Effect of seasonal conditions on oestrus occurrence and postpartum period in Anatolian water buffaloes

Oestrus and calving records of Anatolian buffaloes were analyzed to investigate influence of climatic conditions on oestrus occurrence and postpartum period. Oestrus records showed a seasonal pattern concentrated between July and September which is the warmest period of the year. Likewise, more than half (52.7%) of the total calvings occurred between May and August. Month of calving significantly influenced the length of calving to first oestrus interval and open period (P < 0.01). The average length of open period was significantly shorter in autumn and summer calvers compared to those calved in spring and winter (P < 0.05) during long days. The humidity rate was negatively correlated with both calving to first oestrus interval and open period (P < 0.05). In conclusion, exposure to high environmental temperatures around 20 degrees C exerted no suppressive influence on ovarian activity in Anatolian buffaloes. Although humidity rate (P < 0.05) and ambient temperature (P < 0.01) was found to be correlated with the duration of postpartum period, day length might be the main factor regulating reproductive biorhythm and postpartum events in Anatolian buffalo cows.     

The afa-related gene cluster in necrotoxigenic and other Escherichia coli from animals belongs to the afa-8 variant

Six hundred and nine necrotoxigenic Escherichia coli type 1 and 2 (NTEC1 and NTEC2) and non-NTEC isolated in Western and Southern Europe, North Africa and Canada from diseased calves, pigs, humans, poultry, and 55 isolated from asymptomatic calves were studied for the identification of afa-related sequences to the recently described afa-7 and afa-8 gene cluster variants from two bovine Escherichia coli (Lalioui et al., 1999). Colony hybridization and PCR assays for the afaD-7, afaE-7, afaD-8 and afaE-8 identified the afa-related sequences to the afa-8 gene cluster in most (67/79; 85%) of the E. coli positive with the Afa-f family probe and in 14 additional strains negative with the Afa-f probe. No E. coli was positive for the afa-7 gene cluster. The existence of afa-8 positive strains was thus confirmed among bovine E. coli and for the first time among porcine, poultry and human E. coli. Sequencing of the afaE-8 amplicon of nine strains from the different host species showed a high degree of conservation (>95% at the DNA level; >92% at the amino-acid level). The afa-8 gene cluster was more frequent in E. coli from diseased calves (18%) than from piglets (12%), humans (6%) and poultry (5%). Bovine NTEC2 (26%) were more frequently positive than NTEC 1 (20%) and non-NTEC (11%). E. coli isolated from asymptomatic calves were rarely positive: one NTEC2 (3%) and no non-NTEC. The afa-8 gene cluster was located on the Vir plasmid in 11/23 NTEC2, but no plasmid localization was detected in NTEC1 or non-NTEC.     

A serological survey on classical swine fever (CSF), Aujeszky's disease (AD) and porcine reproductive and respiratory syndrome (PRRS) virus infections in French wild boars from 1991 to 1998

In early 1992, a CSF epizootic was clinically recognised in a wild boar population of approximately 1300 animals within an area of 250km(2) located in the east of France. In order to check the CSF situation in wild boars outside this area, a serological survey was carried out in the rest of France, for 8 consecutive years (1991-1998). This paper reports on the results obtained during this survey which included wild boars shot during the hunting period but also boars reared within fences. Around 1000-2700 sera a year were tested for the presence of antibodies to classical swine fever virus (CSFV) and also to Aujeszky's disease virus (ADV). Out of 12025 sera tested over the whole period, 80 wild boars were found positive for CSF antibodies. Sixty of them were collected on wild boars shot during the years 1992-1994 in the epizootic area located in east of France and 10 were collected in Corsica during the years 1994-1996. The last four positive samples were single reactors coming from areas or farms, which were thereafter confirmed to be serologically negative. These results together with the fact that no disease has been reported so far illustrate that the French wild boar population is probably not concerned by CSF infection (excepted in the east of France where the disease has now become enzootic). Two hundred and forty nine sera were initially detected as CSF positive but confirmed secondarily as positive for border disease (BD) antibodies. This finding shows that wild boars are also susceptible to infection by ruminant pestiviruses. Four hundred and twenty three wild boars have been found positive for ADV antibodies. In addition, from 1993 to 1995, 909 samples were tested for the presence of antibodies to porcine reproductive and respiratory syndrome virus (PRRSV). Thirty three of them were positive. The results on AD and PRRS antibody detection show that wild boars may constitute a reservoir for various infectious diseases of pigs.     

Development and validation of a radioimmunoassay for thyrotropin in cattle.

In mammals, thyrotropin, or thyroid-stimulating hormone (TSH), assay is used for the diagnosis of primary hypothyroidism. Hypothyroidism is the most common type of thyroid disorder in cattle. The aim of this study was to develop and validate, under physiologic and pathologic conditions, a radioimmunoassay (RIA) for bovine TSH (bTSH). Double RIA was performed with purified bTSH and specific bovine antiserum. Laboratory validation included research of minimal detection limit, accuracy, and reproducibility. The physiologic validation included a thyrotropin-releasing hormone (TRH) challenge performed on euthyroid cows and a follow-up of bTSH concentration over a 24-hour period. Furthermore, bTSH concentration was assayed in a large population of healthy dairy and beef cows to define reference interval. The pathologic validation was made by assaying bTSH and thyroid hormones on healthy and goitrous newborn calves. The minimum detection limit (MDL) for bTSH assay was 1.3 microU/ml. The recovery was 101% to 106%. The intra- and interassay coefficients of variation (CVs) ranged from 5% to 11% and 11% to 15%, respectively. The RIA covered the whole range of physiologic bTSH values, as shown by bTSH values induced by TRH-challenge. A pulsatile secretion of bTSH was observed, accompanied by a diurnal variation with lower night values than day values. Reference intervals of bTSH ranged from 1.3 to 13.0 microU/ml for beef and dairy breeds. Finally, bTSH easily discriminated goitrous newborn calves from healthy ones, leading to the definition of a cutoff value of 35 microU/ml. The bTSH assay positively reacted to physiologic and pathologic conditions. The accuracy and precision of the RIA were satisfying.     

Quantification of DNA of citrus huanglongbing pathogen in diseased leaves using competitive PCR

A quantification system for huanglongbing pathogen using a competitive polymerase chain reaction method and image-analyzing software were developed to obtain precise results. Significant differences in the quantity of pathogen were thus determined in leaves of two citrus cultivars commonly cultivated in southern Vietnam. Less pathogen-related DNA was detected from the tissue of citrus cultivars that are believed to be more tolerant than susceptible cultivars. The quantification system will be used in studies on pathogen proliferation and movement inside citrus tissue.     

灵芝发酵菌丝三萜类化合物含量的测定

建立了灵芝发酵菌丝三萜类化合物含量的检测方法。方法以齐墩果酸作为标准品．用香草醛一高氯酸发色体系进行比色．确定灵芝发酵菌丝三萜含量测定的实验条件．结果三萜类在20—140ug范围内有很好的线性关系．y=0．005x-0．019r=0．998。结论本法简便、准确、重复性好．可用于灵芝发酵菌丝三萜类含量的检测．以鉴定灵芝的品质及其产品的三萜含量。     

不同方式制备的猪胃消化液对培养猪多杀性巴氏杆菌（EO630株）的影响

在猪多杀性巴氏杆菌(EO630株)的菌液生产中,使用不同方式制备的猪胃消化液马丁汤培养基生产猪多杀性巴氏杆菌菌液,菌液菌数差异明显。结果表明用温室消化的猪胃消化液制备的马丁汤培养基有利于提高培养菌数。     

一例白鲸应激反应综合症的病例报道

本文就一例幼年雌性白鲸在运输后发生的应激反应综合症进行了诊断、治疗。临床表现为精神不振、拒食、体重下降、体色暗淡、巩膜及结膜充血、皮肤瘙痒;血液学检查表明轻度贫血和脱水、肌肉炎症及胃炎。后进行综合措施调整后,4d后恢复采食,2周后康复。同类鲸的疾病研究国内文献未见报道。