不同保存条件对牛乳DHI指标测定值的影响

本试验通过在奶样中添加不同类型的防腐剂并在不同温度下保存,进行牛乳DHI指标的连续测定,研究不同保存条件对牛奶中乳脂、乳蛋白、乳糖、尿素氮含量及乳体细胞数的影响。结果表明,添加防腐剂本身对乳指标的影响保持在误差范围之内;-10℃对乳脂率的稳定性不利;4℃条件下,即使不添加防腐剂,也能保证乳脂、乳蛋白、乳糖及尿素氮含量的稳定;25℃以上的条件下,溴硝丙二醇的防腐效果非常优秀,可以基本保证6d以内样品的稳定保存,而重铬酸钾防腐效果表现不足,特别是在30℃条件下,重铬酸钾无法保证大部分测定指标的稳定。     

牛奶样品防腐剂的研制

本研究通过多次试验确定了牛奶样品防腐剂的适宜配方，研制成功牛奶样口防腐剂片剂，通过工厂试验证明第一天加牛奶１０ｍｌ，加一片防腐剂，以后每天加奶１０ｍｌ，连续加９ｄ，在２５℃下奶样可保存１２－１５ｄ，且对乳脂率无影响。     

防腐剂对DHI检测指标及防腐效果的影响

为探究奶牛生产性能测定(DHI)过程中奶样防腐剂的防腐效果及对乳品质指标的影响,本试验通过3种防腐剂的对比,对乳品质中的乳脂率、乳蛋白率、体细胞数、尿素氮含量进行连续测定,并且利用酒精试验检查防腐效果。结果表明,添加3种防腐剂后对乳脂率、乳蛋白率、体细胞数、尿素氮的影响均在标准要求的误差之内;添加防腐剂后乳脂率随着时间变化总体呈下降趋势,其中添加防腐剂Ⅱ的下降较为明显(P0.05);冷藏保存时乳蛋白率随着时间变化呈上升趋势(P0.05),防腐剂条件下可稳定保存5d;体细胞数在0～1d显著降低(P0.05),其中防腐剂Ⅰ影响最大,在2～4d内体细胞数呈上下波动,第5天开始有所增加(P0.05);尿素氮含量在冷藏保存下显著提高(P0.05),防腐剂保存时基本维持稳定;通过酒精试验发现,冷藏条件下,不加防腐剂的牛奶在第7天开始变质,第9天时完全变质;加入3种防腐剂后在第12天才开始变质,其中保鲜效果较好的为防腐剂Ⅱ。     

牛奶不同保存温度对其性能测定的影响

性能测定作为牛奶的一项重要基础性工作,如何保证从采样到检测各环节乳成分的稳定,对性能测定数据的准确性至关重要。在不同温度时添加防腐剂能够保证奶样在一定时间内保持稳定。本文主要综述在不同保存温度时是否添加防腐剂对乳成分检测值的影响。     

奶水牛乳中体细胞数与乳成分的相关分析

乳汁体细胞数(somatic cell count,SCC)是检查奶牛乳房炎和牛奶质量的指标,为了解南宁某规模化奶牛场奶水牛SCC情况及SCC与其他乳成分的关系,试验随机选取该场152份泌乳早期乳样,测定其SCC、乳汁比重、蛋白质、脂肪、总固形物、非脂固形物及乳糖的含量,并对其进行相关性分析。结果表明,SCC小于50万/mL的乳样占被检奶样总数的88.16%,大于100万/mL的占1.97%;乳汁比重、乳蛋白、乳糖和非脂固形物含量均随着SCC的升高而下降,而乳脂含量随着SCC的升高而呈上升趋势;SCC与乳糖及非脂固形物含量呈极显著负相关(P<0.01)。因此,奶水牛乳中SCC不仅与乳糖和非脂固形物含量密切相关,也提示其与奶水牛产后营养代谢状况有关。     

水牛奶和乳牛奶常规乳成分及乳脂脂肪酸组成的初步比较研究

采集广西地区当地3个不同品种水牛,测定乳成分及乳脂脂肪酸组成含量,并与相近胎次、相近泌乳月的本地荷斯坦奶牛、西门塔尔牛、娟姗牛进行比较。结果:3个品种水牛奶乳脂率、乳蛋白含量、总固形物百分含量和乳糖百分含量极显著高于荷斯坦牛奶、西门塔尔牛奶和娟姗牛奶(P<0.01)。3个品种水牛奶乳脂率、乳蛋白含量和总固形物百分含量相比,杂交水牛高于其他2个纯种河流型水牛尼里-拉菲和摩拉。以每100 g牛奶中含有的脂肪酸量来计,3个品种泌乳水牛奶中的各种脂肪酸含量的极显著高于荷斯坦奶牛、西门塔尔牛和娟姗牛(P<0.01)。3个品种泌乳水牛奶中的共轭亚油酸(CLA)、二十碳五烯酸(EPA)含量极显著高于荷斯坦奶牛、西门塔尔牛和娟姗牛(P<0.01)。     

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。     

三号HLJ型牛奶样品防腐剂的研制

为给鲜奶质检部门研制一个较理想的奶样防腐剂,经几十次试验,研制成了三号ＨＬＪ型牛奶样品防腐剂。它能使牛奶样品在３０℃下保存２８ｈ不变质,且对乳脂率、酸度、密度和异常乳检验无影响。     

浅谈牛奶产量和品质与粗饲料的关系

牛奶富有营养价值,其成分可分为水和固形物两部分,固形物包括乳蛋白、乳脂肪、乳糖、矿物质、维生素等多种物质。固形物含量多少直接影响乳的品质,乳脂率是衡量乳质     

影响西农萨能奶山羊产奶性状的非遗传因素分析

本试验旨在探究母羊出生年度、季节、胎次、泌乳阶段4个固定效应对西农萨能奶山羊产奶性状的影响。以西北农林科技大学萨能羊原种场2006-2018年的645只泌乳母羊为研究对象,每月采集乳样1次,采样日早、晚各采集1次,将两次乳样等比例混合后,采用乳成分分析仪测定乳脂率、乳蛋白率、乳糖率、总脂固形物、非脂固形物、密度、冰点和酸度共8个指标,结合羊场产奶量记录,采用固定效应模型,通过SAS 9.4软件进行表型的描述性统计分析,再采用GLM模型进行固定效应对产奶性状的影响分析。结果表明,西农萨能奶山羊平均300 d产奶量为507.67 kg,乳脂率为3.58%,乳蛋白率为3.20%,乳糖率为4.19%;总固形物含量为12.21%,非脂固形物含量为8.46%;出生年度、胎次对产奶量影响极显著（P<0.01）,出生季节对产奶量影响不显著（P>0.05）;泌乳阶段、出生年度对乳脂率等8个乳成分性状均有极显著影响（P<0.01）,胎次对除乳蛋白率和总固形物的其他6个乳成分指标均存在极显著影响（P<0.01）。综合以上试验结果,胎次及泌乳阶段是影响西农萨能奶山羊产奶性状的两种主要非遗传因素,第3、4胎母羊产奶性能最佳,泌乳早期的乳品质更优,揭示了对种群进行良种选育工作和羊饲养管理的重要性,也为后期进行奶山羊经济性状遗传评估和群体遗传改良提供理论基础。     

Comparison of the effectiveness of Milkofix, a preservative preparation, with traditional preservative agents in the determination of somatic cell count in milk samples using a fluoro-optic-electronic method]

Milkofix (M), a health friendly preservative substance, to be used for milk sample preservation (Trzicky, 1990), was compared with other preservatives. Untreated milk samples (N) were tested against samples treated with sodium azide (A; 0.0085 g NaN3 and 0.0630 g NaCl), bronopol (B; 0.0100 g bronopol and 0.090 g NaCl), potassium dichromate (C; 0.0330 g K2Cr2O7 and 0.0670 g KCl) and Milkofix (M; 0.1250 g). The doses of the preservatives A, B, C and M are per 25 ml milk. The somatic cell counts (SB) were determined on a FOSSOMATIC 90 apparatus (FOSS ELECTRIC, DENMARK). In the treated milk samples taken from individual cows the values of SB counts were significantly higher than in N samples if determined within eight hours after sampling (Tab. I): in A higher by 18.6%, B by 26.3%, C by 26.4% and M by 24.3% (P less than 0.05). The significantly higher values of SB counts were recorded in bulk milk samples treated with preservatives in comparison with N samples immediately after sampling: in A by 6.0%, in B, C and M by 12.9% (P less than 0.01; Tab. II). After one-day storage of N samples at a temperature of 4 degrees C these differences are insignificant (P greater than 0.05), thus the results of N, A, B, C and M samples obtained after one-day storage at 4 degrees C can be taken as actual and mutually comparable.(ABSTRACT TRUNCATED AT 250 WORDS)     

生鲜乳中林可霉素、四环素、土霉素和多西环素在不同储存条件下的稳定性研究

本研究旨在通过检测不同储存条件下林可霉素（LIN）、四环素（TET）、土霉素（TER）和多西环素（DOX）的残留量分析其在生鲜乳中的储存稳定性,包括储存温度和时间,复温温度、冻融次数和添加防腐剂等。试验结果显示,生鲜乳中LIN、TET、TER和DOX在相同的储存温度条件下,储存时间越长,稳定性越低;在相同的储存时间条件下,储存温度越高,稳定性越低;复温温度对这四种抗生素稳定性影响不显著;冻融次数越多,稳定性越低;LIN在添加防腐剂条件下稳定性较好;TET在添加重铬酸钾和甲醛条件下稳定性较差;TER和DOX在添加硫氰酸钠、叠氮钠、重铬酸钾、溴硝丙二醇和甲醛条件下稳定性均较差。本研究探讨了牛奶安全监测工作中LIN、TET、TER和DOX的最佳储存条件,为确保监测结果的准确性提供理论依据。     

添加不同防霉剂对全混合日粮存放的影响

选择山梨酸钾、脱氢醋酸钠、苯甲酸钠、丙酸和丙酸钙5种防霉剂,分别以0.15％和0.3％的剂量添加到奶牛全混合日粮（total mixed ration,TMR）中进行7 d的贮存试验,测定防霉剂对TMR饲料贮存效果的影响。试验结果表明,添加脱氢醋酸钠和0.3％山梨酸钾组的TMR饲料在贮存期内没有发热产生,也未发生霉变,其它各防霉剂添加组从贮存第2天开始逐渐出现升温发霉现象。贮存第2天,添加丙酸、丙酸钙及0.15％苯甲酸钠组TMR饲料的含水量极显著低于对照组（P＜0.01）;贮存第3天和第5天,添加脱氢醋酸钠和添加0.3％山梨酸钾组TMR饲料的含水量高于对照组（P＜0.05）。贮存过程中TMR饲料的粗蛋白质和粗脂肪均无明显变化。综合各项指标,TMR饲料中添加脱氢醋酸钠和山梨酸钾比苯甲酸钠、丙酸和丙酸钙有较好的防霉效果。     

Investigation on the inhibition of Campylobacter jejuni growth with the applications of some preservatives,medicines, herbs and herb preparations

The aim of this study was to determine the influence of chosen preservatives, medicines, herbs and herb preparations on 39 Campylobacter jejuni strains, which were isolated from fresh poultry carcasses. De-Nol and ventrisol were used in the original concentration. Propolis, propolan, artecholin and aukalen were of pharmacies origin. The rest of substances examined were 10% water solutions. Out of 11 substances examined, potassium sorbate, sodium benzoate, De-Nol and ventrisol exerted the strongest inhibitory action on Campylobacter jejuni.     

Testing Milkofix, a new preservative preparation for milk samples used for infrared analysis of milk components. II. Verification of its preservative effects in relation to infrared analysis]

For the purposes of the infrared analysis of the basic milk composition, Milkofix, an ecologically friendly preparation used for milk sample preservation (Trzicky, 1990), was compared with untreated samples (N) and with samples preserved with sodium azide (A), bronopol (B) and potassium dichromate (C) at a storage temperature of 20 degrees C (I) and 4 degrees C (II) in samples kept for 14 and 18 days. Pursuant to the recommendations cited in literature, the preservatives had these concentrations: A = 0.0085 g NaN3 and 0.0630 g NaCl; B = 0.0050 g bronopol and 0.0500 g NaCl; C = 0.0330 g K2Cr2O7 and 0.0670 g KCl; M = 0.1250 g, all amounts are per 25 ml milk. Three bulk milk samples were used which were analyzed on an automatic Milko-Scan 133 B infraanalyzer (Foss Electric, Denmark) every day. On the basis of a graphical evaluation of the results by IDF recommendations (1985) the times within which the applicable results could be obtained were determined for the various methods of milk sample treatment (Figs. 1 to 6): N I--0 days; A I--9; B I--10; C I--13; M I--4; N II--10; A II--5; B II--11; C II--15; M II--10 (Tab. I). The results recorded for Milkofix are in agreement with the conclusions drawn in the previous study, where the intervals of four and nine days were determined. The days to milk sample coagulation were as follows: N I--1 day, M I--10 days. The coagulation in A I, B I, C I and N II samples was not observed even after 13-day storage and in A II, B II, C II and M II samples not even after 17 days of storage. The results for particular components (fat, proteins, lactose) of milk samples differently treated in time are presented in Tabs. II, III and IV. A system of evaluating criteria (Tab. V) was used to determine the order beginning from the most convenient method of milk sample treatment for the given purpose: 1. C II, 2. C I, 3. B II and A I, 4. B I, 5. M II, 6. N II, 7. A II, 8. M I and 9. N I.(ABSTRACT TRUNCATED AT 400 WORDS)     

Correlation of Different Biochemical Parameters in Blood Sera of Healthy and Sick Cows

Metabolic diseases of cows represent the leading internal pathology in Lithuania in terms of incidence and economic impact. This paper summarizes the mineral metabolic state of milk cows, and details the influence of feeding on serum levels of calcium, nonorganic phosphorus, magnesium, potassium, sodium, glucose, total protein, and urea quantity, and correlationd among them, in healthy dry or post-calving cows as well as in cows with osteomalacia and milk fever after calving. There was less pronounced hypocalcaemia and there were only minor changes in phosphorus, magnesium, potassium and sodium in the serum of healthy dry and post-calving cows that had silage and mineral-vitamin supplements, compared to cows that did not have supplements and silage. There was a fall in calcium and phosphorus (to 1.89 +/- 0.12 mmol/L and 0.71 +/- 0.06 mmol/L, respectively) in the blood of cows sick with milk fever after calving, while levels of magnesium and potassium were increased. The correlation between calcium and phosphorus was r = 0.6993, p < 0.001 in the serum of sick cows. There was a fall in calcium, phosphorus and magnesium (to 1.86 +/- 0.46 mmol/L, 0.75 +/- 0.37 mmol/L, and 0.60 +/- 0.19 mmol/L, respectively) and an increase in sodium level (to 158.90 +/- 19.30 mmol/L) in the blood of cows with osteomalacia in comparison with healthy cows.     

丙酸钙对泌乳早期奶牛泌乳性能和代谢产物的影响

选用32头经产奶牛,根据泌乳期、上个泌乳期305 d产奶量和预产期,采用随机区组设计分为4组,对照组饲喂基础日粮,处理1、2、3组分别在基础日粮基础上添加丙酸钙100、200、300 g/d.结果显示,日粮添加丙酸钙对奶牛的采食量、乳脂率、乳蛋白率、乳糖率和乳干物质率无显著影响,200、300 g/d组产奶量和饲料转化效率显著高于对照组(P<0.05).200、300 g/d组血浆葡萄糖和胰岛素浓度显著高于对照组(P<0.05),而血浆游离脂肪酸和β-羟丁酸浓度显著低于对照组(P<0.05);200、300 g/d组尿酮浓度显著低于对照组和100 g/d组(P<0.05).试验结果表明,丙酸钙适宜添加量为200 g/d.     

酵母培养物益康XP对奶牛血浆内毒素含量及其它指标影响的研究

选取泌乳初期(泌乳天数<40d)健康奶牛12头,按胎次、泌乳天数和产奶量相同或相似的原则进行配对,分为试验组和对照组。两组日粮组成相同,但试验组牛每天添加益康XP(剂量为试验第1-7d500g/头/d,从第8d后减少到120g/头/d,分两次饲喂)。试验期为60d。于试验前1d、试验第20d、40d、60d分别采血,用鲎试剂法测定血浆内毒素含量;定期测定日均产奶量、乳脂率、乳蛋白率和体细胞数;并记录情期受胎率及疾病发生情况。结果表明:试验组奶牛在试验后第20d、40d、60d血浆内毒素均极显著低于对照组(p<0.01);产奶量在第20d、60d显著高于对照组(p<0.05);两组奶牛乳脂率、乳蛋白率、体细胞数差异均不显著(p>0.05);试验组情期受胎率极显著高于对照组(p<0.01);在疾病发生率方面,试验组极显著低于对照组(p<0.01)。     

丙酸镁对泌乳早期奶牛体况、泌乳性能和代谢参数的影响

选用36头经产奶牛,根据泌乳期、上一泌乳期305 d产奶量和预产期,采用随机区组设计分为4组,对照组饲喂基础日粮,处理1,2和3组分别在基础日粮基础上添加丙酸镁50,100和150 g/d,研究丙酸镁对泌乳早期奶牛采食量、泌乳性能、血液代谢参数和尿酮浓度的影响。结果表明,添加丙酸镁对奶牛的采食量、乳脂率、乳蛋白率、乳糖率和乳干物质率无显著影响,添加丙酸镁100和150 g/d对产乳量、饲料转化效率、体况及代谢参数有改善,该二处理组产奶量、饲料转化效率、体况评分、能量平衡、血浆葡萄糖和胰岛素浓度均显著高于对照组(P<0.05),而血浆游离脂肪酸和β-羟丁酸浓度显著低于对照组(P<0.05),尿酮浓度(除100 g/d组产后7 d测定值与50 g/d组无显著差异外)显著低于对照组和50 g/d组(P<0.05)。根据试验结果,丙酸镁适宜添加量为100 g/d。     

Effects of supplementing fish oil in the drinking water of dairy cows on production performance and milk fatty acid composition

The objective of this study was to determine the effects of supplementing fish oil (FO) in the drinking water of dairy cows on production performance and milk fatty acid composition. Sixteen multiparous Holstein dairy cows (741 +/- 84 kg of BW; 60 +/- 2.3 d in milk, mean +/- SD) housed in a tie-stall facility were used in the study. The study was conducted as a completely randomized design with repeated measurements. The cows were blocked by days in milk and allocated to 1 of 2 treatments: 10 g of menhaden FO/kg of DM top-dressed on the total mixed ration (FOT), and 2 g of menhaden FO/L delivered in the drinking water (FOW). The trial lasted for 5 wk: a 1-wk pretreatment adjustment period and 4 wk of treatment. The animals were fed and milked twice daily (feeding at 0830 and 1300; milking at 0500 and 1500) and had unlimited access to water. Dry matter intake (21.3 kg/d for FOT vs. 22.7 +/- 0.74 kg/d for FOW), milk yield (38.2 kg/d for FOT vs. 39.5 +/- 1.9 kg/d for FOW), and water intake (101 L/d for FOT vs. 107 +/- 4.4 L/d for FOW) were not affected by treatment. The mode of delivery of FO had no effect on milk fat percentage, but milk fat percentage declined linearly with time. The fatty acid contents of 7:0; 8:0; 9:0; 10:0; 12:0 in the milk of FOT cows were lower than for FOW cows, whereas 18:1 trans-12; 18:1 trans-13 and 14; 18:1 trans-16; and trans-9, trans-11 plus trans-10, trans-12 CLA were greater for FOT than for FOW. The contents of 24:1 in the milk of FOW cows were 48% greater than for FOT cows, although the concentrations were low in both groups. There was a tendency for the contents of 14:0 and 22:5n-6 to be greater in FOW cows than FOT cows and for the contents of iso-18:0 to be lower for FOW cows than for FOT cows. Although it appears that the amount of FO added in the study did not bypass the rumen as hypothesized, these results suggest that drinking water can be an alternative for supplementing FO to dairy cows without decreasing feed or water intake relative to cows fed FO in the diet.