Do Crossbreeding using Exotic Breeds in Goat is the Right Solution for a Low-input Production System in Ethiopia? : A Review

Analysis and evaluation of the previous genetic improvement attempts and their fruition are paramount to make the right decision in the future. Hence, this paper reviews the status of goat genetic improvement programs through quantitative evidence and elucidates how it can be implemented in the future through an intensive literature review. Goat genetic improvement through crossbreeding was initiated early in 1975. However, most crossbreeding programs have lacked analysis of the existing resources and infrastructure and also lack long-term strategies. As a result, crossbreeding program was discontinued without significant contribution due to incompatibility of the exotic genotype with low-input production systems. On the other hand, the moderate to high genetic variation within a population open the window for within-breed selection. Accordingly, a well-designed within-breed selection program was initiated late in 2013 for specified breeds. Currently, governmental and non-governmental institutions plan to scale up community-based within-breed selection program. Besides, the efficiency of assisted reproductive technologies in goat genetic improvement was evaluated by ICARDA and reported a moderate achievement. However, the application of molecular technologies in Ethiopia is only limited to diversity studies. Nevertheless, there is an opportunity to use molecular technologies to enhance the genetic progress of a genetic improvement program. In conclusion, the expected benefits from crossbreeding program were not obtained and will not be obtained under the existing low input-production system. Therefore, a within-breed selection program would be an ideal option for the existing low-input production system if integrated with assisted reproductive and molecular technologies.

Genetic diversity and SSR markers development of ancient Camellia sinensis in Sandu County of Guizhou Province

Background: The genetic abundance of ancient tea germplasm has been preserved in the long evolution process, which provides valuable resources for the protection and breed selection of ancient tea germplasm. However, the limited studies related to the genetic diversity of ancient tea germplasm restrict protection and breed selection. Therefore, the genetic diversity of ancient tea germplasm in Sandu county of Guizhou Province was explored in this study. II.Methods and Results: The genetic diversity was analyzed using phenotypes and SSR markers. The ranges for the variation coefficients of the six quantitative and seven qualitative characters were 17.76%-60.37% and 18.58%-50.64%, respectively. The ranges of diversity indices of the six quantitative and seven qualitative characters were 1.72-2.74 and 0.55-0.84, respectively. Ninety-six bands were amplified using 15 pairs of SSR primers from the 145 samples, and the average polymorphism information index was 0.66. The analysis revealed that the average values of Nei’s genetic diversity index (H) and the Shannon information index (I) are 0.26 and 0.41, respectively. Further, a genetic similarity coefficient of 0.734 shown by UPGMA dendrogram classified the 145 samples decreased into four groups. III.Conclusions: This study revealed the rich phenotypic variation and high molecular genetic diversity and the genetic diversity of the arbor is higher than that of the shrub of the ancient tea germplasm in Sandu of Guizhou province. Thus, this study not only provides a theoretical basis for the protection and breed selection but also promotes further research of ancient tea germplasm.

Accurate Diagnosis of Small Ruminant Lentivirus Infection Is Needed for Selection of Resistant Sheep through TMEM154 E35K Genotyping

Small ruminant lentiviruses (SRLV) cause an incurable multiorganic disease widely spread in sheep and goats that disturbs animal welfare and production. In the absence of a vaccine, control measures have been traditionally based on early diagnosis and breeding with virus-inactivated colostrum with segregation of seropositive animals. However, antigenic heterogeneity, poor antibody production due to low viral load, and single strain design of most available ELISA, pose a threat to SRLV diagnosis. Genome-wide association studies have described TMEM154 E35K polymorphism as a good genetic marker for selection of resistant animals in some American and European breeds. In this study, a multitargeted serological and virological screening of more than 500 animals from four different breeds (latxa, raza Navarra, assaf, and churra) attending to SRLV infection status was performed. Then, animals were genotyped to characterize TMEM154 E35K polymorphism. ELISA procedures, individually considered, only identified a proportion of the seropositive animals, and PCR detected a fraction of seronegative animals, globally offering different animal classifications according to SRLV infection status. TMEM154 allele frequency differed substantially among breeds and a positive association between seroprevalence and TMEM154 genotype was found only in one breed. Selection based on TMEM154 may be suitable for specific ovine breeds or SRLV strains, however generalization to the whole SRLV genetic spectrum, ovine breeds, or epidemiological situation may need further validation.

Productive and biological features of breeding Irish pigs of various genotypes in Western Siberia

The present work studies the productive and biological characteristics of breeding Irish pigs of different genotypes in the conditions of Western Siberia. Pure-bred selection of Large White pigs (WP) was used in the first control group and intra-breed selection of Landrace pigs (LP) was used in the second control group. The following patterns of interbreeding were used in the experimental groups: ♀WP × ♂LP (third group), ♀LP × ♂WP (fourth group). In terms of reproductive qualities, the best combination should be considered the selection of ♀WP × ♂LP, in which 8.1% (p <0.05) more piglets were obtained at 30 days, with a 10.0% (p <0.05) higher weight of the nest at 30 days and 3.6% (p <0.05) greater safety than in the first control group. The combination of breeds according to the ♀LP × ♂WP scheme contributed to an increase in the average daily 13.7% (p <0.05) gain in live weight of the resulting offspring. At the age of 4 months, piglets of the LP × WP genotype had a 10.9% (p <0.05) higher content of total protein in the blood serum than in animals of the Large White breed. The muscle tissue of Large White pigs was characterized by a 5.2% (p <0.05) higher moisture binding capacity in relation to Landrace pigs. The melting point of fatty tissue was lower in Large White pigs by 14.3% (p <0.05). The fatty tissue of LP × WP hybrids has a 10.0% higher melting point (p <0.05) in contrast to Large White pigs.

Genetic improvement of farmed animals

This 484-paged book is an extensively updated and expanded edition of the previous book by Simm, which focused on cattle and sheep. It has 14 chapters, the first chapter in the book sets the scene for modern livestock breeding, by looking at the origins and roles of today's livestock breeds. The next four chapters deal with the scientific principles of livestock improvement. Chapter 2 outlines some of the basic principles in genetics and attempts to illustrate the link between genes and the performance of individual farm animals, or populations of them. In Chapter 3 the main strategies for genetic improvement are discussed. The factors which affect responses to within-breed selection, and some of the tools and technologies used, especially for more effective within-breed selection, are discussed in Chapters 4 and 5. Chapter 6 explores in more depth how we analyse variation in farm animals. Chapter 7 discusses approaches to predicting breeding values. Chapters 8 to 13 deal with the application of these principles in practical breeding programmes in dairy cattle, beef cattle, sheep and goats, poultry, pigs and aquaculture. Finally, Chapter 14 discusses some of the key societal, technical and ethical challenges facing farm animal production in general, and animal breeding and genetics in particular. It discusses how livestock breeders, scientists and others might respond to ensure wide societal and animal benefits from future breeding schemes. There is a glossary of technical terms at the end of the book.

What affects response to selection within breeds?

In this chapter, the factors which affect responses to within-breed selection, and some of the tools and technologies used, especially for more effective within-breed selection are discussed. Highlights focused on the factors affecting rates of genetic gain, and controlling inbreeding.

Conclusions and recommendations for the future.

This chapter describes some recommendations for improving animal welfare, breed selection, feed quality, beef and milk production and quality and reducing environmental impacts in organic cattle farming systems.

Tools and technologies in animal breeding.

This chapter discussed the factors which affect responses to within-breed selection, and some of the tools and technologies used, especially for more effective within-breed selection. Highlights focused on the current reproductive technologies in animal breeding, molecular genetic tools, and modern data capture tools.

Signatures of Selection in Composite Vrindavani Cattle of India

Vrindavani is an Indian composite cattle breed developed by crossbreeding taurine dairy breeds with native indicine cattle. The constituent breeds were selected for higher milk production and adaptation to the tropical climate. However, the selection response for production and adaptation traits in the Vrindavani genome is not explored. In this study, we provide the first overview of the selection signatures in the Vrindavani genome. A total of 96 Vrindavani cattle were genotyped using the BovineSNP50 BeadChip and the SNP genotype data of its constituent breeds were collected from a public database. Within-breed selection signatures in Vrindavani were investigated using the integrated haplotype score (iHS). The Vrindavani breed was also compared to each of its parental breeds to discover between-population signatures of selection using two approaches, cross-population extended haplotype homozygosity (XP-EHH) and fixation index (FST). We identified 11 common regions detected by more than one method harboring genes such as LRP1B, TNNI3K, APOB, CACNA2D1, FAM110B, and SPATA17 associated with production and adaptation. Overall, our results suggested stronger selective pressure on regions responsible for adaptation compared to milk yield.