Effects of service ram on litter size in Romanov sheep

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00027014%3A_____%2F16%3AN0000119" target="_blank" >RIV/00027014:_____/16:N0000119 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/60460709:41210/16:72325

Výsledek na webu

<a href="http://www.vuzv.cz/sites/File/_privat/16120.pdf" target="_blank" >http://www.vuzv.cz/sites/File/_privat/16120.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.smallrumres.2016.05.018" target="_blank" >10.1016/j.smallrumres.2016.05.018</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Effects of service ram on litter size in Romanov sheep

Popis výsledku v původním jazyce

The objective was to examine and quantify the effects of factors acting during the mating period (service ram, mating group) on subsequent litter size in the highly prolific Romanov breed of sheep and to propose models for the potential inclusion of this effect in mixed model equations for breeding value estimation. The basic model fitted to litter size was a single-trait repeatability animal model with fixed effect of ewe age and random effects of contemporary groups of ewes during lambing, direct additive genetic effect of ewe, permanent environmental effect of ewe and random residual. 8 modifications of the basic model examined various combinations of mating effects, contemporary group of ewes during mating and additive genetic and permanent environmental effect of service ram. When the service ram effect was analyzed without inclusion of the population relationship matrix in the model, the proportion of variance attributable to service ram was 0.081. When the relationship matrix was included in the analysis, however, service ram heritability estimates varied from 0.046 to 0.10, depending upon whether ram is permanent environmental effect, a harem effect or both were included in model. Models containing the additive genetic effect of service ram had slightly lower proportions of residual variance than models lacking this effect. Including effects of mating in the model favourably decreased deviance information criterion. Means of estimated BVs by year of birth increased across the 22 years from about 0.45-0.60 lambs per litter for female fertility and from 0.55 to 0.59 lambs per litter for BV male contribution on litter size, with only small differences among models. Results from present study demonstrate that service rams in Romanov sheep have a clearly detectable influence on litter size of their mates. Genetic parameter estimates indicate that direct selection on the service ram effect could increase litter size

Název v anglickém jazyce

Effects of service ram on litter size in Romanov sheep

Popis výsledku anglicky

The objective was to examine and quantify the effects of factors acting during the mating period (service ram, mating group) on subsequent litter size in the highly prolific Romanov breed of sheep and to propose models for the potential inclusion of this effect in mixed model equations for breeding value estimation. The basic model fitted to litter size was a single-trait repeatability animal model with fixed effect of ewe age and random effects of contemporary groups of ewes during lambing, direct additive genetic effect of ewe, permanent environmental effect of ewe and random residual. 8 modifications of the basic model examined various combinations of mating effects, contemporary group of ewes during mating and additive genetic and permanent environmental effect of service ram. When the service ram effect was analyzed without inclusion of the population relationship matrix in the model, the proportion of variance attributable to service ram was 0.081. When the relationship matrix was included in the analysis, however, service ram heritability estimates varied from 0.046 to 0.10, depending upon whether ram is permanent environmental effect, a harem effect or both were included in model. Models containing the additive genetic effect of service ram had slightly lower proportions of residual variance than models lacking this effect. Including effects of mating in the model favourably decreased deviance information criterion. Means of estimated BVs by year of birth increased across the 22 years from about 0.45-0.60 lambs per litter for female fertility and from 0.55 to 0.59 lambs per litter for BV male contribution on litter size, with only small differences among models. Results from present study demonstrate that service rams in Romanov sheep have a clearly detectable influence on litter size of their mates. Genetic parameter estimates indicate that direct selection on the service ram effect could increase litter size

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

GI - Šlechtění a plemenářství hospodářských zvířat

OECD FORD obor

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Projekt

<a href="/cs/project/QJ1510139" target="_blank" >QJ1510139: Celostátní informační systém genetického hodnocení hospodářských zvířat</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Small Ruminant Research

ISSN

0921-4488

e-ISSN

—

Svazek periodika

141

Číslo periodika v rámci svazku

August

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

7

Strana od-do

56-62

Kód UT WoS článku

000382274000011

EID výsledku v databázi Scopus

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