THE INFLUENCE OF BREED, AGE OF BOARS AND EXPLOITATION SEASON ON THEIR LIBIDO IN CONDITIONS OF THE INSEMINATION STATION
In this study it was defined the influence of breed, age and season on libido of boars exploited in insemination station. It was found that libido of hybrids (Duroc x Pietrain), (Pietrain x Duroc) and PIC is indeed higher than that of pure breed boars Pietrain, Duroc, wbp and pbz. Boars of Pietrain and pbz breed showed changes of sexual activity according to the exploitation season. Libido of boars was significantly higher in summer and autumn. The reaction of breeders to phantom in mention seasons was 2,75 min. The fastest reaction to phantom (2,4 min.) and the indeed shortest time to start ejaculation (4,6 min.) comparing to remaining age groups was shown by boars in ages above 36 months. Specimen in this age group didn’t shown any significant changes in sexual activity in each exploitation season. Received results can find use in practice. The acquaintance of boar’s libido will permit on his rational exploitation and improvement of organization of collecting the semen.
Genetic control of complex traits, with a focus on reproduction in pigs
Reproductive traits are complex, and desirable reproductive phenotypes, such as litter size or semen quality, are true polygenetic traits determined by multiple gene regulatory pathways. Each individual gene contributes to the overall variation in these traits, so genetic improvements can be achieved using conventional selection methodology. In the past, a pedigree‐based‐relationship matrix was used; this is now replaced by a combination of pedigree‐based‐ and genomic‐relationship matrices. The heritability of reproductive traits is low to moderate, so large‐scale data recording is required to identify specific, selectable attributes. Male reproductive traits—including ejaculate volume and sperm progressive motility—are moderately heritable, and could be used in selection programs. A few high‐merit artificial‐insemination boars can impact many sow populations, so additional knowledge about male reproduction—specifically pre‐pubertal detection of infertility and the technologies of semen cryopreservation and sex sorting—should further improve global breeding efforts. Conversely, female pig reproduction is currently a limiting factor of genetic improvement. Litter size and farrowing interval are the main obstacles to increasing selection intensity and to reducing generation interval in a breeding program. Age at puberty and weaning‐to‐estrus interval can be selected for, thereby reducing the number of non‐productive days. The number of piglets born alive and litter weights are also reliably influenced by genetic selection. Characterization of genotype‐environment interactions will provide opportunities to match genetics to specific farm systems. Continued investment to understand physiological models for improved phenotyping and the development of technologies to facilitate pig embryo production for genetic selection are warranted to ensure optimal breeding in future generations.
Genetics of the phenotypic evolution in sheep: a molecular look at diversity-driving genes
Background After domestication, the evolution of phenotypically-varied sheep breeds has generated rich biodiversity. This wide phenotypic variation arises as a result of hidden genomic changes that range from a single nucleotide to several thousands of nucleotides. Thus, it is of interest and significance to reveal and understand the genomic changes underlying the phenotypic variation of sheep breeds in order to drive selection towards economically important traits. Review Various traits contribute to the emergence of variation in sheep phenotypic characteristics, including coat color, horns, tail, wool, ears, udder, vertebrae, among others. The genes that determine most of these phenotypic traits have been investigated, which has generated knowledge regarding the genetic determinism of several agriculturally-relevant traits in sheep. In this review, we discuss the genomic knowledge that has emerged in the past few decades regarding the phenotypic traits in sheep, and our ultimate aim is to encourage its practical application in sheep breeding. In addition, in order to expand the current understanding of the sheep genome, we shed light on research gaps that require further investigation. Conclusions Although significant research efforts have been conducted in the past few decades, several aspects of the sheep genome remain unexplored. For the full utilization of the current knowledge of the sheep genome, a wide practical application is still required in order to boost sheep productive performance and contribute to the generation of improved sheep breeds. The accumulated knowledge on the sheep genome will help advance and strengthen sheep breeding programs to face future challenges in the sector, such as climate change, global human population growth, and the increasing demand for products of animal origin.