Quantifying sheep enterprise profitability with varying flock replacement rates, lambing rates, and breeding strategies in New Zealand

Farrell, L.; Kenyon, P. R.; Tozer, Peter R.; Ramilan, Thiagarajah; Cranston, Lydia M.

doi:10.1016/j.agsy.2020.102888

Cited by 20 publications

(15 citation statements)

References 27 publications

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“…In New Zealand commercial flocks, the age at which ewes are culled for age varies between farms, but is typically approximately six to seven years of age [ 1 ], similar to flocks internationally [ 2 , 3 ]. Ewe wastage is defined as the combination of both on-farm mortality and premature culling [ 4 ]. Premature culling is where a ewe is culled prior to the potential end of her productive lifespan.…”

Section: Introductionmentioning

confidence: 99%

“…Increased ewe wastage results in a reduction in farm productivity and subsequent ability to generate profit [ 1 , 4 ]. However, there is limited research on actual wastage rates and causes in commercial ewe flocks in New Zealand [ 1 ] and internationally [ 2 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

“…The mean cumulative incidence of wastage due to premature culling for ewes from each cohort that had a pre-mating BCS of 3.5 3. The mean difference between BCS 2.0 estimate and BCS 3.5 estimate for wastage due to premature culling 4. The mean cumulative incidence of wastage due to dead/missing for ewes from each cohort that had a pre-mating BCS of 2.0 5.…”

mentioning

confidence: 99%

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Ewe Wastage in New Zealand Commercial Flocks: Extent, Timing, Association with Hogget Reproductive Outcomes and BCS

Flay

Ridler

Compton

et al. 2021

Animals

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Ewe wastage is the combination of on-farm mortality and premature culling. Internationally, there is limited research on actual wastage incidence and causes in commercial sheep flocks. To the authors’ knowledge, this is the first study that reports both lifetime wastage and detailed annual wastage in a sample of commercial New Zealand flocks. This study utilized data collected from 13,142 ewes from four cohorts on three commercial New Zealand farms (Farm A 2010-born, Farm A 2011-born, Farm B, Farm C), during the period 2011–2017, as they aged from replacement hoggets to 6-year-old ewes (Farm A and Farm B) or 3-year-old ewes (Farm C). Data collection visits occurred at three or four key management times each year, namely pre-mating, pregnancy diagnosis, pre-lambing and weaning. At each visit, body condition score (BCS) was assessed and any ewes that were culled or had died on farm were recorded. As this was a lifetime study, each ewe was assigned an outcome and corresponding ‘exit age’. By the end of the study, all ewes that had exited their respective flocks, were classified as either prematurely culled, or dead/missing, or if still in the flock, as censored, and either the exact date or interval in which they exited the flock was recorded. Semi-parametric competing risk (premature culling vs. dead/missing), interval-censored survival models were developed to: 1. describe the association between hogget reproductive outcomes and risk of subsequent wastage, and 2. assess pre-mating BCS as a predictor of wastage in that production year. Of the 13,142 enrolled ewes, 50.4% exited their respective flocks due to premature culling and 40.0% due to on-farm dead/missing, giving a total of 90.4% that exited due to wastage. Annual mortality incidence ranged from 3.5 to 40.2%. As a hogget, wastage incidence ranged from 7.6 to 45.4%. Pregnancy or rearing a lamb as a hogget did not increase risk of subsequent wastage. In all years, pre-mating BCS was a predictor of ewe wastage, with odds of wastage lower with increasing BCS. Therefore, farmers should focus on improving pre-mating BCS to 3.5/5.0 by assessing ewe BCS at weaning, allowing poorer-BCS ewes to be managed to gain BCS before re-breeding.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ewe Wastage in New Zealand Commercial Flocks: Extent, Timing, Association with Hogget Reproductive Outcomes and BCS

Flay

Ridler

Compton

et al. 2021

Animals

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“…Feed supply and economics were estimated in component modules for the entire farm. More detail on model workings were reported in [16][17][18][19]. This study extended the previous model to include the option of crossbreeding to a third ( 7 /8W 1 /8R) and/or fourth (straightbred) cross ewe flock.…”

Section: Methodsmentioning

confidence: 89%

“…Only the sheep operations of the farm were analysed in this model as with previous modelling by [16][17][18][19]; producing coarse wool, prime lambs and cull ewes sold direct to slaughter, and store lambs sold to be finished on another farm [2]. Ewes in each age ( i ) class (Y i ) each year were the sum of ewes in the previous age class (Y i−1 ) minus ewes leaving the flock due to deaths (D i−1 ) and culling (C i−1 ) (Equation (1)).…”

Section: Flock Dynamics Of Self-replacing Romney Flockmentioning

confidence: 99%

Modelling a Transition from Purebred Romney to Fully Shedding Wiltshire–Romney Crossbred

Farrell

Morris

Kenyon

et al. 2020

Animals

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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.

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Economic risk assessment of the quality labels and productive efficiency strategies in Spanish extensive sheep farms

Bertolozzi-Caredio

Soriano

Bardají

et al. 2021

Agricultural Systems

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Quantifying sheep enterprise profitability with varying flock replacement rates, lambing rates, and breeding strategies in New Zealand

Cited by 20 publications

References 27 publications

Ewe Wastage in New Zealand Commercial Flocks: Extent, Timing, Association with Hogget Reproductive Outcomes and BCS

Ewe Wastage in New Zealand Commercial Flocks: Extent, Timing, Association with Hogget Reproductive Outcomes and BCS

Modelling a Transition from Purebred Romney to Fully Shedding Wiltshire–Romney Crossbred

Economic risk assessment of the quality labels and productive efficiency strategies in Spanish extensive sheep farms

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