Impact if hyperprolific line of litter size in multiplication herd

TVRDOŇ, Z., HUMPOLICEK, P.: Impact if hyperprolifi c line of litter size in multiplication herd. Acta univ. agric. et silvic. Mendel. Brun., 2009, LVII, No. 2, pp. 151–154 The hyperprolifi c line is considered to be maximally eff ective in pursuit of progress in sow’s reproduction. Hyperprolifi c line effi ciency is commonly evaluated in regard of breeding herd progress. We decided to study how eff ective it is with respect to increasing of litter size in multiplication herd. Our study is specifi c by using the data from practice, concretely it is based on the information about the ancestor of sows in multiplication herd. The ancestors could be the member either hyperprolifi c line or normal line. The information about performances of sows breed in multiplication herd was known. The mixed linear models in SAS for Windows 9.1.2. were conducted to statistical analysis. Our results indicated that no signifi cant eff ect on litter size was achieved by selection criteria used in the hyperprolifi c line creation. In studied population no diff erences between TNB, NBA or NW were found on the 1st as well as on the 1st–5th litters. As we have mentioned above, the study is specifi c by using the data from practice. Therefore the studied population size is limited. It is necessary to take into consideration when the results are applied. Nevertheless, the results shown that other studies with larger population should be done to reevaluate the selection criteria. pigs, selection, reproduction, hyper prolifi c line The increasing of reproduction, particularly increasing of the litter size, by means of conventional breeding methods as well as modern methods based on the molecular genetics has not desired eff ect. It is caused mainly by the low heritability and not achieving of intense selection in practice as well as complexity of reproduction (Rothschild and Bidanel, 1998). Recently, the creation of hyper prolifi c line combined with the selection based on the evaluation of breeding value is believed to be very eff ective. In sows, the success of direct selection based on the evaluation of breeding value on litter size has been confi rmed for instance by Holl and Robinson (2003). In recent years, the large number of studies on QTL and gene markers infl uencing the reproduction was carried out. Progress in QTL mapping and gene markers study is purveyed in publication of Rothschild et al. (2007). The objective of this study was to estimate the eff ect of creation of hyper prolifi c line in breeding herd on the litter size of sows in multiplication herd. MATERIALS AND METHODS Population and Data Collections The study is based on the data collected from the breeding herd and mainly from commercial multiplication herd. From breeding herd the information about the ancestor membership in hyperprolifi c line were known. Studied population consists of 176 purebred Czech Large White sows originated from one breeding herd from which they were moved at age of 6 months to one multiplication herd. All sows included in the study were breed under the same living and breeding conditions. The ancestors of this sows could be the member either hyperprolifi c line or normal line. The data about their performance were collected during last fi h seasons. As the litter size is considered as most important trait in Czech Large White sows, we focused on the total number of piglets born (TNB) defi ned as the number of all fully formed fetuses expelled at farrowing, dead or alive; number of piglets born alive (NBA) defi ned as the number of piglets alive immediately af152 Z. Tvrdoň, P. Humpolicek ter birth and by the number of piglets weaned (NW) defi ned as the number of piglets available on the day post weaning.