山东小尾寒羊研究概况

介绍了山东小尾寒羊的研究概况 ,主要内容包括该品种的繁殖性能、屠宰性能、杂交利用等方面的最新研究成果 ,比较全面地阐述了山东小尾寒羊的种质特性。     

引入青海的南德温牛适应性评价与利用

通过对引入青海的南德温牛改良青海本地黄牛效果的调研与测定，并将其有关性状同省内黄牛后代相比较，给在青海这个特殊环境下生长的南杂F1牛作以适当的适应性评价，为种畜管理部门和杂交利用单位提供一些参考性意见，为南德温牛在青藏高厅进一步发展和利用提出建议。     

搞好晋南牛选育保种,促进商品化生产发展

本文首先介绍了晋南牛在运城地区的发展现状。接着对搞好晋南牛选育保种所做的具体工作作了阐述，对晋南牛杂交改良效果作了总结；对运城地区规模养牛的现状给予了积极评价；最后提出了今后对晋南牛实施综合开放利用做的具体工作。     

跨越计划对高档牛肉生产的指导意义

根据跨越计划执行效果，肉牛杂交配套系宜采用三元杂交；育肥实践上，宜改三个月的短期育肥为更长时间，才能生产出更多高档牛肉，改变高档牛依靠进口的局面。     

夏南牛新品种培育技术研究

夏南牛培育项目始于1986年。夏南牛是以夏洛来牛为父本,以南阳牛为母本,应用人工授精技术,采用杂交创新、横交固定和自群繁育三阶段开放式育种方法,根据血统、外貌、体重综合选择,以体重为主,同时考虑早熟性,经过21年严格的选种选育,育成的含夏洛来牛血37.5%的肉用牛新品种。通过中间试验、育肥试验、屠宰试验,夏南牛表现出良好的肉用特征,生长发育速度、屠宰率、净肉率、肉品质等方面明显优于南阳牛。本文总结出了一套适合我国国情的肉牛新品种育种成功经验。     

Crossbreeding experiment with beef and dual-purpose sire breeds on Danish dairy cows

The experimental design and objectives are outlined for a crossbreeding experiment with European beef breeds as sire breeds and RDM (Danish Red), SDM (Black Pied Danish) and Danish Jersey as dam breeds.Results from a calving survey of 1006 single calvings are presented. Gestation length, birth weight and calving performance were strongly influenced by breed of sire, breed of dam and sex of calf. The variation in gestation length seemed to have only a slight effect on birth weight. The variation in birth weight had a strong effect on calving performance.The ranking of the sire breeds in descending order according to the frequency of unasisted calvings (which varied from 70 to 26 percent) was as follows: Hereford, Limousin, Danish Red and White Cattle, Simmental, Blonde d'Aquitaine, Chianina, Charolais and Romagnola.     

Economic efficiency of Japanese Black cattle selection schemes utilizing crossbreeding with the Holstein breed

The economic efficiency of Japanese Black (JB) cattle selection schemes utilizing crossbreeding with the Holstein (H) breed was evaluated in the context of maximizing profitability. Selection schemes were defined that differed in the records available for use as selection criteria. The selection schemes were assessed based on profitability per cow in the JB cattle population. Within each selection scheme, two terminal crossbreeding systems were considered: two‐way crossbreeding without backcrossing (F₁ system) and two‐way crossbreeding with backcrossing (F₁ cross system). The impact on profitability of varying number of sires selected per year and the proportion of H cows that were inseminated by JB semen and of F₁ females that are retained for replacement was examined for all selection schemes. Utilizing crossbreeding with the H breed was less profitable than purebreeding of the JB. Profitability was higher in the F₁ system than in the F₁ cross system in all selection schemes. Profitability was influenced more by changes in the number of sires selected per year than by the proportion H cows that were inseminated by JB semen and of F₁ females that were retained for replacement. Implications of these results for the JB breeding program are discussed.     

岳西黑猪与北京黑猪和巴克夏猪的杂交效果分析

岳西黑猪为安徽省岳西县独有的地方猪品种。文章通过繁殖、胴体、肉质性能的测定和比较分析,综合评价北京黑猪和巴克夏猪与岳西黑猪的杂交效果,筛选可推广的杂交组合模式,为岳西黑猪的杂交利用奠定基础,旨在更好地促进岳西黑猪产业化开发。     

嘉兴黑猪的保种和利用

本文详细介绍了嘉兴黑猪与外国品种的杂交效果以及近年来培育的嘉黑新品系的生产性能，探讨了嘉兴黑猪保种和利用中存在的主要问题，并提出了嘉兴黑猪保种和利用的有效措施，以期引起人们对嘉兴黑猪保种和利用的重视。     

山丹马品种资源的利用现状及展望

在商品生产中,山丹马作为杂交母本或父本除直接利用以外,近年来,又作为基本育种材料,导入了不同比例的其他种公马的血统,与其进行了二元、三元、多元或级进杂交。新品系的选育和推广利用既促进了山丹马遗传资源的保护,也给保种工作带来了挑战。而培育竞技、旅游、休闲娱乐用马不仅将为山丹马遗传资源的利用提供广阔的市场前景,同时也可取得很好的经济效益、生态效益和社会效益,从而实现绿色养马的产业化发展。     

奶牛杂交群体及其遗传评估的模拟研究

为验证在奶牛杂交群体中将品种组成和杂合度作为协变量的遗传评估理论,为奶牛杂交模式选择和杂交群体遗传评估等实际问题提供理论依据,结合我国奶业现状,本研究模拟了在低产荷斯坦牛群引入法系蒙贝利亚牛、德系西门塔尔牛进行杂交,采用随机交配和三品种轮回杂交模式、群体世代重叠17年的繁育过程.群体杂合度在第7年后趋于平衡,轮回杂交模式的群体杂合度高于随机交配.经过杂交,原中低产荷斯坦牛群体在产奶性能、生长性能方面都有进展,轮回杂交提高幅度相对略高.此外,利用品种效应和杂合度效应剖分杂种优势,采用单性状和多性状动物模型对模拟群体进行遗传评估,效果基本一致,都可以很好地用于杂交群体的遗传评估.结果表明,对荷斯坦牛中低产群体进行杂交,可实现生产性能和效益的提高,回归模型可用于多元群体的遗传评估.     

建立皮埃蒙特牛杂交改良示范推广基地的设想

本文介绍了南阳市利用优质国外肉牛品种—皮埃蒙特牛改良南阳牛的情况及效果,提出了在南阳市建立皮埃蒙特牛杂交改良示范推广基地的设想,基地发展前景十分广阔,真正能起到示范带动作用。     

Estimation of additive and non-additive genetic parameters for reproduction, growth and survival traits in crosses between the Moroccan D'man and Timahdite sheep breeds

Genetic breed differences, heterosis, recombination loss, and heritability for reproduction traits, lamb survival and growth traits to 90 days of age were estimated from crossing D'man and Timahdite Moroccan breeds. The crossbreeding parameters were fitted as covariates in the model of analysis. The REML method was used to estimate (co)variance components using an animal model. The first estimation of crossbreeding effects for Timahdite and D'man breeds shows that breed differences in litter traits are mainly of maternal genetic origin: +1.04 lambs, +1.88 kg, +0.60 lambs, and +2.23 kg in favour of D'man breed for litter size at lambing, litter weight at lambing, litter size at weaning, and litter weight at 90 days, respectively. The breed differences in lamb growth and survival are also of maternal genetic origin for the majority of traits studied, but in favour of the Timahdite breed: +3.48 kg, +45 g day⁻¹ and +0.19 lambs for weight at 90 days, for average daily gain between 30 and 90 days of age, and for lamb survival to 90 days, respectively. The D'man direct genetic effect was low and negative for survival and birth weight of lambs during the first month of life. All traits studied showed positive heterosis effects. Recombination loss effects were not significant. Therefore, crossbreeding of Timahdite with D'man breeds of sheep can result in an improved efficiency of production of saleable lambs. Heritability estimates were medium for litter size but low for the other reproduction traits. Direct heritabilities were low for body weights and lamb survival at 90 days and the corresponding maternal heritabilities showed, however, low to moderate estimates. For litter traits, the estimates of genetic and phenotypic correlations were positive and particularly high for genetic correlations.     

高档肉牛生产繁育基地的建立与犊牛培育

文章从肉牛品种选择、杂交改良、科学饲养及管理等方面论述了高档肉牛生产繁育基地的建立,旨在给行业生产提供技术资料。     

渤海黑牛种群现状及其保种利用问题

渤海黑牛是肉役兼用的优良品种,被列为我国受保护的地方良种。本文重点介绍了渤海黑牛种群现状及存在的问题,并对渤海黑牛的保种途径与利用措施以及渤海黑牛的杂交改良与开发利用进行了归纳总结,认为以我国优良地方黄牛品种为基础,选育具有中国特色的黄牛肉用新品种,是我国肉牛保种及提高生产效益的必由之路,这对其它地方品种的保护与利用具有一定的借鉴意义。     

Mini review: breeding Awassi and Assaf sheep for diverse management conditions

The Local Awassi, a triple-purpose breed for meat, milk, and carpet–wool production, is a low-prolific, hardy breed that is well adapted to the unfavorable conditions of the Middle East, where it is managed under traditionally extensive to semi-extensive conditions. Breeding work with the Awassi has included within-breed selection, crossbreeding, and gene introgression. Those efforts resulted in a variety of Awassi-derived genotypes that successfully occupy semi-intensive as well as intensive production systems. Thus, within-breed selection resulted in development of the “Improved Awassi”—a dairy-type Awassi strain which, under intensive management, produces over 500 l milk/ewe annually; crossbreeding with the East Friesian breed led to the development of the Assaf dairy breed, which exceeds the Improved Awassi in prolificacy and in year-round breeding activity, and introgression of the B allele of the FecB locus into the Awassi and Assaf breeds resulted in the formation of the prolific Afec Awassi and Afec Assaf strains, with prolificacies of 1.9 and 2.5 lambs born per ewe lambing, respectively. Advanced molecular genetics tools have enabled a better understanding of how the Awassi breed was formed during domestication and have uncovered differences in its genetic structure compared to other breeds. Implementing large-scale selection schemes that implement emerging new information on the sheep genome, overcoming threats of inbreeding depression, and further breeding for high uterine capacity are the new breeding goals for the Awassi, Assaf, and their derivatives.     

Fat-tailed sheep production systems in the Khyber Pakhtunkhwa Province of Pakistan

Balkhi, Michni and Hashtnagri populations are the three fat-tailed phenotypes native to Khyber Pakhtunkhwa Province of Pakistan, harbouring the central valley. Their distribution, breeding trend and performances were evaluated through a survey using a pre-tested questionnaire during August, 2008. Out of the total populations, 70.7% were mixed flocks and 5.8%, 3.1% and 9.2% were purebred flocks belonging to Balkhi, Hashtnagri and Michni populations, respectively. Sheep flocks were reared under three different production systems, i.e. sedentary, transhumant and nomadic. Nomads keep Balkhi and are sole responsible for their development as a mutton breed. They practise autumn breeding only, for which they select the heaviest ram/s available within the community. Sedentary and transhumant shepherds had mixed flock, who were constantly replacing their native breed stock, i.e. Michni and Hashtnagri through outcrossing with Balkhi. The size of Balkhi and Michni populations warrants no immediate threat to their existence and diversity. However, in case of increased popularity of crossbreeding, Michni could pose threats of extinction. Hashtnagri on the other hand can be declared as breed at risk. Age at first lambing was significantly lower in Hashtnagri ewes, followed by Michni, crossbred and Balkhi. Hashtnagri ewes outperformed other populations in lambing twice per annum.     

南阳牛导入夏洛来培育肉用新品系项目进展

为了提高南阳牛的肉用性能,本项目通过导入夏洛来肉牛外血,采用杂交创新、正反回交和横交固定三阶段开放式育种方法,目前已进入大面积横交和扩群繁育阶段。结果表明,横交牛早熟性强,产肉性能优于南阳牛,肌肉嫩度较好,可用于生产高档牛肉。2005年10月底,项目区共存栏横交牛12 760头,选留横交公牛16头,组建核心牛群5 000多头,横交固定达二代以上。横交牛已具备肉用牛特征,为最终培育南阳牛肉用新品系奠定了坚实基础。     

Evaluation of mating systems involving five breeds for integrated beef production systems: III. Integrated system.

Angus (A), Charolais (C), Hereford (H), Limousin (L), and Simmental (S) breeds were included in deterministic computer models simulating integrated cow-calf-feedlot production systems. Three mating systems were used: pure-breeding and two-and three-breed rotational crossbreeding. Breed information was taken from the literature. Herd sizes were unrestricted; however, 100 heifers were saved as replacements. Cows were removed for reproductive failure, age (greater than 10.5 yr), or death. Calves produced in the cow-calf segment were fed in a custom feedlot to four slaughter end points: 440 d, 457 d, 288-kg carcass weight, and low Choice. All animals were fed to requirements. Cull cows were slaughtered after weaning. Biological and economic efficiencies improved with crossbreeding; however, rankings of breed combinations depended on how efficiencies were measured (weight, lean, or value basis). Among purebreds, reproductive performance had a large influence on breed rankings at age and weight end points, whereas feedlot performance was important at the low Choice end point. Crossbred combinations involving British (A or H) and Continental (C or S) breeds were more efficient than other crossbred combinations at all end points. However, choosing specific breed combinations for integrated systems depends on slaughter end points, market end points (weight vs lean), and measures of efficiency (weight, lean, or value basis).     

肉牛繁育存在的问题与对策

在对黑龙江省肉牛繁育中存在的诸如盲目引进国外肉牛品种与当地品种进行杂交改良、地方品种保种工作停滞不前致使地方品种面临绝种危机、冷冻精液市场无序竞争、国有龙头企业难以生存等问题进行了深入分析的基础上从五个方面提出了解决问题的对策,为黑龙江省肉牛繁育进一步科学发展提供了科学依据。