甘南牦牛杂交改良现状与措施

甘南牦牛应突出肉用价值,把肉当作主攻方向,作为主导支柱产品。开展牦牛与普通牛的种间杂交,是提高牦牛业生产水平和经济效益的重要途径。在二元杂交试验中,若杂交目的主要以生产肉或提高役力,改良牛的父本,应选择短角牛、夏洛来牛、西门塔尔牛、海福特等肉乳兼用和肉用良种牛,具有明显杂优效果;若杂交的目的主要是生产牛奶和酥油,则父本以黑白花奶牛等与牦牛交配产生黑犏杂一代的组合为最佳;若杂交的目的主要是奶肉兼用,则一代奶用二代肉用。甘南地区犏牛繁殖的主要目的是产奶。因此,牦牛种间杂交育种的主要方法是采用良种牛冻精(娟姗牛等)与母牦牛进行人工授精等方法生产良种犏雌牛。     

Optimum use of milk in traditionally managed cattle herds in the tropics

In traditional cattle systems in the tropics, the milk produced is generally shared between the calf and the cattle keeper. This literature review evaluates the socio-economic aspects related to milk production and milk use in traditional cattle systems and identifies the best strategies of milk allocation in order to improve food security and maximise income. The available literature indicates that milk, in terms of economic, social and subsistence value, is more valuable than meat. Thus, under the conditions that characterise traditional cattle systems in the tropics, it is appropriate to have a higher milk offtake at the expense of calf growth. This review also found that certain management practices, such as restricted suckling, can be useful to minimise mortality of calves, while improving milk offtake for human consumption.     

试论平原农区乳肉兼用牛的发展

 基于牛的饲料转化率分析了发展兼用牛的意义,论文从牛奶收集条件和基础母牛资源的角度论述了平原农区发展兼用牛的可行性,提出了平原农区兼用牛的杂交育种模式,建立西门塔尔牛地方类群配套系,低代西杂牛以乳肉兼用型牛杂交,以及乳肉用交替杂交模式。     

内蒙古三河牛培育历程及进展

内蒙古三河牛是我国自主培育的乳肉兼用型品种,它是呼伦贝尔各族人民一百多年来辛勤劳动的结晶。从1986年育成以来,三河牛以核心家系选育的方式延续严格的保种制度,在呼伦贝尔草原严酷环境中保持良好的生产性能和繁殖力。虽然在近20年不断受到荷斯坦牛等高产品种的挑战,但对当地气候的高度适应性和良好的兼用性让三河牛始终立于不败之地。"十一五"以来,三河牛选育进一步得到国家重视,在原有品种登记和性能测定系统的基础上,修定并发布了新的三河牛品种国家标准,建立了三河牛育种信息数据库,引入奶牛DHI测定体系,强调兼用性的育种目标,吸收国外兼用型品种高水平遗传种质,采用开放式核心群育种体系,不断取得各方面进展。现简述三河牛培育历程,并总结目前的各项进展,与业界同仁分享。     

兼用短角牛改良秦川牛效果研究--眉县短秦一、二代母牛生长发育及体型变化分析(之二)

对短秦F1、F2和本地母牛初生、6、12、18、24月龄体尺、体重进行测定,并对其生长发育强度进行对比分析.结果表明,在农村粗放饲养条件下,F2牛初生6、12月龄体重比本地牛分别增加4.3、37.2、35.6kg,相应提高16.6%、28.2%、17.9%;F1牛18、24月龄比本地牛分别增加30.9、47.8kg,提高11.0%和15.6%,改良牛纠正了本地牛的尖斜尻缺点,且生长发育快,增重效果明显,体躯有向肉乳兼用型发展趋势,若加强断奶后的培育,效果更好.     

Altitude effects on technology and productivity of small bovine farms (milk meat) in Veracruz (Gulf of Mexico)

The dual-purpose bovine system represents 98.4% of the bovine livestock of Veracruz, the main cattle-producing state of Mexico. This system supplies calves to meat companies, a sector in which Veracruz has been the national leader in the last decade. The objective of the present study was to analyze the effect of the altitudinal zonation of farms on livestock technology and productivity in a microbasin of the Gulf of Mexico where small farms predominate. Structured interviews were applied to producers located in three altitudinal zones (at average altitudes of 50, 140, and 450 m, respectively, for lower, middle, and upper zones). Sample size was 135 farms having similar land surface (within a range of 15–22 ha). The results indicated multiple differences among farms located in the three zones. Farms in the middle and lower zones presented higher productive indicators than those in the upper zone. Differences in herd structure and management resulted in important differences in productivity, income, and profits in milk and calf production. We concluded from this study that altitudinal zonation in Veracruz had a clear effect on the differentiation of small farms, which are representative of dual-purpose cattle. The upper zone performs cattle activity under conditions with greater disadvantages in the analyzed region.     

农牧交错带是我国牛业突围崛起的战略支撑点

在新西兰乳品冲击下,我国农业生态系统存在着潜伏的危机;在美国规模化养牛模式误导下,我国养牛业陷入误区。由此,提出我国大农业生态系统需要依靠养牛做为支柱,以肉奶两用牛为战略支撑,实现乳肉皆优,肉乳双收,并把农牧交错带确立为我国牛业突围、崛起的战略支撑点。     

Interrelationships of heifer milk production and other biological traits with production efficiency to weaning.

Interrelationships among milk production, dam-calf feed efficiency to weaning, and other biological traits were evaluated on 411 first-calf heifers and their calves. Individual feed intakes were measured in a drylot environment for a 1-yr period until weaning of the first calf. Heifer breed types included crossbred Angus-Hereford, Simmental-Hereford, and Tarentaise-Hereford produced in two-breed rotational crossbreeding systems, F1 Salers-Hereford and straightbred Hereford. Production efficiency was defined as cumulative feed ME consumed by the dam-calf pair during the year divided by calf weaning weight. Milk production potential seemed to be unrelated to cow size, adjusted for breed-group effects. Lactational feed energy was increased for dams of increased milk production potential but not enough to offset the increased production of calf weaning weight in terms of production efficiency. Results indicated that increased levels of milk production of heifers were associated with improved production efficiency to weaning. However, the incremental improvement in efficiency per unit of increased milk was less for each additional unit of milk, within the range evaluated. These results are applicable to first-calf heifers that have not yet reached peak age for maximum milk production.     

Effect of calf death loss on cloned cattle herd derived from somatic cell nuclear transfer: Clones with congenital defects would be removed by the death loss

To increase public understanding on cloned cattle derived from somatic cell nuclear transfer (SCNT), the present review describes the effect of calf death loss on an SCNT cattle herd. The incidence of death loss in SCNT cattle surviving more than 200 days reached the same level as that in conventionally bred cattle. This process could be considered as removal of SCNT cattle with congenital defects caused by calf death loss. As a result of comparative studies of SCNT cattle and conventionally bred cattle, the substantial equivalences in animal health status, milk and meat productive performance have been confirmed. Both sexes of SCNT cattle surviving to adulthood were fertile and their reproductive performance, including efficiency of progeny production, was the same as that in conventionally bred cattle. The presence of substantial equivalence between their progeny and conventionally bred cattle also existed. Despite these scientific findings, the commercial use of food products derived from SCNT cattle and their progeny has not been allowed by governments for reasons including the lack of public acceptance of these products and the low efficiency of animal SCNT. To overcome this situation, communication of the low risk of SCNT technology and research to improve SCNT efficiency are required.     

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。     

An international panorama of goat selection and breeds

The preservation of the biodiversity of animal breeds is an important condition to maintain the ability of animal production to adapt to the changing conditions of breeding and production systems in the future. The decrease of the number of animal breeds has been observed both for sheep, cattle and goats in relation with the standardisation and intensification of animal production systems.Goats are mainly concerned by the situation as they have the biggest increase in livestock numbers in 20 years. A global overlook of goats worldwide is showing a contradictory situation: On one hand, small but well organised sectors have developed in a few countries for milk and cheese, meat and fibre production. On the other hand, most of the goats are mostly still used for auto consumption of milk meat and skin or fibres in village herds. The present goat genetic situation is the direct consequence of this evolution with the high specialisation of a small number of selected and well characterised breeds for milk, meat and fibres and a majority of not well defined populations and local breeds, generally without selection schemes and organisation.A global panorama of the main families and breeds is presented. A special consideration is then pointed on the necessary financial and logistic conditions to achieve successively these selection objectives. After having observed that in many cases these conditions are not present, this report concludes by some proposals to control better the possibilities of success and express with more efficiency the genetic potentiality of this interesting species.     

Productivity in different cattle production systems in Kenya

Cattle are kept as an important source of livelihood in many Kenyan farming households whilst also having cultural and social value. A review was undertaken to estimate productivity in the three main Kenyan cattle production systems: small-scale dairy and meat; small-scale dairy; and large-scale dairy and meat. Data on production parameters were collected through a systematic literature search of electronic databases for peer reviewed and grey literature. The parameters included were reproductive rates, mortality rates and yields. Prices for livestock and livestock products were estimated from markets. The data were used to estimate net output from cattle using the Livestock Productivity Efficiency Calculator (LPEC), a deterministic steady state model which measures productivity as net output per megajoule (MJ) of metabolisable energy (ME). The estimated net outputs per livestock unit year^?1 were USD 146.6, USD 215.1 and USD 84.8 in the large-scale dairy and meat, small-scale dairy and meat and small-scale dairy systems, respectively. Milk production contributed significantly to net output in all systems and was 91.8 % of total output in small-scale dairy. Cattle sales had the highest contribution to net output in large-scale dairy and meat system (45.1 %). Sensitivity analysis indicated that output was most affected by milk yield, age and weight at maturity and parturition rate. The productivity differences between the production systems call for more detailed research on the constraints to the production systems such as diseases, and to describe the benefits that farmers and society would obtain from disease control and improved management.     

Using genetic evaluations for growth and maternal gain from birth to weaning to predict energy requirements of Line 1 Hereford beef cows

The maintenance energy required to sustain the cow herd is a major cost of beef production. This work proposes modifying parameter estimates for a population-specific lactation curve with genetic evaluations for the maternal genetic effect on calf gain from birth to weaning to provide inputs for a commonly used prediction of energy requirement. Daily milk production (y) was modeled as a function of stage of lactation (T, d) using the function y = AT(B)exp(-CT) modified to incorporate effects of genetic evaluation for the maternal effect on calf gain from birth to weaning and age of dam. A 1-kg increase in predicted maternal breeding value for calf gain from birth to weaning from within-herd genetic evaluation increased the lactation curve parameter A by 10.3+/-4.6% and reduced the B parameter by 1.0+/-0.6%. Similarly, a 1-kg increase in maternal breeding value for gain from birth to weaning from national cattle evaluation increased the A parameter by 1.7+/-0.2%. Corresponding estimates of peak milk yield and time of peak lactation were derived for individual animals from their genetic evaluation. Additional inputs for predicting maintenance energy requirements were derived from genetic evaluations for birth weight and mature size. The methodology is demonstrated using genetic evaluations of sires from the Miles City Line 1 Hereford population. Further refinement and application of this methodology may facilitate characterization of beef cattle seedstock for their potential genetic contributions to profitability.     

晋南牛饲养管理配套技术推广

“晋南牛饲养管理配套技术推广”是山西省科委１９９９年度下达“山西省农村技术承包”项目，其目的是针对我区广大农户养牛饲养管理粗放、商品牛出栏率低、产肉率低、母牛繁殖成活率低、经济效益差等缺点，通过采用肉牛杂交改良，改良肉牛饲养管理、加强母牛饲养营养、犊牛培育、秸杆氨化、放牧牛冬春补饲等配套技术，达到提高养牛业科技含量，增加养牛业经济效益的目的。     

Integrating banana and ruminant production in the French West Indies

Using a mechanistic model, we compared five alternative farming systems with the purpose of transforming monoculture (MON) banana farms into mixed farming systems (MFS) with ruminants feeding banana by-products (leaves, pseudostems and nonmarketable fruits) and forage from the fallow land. The paper presents the main structure of the model (land surface changes, available biomass for animals, stocking rates, productive or reproductive indicators), and impact assessment (change in farm productivity) is discussed. Five MFS with typical local ruminant production systems were used to compare MON to the strategies using forage from fallow and/or integrating Creole cattle (CC), Creole goats (CG) or Martinik sheep (MS) into banana farming. One hectare MON shifted into an MFS allows a stocking rate of 1,184, 285, and 418 kg of live weight per hectare for CC, CG and MS, respectively. Banana by-products seem to be better valorized by the CC scenario. However, parameters such as length of the cycle, local prices for cattle, goat and sheep meat, work time and farmer's skills in ruminant management may have been taken into account by the farmer when choosing the ruminant species to rear.     

夏南牛和皮南牛及南阳牛的生长发育模型化研究*

南阳牛以体格大、役肉兼用、耐粗饲、适应性强而著称,夏南牛和“皮南牛”是以南阳牛为基础育成的肉牛品种,本文采用模型化方法对其体重生长发育及早熟性进行了研究。结果显示,夏南牛和“皮南牛”具有生长发育早熟性较好,生长强度大的特点,断奶重相对较大,12月龄体重分别相当于其36月龄体重的56.60%和62.21%。其中,“皮南牛”在周岁以前生长强度更大。     

新疆褐牛的资源状况与发展策略

新疆褐牛是中国优良的地方品种,同时也是乳肉兼用品种,对发展地方经济、农牧民增产增收起到重要的作用。本文就新疆褐牛的资源状况、存在的问题以及发展展望等方面做了详细阐述,希望能推动新疆褐牛业的快速、健康、持续发展。     

培育肉用南阳牛有关问题的商榷

作者针对传统上向役用方向进行选择的我国体大力强、肉质细致、育肥潜力较大的优良地方品种——南阳黄牛,具有后躯欠丰满、成熟晚、泌乳量低、生长较慢等缺点,利用当前南阳黄牛场规模较大,条件较好的条件,通过引血杂交改良,扩大杂种头数,加强选育,最后选出理想型杂种公母牛进行自群繁育,培育成拥有2万头数量的南阳肉牛新品种。     

Factors Affecting the Readiness and Preparation of Replacement Heifers in Tropical Breeding Environments

The future of beef cattle production in tropical regions is uncertain because of land tenure concerns, threatening the survival of extensive management programmes in these areas of the world. The need to intensify production systems will inevitably lead to changes in the management of replacement animals in existing herds. The present review underlines the main constraints, which in the past could be resolved by the sheer numbers of animals present in beef cattle operations, with replacements reliant only on finding enough heifers to substitute the adult females destined for culling. This scenario is rapidly changing as beef cattle units in tropical regions subdivide to share out the land between as many farmers as possible. Consequently, issues such as the efforts needed to manage the pregnant cow, particularly her nutritional status and its effect on the new‐born calf, the future replacement heifer growing in the presence of the dam, weaning management and procedures required before a heifer can be introduced into a breeding programme, need to be adequately and efficiently addressed by farmers in tropical regions.     

牛泌乳性状QTL的研究进展

家畜数量性状位点（QTL）的寻找与定位是目前一个重要的研究热点。在牛的泌乳性状方面，国内外研究者对产奶量（milk yield），脂肪产量（fat yield），蛋白产量（protein yield），乳脂率（fat percentage），乳蛋白率（protein percentage），产奶寿命（productive herd life）等性状均找到一些QTL。本文介绍近期有关牛泌乳性状的QTL的研究情况。