Measurement of Sterigmatocystin Concentrations in Urine for Monitoring the Contamination of Cattle Feed

This study aimed (1) at determining the levels of the fungal toxin sterigmatocystin (STC) in the feed and urine of cattle and (2) at evaluating the effects of supplementing the feed with a mycotoxin adsorbent (MA) on STC concentrations in urine. Two herds of female Japanese Black cattle were used in this study. The cattle in each herd were fed a standard ration containing rice straw from different sources and a standard concentrate; two groups of cattle from each herd (n = six per group) received the commercial MA, mixed with the concentrate or given as top-dressing, whereas a third group received no supplement and served as control. Urine and feed samples were collected at various time points throughout the experiment. STC concentrations were measured using liquid chromatography-tandem mass spectrometry (LC-TMS). STC concentrations in straw were higher in Herd 1 (range 0.15–0.24 mg/kg DM) than in Herd 2 (range <0.01–0.06 mg/kg DM). In Herd 1, STC concentrations in urine significantly declined 2 weeks after replacing the contaminated feed, whereas MA supplementation had no effect. In conclusion, mycotoxins in urine samples are useful biological markers for monitoring the systemic exposure of cattle to multiple mycotoxins, as well as evaluating the effectiveness of interventions.     

Vitamin and mineral content of value cuts from beef steers fed distiller's grains

Selected vitamin (vitamin E, thiamin, riboflavin, niacin, vitamin B₆, and vitamin B₁₂) and mineral (calcium, phosphorus, magnesium, potassium, sulfur, iron, copper, zinc, manganese, and sodium) concentrations were determined for the value cuts—flat iron steaks (musculus infraspinatus) and petite tenders (musculus teres major) from cross-bred steers fed finishing rations containing 0% or 40% DM wet distiller's grains plus solubles (WDGS) with and without added daily supplemental vitamin E. The feeding treatment groups were: 0% WDGS with basal vitamin E (n = 6), 0% WDGS with supplemental vitamin E (500 IU/steer top-dressed daily) (n = 7), 40% WDGS with basal vitamin E (n = 8), and 40% WDGS with supplemental vitamin E (n = 8). Few differences in micronutrient concentrations were observed in either cut by treatment groups. Feeding steers diets containing 40% WDGS decreased vitamin B₁₂ and increased sodium concentrations in flat iron steaks and increased thiamin and decreased manganese concentrations in petite tenders. Significant differences in α-tocopherol concentrations in both cuts were observed by vitamin E grouping. Several significant differences were observed by cut. Uncooked flat iron steaks and petite tenders from these steers are rich sources of vitamin B₁₂, zinc, and sometimes phosphorus, good sources of riboflavin, niacin, vitamin B₆, and iron, and low in sodium.     

Serological Detection of Antibodies to Peste des Petits Ruminants Virus in Large Ruminants

Peste des petits ruminants (PPR) is an economically important disease of small ruminants with a rapidly expanding geographical distribution. Peste des petits ruminants virus may manifest in a variety of ways with disease ranging from acute to subclinical. We investigated the exposure of large ruminants to PPRV in areas where the virus is endemic in the small ruminant population by assessing the serological status of groups of animals. This study focused on the Punjab province of Pakistan as an area where the virus is endemic and where mixed farming practices occur enabling close interactions between small and large ruminant populations. An overall PPR seropositivity was detected in 10.0% of cattle and 14.16% of buffaloes. Following an assessment of serological profiles in large ruminants within different age groups, a maximum seroprevalence was observed in cattle (17.5%) and buffaloes (22.5%) over 2 years of age indicating the potential utility of sampling large ruminant populations for PPR serosurveillance. The large ruminants sampled between one and two years of age had similar levels of seropositivity within populations with 11.2% and 16.2% of animals being seropositive, respectively. Current PPR vaccination strategies do not enable the differentiation between infected and vaccinated small ruminants, and as such, the serological surveillance of sheep and goats is of little value. When considering eradication programmes for PPRV, this factor is of great significance. However, where large and small ruminants are farmed together, serological surveillance of large ruminants may provide a snapshot of virus infection within populations where mild disease is present or where small ruminants are regularly vaccinated.     

An Outbreak of Bovine Besnoitiosis in Beef Cattle Born in Central Italy

An outbreak of bovine besnoitiosis in three female, 15–18 months old beef cattle in central Italy is here described. All the animals were born in central Italy without any recent contact with imported animals. The animals were in poor body conditions and showed symptoms and clinical signs consistent with chronic besnoitiosis. The diagnosis was confirmed by histopathologic examinations of skin biopsies and whole body at necropsy, showing typical 50–100 μ cysts engulfing superficial dermis in skin and lamina propria in mucosae; lesions were confined to skin and respiratory mucosae, and cysts were not seen in any other tissue. Bovine besnoitiosis is rapidly spreading among European countries and in our case the affected animals were born in the farm and not recent admission was referred, so it is likely to consider this as an autoctone outbreak of the disease in Italy. This case, taken together with other recently reported ones, suggest to consider Italy among potentially endemic areas for bovine besnoitiosis.     

广角、水牛角和黄牛角中无机元素的比较研究

对广角、水牛角和黄牛角中的钙、镁、铁、锌、铜、锰、钴和铅进行了测试，结果显示３种角既有一定的相似性，又有差异性。     

前胡丙素对牛主动脉平滑肌细胞增殖的抑制作用

目的:探讨前胡丙素(pra-C)对牛主动脉平滑肌细胞(SMC)增殖的影响 方法:细胞DNA的合成量由~3H-胸腺嘧啶核苷[~3H]TdR)掺入试验测定,应用流式细胞术测定细胞周期,用乳酸脱氢酶活性测定观察药物的毒性.结果:无论有无血管紧张素Ⅱ(AngⅡ),在0.01μmol/L到10μmol/L浓度范围内,pra-C均可呈浓度依赖性地抑制SMC的增殖,抑制作用主要与阻止细胞进入有丝分裂期有关,而与细胞毒性无关.结论:pra-C能够完全阻断Aug Ⅱ诱导SMC的增殖效应,部分阻止小牛血清诱导的细胞分裂,这对于血管增生性疾病的防治有重要意义.     

Relationship between follicle size at insemination and pregnancy success

Administration of gonadotropin-releasing hormone (GnRH) induces a surge of luteinizing hormone and ovulation in a variety of species, including human beings. Our objectives were to determine the effect of follicle size at the time of ovulation on corpus luteum function and establishment and maintenance of pregnancy in cows in which ovulation was either spontaneous or induced with GnRH. GnRH-induced ovulation of follicles < or approximately = 11 mm in diameter resulted in decreased pregnancy rates and increased late embryonic mortality. This decrease in fertility was associated with lower circulating concentrations of estradiol on the day of insemination, a decreased rate of increase in progesterone after insemination, and, ultimately, decreased circulating concentrations of progesterone. In contrast, ovulatory follicle size had no apparent effect on fertility when ovulation occurred spontaneously. Follicles undergoing spontaneous ovulation do so at a wide range of sizes when they are physiologically mature. Therefore, administration of GnRH to induce ovulation likely initiates a preovulatory gonadotropin surge before some dominant follicles attain physiological maturity. GnRH-induced ovulation of follicles that are physiologically immature has a negative impact on pregnancy rates and late embryonic/fetal survival. These observations in cattle may have implications for assisted reproductive procedures in human beings.     

Molecular cloning and functional expression of a serotonin receptor from the Southern cattle tick, Boophilus microplus (Acari: Ixodidae)

A full-length cDNA encoding a 5-hydroxytryptamine (5-HT) receptor from the Southern cattle tick, Boophilus microplus, was isolated using a strategy based on sequence homology among G protein-coupled receptors. The deduced amino acid sequence revealed highest identity with Drosophila melanogaster 5HT-dro2A (Z11489, 50.8%) and 5HT-dro2B (Z11490, 49.5%) receptors. The receptor was transiently expressed in mammalian HEK293 cells, and Western blot analysis showed the expected 43.3 kDa band. In these cells, application of 5-HT (10 microm) inhibited forskolin-induced cAMP synthesis by 26%. The results indicate that the tick receptor is an invertebrate 5-HT1-like receptor that couples to Galphai protein.     

对苯二酚与牛血清白蛋白相互作用研究

目的探讨对苯二酚与血清白蛋白的相互作用。方法在0．05mol／LNa2HPO4-0．05mol／LNaH2PO4—0．10mol／LNaCl缓冲溶液中（pH=7．30），观察对苯二酚及牛血清白蛋白与对苯二酚结合后在L-半胱氨酸修饰金电极上的电化学行为。结果牛血清白蛋白与对苯二酚结合后可使对苯二酚的氧化峰峰电位正移，还原峰电位负移，且使苯二醌还原峰电流减小，根据对苯二酚、对苯二醌和血清白蛋白结合的饱和度，计算苯二酚、对苯二醌和血清白蛋白结合比分别为48：1和16：1。结论牛血清白蛋白与对苯二酚结合以较强的氢键结合。对苯二醌与血清白蛋白结合力较大。     

牛若干脏器新鲜组织RNA对体外瘤细胞的抑制作用

用十二烷基硫酸钠热酚法,从牛各脏器组织中提取并测定了RNA的含量。结果表明,牛胰腺中RNA含量为其他脏器组织的3～4倍。在体外做对瘤细胞杀伤作用的实验结果表明,牛胰腺和心脏RNA对瘤细胞的杀伤作用最大,其他组织的RNA也有一定程度的杀伤作用。