Fostering in sheep: experiences with the use of neatsfoot oil

Abstract

This paper reports the results of 3 studies on variables associated with the use of neatsfoot oil for substitutive or additive fostering of lambs. In the first study, neatsfoot oil was applied at the rate of 60 mL/kg of liveweight to 3-day-old lambs from Merino and Border Leicester x Merino ewes, and the lambs were exchanged between pairs of ewes of the same breed 3.5, 7 or 24 h later. The proportion of ewes accepting the alien lamb from the other ewe of the pair within 17 h generally increased with the period from application to exchange. Crossbred ewes accepted the foster lambs more readily than did the Merinos. Acceptance rates with batches of neatsfoot oil produced by different methods were similar. We found no advantage in smearing the ewe's nose with neatsfoot oil at the time the oil was applied to the lamb. Additive fostering in 20 ewes that accepted the alien lambs and were left with their own lambs was 95% successful and appeared permanent. In the second study using similar methods, with lambs of 28 crossbred ewes anointed 24 h prior to exchange, no advantage was found in presenting the foster lamb to the ewe at night over presentation during the day. Most foster lambs were accepted within 12 h, and all ewes reaccepted their own lambs after a 13 h absence. The acceptance rate of foster lambs by the crossbred ewes ranged from 70 to 83%. In the third study, 27 Merino ewes whose lambs were anointed with neatsfoot oil 7-40 h after birth, were presented with freshly anointed foster lambs 24 h later. The rate of acceptance of the foster lambs within the next 24 h was 74%,but many ewes required prolonged restraint before reaccepting their own lambs after 5-26 h separation. The results show that most ewes can be induced to accept foster lambs 1-2 days post partum, if their offspring have been liberally coated with neatsfoot oil for 24 h, and then substituted with neatsfoot-treated foster lambs. For additive fostering, the ewes' offspring should be returned within a few hours.