尕海地区弃耕地土壤可溶性盐分测定     

陆家宝 《青海畜牧兽医杂志》1995,25(3):21-22

１９９０～１９９３年在柴达盆地尕海地区弃耕地进行土壤可溶性盐分测定，测定结果，该地区土壤盐分组成为氯化物－硫酸盐和硫酸盐－氯化物，大部分地区耕层盐分含量小于１０ｇ．ｋｇ＾－１，少部分盐荒地表层含盐量高达７０ｇ．ｋｇ＾－１，牧草生长季节中，土壤盐分含量最低期在６月份。  相似文献   

胶合板厂生产规划模型与运用     

居志建  卢晓宁 《木材工业》1995,9(2):5-9

本文根据胶合板厂实际情况，建立了杨木胶合板厂生产规划模型。该模型考虑各主要设备工段、产品组合、产品混合、产品价格、流动资金、原材料供应以及市场约束等问题。本模型能够满足市场竞争，获取最佳利润，同时还能解决胶合板厂“三板”（表、背、芯单板）不平衡问题。  相似文献   

Correlated responses from selection for income minus food cost in pullets on traits in older hens     

C. Hagger  D. Steiger‐Stafl 《British poultry science》1991,32(5):971-979

1. After 5 generations of selection on income minus food cost between 21 and 40 weeks of age (SECR), a correlated genetic improvement of 14.5% and 16.3% of the base population mean could be observed for income minus food cost between 41 and 60 weeks (IF60) in two lines of laying hens. The total responses up to 60 weeks amounted to 17.2% and 17.3% of the base population mean. A heritability of 0.30 for IF60 and a genetic correlation of 0.61 between SECR and IF60 were estimated.

2. The correlated relative genetic responses for 5 traits of the period between 41 and 60 weeks of age for the two lines were: 4.3% and 5.2% in egg number, 5.8% and 7.4% in egg weight, 8.4% and 10.8% in egg mass, ‐2.7% and ‐0.6% in body weight at 60 weeks, and ‐5.2% and ‐6.3% in food efficiency.

3. The estimated heritabilities of these 5 traits from the whole data set were 0.36, 0.75, 0.34, 0.71 and 0.17. The estimated genetic correlations between SECR and the same 5 traits were 0.30, 0.46, 0.61, ‐0.22 and ‐0.49.

4. A high genetic correlation of income minus food cost with egg weight and a low one with egg number were found in pullets, but the relationships were reversed in older hens.  相似文献   

Effects of an induced pause in egg production and supplementation of the diet with iron on egg shell colour,quality and performance of brown egg layers     

H. Karunajeewa  S. Abu‐Serewa  Pamela A. Harris 《British poultry science》1989,30(2):257-264

1. A pause in egg production was induced in brown‐egg laying hens, aged 68 weeks, by feeding them whole oats for 7 d. Subsequently, these hens, together with control groups, were given laying diets with either 400 or 600 mg/kg iron. The 200 mg/kg of supplemental iron was added in the form of either ferrous sulphate or iron proteinate (chelated iron).

2. The feeding of whole oats halted egg production in 5.7 ±0.22 d and the duration of the pause was 8.3 ±0.78 d.

3. The induction of a pause improved the subsequent rate of egg production, egg output, efficiency of food utilisation, albumen quality, egg specific gravity and shell colour. It also increased food intake and body weight gain but neither egg weight nor the rate of mortality were affected.

4. Neither supplementation of the diet with iron nor its source had any significant effect on laying performance, egg quality or shell colour.  相似文献   

Studies on acid oils and fatty acids for chickens. III. Effect of chemical composition on metabolisable energy of by‐products of vegetable oil refining     

B. Vilà  E. Esteve‐Garcia 《British poultry science》1996,37(1):131-144

1. Fourteen by‐products of oil refining, selected for their variability in free fatty acid and unsaponifiable contents, were analysed chemically with the objective of relating the determined ME values of the products to chemical composition by means of multiple linear regression analysis. Refined sunflower oil was included as a reference fat.

2. Twenty‐one 2‐week‐old chicks were used to determine fat digestibilities and AMEn values of diets, using the total collection method. Fats were included in a wheat‐soyabean meal diet at 100 g/kg. Multiple linear regression analysis was used to express the ME values of fats as functions of the parameters measured (moisture, gross energy, impurities, unsaponifiables, non eluted material, free fatty acid content, unsaturated: saturated ratio, peroxide value, TBA test).

3. The ME of the fat products lay in the range 12.62 to 24.35 MJ/kg, and 29.26 MJ/kg for refined sunflower oil. Free fatty acid content of the fats was shown to be a poor predictor of their ME values, whereas non eluted material (NEM) of the fat products showed a good correlation with their ME. A regression equation could be derived (R² = 0.6548; SEE = 2–0064) with the unsaturated: saturated ratio (U:S) and NEM. An ME prediction equation based on the U:S, NEM and unsaponifiable content is also proposed (R² = 0–7168; SEE= 1.9058).  相似文献   

Effects of cultivar,pelleting and enzyme addition on nutritive value of barley in poultry diets     

M. Francesch  A. M. Perez‐Vendrell  E. Esteve‐Garcia  J. Brufau 《British poultry science》1994,35(2):259-272

1. The effect of pelleting process and Trichoderma viride enzymes (TVE) addition on apparent metabolisable energy, corrected for nitrogen balance (AMEn) and on productive value of practical diets containing 40 and 45% of three different barley cultivars and one wheat were studied in poultry.

2. The effect of the pelleting process on AMEn was inconsistent and was dependent on the cereal included and the addition of enzyme.

3. The growth trial showed a significant effect of enzyme addition to pelleted diets over the whole growth period (0 to 42 d). Addition of TVE improved weight gain and food efficiency by 1.3% and 2.9%, respectively and decreased food intake by 1.6% between 0 and 22 d. In the finisher period (23 to 42 d) TVE improved efficiency by 2.8% and reduced food intake by 2.9%.

4. The incidence of sticky droppings was related to the viscosity of barley used, and enzyme supplementation reduced it. Both pelleting and enzyme addition increased dry matter content of excreta.

5. At the end of the experiment, 14 animals per treatment were slaughtered and carcass yield, viscera weight and abdominal fat were determined.  相似文献   

Rapeseed meal and egg taint: Treatment of rapeseed meal to reduce tainting potential     

G. R. Fenwick  A. Hobson‐Frohock  D. G. Land  R.F. Curtis 《British poultry science》1979,20(3):323-329

1. Treatment of rapeseed meal with calcium hydroxide suspension decreased the sinapine content by up to 90%. Smaller decreases were obtained by autolysis, steaming and treatment with ammonia.

2. When this treated meal was fed to susceptible ("tainting") hens the concentration of trimethylamine in the eggs was decreased to much less than that required to cause taint.  相似文献   

水稻白叶枯病杂草带菌和传病的研究     

段永嘉  王英祥  陆晓东 《植物保护学报》1979,6(3):19-23

水稻白叶枯病自发现到现在已有90年的历史。由于发生地区广泛,为害严重,各国对此病曾做了大量研究。日本对它已研究了半个多世纪,我国也有二十多年的研究经历。但对其侵染来源和传播途径,仍有不同看法。我国最初认为种子传病是首要的。但在病区单抓种子处理还不能收到预期效果,又认为病稻草是病区次年的主要菌源。近年来,又发现在严格处理病革、病种子的情况下,仍然发病,故怀疑除上述两种传播途径外,还有其它传播途径。关于杂草传病问题,日本已进行了多年的研究,但和我国国内一样,对杂草带菌传病问题,意见很不一致。我们认为对这一传播途径有彻底弄清的必要,它不仅关系到一个病的侵染循环问题,而且直接关系到对白叶枯病的彻底防治。如果这一传播途径确实存在,我们若不承认它,在防治上就会出现大的漏洞。如果白叶枯病确与杂草无关,盲目地采用相应的措施,也是多余而毫无意义的。这次试验是采用较直接的“离心浓缩针刺接种法”,其结果:第一年证实有马唐等六种杂草、黄豆和水稻根部能够带菌;第二年证实有车前等三种杂草和水稻根不仅带菌,而且可越冬并存活到次年五月;第三年又证实在不同地区有马唐,狗牙根等四种杂草能够带菌越冬,并存活到次年五月中旬。另外,用病区杂草和水稻健苗混栽,结果稻苗上发病,而对照的不发病。通过三年来的试验研究,证实有数种杂草的根茎部不仅带菌,而且能传病。  相似文献   

Effect of injecting amino acids into the egg on embryonic and subsequent growth in the domestic fowl     

W. K. Al‐Murrani 《British poultry science》1982,23(2):171-174

1. The growing embryo uses about 1% of the total protein available in the egg during the first week of incubation.

2. Injecting the growing embryo with amino acids equivalent to the amount of protein used resulted in higher weight of chicks at all stages up to 56 d.  相似文献   

The use of air‐coolers in broiler houses under subtropical conditions in Iraq     

Ridha J. Al‐Zujajy  H. El‐Hammady  M. A. Abdulla 《British poultry science》1978,19(6):731-735

1. Under summer conditions in north Iraq, 2 000 chicks were reared for 56 d in two broiler houses. One house was provided with two air‐coolers. The birds were housed at densities of eight to 16 birds/m².

2. Differences in weight gain between birds in cooled and uncooled houses ranged from 101.5 g at eight birds/m² to 385 g at 16 birds/m². Food consumption increased gradually with increasing bird density. Food conversion efficiency, meat yield and carcass conformation were much better in the cooled house than under conventional conditions.

3. The financial return/m² ranged from 2.30 to 4.51 ID¹ in the cooled house, compared with 2.01 to 2.77 ID in the uncooled house at different floor densities.  相似文献