Simulation of production systems in East Africa by use of interfaced forage and cattle models

Sullivan, Gregory M.; Cartwright, T. C.; Farris, Donald E.

doi:10.1016/0308-521x(81)90038-x

Cited by 16 publications

(4 citation statements)

References 16 publications

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“…It is a generalized model for simulating beef cattle production under a wide range of management schemes and environments with cattle differing widely in genotypes for size, growth and milk production. The model has been used to simulate beef cattle production under a wide range of climatic and management conditions in Guyana (Davis et al, 1976), Colombia (Cartwright et al, 1977), Venezuela (Ordonez, 1978), Botswana (ILCA, 1978), Tanzania (Sullivan et al, 1981), central Texas (Nelsen et al, 1978) and the mid-western United States (Notter et al, 1979a, b, c).…”

Section: Introductionmentioning

confidence: 99%

Index selection of beef cattle for growth and milk production using computer simulation modelling

Dzama

Walter²,

Ruvuna³

et al. 2001

SA J. An. Sci.

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The Texas A&M University (TAMU) Beef Cattle Production model was expanded to include basic concepts of quantitative genetics. The traits simulated were birth weight, yearling weight, mature weight and milk production. The progeny inherited attributes from both the sire and the dam. The incorporation of genetic concepts into the model allowed for the introduction of variation between individuals and generations. This was achieved by interfacing the original model with stochastic genetic subroutines including a restricted selection index for desired genetic change. The index included birth weight and yearling weight. In addition, a function for estimating dystocia was also added. The model was used to simulate selection strategies for a small-to-moderate size breed of cattle and a large-size breed using a restricted selection index.There was an increase in both birth and yearling weight after 20 years of selection in the small-tomoderate size breed, and there was also an increase in dystocia. Antagonistic selection to decrease birth weight and increase yearling weight was simulated for the large breed. Birth weight and dystocia problems declined while yearling weight increased for all classes of animals. In both experiments correlated responses were recorded for mature size and milk production. It was concluded that the modified TAMU Beef Cattle Production model offers breeders an opportunity to compare different selection strategies and evaluate different breeding plans.

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Section: Introductionmentioning

confidence: 99%

Index selection of beef cattle for growth and milk production using computer simulation modelling

Dzama

Walter²,

Ruvuna³

et al. 2001

SA J. An. Sci.

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“…Results of our simulations emphasized that production adjustments, particularly the adjustments of area of grassland harvested and the possibility to purchase substitutes to on-a) b) farm forage production improve farmers profit under weather variability. These results are corroborated by empirical analysis Mosnier et al 2010) and by simulation studies (Sullivan et al, 1981 ;Gillard and Monypenny, 1990 ;Romera et al , 2005 ;Diaz-Solis et al, 2006 ;Kobayashi et al, 2007;Jouven and Baumont, 2008). However, the highest the cost to buy feed is, the most incentives farmers have to be self sufficient under weather uncertainty.…”

Section: Discussionmentioning

confidence: 73%

On-Farm Weather Risk Management in Suckler Cow Farms: A Recursive Discrete Stochastic Programming Approach

Mosnier

Agabriel

Lherm

et al. 2011

Bio-Economic Models Applied to Agricultural Systems

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Currently France wants to introduce a weather risk management framework into its agricultural policy for livestock farming. The aim of this paper is to better understand how on-farm risk reducing strategies modify the production system and profit distribution of French suckler cow enterprises. We present in this paper an original bioeconomic model that takes into account both risk anticipation and risk adjustments and that details biotechnical relationships between the different components of the beef cattle production system and their dynamics. On-farm risk management strategies are endogeneized under weather uncertainty and tested on real observed weather sequences. We simulate four scenarios characterized by different risk aversions and feed prices. Results emphasized that production adjustments, particularly the adjustments of area of grassland harvested and the possibility to purchase substitutes to on-farm forage production, improve farmers profit under weather variability. However, limiting the amplitude of these adjustments helps decreasing profit variability. All simulated long term decisions associated to risk reducing strategies encompass a reduction of long term stocking rate and the constitution of feed stocks. The impact of hay feed price on the market has similar effects on the long term strategy.

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“…Globalement, nous avons observé que tous les éleveurs s'ajustaient aux aléas climatiques en complémentant les animaux (achat de fourrages et de concentrés) et en modifiant la part des surfaces fauchées et que ces aléas affectaient les charges et le revenu des éleveurs. Ces observa-tions confortent les résultats des travaux de simulations : Romera et al (2005) et Jouven et Baumont (2008 mettent en avant l'intérêt de la modification des fauches, Sullivan et al (1981), Gillard et Monypenny (1990) ou Diaz-Solis et al (2006) soulignent les bénéfices apportés par la complémentation en cas de sècheresse dans des environnements semiarides. C'est aussi cette combinaison d'ajustements qui est apparue «optimale» pour les élevages de bovins allaitants du Charolais dans les simulations de Mosnier et al (2009).…”

Section: / Discussion De La Sensibilité Des Exploitations Aux Aléasunclassified

Évolution et sensibilité aux aléas des résultats technico-économiques des exploitations de bovins allaitants selon les profils de production

et al. 2010

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Les éleveurs de bovins sont confrontés à une évolution continue du contexte socio-économique et à des conditions climatiques et économiques aléatoires. Nous cherchons à déterminer à travers une analyse statistique si des exploitations disposant de plus grandes sources de flexibilité sont moins sensibles à ces aléas et si leurs revenus moyens s’en ressentent. A partir des données technico-économiques d’un panel de 55 exploitations du bassin Charolais sur la période 1987-2007, nous avons dégagé trois profils de production sur la base de critères relatifs à l’engraissement des mâles et au chargement. Des cycles de production plus longs confèrent une plus grande diversité d’animaux commercialisables à court terme et un faible chargement diminue les risques de pénurie en fourrages. Nos analyses montrent que ce sont les éleveurs avec le chargement le plus élevé qui ajustent le plus leurs itinéraires de production via la complémentation des animaux et la part des surfaces en prairies fauchées, et, qui ont les résultats économiques les plus sensibles aux aléas climatiques. Les éleveurs engraissant le plus d’animaux ont eu des revenus moins sensibles aux aléas de prix. Il n’y a en revanche pas de différences significatives de revenus moyens selon les profils. L’analyse des évolutions de long terme révèle que les éleveurs ont tous modifié leur exploitation via l’agrandissement, l’intensification de la production à l’animal et la diminution de la part des mâles engraissés. Les exploitations les moins chargées semblent aller vers une extensification encore plus prononcée de la gestion des surfaces fourragères.

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Simulation of production systems in East Africa by use of interfaced forage and cattle models

Cited by 16 publications

References 16 publications

Index selection of beef cattle for growth and milk production using computer simulation modelling

Index selection of beef cattle for growth and milk production using computer simulation modelling

On-Farm Weather Risk Management in Suckler Cow Farms: A Recursive Discrete Stochastic Programming Approach

Évolution et sensibilité aux aléas des résultats technico-économiques des exploitations de bovins allaitants selon les profils de production

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