Document Type : Original Article
Authors
1
Animal Production Research Institute, Agriculture Research Center, Ministry of Agriculture, Dokki, Giza, Egypt.
2
Department of Physiology and Biochemistry, Faculty of Veterinary Medicine, Kafr EI.Sheik, Tanta University, Egypt
3
Public Authority for Agriculture Affairs and Fish Resources - State of Kuwait
Abstract
A total of 56 imported Chios ewes were bred with Naeemi rams in three mating
seasons (summer. winter. autumn). to study the reproductive performance under
Kuwait s hot and arid environmental conditions. In each mating season, ewes were
joined with rams in the ratio of one ram to 18-20 ewes. The number of lambs born,
lambs weaned, birth weight and weaning weight were recorded for each ewe,
Lambing and weaning data were used to calculate ewes lambing per ewes joined
(fertility), lambs born per ewes lambed (prolificacy), lambs born per ewe joined
(lambing rate) and lambs weaned per ewes lambing (weaning rate). The overall
means of fertility. prolificacy, lambing rate and weaning rate were 54.76, 219.57,
120.24 and 68.57%. respectively.
Autumn mating season produced the best values of reproductive performance
among the three breeding seasons. Chios ewes showed the higher (p < 0.01) fertility
(63.79%), lambing rate (139.66%), and weaning rate (100%) in autumn season. While
in summer mating season. the ewes had higher (P<O.OI) prolificacy (225%) and
multiple births (78.57%). In summer mating season, 14 ewes were examined for
ovulation rate (OR) by endoscopy. Litter size (LS) was recorded and ova wastage
(O'N) was calculated. The overall means of OR, LS and OW were 2.93, 1.86 and
1.07, respectively. The overall means of birth weight and weaning weight were 3.61
and 19.38 kg, respectively with no significant seasonal difference at birth weight.
There was a significant (P<O.OI) effect of litter size on the birth and weaning weight.
Single lambs were Significantly (P<O.OI) heavier at weaning (22.65 Kg) than twin and
triplet lambs (19.15 and 16.31 kg, respectively). There was a distinct seasonal effect,
with heavier weaning weights (22.61 kg) occurring in summer-born lambs and lighter
weight (17.92 kg) in autumn-born lambs. In conclusion, the results of this study
illustrate the potentiality of Chios as a prolific sheep breed (>2.0 lamb/ewe lambed)
under intensive lamb production in Kuwait hot arid condition. The results also indicate
that autumn mating season was the best in almost all traits studied.
Keywords
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