第四章家禽数量性状的遗传课件.ppt

1、 肉用性状（肉用性状（meat trait）的遗传）的遗传 蛋用性状（蛋用性状（egg trait）的遗传）的遗传 繁殖力和生活力的遗传繁殖力和生活力的遗传 饲料报酬饲料报酬(feed remuneration)体型大小（体型大小（body size）或体重（）或体重（body weight）1.出壳体重（出壳体重（day-old weight）2.生长期体重（生长期体重（grower weight）：）：6-7周周龄体重龄体重h2=0.42-0.46 3.成年体重（成年体重（adult weight）h2=0.55-0.65 生长速度（生长速度（growing rate）1.累积生长（累积生

2、长（accumulate growing）2.绝对生长（绝对生长（absolute growing）3.相对生长（相对生长（relative growing）早期生长速度早期生长速度h2=0.4-0.5 Genetic parameters of growth curve in chickens(S.Genetic parameters of growth curve in chickens(S.Mignon-Grasteau and C.Beaumont,2019,7Mignon-Grasteau and C.Beaumont,2019,7thth WCGALP,11-3)WCGALP,11

3、-3)Gompertz function of growth curve:maximum.is rategrowth at which ,inflectionat Age|:L/K|ln 1/K TI rate.maturation the:Krategrowth specific initial the:L age),infinitean at (i.e.,t body weigh asymptotic the:t,ageat t body weigh:)/(ABWAeBWteKLtKt By using data of 464 chickens from a slow growing me

4、at-type line,which were weighed every two weeks from 4 to 16 weeks,the Gompertz curve fitted well the data(R2=0.99),the greatest difference being an overestimation of body weight at 10 weeks(3.6%in males and 2.8%in females).Conclusion:This study confirmed that males and females chickens can be disti

5、nguished by their growth curve parameters,females being more precocious than males.Genetic parameters of the Gompertz function parameters showed moderate heritabilities,making it possible to select directly on the form of the growth curve.屠宰率（屠宰率（dressed percentage）h2=0.2-0.6%100%100%;100%100全净膛重上、下

6、腿肌重腿肌率；全净膛重胸肌重胸肌率活重半净膛重半净膛率；活重全净膛重全净膛率 Genetic and phenotypic parameters of growth and Genetic and phenotypic parameters of growth and carcass traits of a male line of broilers raised carcass traits of a male line of broilers raised in tropical conditions(C.Argento1 et al 2019,in tropical conditions

7、(C.Argento1 et al 2019,7 7thth WCGALP 4-34)WCGALP 4-34)The dataset information came from a male selection line of broilers owned by Agroceres-Ross Melhoramento Gentico de Aves Ltda.and raised in tropical conditions in farm located close to 22S and 48W,at altitude around 700 m above sea level.Growth

8、data came from 27,231 male and female birds submitted to selection and dataset had information on 5 generations of pedigree;Carcass data came from 9,463 full sibs of broilers from selection,that were processed at the experimental slaughterhouse.Those animals were slaughtered around 42 days of age,fr

9、om 2019 to 2019.Traits measured:W35:weight at 35 days of age,us1:ultrasound measurements on breast muscle depth(measured next to middle line);us2:ultrasound measurements on breast muscle depth(measured transversally);FC:feed conversion;LWS:live weight at slaughter;HCW:hot carcass weight;Breast:debon

10、ed and skinned chilled breast weight;Legs:chilled whole leg weight.Software:SAS,MTDFREMLConclusions:The animal model REML method seemed to be effective to estimate genetic parameters even in data of selected poultry.The growth and carcass traits of the selected male line analyzed can be used as sele

11、ction criteria,since no important genetic antagonism was observed.Economic studies should be applied to the traits analyzed,to identify which combination of them would maximize profit.As an indicator of carcass merit at slaughter(42 days of age),live weight seemed to be a good and easy to measure se

12、lection criterion,that can be widely used,as it has good genetic correlation with the other traits and medium heritability.肉鸡部分性状的遗传力肉鸡部分性状的遗传力 肉鸡部分性状的遗传和表型相关肉鸡部分性状的遗传和表型相关 产蛋量（产蛋量（egg production）入舍蛋鸡产蛋量（入舍蛋鸡产蛋量（egg production H.H-hen-housed）：以开产时入舍母鸡数为基数（包）：以开产时入舍母鸡数为基数（包括开产后死亡、淘汰母禽在内），在一定利括开产后死亡、淘

13、汰母禽在内），在一定利用期内的产蛋量。入舍母鸡用期内的产蛋量。入舍母鸡72周产蛋量周产蛋量h2=0.05-0.1饲养只日产蛋量（饲养只日产蛋量（egg production H.D-hen-day）：根据每天平均饲养母禽数计算在一）：根据每天平均饲养母禽数计算在一定时间内的平均产蛋量。饲养只日定时间内的平均产蛋量。饲养只日72周产蛋周产蛋量量h2=0.23-0.27。影响产蛋量的因素：影响产蛋量的因素：1、性成熟期性成熟期(sex maturity)：又称开产日龄：又称开产日龄(age at first egg)，指母禽产第一个蛋的日，指母禽产第一个蛋的日龄。有时用早熟性（龄。有时用早熟性（e

14、arliness）来描述性）来描述性成熟的早晚。成熟的早晚。度量方法：度量方法：个体，见第一个蛋的日龄；群体，个体，见第一个蛋的日龄；群体，蛋禽为达蛋禽为达50%产蛋率的日龄，肉用禽为达产蛋率的日龄，肉用禽为达5%产蛋率的日龄。性成熟期的产蛋率的日龄。性成熟期的h2=0.3 2、产蛋强度（产蛋强度（laying intensity）：指某一）：指某一时间内母禽的产蛋率（时间内母禽的产蛋率（laying rate），可），可用一定时间内该禽群的产蛋百分率表示。用一定时间内该禽群的产蛋百分率表示。h2=0.1 3、产蛋持久性（产蛋持久性（laying persistency）：一）：一般以生物学年

15、的长度表示，即从开产开般以生物学年的长度表示，即从开产开始，经产蛋高峰期、产蛋下降期到停产始，经产蛋高峰期、产蛋下降期到停产换羽为止所用的时间。换羽为止所用的时间。4、就巢性（就巢性（broodiness）：即抱性，为质）：即抱性，为质量性状。量性状。5、休止性（休止性（pause）：又称冬休性）：又称冬休性（winter pause）。）。产蛋持久性产蛋持久性产蛋强度产蛋强度休止性休止性就巢性就巢性性性成熟期。成熟期。蛋重（蛋重（egg weight or egg size）测量方法：国外一般测量方法：国外一般32-36周龄中连续测定周龄中连续测定3天；我国学者建议天；我国学者建议295-3

16、00天内取天内取5天平天平均蛋重。均蛋重。h2=0.2-0.7。蛋品质（蛋品质（egg quality）1.蛋壳品质（蛋壳品质（shell quality）蛋壳形状（蛋壳形状（shell shape）：用蛋形指数）：用蛋形指数（egg index）衡量，即纵径）衡量，即纵径/横径或横横径或横径径/纵经。纵经。h2=0.25-0.5 蛋壳颜色（蛋壳颜色（shell color）h2=0.3-0.9 1.蛋壳品质（蛋壳品质（shell quality）蛋壳结构（蛋壳结构（shell texture）：用三个指标，即蛋）：用三个指标，即蛋壳强度壳强度(shell strength)、蛋壳厚度、蛋壳厚

17、度(shell thickness)和蛋壳平滑性和蛋壳平滑性(shell smoothness)衡量。衡量。蛋壳强度用强度测定仪测定，分四级，正常应蛋壳强度用强度测定仪测定，分四级，正常应在在2-3级之间。级之间。蛋壳厚度可用厚度测定仪或千分尺测量，正常蛋壳厚度可用厚度测定仪或千分尺测量，正常在在244-373nm间，间，h2=0.3；也可用蛋比重；也可用蛋比重（specific gravity of eggs or egg density）间接测）间接测量，正常比重在量，正常比重在1.070-1.080间，间，h2=0.3-0.6。2、蛋白品质（蛋白品质（quality of egg whi

18、te）可用浓蛋白高度或转换成哈夫单位可用浓蛋白高度或转换成哈夫单位（Haugh unit）表示。）表示。HU=100 lg(H-1.7W0.37+7.57)浓蛋白高度浓蛋白高度h2=0.15-0.55；哈夫单位；哈夫单位h2=0.1-0.7 3、蛋黄品质（、蛋黄品质（yolk quality）：）：用两个指标度量，即蛋黄颜色和蛋黄占全蛋用两个指标度量，即蛋黄颜色和蛋黄占全蛋的比例。的比例。蛋黄颜色用罗氏比色扇测定，共分蛋黄颜色用罗氏比色扇测定，共分15级（由级（由浅黄到深黄），正常应为浅黄到深黄），正常应为12级以上。级以上。h2=0.15 正常蛋蛋黄约占全蛋正常蛋蛋黄约占全蛋30-35%（壳

19、，（壳，10-12%；蛋白，蛋白，55-60%）h2=0.1-0.4 4、血斑或肉斑（血斑或肉斑（blood spots or meat spots）种蛋容许率种蛋容许率2%，h2=0.1-0.5 蛋鸡部分性状的遗传力蛋鸡部分性状的遗传力 Estimation of genetic parameters for clutch traits in laying hens(Y.Akbas et al.,2019,7th WCGALP 04-15)Genetic Stock.Genetic Stock.egg production data of a commercial sire line at

20、6th generation.Data.The data collection period was from the 22nd to 40th weeks of age.Hens were artificially inseminated.In total 1980 animals were used from 43 sires and 8 dams per sire.Traits recorded:EN,egg numbers to 40 weeks of age for each individual.CN,clutch number.CS,average clutch size.Clu

21、tch size consists of number of days with consecutively laid eggs.At least one-day-break of oviposition was taken as the end of a clutch.DELAY,mean delay of pause days between clutches.ASM,Age at sexual maturity.BWSM,body weight at sexual maturity ageStatistical Analyses.Statistical Analyses.Model:Yi

22、jkl is any trait considered in this study,is the overall mean,fi is the fixed effect of the ith tier,sj and dk(j)are random effects of the sire and dam within sires,is the regression coefficient,x is age at sexual maturity as a covariate,eijk is the residual effect.Variance components for the traits

23、 were estimated by Restricted Maximum Likelihood(REML).ijkjkjiijklexdsfY)(Results:Higher heritability estimates from dam component as compared to estimates from sire component suggest that some maternal and non-additive effects are significant for the traits.CS,EN and CN are highly correlated traits

24、 with each other.CS has genetic correlations of-0.98,0.82 and 0.58 with CN,EN and DELAY,respectively.CN is negatively correlated with other traits considered.High heritability of CN and CS indicate that these traits may be used in the selection index of laying hens because those traits are also high

25、ly correlated with EN.繁殖力（繁殖力（reproductive capacity）家家禽繁殖后代的能力。禽繁殖后代的能力。1、受精率（受精率（fertility percentage）h2=0.05%100入孵蛋数无精蛋数入孵蛋数受精率 孵化率（孵化率（hatchability）h2=0.1-0.15%100%100入孵蛋数出雏数入孵蛋孵化率；受精蛋数出雏数受精蛋孵化力 生活力生活力(viability)在一定外界环境条在一定外界环境条件下的生存能力。件下的生存能力。1、育雏率（育雏率（brooded percentage）h2=0.05%10064入舍出壳禽数周）存活禽

26、数周（或育雏率2、存活率（、存活率（survival）：）：h2=0.05-0.1%100%100%100入舍蛋禽或种禽数禽数产蛋期结束时蛋禽或种率蛋禽或种禽产蛋期成活入舍雏禽数入舍蛋禽或种禽数蛋禽或种禽育成率；入舍雏禽数上市肉禽数肉用仔禽育成率 饲料消耗比（饲料消耗比（feed consumption ratio）h2=0.2-0.6 饲料转化效率（饲料转化效率（feed utilization efficiency）：）：饲料营养物被家禽转化用于生产产品的百饲料营养物被家禽转化用于生产产品的百分率。分率。Genetic evaluation of feed efficiency trait

27、s in a white leghorn population(R.C.Hazary,R.C.Hazary,et al.,2019,7th WCGALP,10-18)Population and selection method.Population and selection method.Two White Leghorn populations viz.IWK and Control maintained as closed flock at Experimental Farm,Project Directorate on Poultry,Hyderabad,India was util

28、ized in the present study.The IWK line was previously selected for increased egg production up to 64 weeks of age using a family index.The Control line was maintained as a random bred pedigreed population.Both lines were reproduced simultaneously and were reared under identical conditions of feeding

29、 and management Traits measured.Traits measured.The individual traits measured included body weight(g)measured at four weekly interval starting from 20 weeks of age;average egg weight(g)at 24,28,32,36 and 40 weeks of age;egg production upto 20,21-24,25-28,29-32,33-36,37-40 and upto 40 weeks of age;f

30、eed consumption(g)from 21-24,25-28,29-32,33-36,37-40 and 21-40 weeks of age and age at sexual maturity(days).Utilizing the above information feed consumed per day(g),feed consumed per dozen egg(g)and feed consumed per kilogram of egg mass(g)were derived in the entire test periods as well as on over

31、all period.Residual feed consumption was only estimated in 21-40 weeks period as difference between expected feed consumption and actual feed consumption.CONCLUSION The results clearly show that the line selected for increased egg production is more efficient in utilization of feed as compared to co

32、ntrol.Residual feed consumption is a lowly heritable trait in this line suggesting that it cannot be utilized as a selection criterion to enhance efficiency of egg production.It will be more appropriate to select on the basis of feed consumed per kilogram egg mass production that will not only take

33、care of egg production because of its favorable association with egg production but also for egg weight since it is one of the component traits.Genetic correlations of part period egg production with feed efficiency traits in the selected line were in general negative indicating that any attempt to

34、improve feed efficiency would result in improvement in egg production efficiency.剩余饲料消耗（剩余饲料消耗（residual feed consumption）：）：实际耗料量与据总产蛋量、体重和体增重计实际耗料量与据总产蛋量、体重和体增重计算出的理论耗料量之差。算出的理论耗料量之差。h2=0.42-0.62 例：据例：据NRC标准，标准，ME11.7MJ/kg的日粮，理的日粮，理论耗料量为：论耗料量为：E(FC)=46.5BW0.75+0.7EM+1.97BWGRFC=FI-E(FC)Residual food

35、 consumption as a tool to unravel Residual food consumption as a tool to unravel genetic components of food intake(M.Tixier-genetic components of food intake(M.Tixier-Boichard et al.,2019,7Boichard et al.,2019,7thth WCGALP,10-06)WCGALP,10-06)The concept of residual food consumption(RFC)was first pro

36、posed by Byerly(1941)as an approach to limit food costs in the laying hen.The possibility to select on the fraction of total food intake which is not explained by maintenance requirements and production was,indeed,an appealing way to modify food efficiency without any change in production.This was f

37、irst investigated in poultry,for the laying hen rather than for the broiler,and,later,in mammals.Extensive data have been obtained since 30 years on responses to selection on RFC in the laying hen,including metabolic studies,and,more recently,QTL detection.Prediction equationPrediction equation.The

38、classical prediction equation is a linear multiple regression of observed food intake(FI)on two types of components(1)body weight(BW)or metabolic body weight,corresponding to maintenance requirement,(2)body weight gain(BWG)which may be partitioned in protein gain and fat gain,and/or exported product

39、 such as egg output,corresponding to production needs.An intercept is generally included.RFC=FI-E(FC)E(FC)=a+b1 W G+b2 EM+b3 BW 0.75 E(FC)=Expected feed consumption.(gm/d)WG=Weight gain(gm/d)EM=Egg mass production(gm/d)BW 0.75=Metabolic body weight(g)b1,b2,b3=Multiple regression coefficient a=Consta

40、nt.Fixed effects may be added in addition to the covariables,in order to take into account effects of season,litter,or sex.Metabolic body weight is obtained as a power of body weight,the most frequently used value being 0.75.In the laying hen,the power value may vary in the range of 0.5 to 1 without

41、 affecting the efficiency of the prediction,and body weight has been shown to be an important source of variation in food intake.In the growing pig,however,performance recording is often done at a fixed body weight,and in that case,metabolic body weight does not contribute significantly to variation

42、 in food intake,but backfat thickness,and/or loin eye area have been considered as additional predictors of FI.Another type of predictor to be added could be heat production.Indeed,from the p o i n t o f v i e w o f b i o e n e r g e t i c s,metabolizable energy is a function of(1)heat production,(2

43、)energy retained as protein and(3)energy retained as fat.Thus,heat production is an obvious component of food efficiency.When heat production was added in the prediction equation of food intake in the laying hen,the residual variation was significantly decreased,and this decrease depended on the amb

44、ient temperature and on the feather cover of hens,which is also an important parameter for heat dissipation.Efficiency of the prediction equationEfficiency of the prediction equation.The residual variation in food intake which is not explained by variation in body weight and production level may rep

45、resent from 10%to 50%or more of the total variation,according to species,breed,sex,age,and environment.Regression coefficients on the different predictors will vary according to the same factors.Patterns of energy exchange during growth may be compared between species,using metabolic weight as a ref

46、erence,for instance,maximal energetic efficiency was shown to be reached at 20%of mature body size for mammals,whereas this maximal value was sustained to a higher degree of maturity for broilers chickens or quails.This may have implications regarding the most suitable period to measure RFC during g

47、rowth,according to species.Within all species,RFC depends on the breed,for example:Island-Red(RIR)layers and White Leghorn(WL)layers showed different regression coefficients,explained by different maintenance requirements,RIR showed higher body weight,%body fat,and%yolk in the egg,resulting in a hig

48、her energy content in the egg mass.Differences were also observed within breed between selected lines,for instance:In pigs,the Landrace breed was found to have a higher RFC as compared to Yorkshire and Duroc breeds or to Large White breed.Crossbreeding effects on RFC are not well documented;one stud

49、y on laying hens,obtained from crossing high and low RFC lines,showed no reciprocal effect and a negative heterosis,moderate but significant(-3.6%),on RFC.The effect of sex has not been studied to the same extent across species.1.In pigs,data are generally obtained on boars only.2.In cattle,both sex

50、es have been measured but data have generally been pooled to estimate genetic parameters.3.In the laying hen,selection has generally been done on female RFC records,but,in adult male chickens of a commercial white-egg laying strain,the regression on BW and BWG only,explained only 53%of total variati