Analysis of the inbreeding level in the active population of pigs of different breeds in Poland. Pig breeders in Poland have made extensive use of the BLUP-AM method since 1999. The application of this method for evaluating the breeding value of pigs improves their breeding value in nucleus herds and in the general population. On the other hand, the use of many sources of information (including pedigree information) in the calculations considerably increases the risk of inbreeding. The objective of the study* was to estimate the level of inbreeding in sows and boars from the domestic pig population, which have been selected for more than ten years based on the BLUP-AM estimated breeding value. The study involved Polish Large White, Polish Landrace, Hampshire, Duroc, Pietrain and Puławska sows and boars born between 2007 and 2011. Data on a total of 16 842 sows and 977 boars representing the 6 breeds raised in Poland were collected for the pedigree analyses. During the analyzed period, the coefficient of inbreeding in sows ranged from F = 0 to F = 0.25 (14 animals). Most of the animals were non-inbred (70% in the PLW and Puławska, over 80% in the PL, Duroc and Pietrain and 100% in the Hampshire). For the boars, the coefficient of inbreeding varied from 0 to 0.1875 (1 animal). The proportion of non-inbred boars was 77% in the PLW, 91% in the PL, 63% in the Puławska, and about 80% in the Duroc and Pietrain breeds. The results point to the appropriate structure of the pig population in terms of inbreeding, which shows that the selection of animals for mating has been correct and there have been no negative consequences of using the BLUP method.
Analysis of genetic structure of Silesian horses from National Stud. The aim of the study was to analyze the genetic composition of Silesian horses bred in "Książ" National Stud basing on their pedigreesand to try to answer the following question: is the subdivision of Silesian horse population really necessary to prevent local horse breed? As the material 72 pedigrees of brood mares and stallions, born between 1991 and 2009 were used. On average, 93.1% of animals were inbred, there were 96.55% inbred stallions and 90.70% inbred mares. The mean inbreeding coefficient for all horses was 2.3%, for inbred horses it reached 2.5%. There were more inbred mares (39) than stallions (28). All 72 Silesian horses from "Książ" State Stud were related with the average relationship coefficient of 8.5%. The total and effective number of founders were 458 and 163, respectively. The total andeffective number of ancestors were 64 and 22, respectively. Among the founding breeds Thoroughbred horses predominated, the next were Oldenburg and Silesian horses, whereas among ancestors there were much more Silesian horses than Thorougbreds. All in all, the genetic diversity of the Silesian horses from "Książ" National Stud was satisfactory, however its monitoring is required because of both upward inbreeding and 100% related animals. Because the population of Silesian horses is small, less than 2,000 animals and sligtly over 1,000 animals included in conservation programme, the artifical subdivision of this population as proposed in the new breeding programme, which would result in creation of two subpopulations: “old-type” and “new-type” Silesian horses, is not recommended. For maintaining genetic diversity, it could be also possible to carefully import of semen or stallions of similar breeds, i.e. German Alt-Oldenburger horses or German Heavy Warmblood horses. The plan should also include the matings recommended within the population of all available Silesian horses of both types. The authors consider introducing such a program essential. It should be also clearly stated in the plan how large proportion of the Silesian mares population could be each year mated to Thoroughbredstallions. Division into two types implies that some fraction of new-type Silesian horses and their progeny would not be regarded as potential parents of individuals for the conservation programme.
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