During 1993-95, post parturient behaviour was studied in 370 Merino ewes, 2-6 years of age, from 2 lines divergently selected for multiple rearing ability kept at the Elsenburg Development Institute. Since 1986, high line ram and ewe replacements had been selected from dams that reared >1 lamb per mating, based on performance after 2 lambings. Progeny of ewes that reared fewer than 1 lamb per mating were selected for the low line. Permanent separation of the ewe from her lamb(s) was recorded in a higher proportion of primiparous ewes compared with multiparous ewes (0.144 and 0.073 respectively; P = 0.06) and in a higher proportion of ewes caring for multiple lambs compared with those caring for singles (0.147 and 0.034 respectively; P = 0.01). Ewes caring for multiple lambs remained at their parturition sites for longer periods than ewes caring for singles (7.81+or-0.49 and 6.66+or-0.38 h respectively; P = 0.05). The proportion of ewes separated from one or more lamb(s) was similar in the high and low lines (0.090 and 0.096). The proportion of primiparous high line ewes caring for a viable single lamb and getting separated from it was lower (P = 0.075) than in low line contemporaries (0.023 and 0.143). A similar trend was recorded in primiparous high line ewes caring for multiple lambs (0.292 and 1.000 respectively; P = 0.111). Interference with or by other ewes was more likely to result in separation of one or more lamb(s) in high line ewes than in low line ewes (0.500 and 0.167; P = 0.074).
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Elsenburg Agricultural Development Institute, Private Bag X1, Elsenburg 7607, South Africa.|
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