放牧苜蓿品种选育研究进展

苜蓿放牧草地以其成本相对低(与干草型苜蓿草地相比)、营养价值高、放牧家畜生产性能优异得到了家畜生产者的青睐。长期以来苜蓿的利用一直是以生产干草为主。多数干草型品种的耐牧性并不好，因此选育耐牧性强的苜蓿品种是育种家的重要目标。国外1990年后推出的耐牧性品种不仅耐牧性强。且抗病虫害能力强、产草量高、适口性好。为此。从放牧型苜蓿品种的特点、选育指标、选育过程及放牧苜蓿品种的评价体系等方面。综述了放牧型苜蓿育种的研究进展，为今后我国放牧型苜蓿品种的选育提供指导。     

苜蓿放牧地生产性能与管理

苜蓿(Medicago sariva)放牧草地以其成本相对低、营养价值高、家畜生产性能优异而得到生产者的青睐.但用于干草的苜蓿不耐践踏,不适合放牧,而且家畜鼓胀病也限制其利用,因而使之成为苜蓿科研的新方向.有关放牧型苜蓿品种的选育以及家畜鼓胀病的管理研究,笔者将分别在其他文章中阐述.本文主要就苜蓿放牧地的管理(放牧方式、时间和强度)、合理利用及其对不同家畜生产性能的影响,以及目前育成的放牧型苜蓿品种进行综述,以期为苜蓿放牧的管理和利用提供参考.     

适宜放牧的根蘖型苜蓿新品种放牧利用研究

筛选新育成的根蘖型苜蓿品种综合种4号、5号、6号共三个品系,建立人工放牧草地,第二年进行2次放牧。按放牧前后植被特征(盖度、密度、株高、根蘖发生率等)和产草量来比较,综合种6号、5号、4号均优于加拿大兰吉兰德根蘖型苜蓿和公农1号紫花苜蓿,并具有耐牧性强的特点。     

适宜放牧的根蘖型苜蓿新品种放牧利用研究

筛选新育成的根蘖型苜蓿品种综合种 4号、5号、6号共三个品系 ,建立人工放牧草地 ,第二年进行2次放牧。按放牧前后植被特征 (盖度、密度、株高、根蘖发生率等 )和产草量来比较 ,综合种 6号、5号、4号均优于加拿大兰吉兰德根蘖型苜蓿和公农 1号紫花苜蓿 ,并具有耐牧性强的特点。     

黄花苜蓿个体水平耐牧性的形态学成因机制研究

为揭示黄花苜蓿(Medicago falcata L.)耐牧性的形态学成因机制,探索其耐牧型品种选育的新途径。以从耐牧性鉴定中获得的耐牧性强和弱的2组黄花苜蓿个体植株为材料,对其放牧前后的相关形态指标的观测数据进行分析。结果表明:各形态指标与耐牧性强弱的显著性相关程度依次为根颈宽度>根颈入土深度> 茎数> 株高,对黄花苜蓿耐牧性的促进作用大小依次为根颈入土深度> 根颈宽度> 茎数> 株高> 株丛茎>植株投影盖度。根颈入土深度可单独增强黄花苜蓿的耐牧性,其他性状则通过相互协同作用促进其耐牧性。具有根颈粗大且入土深、单株茎数多且株丛大的黄花苜蓿植株耐牧性强,可作为耐牧育种材料早期选育的形态学指标。     

草种的选择

种草的草种和品种应按利用形式(刈剂、放牧或刈割与放牧结合)来选定。刈割利用时,牧草的产量是最重要的。为此,要选高大直立型的和营养价值随时间变化小、收获适期长的草种,放牧利用时,应选定再生能力强、耐家畜践踏、适口性强的草种。一般地说,寒地型禾本科疏从性草(鸡脚草、(?)状羊茅等)适于刈割放牧,匐匍型草种(草地早熟禾,小糠草等)适于放牧;豆科的红三叶、苜蓿适于刈割;白三叶适于刈割、放牧;高燕麦草适于调制干草。暖地型的牧草适于刈割的有:象草、无芒虎尾草等;放牧用的有巴哈雀稗、毛花雀稗。     

适宜放牧的“图牧3号”和“图牧4号”根蘖型苜蓿新品种选育及放牧利用研究

针对我国北方广大半干旱草原的生境条件，培育适宜放牧的根蘖型苜蓿新品种是当务之急。我所于1984年开始采用综合育种手段，育成“图牧3号”和“图牧4号”根蘖型苜蓿新品种，经7年时间生产应用，鲜草产量明显高于加拿大“Rangelander”苜蓿和内蒙地方品种准噶尔苜蓿。1995年起建立单播和混播人工草地，根蘖率和产草量完全超过育种指标，具有持久、耐牧和抗逆性强等特点。2000年先后在美国和加拿大半干旱草原带试种，放牧利用效果显著。目前在国内已建立2个种子繁育基地，为提供天然草地补播和建立人工放牧草地所需要的种子。     

不同放牧强度对根蘖型苜蓿＋羊草混播草地和细毛羊生产性能研究（初报）

不同放牧强度对草地生存环境和家畜生产性能的影响是密切相关的。采用3种不同放牧强度(每只羊1000、1333．4、1666．8m^2)对根蘖型苜蓿 羊草混播人工草地，进行分区轮牧试验。研究表明在中、低度放牧强度下，牧草的根蘖(分蘖)率、产草量和细毛羊增重都有明显的增长，对根蘖型苜蓿的耐牧、高产和适应性强等特点有所了解。     

苜蓿与放牧家畜臌胀病研究概况

饲喂新鲜苜蓿Medicago sativa时,家畜患臌胀病的风险很大,因此苜蓿传统上主要用作调制干草,放牧利用较少.就家畜臌胀病的概念、引发的原因及放牧管理中的相应预防方法和紫花苜蓿引起的臌胀病做一简要综述,旨在阐明已知的臌胀病可能起因及防治方法,为容易引起家畜臌胀病的苜蓿及其他相关豆科牧草的合理放牧利用提供指导.     

家畜的选择性采食对草地植物的反应

在放牧生态系统中,家畜和草地植物共同组成了草地放牧生态系统中的采食者与被采食者, 两者的关系是极其复杂的,家畜的选择性采食促进了植物抗牧性的发展,而植物抗牧性的发展又进一步强化了家畜的选择性采食习性,家畜和植物成为一个事物不可缺少的两个方面.     

白术、微米白术和白术多糖对断奶仔猪生长性能和肠道形态及微生态区系的影响

试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。     

Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia

Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.     

Feline intracranial neoplasia: retrospective review of 160 cases (1985-2001)

The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.     

Y‐chromosomal variation of local goat breeds of Turkey close to the domestication centre

Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.     

A brief history of the prevention of infectious diseases by immunisations

Infectious diseases have always been a terrible scourge for humans. The appearance of these plagues, as they were called without distinction, was generally connected to various conditions: asters, climatic changes or religious reasons. The concept of contagious, and then infectious, diseases came slowly. Variolation, i.e. transmission of ‘virulent’ matter to induce a natural disease and the immunity against it, was brought from Constantinople to England by Lady Montague, in 1721. This ‘variolation’ technique was also often performed in veterinary medicine against diseases like sheep-pox or pleuropneumonia. As ‘vaccination’ is the term generally accepted for ‘immunisation’, variolation can be the word designating such a technique. The second period of the history of immunisation began, in 1880, with the studies of Pasteur and his collaborators. A great number of bacterial vaccines were developed: dead, live but attenuated or only parts of pathogens. The viruses were produced in animals, then in eggs and at last, in tissue cultures. Second generation vaccines appeared with genetic engineering: recombinant vaccines, vector vaccines, nucleic acids vaccines, and markers vaccines, among others. These novel technologies can permit the development of new ones and improve the quality of the vaccines already existing.     

Micronutrient Content of Certain Tropical Conventional and Unconventional Feed Resources of Southern India

The ash, silica and certain important micronutrients were estimated in conventional and unconventional feed and fodder resources available in Southern India. Commonly used dry roughages, such as paddy straw, ragi straw, maize kadbi/stalk, jowar kadbi/stalk, bajra stalk and wheat straw, were high in ash (9.9% +/- 0.77%) and silica (6.4% +/- 0.65%) and low in most of the other micronutrients, except iron, with paddy straw containing most silica (>9%). Cultivated non-leguminous (maize, jowar) and improved green crops (hybrid napier, guinea, green panic, NB-21, CO-1) were also high in ash (10.5% +/- 0.60% and 12.5% +/- 0.51%) but were moderate sources of P, Mg and Cu and good sources of Zn (98 +/- 13.8 ppm and 55 +/- 6.7 ppm). Leguminous green fodders (stylosanthus, lucerne, cow pea, soyabean) were excellent sources of Ca (1.9% +/- 0.16%), Mg (0.40% +/- 0.05%), Cu (30 +/- 5.2 ppm), Zn (121 +/- 14.7 ppm) and Fe (1234 +/- 166 ppm) and moderate sources of P. Mixed local grasses and weeds were high in silica (6.9% +/- 1.00%) but were good sources of Cu, Zn and Fe. Cereal grains (maize, wheat, rice, ragi) were low in ash (2.9% +/- 0.33%) and were relatively poor sources of Ca (0.22% +/- 0.03%), Mg (0.19% +/- 0.03%) and Cu (13 +/- 3.1 ppm). Pulses were low to medium sources of most minerals and good sources of Fe (1230 +/- 293 ppm). Oil seed cake/extractions (groundnut cake, cotton seed cake, soyabean meal, sunflower cake, safflower cake) and cereal by-products (rice polish, rice bran, wheat bran) were excellent sources of P (1.1% +/- 0.47% and 2.3% +/- 0.19%) and good sources of Zn (65 +/- 3.9 ppm and 66 +/- 10.7 ppm) and Fe (938 +/- 130 ppm and 662 +/- 126 ppm). Among the unconventional feeds screened, orange peel, sunflower heads, meat meal, rubber seed cake, spirulina algae and sea weeds contained plentiful Ca, Zn and Fe: tree leaves/top feeds (mulberry, erythrina, glyricidia, banana, subabul, groundnut haulms) were excellent sources of Ca (1.5% +/- 0.13%), Zn (120 +/- 22.9 ppm) and Fe (1033 +/- 133 ppm) but relatively poor sources of P. Soyabean husk, cocoa seed husk, rubber seed cake and meat meal were moderate to good sources of P (1.0% and 0.33%). The high Zn and Fe values of most feeds/fodders were probably due to soil contamination. This account of the micronutrient content of feed/fodder resources should help in strategic supplementation intended to alleviate local deficiencies.     

Bovine Mastitis in Selected Areas of Southern Ethiopia

A study on bovine mastitis, designed to determine the causal agents, prevalence of infection and impact of risk factors in three cattle breeds, was conducted in selected areas of southern Ethiopia. A total of 307 lactating and non-lactating cows, of which 162 were indigenous Zebu, 85 Jersey and 60 Holstein-Friesian, were examined by clinical examination and the California mastitis (CMT) test. Of these, 40.4% were positive by CMT and bacteriology for clinical or subclinical mastitis, with prevalence rates of 37.1% and 62.9%, respectively. Out of 1133 quarters examined, 212 (18.7%) were found to be infected, 83 (39.2%) clinically and 129 (60.8%) subclinically. The prevalence of mastitis was significantly higher in Holstein-Friesian than in indigenous Zebu, in non-lactating cows than in lactating cows, in the early lactation stage than in the mid-lactation stage, in cows with lesions and/or tick infestation on skin of udder and/or teats than in cows without this factor, and in the wet season than in the dry season. Mastitis increased with parity number (R = 0.9). Of 248 CMT and clinically positive udder quarter samples analysed microbiologically, 212 were culturally positive for known mastitis pathogens and 36 were negative. Of the 199 positive samples, Staphylococcus accounted for 39.2%, Streptococcus for 23.6%, coliforms for 14.1%, Micrococcus and Bacillus species for 8.0% each and Actinomyces or Arcanobacterium (Corynebacterium) for 7.0%. It was concluded that there was a high prevalence of clinical and subclinical mastitis, mainly caused by Staphylococcus aureus, Streptococcus agalactiae and Escherichia coli, in this study area.     

不同日粮氮水平对山羊氮代谢和微生物蛋白质合成的影响

本试验旨在探讨不同日粮氮水平对内蒙古白绒山羊氮代谢和微生物蛋白质合成(MCP)的影响,以达到提高氮利用率,减少环境污染和饲料资源的浪费。试验选用9只体况良好、体重为(43.83±2.95)kg,装有瘤胃瘘管的内蒙古白绒山羊,按体重随机分为3组,每组3只。日粮分为低氮7.5%、中氮10.5%、高氮13.5%3个氮水平。试验使用常规试验方法分析测定粪尿血液等生化指标,通过全收尿法和尿嘌呤衍生物法估测MCP。结果表明:随着氮水平增加,氨氮(NH3-N)浓度、氮摄入量、尿氮排出、尿中尿素氮(UUN)和MCP显著增加(P0.05),干物质采食量(DMI)显著降低(P0.01);沉积氮占总摄入氮的比例在中氮组最高,MCP在高氮组最高。综上所述,适当降低日粮氮水平可减少粪尿氮排放,提高反刍动物氮利用率。     

Microsporidial keratopathy in two dogs

A microsporidial keratopathy is described in two dogs. Both dogs presented with a unilateral stromal keratopathy characterized by multifocal coalescing opacities, and the diagnosis was made on histopathologic examination of keratectomy specimens. Transmission electron microscopy (TEM) on formalin‐fixed, paraffin‐embedded corneal tissue was performed in one dog, and the morphologic features were consistent with Nosema species infection. Both dogs were initially diagnosed and treated by superficial keratectomy. One dog received additional antifungal medication and underwent a penetrating keratoplasty following local recurrence two years later. No other systemic lesions attributable to the microsporidial infection were identified clinically. The clinical and diagnostic pathology findings, treatment, and follow‐up are discussed.