Estimation of economic weights for number of teats and sperm quality traits in pigs

Accurate predictive modelling facilitates efficient and effective trait selection in animal breeding and can decrease costs while maximizing profits when raising economically important animals. The objective of this study was to extend a previously developed bioeconomic model and computer program to calculate the marginal economic values (MEVs) and economic weights (EWs) for direct and maternal pig traits affected by new reproductive traits, namely the number of sow functional teats (NFTs) and boar sperm quality traits (SQTs) that included sperm volume, sperm concentration, motility percentage and percentage of abnormal spermatozoa. The MEV of NFTs represented the cost differences between naturally and artificially reared piglets until weaning and the cost differences between naturally and artificially reared finished animals. The MEVs of SQTs expressed the saved costs for artificial insemination, assuming a decreased price per insemination dose when improving the SQTs. The absolute and relative EWs for the newly defined complex of traits in the breeding objectives for pig breeds involved in the Czech national three-way crossing system (Czech Large White [CLW], Czech Landrace [CL] and Pietrain [PN]) were calculated using gene flow methods. The NFT trait was included only for dam breeds, and the relative EW averaged 3.6% of the total economic importance based on the genetic standard deviations of all 19 simultaneously evaluated traits in CLW and CL breeds. The relative EWs of the four SQTs comprised 2.0% of the total economic importance of the 19 traits in the CLW and CL dam breeds and 8% of the total economic importance of the 18 traits in the PN sire breed. Therefore, inclusion of the NFTs for dam breeds and SQTs for sire breeds in the breeding goal is recommended to aid in obtaining ideal outcomes with optimal economic values.     

Economic weights for sow productivity traits in nucleus pig populations

Economic values or weights measure the net economic gain per unit genetic increase of a given trait. These were derived for sow productivity traits for use as weighting factors in a dam line selection index used by purebred or nucleus dam line breeders. The profit function approach was used in order to provide flexibility to alternative production systems, market requirements or population trait levels. The approach accounted for constraints on perinatal survival rate imposed by larger birth litter sizes. The effect of accounting for these constraints was to reduce the economic value of birth litter size as the population average increased; without this, the economic weight for litter size was constant. Weights for the other traits were not affected. Economic weights were calculated for both the 100 kg finished pig and the 25 kg feeder pig market, and for a range of average birth litter sizes, with constant values for all other traits, using average market conditions, prices and costs in Canada as an example. The relative importance of litter size for the finished pig market decreased from 64% of the total breeding value when average litter size was 8 pigs to 29% when average litter size was 20 pigs, whereas that of perinatal survival increased from 17% to 42%, and that of survival to weaning increased from 7% to 18%. The relative importance of litter size for the feeder pig market also decreased from 45% to 15% as average litter size increased from 8 to 20 pigs, whereas that of piglet weaning weight increased from 22% to 41%, that of perinatal survival increased from 12% to 22% and that of survival to weaning increased from 5% to 9%. The relative importance of age at puberty and weaning to conception interval were both less than 8% of the total in both markets at all litter sizes. These results show that economic weights for litter size designed for populations with relatively small litter sizes should be reduced when the average litter size becomes large and more emphasis should be placed on other traits, particularly perinatal survival.     

Breakeven prices for recording of indicator traits to reduce the environmental impact of milk production

A breeding scheme using genomic selection and an indicator trait for environmental impact (EI) was studied to find the most effective recording strategy in terms of annual monetary genetic gain and breakeven price for the recording of indicator traits. The breakeven price shows the investment space for developing a recording system for an indicator trait. The breeding goal consisted of three traits – milk production, functional trait and environmental impact – with economic values of €83, €82 and €?83, respectively. The first scenario included only breeding goal traits and no indicator traits (NoIT). The other scenarios included all three breeding goal traits and one indicator trait (IT) for EI. The indicator traits were recorded on a large scale (stayability after first lactation and stature), medium scale (live weight and greenhouse gases (GHG) measured in the breath of the cow during milking) or small scale (residual feed intake and total enteric methane measured in a respiration chamber). In the scenario with stayability, the genetic gain in EI was over 11% higher than it was in NoIT. The breakeven price of recording stayability was €8 per record. Stayability is easy to record in the national milk recording system, and its use as an indicator trait for EI would not generate any additional recording costs. Therefore, stayability would be a good indicator trait to use to mitigate EI. The highest genetic gain in EI (23% higher compared to NoIT) was achieved when the GHG measured in the breath of the cow was used as indicator trait. The breakeven price for this indicator trait was €29 per record in the reference population. Ideally the recording of a specific indicator trait for EI would take place when: (i) the genetic correlation between the IT and EI is high; and (ii) the number of phenotypic records for the indicator trait is high enough to achieve a moderately high reliability of direct genomic values.     

Estimation of heritability of feeding behaviour traits and their correlation with production traits in Finnish Yorkshire pigs

A major proportion of the costs of pork production is related to feed. The feed conversion rate (FCR) or residual feed intake (RFI) is thus commonly included in breeding programmes. Feeding behaviour traits do not directly have economic value but, if correlated with production traits, can be used as auxiliary traits. The aim of this study was to estimate the heritability of feeding behaviour traits and their genetic correlations with production traits in the Finnish Yorkshire pig population. The data were available from 3,235 pigs. Feeding behaviour was measured as the number of visits per day (NVD), time spent in feeding per day (TPD), daily feed intake (DFI), time spent feeding per visit (TPV), feed intake per visit (FPV) and feed intake rate (FR). The test station phase was divided into five periods. Estimates of heritabilities of feeding behaviour traits varied from 0.17 to 0.47. Strong genetic correlations were obtained between behaviour traits in all periods. However, only DFI was strongly correlated with the production traits. Interestingly, a moderate positive genetic correlation was obtained between FR and backfat thickness (0.1–0.5) and between FR and average daily gain (0.3–0.4), depending on the period. Based on the results, there is no additional benefit from including feeding‐related traits other than those commonly used (FCR and RFI) in the breeding programme. However, if correlated with animal welfare, the feeding behaviour traits could be valuable in the breeding programme.     

家畜多脊椎性状研究进展

多脊椎性状是指动物脊椎数比正常个体增加的现象,是存在于家畜中的有益突变。胸腰椎数的增加可增大家畜的体长,改变相应胴体指标,从而提高其经济价值。多脊椎性状具有较高遗传力,这为多脊椎肉用家畜的选择和培育奠定了遗传基础,使多脊椎个体在家畜遗传改良中发挥优良的生产性能成为可能。因此,家畜多脊椎性状的研究,可为多脊椎肉用家畜新品种的培育奠定理论基础。目前,已在猪、羊和牛3种家畜上发现多脊椎现象。其中,猪多脊椎性状的研究已取得了较大的进展,而牛和羊多脊椎性状的研究结果则相对有限。作者就家畜中的脊椎数变异情况、多脊椎性状对家畜生产性能的影响及其候选基因/突变位点的研究3方面内容进行阐述,并简要分析了家畜多脊椎性状研究空白及可能的研究方向。     

Effects of incorporating environmental cost and risk aversion on economic values of pig breeding goal traits

Economic values (EVs) of traits, accounting for environmental impacts and risk preferences of farmers, are required to design breeding goals that contribute to both economic and environmental sustainability. The objective of this study was to assess the effects of incorporating environmental costs and the risk preferences of farmers on the EVs of pig breeding goal traits. A breeding goal consisting of both sow efficiency and production traits was defined for a typical Brazilian farrow‐to‐finish pig farm with 1,500 productive sows. A mean‐variance utility function was employed for deriving the EVs at finishing pig level assuming fixed slaughter weight. The inclusion of risk and risk aversion reduces the economic weights of sow efficiency traits (17%) while increasing the importance of production traits (7%). For a risk‐neutral producer, inclusion of environmental cost reduces the economic importance of sow efficiency traits (3%) while increasing the importance of production traits (1%). Genetic changes of breeding goal traits by their genetic standard deviations reduce emissions of greenhouse gases, and excretions of nitrogen and phosphorus per finished pig by up to 6% while increasing farm profit. The estimated EVs could be used to improve selection criteria and thereby contribute to the sustainability of pig production systems.     

中国瘦肉型猪育种目标性状经济权重的测算

为了加快我国瘦肉型猪育种的研究进展,制定出符合我国瘦肉型猪育种现状的经济权重。本研究依据中国杜长大三元杂交猪育种现状,选择了适合中国当前杜长大三元杂交体系的目标性状;以生物经济模型为基础模拟猪的生产流程,计算生产周期各阶段成本和收入;先采用差额法计算目标性状的边际效益,再通过各性状的遗传标准差校正得到各育种目标性状的经济权重。结果表明,目前中国瘦肉型猪育种的繁殖、生长和胴体品质性状主要包括窝产活仔数、母猪断配间隔、饲料转化率、达100 kg体重日龄、达100 kg体重背膘厚。在我国现有生产水平和市场条件下,上述各性状的边际效益分别为：19.52、-1.07、-286.95、-8.41、-13.20元。通过计算不同品种的经济权重,得到杜洛克的饲料转化率、达100 kg体重日龄、达100 kg体重背膘厚相对经济权重分别为：50.42%、34.50%、15.08%;长白和大白群体窝产活仔数、母猪断配间隔、饲料转化率、达100 kg体重日龄、达100 kg体重背膘厚的相对经济权重分别为：16.82%、0.22%、39.56%、31.42%、11.98%和32.77%、0.41%、33.22%、24.43%、9.17%。结果显示,目前,在中国瘦肉型猪育种过程中,饲料利用效率应作为育种的主要目标性状,对于不同品种应选择最适合的性状进行育种。     

Impact of crossing system on relative economic weights of traits in purebred pig populations

The relative economic importance of traits was calculated for various crossbreeding systems in pigs. The influence of the following three factors on the relation of standardised and discounted economic weights (SDEW) for reproduction and production traits was investigated: (i) the position of breeds in the crossing system, (ii) the use of breed-sex groups for mating in different tiers and (iii) the level of the management input parameters. The SDEW for each trait was calculated as the product of the marginal economic value, the genetic standard deviation and the number of discounted expressions. The ratio of SDEW for reproduction traits to SDEW for production traits was from 3 : 1 to 3.7 : 1 which is about twice the value of the corresponding ratio of undiscounted standardized economic weights (1.7 : 1). There were small differences in the ratio of standardized economic weights for number born alive and average daily gain (SDEWR) between males and females used for mating in the same tiers within a given crossing system (less than 1%). In each breed-sex group, there were significant differences in the SDEWR (up to 24%) dependent on the use of this group for mating in different tiers within a given crossing system or in different crossing systems. This means that clients at multiplier and commercial levels should rank the genetic merit of their breeding stock differently from that of a common breeding objective. In crossing systems with two dam breeds without reciprocal crossing, the SDEWR was higher in the breed used in granddam position than in the breed used in grandsire position (about 20% under Czech conditions). Changes in the management parameters had only a minor impact on the SDEWR.     

Simulation of genetic control of reproduction in beef cows. III. Within-herd breeding value estimation with known breeding dates

Procedures for breeding value estimation for reproductive traits with known breeding dates were developed and tested using results of a computer simulation model of genetic control of bovine reproduction. The model generated realized reproductive outputs as a function of underlying genetic variation in two independent traits: conception rate (CR), which was indicative of the ability to conceive given estrus, and PPI, the postpartum interval from calving to first estrus. Two scenarios were considered. In the first, all cows were assumed to be cycling at the start of breeding and to be bred artificially. For this scenario, breeding values for CR could be estimated from information on observed breeding and calving dates by using a categorical trait, multi-stage selection model. Breeding value estimation for PPI, however, required actual measurement of PPI because if PPI and CR are genetically independent and if all cows are cycling at the beginning of breeding, subsequent breeding and calving dates are independent of PPI. The second scenario recognized that not all females would be cycling at the start of breeding. For this scenario, the categorical trait, multi-stage selection model could still be applied for breeding value estimation for CR, but accumulation of data across years was complicated by a need to consider the lifetime reproductive pattern of the individual rather than just the sum of each year's performances. Breeding value estimates for PPI could be obtained from observed breeding and calving dates for this scenario, but required consideration of the distributional properties of PPI.     

猪重大育种价值基因及挖掘技术研究进展

随着分子生物学和动物遗传育种技术的快速发展,对于畜禽优良性状的研究已从对表型选育进入到对单个或多个重要性状关联基因的分子选育,如对猪肉质性状的相关研究,在影响猪背膘厚、肌内脂肪含量、火腿重量等方面筛选到许多关键基因。近年来,非洲猪瘟肆虐,对猪抗病的研究再次成为热点,也发现了众多关键基因,如CD163直接参与了猪呼吸与繁殖综合征病毒的侵入机制。除了疾病的影响外,繁殖性状对养猪业的发展也起着至关重要的作用。随着研究人员对各重要性状研究的不断深入,现已积累了大量重要育种价值基因的多维数据,且由此开发出了多种基因筛选技术,尤其是CRISPR-Cas9基因编辑技术的发现及其作为全基因组筛选工具的成功应用,以及在后基因组时代功能基因组筛选与多组学的联合应用等,进一步推动了遗传育种领域的发展。作者系统总结了猪肉质、抗病及繁殖性状相关的重要育种价值基因及其挖掘技术,以期为猪的遗传改良提供指导性建议和参考。     

A global strategy of using molecular genetic information to improve genetics in livestock

Traditional breeding programmes have largely contributed to disseminate the benefits of several quantitative traits in livestock. In developing countries such as Indonesia where animal population scattered throughout the country, it is difficult to invest for molecular research. On the other side, yet, it is worthy asset for breeding purposes. Based on theory and evidence, it has been proved that those scattered population evolved different genetic adaptations in response to a given natural pressure selection. A global strategy can be applied to the use of molecular genetic information for identification of economically important value. The use of genetic markers or more effective of marker-assisted selection (MAS) for desired important traits would be more valuable and useful and even more efficient in important trait selection of superior livestock. DNA marker technology would be very useful when applied for quantitative trait identification. Marker-assisted selection can be used for enhancing conventional breeding and works best for the traits with low heritability such as in reproductive traits and disease resistance. Application of conventional breeding for lower heredity traits would not be efficient because of waiting longer for generation interval, expensive in measurements, more population and more employees needed. Study of quantitative trait loci mapping is early investment to improve genetic merit. It can be performed once but can be used for exploring many genetic traits with economically important values. An effective option is biotechnology application in livestock for the development of genetic varieties such as stress tolerance, growth and carcass traits. Application of biotechnology approaches will enable improvement in productivity, reduction in costs, enrichment of milk compositions and extension of shelf life products.     

Modelling of a recording scheme for market-oriented smallholder pig producers in Northwest Vietnam

Village breeding programmes are being developed by an integrated long-term project for smallholders in Northwest Vietnam to improve pig production in different production systems. In total, 120 smallholders with 169 sows in 5 of the 9 project villages were approached in single person interviews, using a structured questionnaire. Frequency analysis of data on breeding management and ranking of smallholders' trait preferences and selection criteria used for pigs were performed with SAS 9.1, using the FREQ procedure. Survey results indicate that both improved local breeds and exotic genotypes should be incorporated in future village breeding programmes for market-oriented smallholder pig production, improving the reproductive and growth performance as well as the carcass quality. In a next step, a model reflecting the status quo at farms with market-oriented pig production was developed integrating data from farmers' survey and information from the project's current recording scheme. A deterministic approach was used to assess the profitability and genetic merit of the current recording scheme. Modelling results show that the current recording scheme is unprofitable (− 33.90 € sow^− 1). As continued success of village breeding programmes depends on the profitability of breeding measures, the long-term sustainability of the current recording scheme seems unlikely. Genetic gains are achieved in production and carcass quality traits, while a small reduction in reproduction traits can be observed. In a last step, possible effects of increased pig performances on the profitability and genetic merit of the current recording scheme were evaluated. Effects of increased pig performances on the genetic and economic success of the recording scheme are generally limited. Further model calculations are necessary for finding possibilities to improve smallholder pig breeding in a profitable way.     

中国肉用西门塔尔牛育种目标性状的选择及其经济权重的测算

为了选育中国西门塔尔牛肉用品系,本研究从中国肉用西门塔尔牛育种实践出发,确定了适应当前中国肉用西门塔尔牛的育种目标性状和选择性状。采用差额法计算出各目标性状的边际效益,并通过各目标性状表型值的遗传标准差校正边际效益,得到相应育种目标性状的经济权重。结果表明,中国肉用西门塔尔牛近期的育种目标性状主要包括生长发育性状（断奶重、育肥期日增重、18月龄体重）、胴体性状（胴体品质、屠宰率、净肉率）及繁殖性状（初产年龄、产犊间隔和留群时间）。在现有市场和生产条件下,上述育种目标性状的边际效益分别为17.93元/kg、16.2元/kg、7.17元/kg、297.99元/级、497.82元/%、594.46元/%、-3.62元/d、-26.55元/d、232.75元/y,3类性状中生长发育性状、胴体性状及繁殖性状的经济权重之比为31.49%：15.86%：52.65%,约为2：1：3,繁殖性状占总经济权重最高,其次是生长发育性状和胴体性状。综上所述,在中国肉用西门塔尔牛育种过程中,繁殖性状具有最重要的地位,需加强繁殖性状的选择力度。     

Genotype by environment interaction for lamb weaning weight in the Norwegian White Sheep breed

Abstract

Genotype by environment (G×E) interaction effects influence phenotypic expressions of a trait and may be of importance for sheep breeding. Interaction effects are more likely to be present when there are large environmental differences. Norwegian sheep usually graze mountain or forest pastures during summer. In this study, we estimate G×E interactions in Norwegian White Sheep as genetic correlation between area-specific traits (autumn lamb weight) in three ram circles located in two different counties; two in Buskerud in the south and one in Troms to the north of the country. Using data from the National Sheep Recording System, a bivariate animal model was fitted and genetic correlations for each trait were obtained. None of the correlations were significantly different from unity indicating the absence of G×E interaction effect for weaning weight. To gain further insight, studies should include a breeding-goal level aggregation of all traits thought to contribute to profitability.     

Selection of Objective Traits and Estimation of Economic Weights for Chinese Simmental Beef Cattle

In order to breed a beef line in Chinese Simmental cattle,this research defined breeding objective traits and selected traits according to real breeding condition of Chinese Simmental beef cattle.Using the balance method to calculate the marginal benefit of each objective trait and getting the corresponding economic weight of breeding objective traits through the standard value of the error corrected marginal benefit of breeding objective traits.The results showed that breeding objective traits mainly included growth traits (including weaning weight,fattening daily gain,18th month weight),carcass traits (including carcass quality,dressing percentage,pure meat percentage) as well as reproductive traits (including age at first calving,calving interval,stay group time).In the current market and production conditions,the marginal benefit of the breeding objective traits were 17.93 yuan/kg,16.2 yuan/kg,7.17 yuan/kg,297.99 yuan/grade,497.82 yuan/%,594.46 yuan/%,-3.62 yuan/d,-26.55 yuan/d and 232.75 yuan/y,respectively,and the ratio of relative economic weights of three kinds of traits was 31.49%:15.86%:52.65%,similar to 2:1:3,and reproductive traits occupied larger economic weight,was better than growth traits and carcass traits.The results indicated that reproductive traits played an important role in the process of breeding in Chinese Simmental beef cattle,and we needed to strengthen the selection of reproductive traits.     

Genetic change results from selection on an economic breeding objective in beef cattle

The objective of this study was to evaluate and quantify the genetic progress achieved in a New Zealand Angus nucleus herd through long-term selection for an economically based, multi-trait breeding objective. A 4-trait breeding objective was implemented in 1976 and selected on through 1993 with traits consisting of slaughter weight and dressing percentage of harvest progeny and cull cows, and the number of calves weaned in the lifetime of each cow. These traits were related to gross income with none related to costs of production. To overcome this, economic weights were adjusted down for increased feed requirements of faster growing (and generally larger) animals. Performance and pedigree information was recorded on 16,189 animals from 1976 through 1993 and included weaning, yearling, and mature cow weights along with the lifetime number of calves weaned by each cow. These traits were used in the phenotypic selection indexes developed to predict the defined breeding objective. Individual performance was adjusted by least squares for major environmental fixed effects and deviated from contemporaneous means. Genetic and residual (co)variances were re-estimated for each of the traits using REML techniques and used to calculate EBV for each trait. These EBV were in turn used to calculate annual genetic changes. The average annual genetic changes for weaning weight direct and maternal breeding value were 0.43 +/- 0.05 and 0.03 +/- 0.22 kg/yr, respectively. Corresponding annual genetic changes for postweaning BW gain, yearling weight, harvest weight, and mature BW were 0.29 +/- 0.03, 0.72 +/- 0.06, 1.7 +/- 0.13, and 0.13 +/- 0.09 kg, respectively. The annual change in number of calves weaned per cow lifetime was 0.006 +/- 0.001 calves/cow and the change in dressing percentage was estimated to be -0.035 +/- 0.003 %/yr. At the end of the program, 3.21 generations of selection had occurred with a mean accumulated selection differential of 3.87 SD. Change in objective traits due to selection was similar to or exceeded change predicted at the onset of the program with the exception of mature BW and dressing percentage. Genetic change in mature BW was not different from zero, whereas the predicted change was 29.3 kg. The overall genetic trend in the breeding objective exceeded that predicted at the onset of the program. Results of this study showed that selection on indexes developed to predict an economically based, multi-trait breeding objective will produce genetic change.     

野猪、松辽黑母猪及其杂交一代多性状功能基因分子遗传标记研究

本研究旨在应用"中芯一号"家猪分子育种基因芯片了解试验猪群重要经济性状功能基因遗传变异,为选留优秀育种个体提供有效信息。选择影响猪脂肪沉积、肉质、生长、抗病和被毛表型等性状功能基因有效突变位点作为分子遗传选育标记,以野猪、松辽黑母猪及其杂交一代共计106头个体作为实验动物模型,通过"中芯一号"猪分子育种芯片检测,对试验猪不同性状功能基因有效突变位点进行统计分析。结果表明,猪脂肪沉积性状功能基因（SCD和MYH4）有效突变位点在试验猪群中全部是肌内脂肪沉积有利基因型（CC、TT）;肉质性状功能基因（PHKG1、PRKAG3和RYR1）有效突变位点,除了21头猪携带有RYR1功能基因有效突变位点对肉质性状不利的等位基因T外（杂合基因型CT）,其他个体全部为肉质性状有利基因型（CC、GG、CC）;抗病性状功能基因MUC13有效突变位点的抗病有利等位基因纯合基因型（GG）所占比例高于杂合（GA）和不利等位基因纯合基因型（AA）;生长性状功能基因（HMGA1、VRTN和CCKAR）有效突变位点检测发现,猪群中没有增加体长趋势的HMGA1突变位点的TT基因型个体,仅有1个杂合体;肋骨数功能基因VRTN有效突变位点T等位基因频率高,对个体的胸椎数有增加趋势;功能基因CCKAR有效突变位点全部是有利于增加采食及日增重的C等位基因纯合基因型;被毛表型性状KIT功能基因有效突变位点在所有检测猪个体呈现出GG基因型,说明研究猪群中不存在影响白色被毛表型的基因突变位点,与试验猪群被毛表型结果一致。以上结果为猪群进一步育种规划提供了有益信息。     

Evaluating breeding objectives for sow productivity and production traits in Large White Pigs

the objective of the study was to develop and evaluate different breeding objectives for sow productivity and for production traits, using economic selection indices. Genetic parameters were generated using a repeated records model for sow productivity traits and a maternal effects model for production traits, in ASREML. Stochastic simulation models based on a hypothetical 100-sow model were performed for each line, i.e., a dam line and a terminal sire line, respectively, to derive economic values. The traits included in the study were number born alive (NBA), 21-day litter size (D21LS), 21-day litter weight (D21LWT), average daily gain (ADG), feed conversion ratio (FCR), age at slaughter (AGES), dressing percentage (DRESS), lean content (LEAN) and backfat thickness (BFAT). The economic values for LEAN and BFAT were derived using the partial differentiation of the profit function, while those for the other traits were derived using the partial budget approach. An economic value of a trait was the change in profit per unit genetic change in that trait. Breeding objectives were developed with a corresponding selection index, for improvement of that objective. Three combinations of breeding objectives and selection indices were developed for sow productivity traits, while there were 15 combinations for production traits. Responses to selection and economic return were computed for each combination to determine the most appropriate combination for the improvement of the breeding objective traits. The most appropriate index to improve sow productivity consisted of NBA and D21LWT. For production traits, the combination that consisted of a selection index with AGES, DRESS and BFAT, and the breeding objective ADG, DRESS, FCR and LEAN, was considered the most appropriate. Age at slaughter and BFAT were, respectively, included as indicator traits for ADG and LEAN. The recommended breeding objectives were sensitive to changes in economic values, indicating that economic values for breeding goal traits should be updated periodically to ensure proper weighting of traits, hence maximization of economic return.     

Economic weights of production and functional traits for Holstein‐Friesian cattle in Hungary

A bio‐economic model was used to estimate economic values of 15 milk production, functional, growth and carcass traits for Hungarian Holstein‐Friesian cattle. The calculations were carried out for the situation in Hungary from 2000 to 2007, assuming no production quotas. The marginal economic values were defined as partial derivatives of the profit function with respect to each trait in a production system with dairy cow herds and with sales of surplus male calves. The economic weights for maternal and direct components of traits were calculated multiplying the marginal economic values by the number of discounted expression summed over a 25‐year investment period for 2‐year‐old bulls (candidates for selection). The standardized economic weight (economic weight × genetic standard deviation) of the trait or trait component expressed as percentage of the sum of the standardized economic weights for all traits and trait components represented the relative economic importance of this trait or trait component. The highest relative economic importance was obtained for milk yield (25%), followed by productive lifetime of cows (23%), protein yield and the direct component of a cow’s total conception rate (9% each), the maternal effect of the total conception rate of cows and the somatic cell score (approximately 7% each), fat yield (5%) and mature weight of cows and daily gain in rearing of calves (approximately 4% each). Other functional traits (clinical mastitis incidence, calving difficulty score, total conception rate of heifers and calf mortality) reached a relative economic importance between 0.5% and 2%. Birth weight and dressing percentage were least important (<0.5%). Based on these results, the inclusion of productive lifetime and cow fertility in the breeding programme for Holstein‐Friesian cattle in Hungary is advisable.     

生猪养殖中育肥阶段饲养管理技术分析

近年人们对于猪肉的需求量越来越高,猪肉需求量的增加有效的推动我国生猪养殖业的发展,使生猪养殖朝规模化、集体化养殖发展,在一定程度上满足人们生活上对猪肉的需求。在生猪养殖中,生长育肥是生猪生长的重要阶段,其生长决定生猪的生长品质和养殖户的经济效益。该文通过对育肥猪的生长规律、育肥方式、饲养管理和生活环境卫生等方面进行论述,并提出育肥猪科学饲养管理中需要注意的问题和管理措施,确保生猪在育肥阶段的健康生长和养殖员的经济效益。