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。     

影响荷斯坦奶牛受胎率的气候因子的分析

通过对广州市1982到1991年荷斯坦成年母牛6897头和青年母牛1508头的月均情期受胎率与同期的主要气候因子进行分析发现,温度是影响成年母牛受胎率的第一位因子,其直接作用大于间接作用。日照时数是仅次于温度和营养条件的第3位因子。相对湿度和风速直接作用较小。笔者提出的几个估计妊娠率的回归方程,可为牛奶生产者参考。     

血清酸滴定法对母牛进行早期妊娠诊断的研究

用血清酸滴定法对配种后16—45天的67头黑白花奶牛进行早期妊娠诊断的试验,取得了较为明显的结果,妊娠牛和空怀牛的符合率分别为95.65％和95.24％;总符合率为95.52％,与直检法比较、差异不显著(P>0.05)。     

激生系列苗促奶牛泌乳的试验初报

选产后2—3个月内未配种的中国荷斯坦牛20头，根据产奶水平、产犊日期和胎次均分两组．每组10头。试验组用生长抑素基因工程苗激生系列(1号、3号)免疫，对照组注射生理盐水。试验共观察75天，结果发现，试验组在免疫有效期内(免疫后14d-75a)，平均每头免疫奶牛增产0．81kg／d。     

Changes in plasma hormones profile and liver function in cows naturally exposed to lead and cadmium around different industrial areas

The present study was carried out to assess the endocrine status and liver function in adult cows reared in polluted environment around different industrial units in India.The effect on endocrine system was examined by determination of plasma level of thyroid hormones, thyroxin (T4) (n=269) and triidothyronin (T3) (n=269), stress hormone cortisol (n=266), and reproductive hormones such as estradiol (n=84) and progesterone (n=84) in cows (>3 years) reared around different polluted industrial and non-polluted areas.The respective blood lead and cadmium concentration was also determined in all the cows.The mean plasma levels of both T3 and T4 were significantly (P<0.05) higher around lead zinc smelter (2.43+/-0.26 and 41.1+/-2.9nmol/L) and closed lead cum operational zinc smelter (1.81+/-0.16 and 42.4+/-6.2nmol/L), where the mean blood lead level (0.86+/-0.06 and 0.51+/-0.09mug/ml) was also significantly higher than that of cows (0.07+/-0.01mug/ml) from unpolluted areas.Regression analysis of data from 269 cows revealed a significant (P<0.01) positive correlation between the blood lead and plasma T3 (r=0.287) and T4 (r=0.173).The correlation between thyroidal hormones and the blood cadmium concentration (r=-0.079 and -0.48; P>0.05) was not significant.Plasma cortisol level had also a non-significant (P>0.05) correlation (r=-0.092) with blood lead level.However, the mean cortisol level (4.02+/-1.96nmol/L) of cows in phosphate rock mining areas was significantly (P<0.05) higher than that of controls (1.98+/-0.70nmol/L). The mean plasma estradiol level was significantly (P<0.05) higher in cows around closed lead cum operational zinc smelter (47.1+/-19.5pg/ml) than that of the control animals (21.8+/-3.9pg/ml) and in rest of the areas, the difference did not reach the statistical significance (P>0.05).The serum biochemical analysis in 36 cows around lead-zinc smelter with the highest mean blood lead level (0.86+/-0.06mug/ml) amongst all the industrial/urban areas surveyed, and in 15 animals from non-polluted areas revealed a significant positive correlation between blood lead and serum ALT (alanine transaminase) (r=0.688, P<0.01) and AST (aspartate transaminase) (r=0.390, P<0.01) and a negative correlation with serum total lipids (r=-0.337, P<0.05), total protein (r=-0.449, P<0.01) and albumin(r=-0.662, P<0.01). It is concluded from the study that the natural exposure to lead in polluted environments disturbs the endocrine profile and the higher blood lead level alters serum biochemical parameters indicative of liver functions.     

The effect of Lameness before and during the breeding season on fertility in 10 pasture-based Irish dairy herds

Background

The effects of lameness on fertility have been documented frequently but few data are available from seasonally breeding, pasture-based herds (such as those used in Ireland) where cows are housed during the winter months but managed at pasture for the remainder of the year. This study determined the prevalence of lameness in a group of 786 cows in 10 pasture-based Irish dairy herds before, during and after the breeding season and assessed the relationship between lameness and the reproductive performance in these herds through serial locomotion scoring during the grazing period.

Results

Lameness prevalences of 11.6 % before, 14.6 % during and 11.6 % after the breeding season were found and these compared favourably to results from housed cattle and are similar to other studies carried out in grazing herds. A Cox proportional hazards model with locomotion score as time varying covariate was used. After controlling for the effect of farm, month of calving, body condition score at calving, body condition score loss after calving and economic breeding index, cows identified as lame during the study were less likely to become pregnant. Cows lame before the earliest serve date but no longer lame during the breeding season, cows becoming lame after the earliest serve date and cows identified lame both before and after this date were respectively 12 %, 35 % and 38 % less likely to become pregnant compared to cows never observed lame during the study. However, these findings were only significant for cows becoming lame after the earliest serve date and cows lame both before and after the start of breeding.

Conclusions

This study found that the reproductive efficiency was significantly (p < 0.05) lower in cows becoming lame during the breeding season and cows lame before and during the breeding season compared to non-lame cows. Cows no longer lame during the breeding season had a lower Submission Rate to first serve within 3 weeks of earliest serve date. However, the Pregnancy Rate was not significantly (p > 0.05) lower in these animals compared to cows never diagnosed as lame. In addition to lameness status, nutritional status and genetics were found to influence the reproductive performance in pasture-based Irish dairy herds.     

Development of a programmable piggyback syringe pump and four-times-a-day injection regimen for superovulation in non-lactating Holstein cows

The objectives of the present study were to develop a programmable piggyback syringe pump for bovine superovulation and to evaluate the effects of a four-times-a-day injection regimen using the pump. Non-lactating Holstein cows were treated with a total of 30 armour units of porcine FSH by injection four times a day with the pump (study, n = 9) or injection twice a day manually (control, n = 9) for four consecutive days from D10 of the estrous cycle. The pump-driven program successfully induced superovulation in all cows tested. The numbers of small (3– < 5 mm in diameter) and large (≥ 10 mm in diameter) follicles were greater in the study group on D11-13 and D14, respectively. There were fewer unovulated follicles detected on D21 (7 days after estrus) in the study group than in the control group (1.2 ± 0.4 and 3.2 ± 0.6, respectively).     

瘤胃保护性胆碱对奶牛的作用

本文简单介绍了胆碱的生化功能及其在瘤胃中代谢特性,并对瘤胃保护性胆碱在围产期奶牛生产上的应用及研究进展进行综述。     

LAMP法在牛早期胚胎性别鉴定中的应用

对LAMP试剂盒的准确性、特异性和灵敏度进行鉴定,同时对11枚体外胚胎和38枚体内胚胎进行性别鉴定。结果表明:血样DNA的鉴定结果与实际性别吻合;LAMP试剂盒的灵敏度很高,且只对牛有特异性;对胚胎样品的鉴定结果与实际性别吻合。     

河南孟津地区6种引起奶牛流产病原的PCR检测及分析

为调查孟津地区引起奶牛流产的主要病原,本实验采集该地区8个规模化奶牛养殖场共52头新鲜流产胎牛,及其母体的血液、阴道分泌物和鼻腔分泌物。对所采集样本进行新孢子虫（N.caninum）、弓形虫(T.gondii)、胎儿三毛滴虫(T. foetus)、布氏杆菌(B.abortus)、牛传染性鼻气管炎病毒（IBRV）和牛病毒性腹泻病毒（BVDV）6种常见流产病原的PCR和RT-PCR检测。结果显示,被检样本总感染率为44.2%（23/52）,其中新孢子虫感染率最高,为32.7%（17/52）;IBRV次之,为13.5%（7/52）;胎儿三毛滴虫、布氏杆菌、弓形虫和BVDV感染率分别为1.9%、1.9%、1.9%和0。11.5%（6/52）的被检样本存在混合感染,其中以新孢子虫+IBRV混合感染为主（50%,3/6）。结合被检流产奶牛的临床特征及饲养管理等因素,推断新孢子虫是导致该地区奶牛流产的主要病原。