Phenotypic characteristics of breeding traits in Ile de France sheep

Staika Laleva, Petya Slavova, Tania Ivanova, Georgi Kalaydzhiev, Yovka Popova, Nikolai Ivanov, Nikola Metodiev

Abstract: The aim of the study is to analyze the phenotypic characteristics of breeding traits in sheep from two Ile de France flocks. Object of the research are 222 female animals bred in AI–Stara Zagora and 200 in IAS–Kostinbrod for the period 2011–2015. The following main breeding traits have been monitored: live weight at birth up to 2.5 years and fertility /number of lambs born per ewe/ within the whole study period, by the sequence of lambing. The intensity of growth over three ages was examined. The statistical data processing is performed using the software product SYSTAT 13, as the general statistical working model looks as follows: Yij = μ + аi + eij, where: Yij – observation of each corresponding trait; μ – the total average for the trait; ai – fixed effect of the i-th flock–year–season; eij – random effect of the unobserved factor.
As a result, the following conclusions can be drawn: The Ile de France sheep reared in the Agricultural
Institute – Stara Zagora and the Institute of Animal Science – Kostinrod have high productivity.
The live weight of the female animals involved in the breeding process supposes a very good physiological
status and ability to perform their genetic potential for high productivity. The average daily
gain of lambs is found to be the highest during the period from birth to 10th day – 376 g for the flock
of ZI–Stara Zagora and 346 g for the flock of IAS–Kostinbrod, after which it slightly decreases. The
average fertility is in the range of 1.573 to 1.717 lambs per ewe. It reaches its maximum at the third
lambing for the animals reared in the Agricultural Institute – Stara Zagora and at the fourth in IAS –
Kostinbrod, and after that reports a decline.

Keywords: breeding traits; Ile de France; sheep; рhenotypic characteristics

Date published: 2020-10-09