乳制品进口对我国乳业发展的影响及有关政策建议.

乳制品进口对满足国内需求、促进我国乳业整体水平的提高和生产结构调整起到一定作用。受乳品质量安全事件频发、生鲜乳标准降低、国内需求不断增加和国际贸易环境的影响,近年来乳制品进口量增加,对我国奶牛养殖业形成压力,使众多乳制品企业出现生存危机,侵害了乳业广大生产者和消费者的利益。本文分析了乳制品进口对我国乳业影响,并提出了有关支持和保护我国乳业发展的政策建议。     

饮水温度对崂山奶山羊产奶性能的影响

为了研究在寒冷季节饮水温度对崂山奶山羊产奶量及主要乳成分的影响,给奶山羊饮用16、22、28℃的温水,以自然水温为对照,结果发现:奶山羊的饮水量和产奶量随水温升高而增加,从低到高其产奶量比CK组产奶量分别显著提高16.2%、18.4%、23.1%(P<0.05);随饮水温度升高,乳脂率和乳蛋白率整体呈现递减趋势,但22℃组高于16℃组和28℃组,建议在冬季寒冷季节给奶山羊饮用22℃温水为宜,既能保证产奶量又对乳品质影响较小。     

硒的生物学特性与奶牛营养需要的研究进展

对硒的生物学特性,硒对奶牛健康的影响以及奶牛对硒的需要量作了比较全面的综述,为奶牛饲养过程提供科学的参考依据。     

Seroprevalence of chlamydial infection in dairy cattle in Guangzhou, southern China

Chlamydia spp. are obligate intracellular gram-negative bacteria that cause a wide range of significant diseases in humans and animals worldwide, resulting in significant economic losses. Chlamydial infection in cattle has been reported in many countries including China. However, there has been no survey of chlamydial infection of dairy cattle in Guangzhou, southern China. The objective of the present investigation was to examine the chlamydial seroprevalence in dairy cattle in Guangzhou, subtropical southern China by using an indirect hemagglutination assay (IHA). The overall seroprevalence of chlamydial infection in dairy cattle was 7.25% (29/400). Greater than or equal to eight-yr-old dairy cattle had the highest seroprevalence (10.34%), followed by those that were ≥ 6 years old or < 7 years old dairy cattle (10.20%), although there were no statistically significant differences among different groups (P > 0.05). Dairy cattle with 5 pregnancies had the highest seroprevalence (10.81%). These results indicate that chlamydial infection was present in dairy cattle in Guangzhou, subtropical southern China, and integrated strategies and measures should be executed to control and prevent chlamydial infection and disease outbreak in the study region.     

纳米硒对岢岚绒山羊及胎儿的生物学效应

为研究纳米硒对岢岚绒山羊妊娠母羊及胎儿机体免疫力、抗氧化性和生长发育的影响,选择体重相近的岢岚妊娠绒山羊80只,随机分为2组,分别喂以基础日粮(C组)和添加0.5mg/kgDM纳米硒的饲粮(Se组),实验期110d。结果表明:妊娠期绒山羊日粮中添加硒后,血液中淋巴细胞、单核细胞、嗜中性粒细胞的百分比显著提高(p<0.05),异型淋巴细胞百分比显著降低(p<0.05),血清中血清球蛋白(GLO)、免疫球蛋白IgG和IgM显著提高(p<0.05);日粮中纳米硒的添加极显著(p<0.01)提高了母羊及胎儿血清中GSH-Px、SOD的活性,极显著(p<0.01)提高了母羊及胎儿肝、胎盘组织中GSH-Px、SOD的活性,极显著(p<0.01)降低了母羊及胎儿血清与胎盘组织中MDA的浓度;在日粮中添加纳米硒后,显著增加了胎盘、胎儿及胎儿肝、肾组织的重量(p<0.05)。结论:日粮中添加0.5mg/kgDM纳米硒,增强了妊娠母羊及胎儿机体免疫力和抗氧化能力,进一步促进了胎儿的生长发育。     

Physiopathological Effects of the Administration of Chronic Cyanide to Growing Goats – A Model for Ingestion of Cyanogenic Plants

Ingestion of cyanogenic plants, such as cassava and sorghum, has been associated with goitre and tropical pancreatic diabetes in both humans and animals. Thus, the objective of the present study was to determine the toxic effects on the thyroid and pancreas in growing goats of prolonged exposure to potassium cyanide (KCN). Thirty-four male goats were divided into five groups dosed with KCN at 0 (control), 0.3, 0.6, 1.2 or 3.0 mg/kg daily for 5 months. Blood samples were obtained in order to determine the glucose, cholesterol, thyroxine (T₄), triiodothyronine (T₃) and thiocyanate concentrations and for haematological studies; pancreas and thyroid gland were collected for histopathological study. The group receiving the highest dose of cyanide showed lower body weight gains and carcase weights and a decrease in plasma T₃ concentrations compared to the control group. Reabsorption vacuoles in follicular colloid and normocytic normochromic anaemia were observed in the experimental animals. Inhibition of peripheral conversion of T₄ to T₃ is suggested. However, no diabetogenic effects were observed.     

Pharmacokinetics of Enrofloxacin and Its Metabolite Ciprofloxacin after Intramuscular Administration of Enrofloxacin in Goats

The pharmacokinetics of enrofloxacin and its active metabolite ciprofloxacin were investigated in goats after a single intramuscular administration of enrofloxacin at 2.5 mg/kg body weight. The plasma concentrations of enrofloxacin and ciprofloxacin were determined simultaneously by a HPLC method. The peak concentrations (C _max) of enrofloxacin (1.13 g/ml) and ciprofloxacin (0.24 g/ml) were observed at 0.8 and 1.2 h, respectively. The elimination half-life (t _1/2), volume of distribution (V _d(area)), total body clearance (Cl_B) and mean residence time (MRT) of enrofloxacin were 0.74 h, 1.42 L/kg, 1329 ml/h per kg and 1.54 h, respectively. The t _1/2, area under the plasma concentration–time curve (AUC) and the MRT of ciprofloxacin were 1.38 h, 0.74 g h/ml and 2.73 h, respectively. The metabolic conversion of enrofloxacin to ciprofloxacin was appreciable (36%) and the sum of the plasma concentrations of enrofloxacin and ciprofloxacin was maintained at or above 0.1 g/ml for up to 4 h. Enrofloxacin appears to be useful for the treatment of goat diseases associated with pathogens sensitive to this drug.     

The impact of Theileria parva infections and other factors on calf mean daily weight gains in smallholder dairy farms in Murang'a District, Kenya

The association between mean daily weight gain, Theileria parva infections, clinical East Coast fever and other possible determinants of weight gain were examined in a longitudinal observational study that was conducted in cohorts of female calves from five agro-ecological zone (AEZ)-grazing strata. The strata were upper-midlands (UM) 1 zero-grazing, UM 1 open-grazing, UM 2 zero-grazing, UM 4 zero-grazing and UM 4 open-grazing. In total, 225 calves on 188 smallholder dairy farms were visited within the first 2 weeks of life and thereafter at biweekly intervals up to the age of 6 months between March 1995 and August 1996. During each visit, the calves were weighed and other calf-management practices in the farm during the visit such as housing, feeding and tick control also were recorded. Other events such as morbidity and mortality between or during the visits were also recorded.

The overall mean daily weight gains were 0.24–0.29 kg (S.D.=0.17–0.22 kg) and were lower than the recommended targets for smallholder farms of 0.40–0.50 kg. The major tendency in variability of daily weight gains was due to visit-to-visit variation (especially in calves >3 months old).

Differences in mean daily gains were associated with AEZ-grazing strata and calf-level factors that included breed of calf, calf sickness, incidence of ECF, feeding of milk, concentrate feeds and minerals and interaction between calf age and AEZ-grazing strata (P<0.05). ECF and other calf sicknesses exerted a temporal effect on calf-growth at the height of illness and immediately after; calves later recovered the lost growth except where other factors such as poor calf nutrition prevailed. Improvement in calf-growth in Murang’a District is achievable and extension services should continue to target individual-calf-level management practices.     

苦马豆素人工抗原免疫山羊的安全性试验

试验通过分析疯草毒素人工抗原(疫苗)SW BSA免疫山羊时对机体肝功、肾功的影响,进行安全性评价。将30只羊随机分为对照组(6只)、免疫A组(12只)、免疫B组(12只),免疫组依次进行基础免疫、首免、加强免疫,每次免疫前进行采血,分析血清中谷丙转氨酶(GPT)、谷草转氨酶(GOT)、尿素氮(BUN)、α苷露糖苷酶(AMA)、碱性磷酸酶(AKP)、乳酸脱氢酶(LDH)的变化,同时检测尿液中有无SW。结果表明,免疫组与对照组的血清GPT、GOT、BUN、AMA、AKP、LDH差异均不显著(P>0.05),尿液中未检查出SW。     

不同收获期玉米青贮DM和CP奶牛瘤胃降解率研究

结果表明：蜡熟期玉米青贮DM的有效降解率（60.07%）分别比乳熟期（52.91%）和乳熟前期（45.13%）高7.16个百分点（P＜0.05）和14.94个百分点（P＜0.01）;乳熟期玉米青贮DM的有效降解率比乳熟前期高7.78个百分点（P＜0.05）.蜡熟期玉米青贮CP的有效降解率（81.93%）分别比乳熟期（76.43%）和乳熟前期（73.36%）高5.50个百分点（P＜0.05）和8.57个百分点（P＜0.05）;乳熟期玉米青贮CP的有效降解率比乳熟前期高3.07个百分点，但差异不显著.