Sub-clinical parasitism in spring-born, beef suckler calves: epidemiology and impact on growth performance during the first grazing season     

Forbes AB  Cutler KL  Rice BJ 《Veterinary parasitology》2002,104(4):339-344

Sub-clinical parasitism in spring-born single suckled beef calves was investigated from the middle of their first grazing season until weaning or housing later the same year. The study was conducted on four beef suckler herds in southern England over a 3-year period and involved a total of 334 spring-born beef suckler calves and their dams. The animals were grazed extensively on pastures naturally infected with nematode larvae. At the start of each period of observation, faecal samples were taken from calves and cows and subjected to routine worm egg counts; calves were re-sampled at the end of the grazing season.In July in each year and at each location the calves were ranked by initial weight within sex, paired according to rank and randomly allocated to either an untreated control group or a group in which the calves were each treated with an ivermectin sustained-release (SR) bolus. The calves in both trial groups, and their dams, were grazed together until weaning or housing. The calves were weighed at the initial allocation and at the end of the study. The adult cows were not treated with any anthelmintic during the study.The faecal nematode egg counts (FECs) conducted in July showed that the suckler cows were excreting worm eggs at low concentrations: range 0-100 eggs per gram (epg), with one individual count of 500epg, 88% of the cows sampled had counts of <50epg. Similarly, the counts from the calf samples were fairly low in July: range 0-250epg, 73% of the calves sampled had counts of <50epg. By the end of the grazing season, the faecal samples from the untreated control calves showed higher values: range 0-650epg, with only 58% having an epg of <50.The average rate of daily liveweight gain in the untreated heifer calves was 0.79kg per day, the corresponding figure for the heifer calves treated with the ivermectin SR bolus in mid-summer was 0.88kg per day; the difference of 90g per day was significantly different (P=0.0118). The average rate of daily liveweight gain in the untreated bull calves was 0.91kg per day, the corresponding figure for the bull calves treated with the ivermectin SR bolus in mid-summer was 1.01kg per day; the difference was significantly different (P=0.0169).  相似文献   

Serological evidence of infectious bovine rhinotracheitis, bovine virus diarrhoea and parainfluenza-3 viruses in calves in El Salvador.     

D A Rice  E W Jenney 《Tropical animal health and production》1979,11(2):123-124

  相似文献   

Economic effects of increased vitamin E supplementation of broiler diets on commercial broiler production     

D. G. Kennedy  D. A. Rice  D. W. Bruce  E. A. Goodall  S. G. McIlroy 《British poultry science》1992,33(5):1015-1023

1. The economic effects of increased vitamin E supplementation in 168 commercial broiler flocks incorporating over 3 million birds was assessed using a computerised data retrieval system.

2. Approximately half of the flocks were fed on either a high (163 mg/kg) vitamin E or on a normal (44 mg/kg) vitamin E‐containing diet throughout production.

3. Approximately half of the flocks were the progeny of breeder flocks which had been fed on a high vitamin E‐containing diet throughout production.

4. The improvement in target income in the vitamin E‐supplemented broiler flocks was 8–44% (P < 0.01).

5. The residual improvement in target income in these flocks, after the cost of the additional vitamin E was taken into account, was 2.74% and failed to reach statistical significance.

6. The increased net income was achieved by a significantly improved food conversion ratio and average weight per bird (P < 0.05).

7. There was no overall effect of vitamin E supplementation of broiler breeders on subsequent broiler performance.  相似文献   

Ocular albinism and hypopigmentation defects in Slc24a5-/- mice     

Vogel P  Read RW  Vance RB  Platt KA  Troughton K  Rice DS 《Veterinary pathology》2008,45(2):264-279

As part of a high-throughput mutagenesis and phenotyping process designed to discover novel drug targets, we generated and characterized mice with a targeted mutation in Slc24a5, a gene encoding a putative cation exchanger. Upon macroscopic examination, Slc24a5-/- mice were viable, fertile, and indistinguishable by coat color from their heterozygous and wild-type litter mates. Ophthalmoscopic examination revealed diffuse retinal hypopigmentation, and a histologic examination of the eye confirmed the presence of moderate-to-marked hypopigmentation of the retinal pigmented epithelium (RPE), ciliary body, and iris pigment epithelium (IPE). Hypopigmentation was most severe in the anterior layer cells of the IPE, where melanosomes were smaller, paler, and more indistinct than those of the anterior stroma and posterior IPE. The pigment granules of the posterior IPE appeared to be nearly as dark as those in stromal melanocytes; however, both cell layers were thinner and paler than corresponding layers in wild-type mice. Ultrastructural analysis of the RPE, IPE, and ciliary body pigmented cells confirmed that mutation of Slc24a5 results in marked hypopigmentation of melanosomes in optic cup-derived pigmented neuroepithelium in the eyes. Milder reductions in melanosome size and pigmentation were noted in neural crest-derived melanocytes. The severe hypopigmentation of neuroepithelium-derived cells in the eyes resulted in a novel form of ocular albinism in Slc24a5-/- mice. Our findings suggest that SLC24A5 may be a candidate gene for some forms of ocular albinism and for the BEY1/EYCL2 locus previously associated with central brown eye color in humans.  相似文献   

Suicide by veterinary surgeons     

Rice D 《The Veterinary record》2008,162(11):355; author reply 355-355; author reply 356

  相似文献   

Production and isolation of aflatoxin M1 for toxicological studies     

D P Hsieh  L M Beltran  M Y Fukayama  D W Rice  J J Wong 《Journal of the Association of Official Analytical Chemists》1986,69(3):510-512

One hundred mg aflatoxin M1 was produced and purified for toxicological studies. Aspergillus flavus NRRL 3251 was cultured on rice to produce aflatoxins B1, B2, M1, and M2, B1 and B2 were separated from M1 and M2 by a normal phase low pressure liquid chromatography (LC) column. M1 was then separated from M2 by a reverse phase low pressure LC column. Recoveries of aflatoxins from the LC columns were about 90%. The purified M1 was confirmed by ultraviolet-visible spectrometry, mass spectrometry, nuclear magnetic resonance spectrometry, optical rotation, and its mutagenicity to Salmonella typhimurium TA98.  相似文献   

应用SSR和ISSR标记分析栽培香稻品种的遗传多样性   总被引：27，自引：0，他引：27  

王金花  罗文永  陈建伟  刘元风  吴秋花  李晓方 《分子植物育种》2005,3(1):37-42

本研究利用24对SSR引物和36个ISSR引物,分析33份来源于亚洲10个国家的香稻品种的遗传多样性。分别获得93条和181条多态性片段,每个SSR座位可检测3～8个等位基因,平均为4．23个;每个ISSR引物可检测3～8个多态性位点,平均为5．03个。根据SSR和ISSR标记计算的品种间遗传相似系数分别在0．294～0．884之间和0．595～0．867之间。聚类分析表明,利用两种标记所得的聚类结果基本上一致,与品种所处的3种气候类型变化基本相符。进一步证实SSR和ISSR标记是研究水稻种质资源分类有效的工具。  相似文献   

植物F-Box蛋白及其生物学功能研究(英文)     

李莉  夏凯  付岳峰  田妍 《（《农业科学与技术》）编辑部》2010,(7)

F-box蛋白是一类含有F-box结构域,在泛素介导的蛋白质水解过程中具有底物识别特性的蛋白质家族。这类蛋白质在细胞循环、信号传导、基因转录、雄性不育和细胞程序化死亡等多种生理过程中发挥重要作用。介绍了已知的植物F-box蛋白质的生物学功能并对F-box基因的系统进化进行了分析。  相似文献   

耕型红壤和红壤性水稻土铜的化学行为及施铜效应研究     

张杨珠  刘学军  李法云  袁正平  肖永兰  黄运湘  周清 《湖南农业大学学报(自然科学版)》1999,25(4):1

应用选择溶解性的化学提取和幼苗试验等方法,研究了湖南省几种耕型红壤及其发育而成的水稻土铜的化学形态及其与土壤有效铜的关系,以及红壤旱地改水田后施铜对水稻吸铜和幼苗生长的影响．结果表明,供试土壤中的铜主要以有机态（１５．２％ ）、无定形铁态（１１．７％ ）、晶形铁态（１７．２％ ）和残留态（５６．０％ ）４ 种形态存在,其中红壤性水稻土有机态铜（１８．７％ ）和无定形铁态铜（１４．６％ ）明显高于耕型红壤（分别为８．０％ 和５．８％ ）,而晶形铁态铜和残留态铜含量则是后者高于前者．红壤性水稻土有效铜含量显著高于耕型红壤．幼苗试验结果表明,耕型砂岩红壤施铜能明显促进水稻幼苗对铜的吸收,最佳施铜量为 ５～１０ ｍ ｇ／ｋｇ 土．  相似文献   

杂交稻强优恢复系南恢125的选育与应用     

江文清  谢冬容  刘端华  周仕全  应薛养  陈泳和 《勤云标准版测试》2007,(1)

在利用国内外优良恢复系作亲本杂交育成中间材料N175基础上,再聚合杂交,培育成功强优恢复系南恢125。该恢复系具有株叶形态优良、恢复力强、恢复谱广、配合力好、花粉量多、制种产量高、较抗稻瘟、米质优等特点。用南恢125配组的Ⅱ优125、泸优125、特优125等组合在各级区试中表现突出,其中Ⅱ优125于2006年通过福建省农作物品种审定委员会审定,显示出良好的生产应用前景。  相似文献