The structure of Breeding programs in animal breeding ساختار برنامھ ھای اصلاحی در اصلاح دام

Transcription

1 The structure of Breeding programs in animal breeding ساختار برنامھ ھای اصلاحی در اصلاح دام ١

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3 نقش اصلاح دام در صنعت دامپروری پیشرفت ھا چالش ھا ٣

4 Genetic trends in a number of fertility related traits in dairy cattle in the UK expressed as the predicted transmitting abilities (PTA) per sire year of birth (YOB) Source: Wall et al., 2003

5 چند سوال: در حال حاضر در چھ وضعیتی قرار داریم آیا لازم است در اھداف اصلاحی خویش تجدید... نماي یم نظر چھ مراحلی را باید برای طراحی یک برنامھ جامع اصلاحی طی نماي یم در این طراحی چھ فاکتورھایی باید ھمواره مد نظر قرار دھیم از چھ پارامترھایی باید برای ارزیابی برنامھ استفاده نماي یم ٥

6 Where are we today? Changes that occurred in the field of animal breeding have always been connected to changes in society. One big difference in the developed world today compared to 30 years ago is that people are relatively rich and/or food has become relatively cheap.

7 Based on data FAO: On average people in European countries spend around 12% of their income on food People in In some East African countries even> 50% In Russia :31%, In India 27%, In Iran 23% In USA 7%

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9 Cheap food means that you can get more for your money In the western world there is : An increasing concern of people for how their food was produced. Healthy and natural and produced locally. Produced welfare friendly. In poorer areas of the world: The main worry is about having enough food with sufficient quality

10 Breeding program (BP) It is a system in which: 1. Information on performance of potential animals is gathered and used to estimate BV 2. Superior animals are selected and used to breed next generation. ١٠

11 Summary of structure of BP 1. Steps to design a BP 2. Factors determining the structure of BPs 3. The general structure of BPs in some livestock species 4. Parameters to evaluate BPs ١١

12 Designing a breeding program طراحی یک برنامھ جامع اصلاحی با یکسری اھداف خاص شامل چندین مرحلھ مرتبط با یکدیگر است. ھریس و ھمکاران در سال ١٩٨۴ یک پروسھ ١+٨ مرحلھ ای را برای انجام انتخاب تصمیم گیری و سایر اطلاعات مرتبط با توسعھ یک برنامھ اصلاحی جامع پیشنھاد داده اند ١٢

13 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system (breeding goal) 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ١٣

14 Harris et al (1984) stressed, that ideally the step outlined should be carried out sequentially starting 1 and continuing till 8. why? Choice, decisions and information from earlier steps influence and limit options for later steps A final step (step 9) Compare alternative combined programs ١٤

15 Step 9: Compare alternative combined programs For current scheme and alternative schemes as well The consequence of steps 1 to 8 can be evaluated Finally a BP will be chosen ١٥

16 Choosing a breeding Program 1. The predicted rate of genetic gain 2. The expected rate of inbreeding 3. Costs of running the program ١٦

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18 چھ عواملی تعیین کننده ساختار برنامھ ھای اصلاحی است برای اینکھ ما قادر باشیم در خصوص ساختار برنامھ ھای اصلاحی قضاوت و بحث کنیم باید بدانیم: چھ عواملی بر فرایند انتخاب و نیز تصمیم گیریھا در برنامھ ھای اصلاحی موثر و تعیین کننده اند مثال: متوسط فاصلھ نسل درطیور فاصلھ نسل یک سال در اصلاح نژاد طیورکوتاه بھ نظر می رسد نظر بھ اینکھ یک مرغ اولین تخمش را در سنی حدود گذارد این فاصلھ نسل نسبتا طولانی بھ نظر می رسد. ٢٠-١٨ ١٨ این مثال تاکید بر تاثیر فاکتوری نظیر ظرفیت تولید مثلی است.. ھفتگی می

19 Which factors are determining decision-making in designing breeding programs? 1. Reproduction capacity 2. Social infra-structure 3. Optimization aimed for 4. Traits in aggregate genotype 5. Genetic parameters ١٩

20 1- Reproduction capacity A very important factor in determining the structure of BP Information of RC should be summarized in step? ٢٠

21 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ٢١

22 1- Reproduction capacity (RC) Information of RC should be summarized in step 1 which is describe the production system(s) Taking the perspective of a given number of females and males in the population RC of females determines How many offspring can be produced in the population RC of males determines Number of males that are needed. ٢٢

23 1-Reproduction capacity RC has a direct effect on the choices in steps 5, 7 and 8 ٢٣

24 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ٢٤

25 Comparison RC in Dairy cattle and sheep The average record is over first inseminations per bull in one year. A few bulls are needed Those bulls are shred by many dairy farmers. In sheep natural mating One ram is needed for every ewes in a single mating season. Each farm has it s own ram ٢٥

26 The striking difference between Dairy bulls and rams Reproduction technology One bull is able to have many offspring by AI techniques ET and MOET, cloning and IVF are techniques that increase the natural reproduction capacity of females ٢٦

27 Reproduction capacity Differences in Reproduction capacity between Breeds within species It largely influence the choice of breeds (step 3) ٢٧

28 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ٢٨

29 Reproduction capacity influences How many and which animals can be used for BV estimation (step 5) Mating strategy (step7) System of dissemination of genetic superiority (step 8) ٢٩

30 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ٣٠

31 factors that determining decision-making in designing breeding programs 1. Reproduction capacity 2. Social (infra)structure 3. Optimization aimed for 4. Traits in aggregate genotype 5. Genetic parameters ٣١

32 2- Social (infra)structure It is very broad term and it s information should be summarized in step 1 In this part different aspects are considered: A. Average of farm size and distribution of farm location B. Degree of (automated) information networks C. Structure of market D. State of technology ٣٢

33 Average of farm size and distribution of farm location Large farms offer better opportunities for large-scale field testing of young unproven male (step 5) Located far or closely together which largely influences the use of superior animals (step 7 & 8) When farms are close together Transporting males on a couple of farms Use of fresh semen These choices influence on: Reproduction capacity The way information can be gathered (step 5 and 6) ٣٣

34 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ٣٤

35 Degree of (automated) information networks Information networks with regards to animal identification, pedigree, and performance recording, use of integrated uniform recording systems, etc. 1. What breeder can be done when good information network do not exist? 2. One may focus on a few farm that have enough information (amount of on information and accuracy is important) 3. Step 5 ٣٥

36 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ٣٦

37 Structure of market In poultry production certain segments of the production chain are integrated (from chicken to shop) It is possible to meet specific requirements with respect to product quality (health status) More information on breeding animals provided. A unique animal identification system is used. ٣٧

38 Milk pricing in the US 1. Fluid or beverage milk 2. Soft products (yoghurt, cottage cheese, ice cream, etc) 3. Hard cheeses 4. Butter and milk powder non-fat dry milk (NFDM). ٣٨

39 Milk Price Calculator Fat 3.80 % Protein 3.16 % Other solids 5.73 % SCC cells Current gross milk price $/cwt 1 cwt=50.8 kg Fat Protein Other solids SCC adjustment rate $/lb $/lb $/lb $/cwt ٣٩

40 State of technology Reproduction techniques Recording techniques Molecular biology techniques It influences the choice of evaluation system (step 5) ٤٠

41 State of technology Example : Different option for evaluation of carcass composition A traits which can not be measured directly on selection candidates Slaughtering sibs of selection candidates Using ultrasonic measurements of body composition on living animals ٤١

42 State of technology Example : Measuring individual Feed Intake (FI) By using electronic feeding devices it is possible to measure FI under group housing condition Otherwise animals needed to be housed individually ٤٢

43 Transition Period and it s Problems important physiological, metabolic and nutritional changes occurring in this time frame Feed intake in transition period Measuring of feeding behaviour ٤٣

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45 Controlling and Recording Feed Intake ٤٥

46 ٤٦

47 Molecular biology techniques Genetic markers It offer possibility to observe genetic polymorphism at DNA level without interference of environmental effects In all livestock species, molecular techniques applications are in two filed 1. Mapping the genome, including location and quantification of QTLs 2. Determining genetic variation within and between breeds ٤٧

48 Effect of genetic markers on structure of BP Largely increase the accuracy of selection Including an additional selection stage Allowing observations not age or sex dependent. ٤٨

49 factors that determining decision-making in designing breeding programs 1. Reproduction capacity 2. Social (infra)structure 3. Optimization aimed for 4. Traits in aggregate genotype 5. Genetic parameters ٤٩

50 Different goals in a breeding program Maximization of genetic gain In short term In long term Genetic gain In one single trait In a combination of traits Maintaining genetic variance in a population Avoiding inbreeding ٥٠

51 The average US inbreeding and milk production trends since kg 6000 kg ٥١

52 As presented by Mr. Mahnani for each 1% inbreeding increase Lifetime NM$: - 24 Age at first calving (day): Productive Life (day) -13 Lifetime milk production (lbs) -790 Lifetime protein production (lbs) : -25 First calving interval (month): ٥٢

53 Optimization Of Breeding Schemes inbreeding vs genetic gain Under the infinitesimal model Inbreeding reduces genetic gain Directly Indirectly ٥٣

54 Optimization Of Breeding Schemes inbreeding vs genetic gain Direct method Under the infinitesimal model inbreeding reduces genetic variation, which in turn reduces genetic gain. Indirect method When inbreeding depression is present, fitness of the population may reduce to an extent where it affects the selection differentials Indirectly inbreeding may also reduce genetic gain. ٥٤

55 Unfavorable relationship of inbreeding vs genetic gain Maximizing short-term response By selecting fewer parents It reduces long-term response and involves substantial risk ٥٥

56 Balance between Short-term and long-term response A restriction on the rate of inbreeding is required The objective in optimized breeding strategies Maximizing genetic gain Restricting inbreeding ٥٦

57 Acceptable levels of inbreeding The inbreeding coefficient in some of the leading Holstein countries varies between 4% and 6% The maximum acceptable level of inbreeding In some countries 5% In some countries 6.25% are considered as ٥٧

58 Two points related to inbreeding 1. Managing the increase of inbreeding per year or generation This is of more importance than managing the absolute level of inbreeding 2. Genomic selection It might help to manage the increase of inbreeding ٥٨

59 Managing Inbreeding SMS & WMS systems presented by Mr. Mahnani Managing Inbreeding instead of avoiding inbreeding ٥٩

60 Manage inbreeding (rather than avoiding inbreeding) to maximize profit Mating scenario to show inbreeding vs. potential profit ٦٠

61 Two points related to inbreeding 1. Managing the increase of inbreeding per year or generation This is of more importance than managing the absolute level of inbreeding 2. Genomic selection It might help to manage the increase of inbreeding ٦١

62 Genomic Selection or Whole Genome Selection Study of differences between individual animals in the bovine genome sequence (SNPs) It can be used to predict economically important traits, such as milk production, milk composition, health, fertility, or longevity. The genetic information for a given calf, heifer, cow, or bull is compared with that of a reference population of older animals of the same breed. More than 650,000 (recently 1000,000) dairy bulls, cows, heifers, and calves have genomic data and genomic predictions are available for Holstein, Jersey, and Brown Swiss cattle. ٦٢

63 The current cost of genomic testing (2013) 1. Low-density SNP chip: 9K or 12K $45 per animal 2. Medium-density SNP chip: 54K 3. High-density SNP chip: 648K or 777K Roughly 60,000 SNPs are used in routine genomic evaluations For animals that have been genotyped with low-density chips the remaining SNPs are imputed with 90 to 99% accuracy based on the medium- and high-density genotypes of reference animals of the same breed (Boichard et al., 2012; VanRaden et al., 2013). ٦٣

64 Holstein Association USA Genomic Testing Services Updated March 1, 2016 U.S. Customers Regular Enlight Holstein COMPLETE CLARIFIDE Low-Density SNP Test $46 $42.50 $43.70 CLARIFIDE Plus Low-Density SNP Test + Dairy Wellness Traits* n/a $50 n/a CLARIFIDE Ultra High-Density SNP Test $125 $86 $ CLARIFIDE Ultra Plus High-Density SNP Test + Dairy Wellness Traits* n/a $86 n/a Wellness Trait Upgrade for Previously CLARIFIDE-Tested Animals n/a $10 n/a Wellness Trait Upgrade for Previously Genomic Tested (Non-CLARIFIDE) Animals **Requires new DNA sample to be submitted to lab n/a $38 n/a ٦٤

65 Holstein Association USA Genomic Testing Services Updated March 1, 2016 International Customers Price Geneseek Genomic Profiler Bovine 30K (GGP-LD) $58* Geneseek Genomic Profiler Ultra High-Density Bovine 150K (GGP-HD) $135* ٦٥

66 Some benefits of genomic information In compare to the pedigree-based inbreeding coefficients Genomic data can provide more precise measures of inbreeding Genome based mating programs can accommodate both additive and dominance effects Because virtually every AI sire in the major dairy breeds has been genotyped, dairy farmers who invest in genotyping their cows, heifers, and calves can readily utilize genome-based mate selection programs They can consider average heterozygosity, dominance effects, and lethal defects ٦٦

67 Genomic Selection of Males In USA, dairy farmers have access to semen from hundreds of young genome-tested Holstein, Jersey, and Brown Swiss bulls that have no progeny of their own. The number of young AI bulls currently being marketed based on GPTA values exceeds the number of progenytested bulls being marketed Several large breeding companies now derive more than 50% of their sales from young genome-tested bulls. ٦٧

68 Genomic Selection of Males Farmers that use young genome-tested bulls to produce their replacement heifers They can reduce the generation interval (GI) for the sires to produce daughters selection pathway From 72 months with traditional progeny tested bulls to about 30 months Furthermore, these young genome-tested bulls are often used to produce the next generation of AI bulls, and the impact on generation interval is dramatic From 63 months with traditional progeny tested bulls to about 21 months look at to the next figure ٦٨

69 Timeline of a traditional AI breeding program based on progeny testing (from Schefers and Weigel, 2012). Prove at 54 months ٦٩

70 In a traditional breeding program based on progeny testing Approximately 54 months are required for rearing a bull, collecting and distributing his semen, rearing his offspring, recording his offspring s phenotypes, and predicting his breeding value using pedigree-based BLUP. At this point, the bull can be identified as a sire of future AI bulls, and if his semen is used immediately to inseminate elite cows and heifers his first sons will be born when he is about 63 months of age. ٧٠

71 Timeline of an aggressive AI breeding program based on the use of genomic bulls as sires of sons (from Schefers and Weigel, 2012). three-fold reduction in generation interval Prove at 12 months ٧١

72 In an aggressive breeding program based on genomic selection A young bull can be identified as a sire of future AI bulls as early as 1 or 2 months of age, and as soon as he reaches sexual maturity his semen can be used to inseminate elite cows and heifers (Schaeffer, 2006). His first sons will be born when he is roughly 21 months of age It means that we can achieve a three-fold reduction in generation interval in the sires to produce sons selection pathway. ٧٢

73 Another application of genomic selection To identify potential dams of future AI bulls at a young age and propagate them via embryo transfer (ET) or in vitro fertilization (IVF) as yearling heifers. Reduction of generation interval for the dams to produce sons selection pathway From about 38 months to roughly 22 months. ٧٣

74 An obvious extension of the aforementioned strategy is to use genomic selection to identify potential dams of future AI bulls at a young age and propagate them via embryo transfer (ET) or in vitro fertilization (IVF) as yearling heifers, as opposed to waiting for completion one or more lactation records. In this manner, the generation interval for the dams to produce sons selection pathway can also be reduced, from about 38 months to roughly 22 months. Furthermore, the GPTA values of elite cows and heifers based on genomic testing have much greater REL than their traditional PTA values based on pedigree and performance data only, and this further accelerates the rate of genetic progress per year. ٧٤

75 Genomic Selection of Females Dams to produce daughters selection pathway poor accuracy low selection intensity High rates of culling due to illness, injury, or infertility have typically prevented the culling of genetically inferior replacement heifers. But the culling rates on modern, well-managed free-stall operations tend to be low, and widespread usage of gender-enhanced (sexed) semen has generated an excess of replacement heifers ٧٥

76 Genomic Selection of Females Dairy producers have an opportunity to improve the genetic potential of their herds By culling inferior females at a young age By Identifying superior female at a young age More importantly They can significantly reduce the feed costs associated with rearing animals that are unlikely to perform at a profitable level once they reach lactating age. ٧٦

77 factors that determining decision-making in designing breeding programs 1. Reproduction capacity 2. Social (infra)structure 3. Optimization aimed for 4. Traits in aggregate genotype 5. Genetic parameters ٧٧

78 Different goals in a breeding program Maximization of genetic gain In short term In long term Genetic gain In one single trait In a combination of traits Maintaining genetic variance in a population Avoiding inbreeding ٧٨

79 Different goals in a breeding program The goals clearly has an impact on steps 2 and 6 the criteria for evaluation of alternative breeding schemes (step 9) ٧٩

80 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. 9. Compare alternative combined programs ٨٠

81 Optimization aimed for Maintaining genetic variation & avoidance of inbreeding Put restrictions on the number of breeding animals to be used (steps 7 and 8) ٨١

82 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. 9. Compare alternative combined programs ٨٢

83 3- Optimization aimed for For some production systems, uniformity of the product is very important. Crossbreeding is an important way to obtain more uniform products ٨٣

84 Different components of genetic Different factors interact: gain interact For example, one could try to increase selection intensity, but the result is that breeding animals can be less rapidly replaced when fewer young animals are selected, and the generation interval is increased ٨٤

85 The most important interactions Generation interval versus selection accuracy Generation interval versus selection intensity Balancing different traits ٨٥

86 Generation interval versus selection accuracy Selection young animals It will not only lead to short generation intervals, but may also imply lower selection accuracy Because young animals have generally less information available (no repeated records, maybe no own performance, no progeny test) ٨٦

87 Generation interval versus selection intensity When More young animals are retained as breeders High replacement rate is applied The generation interval may be shorter But selection intensity will also be lower Because more animals of the newborn generation are needed as replacements. ٨٧

88 factors that determining decision-making in designing breeding programs 1. Reproduction capacity 2. Social (infra)structure 3. Optimization aimed for 4. Traits in aggregate genotype 5. Genetic parameters ٨٨

89 4- Traits in the aggregate genotype What is Aggregate genotype? Aggregate genotype contains all traits that influence (economic) efficiency of production A weighted sum of genotypic values for all traits Genotypic values of traits can not be measured directly on animals It is possible to estimate genotypic value by using phenotypic information on the animals (BLUP or BLP) ٨٩

90 Aggregate genotype Characters that have to be known for all interested traits in aggregate genotype Economic values Genetic parameters Genetic variance and covariance among all traits (r g ), h 2 and magnitude of additive and non-additive genetic effects (heterosis) In conclusion the traits included in the breeding goal influence the structure of recording system in breeding programs (steps 4, 5 and 6) ٩٠

91 A procedure to develop a breeding program (Harris et al. 1984) 1. Describe the production system 2. Formulate the objective of the system 3. Choose a breeding system and breeds 4. Estimate selection parameters and economic values 5. Design an animal evaluation system 6. Develop selection criteria 7. Design a mating system for selected animals 8. Design a system for expansion, dissemination- of genetic superiority. ٩١

92 factors that determining decision-making in designing breeding programs 1. Reproduction capacity 2. Social (infra)structure 3. Optimization aimed for 4. Traits in aggregate genotype 5. Genetic parameters ٩٢

93 5- Genetic parameters h 2 r g Relative magnitude of additive and nonadditive genetic effects. What is the influence of these parameters on the structure of breeding programs? ٩٣

94 Genetic parameters and structure of breeding programs It determine how much observations are needed for accurate selection (step 5 and 6) e.g. with high h 2 (above 0.5) : mass selection with low h 2 large offspring groups are needed for accurate EBV ٩٤

95 5- Genetic parameters Relative magnitude of additive and non-additive genetic effects: With relatively large additive effects favor purebreed or pure-line selection. With relatively large dominant effects favor the use of crossbreeding. pure-breed or pure-line selection. It should also considered G*E interaction ٩٥

96 The general structure of breeding programs ٩٦

97 The general structure of breeding programs Dairy cattle vs. poultry In describing structure of breeding programs, one looks for: 1. The different selection paths distinguished 2. The (major) type of information sources included in estimating BV 3. The ownership of (potentially) selected animals ٩٧

98 1. Considering the whole population as one bath of animals Four selection paths Sire of Bulls 1-Sires to breed bull (SB) Parents of next generation Sire of dams Dam of Bulls 2-Sires to breed Dams (SD 3-Dams to breed bulls (DB) The whole Population not-parents of next generation Dam of dams 4-Dams to breed dams (DD) In a crossbreeding situation these selection paths can be distinguished within each line ٩٨

99 2. By looking to the reference book such as falconer Mass-selection Sib-selection Progeny testing Family- selection Direct versus indirect selection etc ٩٩

100 3. Referring to the ownership The main distinction is between animals owned by the breeding organization and Animals owned by the commercial producers ١٠٠

101 ١٠١

102 For each 1% inbreeding increase, a herd experiences: Lifetime NM$ days age at first calving days Productive Life lbs lifetime milk production lbs lifetime protein production month first calving interval 7. The cost of each additional day a dairy cow is open, beyond the herd's voluntary waiting period, can range from $3.19 to $5.41 per cow per year ١٠٢

103 Nucleus animals The animals for the production of next generation. In dairy cattle: All bull sires (SS) All bull dams (DS) In poultry breeding pure lines The poultry breeding organization They own all nucleus animals Dairy cattle breeding organization They might own only the sires and some cows. ١٠٣

104 The general structure of dairy cattle breeding programs Males to breed nucleus replacements Χ Females to breed nucleus replacements Males Progeny nucleus females Males to breed base replacements Χ Females to breed base replacements Males Progeny base females ١٠٤

105 Dairy cattle breeding programs You can identify : Selection paths ١٠٥

106 1. Different selection paths Four selection paths Sire of sires Sires to breed sire (SS) Parents of next generation Sire of dams Dam of sires Sires to breed Dams (SD) Dams to breed sires (DS) The whole Population not-parents of next generation Dam of dams Dams to breed dams (DD) In a crossbreeding situation these selection paths can be distinguished within each ١٠٦ line

107 Dairy cattle breeding programs You can identify four selection paths. The figure reflects an open nucleus scheme: nucleus animals are owned by the breeding organization, but superior females in base population can enter the nucleus. ١٠٧

108 The general structure of dairy cattle breeding programs Males to breed nucleus replacements Χ Females to breed nucleus replacements Males Progeny nucleus females Males to breed base replacements Χ Females to breed base replacements Males Progeny base females ١٠٨

109 Dairy cattle breeding programs You can identify four selection paths. The figure reflects an open nucleus scheme: nucleus animals are owned by the breeding organization, but superior females in base population can enter the nucleus. If the latter possibility is not included, the structure is called a closed nucleus scheme. ١٠٩

110 Dairy cattle breeding program In dairy cattle, the breeding and production populations are not strictly separated. Superior cows from the production population can enter the breeding population, they are selected as bull dams. Genetic progress created in the breeding program is transferred to the dairy farms by the sale of semen of progeny tested bulls to the farmers. The primary source of income for dairy cattle breeding companies: The sale of semen is In addition, a limited number of embryos from the breeding population are sold to the dairy farmers. ١١٠

111 In dairy cattle breeding program Selected male (young bulls) Superior male (Proven bulls) ١١١

112 Young bulls in dairy cattle breeding program Selected male (young bulls) They are selected based on pedigree They usually are progeny tested in the base pop. by a limited number of insemination The bulls have to wait for their EBV from Bulls with high EBV are used as proven bulls Proven bulls are used to breed the next generation of base animals. ١١٢

113 Poultry breeding programs A main characteristic of poultry breeding programs is: Using crossbreeding and as a consequence, different levels in the structure. The structure is often called a pyramidal structure AT top: relatively few animals in nucleus herds Pure bred animals which are bred for a specific goal which might differ between lines Production traits in sire line, reproduction and production traits in dam lines At bottom: The crossbred animals in commercial farms. Animals which are responsible for the production of products. In middle: there might be several layers. To enable the production of sufficient parents to produce commercial animals To generate the desired crosses ١١٣

114 Poultry breeding programs A main characteristic of poultry breeding programs is the use of crossbreeding and as a consequence, different levels in the structure. AT top: few animals in nucleus herds At bottom: The crossbred animals in commercial farms. In middle: there might be several layers. Relatively small # of animals are needed to generate the genetic progress Relatively large # of animals is needed for production. ١١٤

115 The general structure of poultry breeding programs (4-ways cross) Elite Breeders Nucleus herds Pure-line breeding A Pure-line Breeding B Pure-line Breeding C Pure-line breeding D Multiplier 1 herds GGP (grand-grand parents) A female bred to A males GGP (grand-grand parents) B female bred to B males GGP (grand-grand parents) C female bred to C males GGP (grand-grand parents) D female bred to D males Multiplier End uses Multiplier 2 herds Multiplier 3 herds Commercial producers GP GP B female bred to A males D female bred to C males A*B C*D P C*D females bred to A*B males AB*CD Broilers/laying hens ABCD ١١٥

116 A similar scheme is possible with 3-way crosses With a 2-way cross, one multiplier layer can be omitted. ١١٦

117 The general structure of poultry breeding programs (4-ways cross) Elite Breeders Nucleus herds Pure-line breeding A Pure-line Breeding B Pure-line Breeding C Pure-line breeding D Multiplier 1 herds GGP (grand-grand parents) A female bred to A males GGP (grand-grand parents) B female bred to B males GGP (grand-grand parents) C female bred to C males GGP (grand-grand parents) D female bred to D males Multiplier End uses Multiplier 2 herds Multiplier 3 herds Commercial producers GP GP B female bred to A males D female bred to C males A*B C*D P C*D females bred to A*B males AB*CD Broilers/laying hens ABCD ١١٧

118 A similar scheme is possible with 3-way crosses With a 2-way cross, one multiplier layer can be omitted. The multiplier layers are used to produce sufficient pure line animals for the production of crossbred animals ١١٨

119 In poultry breeding an unusual process of mating between brothers and sisters produces the inbred hens This is a kind of self-fertilization like in corn, but is only half as fast. Nature guards against inbreeding as it produces some weaklings. This enables the poultry breeder to reveal weaknesses in the stock so they can be eliminated. ١١٩

120 How to develop inbred lines? Inbred lines are developed by starting with: an excellent standard bred strain Then continue with brother-sister mating for five generations At each generation: The birds with the bad traits are eliminated Those with good traits are used for the next round of sibling mating. ١٢٠

121 How to develop the best combination of inbred lines? When the inbred lines have been developed, they are then tested to see: how well they cross with other inbred lines to give a blend of desired qualities without undesirable weaknesses. After the best single crosses have been discovered, the best combination of two single crosses is selected by a similar testing process which will produce a four-way cross. ١٢١

122 The four-way cross blends all of the good qualities of the four inbreds together to make a superior final product. Only through inbreeding and intensive selection can fixation of desired characteristics be produced. ١٢٢

123 Population structure With large populations of birds under selection it is possible to produce grandparents directly from pedigree stock, a scheme not followed by many other breeders that used a great grandparent multiplier stage. By having a very large pedigree population allowed the move from pedigree to grandparent in a single multiplier step and also to select intensively at the pedigree level. Furthermore the procedure of not replacing the total pedigree population every time birds are select permits the practice of more intense selection and to utilize birds that are 3 to 4 standard deviations above the mean as long as they maintain productivity. This was a unique program based on what other breeders ١٢٣ were doing at the time.

124 فرآيند توليد جوجه گوشتي گله هاي لاين گله هاي اجداد گله هاي مادر گله هاي گوشتي ١٢٤ 124

125 ١٢٥

126 ١٢٦

127 Selected Pedigree Stock لاین خالص : ١ Great-Grandparent Stock : گلھ ھاي بدل لاین یا GGP ٢ Grandparent Stock : گلھ GP ٣ Parent Stock گلھ مادر : ۴ Broilers or Pullets گلھ جوجھ ھای گوشتی یا تخمگذار: ۵ ١٢٧

128 Parameters to evaluate a breeding program The increase in efficiency of production The increase in the economic revenue. 1. The cost of running different scheme 2. The cost of production 3. The cost of running a nucleus herd 4. The cost of collecting data ١٢٨

129 Evaluation of breeding program Long-tern genetic gain vs short- term genetic gain. The long-term gain is influenced by the rate of inbreeding in the population and the reduction in genetic variance as a consequence of selection and inbreeding The short-term genetic gain is also important for breeding organization, because 1. This affects the competitive position of breeding organization 2. It is important for individual producers In determining the optimum scheme the short and long term genetic gain need to be weighted. ١٢٩