The effect of quality of grass and maize silage on the intake and performance of beef cattle

A study was undertaken to evaluate the effects of incorporating high (HMS) and low (LMS) maturity maize silages into diets based on low (LGS) and high (HGS) feed value grass silages offered to beef cattle. Seventy-two continental cross-bred steers were used in a 14-week continuous design, randomised block experiment. The six treatments were arranged as a 2 × 3 factorial design incorporating the LGS and HGS offered as the sole forage, along with each of the two grass silages offered in a 60:40 ratio (DM basis) with the HMS and LMS. All diets were supplemented with 3 kg/head/day concentrates. Total daily DM and metabolisable energy intakes were higher (P < 0.001) for diets based on HGS compared to those based on LGS. Intakes were similar (P > 0.05) between diets containing LMS and HMS, both of which were higher (P < 0.001) than diets containing grass silage as the sole forage. Highest DM intakes were recorded with a mixture of HGS and HMS (P < 0.05 or greater). Cattle offered diets containing HGS had higher live-weight gain (P < 0.05), final live weight, carcass gain and carcass weight (P < 0.001) than those offered diets containing LGS. Feed conversion efficiency, assessed on a carcass gain basis, was poorer (P < 0.05) with diets containing LGS compared with those containing HGS, though differences between diets containing either LMS or HMS and GS as the sole forage were not significant (P > 0.05).     

动物应激的研究进展

对动物应激的研究已有几十年,但有关应激的基础理论体系仍不健全,对于应激的概念及其应用也有很多模糊的地方,致使很多时候人们对应激研究的结果不能进行准确解释。本文对应激的概念、应激的一般反应及应激反应的机理等几个方面进行了综述,希望能引起人们对有关应激理论的思考。     

Considerations on ethics and animal welfare in extensive pig production: Breeding and fattening Iberian pigs

The extensive pig production in Spain is traditionally characterised by: the use of the Iberian pig, an autochthonous breed perfectly integrated into the environment in which they have developed; a long duration of the productive cycle for about 23–24 months; a high level of animal welfare level, specially in the fattening process with freedom of movement and feeding base on natural sources: acorns and grass, and an equilibrated “dehesa” agro-forestry system where this activity has been developed. Nowadays, the introduction of more intensificated methods due to the increasing demand led to important changes, such as: the shortening of the productive cycle (10–12 months); freeing from the territorial base; changes during the fattening period, fattening with mixed feed and less animal freedom. All these facts may implicate a loss of the animal welfare condition. These circumstances lead us to question it from an ethical point of view.     

动物科学专业本科人才培养目标之我见

动物科学专业本科人才培养目标是确定动物科学专业本科课程教学方案的依据,是培养什么质量的动物科学专业本科人才的指导思想。动物科学专业的人才培养目标应包含如下几个重要方面。首先,动物科学专业人才培养目标应着眼于人文精神和合作精神的培养。其二,应注重基础课的教学,使学生获得终生学习的能力。其三,应促进学生的主动性思维,而不是让学生被动地接受知识的传授。其四,应提高学生的实践动手能力。最后,应在本科教学阶段继续提高动物科学专业本科生的语言技能。本文对如上方面逐一进行了阐述。     

山西省畜牧业可持续发展途径研究

山西省畜牧业可持续发展 ,应改变依靠粮食饲养的精料型农区畜牧业发展道路 ,充分利用和发挥本省草地和农作物秸秆资源丰富的优势 ,以大中市场和中长期市场需求为导向 ,走以草食动物为主的节粮型的农牧区畜牧业发展途径 ,并采取有效措施 ,以促进畜牧业沿着稳定、持续方向发展     

我国动物营养科学百年发展的影响因素分析

对近百年来影响我国动物营养学发展的主要因素进行了总结，分析了我国动物营养学的发展历史。     

“Do Not Let the Grange Die!” Michigan Grangers' Struggle for Continued Relevance in the Twenty-First Century

ABSTRACT

The Grange was founded during a time when farmers were the majority of the population and secrecy was a means of survival. More than one hundred thirty-five years later, those characteristics are still strongly associated with it. Yet there is a growing consciousness among many members that the Grange has to become better at promoting itself among nontraditional constituencies-or it will die. This article explores the Grange experiences of five members. All have been profoundly affected by their membership. All are struggling with the need to reconcile loyalty to tradition with the need to change and adapt. In sharing their thoughts and feelings, the study has the opportunity to consider what the Grange's past was, what its present is, and what its future may become.     

Effect of suckling intensity on human growth hormone binding, biochemical composition and histological characteristics of ovine mammary glands

Suckling both, or only one contralateral mammary gland during 15 days postpartum was utilized to study lactogenic hormone binding to mammary microsomal membranes and quantitative mammary morphology in ewes. Binding of radiolabeled human growth hormone was specific for lactogenic hormones. Non-radiolabeled human growth hormone, ovine and bovine prolactin and human placental lactogen effectively competed with radiolabeled human growth hormone for binding sites but ovine and bovine growth hormone were completely ineffective. Specific binding of radiolabeled human growth hormone to 600 μg of membrane protein averaged 23 ± 3% in all lactating glands. Neither days postpartum nor treatment of contralateral mammary glands substantially altered hormone binding in lactating glands. Specific human growth hormone binding (6 ± 0.5%) in non-suckled glands (15 days postpartum both udder halves) was significantly lower (P<0.01) than in lactating tissue but only a moderate and variable reduction in specific binding was measured in membranes from glands non-suckled for 15 days but contralateral to a suckled gland (14 ± 4%). Specific binding was approximately doubled in assays with 600 compared with 300 μg of membrane protein and the pattern of binding among variously suckled glands was not changed by treatment of membranes with 4 M MgCl₂ prior to assay. Most secretory cells from all lactating glands had rounded, basally displaced nuclei, apical fat globules, secretory vesicles and abundant densely stained basal cytoplasm (ergastoplasm). Alveolar lumenal area was maximal (50% of tissue area) and stromal tissue area was minimal. After 15 days of non-suckling (both udder halves) mammary cells were engorged with lipid, ergastoplasm was reduced and nuclei were irregularly shaped and randomly displaced compared with lactating tissue. In addition, lumenal area was reduced and stromal tissue more evident. Lack of suckling for 5 days had little apparent effect on mammary cytology. Like lactogenic hormone binding, mammary tissue morphology was only moderately altered by 15 days of non-suckling when the remaining gland was suckled. RNA concentration was lowest (2.1 ± 0.3 mg/g) in mammary tissue from ewes in which neither gland was suckled for 15 days postpartum but non-suckling interval had no significant effect when contralateral glands were suckled. DNA concentration was not significantly influenced by suckling treatments. Relative lactogenic hormone binding closely corresponded to changes in cytological and biochemical indices of secretory cell function.     

杜洛克猪遗传性跛行的体尺比较

试验采用96头杜洛克猪,这些猪是用反相选择跛行的方法所建立的两个品系的第7代后裔,测定其前肢的尺骨长,尺宽,足长和体长是否有差异。品系分为跛行组和健康组,后者表示在前肢结构上发育良好。所有猪都在二个特定日龄测定,平均117日龄和159日龄,并在每圈猪平均体重达到95kg时进行第三次测量,结束试验。资料用变量分析,混合方程包括品系、重复批次、饲料和性别的影响,并以体重或日龄作协方差分析。健康组猪比跛行组猪足长较长(P<0.01),在117日龄大7％,159日龄大14％,在试验结束时大30％。健康组猪的足宽则几乎和跛行组相等。对不同程度跛行选择的影响也表现在猪的体形方面,健康组猪比跛行组猪在159日龄时体长和尺骨长相对较短,在达到上市体重时体长轻短。对不同程度跛行的选择已使社洛克猪的结构发生了许多变化。     

肉鹅的多态性DNA分子标记及其与屠宰性状的相关性研究

应用随机扩增多态DNA(RAPD)技术分析鹅群的分子标记与屠宰性状的相关性。结果表明 ,从 4 0条随机引物中所筛选出的 14条引物 ,在 5 6日龄的四川白鹅与天府肉鹅两群体中扩增产物的多态率分别为 93.10 %和91.38%。两鹅群中具有共同的标记H0 30 7对活重、屠体重和全净膛重的影响显著 ;具共同的互作标记组合对特定性状有显著效应 :H0 70 2与G14 0 2的互作对活重、H190 2与H190 8的互作对翅重有显著效应。