Acknowledgments References We thank the Koala Preservation Society of New South Wales and F Amell, J Vanner and J White for collection of blood and assessment of health status. Hampson and Partners of Port Macquarie, and Newcastle provided processing and technical assistance in performance of the tests. The work was fmancially supported by Hampson and Partners, the Austra- lian National Parks and Wildlife Service and the Sun Herald Koala Appeal Fund. Backhouse TC and Bolliger A (1961) - Aust J Zool9: 24 Canfield PJ, Brown AS, Kelly WR and Sutton RH (1987) J Comp Path 97: 171 Canfield PJ, O'Neill ME and Smith EF (1989) - Aust Vet J 66: (in press) Dickens RK (1975) - Aust Vet J 51: 459 Dickens RK (1978) Fauna, Postgraduate Foundation in Veterinary Science, University of Sydney, 36: 105 Obendorf DL (1983) J Wildl Dis 19: 123 (Accepted for publication 5 April 1989) An evaluatioIl of calf castration by intra-testicular injection of a lactic acid solutioIl G FORDYCE*, PB HODGEt, NJ BEAMAN*, AR LAING*, C CAMPERO:!: and RK SHEPHERD1 SUMMARY: This experiment evaluated intra-testicular injection 01 a sclerosing drug, lactic acid, for castration of bulls. Its use was compared in 58 Brahman cross calves (50 to 128kg) with the general practice of open surgical castration. Chemical castration appeared to be more palnful than surgical castration, though post-operative swelling and pain appeared similar for both methods. Chemical castration took 3 times longer than surgical castration (58 sec v 20 sec; P<0.01). Scrotal necrosis occurred in 25% of chemically-castrated calves and appeared due to drug leakage from the testes under the high pressure 01 injection. Healing time for chemical castrates was approximately twice that for surgical castrates. Five chemically-castrated calves (18%) retained one testis. Though all 5 were rendered sterile, each maintained androgenesis. This led to secondary male behaviour which caused management problems. Castration method did not influence post-operative growth. It is concluded that lactic acid administration is not a suitable alternative to the open surgical technique for castration of Brahman cross calves. Aust Vet J 66: 272-276 Introduction Most bull calves in Australia are sterilised using the open surgical technique of castration. Its proven advantages are that it is simple, rapid and inexpensive to perform and pro- vides open drainage which limits post-operative infection. The surgical method can be used at any age and allows total abla- tion of both spermatogenic and androgenic tissues. However, this method of castration is of concern to animal welfare organisations. A sclerosing agent recently became commercially avaiable in the USA for intra-testicular injection of calves weighing up to 68kg. The drug** is 88070 lactic acid and,when injected into the testes, is claimed to produced destruction of spermatogenic and hormone-producing cells. The major claims made of the drug are that it is easy to administcr, its use produces no haemorrhage and only minor pain, and there is little chance of post-operative infection, thus is less stressful than other methods of castration. A claim has becn made that 2.5 times the recommended dose could be safely administered. Veterinarians perform a very small proportion of b')vine castrations in this country and if lactic acid were registered for use in Australia it would probably be used under'direction of a veterinarian. Therefore, it would have to offer definite advan- tages compared with the open surgical technique before it would be adopted commercially. • Oueensland Department of Primary Industries, Swan's Lagoon, MiIIaroo, Oueensland 4807 t Oueensland Department of Primary Industries, PO Box 241, Longreach, Oueensland 4730 t Graduate School of Tropical Veterinary Science, James Cook University of North Oueensland, Townsville, Oueensland 4811 , Oueensland Department of Primary Industries, Oonoonba Veterinary Laboratory. PO Box 1085, Townsville, Oueensland 4810 "Chem-Cast®, Bio-Ceutic Laboratories, Inc, Missouri, USA 272 The study reported in this paper compared castration using lactic acid with surgical castration to assess advantages and disadvantages under beef industry conditions. Materials and Metbods Location and Animals The study was carried out at Swan's Lagoon Beef Cattle Research Station (20 0 15'S; l47°14'E) which is located in the dry tropics approximately lOOkm south of Townsville. Holroyd (1985) gave a detailed description of the environment. The V2 to % Brahman crossbred calves used in the study were bred in an extensively-managed breeding herd of 300 cows. Under normal management this continuously-mated herd is mustered 2 to 3 times per year from their 2,OOOha pad- dock, when marking and weaning of calves is carried out. Experimental Method In March 1985, calves were tagged and weighed. Fifty-nine male calves weighing between 50 and 128kg were then ran- domly allocated to either chemical or surgical castration after blocking on weight. The surgical castration method was the same procedure generally used on north Australian beef cattle properties. A No. 22 scalpel blade was used and between castrations was soaked in a chlorhexidine gluconate solutiont. Each testis was held in the distal end of the scrotum while an incision of ap- proximately 3cm in the ventral aspect of the ipsilateral side of the scrotum was made. The testis was then withdrawn. The mediastinum testis and the vas deferens were cut following separation from the testis. Sufficient traction was then placed on the testis to tear the afferent and efferent blood vessels aboye the pampiniform plexus, thus completing the testis removal. t Hibitaine®, Imperial Chemicallndustries Ltd, Melbourne, Australia Australian Veterinary Joumal, Vol. 66, No. 9, September, 1989 I rel SUI eal the th! of jec wi tes tin wa del caí del dis grc Sil! dn me Th thé ret an: cal re,!! Ca!; thE cal ev¡ ml we: (CI COI tes wit in. et blc (Pe Th res; I pri anl usi epi pa: tio- rOl to Stc. fer sat an we tio :j: