Impact of hyperprolific line on litter size in multiplication herd

1 ACTA UNIVERSITATIS AGRICULTURAE ET SILVICULTURAE MENDELIANAE BRUNENSIS SBORNÍK MENDELOVY ZEMĚDĚLSKÉ A LESNICKÉ UNIVERZITY V BRNĚ Volume LVII 16 Number 2, 2009 IMPACT OF HYPERPROLIFIC LINE ON LITTER SIZE IN MULTIPLICATION HERD Z. Tvrdoň, P. Humpolíček Received: January 8, 2009 Abstract TVRDOŇ, Z., HUMPOLÍČEK, P.: Impact if hyperprolifi c line of litter size in multiplication herd. Acta univ. agric. et silvic. Mendel. Brun., 2009, LVII, No. 2, pp. 00–00 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 af- 2 Z. Tvrdoň, P. Humpolíček ter birth and by the number of piglets weaned (NW) defi ned as the number of piglets available on the day post weaning. Animal Management All sows included in the study were breed under the same living conditions. The inseminations were performed in the individual pen (1.47 m2). When the standing refl ex became quit, the sows were moved to the naturally ventilated house in range of 8 to 4 sows per pen (1.2 m2). In these groups, the sows were reared until 10 days before the supposed parturition day. To parturition, the stab lings of 2.1 m length and 0.7 m width (30 cm area for piglets were separated on both side) with heated mattress (33 °C) were intend. Only the total inseminations in the herd were performed. The inseminations were carried out twice a day with 10 hours interval / intervals always with attendance of the boar. Statistical Analyses The mixed linear models, in SAS for Windows 9.1.2. were conducted to estimate the diff erences. Independent analyses in the 1st and in the 1st–5th litter independently were carried out for each of studied trait. To get the most appropriate model the following factors were used: the affi liation of the ancestor to the hyperprolifi c or normal line; the year and season of litter; type of mating – natural mating of artifi cial insemination; and the order of litter. The boars were used as the random eff ects. Furthermore, the back-fat thickness and age at fi rst farrowing was included as linear regression in some models. Individual models are defi ned in the table I. RESULTS AND DISCUSSION Although the enormous advances in lean growth traits has almost achieved an optimal point (Webb, 1998) the development in litter size have not reached the desired level. It is due to litter size is quantitative traits controlled by several genes, along with environmental factors, and the correlations between them. Although generally the low response on the selection on the litter size is considered, the results of some studies show considerable litter size increasing as an outcome of selection (Lamberson et al., 1991; Johnson et al., 1999; Bolet et al., 2001 and Robinson, 2003). Based on the experience from other countries, the hyperprolifi c line seemed to be promising method for litter size increasing. The goal of are study was to evaluate if the hyperprolifi c line creation have desired eff ect not only in breeding herd but in multiplication herd so. Our assumption was that descendents of hyperprolifi c sows should have higher number of piglets per parturition. This is in according with breeding goal of hyperprolifi c line which is primarily focused on the litter size, teat number and average daily gain. In contrast to our assumption no considerable eff ect was observed in our population. No diff erences between TNB, NBA or NW were found on the 1st as well as on the 1st– 5th litters (Table II). When our results are assessed the small number of sows included in the study is necessary to take into account. It can negatively bias the results. On the other hand the results outlined that the breeding goal of hyperprolifi c line should be reevaluate in context of results in multiplication herds. In last decade many studies about the possible incorporation of molecular data into breeding scheme or specifi cally into selection criteria were published. Since the eff ects of gene markers observed in breeding herd or some special crossbreeding populations should not correspond to eff ects in commercial herd, the special studies on this should be performed. I: Specifi cation of used models Litters Line YS Mat OL AFF Boar BF TNB 1st FFF-LR1st–5th FFFFLRNBA 1st FFF-LR1st–5th FFFFLRNW 1st FFF- -RL 1st–5th FFFF-RF – fi xed eff ect R – random eff ect L – linear regression TNB – total piglets born NBA – piglets born alive NW – number of piglets weaned LINE – HP or N line YS – year and season of litter MAT – mating or artifi cial insemination OL – order litter AFF – age at fi rst farrowing DAM – dam of sows SIRE – sire of sows BOAR – mating boar BF – back-fat thickness Impact of hyperprolifi c line on litter size in multiplication herd 3 II: Diff erences of litter size between the sows with ancestor originated from hyper prolifi c line (HP) and normal line (N) NHP 1st litters TNB 10.88 ± 0.49 11.69 ± 0.61 NBA 10.22 ± 0.48 10.97 ± 0.58 NW 10.02 ± 0.29 10.21 ± 0.31 1st–5th litters TNB 12.39 ± 0.38 12.41 ± 0.41 NBA 11.79 ± 0.36 11.91 ± 0.38 NW 10.42 ± 0.29 10.61 ± 0.31 Note: TNB – total number of piglets born; NBA – number of piglets born alive, NW – number of piglets weaned; Values with the diff erent superscripts show signifi cance level within rows: P ≤ 0.01 (A, B); P ≤ 0.1 (*, **). IMPLICATIONS The aim of our study was to found the real impact of hyperprolifi c line selection on the litter size in multiplication herd. The study was performed under the commercial conditions and the results outlined the usefulness of creation of hyper prolifi c line. The results of our study indicate that major accent should be put on the prolifi cacy, mainly on the litter size. Otherwise the emphasis aimed to improve the production traits should be lesser. SOUHRN Vliv tvorby superplodných linií na velikost vrhu v rozmnožovacích chovech Využití super plodných linií je v posledních letech považováno za vysoce efektivní možnost zvyšování reprodukčních parametrů prasnic. Většina prací se však zabývá jejich vztahem k reprodukci přímo ve šlechtitelských chovech. Velkým přínosem naší práce je studium dopadu tvorby superplodných linií na užitkovost v rozmnožovacích chovech, které jsou důležitou součástí produkčního systému v ČR. Do studie byly zahrnuty informace o užitkovosti prasnic v rozmnožovacích chovech a jejich matek v chovech šlechtitelských s přihlédnutím k zařazení do superplodné linie. K vyhodnocení vlivu superplodné linie jsme využili smíšený lineární model. Výpočet byl proveden v programu SAS for Windows, verze 9.1.2. Žádný statisticky významný rozdíl nebyl nalezen u žádného ze studovaných reprodukčních ukazatelů. Při vyhodnocení je nutné mít na zřeteli relativně nízký počet jedinců zahrnutých ve studii. I přes neprůkaznost nalezených rozdílů považujeme za důležité, aby na tuto práci navázali další práce, které budou zahrnovat větší počet jedinců a více studovaných znaků. Za splnění těchto podmínek bude možné postihnout komplexnost vztahů mezi jednotlivými produkčními znaky. selekce, reprodukce, super plodná linie. This study was supported by the Research plan No. QH 71284 and MSM7088352101. REFERENCES BOLET, G., BIDANEL J. P., OLLIVIER, L., 2001: Selection for litter size in pigs II. Effi ciency of closed and open selection lines. Genet. Sel. Evol. 33: 515–528. HOLL, J. W., ROBINSON, O. W., 2003: Results from nine generations of selection for increased litter size in swine. J. Anim. Sci. 81: 624–629. JOHNSON, R. K., NIELSON, M. K., CASEY. D. S., 1999: Responses in ovulation rate, embryonic survival, and litter traits in swine to 14 generations of selection to increase litter size. J. Anim. Sci. 77: 541–557. LAMBERSON, W. R., JOHNSON, R. K., ZIMMERMAN, D. R., LONG, T. E., 1991: Direct response to selection for increased litter size, decreased age at puberty, or random selection following selection for ovulation rate in swine. J. Anim. Sci. 69: 3129–3143. ROTHSCHILD, M. F., BIDANEL, J. P., 1998: Biology and genetics of reproduction. Pages 313–350 in The Genetics of the Pig. CAB. International, University Press, Cambridge, UK. ROTHSCHILD, M. F., ZHI-LIANG, H., ZHIHUA, J., 2007: Advances in QTL Mapping in Pigs. Int. J. Biol. Sci. 3: 192–197. WEBB, A. J., 1998: Objectives an strategies in pig improvement: an applied perspective. J. Dairy. Sci. 81: 36–46. 4 Z. Tvrdoň, P. Humpolíček Address Ing. Zdenek Tvrdoň Ph.D., NAVOS, a. s., Čelakovského 1858, 767 16 Kroměříž, Ing. Petr Humpolíček Ph.D., Ústav aplikovaného výzkumu, Univerzitrní institut, Univerzita Tomáše Bati ve Zlíně, Nad Ovčírnou 3685, 760 01 Zlín, Česká republika, e-mail: [email protected].cz