The sucking behaviour of triplet, twin and single lambs at pasture

Abstract

The suckling behaviour of 100 Booroola Merino × Romney and Romney ewes and their lambs was recorded at 1, 3, 6 and 9 weeks post-partum. Lambs were in litters of one, two or three, and records were taken for frequency and duration of sucking over 12 h, intra-litter variation in sucking frequency, initiator and terminator of bouts, and distances between Booroola Merino × Romney ewes and their lambs. Milk production of the ewes was recorded by machine milking at 10, 20, 30, 40, 50 and 60 days post-partum. No breed differences were observed in suckling behaviour. Sucking frequency declined with increasing lamb age, as did duration of sucking. Increasing litter size resulted in an increase in frequency of sucking at all ages, but this was also associated with a decline in duration of sucking. There was, however, a large variation in the proportion of sucking bouts which members of triplet sets missed (14.3–36.9%). The majority of sucking bouts were initiated by the lambs and terminated by ewes. At all ages, single lambs were usually further from their dams than were multiples. The distance between ewes and lambs increased to 6 weeks and declined thereafter. Overall, there was a positive correlation between incidence of sucking behaviours and milk yield, but the effects of milk yield on sucking behaviour could not be partitioned from the influences of age and litter size. The implications of milk availability and the ontogeny of sucking behaviour for the management of ewes rearing large litters is discussed.