Effect of Some Environmental Factors and Inbreeding on Some of Growth Traits of Saidi Lambs.

Abstract

In the present study data were collected from Seds experimental station of Animal Production, Ministry of Agriculture, during the years from 1995 to 2006 on local Saidi sheep. A total number of 1644 Saidi lambs records were available for this study. The data were analyzed by the method of Least-Square analysis. The study aimed to determine the effects of some environmental factors ( lambing season, lambing year, sex of lamb and type of birth ) and inbreeding on the weights of lambs at birth, monthly weight until 18 month and average daily gain in body weight at different periods of age, Bw-3, ˃3-6, ˃6-9, ˃9-12, ˃12-15 and ˃15-18 months. All weights at different age significantly affected (P<0.001) by the environmental factors except weights at the periods of 12, 16, 17 and 18th for lambing season and at 15, 16 and 18 months for type of birth. The inbreeding did not had significant effect on body weights at different periods of age except the weight at one and two months of age were significant (P< 0.001). The average daily gain in body weight of Saidi lambs at all different periods of age were significantly affected (P<0.001) by lambing season, lambing year and sex of lamb except at the period of ˃12-15 months for lambing season were not significant. Results indicated that only the average daily gain in body weight at the periods of ˃Bw-3 and ˃3-6 months were influenced (P<0.001) by type of birth. The average daily gain at the period from birth to 3 months affected significantly by inbreeding (P<0.037). Therefore the non-genetic factors must be considered in evaluating growth performance in the case of increase the economic gain to avoid the breeding effect.

Effect of non-genetic factors on growth performance in Sohagi sheep

“…For instance, Yilmaz et al (2005) reported that male lambs had a higher ADG than their female counterparts. These findings are consistent with those of other scientists as the study by Farrag et al (2018) reported that male Saidi lambs outperformed females in terms of average daily gain. Birth type revealed a significant influence (P<0.01) on ADG1, while there was no significant distinction on ADG2 or ADG3.…”

“…The influence of birth season could be due to the better environmental conditions from February to May especially the availability of Egyptian clover. These results agree with those established in the literature for Hassan and El-Feel (1988), Oudah (2002), Yilmaz et al (2005, Abbas et al ( 2010), Farrag et al (2018) and Elaref et al (2020). The parity of ewes significantly affected ADG3 (P<0.01) but had no significant impact on ADG1 or ADG2.…”

“…The significant difference in the average daily gain of sohagi lambs is attributed to differences in the subsequent management and environmental conditions. According to Farrag et al, (2018), the year of pregnancy significantly affects the growth performance of Saidi lambs from birth to 18 months of age. Similarly, Odeh., (2002) found that the year of pregnancy has impact on the average daily gain of Rahmani sheep.…”