云南水牛资源及利用

云南水牛资源丰富,发展潜力大,本文简要论述了云南水牛的生态分布,体形外貌,遗传多样性及其生产性能,并指出云南水牛由役用型向役,肉,乳兼用型的利用方向发展。     

甘肃省坡耕地利用状况与退耕还林还草技术对策研究

对甘肃省坡耕地的利用状况及其退耕的可行性进行了较为全面的分析,按照因地制宜的原则,将退耕区域划分为陇中黄土丘陵沟壑区、陇东黄土台塬区、山高坡陡的陇南山区与河西防风固沙区四大区,并就各区退耕后的还林还草方式进行了具体的论证,提出了15°～25°和25°以上坡耕地退耕还林还草的具体技术对策。     

禁牧休牧监管立法的分析与探讨

禁牧休牧已成为保护和培育生态植被的一种主要方式,是遏制草原荒漠化的有效手段。相对于禁牧休牧的制度需求,其监管立法却存在诸多问题需要完善,本文从立法层级、监管体制、法律责任等方面分析了禁牧休牧监管立法中存在的问题,着重论述其完善途径,并提出了相应的立法建议。     

科尔沁沙地灌溉与施肥对退化草地生产力的影响

在科尔沁沙地典型退化草地上开展了裂区组合设计的灌溉与施肥二因素试验。结果表明,科尔沁沙地退化草地土壤储水量受降水量的影响强烈。由于受到干旱气候和灌溉量的影响,灌水仅对地表0~30 cm的土壤含水量变化有作用,对深层土壤的含水量没有作用。灌溉和施肥对沙地退化草地的植物生物量有着明显的促进作用。灌溉处理中,灌溉90 mm试验区的植被生物量为最高(128.3 g/m2),施肥处理中,每hm2施600 kg氮肥试验区的植被生物量为最高(147.3 g/m2)。灌溉90,60,30 mm和对照试验区的植被耗水量分别为379.00,349.90,313.20和293.50 mm。与其相应的水分利用率分别为0.28,0.38,0.34和0.35 kg/(mm.hm2)。综合分析认为科尔沁沙地退化草地的基本耗水量为294 mm。     

Influence of varying dietary electrolyte balance on broiler performance under tropical summer conditions

A 6‐week feeding trial was conducted to determine the effects of varying dietary electrolyte balance (DEB) on growth performance and physiological responses in broiler chicks reared during hot summer months (26.1–37.5 °C). The average minimum and maximum room temperatures recorded from 14 to 42 days of age were 26.1 and 37.5 °C, respectively, with relative humidity ranging from 51% to 55%. Five DEB treatments supplying 0, 50, 150, 250 and 350 (Na⁺+K⁺–Cl^?) mEq/kg of diet were prepared by adding NaHCO₃ and/or NH₄Cl to basal diet that contained 185 mEq/kg from 1 to 28 days and 172 mEq/kg from 29 to 42 days. These DEB diets were randomly offered to six experimental units of 20 chicks each. Improved 42‐day body weight gain (BWG), feed:gain (F:G) and reduced mortality was noted with DEB 50, 150 and 250 mEq/kg compared to DEB 0 and 350 mEq/kg. A quadratic effect of increasing DEB level was observed on BWG and F:G, whereas the effect was linear for feed intake, water intake and litter moisture. The DEB 50, 150 and 250 maintained better blood pH, pCO₂ and HCO₃ concentrations during acute heat stress periods than that of 0 and 350. The blood heterophil and lymphocyte percent as well as heterophil:lymphocyte were remained unaffected. The lowest DEB (0 mEq/kg) diet reduced the feed intake and promoted metabolic acidosis. At 350 mEq/kg DEB, water intake and metabolic alkalosis were promoted probably due to high levels of dietary NaHCO₃. The study concluded that overall better performance was recorded with DEB 50, 150 and 250 mEq/kg. These results indicated that single optimal DEB value could not be recommended to combat heat stress in broilers.     

IMP improves water‐holding capacity,physical and sensory properties of heat‐induced gels from porcine meat

Water‐holding capacity (WHC) of heat‐induced pork gels was examined. The heat‐induced gels were obtained from meat homogenates prepared by adding nine volumes of 0.3–0.5 mol/L NaCl solutions containing 9–36 mmol/L disodium inosine‐5′‐monophosphate (IMP) or 9 mmol/L tetrapotassium pyrophosphate (KPP) to minced pork. IMP at 36 mmol/L enhanced the WHC to the same level as attained by KPP. Physical and sensory properties of heat‐induced gels were also examined. The heat‐induced gels were prepared from porcine meat homogenates containing 0.3 mol/L NaCl and 9–36 mmol/L IMP or 9 mmol/L KPP. IMP at 36 mmol/L enhanced the values of hardness, cohesiveness, gumminess and springiness, measured with a Tensipresser, and several organoleptic scores to the same level as the score attained by KPP. Thus, it is concluded that IMP is expected to be a practical substitute for pyrophosphates to improve the quality of sausages.     

苗期紫花苜蓿品种抗旱性初步研究

运用多元统计分析方法,以来自、美国、澳大利亚、加拿大及中国的22个紫花苜蓿Medicago sativa品种（种群）为试验材料,对紫花苜蓿在苗期进行短期干旱胁迫,依据试验测定的15个形态指标和生理指标,应用主成分分析、聚类分析法,对22个紫花苜蓿品种试验材料的抗旱能力进行综合评价。通过运用主成分分析法将15项相关的抗旱性指标简化为5个独立且功能明确的主成分,并以5个主成分的得分系数运用聚类分析法把22份材料聚为三大类,从而将22份材料分为强抗旱性品种、中抗旱性品种、弱抗旱性品种,为下一步抗旱机制的研究提供参考。     

水分对柠条萌蘖株和未平茬株光合参数及调渗物质的影响

对柠条Caragana korshinskii平茬后的萌蘖株和未平茬的对照株在夏季旺盛生长期进行了水分处理,并研究了浇水前后萌蘖株和对照株光合参数及调渗物质的变化。浇水前,萌蘖株具有较高的水势 (LWP)、光合速率(A)、气孔导度(G)、蒸腾速率(E)、光系统II最大光化学量子效率(Fv/Fm)和光系统II实际量子产率(△F/Fm′);而对照株相应指标较低,但对照株光化学猝灭系数（NPQ）,脯氨酸(Pro)、 丙二醛(MDA)含量较高。浇水后,对照株LWP、A、G、E、Fv/Fm、△F/Fm′均有不同程度的上升,而NPQ值和Pro、MAD的含量下降。浇水对萌蘖株和对照株叶绿素(Chla+b)含量影响不显著,且浇水前后萌蘖株均高于对照株。结果表明：萌蘖株在生长季所受干旱胁迫较小,植物将更多的光能以光合作用的形式利用,植物生长迅速;而对照株所受干旱胁迫的影响较为严重,光合速率低,植物将更多的光能以热的形式消耗,导致植物生长缓慢。     

内蒙古阿拉善草地毒草灾害调查与控制对策

内蒙古阿拉善草地毒草灾害一直困扰着当地畜牧业的发展.采用以现场走访和查阅文献相结合的方式,对阿拉善草地毒草灾害的历史和现状、毒草灾害造成的损失、毒草种类和地理分布、主要毒草生物学特性等进行调查,提出草地毒草灾害控制对策.结果表明,阿拉善草地牲畜毒草中毒发病率高达60%,病死率为30%;形成优势种群的毒草有14种,其中造...     

The effects of potato pulp and feeding level of supplements on digestibility, in situ forage degradation and ruminal fermentation in beef steers

Six ruminally cannulated Wagyu (Japanese Black) steers (average initial bodyweight (BW) 387 ± 29 kg) were used in a split‐plot design experiment, comprising a 3 × 3 Latin square design (whole plot) and a randomized block design (subplot). The whole plot treatments were three different feeding levels of supplemental diet, fed at 0.2, 0.4 and 0.6% of BW, on a dry matter (DM) basis. Subplot treatments were two different supplemental diets: a potato pulp silage‐based diet (PPS) and a grain‐based diet (GRAIN). Chopped, medium‐quality cool‐season grass hay (predominately Timothy, Phleum pratense L) was fed daily at 0.7% BW (on a DM basis) as the basal diet. Each period consisted of 21 d, which included 11 d of adaptation to the diets and 10 d of the collection period. Chromium oxide was used as an indigestible marker. In situ forage degradation was measured using the nylon bag technique. The dry matter intake increased (linear; P < 0.01) as the feeding level increased and was not affected by the diet. Digestibility was not affected by any treatments. The GRAIN diet tended to decrease the rate of in situ forage degradation as the feeding level increased, but this trend was not found in the steers fed the PPS diet. Steers fed the GRAIN diet had a lower (P < 0.1) ruminal pH compared with steers fed the PPS diet. Ruminal pH was not significantly affected by feeding level; however, it was numerically higher for steers supplemented at 0.2% per BW than that for the steers supplemented above 0.4% per BW due probably to the higher starch intake. The total volatile fatty acids concentration numerically increased as the feeding level increased and was not affected by the diet. Increasing the feeding level decreased (linear, P < 0.01) the proportion of acetate. Neither diet nor the feeding level had any effects on the proportion of ruminal propionate. The results suggested that, for steers fed the PPS diet, there are not adverse effects on forage digestion in the rumen that occur as the feeding level is increased.