不同季节牧草钙磷含量对放牧绵羊血清骨钙素的影响

研究了不同季节牧草钙磷含量对放牧绵羊血清骨钙素、碱性磷酸酶、血清钙、无机磷、血清钙磷比和血清钙磷乘积的影响。结果表明:这些血清指标随季节变化明显,血清骨钙素夏季含量为(2.009±0.888)ng/mL,极显著的低于冬春季(3.974±1.281)ng/mL和秋季(3.279±1.365)ng/mL的含量(P<0.05)。从相关分析中看出,骨钙素与AKP、血钙、无机磷、血钙/磷和血钙磷乘积呈正相关,相关系数分别为0.047、0.546、0.035、0.394、0.489。与牧草钙、磷和钙磷比呈负相关,尤其与牧草钙的相关系数达-0.657(P<0.01)。利用逐步回归的方法得出的骨钙素与牧草钙、血清钙的多元回归方程为:骨钙素=1.813-2.358牧草钙+0.945血清钙(P<0.05)。认为血清骨钙素可以作为反映放牧绵羊钙磷盈缺状况的灵敏指标。     

海西地区人工草地生产布局探讨

海西地区指州辖天峻县、乌兰县、都兰县、德令哈市、格尔木市以及西部大柴旦、冷湖、茫崖三镇,覆含柴达木盆地。畜牧业是海西州支柱产业之一,草地是其发展的基础,畜牧业发展需要人工草地生产支持,科学布局人工草地对于安全高效发展草地畜牧业具有积极重要的现实意义。     

Utilization of soybean meal as an alternative protein source in the Mediterranean yellowtail, Seriola dumerili

The availability of defatted soybean meal as a substitute for fish meal was evaluated in juvenile (450 g on average) yellowtail fed diets containing several levels of soybean meal (from 20 to 50%). After 153 days, liveweight averages were 980, 925, 795 and 670 g for fish fed diets in which fish meal was partially substituted with 20, 30, 40 and 50% soybean meal, and feed conversion ratios were 2.79, 3.09, 4.57 and 6.52, respectively. Regression analysis showed a negative effect of inclusion of soybean, although fish fed diets containing 20% and 30% of soybean did not present statistical differences and grew significantly more, and had a better feed conversion ratio, than fish fed 40 or 50% diets. Likewise, muscle protein level was lower and lipid content was higher in fish fed 20 or 30% soybean. No differences were obtained for protein digestibility coefficients of experimental diets.     

Oestrus detection techniques and insemination strategies in Bos indicus heifers synchronised with norgestomet-oestradiol

SUMMARY Oestrus was synchronised in 57 Bos indicus heifers using norgestometoestradiol and pregnant mare serum gonadotrophin. Oestrus was detected by observations made at six-hourly intervals, using oestrogen-treated and chin-ball harnessed steers, heatmount detectors, tail-paint and visual observation. Heifers were inseminated once at either a fixed time of 49.2 ± 0.4 h (mean ± SE; n = 29) after implant removal or 12.6 ± 1.5 h (n = 28) after oestrus was detected. The mean (± SE) time to the onset of oestrus was 47.1 ± 1.9 h, while 90% of heifers recorded in oestrus were detected within 66 h of implant removal. Heatmount detectors were significantly more efficient at detecting oestrus than chin-ball harnessed steers, tail paint or visual observation (P < 0.001). A higher pregnancy rate was obtained in heifers inseminated after oestrus detection compared with heifers inseminated at a fixed-time (57.1 vs 34.5%; P = 0.043) and a higher pregnancy rate was obtained in heifers classified as easy to inseminate compared with heifers classified as difficult to inseminate (57.8 vs 0%, P < 0.001). We conclude that heatmount detectors are an efficient means of detecting oestrus in synchronised B indicus heifers and that pregnancy rates can be increased when insemination follows oestrus detection compared with a fixed-time insemination regimen.     

工厂化两苗互作育苗麦后机械化移栽棉花的生长发育及产量特点

为了推广与发展麦后移栽棉种植模式,在大田条件下,研究了工厂化两苗互作育苗麦后机械化移栽棉花的生长发育及产量特点.结果表明:营养钵育苗麦后移栽春棉、工厂化两苗互作育苗麦后移栽春棉和夏棉的子棉产量和霜前子棉产量相当.与麦套移栽春棉相比,麦后移栽棉花的生育进程有所推迟,子棉产量降低4.2％～4.7％,霜前花率降低0.9～1.3个百分点;但与麦后直播夏棉相比,麦后移栽棉花显著增产57.3％～58.2％,霜前花率提高约19个百分点;与麦后直播春棉相比,麦后移栽棉花显著增产62.1％～63.0％,霜前花率提高约20个百分点.此外,棉花麦后移栽,有利于小麦全幅播种和机械收获,且小麦产量比套种田小麦增产25％以上(P＜0.05),同时,棉花工厂化两苗互作育苗实现了专业化、商业化和规模化育苗,有利于棉花机械移栽.可见,工厂化两苗互作育苗麦后机械化移栽春棉和夏棉可以取代传统营养钵育苗麦后移栽.     

Determination of the bulk moisture diffusion coefficient for corn starch using an automated water sorption instrument

The bulk moisture diffusion coefficient (Db) is an important physical parameter of food ingredients and systems. However, the traditional method of measuring Db using saturated salt solutions is very time-consuming and cumbersome. New automated water sorption instruments, which can be used to conveniently and precisely control both relative humidity and temperature, provide a faster, more robust method for collecting the data needed for determining Db. Thus, the objectives of this study were to (1) investigate the use of the DVS instrument for collecting the data needed for determining the adsorption (Dba) and desorption (Dbd) bulk moisture diffusion coefficients for dent corn starch as a function of relative humidity and (2) determine the effect of temperature on Dba for dent corn starch at a constant relative humidity. Kinetic water sorption profiles of dent corn starch were obtained at eight relative humidity values ranging from 10 to 80% at 10% intervals at 25 degrees C and at five temperatures, 15, 20, 25, 30, and 35 degrees C, at 50% relative humidity using a DVS instrument. Db was calculated from the kinetic water sorption profiles using the full solution of Fick's second law for the thin slab model, as well as the slope method, a simplification of the full model. The Dba of dent corn starch at 25 degrees C reached a maximum at intermediate relative humidity values, after which Dba decreased due to a change in the moisture diffusion mechanism from vapor to liquid diffusion. The Dbd of dent corn starch at 25 degrees C remained nearly constant as a function of relative humidity. The Dba for dent corn starch increased as temperature increased from 15 to 35 degrees C, with an activation energy of 38.85 +/- 0.433 kJ/mol.