Modelling a Transition from Purebred Romney to Fully Shedding Wiltshire-Romney Crossbred.

Lydia Jane Farrell,Paul R Kenyon,Stephen Todd Morris,Peter R Tozer

doi:10.3390/ani10112066

Abstract

Simple SummaryA flock of full-fleeced ewes could be bred to shed all their fleece through the repeated crossbreeding of ewes with shedding rams. This shedding flock would then not need to have their low value wool removed, thus reducing the associated expenses. This study used a simulation model to explore changes in the sheep numbers of different crosses, production, cashflow, and profit during the crossbreeding period. It took 12–15 years of crossbreeding to achieve a fully-shedding third or fourth cross flock. Economically, crossbreeding to a shedding flock compared favourably with farming a full-fleeced flock. More data on the performance of shedding sheep in New Zealand would improve the accuracy of model predictions.Considering the current low prices for coarse wool (fibre diameter > 30 µm), a grading up transition to a shedding flock may eliminate wool harvesting costs and increase sheep farm profit. This transition could be achieved by breeding non-shedding ewes with Wiltshire rams. A bio-economic system-dynamics model of a pastoral sheep farming enterprise was used to simulate this grading up transition from 2580 Romney ewes to a similarly-sized flock of fully shedding third or fourth cross Wiltshire–Romney ewes. The total annual sheep feed demand was constrained within a ±5% range to minimise disruption to the on-farm beef cattle enterprise. Wool harvesting expenses were eliminated after seven years of transition, and with reduced feed demand for wool growth, the post-transition shedding flocks had more ewes producing more lambs and achieving greater annual profit compared with the base Romney flock. The net present values of transition were 7% higher than the maintenance of the base Romney flock with a farmgate wool price of $2.15/kg. Results suggest that coarse wool-producing farmers should consider a grading up transition to a shedding flock, and the collection of data on the production of Wiltshire–Romney sheep in New Zealand would improve the accuracy of model predictions.

Highlights

The majority of New Zealand sheep are dual-purpose breeds producing coarse wool and lambs for meat production, such as the dual-purpose Romney that makes up 52% of the national flock [1]
net present value (NPV) capture the time value of cashflow during the grading up transition period, accounting for the timing of peak and the nadir total farm cash operating surplus (COS)
Separate NPV analyses were conducted with adjusted wool prices to explore how the potential economic benefits of a grading up transition change with wool returns reflecting recent and possible future prices, where all other parameters were unchanged

Summary

Introduction

The majority of New Zealand sheep are dual-purpose breeds producing coarse wool (fibre diameter > 30 μm) and lambs for meat production, such as the dual-purpose Romney that makes up 52% of the national flock [1]. The majority (76%) of wool produced in New Zealand is exported, and coarse wool is sold at the world market price [1]. The nominal price for coarse wool has fluctuated between NZD 2.99 and $4.98/kg clean between 1990 and 2018 [1] While the average fleece weight of New. Zealand sheep has remained relatively stable over the period of 1990–2018, at 5.2 kg of greasy wool per Animals 2020, 10, 2066; doi:10.3390/ani10112066 www.mdpi.com/journal/animals. Sheep and beef cattle production usually take place on the same farms in New Zealand

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