Chemical shearing : effects in field trials of repeated doses of cyclophosphamide on pregnancy, wool growth and CPA tolerance.

Abstract

Proc. Aust. Soc. Anim. Prod. (1978) 12: 272 CHEMICAL SHEARING : EFFECTS IN FIELD TRIALS OF REPEATED DOSES OF CYCLOPHOSPHAMIDE ON PREGNANCY, WOOL GROWTH AND CPA TOLERANCE A.C. SCHLINK* and W.V. MACFARLANE* __ The anti-cancer drug, cyclophosphamide (CPA) has been proposed as a chemical defleecing agent for wool harvesting. The CPA is highly toxic and a long-term study was undertaken to evaluate its effects in a breeding flock of Merino ewes. Four groups of 5 were given.15, 20, 25 and 30 mg orally in -the last trimester of pregnancy in 1973. conventionally shorn. The treatments were repeated and 1976 the groups on 15 and 20 mg of CPA/kg were CPA/kg respectively. The lambs produced each year treatment as their dams. of CPA /kg body weight A control grolip'was in 1974 but in 1975 given 30 and 25 mg of received the same CPA Doses of 15 and 20 mg of CPA/kg did not remove wool from all the ewes in the, second year and they failed also to remove wool from the ewes' offspring on their first exposure to CPA. The 25 and 30 mg of CPA/kg dose rates in the las,t trimester of pregnancy were effective in all 4 annual defleecings, with no measurable long-term effects on the ewes, either in wool production (Table l), or on the lambs they reared. Rugs were used from the time of drug administration to prevent the loss of wool in the field. Since the sheep were not housed at any stage of the investigation, rugging was required. a'fter CPA defleecingc to prevent losses from exposure to the early winter conditions. In the 4 years of CPA defleecing, 2 deaths were attributed to adverse weather conditions. The chemical defleecing of s,heep was shown to be possible with CPA in. small flocks of sheep with limited supervision of the animals. No decrement in fecundity, lamb growth or' wool yield was detected in these groups. Lambs from the CPA-treated ewes had growth rates similar to those of the control group. The lambs born were maintained in the experimental flock and the wool production of the CPA-treated offspring did not vary from that of the control group. A second generation of sheep was apparently unaf.fected by the CPA treatment. ROUGEOT, J. and THEBAULT, R-G. (1975). France; INRA and ITOYIC, 352-360. Tome II: Espece ovine, Paris, - * Department of Animal Physiology, Waite Agricultural @search Iristitute, Glen Osmond. S.A. 5064. 272.