Studies on the attainment of puberty in karadi ewe lambs : 1. Effect of level of protein on age and weight at puberty

الملخص EN

Thirty Karadi ewe lambs ,6 months old were divided randomly into two groups and allocated into two dietary protein levels namely 12% (n=15;initial weight =25.40±1.01kg) and 16 %(n=13;initial weight =26.54±1.65kg).

Two rams equipped with marking crayons were introduced for each group to facilitate estrus detection .Animals were weighed at weekly intervals.

Also, blood samples were collected at the onset of estrus for progesterone determination.

Two ewe lambs from second group was died during the trail .Results revealed that: age and body weight at puberty averaged 235.78±7.40 days and 35.46± 1.16 kg, respectively.

Both traits were not affected significantly by protein level being used, whereas month of lambing had a significant effect on age at puberty, but not on body weight .Yet ewe lambs born in March were younger than those born in December, January and February.

All the correlations between each of age and body weight at puberty and each of gain from birth –puberty, weaning –puberty and six month weight –puberty are positive and significant and ranged between 0.510 and 0.990.

Also, from regression analysis it seems that ewe lambs which grew faster during post –weaning tended to reach puberty at an earlier age and at heavier weight.