山毛豆草粉颗粒料对肉兔的饲用价值评定

为探讨山毛豆(Tephrosia candida)草粉对肉兔的饲用价值,将60只新西兰青年肉兔分为5组,分别添加0％(对照),10％,20％,30％和40％的山毛豆草粉制成全价颗粒饲料,饲喂90 d后测定各组饲料的营养成分及肉兔采食量、日增重、料重比和屠宰性能.结果表明:山毛豆营养生长期粗蛋白含量为17.77％,肉兔对山毛豆中粗蛋白的消化率为78.09％,山毛豆的可消化总养分为56.18％.与对照组相比,添加20％草粉日增重达到20.80 g·d-1(P＜0.01);料重比为4.45∶ 1(P＜0.05)；屠宰率为57.78％(P＜0.01)；单位kg增重平均最低饲料成本差异显著(P＜0.05).因此,添加20％山毛豆草粉制成全价颗粒饲料可显著提高肉兔的生产性能和养殖效益.     

Long-Term Effect of Fertilizer and Rice Straw on Mineral Composition and Potassium Adsorption in a Reddish Paddy Soil

Increasing K⁺ adsorption can be an effective alternative in building an available K pool in soils to optimize crop recovery and minimize losses into the environment. We hypothesized that long-term fertilization might change K⁺ adsorption because of changes in the chemical and mineralogical properties of a rice (Oryza sativa L.). The aims of this study were (i) to determine clay minerals in paddy soil clay size fractions using X-ray diffraction methods and a numerical diagram-decomposition method; (ii) to measure K⁺ adsorption isotherms before and after H₂O₂ oxidation of organic matter, and (iii) to investigate whether K⁺ adsorption is correlated with changes in soil chemical and mineral properties. The 30-yr long-term fertilization treatments caused little change in soil organic C (SOC) but a large variation in soil mineral composition. The whole-clay fraction (<5 μm) corresponded more to the fertilization treatment than the fine-clay fraction (<1 μm) in terms of percentage of illite peak area. The total percentage of vermiculite-chlorite peak area was significantly negatively correlated with the total percentage of illite peak area in the <5 μm soil particles (R=-0.946, P<0.0006). Different fertilization treatments gave significantly different results in K⁺ adsorption. The SOC oxidation test showed positive effects of SOC on K⁺ adsorption at lower K⁺ concentration (?120 mg L^?1) and negative effects at higher K⁺ concentration (240 mg L^?1). The K⁺ adsorption by soil clay minerals after SOC oxidization accounted for 60–158% of that by unoxidized soils, suggesting a more important role of soil minerals than SOC on K⁺ adsorption. The K⁺ adsorption potential was significantly correlated to the amount of poorly crystallized illite present (R=0.879, P=0.012). The availability of adsorbed K⁺ for plant growth needs further study.     

温度、食料条件对白背飞虱种群增长的影响

白背飞虱若虫和全世代发育速率与温度的关系呈逻辑斯谛关系,成虫产卵前期和卵的发育速率与温度的关系呈二次抛物线关系。在18—30℃下,卵孵化率比较稳定,水稻生育期对卵孵化亦无明显影响,孵化率平均为86.96％。若虫存活率、成虫产卵量和内禀增长力受温度和食料条件的影响十分明显,取食分蘖期和拔节期水稻的若虫存活率最高,成虫产卵量和内禀增长力最大。在水稻各生育期,若虫存活率、成虫产卵量和内禀增长力与温度的关系呈抛物线趋势。当温度达到35℃时,各生育期卵孵化率均下降到50％以下,且若虫陆续全部死亡。     

Phenotypes Including Immunocompetence in Scavenging Local Chicken Ecotypes in Tanzania

A study was conducted to determine the variations in physical characters and immunocompetence among scavenging local chicken ecotypes in Tanzania. Eighty-four adult scavenging local chickens from four eco-climatic regions of Tanzania were studied. Measurements of adult body weight, body length, shank length and egg weight and observations of plumage colour and pattern, earlobe colour, skin colour and the shape of the comb were conducted. The antibody response to sheep red blood cells, serum haemolytic complement and the cutaneous response to phytohaemagglutinin-P were assessed. Five ecotypes were identified and named Mbeya, Morogoro-medium, Ching'wekwe, Kuchi and Singamagazi. Singamagazi and Kuchi were significantly heavier, with longer shanks and heavier eggs than the other ecotypes. The average adult body weight for males ranged from 1621 g (Mbeya) to 2915 g (Singamagazi). Average female weights ranged from 1108 g (Morogoro-medium) to 2020 g (Singamagazi). Mean egg weights ranged from 37.65 g (Ching'wekwe) to 45.61 (Singamagazi). The Kuchi had mostly rose and walnut combs, while the other ecotypes were mostly single combed. In each ecotype there were chickens with a high or low antibody response to red blood cells, but there was a significant difference between the ecotypes.     

Evaluating Sugarcane Diets for Dairy Cows Using a Digestion Model

To eliminate unnecessary feeding trials, a mechanistic model of sugarcane digestion was used in the search for suitable supplements to improve milk production. Milk production simulated by the model was compared with data observed in four feeding trials published in the tropical literature where crossbred dairy cows were fed sugarcane/urea diets with different types of supplements. The predicted effects of the supplements on the ruminal microbial population, concentrations of ammonia and volatile fatty acids were also compared with the published results in one experiment. The model indicated the nutrient most limiting milk production for the different feeding situations. The addtion of Leucaena to the basal sugarcane/urea improved the availability of amino acids and long-chain fatty acids, with energy becoming the limiting factor. Supplementation with rice bran increased the availability of energy and long-chain fatty acids, but amino acids then became the limiting factor. Supplementation with both Leucaena and rice bran further improved the milk yield, but availability of energy now limited milk production. Supplementation with Leucaena increased milk production more than supplementation with king grass. The main reason for this increase was increased amino acid absorption due to increased microbial outflow. In all feeding situations, the average difference between the predicted milk production and that observed experimentally was 0.57 kg/d (ranging from 0.08 to 1 kg/d).     

Preliminary Epidemiological and Clinical Observations on Shimao Zheng (Fleece-Eating) in Goats and Sheep

Veterinary Research Communications -     

集雨栽培冬小麦田土壤水分和矿质氮

在半湿润易旱地区的关中红油土上,研究了垄上覆膜集雨栽培措施对冬小麦(Triticumaestivum)田土壤水分和矿质氮的影响。结果表明覆膜有一定的蓄水保墒效果,冬小麦返青期,0～40cm土壤贮水量覆膜处理比不覆膜处理平均多7.7mm;覆膜能使冬小麦在生长后期更有效地利用土壤深层贮水,在小麦成熟期,100～200cm土壤贮水量覆膜处理比未覆膜处理少23.8mm。覆膜有利于作物对氮肥的吸收利用,氮肥用量相同的处理,覆膜条件下的硝态氮浓度和矿质氮累积量低于不覆膜处理;施氮也可以明显增加土壤剖面中的硝态氮含量和矿质氮累积量。     

Concentrations of macro- and micro-elements in the milk of pasture-fed thoroughbred mares

OBJECTIVE: To determine the changes in Ca, P, Mg, Na, K, S, Cu, Fe and Zn concentrations of milk during the lactation in pasture-fed Thoroughbred mares and then calculate the dietary mineral requirements of the sucking foal and the lactating mare. PROCEDURE: Milk was sampled on days 1, 3, 7, 14, 21, 28 and at various times between 55 to 65, 85 to 95 and 135 to 150 days after parturition from 21 pasture-fed mares. The concentrations of macro- and micro-elements in the milk were determined by inductively coupled plasma emission spectrometry. RESULTS: Concentrations (mg/L) of these elements were highest in colostrum (Mg 302, Na 561, K 955, S 1035, Cu 0.76, Fe 0.79 and Zn 5.5) except for Ca (1245) and P (895), which where highest on day 7. The mean milk mineral element concentrations (mg/L) over days 55 to 150 were Ca 843, P 543, Mg 47, Na 120, K 590, S 219, Cu 0.19, Fe 0.34 and Zn 2.1. The mean plasma element concentrations (mg/L) over the same period were Ca 120, P 77.1, Mg 17.0, Na 3110, K 168, S 983, Cu 1.1, Fe 1.5 and Zn 0.49. Concentration gradients between plasma and milk were observed and, in the case of Ca, P, Mg, K and Zn, their concentrations in milk were greater than those in plasma, while a reverse situation was observed for Na, S, Cu and Fe. CONCLUSION: With the exception of Ca and P, the highest concentrations of mineral elements were observed in the colostrum. The nursing foal should have access to good pasture or creep feed, because the intakes of Ca, P and Cu from milk may be less than optimum to meet the daily mineral element requirements.