹麦Chemomete SCC-100体细胞仪进行体细胞计数。结果表明:1) 2017年内蒙古地区生鲜乳中的体细胞数为37. 7×10~4个/mL,低于欧盟(40. 0×10~4个/mL)、新西兰(40.0×10~4个/mL)、加拿大(50.0×10~4个/mL)和美国(75.0×10~4个/mL)的生鲜乳中体细胞限定值。2)家庭散养模式散卖奶中的体细胞数(55.8×10~4个/mL)显著高于规模化牧场奶罐奶中的体细胞数(37.7×10~4个/mL)(P<0.05)。3)生鲜乳中的体细胞数与产奶量呈极显著负相关(P<0.01),相关系数为-0.190;与乳脂肪含量之间无显著相关性(P>0.05);与乳蛋白、乳糖、非脂乳固体及总固体含量之间存在极显著负相关(P<0.01),相关系数分别为-0.149、-0.295、-0.283、-0.115。由此可见,内蒙古地区生鲜乳中的体细胞数管控较好,达到甚至超过了欧美主要奶业国标准。家庭式散养方式生产的生鲜乳质量安全水平低于规模化养殖方式。生鲜乳中体细胞数增高会导致产奶量下降及乳品质的改变。     

体细胞数对乳品企业质量安全风险控制的意义

许多发达国家已将体细胞数（SCC）作为衡量生鲜乳质量标准的重要指标之一。体细胞数越低，生鲜乳质量越高；体细胞数越高，对生鲜乳的质量影响越大，并会对鲜奶的保质期和下游乳制品，如酸奶、奶酪等的产量、质量、风味等产生极大的不利影响。本文从体细胞数对生鲜乳质量控制方面的监督作用进行了分析，说明体细胞数对乳品企业质量安全风险控制具有重要意义。     

牛乳体细胞数影响因素、控制及牛群管理

1体细胞数概念、影响及检测方法 生鲜乳中体细胞数（SCC），是指每毫升奶中的细胞总数，多数是白细胞（即巨噬细胞、嗜中性白细胞和淋巴细胞），其中约占牛体细胞数的98％～99％，其他1％～2％的体细胞是乳腺组织脱落的上皮细胞，其数量反映了牛乳产量、质量及牛体的健康状况。当乳腺被感染或受机械损伤后，体细胞会上升。     

伊宁市区生鲜牛乳中微生物污染程度检测与分析

为了研究伊宁市区生鲜牛乳中微生物污染情况,试验对菌落总数、大肠菌群数和沙门菌数进行检测。结果表明:伊宁市区生鲜牛乳来源不同,奶源质量有较大差别。散奶(户)牛乳中的菌落总数高于售奶亭牛乳的菌落总数,最高达到5.17×104cfu/mL,但是均没有超过国家标准规定的指标(2×106cfu/mL)。     

内蒙古不同地区奶牛产奶量及乳品质比较研究

目的]对内蒙古不同地区生鲜牛乳进行质量等级划分,并对农区与牧区、规模化牧场与散养户奶牛的单产以及乳品质进行比较。[方法]于2023年10月分别从呼和浩特市规模化奶牛养殖场、呼和浩特市散养户奶牛场、呼伦贝尔市奶牛养殖场、锡林郭勒盟奶牛养殖场采集生鲜乳样品各30批次,共120批次,并收集各奶牛场生产记录信息。测定不同地区乳样的乳成分(乳脂率、乳蛋白率、总固体含量、非脂乳固体含量、乳糖含量)、体细胞数及菌落总数;依据《生牛乳质量分级》(NY/T 4054—2021)对3个地区的生鲜乳进行质量等级划分;采用统计学方法比较农区(呼和浩特市)与牧区(呼伦贝尔市及锡林郭勒盟)、呼和浩特市规模化牧场与散养户奶牛的平均单产以及生鲜乳品质。[结果]锡林郭勒盟牛场生鲜乳的乳脂率和菌落总数(6.16%,83.10×10⁴CFU/mL)显著(P<0.05)高于呼和浩特市(3.96%,14.05×10⁴CFU/mL)和呼伦贝尔市(4.15%,38.94×10⁴CFU/mL);呼伦贝尔市牛场的生鲜乳体细胞数(39.99万个/mL)显著(P<...     

牛乳电导率值与体细胞数相关性的研究

试验以随机采集的奶牛乳样为研究对象，对乳样的电导率值与体细胞数进行了测定与分析。结果显示，体细胞数在50万个/ml以下时，电导率值在4．40～4．75ms／cm之间；体细胞数在50万～500万个／ml时，电导率值在5．20～9．00ms／cm之间；体细胞数在500万／个ml时，电导率值在9．00ms／cm以上。结果表明，牛乳电导率的变化与体细胞数呈正相关，可利用牛乳体细胞数与电导率变化的相关关系判断奶牛隐性乳房炎发病程度。     

采用SCC-100型体细胞计数仪研究不同保存条件对生鲜乳体细胞数的影响

为了研究不同保存条件下生鲜乳体细胞数(SCC)的变化规律,试验采用SCC-100型体细胞计数仪,探讨防腐剂、保存温度和保存时间对生鲜乳中体细胞数的影响。结果表明:添加防腐剂并在4℃保存的生鲜乳,6 d内体细胞数无显著差异(P0.05),但无防腐剂乳样只能保存3 d。30℃高温条件对生鲜乳中体细胞数影响较大,即使添加防腐剂,从保存第3天开始体细胞数仍极显著降低(P0.01);而无防腐剂只能保存不到1 d。生鲜乳体细胞数与保存温度和保存时间存在极显著负相关(P0.01)。说明4℃添加防腐剂的乳样最适合使用SCC-100型体细胞计数仪进行体细胞测定,在该条件下可最大限度地保证乳样体细胞数的稳定性。     

乳中体细胞数在牛奶生产中的监控作用

1　牛乳中体细胞数牛乳中的体细胞 (SomaticCellCount,SCC) ,是指每毫升奶中的细胞总数 (挤奶前的第一把奶 ) ,多数是白细胞 (即巨噬细胞、嗜中性白细胞和淋巴细胞 ) ,其中约占牛体细胞数的 98%～ 99% ,其他 1 %～ 2 %的体细胞是乳腺组织脱落的上皮细胞 ,其数量反映了牛奶产量、质量及牛只的健康状况。在正常情况下 ,牛奶体细胞数不可能为零 ,牛奶中体细胞数一般在 2 0万～ 30万个 /mL。当乳房外伤或发生疾病产生炎症时 ,机体将大量的白细胞分泌进入乳房以清除感染 ,体细胞数一般都超过 5 0万个 /mL(Ruegg ,1 997)。因此 ,牛奶中体细胞…     

In vitro evaluation of the 18 and 36 kg Securos Cranial Cruciate Ligament Repair System

OBJECTIVE: To evaluate the mechanical properties of the 18 and 36 kg Securos Cranial Cruciate Ligament Repair System. STUDY DESIGN: In vitro mechanical evaluation. SAMPLE POPULATION: Loop constructs of 18, 27, and 36 kilogram test (kgt) nylon leader line (NLL) secured with Securos crimp-clamps (SCC, n=40 per NLL test weight) or by a clamped square knot (CSK; n=40/NLL test weight). METHODS: The 36 kg SCC were used for the 27 and 36 kgt NLL, and 18 kg SCC were used for the 18 kgt NLL. Loop constructs were mounted on a material testing machine, and distracted at 500 mm/min for static tests, and for cyclic tests at 500 mm/min to a distraction limit of 6 mm (18 kgt) or 7.5 mm (27 and 36 kgt) for 49 cycles, until failure. Constructs were tested at 20 degrees C except for 1 group of 27 kgt CSK loops tested at 40 degrees C. Load at failure, elongation, and stiffness was recorded and compared between groups under static or cyclic testing conditions. RESULTS: All 27 and 36 kgt loops failed by disruption of NLL contained within the knot or crimp-clamp, whereas 18 kgt SCC loops failed by the NLL pulling through the crimp-clamp. The 18 kg SCC loops had considerable variability in ultimate load and elongation (coefficient of variation 29.6% and 18.3%, respectively). There was no significant difference in elongation between 27.3 kgt CSK loops tested at 20 degrees C and 40 degrees C. Generally, in both static and cyclic testing, SCC constructs formed with 27.3 or 36.4 kgt NLL performed as well or better than CSK constructs, resulting in loops that were strong, underwent minimal elongation, and had high stiffness. CONCLUSION: The results support use of the 36 kg Securos system but not the 18 kg Securos system (with the clamp and crimping device used). The significantly lower load required for failure, slippage through the clamp, and substantial variability suggested that the crimp tube diameter or the crimping device tested may be inappropriate for use with 18 kgt NLL. CLINICAL RELEVANCE: Surgeons should be aware that crimp-clamp design is important in controlling suture slippage or breakage within the clamp, and that novel systems should undergo mechanical testing with the size suture material they are intended to secure before clinical use.     

The interrelationships between milkability traits and subclinical mastitis in cows

The investigation was conducted during 2005-2006 on 4010 dairy cows. Having performed statistical data analysis, we determined that the lowest somatic cell count (SCC) in Red and Red-White cow population was obtained when the milking time was 5-6 min., milking speed was higher than 1.5 kg/min., high milk flow was from 2.51 to 4 kg/min., and in Black-White cow population having a milking time was higher than 7 min., milking speed was from 1.01 to 2 kg/min., a high milk flow --from 2.01 to 4 kg/min. (p<0.001). In Red and Red-White cow population with subclinical mastitis, milking time was longer and milking speed was slower than in healthy cows. High milk flow values were least in healthy Black-White cow population. This determines a more equal milk flow which is desired in milking cows mechanically. Most sensitive to udder infection are 1st lactation cows which have a higher milk flow. A larger phenotype correlation coefficient in Red and Red-White cow population was between the SCC and milking time (-0.089, p<0.01) and between high milk flow (0.086, p<0.01) and milk yield (-0.071, p<0.05). However in Black-White cow population, correlation was found between SCC and milk yield (-0.117, p<0.01) and milking speed (-0.110, p<0.01). Contagious mastitis pathogens were identified in Red and Red-White cow milk samples primarily from productive cows having a milking speed of 1.01-1.5 kg/min., and in Black-White cow population having a milking speed of 1.51-2.0 kg/min.     

Effect of infectious status and parity on somatic cell count and California mastitis test in pampinta dairy ewes

The relationship between somatic cell counts (SCC) and California mastitis test (CMT) results according to the infectious status of mammary halves and parity of Pampinta dairy ewes was evaluated. Tests were associated to bacteriological analysis and classified into three groups: uninfected (negative culture), infected by minor pathogens and infected by major pathogens. Coagulase-negative Staphylococcus (32.4%), Micrococcus spp. (32.4%), Corynebacterium spp. (5.4%), and Bacillus spp. (1.4%) were the minor pathogens isolated, while Staphylococcus aureus (27%) and Escherichia coli (1.4%) were the major pathogens isolated. A good correlation was found between the CMT and SCC, which included inflammatory and epithelial cells (r = 0.64; P < 0.0001). SCC averages for the CMT scores shown in parentheses were 223 576 (0); 245,248 (1); 397,778 (2); 1,159,109 (3) and 2,460,833 (4) cells/ml. The correlation between SCC and the infectious status of udder halves was 0.58 (P < 0.0001). The relationship between SCC and CMT profiles and infectious status studied by a discriminant analysis showed, with an accuracy of 65%, three infectious status groups. SCC arithmetic means were 244,470 cells/ml for negative culture, 1,044,100 cells/ml for minor pathogens and 2,045,652 cells/ ml for major pathogens. With the exception of 1-year-old ewes, no significant differences were observed in SCC as affected by age or parity.     

Relationship between the somatic cell count in milk and reproductive function in peripartum dairy cows

The aim of the present study was to examine the effect of the somatic cell count (SCC) in milk on reproductive performance, such as pregnancy status in the prepartum period and ovarian function in the postpartum period, in dairy cows. Blood samples were collected every week from one month prepartum to parturition in order to measure the concentrations of 13,14-dihydro-15-keto-PGF_2α (PGFM), estrone sulfate (E1S) and progesterone. Milk samples were collected three times per week in both the prepartum (for one month before the dry period) and postpartum periods (for 3 months immediately after parturition) to measure the SCC. Progesterone was also determined in the whole milk of postpartum cows to define the day of the first ovulation. In the prepartum period, the maximum SCC negatively correlated with the pregnancy period (r = –0.77), but not the calf birth weight. Positive and negative correlations were observed between the average SCC and PGFM or progesterone concentrations in plasma, respectively (r = 0.84 or –0.92, respectively), at 39 weeks of pregnancy. In the postpartum period, a correlation was observed between the day of the first ovulation and both the average and maximum SCC (r = –0.74 and –0.75, respectively), whereas days open was not related to the SCC. These results suggest that a high SCC in the prepartum period may advance parturition by increasing PGF_2α and decreasing progesterone and that the first ovulation in the postpartum period was affected by a high SCC.     

线性模型对影响奶牛产奶性能的主要相关因素分析

利用一般线性模型研究各种因素对奶牛产奶性能的影响。牛场、胎次和产犊季节对奶牛产奶量影响差异极显著(P0.01),随着奶牛胎次的增加,奶牛产奶量增加;夏季产犊的奶牛产奶量最低,冬季产犊的最高;体细胞计数对奶牛产奶量没有显著性影响(P0.05),但随着体细胞数的增加,产奶量下降。牛场、胎次和体细胞计数对乳脂率有极显著的影响(P0.01),第三牛场平均乳脂率为4.38%,显著高于其他三个牛场;随着胎次的增加,乳脂率有下降趋势;随体细胞数增加,乳脂率升高;产犊季节对奶牛乳脂率没有显著影响(P0.05)。牛场、产犊季节和体细胞数对乳蛋白率的影响极显著(P0.01),体细胞数增加,乳蛋白率升高;夏季和秋季产犊的奶牛乳蛋白率较高,春季和冬季较低;胎次对乳蛋白率没有显著影响(P0.05)。表型相关分析表明:SCC与产奶量呈显著负相关(r=-0.158,P0.05),SCS与产奶量相关性接近显著水平(r=-0.140,P=0.055)。SCC/SCS与乳脂率、乳蛋白率呈正相关,但未达到显著性水平(P0.05)。     

Comparison of dendritic cell-mediated immune responses among canine malignant cells

Dendritic cell (DC) vaccination is one of the most attractive immunotherapies for malignancies in dogs. To examine the differences in DC-mediated immune responses from different types of malignancies in dogs, we vaccinated dogs using autologous DCs pulsed with keyhole limpet hemocyanin (KLH) and cell lysate prepared from squamous cell carcinoma SCC2/88 (SCC-KLH-DC), histiocytic sarcoma CHS-5 (CHS-KLH-DC), or B cell leukemia GL-1 (GL-KLH-DC) in vitro. In vivo inductions of immune responses against these tumor cells were compared by the delayed-type hypersensitivity (DTH) skin test. The DTH response against SCC2/88 cells were observed in dogs vaccinated with autologous SCC-KLH-DC, while the response was undetectable against CHS-5 and GL-1 cells in dogs vaccinated with autologous CHS-KLH-DC and GL-KLH-DC. Skin biopsies taken from DTH challenge sites were then examined for immunohistochemistry, and recruitment of CD8 and CD4 T cells was detected at the site where SCC2/88 cells were inoculated in dogs vaccinated with SCC-KLH-DC. By contrast, neither CD8 nor CD4 T cell infiltration was found at the DTH challenge site in the dogs vaccinated with CHS-KLH-DC or GL-KLH-DC. These findings may reflect that the efficacy of immune induction by DC vaccination varies among tumor types and that immune responses could be inducible in squamous cell carcinoma. Our results encouraged further investigation of therapeutic vaccination for dogs with advanced squamous cell carcinoma in clinical trials.     

Cellular localization of Visudyne® as a function of time after local injection in an in vivo model of squamous cell carcinoma: an investigation into tumor cell death

Objective To evaluate the effects of time on cellular localization of Visudyne^® after local injection. Animals Twenty athymic nude mice. Procedures A squamous cell carcinoma (SCC) cell line (A‐431) was injected into right and left dorsolumbar subcutaneous tissue of each mouse, representing treatment (T) and control (C) tumors. In experiment 1 (Exp 1; n = 10) and 2 (Exp 2; n = 10), the T tumors received a local injection of Visudyne^® (0.1 mg/cm³), and C tumors received an equal dose of 5% dextrose in water (D5W). Mice were randomly subdivided into two groups (A and B; n = 5 per group). Mice in Exp 1A and B were sacrificed 1 and 30 min after local injection, respectively. Experiment 1A and B tumors were evaluated by fluorescence microscopy to determine drug localization. Experiment 2A and B tumors were exposed to LED illumination 1 and 30 min after injection, respectively, and evaluated by transmission electron microscopy (TEM) to determine ultrastructural tumor cell damage. Results Fluorescence was detected within the cytoplasm of T tumors in both Exp 1A and B. Significance was detected in fluorescence intensity between T1 min vs. T30 min (P = 0.03) and between T1 min and C1 min tumors (P = 0.01), respectively. Tumors in Exp 2A and B demonstrated evidence of apoptotic cell death. Conclusions Fluorescence microscopy demonstrated higher Visudyne^® concentration within SCC cytoplasm of 1 min compared with 30‐min tumors. Transmission electron microscopy results revealed that tumors treated by photodynamic therapy (PDT) within 30 min of local injection undergo cellular apoptosis.     

The detection of mastitis in individual quarters using electrical conductivity or somatic cell concentration

In this investigation electrical conductivity (EC) and somatic cell concentration (SCC) were compared in 3 herds for their ability to correctly identify the infection status of quarters. For EC, thresholds of 6.0 and 6.8 mS/cm were used and comparisons were made between quarters within each cow. The method of comparison between quarters was the same as that described by the manufacturers of the AHI Mastitis Detector. For SCC a threshold of 500 x 10(3) cells/ml was used. For both EC and SCC considerable variation was found between herds for sensitivity (the proportion of quarters infected with a major pathogen and detected as abnormal), and specificity (the proportion of quarters free from infection and detected as normal). The mean sensitivity and specificity of EC for the three herds was 49% and 79% respectively, whereas for SCC the means were 71% and 81% respectively. The variation in sensitivity and specificity of EC between herds was attributed to differences in the distribution of EC for quarters of similar infection status. It was concluded that these differences in herd EC precluded the use of pre-determined EC thresholds which were applicable for detecting mastitis in all herds.     

Blood and milk cellular immune responses of mastitic non-periparturient cows inoculated with Staphylococcus aureus

Lymphocyte function and phenotype of peripheral blood and mammary gland cells were evaluated in non-periparturient cows before and at 1, 4 to 8 and 9 to 14 d after inoculation with Staphylococcus aureus, as expressed by percentage of CD3+, CD2+, and CD45R+ cells, antigen density of these markers per lymphocyte, and mitogen-induced blastogenesis. Milk bacterial counts and somatic cell counts (SCC) were also assessed. Mitogen-induced blastogenic responses were strong in blood and weak in mammary gland cells in all observations and positively correlated with the percent of CD45R+ cells. Significantly greater percentages of milk CD3+ lymphocytes and increased CD3, CD2, and CD45R antigen density per cell were observed after challenge. The blood CD3 and CD2 antigen density per lymphocyte and the milk CD2+ lymphocyte percent were negatively correlated with SCC (P ≤ 0.01). No mastitis (SCC ≤ 500 000 cells/mL) was observed in cows showing blood lymphocyte CD2 and CD3 antigen density indices ≥ 2.5 and 6, respectively. Forty-one percent of SCC values were predicted by the combined blood CD2 and milk CD3 antigen density (P ≤ 0.01). These findings support the hypotheses that mitogen-induced lymphocyte blastogenesis is not a valid test to assess mammary gland immunocompetence and that CD2 expression may facilitate immune responses by decreasing the number of T cell receptors required to achieve full activation.     

2018年天津市原料奶细菌总数、体细胞数及奶牛乳房炎病原菌、耐药基因调研报告

本研究旨在调查天津市原料奶细菌总数、体细胞数及乳房炎病原菌、耐药基因,了解全市原料奶的质量状况及引起奶牛乳房炎发生的主要原因。采集天津市5家乳品加工企业奶罐车的原料奶样品,用于检测体细胞数和菌落总数;采集天津市奶牛养殖场储奶罐奶样品,用于检测体细胞数;采集奶牛场临床型乳房炎发病乳区的牛奶样品,用于检测乳房炎病原菌及耐药基因。结果显示:2018年天津市乳品加工企业原料奶体细胞数平均值为44.65万/mL,标准差42.41万/mL,变异系数94.97%,最大值为225.50万/mL,最小值为1.20万/mL,SCC≤50万/mL的样品占74.37%,50万/mL200万/mL的样品占3.13%;细菌总数平均值11.54万CFU/mL,标准差26.28万CFU/mL,变异系数227.66%,最大值190.00万CFU/mL,最小值0.095万CFU/mL,细菌总数≤10万CFU/mL的样品占74.37%,10万CFU<细菌总数≤50万CFU/mL的样品占21.25%,50万CFU<细菌总数≤100万CFU/mL的样品占1.88%,100万CFU/mL<细菌总数≤200万CFU/mL的样品占2.50%。2018年天津市奶牛养殖场原料奶体细胞数平均值为38.81万/mL,标准差36.49万/mL,变异系数94.03%,最大值为210.00万/mL,最小值为0.80万/mL,SCC≤50万/mL的样品占79.17%,50万/mL200万/mL的样品占0.83%。乳房炎病原菌检测结果显示:36个样品检出病原菌,总检出率为94.74%;共检出8种病原菌,检出率最高的是乳房链球菌,检出率为73.68%,其他病原体检出率依次为:牛支原体34.21%,牛棒状杆菌13.16%,无乳链球菌10.53%,大肠杆菌5.26%,白色念球菌5.26%,停乳链球菌2.63%,铜绿假单胞菌2.63%。14个样品检出耐药基因,总检出率为36.84%;2种耐药基因的检出率分别为β-内酰胺耐药基因CTX-M934.21%,耐甲氧西林葡萄球菌耐药基因MecA 2.63%。研究表明,2018年天津市原料奶SCC及细菌总数大部分接近欧盟标准,但仍有待进一步提高;引起天津地区临床型乳房炎的3种主要致病菌为乳房链球菌、牛支原体和牛棒状杆菌。