SUCCESSFUL FOSTERING OF ORPHAN LAMBS BY NONPREGNANT EWES INDUCED TO LACTATE USING EXOGENOUS HORMONE-TREATMENT

Six nonpregnant ewes were induced to lactate by an exogenous hormone t reatment lasting 6 weeks. At the end of the treatment one alien lamb w as adopted by each ewe. Each ewe was initially indifferent to the alie n lamb and required only mild restraint to allow the lambs to suck suc cessfully. Maternal interest subsequently increased and strong ewe-lam b bonding was evident by 80 minutes (n=1), 10 hours (n=4) or 24 hours (n=1) in different cases. The lambs required supplementary milk for 4- 6 days while milk production by the ewes increased to adequate levels. Thereafter they were reared entirely by the ewes. Another four nonpre gnant ewes were induced to lactate by a similar hormone treatment and were then hand-milked thrice daily for 23 weeks. One alien lamb was th en introduced to each ewe. All four ewes were aggressive towards the l ambs which were removed after 10-30 minutes. The ewes were then inject ed subcutaneously with 5 mg of oestradiol-17beta and were placed in fo stering stocks. After a further 3-5 hours the lambs were re-introduced . Strong ewe-lamb bonding occurred during the subsequent 10 hours in a ll cases. All 10 lambs were reared successfully by these ewes until at least 3 months of age, when observations stopped. It was concluded fi rstly that nonpregnant ewes induced to lactate artificially will adopt and rear orphan lambs successfully, provided that additional milk is given to meet shortfalls during the first 4-6 days; and secondly that a 5 mg injection of oestradiol-17beta may facilitate fostering of lamb s by ewes in established lactation whether the lactation is induced ar tificially or not.