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Factors affecting gestation length in goats and the effect of gestation period on kid survival
Published online by Cambridge University Press: 01 August 2000
Abstract
Data on 1468 pregnancies and 2356 newborn goat kids of six genetic groups under intensive management were utilized to determine some genetic and non-genetic factors affecting gestation length, and to assess the relationship between gestation length and survival of kids to 25 days of age. The study revealed significant (P < 0·01) effect of breed of dam, litter weight, breeding season and parity on gestation length. Number of kids born and sex of kids were not a significant source of variation affecting this trait. Granadina goats had the shortest gestation (149·0±0·31 days), whereas Toggenburg (151·7±0·28 days) and Alpine (151·4±0·46 days) had the longest. Litter weight and gestation period were related curvilinearly in summer and linearly in autumn. Gestation of goats bred in summer was 1 day longer (P < 0·01) than those mated in the autumn. There was a progressive reduction of gestation length as parity increased (151·3±0·24, 150·6±0·17 and 149·9±0·39 days for 1, 2·6 and > 7 kiddings, respectively). The mean survival rate of kids gestated < 148 days and 148–;152 days were 78±2 and 87±1, respectively, and these were significantly lower (P < 0·05) than the survival rate of kids gestated 152–156 days and > 156 days (94±1 and 95±2). In conclusion, prolonged gestation (152–160 days) in goats was beneficial because it resulted in heavier litters at birth and higher viability of neonatal kids.
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- © 2000 Cambridge University Press
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