Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. I6 CONSUMER APPRECIATION OF MEAT FROM LAMBS GROWN ON GRAIN DIETS CONTAINING LUPINS J.R. CURRIE*, L.P. THATCHER* and G.M. GAUNT* When feed may be lotfed (G.B. Roberts people for the pasture. is scarce in N.E. Victoria, lambs on farms where lupins are grown on grain diets containing lupins. Preliminary consumer work and P.A. Kenney, unpublished data) indicated a preference by some meat from these lotfed lambs to that from lambs raised at Results of consumer panel work investigating this preference by some people are reported in this paper. Lambs were grown from weaning at 6 weeks of age for 15 weeks on a grain diet (90% lupins, 6% barley, 4% mineral mix) or raised at pasture and slaughtered at about 40 kg liveweight. Samples (1 x 1 x 2 cm3) of lean meat from the M. longissimus dorsi and M. semimembranosis of lambs from the two diets were cooked in a microwave oven and presented to consumers. They were asked to rank the two samples in order of preference. In a rural centre 28.7 % of 108 respondents and in Melbou rne 64.8% of 71 respondents expressed a pref eren ce for the grain -fe d lamb. Rural and city consumers apparently have different taste preferences for lamb. A specialist market for lambs grown on grain diets containing lupins could be developed if suitable product description systems for meat were in existence. *Rutherglen Research Institute, Dept Agriculture and Rural Affairs, Vic. 3685 GROWTH AND SEXUAL MATURATION IN MALE SHEEP RECEIVING ANABOLIC STEROIDS M.J. D'OCCHIO*, C. PAPACHRISTOFOROU*, R. JAMES** and B. P. SETCHELL* Entire rams (R) show better feed conversion efficiencies and produce heavier and leaner carcasses compared with wethers (WI; however, behavioural and fertility considerations of rams offset their superior performance as meat producing animals. Suppression of pubertal development in rams might be achieved through use of anabolic compounds which influence the secretion of reproductive hormones. The present study therefore examined growth and sexual maturation in rams and wethers implanted with Revalor R (trenbolone acetate + oestradiol-176). Treatment groups included R(n=9); R + Revalor(RI,n=7); Revalor ear implants were administered at 4 W(n=9>; W + Revalor(WI,n=8). weeks of age and again at 14, 28 and 37 weeks. Weight gains (kg/lamb) from 1 to 6 months were lower (P < 0.05) in W(23.5) than in R(25.61, RI(26.2) and wI(26.7). Testis diameters at 6 and 12 months were smaller (P < 0.01) in RI(21 and 25 mm, respectively) compared with R(47 and 56 mm>. At 9 months, seven rams produced ejaculates containing motile sperm whilst no sperm were observed in ejaculates of RI. Serum luteinizing hormone levels (ng/ml) ranged from 0.2-0.3 in RI and WI, O-4-2.8 in rams and 5.2-13.0 in wethers. These data indicate that Revalor implants effectively retard pubertal development in rams by suppressing gonadotrophin secretion and maintain growth performances in RI and WI characteristic of rams. Revalor implants have potential as an alternative to surgical gonadectomy of meat producing animals. *Department of Animal Sciences, Waite Agricultural Research Institute, University of Adelaide, Glen Osmond, South Australia 5064. **Hoechst Australia Ltd. P.O. Box 4300, Victoria 3001. 407