Some benefits and costs of genetic improvement in New Zealand's sheep and beef cattle industry

Morris, C. A.

doi:10.1080/03015521.1980.10426283

Cited by 5 publications

(1 citation statement)

References 29 publications

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“…In this trial, a regression of selection line difference on year showed a response of 0.020 (SE 0.011; NS) kg/year, which was slightly lower than the simulation by Morris (1980). He predicted the genetic improvement in a crossbred wool flock of 200 breeding ewes, subject to single trait selection, to be 0.192 kg fleece weight per generation, which was 0.064 kg/year.…”

Section: Discussionmentioning

confidence: 86%

Selection response to fleece weight, wool characteristics, and heritability estimates in yearling Romney sheep

et al. 2011

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Section: Discussionmentioning

confidence: 86%

Selection response to fleece weight, wool characteristics, and heritability estimates in yearling Romney sheep

et al. 2011

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Some benefits and costs of genetic improvement in New Zealand's sheep and beef cattle industry

Morris

1980

New Zealand Journal of Experimental Agriculture

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Estimated physical returns and their calculated value net of food costs have been used as the basis for an analysis of discounted costs and returns from a selection programme for a 200-ewe flock and a 100-cow beef herd. Recording costs (computing, labour, tags, and scales) of $1-2 per ewe and $2-3 per cow are assumed, with a discount rate of 10% as used by the New Zealand Treasury. It is also assumed that no stock for breeding were purchased or sold. Results are expressed in 1979 dollars, for 1 year or round of selection applied. The net present value of 10 years of selection is $4950 or $3600 in sheep ($1 or $2 per ewe in costs) and $3670-4870 in beef cattle, depending on recording costs and the assumed level of food costs incurred by the herd in achieving higher weight-for-age. With sheep, net production is much more important than fleece weight in its contribution to higher profits. A very important contribution in the beef herd under consideration is the return from a higher net calf crop; even small percentage biological gains are of great economic importance. Net returns for a breeder also selling stock for breeding would probably be much higher.

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Objetivos de seleção para sistemas de produção de gado de corte em pasto: ponderadores econômicos

Bittencourt¹,

Lôbo

Bezerra

2006

Arq. Bras. Med. Vet. Zootec.

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RESUMOForam desenvolvidos objetivos de seleção para gado de corte criado nas condições de produção típicas do Brasil Central. As características consideradas foram: número de bezerros desmamados por vaca/ano (NBD), peso da carcaça (PC), peso à desmama (PD) e consumo de alimento. Foram adotados dois sistemas de produção, um que considerava somente a cria e outro, o ciclo completo (cria, recria e engorda). No primeiro, as receitas foram a venda de bezerros à desmama, novilhas excedentes e vacas de descarte. No segundo, a receita foi a venda das novilhas excedentes, vacas de descarte e novilhos para o abate. Em ambas as situações, o lucro (USD/vaca/ano) foi estimado pela diferença entre receita e despesa. Os valores econômicos estimados foram expressos em dólar por unidade de mudança na característica, calculados na base vaca/ano. O valor econômico foi calculado avaliando-se a alteração ocorrida no lucro quando a característica era incrementada de uma unidade, permanecendo as demais inalteradas. A característica que apresentou maior valor bruto do ponderador econômico foi o NBD, seguida pelo consumo, PC e PD. Quando se considerou o valor econômico, em unidades de desvio-padrão genético-aditivo, a ordem de importância foi consumo, PC, NBD e PD.Palavras-chave: bovino de corte, objetivo de seleção, ponderador econômico ABSTRACT Breeding objectives were developed for beef cattle production under typical economic and environmental conditions of central Brazil. The traits considered were: calves weaned per cow/year (NCW), weaning weight (WW), carcass weight (CW) and food intake. In the study, two systems were examined, a cowcalf system (surplus calves sold after weaning) and a cow-calf enterprise (in which surplus calves are raised for slaughter). In the first, income is from the sale of male calves and surplus heifers after weaning and of culled cows. In the second, the income is from the sale of steers, surplus heifers and culled cows. For both situations, the profit (US$/cow/year) was estimated by the difference between revenue and costs. The economical values (EV) were calculated as the change in profit resulting from a unit change in each trait, as other traits remained unchanged. The trait with greatest economic value was NCW, followed by food intake, CW and WW. The order of importance when values were in additive genetic standard deviation units were feed intake, CW, NCW and WW.

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Some benefits and costs of genetic improvement in New Zealand's sheep and beef cattle industry

Cited by 5 publications

References 29 publications

Selection response to fleece weight, wool characteristics, and heritability estimates in yearling Romney sheep

Selection response to fleece weight, wool characteristics, and heritability estimates in yearling Romney sheep

Some benefits and costs of genetic improvement in New Zealand's sheep and beef cattle industry

Objetivos de seleção para sistemas de produção de gado de corte em pasto: ponderadores econômicos

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