Effect of ewe milk production on profitability of dryland lamb production systems

Abstract

A farmlet study was carried out over 2 years to examine the role of milk production in dryland lamb production systems. Poll Dorset ewes (high milk producers) were mated with Romney rams and Romney ewes (average milk producers) were mated with Poll Dorset rams to produce lambs of a similar genotype. As well as two levels of milk production, two fecundity treatments were used and farmlets were replicated. Farmlets were 2.9 ha and stocked at a rate of 15 ewes/ha. Farmlets were managed to ensure similar pasture covers at the start of winter and at lambing. Poll Dorset ewes produced more milk and in both years their twin lambs had a small but significant advantage in lamb growth rate. This resulted in earlier drafting of lambs and the ability to obtain early season premiums. In the low fecundity farmlets, net financial returns for Romney and Poll Dorset ewes were $605/ha and $676/ha (+ 12%) in Year 1 and $709/ ha and $762/ha (+ 7%) in Year 2. For the high fecundity farmlets, financial returns for Romney and Poll Dorset ewes were $637/ha and $818/ha (+ 28%) in Year 1 and $866/ha and $921/ha (+ 6%) in Year 2. The greatest financial benefits to increased milk production were achieved in high fecundity ewes in Year 1 when feeding during lactation was less than optimal and this resulted in a significant effect on the rate at which twin lambs were drafted to achieve early season premiums. Lambs failing to reach minimum drafting weights were also penalised because of the prevailing drought conditions and low market prices for lighter lambs. Keywords: breed, dryland, ewes, farming systems, fecundity, milk production, pre-weaning growth, profitability, sheep