Influence of non-genetic factors on the maternal ability of Santa Inês ewes

Tatiana Saraiva Torres,Alan Oliveira Do Ó,Luciano Silva Sena,Gleyson Vieira Dos Santos,José Lindenberg Rocha Sarmento,Artur Oliveira Rocha

doi:10.1590/0103-8478cr20200580

Abstract

ABSTRACT: The aim of this study was to evaluate the influence of different non-genetic effects on indicator traits for maternal ability in Santa Inês ewes. Data included performance records of 100 lambs (males and females) born from 59 dams, from 2009 to 2012. The analyzed traits were birth weight (BW), weaning weight (WW), average daily gain from birth until weaning (ADGBW), total litter weight at birth (TLWB), and total litter weight at weaning (TLWW). The effects analyzed were the year of birth of the lamb, birth season, dam age at lambing, dam weight at lambing, sex of the lamb, lamb birth type, interaction between sex and birth type, and interaction between sex and birth season. SAS® software (SAS University Edition, USA) was used for calculation of the analysis of variance, means, and Pearson correlation coefficients. With the exception of the birth season, all the other environmental effects evaluated had a significant influence on at least one of the studied traits. The correlation estimates ranged from low to high and were either positive or negative. Birth weight was negatively correlated with the birth type and influenced positively all the other performance traits evaluated. The maternal ability of Santa Inês ewes was more clearly influenced by the age and weight of the dam at lambing, and the lamb birth type.

Highlights

IntroductionIn Brazil, the sheep flock is composed of almost 18 million animals, of which 64.0% are concentrated in the Northeast region (IBGE, 2018)
Sheep farming is responsible for 4.6% of the world’s meat production (FAO, 2019)
The average value of birth weight (BW) in the present study is within the range of 3 to 4 kg found by COSTA et al (2012), KORITIAKI et al (2013), SUPAKORN et al (2013), and PERUZZI et al (2015)

Summary

Introduction

In Brazil, the sheep flock is composed of almost 18 million animals, of which 64.0% are concentrated in the Northeast region (IBGE, 2018). In this region, most of the ovine flocks are composed of woolless sheep. Most of the ovine flocks are composed of woolless sheep These animals are well-adapted to tropical climate conditions and are able to express their production potential in harsh environments (MCMANUS et al, 2010). Sheep growth from birth until weaning is determined by the genes of the animal, the maternal genetic composition, the environment where the lamb is reared, and the environment provided by the dam, that is, maternal care and milk supply (SARMENTO et al, 2011; DWYER, 2014). It is relevant to measure which environmental effects (i.e., non-genetic factors)

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Conclusion