Relationship of some metabolic hormones with increased live body weight of male and female of karakul and awassi lambs

الملخص EN

This study was conducted in the animal field of the Al-Kafeel Company fromNovember 2019 till May 2020 to investigate the possible association between growthhormone (GH) and thyroxine (T4) with the growth traits in Awassi and Karakul sheep.

Thetotal number of animals which used in the study was 60 lambs, 28 (13 males and 15females) from Karakul and 32 (18 males and 14 females) from Awassi.

Blood samples werecollected at birth, weaning, and six months of age, and both GH and T4 concentrations weremeasured.

Results showed higher values of T4 for Karakul as compared with Awassi atbirth and weaning.

Karakul breed was also exhibited significantly higher values of GH overAwassi breed only at weaning, while, no significant differences were observed at birth andsix months of age.

Karakul lambs showed higher weights as compared with Awassi lambsat all studied periods.

A highly significant (p < 0.01) positive correlation was observedbetween T4 concentration and the weight of lambs at most studied periods.

Whereas, GHdid not exhibit any correlation with growth traits measured in both breeds.

The elevated T4might be one of the reasons for superiority of Karakul over Awassi breed in live bodyweights.

This high correlation between T4 and growth traits could be used in the earlyselection of lambs to improve the weights of sheep at marketing