Colostrum production by ewes and the amounts ingested by lambs

Studies involving 49 ewes which were well nourished during the last eight weeks of pregnancy indicated that ewe weight loss during pregnancy and lamb birth weights followed the recognised pattern and were within acceptable "normal" limits. Colostrum production ranged from 1238 to 4593 g per ewe during the 48 h following the first suckling and there was evidence that production levels were related to demand by the lambs. Colostrum consumption by individual lambs was related to litter size. The smaller the litter size the greater was the amount ingested during the first 48 h of life. No clear relationship was established between the amount of colostrum consumed and the level of immunoglobulin in a lamb's circulation. Possible reasons for this are discussed.     

以改革为动力 促进我场蚕种生产的发展

阳山蚕种场始建于1985年,在省丝绸集团公司的领导下,在各级有关部门和兄弟单位的支持下,走过了15个春秋,为广东和粤北的蚕桑发展作出了应有的贡献。     

利用正交试验设计研究葡萄糖处理豆粕对奶牛过瘤胃蛋白的影响

以3头装有永久性瘤胃瘘管的中国荷斯坦牛为试验动物,采用尼龙袋法研究在不同因素下葡萄糖处理豆粕,在奶牛瘤胃内不同时间点DM、CP消失率及其有效降解率的作用效果。结果表明:在不同时间点,提高葡萄糖添加量可使DM、CP消失率逐渐降低,所有试验组与未处理组差异均显著(P0.05),葡萄糖添加量、加热温度、加热时间、含水量四个因素均对蛋白质降解率影响显著,四个因素的影响顺序为:加热温度加热时间葡萄糖添加量含水量;随着加热温度升高、加热时间的延长、葡萄糖添加量的增加,豆粕DM降解率与瘤胃蛋白降解率都逐渐下降。     

纳滤技术生产高纯度低聚果糖的研究

对采用纳滤技术生产高纯度低聚果糖进行了研究。研究表明，膜的透过通量受温度、料液浓度、操作压力等参数的影响。通过试验确定了最佳操作条件，使低聚果糖纯度FOS≥95％。     

Factors affecting the retention of calcium by the chick

The addition of 5 or 10% tallow to a broiler diet containing 0.9% calcium reduced the retention of that element, although not sufficiently to cause a deficiency. Supplementation of the diets with vitamin D₃ above the minimum requirement level did not improve the retention of calcium in the added fat diets.     

通过营养调控降低畜禽排泄物对环境的污染

随着畜牧业生产规模的不断扩大和集约化程度的不断提高,畜禽排泄物对环境的污染已受到普遍重视。为获得高生产性能而给畜禽提供过量营养是造成环境污染的主要原因之一,通过营养调控来最大限度地提高动物对营养物质的利用率是解决问题的重要手段。     

与时俱进 开拓进取 走创名牌之路

广东省丝绸集团成立50周年了,伴随着发展过程中出现的风风雨雨,如今她已发展成为贸工农一体化的大企业集团公司,作为其中的一员——德庆县蚕种场也已在市场摸爬打滚中长出了丰满的羽翼,准备展翅高飞了。德庆蚕种场成立于1963年,回顾40多年的发展历程,大致可以分为三个历     

Comparison of the stressfulness of harvesting broiler chickens by machine and by hand

The procedures of manual and machine catching acted as short-term stressors, and induced a state of fear in 8-week-old broiler chickens. The heart rate of birds caught by both methods rose to similar high values but that of birds caught by machine returned to near normal rates more quickly, suggesting that they were less stressed. The duration of tonic immobility, a response which increases with fearfulness, was much longer in manually-caught birds. These results suggest that stress could be reduced and welfare improved by catching and picking up broiler chickens by a carefully designed machine, rather than by hand.     

Inhibition of Dermatophilus congolensis by substances produced by bacteria found on the skin

Bacteria, isolated from the skins of clinically normal sheep, were tested for inhibitory activity against Dermatophilus congolensis grown in vitro. Out of 85 bacterial isolates, 19, mainly Bacillus spp., showed zones of inhibition when grown together with D. congolensis. The inhibitory activity was shown to be due to the metabolites released by the bacteria.     

Assessment of the Long-Term Viability of the Myxospores of Myxobolus cerebralis as Determined by Production of the Actinospores by Tubifex tubifex

While whirling disease was first observed in Rainbow Trout Oncorhynchus mykiss in 1893, the complete life cycle of Myxobolus cerebralis (Mc), the causative agent of the disease, was not understood until 1984, when it was shown to involve two obligate hosts, a salmonid fish and the aquatic oligochaete Tubifex tubifex (Tt). The viability of the triactinomyxon (TAM) actinospores produced by Tt has been well studied, and is known to be temperature dependent and measured in days and weeks. Assertions that Mc myxospores produced by infected fish remain viable for years or even decades were made during the mid-20th century, decades before the Mc life cycle was described. Moreover, the duration of myxospore viability has not been well studied since the life cycle was elucidated. In a series of time-delay treatments, we assessed the long-term viability of Mc myxospores by exposure to Mc-susceptible Tt oligochaetes and quantified TAM production. As the time delay between inoculation and incubation of Mc myxospores in sand and water and exposure to Tt oligochaetes increased, TAM production decreased exponentially. Production among the 15-d time-delay replicates was reduced 74.7% compared with the 0-d treatment. Likewise, total TAM production was reduced 94.5, 99.4, and 99.9%, respectively, in the 90-, 120-, and 180-d time-delay treatments. Linear regression analysis of our data and the absence of TAM production among replicates of Mc myxospores held at 5°C for 365 d prior to exposure to Mc-susceptible Tt oligochaetes indicate that the long-term viability of Mc myxospores is less than 1 year under the conditions of this study.

Received May 14, 2014; accepted September 27, 2014     

高校教学改革思考——以结果为导向转变为以过程为导向

目前,我国的高校教学普遍以结果为导向。以结果为导向的教学易导致高校师生以应试为目的而消极应付教学的浮躁风气,改革为以过程为导向更为科学。改革的重要方面在于高校的考评制度改革和因材施教的重视。具体的,高校教学课程改革需要高校教师开展课程设计,创新教学模式,兼顾课程教学的基础性、专业性和通识性。     

辐照灭菌的效果研究

利用60Co r射线对细菌的杀灭作用,采用不同的辐照剂量对高免卵黄液及鸭肝炎血清中大肠杆菌杀灭效果进行研究,同时测定卵黄液ND、IBD的抗体效价.结果显示:辐照剂量在3KGY时即可完全杀灭卵黄液及鸭肝炎血清中的大肠杆菌,对卵黄液抗体效价则无明显影响,但最高辐照剂量不能超过12KGY.