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An analysis of lambing ewes three times in two years in Southland

Allan, W. D.
Fields of Research
ANZSRC::070206 Animal Reproduction
This study examines the management and profitability of three lambings in two years under Southland conditions, and how they compare with those of a conventional Southland farming system. There has been little work done world wide but what overseas literature there is suggests that lambing ewes three times in two years (ie. a sustained 8 monthly lambing interval) is possible. It does however require the seasonal breeding nature of the ewe to be altered either by cross-breeding, selection, use of the 'ram effect', exogenous hormones or a combination of the above. There has been no work done in New Zealand on three lambings in two years, so overseas information and New Zealand data on autumn lambing has been used in this study. To analyse the conventional and three lambings in two years farming systems, a feed profile model has been used to determine stock numbers carried and lamb production under each of the conception and feeding regimes studied. Feasibility of each system is dependant on average pasture cover remaining above the minimum required pasture cover (to achieve desire intakes) at all times. Results from feed profiling showed that the winter and early spring is the critical feeding period, thus determining the stocking rate. The conventional system wintered 19.4 SU/ha under all grass and hay wintering. However the use of a high yielding winter feed crop was necessary to maintain a stocking rate of 13.6 SU/ha through winter for a multiple lambing system. For the prices received in the 1988/89 year, the financial result is that there is a lower return for three lambings in two years than for a high producing conventional Southland farm ($76 000 vs $92 000 cash farm surplus). Thus there are no financial benefits to the farmer to compensate for the additional risk, and labour and management requirements associated with such a system. Even with price conditions which favour the multiple lambing system (ie lower wool prices and higher prices for lambs sold in winter) the return is only slightly above that of the traditional farms - A return that is too low to warrant lambing ewes three times in two years in Southland.