黄土旱塬地紫花苜蓿品种对比试验

对所引进的8个紫花苜蓿品种进行了两年零3个月的对比试验,结果表明,WL323m l、三得利叶茎比在1:1~1:1.2之间,相对较小;WL323m l青干草粗蛋白含量达24.33%,加工高蛋白的草颗粒具有优势;金黄后、三得利、阿尔冈金-Ⅱ、捷达产量相对较高,无论作为鲜草或青干草生产均适宜大面积种植。     

西藏青稞品质改良的趋势及对策

生态因子、土壤质地、肥力及栽培措施 ,品种品质的遗传特性与生态环境的协调性 ,以及当地青稞的消费状况 ,是西藏青稞生产上不可忽视的问题。青稞生产如何根据生态条件种植适销对路的优质青稞品种 ;建立优质青稞生产基地、集中连片、区域化种植 ;实施优质配套栽培技术 ;优质优价 ,单收、单贮 ,将成为促进西藏农村和农业经济发展的重要途径。     

小麦三个品质性状微量检测方法的应用与评价

为探讨小麦育种中简单、可行和高效的品质选择指标,给小麦品质改良提供借鉴,对蛋白质含量、籽粒硬度和SDS沉淀值在本单位育种中的应用效果进行分析,结果表明籽粒硬度在不同基因型间的变异系数最大,在不同栽培条件和不同年份表现稳定,是有效、可靠的选择指标;SDS沉淀值与蛋白质含量、籽粒硬度均呈极显著正相关,在基因型间的变异较大,可作为一个能反映总体品质水平的选择指标;蛋白质含量在基因型间变异系数小,受环境影响大,用于早代选择效果不理想。品质育种中可根据籽粒硬度和SDS沉淀值进行初步选择。     

黄淮中南部夏大豆新品种选育技术指标量化分析

通过对河南省21年来审定大豆品种的主要特征特性分析,总结出黄淮夏大豆增产的主要原因是分枝数、株荚数的增加;黄淮夏大豆新品种选育的主要指标是有限结荚习性,有效分枝在3～4个,株荚数在50个以上,百粒重在15.0～24.0 g之间,高蛋白、高油或蛋脂双高.     

黄灌区农场管理模式下玉米自交系繁育研究——以甘肃省靖远县寺儿坪农场为例

以甘肃省靖远县寺儿坪农场为例,阐述了在黄灌区农场管理模式下自交系繁育的优势和存在的问题,并提出该模式下生产玉米自交系的对策,为从事玉米自交系繁育人员提供一定的指导意义。     

猪肉品质及其影响因素的研究概况

随着猪肉生产中瘦肉率的提高,以及有害添加剂的饲喂,猪肉品质恶化。而另一方面,人们的保健意识增强,对各种畜禽肉质和风味提出了更高的要求。本文综述了常规肉品质性状,以及品种和营养对它的影响。     

中国对虾亲虾反季节培育技术的初步研究

2001年11月18～28日自日照水产研究所等几处中国对虾越冬室筛选性腺有一定发育并已交尾的雌虾36尾，并采用光线控制、水温控制、饵料调节、性腺催熟等方法，促使对虾性腺快速发育。至2002年1月10日从性腺培育成熟的对虾亲虾中选取3尾，使用0．5m。塑料桶进行苗种培育。实验结果表明，中国对虾不经过常规的越冬管理，只要具备对虾亲虾发育的环境条件，在一定时间内性腺即可发育成熟．并能进行正常苗种培育。     

Heart disease as a cause of death in insured Swedish dogs younger than 10 years of age

BACKGROUND: Population-based information on disease occurrence is paramount in clinical decision making and in designing preventative measures, but such information is scarce. HYPOTHESIS: The risk of cardiac death is higher in certain breeds and mortality varies by age and sex. DOGS: Dogs that were life insured by an animal insurance company between 1995 and 2002. METHODS: The mortality pattern for heart disease in insured dogs up to 10 years of age was studied. The influences of sex, age, breed, month, and geographic location were investigated by means of incidence rates, proportions, and survival proportions. Cox proportional hazards regression was used to model time to heart disease. RESULTS: 405,376 dogs contributed to a denominator of 1,431,933 dog-years at risk (DYAR) and 3,049 dogs had been assigned a cardiac-related diagnosis as cause of death. The cardiac-related mortality for dogs <10 years of age, was 21.3 deaths per 10,000 DYAR. This mortality in males and females was 27.3 deaths and 15.4 deaths per 10,000 DYAR, respectively. Twelve of 54 breeds had a point estimate above the overall rate. The 3 breeds with the highest point estimates were: Irish Wolfhounds, Cavalier King Charles Spaniels, and Great Danes (rates of 356, 247, and 179 deaths per 10,000 DYAR, respectively). CONCLUSIONS AND CLINICAL IMPORTANCE: Breed, age, and sex affect cardiac mortality in certain breeds of dogs, but no effects of month and geographic location were identified. These findings can assist clinicians in establishing diagnoses, and can assist breeders in defining priorities for preventative measures.     

Effect of breed on fatty acid composition and stearoyl-CoA desaturase protein expression in the Semimembranosus muscle and subcutaneous adipose tissue of cattle

The present study investigated (i) the effect of breed on the expression of stearoyl-CoA desaturase (SCD) protein and fatty acid composition in Semimembranosus muscle and subcutaneous adipose tissue of beef cattle and (ii) the relationship between SCD expression, cis-9, trans-11 conjugated linoleic acid (CLA) content, and monounsaturated fatty acid (MUFA) level. The study was conducted on the following breeds: Longhorn (L), Charolais cross with Holstein–Friesian (CX), Hereford (H), Belted Galloway (BG) and Beef Shorthorn (BS). Significant breed differences in the total fatty acid content, saturated fatty acid (SFA) level, MUFA and n−3 PUFA content were observed in subcutaneous adipose tissue but not in muscle. In the case of CLA, the breed differences were observed in both muscle and subcutaneous adipose tissue, with the highest level in L and the lowest level in H. In the case of subcutaneous adipose tissue, the breed with the highest CLA content (L) also had the highest SCD protein expression. The breed-specific pattern of SCD expression in subcutaneous adipose tissue was similar to the breed-specific pattern of one of the products of an SCD-catalysed reaction, C16:1 (BS < BG < H < CX < L). It has been concluded that (i) the mechanisms regulating SCD protein expression and CLA level in beef cattle are tissue-specific; (ii) breed-specific variations in SCD expression might contribute to breed variations in MUFA and CLA content in subcutaneous adipose tissue but not in Semimembranosus muscle.     

Estimation of some productive and reproductive effects on longevity of beef cows using survival analysis

Longevity of beef cows defined as the length of productive life from first calving to culling was estimated in this study. Data from 1800 cows belonging to Hereford, Angus, Simmental, Charolais, Limousin and Blonde d' Aquitaine breeds were analysed using survival method. The results indicate effects of breed, calving season, and calving difficulty on longevity (P < 0.05); however, herd, age of the cow at first calving, sex and weaning weight of their calves did not affect (P > 0.05) the length of productive life. Hereford had significantly greater (10.3 years) estimated length of productive life than Angus (8.1 years), Simmental (7.9 years), and Charolais (7.1 years), which had similar estimated longevity. Limousin (5.9 years) and Blonde d' Aquitaine (5.2 years) were similar in estimated longevity, but less than the other breeds studied. Cows that calved first in spring or summer were estimated to have longer productive life (7.2 years and 9.9 years) and less risk of early culling than those calving in autumn (5.7 years) and in winter (5.1 years). Longer productive life (6.2 years) was estimated across breeds for cows calving without assistance or with a little assistance (6.9 years) compared to those needing veterinary assistance (2.8 years) or having stillbirth (4.6 years). The results highlight that breed, calving season and calving difficulty of beef cows may have important effects on length of productive life. Special attention should be devoted to these effects.