Management strategies for forage rape (Brassica napus L. cv Goliath): Impact on dry-matter yield,plant reserves,morphology and nutritive value

Limited information is available on the grazing management principles of forage rape (Brassica napus L.), particularly in relation to grazing height and intensity and the impact of these on dry-matter (DM) yield and nutritive value. A glasshouse study was undertaken to investigate the effect of three defoliation heights (plant height at harvest; DH: 40, 70 and 90 cm; L, M and H DH respectively) and three defoliation intensities (height at which plants were cut; DI: 5, 20 and 35 cm of residual height; H, M and L DI respectively) on forage rape (cv Goliath) yield and nutritive value at two harvests (harvest 1, H1 and harvest 2, H2), and the impact of nitrogen (N) and water soluble carbohydrate (WSC) reserves on regrowth. Increasing DH from L to H increased estimated total DM yield (H1 plus H2) from 0.5 to 4.6 t DM/ha but DI did not affect yield. Dry-matter yield was optimized at 90 cm DH, but greater nutritive value was achieved by harvesting at lower levels of DH. Despite high in vitro DM digestibility (IVDMD; 852–889 g/kg), harvesting at 90 cm DH could not meet the protein requirement of lactating dairy cows and harvesting at lower levels risks nitrate poisoning. Our results indicate the optimum DH may be between 70 and 90 cm DH, and 20 and 35 cm DI, which requires further studies.     

Perivascular wall tumour presenting as pastern mass in a Standardbred gelding

A 2-year-old Standardbred gelding was referred for a mass on the palmaromedial right front pastern which was accompanied by progressively worsening lameness. The mass was firm to palpation and covered by normal skin. Ultrasonographically, a smooth encapsulated mass was present, medial to the flexor tendons and palmar to the neurovascular bundle. Because of a poor prognosis for future athletic performance without surgical or chemotherapeutic intervention and economic constraints preventing further diagnostics and treatment, the horse was euthanised. Post-mortem magnetic resonance imaging, histopathology and immunohistochemistry revealed the mass to be a perivascular wall tumour, the first record of such a neoplasia in the horse.     

Prevalence of Cryptosporidium infection in goats in selected locations in three agroclimatic zones of Sri Lanka

The prevalence of Cryptosporidium oocysts in the faeces of 1020 goats in three age categories was examined during 1999 in selected locations of three agroclimatic zones of Sri Lanka. The oocysts were demonstrated using the Sheather's sucrose flotation method followed by staining with the modified Ziehl Neelsen technique. Cryptosporidium oocysts were detected in animals from all agroclimatic zones with the highest prevalence of infection in the dry zone (33.6%) compared with 24.7 and 21.7% in the intermediate zones and wet, respectively (P<0.001). Overall, Cryptosporidium oocyst counts were significantly higher in goats of <6 months and 7-12 months of age groups compared with goats of >12 months of age (P<0.001). Cryptosporidium oocysts were detected in 291/1020 (28.5%) animals, while 194/1020 animals (19%), 84/1020 animals (8.2%) and 13/1020 animals (1.3%) excreted low (1-1000 oocysts per gram of faeces), moderate (1000-5000 oocysts per gram of faeces) and high (>5000 oocysts per gram of faeces) counts, respectively. The mean Cryptosporidium count was 383 oocysts per gram of faeces. The majority of the infected goats were asymptomatic. These animals are likely to play an important role in the epidemiology of cryptosporidiosis in goat kids and humans.     

Surgical resection of a dysgerminoma in a mare

A mare was referred for further evaluation of a mass found in the left caudal abdomen during a routine postpartum reproductive palpation. The mare was clinically normal with no history of health problems. Ultrasonographic examination of the mass confirmed its presence, but the origin of the mass could not be accurately determined. Routine haematology and serum biochemistry results were within normal limits. The mare was initially treated conservatively with antibiotics, but the mass continued to increase in size, so it was surgically excised. The mass involved the left ovary. The mare showed transient abdominal pain after surgery, but developed no other complications and was in foal 7 months later. On histology, the mass was diagnosed as a dysgerminoma, a rare ovarian tumour of germ cell origin.     

Nutritive value of forage species grown in the warm temperate climate of Australia for dairy cows: Herbs and grain crops

The objective of this study was to quantify the nutritive characteristics of 6 grain crops and 4 herb forages over 4 seasons, when all species were grown at the same site, under the same climatic and edaphic conditions, and with soil moisture and nutrient availability being non-limiting to growth. The forages grown were maize (Zea mays), sorghum (Sorghum bicolor), millet (Pennisetum americana), wheat (Triticum aestivum), triticale (Triticum × secale), oats (Avena sativa), fodder radish (Raphanu sativa), rape (Brassica rapa), chicory (Cachorium intybus) and plantain (Plantago lanceolata). The in sacco degradation characteristics of organic matter (OM) and crude protein of herbages were measured in the rumen of cannulated sheep in order to calculate the availability of effective rumen degradable protein (ERDP), rumen by pass protein, metabolisable protein (MP) and the synchrony index (I_s), which describes the efficiency of utilization of degradable nitrogen (N) and OM for microbial protein synthesis (MPS) in the rumen.In this study, all grain crops except maize had a ERDP/fermentable metabolizable energy (FME) ratio varying from 14 for millet to 23 for wheat, well above the ratio of 11 required for optimum MPS in the rumen of dairy cows. In contrast, maize had the lowest ERDP/FME ratio of 3, indicating that ERDP would be limiting MPS in the rumen. The availability of MP varied from 58 g/kg DM in maize to 153 g/kg DM in wheat and all forage species except maize were be able to meet the MP requirement of high-producing dairy cows (30 L/milk/day) provided they were able to consume 11 to13 kg DM/cow/day of the forage.The availability of MP from herbs varied from 95 g/kg DM in fodder radish to 163 g/kg DM in plantain, which would be sufficient for high-producing cows, however, most dairy cows could not consume sufficient forage to achieve these high levels of production due to very high nitrate content in rape (mean of 11.1 g/kg DM) and fodder radish (mean of 8 g/kg DM).     

在松苗繁育中应用辛硫磷防治地下害虫

跃进农场根据多年的育苗经验 ,通过正确使用辛硫磷 ,在防治地下害虫方面取得了较为显著的效果。1　苗圃主要地下害虫种类及虫源金龟子 (螬 )、蝼蛄、小地老虎号称苗圃三大地下害虫 ,这些地下害虫的主要来源渠道为 :(1)老圃地的残枝败叶产生虫卵 ,久而久之泛滥成灾 ,加之防范措施不利 ,土壤老化滋生杂多的虫卵 ,使其产生虫源 ;(2 )未能及时翻耙 ,或翻耙深度不够 ,使地下虫卵长年繁殖 ,产生大量的幼虫 ;(3)圃地草荒严重 ,各类虫害频频发生 ,使潜藏在杂草内的虫卵和病菌繁衍生息 ;(4 )在改土施肥过程中使用的生土和未腐熟的肥料中带有虫卵 ,产…     

人体条件致病细菌-洋葱伯克氏菌在农业上的研究现状及风险分析

洋葱伯克氏细菌具有生物防治、促进植物生长和降解残留农药等功效，但它又是一种危险的人体条件致病菌。文章综述了以洋葱伯克氏菌为代表的人体条件致病菌特性，以及在农业上的研究应用现状、存在问题与风险，为该菌在农业上的深入研究及应用提供依据。     

麻黄愈伤组织诱导及其倍性鉴定

以草麻黄幼苗的幼茎和下胚轴为外植体,采用不同激素组合及浓度配比的MS培养基进行愈伤组织的诱导。结果表明:草麻黄幼茎愈伤组织诱导的最佳培养基为MS+1．1mg／L 2,4-D+0．2 mg／L KT。在MS+2 mg／L 6-BA +0．2 mg／L IAA的培养基上,下胚轴的诱导率高于幼茎。愈伤组织继代增殖的最佳培养基为MS+0．5mg／L 2,4-D +0．2 mg／L 6-BA,在其上继续生长,形成淡绿色、致密的愈伤组织,愈伤组织细胞主要为二倍体,也有少量的亚二倍体细胞和其它倍性细胞产生。