PRESERVATION AND THERMOREGULATION PECULIARITIES OF LAMBS OF DIFFERENT TYPES OF BIRTH AND BODY WEIGHT

Abstract

The research was carried out on 1421 lambs of different genders and types of birth (singles, twins and triplets) of the Kharkiv intrabreed type of the Precos breed, as well as the aboriginal Sokolska breed (19 heads). It had lasted for two adjacent years, while ewes were lambing in January-February at the experimental farm of the institute “Hontarivka” in the Kharkiv oblast, the following parameters were measured: the body weight of the lambs (BW), their type of birth (TB) and the character of the hair cover (HC), the age on the mortality date (MA), rectal body temperature (RT), body surface temperature in the chest area (ST), temperature (T) and air humidity (H) and other indicators of the microclimate in the premises. Research has established that the year of birth is an influential factor in relation to (BW) and homogeneity of lambs. The average (BW) of all newborn lambs differed by 6.2% in the compared years for a statistically highly probable difference. There were more than 12% of differences in this trait among single lambs. The indicators of the phenotypic variation of this trait in the herd also differed significantly by year. In general, the level (MA) of lambs in the period from birth to weaning was 6.2-7.9%, and the lambs that died had lower body weight than the average of the sample for the years of evaluation, from 7.7% to 14.2% (р<0.001 in both cases). Although most lambs (from 20 to 38%) died in the first three days after birth, research has not established the probable repeatability of the structure (MA) of lambs in adjacent years, r±mrs=+0.714±0.350 (p>0.5). It is more natural that the total number of lambs that died falls on the first 30 days of their life – 39% (2020) and 57.5% (2021). Studies of changes (ST) during the first hour of life of lambs revealed features related to the type of their birth. Twins and triplets had a relatively greater decrease (ST), namely 3.9 0C (14.2%, p<0.01) in twins and 3.7 0C (13.1%, p<0.001) in triplets, while in singles it was only 1.1 0C (4.1%). The change in body temperature during the first hour of life has a correlation of +0.445 with (BW) of lambs. At the age of 20-25 days, lambs of the Precos breed with a typical merino type of wool cover prevailed in (BW) from 4.3% to 13.7% with an improbable difference and in (ST) 11.6% and 16.7% (p<0.001 in ram lambs and (p<0.01 in ewe lambs) over the peers, who had a wool cover of the “doghair” type. The obtained results of this work are important for the further selection of sheep regarding the increase of body weight at the birth of lambs and the homogeneity of the wool cover.