Influence of Maternal Age and Number of Fetuses (Single or Twins) on the Gestation Length of Ile-de-France Sheep
2019
Nikola Metodiev
The aim of this study was to evaluate the factors maternal age and number of fetuses (single or twin) on the gestation length of Ile-de-France sheep. The study was carried out with pure bred Ile de France ewes from the breeding flock that was raised in experimental base (EB) of Institute of Animal Science (IAS) ndash%253B Kostinbrod, Bulgaria. The study covered 830 records of ewes for the period 2008-2018. The ewes were at age between 2 to 8 years and gave birth to singles (n %253D 408) or twins (n %253D 422). The age distribution of ewes was as followed%253A 2 years of age%253A n %253D 65%253B 3 years of age%253A n %253D 133%253B 4 years of age%253A n %253D 169%253B 5 years of age%253A n %253D 147%253B 6 years of age%253A n %253D 137%253B 7 years of age%253A n %253D 105%253B 8 years of age%253A n %253D 74. The age of ewes was influenced significantly on the length of gestation (Рle%253B0.01), whereas the number of fetuses and the interaction between the effects of age of ewes and number of fetuses did not. The average length of gestation for all cases was 150.59 days. It was observed a shorter duration of pregnancy in ewes at two years of age, compared to older sheep, as the differences were significant between 2 years of age and%253A 6 years of age (Ple%253B0.01), 7 years of age (Ple%253B0.01) and 8 years of age (Ple%253B0.05). 3%252F4 or 77.21%25 of all pregnancies were between 149 and 153 days, with the largest share being at days 150 (18.55%25) and 151 (18.19%25).
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