Estimation of genetic parameters for body measurements and their association with yearling liveweight in the Makuie sheep breed

Abstract

The main objective of this study was to estimate the genetic parameters for body measurement and yearling live bodyweight traits in the Makuie sheep breed. The data set consisted of 2 144 lambs from 122 sires and 984 dams recorded in 21 years from 1989 to 2009 at the Makuie Sheep Breeding and Raising Station (MSBS). The traits that were studied were height at withers, height at rump, body length, heart girth, leg circumference and yearling weight. The analyses were carried out based on an animal model with the restricted maximum likelihood (REML) approach using a derivate-free (DF) algorithm. Six animal models were fitted, differentiated by including or excluding maternal effects, and with and without covariance between maternal and direct genetic effects. Ignoring the maternal effects, the direct heritability was estimated as 0.20, 0.24, 0.10, 0.14, 0.02 and 0.36 for height at wither, height at rump, body length, heart girth, leg circumference and yearling weight, respectively. The estimates were slightly higher when maternal effects, genetic or environmental, were ignored in the analyses. Using bivariate analysis, the estimates for additive genetic correlations ranged from 0.56 to 0.81 among the studied traits. A log-likelihood ratio test (LRT) was used to select the most appropriate univariate model for each trait. Based on LRT, the direct additive genetic and maternal permanent environmental effects were regarded as an important source of variation of the studied traits. The estimates of genetic parameters can be considered a basis for calculating selection indices for body measurements, as well as revealing their association with yearling bodyweight traits.

Prediction of body weight from linear body measurements in sheep

“…The effect of period of birth might be due to variation in availability of feed and fodder in different periods. The significant effect of period of birth on body measurements was also reported by Tadesse and Gebremariam (2010) in Highland sheep, Petrovic et al (2012) in Merinolandschaf sheep and Jafari and Hashemi (2014) in Makuie sheep.…”

“…The males were having higher values for all body measurements than females. Simliar findings were also reported by Petrovic et al (2012) in Merinolandschaf sheep, Jafari and Hashemi (2014) et al (2016) in Harnali sheep.…”

“…Simliar findings were also reported by Abbasi and Ghafouri-Kesbi (2011) in Makuie sheep and Cilek and Gotoh (2014) in Malya sheep. However, significant effect of dam's age at lambing on body measurements was reported by Jafari and Hashemi (2014) in Makuie sheep.…”

Efecto de la raza paterna en características de la canal de corderos para carne en Hidalgo, México

“…This agrees with results of other researchers (25) , who indicated that single-born lambs had longer leg since they are born, an advantage that remains until they reach adult age (26) . These same authors found that the type of birth affects the leg circumference, because Makuie Iranian lambs had higher values of this parameter (P0.05) in single-born lambs than in twins and triples.…”

“…Regarding the effect of sex, Tables 3 and 4 show that males outperformed females (P0.05) in the weight and percentage of the shoulder and anterior-loin, but females had higher a edades adultas (26) . Estos mismos autores encontraron que la circunferencia de la pierna también puede ser afectada por el tipo de nacimiento, pues ya que corderos de la raza iraní Makuie, tuvieron valores más altos de este parámetro (P0.05) en corderos de parto sencillo que en los de parto doble y triple.…”