壳聚糖对乳房炎奶牛血清自由基代谢的影响

目的:探讨壳聚糖对乳房炎奶牛血清自由基代谢的影响。方法:选择产奶量、胎次和泌乳期相近,营养中等,乳房炎阴性6头,阳性30头,组成0(阴性对照组)、1(阳性对照组)和2、3、4、5组(试验组),每组6头。各组基础日粮相同。分别在各组基础日粮中添加壳聚糖0、0、10、20、40和80g/d·头。连续饲喂2周。分别于试验前(0周)、1周和2周采取血样,分离血清,测定血清SOD、CAT、GSH-Px活力和MDA、NO的含量。结果:饲喂壳聚糖后,各组血清SOD与GSH-Px活力显著升高,血清MDA含量显著降低。各试验组奶牛血清CAT活力均有升高的趋势,血清NO含量有降低的趋势,但差异均不显著(P>0·05)。结论:壳聚糖具有提高乳房炎奶牛血清SOD和GSH-Px活力,降低血清MDA的含量,提高机体抗氧化能力,改善血清自由基代谢水平和促进炎症康复的作用。但对血清CAT和NO基本没有影响。     

我国部分地区奶牛乳房炎的病因及发病情况调查

１９８０～１９８９年对２２个城市３２个奶牛场１０３７１头成年泌乳牛进行乳房炎病因及发病情况调查，并对其中３３８４头泌乳期奶牛的１２６６０个乳区进行隐性乳为检查，结果临床型乳房炎奶牛发病率为３３．４１％，隐性乳房炎奶牛头阳性检出率为７３．９１％，乳区阳性检出率为４４．７４％，采集２０１５份患乳房炎和健康奶牛奶样进行细菌性检查，临床乳房炎，隐性乳房炎和健康奶样病原菌检出率分别为８５．３７％，６２．７６     

生化黄腐酸制剂防治奶牛隐性乳房炎试验

用LMT诊断液对兰州市城关区五泉奶牛场泌乳期高产群的62头奶牛进行隐性乳房炎检测,将检出的阳性牛体细胞较高的牛分为高剂量组,其余牛随机分为低剂量组和对照组,各组使用生化黄腐酸制剂-牛乐先锋,每日一次添加到奶牛(全混合)日粮中,高剂量组每天250g/头;低剂量组每天100g/头;对照组不添加。结果表明,牛乐先锋高、低剂量组奶牛隐性乳房炎阳性牛和阳性乳区转阴率分别达到87.50%、86.36%和75.00%、66.67%,均显著高于对照组(12.5%和7.14%,P<0.05)。试验表明,生化黄腐酸(牛乐先锋)对防治奶牛隐性乳房炎、降低体细胞数具有显著的效果。     

奶牛隐性乳房炎对产奶量、乳成分和奶中物理指标的影响

为了研究奶牛隐性乳房炎对产奶量、乳常规成分、乳密度和冰点的影响 ,对哈尔滨市及周边地区的 2 89头中国荷斯坦奶牛进行了调查 ,对其中 5 1头患隐性乳房炎奶牛和 2 5头健康奶牛的乳常规成分、乳密度和乳冰点进行了测定。结果表明 :调查地区的奶牛隐性乳房炎阳性率为 75 %。隐性乳房炎导致产奶量下降 ,平均减少 2 .75kg/d ;乳脂肪含量显著低于健康奶牛 (P <0 .0 5 ) ;总酪蛋白和乳糖含量极显著低于健康奶牛 (P <0 .0 1) ;而乳干物质、总蛋白质、非脂固形物的含量及乳密度、乳冰点与健康奶牛无显著差异 (P >0 .0 5 )。     

中药透皮剂对隐性乳房炎奶牛泌乳量、白细胞及乳腺局部免疫的影响

为开发安全、有效、稳定的新型中兽药制剂,有利于奶牛隐性乳房炎的防治,试验研究了中药透皮剂对隐性乳房炎奶牛泌乳量、白细胞、白蛋白（ALB）、丙氨酸氨基转移酶（ALT）、乳酸脱氢酶（LDH）的影响。方法：记录用药前后5d日泌乳量,分别采用试剂盒和CA-500血液分析仪测定用药前后乳汁中ALB、ALT、LDH和血液中白细胞。结果：患隐性乳房炎奶牛泌乳量显著降低（P〈0．05）,血液中WBC、MON、GRA、LYM％显著高于健康牛（P〈0．05）,而乳汁中的ALB、ALT和LDH含量极显著高于健康奶牛（P〈0．01）。通过5d中药透皮剂治疗后,奶牛产奶量大幅度增加,WBC、MON、GRA、LYM％、ALB、ALT和LDH与健康牛比差异不显著（P〉0．05）。结论：中药透皮剂对奶牛隐性乳房炎具有良好的治疗效果。     

乳酸菌微生态制剂防治奶牛隐性乳房炎应用研究

本研究以不同牧场中的荷斯坦奶牛为研究对象,以100~200g/(头·d)的剂量添加干酪乳杆菌HM-09和植物乳杆菌HM-10及其代谢产物的复合乳酸菌微生态制剂(有效活菌数≥1.5×109 cfu/g),应用牛场DHI数据中的乳体细胞数(SCC)数据对试验牛只进行隐性乳房炎分析,研究其对奶牛隐性乳房炎的防治效果,结果显示:饲喂5~10d乳酸菌微生态制剂后,奶牛平均体细胞数显著降低23.8%~62.8%。结果表明,本试验所用复合乳酸菌微生态制剂可应用于奶牛隐性乳房炎的防治。     

用CMT法对奶牛隐形乳房炎检测及治疗分析

用CMT法(加州乳房炎测试法)对安次区某牛场的泌乳牛群中的50头牛的200个乳区进行隐性乳房炎检测。结果为奶牛隐性乳房炎阳性率为72%,强阳性5%。对其10头检测为强阳性的牛投服盐酸左旋咪唑,加强饲养管理,一周后对给药的10头牛再次进行检验,乳区隐性乳房炎阳性率由45%下降为37%,乳区隐性乳房炎强阳性率由原来的27.5%下降到10%,结果证明盐酸左旋咪唑对隐性乳房炎的治疗效果明显。     

重庆部分地区泌乳奶牛乳房炎的病因及发病情况调查

对重庆部分地区６个奶牛场１１８头泌乳奶牛进行临床型乳房炎的病因及发病情况调查,并对其中７６头泌４乳奶牛进行隐性乳房炎检查。同时对２２６份患乳房炎和健康奶牛奶样进行细菌学分离鉴定,结果表明：临床型乳房炎奶牛及阳性乳区分别为８．４７％（１０／１１８）和３．３２％（１５／４５２）;隐性乳房炎奶牛及阳性乳区分别为７８．９４％（６０／７６）和５０．３４％（１４８／２９４）;临床型乳房炎、隐性乳房炎奶牛的阳性     

冀东地区奶牛隐性乳房炎病原菌的分离鉴定

通过LMT法、乳汁pH检验法和体细胞直接计数等方法相结合,对冀东地区3个大型奶牛场、8个奶牛养殖户选取的1 021头奶牛进行隐性乳房炎流行病学调查与病菌分离鉴定。结果表明,隐性乳房炎发病率为60.63%(619/1021),乳房炎阳性乳样品中细菌分离率达88.21%(546/619)。从543头隐性乳房炎患牛的阳性乳区乳样中分得细菌共4类14种菌82株,其中葡萄球菌36株,占43.90%;链球菌33株,占40.24%;肠杆菌类8株,占9.76%;棒状杆菌5株,占6.10%。冀东地区奶牛隐性乳房炎主要病原菌为金黄色葡萄球菌和无乳链球菌。     

中兽药在治疗奶牛几种常见病的应用

一、奶牛乳房炎 奶牛乳房炎是危害奶牛养殖业最常见的疾病之一.全世界约有2.2亿头奶牛,其中约1/3奶牛患各种类型的乳房炎.据报道,美国每年因奶牛乳房炎造成的损失达20亿美元,而我国奶牛乳房炎的发病率则高于世界平均水平.有资料报道:某牛场临床型乳房炎及阳性乳区分别为8.47％和3.32％;隐性乳房炎及阳性乳区分别为78.94％和50.34％;临床型乳房炎、隐性乳房炎的阳性乳区奶样和健康奶牛的奶样细菌检出率分别为86.67％、87.83％和73.00％;检出的细菌主要是葡萄球菌和链球菌.奶牛乳房炎造成的损失约70％是由隐性乳房炎引起的产奶量下降,我国每年因隐性乳房炎造成的损失约达1.35亿元人民币.     

Norfloxacin pharmacokinetics in lactating cows with sub-clinical and clinical mastitis

Single-dose pharmacokinetics of norfloxacin after intravenous administration of norfloxacin nicotinate at 10 mg norfloxacin/kg body weight was investigated in cows with healthy udders and in cows with chronic subclinical and postacute clinical mastitis. An HPLC method was used to determine the norfloxacin concentrations in serum and milk. Significant differences were observed in norfloxacin pharmacokinetics when administered to cows with infected udder quarters. The clearance (Cl) values were 10.4+/-2.5, 13.2+/-1.9 and 14.2+/-2.1 mL/min/kg (mean +/-SD) in the control (healthy udder) cows and in cows with subclinical and postacute clinical mastitis, respectively. There appeared to be a trend of increasing clearance according to severity of the disease. The volume of distribution at steady state (Vss) in the respective groups was 3.1+/-0.7, 2.2+/-0.6 and 1.3+/-0.2 L/kg. The volume of distribution was significantly decreased in the cows with postacute clinical mastitis. The half-lives (t1/2) and mean residence times (MRT) of norfloxacin were 353, 206 and 115 min (harmonic means) and 306+/-76, 168+/-39 and 95+/-9 min in control cows or in cows with subclinical and postacute clinical mastitis, respectively. The half-lives in the clinical mastitis group were significantly shorter than in the control group and the mean residence times were significantly shorter in the two mastitis groups when compared to the control group. Norfloxacin concentrations in milk were extremely high when compared to the respective serum concentrations. The area under the concentration vs. time curve (AUC) of norfloxacin in milk was 23899+/-6206 mg/L x min in the control cow group. The AUC in milk was significantly lower in the infected udder quarters of the mastitis groups (5075+/-1887 mg/L x min and 7484+/-4645 mg/L x min in the subclinical and the clinical group). The AUC values were significantly lower in milk from the infected udder quarters of the cows with chronic subclinical and postacute clinical mastitis when compared to the values in milk from the healthy quarters of the same udder. Norfloxacin was marginally bound to serum protein. The binding was concentration dependent and was 19, 13 and 6% at 0.2, 1.0 and 8.4 mg/L, respectively. Binding to milk protein was 46-51% and concentration independent. An in vitro dialysis model was used to simulate drug transport between serum and milk as a function of protein binding. The results showed that the rate of norfloxacin disposition from milk to serum was slower than from serum to milk, which was in agreement with the findings obtained in the pharmacokinetic study. Norfloxacin was poorly soluble in organic solvents and our results suggest that changes in the degree of ionization of the drug in different body fluids considerably affect its disposition.     

Effect of intramammary infusion of rbGM-CSF on SCC and expression of polymorphonuclear neutrophil adhesion molecules in subclinical mastitis cows

The effect of rbGM-CSF intramammary infusion on the subclinical mastitis was evaluated by the somatic cell count (SCC) and expression of adhesion molecules (CD62L and CD11b) on the surface of neutrophils (PMN) in blood and milk. Fifteen cows diagnosed to have subclinical mastitis were used in this study. Seven cows showed a decrease in the SCC (decreased group), whereas 8 cows showed an increase in the SCC (increased group) 7 days after infusion of rbGM-CSF compared to pre infusion level. The percentage of CD62+ cells tended to be lower and CD11b+cells tended to be higher at 6 h on blood PMN in the decreased group of cows. Increased group of cows showed opposite tendencies. The mean fluorescent intensity of these adhesion molecules expressed on PMN in blood and milk was similar in both groups. These results suggested some association between expression of adhesion molecules and changes in SCC by rbGM-CSF. Responsiveness of PMN adhesion molecules to rbGM-CSF might determine the changes in SCC of the subclinical mastitic cows after infusion of rbGM-CSF.     

Effects of bovine lactoferrin by the intramammary infusion in cows with staphylococcal mastitis during the early non-lactating period

To evaluate the clinical effects of bovine lactoferrin on staphylococcal mastitis in Holstein cows during the early non-lactating period, 41 mammary quarters were selected randomly from 36 cows on 3 dairy farms. Twelve quarters were infused intramammarily with bovine lactoferrin. Twenty-nine quarters were infused with antibiotic as a control. In the bovine lactoferrin-infused group, 91.7% of mastitic quarters were cured at 7 days after calving, compared with 48.3% in the control group. Furthermore, the changes in mammary secretion induced by the infusion of bovine lactoferrin were investigated. Mean numbers of staphylococci in mammary gland secretions were significantly decreased in both 5 bovine lactoferrin-infused quarters and 5 antibiotic-infused control quarters (p<0.05). Unlike in the control quarters, the mean total cell concentration in the mammary gland secretions increased in bovine lactoferrin-infused quarters. Similar results were obtained in 6 healthy quarters which were infused with bovine lactoferrin. In these quarters, the cell population contained mainly phagocytes such as polymorphonuclear leukocytes and cells positive for CD11b which is known as a complement receptor. The mean concentration of C3 in mammary gland secretions was significantly increased in 5 mastitic quarters infused with bovine lactoferrin (p<0.05), but showed no significant change in 5 mastitic control quarters. These results suggested that bovine lactoferrin treatment for staphylococcal mastitis in the early non-lactating period might increase the rate of cure through the induction of innate immunity in the host.     

Local and systemic effects of endotoxin mastitis on the chemiluminescence of milk and blood neutrophils in dairy cows

The local and systemic effects of intramammary lipopolysaccharide (LPS) injection on the chemiluminescence (CL) of milk and blood polymorphonuclear leukocytes (PMN) were investigated in six healthy early lactation cows. Clinical signs of acute mastitis such as fever, increased heart rate and a decreased milk production were observed in all cows. Before LPS challenge, the CL activity of milk PMN was significantly lower than that of blood PMN (P < 0.01). A significant negative correlation was found between pre-challenge milk and blood PMN CL and, the decreased milk production in unchallenged quarters. The CL activity of milk PMN from LPS-injected quarters increased following LPS challenge, whereas it remained unchanged in control quarters. The CL activity of blood PMN showed a biphasic increase, with two peaks and a valley below pre-challenge CL activity (P < 0.01). At post-challenge hours (PCH) 6 and 12, the CL activity of milk PMN from LPS-injected quarters exceeded that of blood PMN (P < 0.05 and P < 0.001, respectively). The decreased CL activity of blood PMN and the enhanced CL activity of milk PMN during endotoxin-induced mastitis was reflected by changes in the shape of the CL curve. In blood PMN, a decrease of the second peak of the CL curve suggests that the myeloperoxidase (MPO)-H2O2 system is impaired during endotoxin-induced mastitis. In contrast, the MPO-H2O2 system was enhanced in milk PMN from challenged quarters. The highest duration and intensity of reactive oxygen intermediate (ROI) production was observed in milk PMN from LPS-injected quarters at PCH 12. The increased viability of PMN in LPS-injected quarters and to a lesser extent in control quarters suggests possible effects of both facilitated diapedesis and inflammatory mediators on milk PMN survival. In conclusion, our results suggest that a combination of local and systemic action of E. coli endotoxin is involved in the priming of milk PMN during mastitis.     

Effects of antibiotics on phagocyte recruitment, function, and morphology in the bovine mammary gland during the early nonlactating period

The effects of 2 antibiotic preparations administered intramammarily on phagocyte recruitment, function, and morphology were evaluated at the beginning of the nonlactating period. Twelve cows with no clinical or microbiologic evidence of mastitis were assigned to 1 of 2 treatment groups. At the end of lactation, 1 of the antibiotic preparations was infused in a fore- and hind quarter of each cow; the remaining quarters were untreated controls. One group was given benzathine cephapirin; the second group was given sodium novobiocin. Secretion samples were collected from 1 treated and 1 control quarter at 16 hours, and from the remaining 2 quarters at 64 hours after treatment. Total and differential somatic cell counts were determined, and morphology of mammary polymorphonuclear neutrophils (PMN) and macrophages was observed by transmission electron microscopy. In vitro ingestion and killing of Staphylococcus aureus by mammary PMN and macrophages were assessed by fluorescent microscopy, using acridine orange stain. Cells resident in a fixed volume of secretion were incubated with a known concentration of S aureus. Total cell and PMN concentrations were higher in treated than in control quarters. Neutrophils were the predominant cell type in both treated and control quarters over the sampling period. As measured in this study, in vitro ingestion and killing of S aureus by individual PMN from treated quarters was reduced. Antibiotic treatment also increased the proportion of morphologically abnormal phagocytes. There were significant correlations among PMN ingestion, killing, and morphology. However, increased PMN concentrations tended to compensate for the reduced phagocytic function of individual cells. Therefore, efficacy of antibiotic treatment of nonlactating cows may depend, at least in part, on increased PMN concentration, which may tend to compensate for reduced phagocytic function. Compared with PMN, macrophages appeared to have only a minor role in phagocytosis of bacteria.     

Effects of autogenous toxoid-bacterin in lactating cows with Staphylococcus aureus subclinical mastitis

To evaluate clinical effects of autogenous toxoid-bacterin treatment for Staphylococcus aureus subclinical mastitis in lactating cows, 22 cows which had at least one S. aureus infected quarter were selected from among cows at a S. aureus prevalent dairy farm. Eleven cows were injected with their own autogenous toxoid-bacterin and the others were maintained as non-injected control. In the toxoid-bacterin injected group, 27% of infected quarters were cured during the 12-week trial, compared to 5% in the control group. New intramammary infections with S. aureus were only detected in 3 quarters of the control group. Mean IgG antibody titer against S. aureus somatic antigens and alpha-toxin in serum and milk were significantly increased in the toxoid-bacterin injected group (p<0.05) and remained higher than those of the control group which showed no significant changes (p<0.05). In contrast to the control group, from 3 weeks after the second injection of the toxoid-bacterin injected group, mean S. aureus cfu/ml in milk samples from injected quarters with S. aureus was significantly decreased until the end of the study (p<0.05). In the toxoid-bacterin injected group, significant decreases of mean SCC were detected from milk samples from infected quarters with S. aureus from week 7 to week 10 (p<0.05). These data show that autogenous toxoid-bacterin treatment against S. aureus subclinical mastitis in lactating cows may increase the cure rate of the infections, reduce the severity of the infections and also prevent occurrence of the new infections.     

THE NEW SOUTH WALES MASTITIS CONTROL PROGRAM

SUMMARY A mastitis control program based on teat dipping and dry cow therapy was evaluated in 35 herds over a 3 year period. The incidence of subclinical mastitis as detected by the Rapid Mastitis Test (RMT) fell from 34% to 12% quarters positive, a reduction of 65%. Clinical mastitis was reduced from 37 clinical cases per 100 cows in the first 3 month period to 12 clinical cases per 100 cows in the last 3 month period, a reduction of 68%. Variations in response to the program in the reduction of subclinical and clinical mastitis are discussed and the results compared with similar trials conducted overseas. The Modified Whiteside Test was used on bulk milk samples from the control herds and these results were significantly correlated with the prevalence of subclinical mastitis assessed by RMT individual quarters.     

宁波市奶牛乳房炎发病及综合防治试验研究

为了解宁波地区奶牛乳房炎发病及主要病原菌构成,采用乳房炎诊断试剂(HMT)对宁波市8个奶牛场307头泌乳牛的1249个乳区进行了隐性乳房炎流行情况调查,采集HMT反应阳性(++)及强阳性(+++)乳区奶样进行细菌分离与鉴定;用纸片扩散法检测主要病原菌对常用抗菌药物敏感性,并选择具代表性牧场进行乳房炎综合防治试验。结果显示,宁波市奶牛隐性乳房炎的头阳性率为71.3%,乳区阳性率为33.5%。主要病原菌的检出率依次为:凝固酶阴性葡萄球菌47.1%、无乳链球菌20.4%、停乳链球菌17.3%、金黄色葡萄球菌5.1%和乳房链球菌3.9%。主要病原菌对青霉素、氨苄青霉素、庆大霉素、复方新诺明和链霉素等药物有不同程度的耐药性,对头孢类及苯唑青霉素敏感。综合防治措施的实施可以明显降低桶奶总细菌数,改善牛奶品质。     

Simultaneous intramammary and intranasal inoculation of lactating cows with bovine herpesvirus 4 induce subclinical mastitis

In this study, we examined whether an experimental bovine herpesvirus 4 (BHV4) infection can induce bovine mastitis, or can enhance bovine mastitis induced by Streptococcus uberis (S. uberis). Four lactating cows were inoculated intramammarily and intranasally with BHV4, and four lactating control cows were mock-inoculated. After 14 days, two of four cows from each group were inoculated intramammarily with S. uberis. No clinical signs were recorded in cows inoculated only with BHV4, and their milk samples showed no abnormal morphology, despite the fact that BHV4 replicated in inoculated quarters. Somatic cell count increased significantly in milk from three of six BHV4-inoculated quarters, compared to the non-inoculated quarters of the same cows (within-cow) and the quarters of mock-inoculated cows (control group) on days 8, 9 and 11 post-inoculation (pi). BHV4 was isolated from nasal swabs between days 2 and 9 pi. Clinical mastitis was observed in all four cows intramammarily inoculated with S. uberis. A preceding BHV4 infection did not exacerbate the clinical mastitis induced by S. uberis. S. uberis infections appeared to trigger BHV4 replication. From one quarter of each of two cows inoculated with BHV4 and S. uberis, BHV4 was isolated, and not from quarters inoculated with BHV4 only. In conclusion, BHV4 did not induce bovine clinical mastitis after simultaneous intranasal and intramammary inoculation. However, the BHV4 infection did induce subclinical mastitis in 50% of the cows and the quarters.