P. Crosson

Stochastic simulation of the cost of home-produced feeds for ruminant livestock systems

(Received 3 November 2010; revised 1 June 2011; accepted 23 June 2011; first published online 22 July 2011)SUMMARYAn agro-economic simulation model was developed to facilitate comparison of the impact of management,market and biological factors on the cost of providing ruminant livestock with feed grown on the farm (homeproduced feed). Unpredictable year-to-year variation in crop yields and input prices were identified asquantifiablemeasuresofriskaffectingfeedcost.Stochasticanalysiswasusedtostudytheimpactofyieldandinputprice risk on the variability of feed cost for eight feeds grown in Ireland over a 10-year period. Intensively grazedperennial ryegrass was found to be the lowest cost feed in the current analysis (mean cost E74/1000 UniteFourragere Viande (UFV)). Yield risk was identified as the greatest single factor affecting feed cost variability. Atmeanpricesandyields,purchasedrolledbarleywasfoundtobe3%lesscostlythanhome-producedspring-sownbarley. However, home-produced spring barley was marginally less risky than purchased barley (coefficient ofvariation (CV) 0·063 v. 0·064). Feed crops incurring the greatest proportion of fixed costs and area-dependentvariable costs,including bunkergrass silage, were the mostsensitive to yield fluctuations. The mostenergy input-intensive feed crops, such as grass silage, both baled and bunker ensiled, were deemed most susceptible to inputpricefluctuations.Maizesilagewasthemostriskyfeedcrop(CV0·195),withpotentialtobeboththecheapestandthe most expensive conserved feed.INTRODUCTIONForlivestockfarmers,oneofthemostimportantgroupsof management decisions is that relating to feedprovision. McCall & Clark (1999) identified feed costas the primary issue determining the choice of dairysystem in North Eastern USA and New Zealand, whilein Australia Archer et al. (1999) described feed cost asthe greatest input cost group in any animal productionsystem. Feed cost accounts for 0·70–0·75 of all vari-able costs incurred on Irish cattle and sheep farms(Connollyetal.2010).Furthermore,fixedcostsassoci-atedwithfeedproductionandutilization,suchassilos,fencing, buildings and machinery, are an additionalconsideration when costing alternative feeds (Fluck PShallooetal.2004;Belascoetal.2009;Finneranetal.2010b).Computer models have been extensively usedto model the interactions between biological andmanagement variables influencing crop production(McCown et al. 1996; Shaffer et al. 2000; Jones et al.2003; Dobos et al. 2004). Fewer studies used models

The Carbon Navigator: a decision support tool to reduce greenhouse gas emissions from livestock production systems.

The Carbon Navigator has been developed to support the objective of reducing the carbon intensity of the dairy and beef sectors of Irish agriculture. The system is designed as a knowledge transfer (KT) tool aimed at supporting the realisation at farm level of the mitigation potential. The objective of this paper is to outline the potential role of KT in reducing greenhouse gas emissions in the context of a growing body of science, which identifies potential mitigation. The EU policy framework for agriculture and the environment is examined in terms of its effectiveness in supporting the reduction in emission intensity of agriculture. The important role for KT in reducing agricultural emissions is highlighted. The Carbon Navigator is introduced as a potential aid to achieving improved adoption of emission-reducing technologies and practices at farm level. The paper outlines the criteria guiding the selection of mitigation technologies in Irish ruminant agriculture, describes the technologies and practices included in the system and outlines the basis for their inclusion. The approach of developing the Carbon Navigator to integrate into existing infrastructure and data systems as well as into the existing KT systems is outlined.

Analysis of suckler cow reproductive performance and its contribution to financial performance on Irish beef farms

The aim of this study was to analyse cow reproductive performance on 37 Irish suckler beef farms and determine how reproductive efficiency influences farm profitability. The main reproductive factors associated with gross output value per livestock unit (GO/LU) were average age at first calving ( r =−0.19, P r =−0.15, P r =0.21, P r =0.18, P r =0.21, P

Animal performance and economic implications of alternative production systems for dairy bulls slaughtered at 15 months of age

Abstract The objectives of this experiment were to investigate (i) the influence of varying levels of concentrate supplementation during the grazing season, (ii) alternative finishing strategies for dairy bulls slaughtered at 15 mo of age and (iii) economic implications of these management strategies. Bulls were assigned to a 2 (level of concentrate supplementation during the grazing season: 1 kg [LA] and 2 kg [HA] dry matter [DM]/head daily) × 2 (finishing strategies: concentrates ad libitum group [AL] or grass silage ad libitum plus 5 kg DM of concentrates/head daily group [SC]) factorial arrangement of treatments. Average daily gain (ADG) during the grazing season was greater (P < 0.01) for HA than for LA. Consequently, HA bulls were 16 kg heavier at housing: 214 and 230 kg, respectively (P < 0.05). During the finishing period, ADG tended (P = 0.09) to be greater for LA than for HA. Carcass weight tended (P = 0.08) to be greater for HA than for LA. Fat score was greater for HA. Live weight at slaughter (P < 0.001) and carcass weight (P < 0.001) were 41 and 23 kg greater for AL than for SC, respectively. Conformation (P < 0.05) and fat score (P < 0.05) were greater for AL than for SC. The Grange Dairy Beef Systems Model simulated whole-farm system effects of the production systems. Net margin/head was greater for LA than for HA and greater for SC than for AL. Sensitivity analysis of finishing concentrate price, calf purchase price and beef price showed no re-ranking of the systems on a net margin basis. Although greater animal performance was observed from the higher plane of nutrition, overall profitability was lower.