Wool production from induced cryptorchids and wethers in a Poll Merino flock.

Abstract

Proc. Aust. Soc. Anim. Prod. (1974) 10; 401 WOOL PRODUCTION FROM INDUCED CRYPTORCHIDS AND WETHERS IN A POLL MERINO FLOCK J.P. EGAN* and D.W. RUSSELL* The practice of inducing cryptorchidism in lambs shortly after birth by forcing the testes up into the body cavity and holding them in that position by means of a rubber ring placed around the top of the scrotum (Hudson et al. 1968) has been demonstrated by a. number of workers to produce liveweight gains superior to those of castrated animals. No information is available, however, on the effect of this operation on wool growth, although several workers have demonstrated that rams cut significantly more greasy wool than their castrated counterparts run under identical conditions (Riches and Johnstone 1949; Dun 1963). Two hundred and twenty Poll Merino ram lambs at Monarto, South Australia, were either castrated or made cryptorchid (by the method described above) at an average age of 4 weeks in May, 1971. The two groups have since been run in the one flock, which is managed as a commercial, all-wether flock. Fleece-free liveweights recorded at weaner (average age 18 weeks), 2-tooth (14 months), and 4-tooth (26 months) shearings showed advantages to the cryptorchids of 6.4$, 11.4% and 13.9% respectively. Greasy fleece weights for the cryptorchids were heavier than those of the wethers by 4.7$, 2.670 and 4.5% at each of these shearings respectively. These results suggest that, in terms of greasy wool production per unit liveweight, the cryptorchids may be less efficient wool producers than the castrates. Fleeces from the composite flock of cryptorchids and wethers at the 2-tooth shearing were traditionally classed in similar proportions into each of the major lines. At 4-tooth shearing, neither analysis of the Australian Wool Realisation Commission (A.W.R.C.) wool types assigned to each fleece, nor crimp frequency measured on three staples from the midside of each, showed any difference in visual quality of the wool from either group. Visual estimates of yield were also similar for both groups, Midside samples were also ta.ken at this latter shearing for determination of clean scoured yield and fibre diameter measurement by the air-flow technique. Results of these analyses are not yet available. REFERENCES DUN, R.B. (1963). Aust. J. exp. Agric. Anim. Husb. 2:262. HUDSON, L.W., GLIMP, H.A., WOOLFOLK, P.G., KEMP, J.DT and REESE, C.M. (1968), J. Anim. Sci. 27:45. RICHES, J.H., and JOHNS-, I.L. (1949). Aust. vet. J. 25:270. I * Department of Agriculture, Adelaide, South Australia. 401