Reduction of age at sale for export carcasses : will it affect beef producers in tropical regions?

Abstract

Proc. Aust. Soc. Anim. Prod. Vol. 16 REDUCTION AGE AT SALE FOR EXPORT CARCASSES: WILL IT BEEF PRODUCERS IN TROPICAL REGIONS? W.J. TAYLOR* and T.H. RUDDER** SUMMARY AFFECT Increasing live weight at sale from 550 to 700 kg from 5.5 to 2.5 years had a marked effect on income. increased the drought susceptibility of the herd because the herd were lactating cows and yearlings. Increments increased weaning rates were greatest at high sale weights and reducing sale age Decreasing sale age higher proportions of in gross income from and low sale ages. (Keywords: beef herd simulation, sale age, live weight.) INTRODUCTION Beef produced in Queensland often comes from breeding and fattening enterprises producing carcasses between 250 and 375 kg. At sale steers range from 2.5 to 5.5 years of age depending on location, soil fertility, stage of property development and seasonal conditions. Until recently there was no incentives to reduce age at sale because export processors paid higher prices for heavier carcasses with acceptable fat cover Now there are indications that reducing age at sale will irrespective of age. improve prices. However, any change to age at sale will focus attention on a number of secondary effects, such as live weight at sale, the relative importance of reproductive and survival rates and drought susceptibility of the herd. These effects may have more influence on income than the primary reason for change and should be estimated before altering an established managerial system, Some effects of reducing age at sale in a breeding and fattening herd are examined in this paper. METHODOLOGY A series of computer models was constructed to simulate herd structure and gross income under different levels of production, and the logic of which can be inferred from Taylor et al. (1980). Biological and managerial variables held constant for all models were: (i) herd size at 2500 mixed age cattle because standard adult equivalent factors were thought to be inappropriate over the range of live weight for age and weaning rates studied, (ii) age at first (2 years) and final (10 years) joining, (iii) (iv) breeder proportion of bulls (4 %) and their live weight at sale (650 kg), mortality rates (3 to 6 % depending on age and lactation status), (v) growing cattle mortality rates (2 to 5 % depending on age), (vi) culling for reproductive failure was confined to non-lactating cows and (vii) cast for age cows were fattened after weaning their final calf and sold at a live weight of 400 kg. Weaning rates and age at sale var ied (50, respectively ) for both steers years, 65 and 80 % and 2.5, 3.5, 4.5 and and cull heifers. Live weights 5.5 at * Queens1 and Department of Primary Industries, PO Box 689 Rockhampton, Qld 4701. ** Queens1 and Department of Primary Industries, GPO Box 46 Brisbane, Ql d 4001. 379 Proc. Aust. Soc. Anim. Prod. Vol. 16 sale were varied from 550 to 700 kg for steers and from 355 to 490 kg for cull heifers. A live weight at sale of 550 kg for steers is achieved over many locations at the sale ages examined while the 700 kg represents the probable genetic potential. The prices for steers, cull heifers, cast for age cows and bulls were inferred from current Rockhampton reports (Mayqune 1985) and were 95, 85, 78, 100 cents per kg live weight, respectively. RESULTS AND DISCUSSION Relationship between drought risk and sale age . Table 1 The percentage of high drought risk animals in the herd at different weaning rates and sale ages Pregnant and lactating cows and growing cattle from 6 to 15 months of age are drought susceptible groups. The proportion of high risk cows ranges from 19 to 30 % as sale age decreases from 5.5 to 2.5 years and weaning rates increase The comparable trend for yearling cattle is an from 50 to 80 % (Table I). increase from 18 to 30 %. In a herd of 2500 mixed cattle these increases represent an extra 275 lactating cows and 300 yearling cattle. The proportion of drought susceptible animals in a herd is economically important to management. In Queensland the frequency of droughts of greater than six months, varies from one each five to six years in the <380 mm to one each seven to eight years in the > 760 mm annual rainfall areas (Alexander 1966). The effect of drought on mortality is higher in extensively managed herds which are usually located in low rainfall areas. In these areas drought mitigation Thus costs are exacerbated by high feed, transport and distribution costs. changes to existing production systems should be interpreted against the risks and costs of drought. Relationship between weaning rates and sale age Fig.1. shows the effect on gross income at four sale ages , four sets of live weights at sale and two weaning rates. In all cases the effect of the 65 % weaning rate was median to those of the 50 and 80 % . The effect on gross income of increasing weaning rate from 50 to 80 % varied from 0 % at 5.5 years and 550 kg live weight to 18 % at 2.5 years at 550 kg live weight at sale. The comparable figures for 700 kg live weight at sale were 3 % and 22 % in logical sequence. This indicates there is little incentive to increase weaning rates unless age at By contrast, an increase in live weight sale can be reduced below ~3.5 years. at sale of steers from 550 to 700 kg and cull heifers from 385 to 490 kg increases gross income from 19 to 24 % across the range of weaning rates, Increasing live weight is economically and irrespective of age at sale. managerially easier to achieve than increasing reproductive rates because returns to investment are received more quickly and less animals are involved. 380 Proc. Aust. Soc. Anim. Prod. Vol. I6 381 Proc. Aust. Soc. Anim. Prod. Vol. I6 Relationship between age and live weight at sale Fig.1. also shows the relationship between age and live weight at sale on gross income. Increasing growth rate so that target live weights can be achieved at younger ages increased gross income by 16, 22 and 25 % at 50, 65 and 80 % weaning rates, respectively, for each year reduction in sale age. The figure also demonstrates the effects on gross income of increasing both age and live weight at sale. As sale age increases the live weight increment required to equate gross income across various sale ages is reduced. For example, similar gross income can be generated by selling at 2.5 years and 550 kg and selling at whereas selling at 4.5 years and 550 kg produces similar gross 3.5 and 700 kg, income to selling at 5.5 years and 650 kg. COMMERCIAL IMPLICATIONS High cost development such as improved pasture, cropping, irrigation is prerequisite to significantly higher growth and reproductive rates for many herds in central and northern Queensland. Therefore, changes should be planned with regard to investment and managerial contraints. In the absence of market pressures to reduce age at sale the first logical step could be to increase live weight at sale towards the higher levels examined if they are not already being achieved. This approach will give a similar increase in gross income as each years reduction in age at sale at a given weight, and greater increase than by increasing reproductive rates especially at the lower sale live weights. Increasing live weight at sale is financially and managerially easier to effect because there is a smaller number of animals involved when compared with either of the other two strategies. During the stage of increased to maintain total implement drought mitigation with increases in numbers of reducing age at sale, breeder numbers need to be herd numbers. Concurrently, it is necessary to practices to cope with the higher risk associated drought susceptible cattle. When maximum live weight and minimum sale age are obtained, emphasis should be placed on improving weaning rates to increase gross income, because returns to increased weaning rates are low until high live weight at sale and younger sale In better environments, reproductive rates of more than 75 % ages are achieved. can be achieved with minimum managerial and financial inputs, however this is not the case in harsher environments in tropical regions. If the premiums paid for younger 250 to 375 kg carcasses become cattle bred in the harsh regions may be sent to the more favoured for finishing at younger ages. In turn, this would put pressure research to develop commercially viable technology to ensure high and survival rates in breeding herds in harsher environments. REFERENCES TAYLOR, W.J., 13: 365. substantial, environments on industry reproductive RUDDER, T.H., and NEAL, J.A. (1980) Proc. Aust. Soc. Anim. Prod. Report of the ALEXANDER, G.I. (1966) Drought Problems in Queensland. Representative Committee on Drought Problems. QDPI, Brisbane. 382