Open Nucleus Breeding Systems Research Articles

Validation of the Indigenous Technical Knowledge of Cattle Pastoralists of Andhra Pradesh and Telangana, India

Indigenous technical knowledge (ITK) of livestock breeding is often tacit and not necessarily expressed in conventional forms of scientific research and documentation. Indigenous livestock breeding systems rely mostly on qualitative traits than pure quantitative qualities. Qualitative traits are difficult to measure and most of the indigenous knowledge systems are in forms of qualitative traits. The lack of documentation and predominant qualitative nature makes it difficult to validate the ITK related to livestock breeding. In this context a study was conducted to examine the traditional breeding practices associated with two heritage cattle breeds of the Deccan Plateau region of India. The study examines the criteria used for selection of the breeding bulls of the indigenous Poda Thurpu and Nallmala-Pasa/Kamma, cattle breeds native to the study area. Results of the study identifies fourteen traits specific to breeding bulls and four traits that are generic to the breeding stock/cows. These traits/characteristics are ‘deemed desirable’ by the local cattle breeders for the ‘heritage breeds’, believed to have been bred and managed by them for generations. Observations of the present study supports the notion that traditional breeders of heritage breeds lay more emphasis on qualitative traits (ability to warding-off predators, fending off-springs, coat colour and texture, gait of the animal, temperament, and response and obedience to instructions of the master) than quantitative traits. It was found that local breeders give significant importance to the fertility of bovine bulls than cows. Breeding bulls are meticulously chosen with extreme caution and care, following a very long and meticulous selection process that could last for four years. Traditionally local cattle breeders of the study follow open nucleus breeding system for breeding and are strictly against promotion of inbreeding among their cattle herds. Only men are involved in cattle breeding in the study area and women usually stay away.

Optimal open nucleus breeding system for long-term genetic gain in the Pacific white shrimp using genomic selection

The open nucleus breeding system (ONBS) has been widely employed in livestock breeding and has demonstrated a desirable genetic gain compared to the traditional closed nucleus breeding system (CNBS). However, no related study and application for ONBS exist on aquatic animal breeding. The present investigation simulates the family-based ONBS with different proportions of introduced multiplier individuals used as parents of the nucleus population (NP) and CNBS schemes for the harvest body weight of the Pacific white shrimp (Litopenaeus vannamei). The multiplier population (MP) comprised progenies from eight families with high estimated breeding value (EBV) or genomic EBV (GEBV) of NP of the previous generation. ONBS was assigned three proportions (10%, 30%, and 50%) of the introduced MP individuals. The short-term selection (G0 to G10) and long-term selection (G0 to G20) were performed for CNBS and ONBS schemes using pedigree-based best linear unbiased prediction (PBLUP) with the A relationship matrix from the pedigree or single-step genomic BLUP (ssGBLUP) with the H relationship matrix integrating SNP markers and pedigree. The genetic gain of body weight and inbreeding coefficient of NP for eight breeding schemes with CNBS_PBLUP (CP), CNBS_ssGLUP (CS), ONBS_PBLUP (OP10, OP30, OP50), and ONBS_ssGBLUP (OS10, OS30, OS50) with three proportions of the introduced MP individuals were calculated. Compared to CP, genetic gains for the three OP schemes increased by 7.68 to 11.27% after short-term selection, and by 2.51 to 5.79% after long-term selection. In comparison to CS, genetic gains for the three OS schemes increased by 8.21 to 8.96% after short-term selection, and from 4.46 to 5.87% after long-term selection. The ONBS schemes achieved higher genetic gains than the corresponding CNBS schemes whether using genomic or pedigree information. The advantage of ONBS over CNBS is reduced after long-term selection. Genetic gains for the three OS schemes increased by 9.77 to 14.06% after long-term selection compared with the corresponding OP schemes. Furthermore, no significant difference (P > 0.05) in genetic gain was revealed among the ONBS schemes after either pedigree-based or genomic selection. Inbreeding coefficients for the three OP schemes increased from 59.45 to 70.98% compared with CP, whereas inbreeding coefficients for the three OS schemes increased from 24.72 to 32.22% compared with CS. Besides, after long-term selection, inbreeding coefficients for the three OS schemes decreased from 13.13 to 14.79% compared with the corresponding OP schemes. In a nutshell, ONBS using introduced MP individuals has great promise in the selective breeding program of L. vannamei. Genomic information has more potential to improve selection response and control inbreeding level than pedigree information when applying ONBS.

Assisted reproductive technologies (ARTs) in Mithun (Bos frontalis): What progress has been made so far? An overview.

Mithun, a unique bovine species, endemic to parts of North East India and plays an important role in the socioeconomic, cultural and religious fabrics of the local tribal population. To date, Mithuns are reared in a traditional free-range system by communities and increased deforestation, agricultural commercialization, disease outbreaks and indiscriminate slaughtering of elite Mithun for table purposes have significantly decreased its habitat and the elite Mithun population. Greater genetic gain is achieved with the implementation and effective use of assisted reproductive technologies (ARTs); however, presently it is limited to organized Mithun farms. At a slow pace, Mithun farmers are adopting semi-intensive rearing systems and interest in the use of ARTs is gradually escalating in Mithun husbandry. This article reviews the current status of ARTs such as semen collection and cryopreservation, estrus synchronization and timed artificial insemination (TAI), multiple ovulation and embryo transfer and in vitro embryo production and future perspectives in Mithun. Mithun semen collection and cryopreservation have been standardized, and estrus synchronization and TAI are suitable technologies that can be easily implemented under field conditions in near future. The establishment of an open nucleus-breeding system under community participatory mode along with the introduction of the ARTs is an alternative to the traditional breeding system for rapid genetic improvement of Mithun. Finally, the review considers the potential benefits of ARTs in Mithun and future research should include the use of these ARTs which will provide additional opportunities for improved breeding regimens in Mithun.

Cattle and Buffalo Genetic Resources of India

There are 50 registered breed of cattle and 19 breeds of buffalo in the country, these breeds are well adapted to diverse climate of the country and contributing significantly to the livelihood. India possesses 193.4 million cattle and 109.85 million buffalo in the year 2019. The crossbred and buffalo population has increased all the time since the livestock census initiated. Among the cattle and buffalo, 52% cattle and 45.4% buffalo population are non-descript and need to be defined on priority so their development programs can be initiated. India is home of best breeds of buffalo in the world i.e. Murrah and Sahiwal, Gir, Ongole and Tharparkar breeds of cattle. Mehsana and Niliravi are the breeds of buffalo those are equally good in performance in the country. Gir breed of cattle and Murrah breed of buffalo had maximum heads in the country. Breed wise trends during the years 2013-2022, showed that among the 37 cattle breeds included in breed survey/census, 15 are showing increasing trends and 22 showed declining trends. In buffalo, 13 breeds were included in breed survey/census, 4 are showing declining trends and 9 showed increasing trends. For improving the bovines in the country, we need to define non-described bovines on priority and registered unique population as distinct breed, if eligible, accurate breed census/survey, performance recording system at farmers door, ensure availability of superior germplasm, more population to be covered through Artificial Insemination and establishment of breed societies and breed nucleus farms adopting open nucleus breeding system.

Genetic and genomic evaluation of different breeding strategies using stochastic simulation in Iranian buffalo (

Context Despite the importance of buffalos to income and food needs, there has been little attention to the simulation of breeding programs using different strategies in the Iranian buffalo population. Aims The present study aimed to evaluate different breeding strategies in Iranian native buffalo by using stochastic simulation, and to determine the most appropriate strategy for Iranian buffalo breeding. Methods Different breeding scenarios were simulated for sensitivity of outcomes to the nucleus population size and selection design. Two systems of closed and open nucleus breeding schemes were simulated. Three different nucleus sizes, the optimal fraction of nucleus dams born in the base, and the appropriate fraction of base sires born in the nucleus were considered. Four selection designs were considered: random, phenotypic, best linear unbiased prediction (BLUP), and genomic selection. Key results The results indicated that in different population sizes and both open and closed nuclei, the average total genetic value was higher in genomic selection than in other selection designs. The total genetic value was higher in open nucleus than closed nucleus breeding schemes regardless of selection design. The highest mean of total genetic value was estimated at 91.53 in the optimal nucleus size of 15% of base population for the genomic selection approach and the open nucleus breeding system. In all nucleus population sizes, the highest inbreeding was obtained for selection based on BLUP, followed by genomic, phenotype and then random selection. Conclusions Overall, the application of open nucleus breeding schemes along with genomic selection is recommended for improving buffalo productivity. Implications Selection strategies used in Iranian buffaloes have so far been based on phenotypic information; however, obtaining genetic information could improve genetic progress in the Iranian buffalo population.

English

English

Diversity in morphology and pigmentation patterns of local Pabna cattle in Bangladesh

The study was aimed to reveal the morphological features of local Pabna cattle at Bangladesh Livestock Research Institute (BLRI), Regional Station, Sirajganj and community levels. Data of various morphological features were collected from total 24 cattle from on-station and 8 cattle from community. It was observed that most of the morphological features were not varied between the studied cattle populations except body length, height at wither, pelvic length, tail dock circumference and mouth circumference (p <0.05). Pigmentation pattern revealed that light red was dominated for coat color in both cattle population while black color was most frequently observed in muzzle, eyelid, eyelash, horn, hoof, dew claw and tail switch. As most of the phenotypic observation and pigmentation patterns were unique between two existing Pabna cattle population, an open nucleus breeding system might be enhanced the desire dairy breed development from those cattle population regarding the uniformity of morphological features.Res. Agric. Livest. Fish.4(3): 201-208, December 2017

Breeding systems for genetic improvement of dairy goats in smallholder production systems in Kenya

A deterministic simulation model was used to test the hypothesis that utilization of untested juvenile bucks could be an alternative to old buck strategy in dissemination of superior genetic materials in dairy goats breeding program. We compared the genetic and economic gains realised when the untested juvenile and old bucks were used to disseminate genetic materials in a two-tier closed and open nucleus breeding systems. In the untested juvenile buck strategy, 95 and 70% of nucleus and commercial does, respectively, were mated to the untested juvenile bucks. In the old buck strategy, all the females in the nucleus and 70% of commercial does were mated by old bucks from the nucleus. In the open nucleus system, 20% of the does born in the commercial sector were recruited into the nucleus to produce nucleus does of does. Utilization of untested juvenile bucks realised 5.92 and 7.30% more annual returns and profitability per doe, respectively compared to old buck strategy. The old buck strategy, however, outperformed untested juvenile buck strategy by 23.37 and 14.85% in total annual genetic gain in closed and open nucleus breeding systems, respectively. Comparison between closed and open nucleus breeding systems demonstrated that open nucleus systems are superior to closed nucleus systems both in genetic and economic response. These findings therefore demonstrate that untested juvenile bucks could be an alternative to old buck strategy when economic viability of the breeding program is the main focus. There is, however, need to strike a balance between economic and genetic gains in the breeding program.

N Dama Cattle Conservation: The Potential Roles of Artificial Insemination and the National Policy

Regular access to genetically superior bulls from an open nucleus breeding system is an impetus for N’Dama cattle utilization and conservation. However, shortage in the number of bulls that could be distributed to the farmers for subsequent breeding remains a challenge in some countries of West Africa. In this regard, the potential benefit of artificial insemination (AI) and the roles of national policy were assessed. The open nucleus-breeding scheme of International Trypanotolerance Center (ITC) in the Gambia was used as a case study and the research questions were answered with literature review, focus group discussion, and Likert-scale questionnaire. Introduction of AI into the breeding scheme of N’Dama cattle can create higher selection intensity and promote a wider dissemination of genetic gain made at the nucleus. With improved AI techniques, a better use of improved N’Dama bulls can be achieved. Notwithstanding, there are concerns about low pregnancy rate, quality of the semen, inadequate knowledge of AI technicians, and the regular availability of quality bulls. For the Gambian national policy, the environmental component is the most relevant for conservation of N’Dama cattle. This can be buttressed with more flexibility and a clearer communication of the objectives through workshops and local media.

Biotechnology applications for the sustainable management of goat genetic resources

Goats are usually raised under harsh environmental conditions and have a unique ability to take advantage of marginal areas. The diversity of goat genetic resources throughout the world reflects their adaptation to very different production systems, with a predominance of native breeds, often in danger of extinction, very well adapted to local conditions. There is an urgent need to establish programs aimed at the characterization, conservation and sustainable utilization of those genetic resources, and recent developments in the different branches of biotechnology may provide the opportunity for new approaches to achieve those goals. Biotechnologies can further enhance genetic improvement programs, provide tools to ensure the integrity of procedures in goat production, foster opportunities for new products to be developed and support animal health control. Of the biotechnologies currently available, genetic markers, genetic modifications and reproductive technologies are the ones with more potential for the sustainable management of goat genetic resources. For example, artificial insemination and embryo transfer/cryopreservation are essential in conservation and very useful in selection programs, while genetic modifications are primarily applied to obtain recombinant proteins with pharmaceutical or nutraceutical properties. Genetic markers, including neutral, sex-specific and non-neutral markers, as well as single nucleotide polymorphisms (SNPs), are essential for the appropriate management of goat genetic resources, especially in activities related to their characterization and conservation, and specific genetic markers, such as polymorphisms in the αs1-casein locus or in the PrP gene, can be used to strengthen selection programs. Recently, the availability of high-density marker panels which allow the simultaneous detection of thousands of SNPs, opened the possibility of practicing genomic selection, which could increase tremendously the rates of genetic progress currently achieved. Nevertheless, the costs involved are high, and the appropriate definition of breeding objectives, including fitness-related traits, remains a crucial issue, especially for goats. The integration of biotechnologies in goat breeding programs in extensive systems is challenging, as it requires an appropriate organization of the breeding and production systems, which could be based on a simplification of performance recording and the adoption of a flexible open nucleus breeding system.

Analysis of an open nucleus breeding programme for Djallonkè sheep in the Ivory Coast. 2. Response to selection on body weights

AbstractA selection programme was set up in 1983 in the Ivory Coast to improve the growth and live weight of the indigenous Djallonkè sheep using an open nucleus breeding system. Selection was based on male individual weights at 80, 180 and 365 days of age. Multiple sires were used in farmers' flocks. Individual animal model, using average numerator relationship was used to estimate breeding values from which genetic trends were derived. This paper reports results of the analyses of 10 417 records of 80-day weights (WT80) of lambs born between 1984 and 1992 from 29 participating farmers, and 1978 and 849 records on 180- (WT180) and 365- (WT365) day weights, respectively, of lambs from the nucleus. Phenotypic trends exhibited substantial annual fluctuation during the study period. The heaviest weights were obtained in 1986 (10·1 kg) for WT80, 1984 (23·3 kg) for WT180 and 1985 (33·7 kg) for WT365. There was an annual decline of 152 g (P<0·05) in WT80 mainly (–180 g/year) due to negative environmental trend. The phenotypic and environmental trends for WT180 were –703 and –721 g/year, respectively, while the corresponding values for WT365 were –931 and –956 g/year. Overall mean weights of the ram lambs at the three ages were 9·9, 23·3 and 33·7 kg, respectively in the base year and 9·3, 17·8 and 28·2 kg, respectively in the final year. Breeding values increased by 28, 11 and 14 g/year for WT80, WT180 and WT365, respectively. Results of this study indicate that genetic progress can be made in growth performance of Djallonkè sheep if reasonable levels of animal management as well as selection pressure are maintained.

Prediction of effective population size in open nucleus breeding systems

A prediction equation for the effective population size in open nucleus breeding systems was derived, in terms of the cumulative effect of selection on gene frequency. Monte Carlo simulation was carried out to check the equation. From the results, it was found that the derived equation is applicable to most practical situations.

A method of using a genetic algorithm to examine the optimum structure of the Australian sheep breeding industry: open-nucleus breeding systems, MOET and AI

A genetic algorithm was evaluated as a means of using a computer model to determine the optimum structure of the Australian sheep breeding industry. The model simulates an open-nucleus 3-tiered sheep breeding system to investigate the benefit of strategies such as multiple ovulation and embryo transfer (MOET) and artificial insemination (AI) in terms of both genetic improvement and dollar values. The model indicated that both MOET and non- MOET systems benefit from an open nucleus, and both could also benefit from the promotion of some ewes from the commercial flocks. However, MOET systems require a relatively large number of rams, whereas non- MOET systems should have a smaller number of rams despite the much larger number of ewes needed. Under the conditions studied here, there was only limited advantage of MOET over non-MOET schemes. The optimum structure of the MOET, non-MOET and closed systems differ substantially. A genetic algorithm is a simple method for considering a single change (such as reproductive rate, or open v. closed) that may require major changes in the industry structure to achieve the full benefits. The method could also be of value in many other situations requiring optimisation of complex models.

A simulation study of open nucleus and closed nucleus breeding systems in a sheep population

AbstractStochastic simulation was used to compare the results of alternative breeding systems in a sheep population divided into 10 flocks of 120 ewes. The breeding systems compared were selection within closed flocks (CF), a closed nucleus system (CNS), an open nucleus system (ONS) and open nucleus systems with the selection of nucleus replacements being restricted to either nucleus born males (ONSRm) or nucleus born females (ONSRf). Selection was for a best linear unbiased prediction of breeding value for lamb live weight which had a heritability of 0·17. The open nucleus breeding systems (ONS, ONSRm, ONSRf) resulted in higher rates of genetic gain, more predictable selection responses and lower rates of inbreeding than either the closed nucleus system (CNS) or selection within closed flocks (CF). Initial genetic differences between flocks resulted in higher rates of genetic gain in the nucleus breeding systems due to the use of between flock genetic variance. In the ONS system up to 25% of nucleus sires and approximately 50% of nucleus dams were born in base flocks. Nevertheless if selection of either nucleus sires or dams was restricted to nucleus born animals there was very little change in genetic gain or rate of inbreeding.

A comparison of the rate of genetic gain and inbreeding in a Centralised and a dispersed open nucleus breeding system for sheep

Open nucleus breeding systems have been shown to result in higher genetic gains and lower rates of inbreeding than closed systems. The organisation of an open nucleus system is, however, complex and the long term success depends upon a consistency of objectives among, and strong commitment from the participating breeders. Initial genetic differences between flocks ultimately result in a greater advantage of the open nucleus system, but the short term effect, for the better flocks, is a reduction in genetic gain compared to closed flock selection. The open nucleus system also involves the physical transfer of breeding stock between flocks, which may represent a risk to sheep health.There are, at present, a number of sire referencing schemes operating in pedigree sheep populations. These schemes involve the mating of ‘reference’ sires to randomly nominated ewes in a number of flocks. The genetic links that are created between flocks enable accurate comparisons of estimated breeding values and therefore accurate selection across flocks.

Design and evaluation of progeny testing in open-nucleus breeding systems

ABSTRACTWhen comparing progeny-testing schemes with individual performance selection, one should use equivalent selection intensities and population structures in the two systems. Adapting formulae from open-nucleus theory, the relative efficiency of progeny testing has been tested for a range of heritabilities, fertility levels, upward gene-transfer rates, mating ratios and numbers of sires selected. In sheep and beef cattle breeding, the heritability of the trait under consideration has usually to be very low to make progeny testing worth-while. High fertility increases genetic gains but does not change the relative efficiency of progeny testing. Opening the nucleus to females from the base increases genetic gains and reduces relative efficiency of progeny testing, both effects being of small magnitude. For fixed mating ratios, only a small fraction of females should be in the nucleus, but for fixed sire numbers approximately one-third of the population should be mated to proven sires. In these analyses, variances were adjusted for the effects of repeated selection and for the effects due to mixing groups with different means. This adjustment did reduce absolute genetic gains, but did not change conclusions on progeny testing efficiency and optimum design.

Single and two-stage selection on different indices in open nucleus breeding systems

Single and two-stage selection on different indices in open nucleus breeding systems

Single and two-stage selection on different indices in open nucleus breeding systems

Single and two-stage selection on different indices in open nucleus breeding systems

Effects of reduced variance due to selection in open nucleus breeding systems

In the design of breeding programs the consideration of open nucleus breeding systems may result in a useful alternative. The available theory dealing with these systems assumes constant parameters, but a more exact approach would take into account the possible changes in genetic variance. Numerical evaluation of formulae allowing for loss of genetic variance due to linkage disequilibrium and increase of variance due to mixing groups with different breeding values, suggests that optimum transfer rates, as predicted from the constant parameter theory, are in close agreement with the actual values; however, genetic gain is overestimated by about 20 % in common cattle and sheep nucleus breeding schemes for traits with high heritability, but less for traits with low heritability. The advantage of opening the nucleus is approximated well by constant variance theory.

Open nucleus breeding systems

SUMMARYA theoretical analysis of open nucleus breeding systems, in which there is some introduction of breeding females to the sire breeding nucleus, is presented. Numerical analysis of a discrete generation model shows that the rate of genetic gain may be increased by 10 to 15% by opening the nucleus when selection intensity in females is low. In sheep and beef cattle breeding the optimal structure would be to have about 10% of the population in the nucleus, to get half of the nucleus female replacements from the base population, and to use all nucleus-born females not needed as nucleus replacements for breeding in the base population. The genetic gain, however, is not very sensitive to variation in these parameters. The rate of inbreeding in such an open nucleus would be about half that in a closed nucleus of the same size.