Livestock Studies 1978, Vol 18, Num, 3-4     (Pages: 064-077)

Studies on the improvement of twinning rate with the use of hormones in Karakul sheep

Hilmi KÖSEOĞLU

- A study on the effect of pregnant mare serum (PMS) for increasing the litter-size of Karakul Sheep At Çifteler State Farm. This study has been carried out on the Karakul ewes in order to increase the rate of multiple births by using PMS.

40 Karakul ewes (2.5 years old) were divided into two groups as an experimental and control in the years 1968 and 1969. 500 I.U. PMS was injected daily to each experimental ewes in the days of 13 – 14th., 15 th. And 14 th. – 15 th.-16 th. During the oestrous cycle in 1968-69 respectively. Equal number of experimental and control ewes were inseminated with fresh semen from the same rams and also were kept under the same environmental conditions.

The conception rates were 85 %, 70 % for treated ewes and 95 %, 85 % for controls in 1968-69 respectively. All pregnant ewes lambed in both groups. The differences between groups were significant (P<0.01). PMS didn`t effect on the conception and parturition rates.

The percentage of single, twins and triplets (based on lambed ewes) were 58.8 %, 35.3 %, 5.9 % for treated and 100 %, 0.0 %, 0.0 % for control ewes respectively in 1968. 42.8 %, 42.8 %, 14.3 % for treated and 82.3 %, 17.6 %, 0.0 % for control ewes respectively in 1969. All differences between the groups were statistically significant (P<0.05-0.01). PMS treatmenthas increased the litter sizes.

The lambing percentages were 125 %, 120 % for experimental groups and 95 %, 100 % for control groups in two years respectively. The number of lambs dropped per ewe were 1.47, 1.71 for experimentals and 1.0, 1.18 for controls in 1968 – 69 respectively. All differences were also significant (P<0.05-0.01).PMS treatment has increased the lambing percentage and also the number of dropped lambs per ewe. Keywords :