Economic and genetic performance of various combinations of in vitro-produced embryo transfers and artificial insemination in a dairy herd.

The objective of this study was to find the optimal proportions of pregnancies from an in vitro-produced embryo transfer (IVP-ET) system and artificial insemination (AI) so that profitability is maximized over a range of prices for embryos and surplus dairy heifer calves. An existing stochastic, dynamic dairy model with genetic merits of 12 traits was adapted for scenarios where 0 to 100% of the eligible females in the herd were impregnated, in increments of 10%, using IVP-ET (ET0 to ET100, 11 scenarios). Oocytes were collected from the top donors selected for the trait lifetime net merit (NM$) and fertilized with sexed semen to produce IVP embryos. Due to their greater conception rates, first ranked were eligible heifer recipients based on lowest number of unsuccessful inseminations or embryo transfers, and then on age. Next, eligible cow recipients were ranked based on the greatest average estimated breeding values (EBV) of the traits cow conception rate and daughter pregnancy rate. Animals that were not recipients of IVP embryos received conventional semen through AI, except that the top 50% of heifers ranked for EBV of NM$ were inseminated with sexed semen for the first 2 AI. The economically optimal proportions of IVP-ET were determined using sensitivity analysis performed for 24 price sets involving 6 different selling prices of surplus dairy heifer calves at approximately 105 d of age and 4 different prices of IVP embryos. The model was run for 15 yr after the start of the IVP-ET program for each scenario. The mean ± standard error of true breeding values of NM$ of all cows in the herd in yr 15 was greater by $603 ± 2 per cow per year for ET100 when compared with ET0. The optimal proportion of IVP-ET ranged from ET100 (for surplus dairy heifer calves sold for ≥$300 along with an additional premium based on their EBV of NM$ and a ≤$100 embryo price) to as low as ET0 (surplus dairy heifer calves sold at $300 with a $200 embryo price). For the default assumptions, the profit/cow in yr 15 was greater by $337, $215, $116, and $69 compared with ET0 when embryo prices were $50, $100, $150, and $200. The optimal use of IVP-ET was 100, 100, 62, and 36% of all breedings for these embryo prices, respectively. At the input price of $165 for an IVP embryo, the difference in the net present value of yr 15 profit between ET40 (optimal scenario) and ET0 was $33 per cow. In conclusion, some use of IVP-ET was profitable for a wide range of IVP-ET prices and values of surplus dairy heifer calves.

Enhancement and Obsolescence: Avoiding an "Enhanced Rat Race".

A claim about continuing technological progress plays an essential, if unacknowledged, role in the philosophical literature on "human enhancement." I argue that-should it eventuate-continuous improvement in enhancement technologies may prove more bane than benefit. A rapid increase in the power of available enhancements would mean that each cohort of enhanced individuals will find itself in danger of being outcompeted by the next in competition for important social goods-a situation I characterize as an "enhanced rat race." Rather than risk the chance of being rendered technologically and socially obsolete by the time one is in one's early 20s, it may be rational to prefer that a wide range of enhancements that would generate positional disadvantages that outweigh their absolute advantages be prohibited altogether. The danger of an enhanced rat race therefore constitutes a novel argument in favor of abandoning the pursuit of certain sorts of enhancements.

Plant molecular farming: opportunities and challenges.

Production of foreign molecules in transgenic plants is anticipated to be an alternative to already established, microbial or animal expression systems with lower production costs. This article reviews the different technologies and approaches currently used to produce economically interesting molecules in plants or plant cell cultures, to evaluate their technical feasibility and economic implications, and to assess the potential socioeconomic and environmental impacts deriving from the adoption of molecular farming products.

Análise da curva de crescimento do perímetro escrotal de touros canchim em diferentes sistemas de criação / Canchim bulls scrotal circumference growth curve analysis in different breeding systems / Análisis de la curva de crecimento del perimetro escrotal de toros canchim en diferentes sistemas de cría

O objetivo deste trabalho foi comparar diferentes modelos não lineares para descrever a curva de crescimento do perímetro escrotal (PE) em razão da idade, em touros da raça Canchim, sob diferentes condições de criação. Na análise foram empregadas 37.344 medidas de perímetro escrotal provenientes de 7.552 animais. Os resultados obtidos mostraram que o modelo Logístico foi o que melhor descreveu o crescimento do PE nos diferentes sistemas de criação. O modelo Brody mostrou-se pouco recomendado para o ajustamento dos dados de PE em função da idade.

The objective of this study was to compare different non linear models in order to describe the Canchim bulls’ age-related scrotal circumference (SC) growth curve measurements in different breeding systems. The data consisted of 37.344 measures from 7.552 Canchim bulls. The results showed that the Logistic model was the one which best described the growth of SC on Canchim bulls in different breeding systems. The Brody model presented the worst adjustments to SC data because of age.

El objetivo de este trabajo fue comparar diferentes modelos no lineares para describir la curva de crecimiento del perímetro escrotal (PE) en función de la edad, en toros de la raza Canchim, en diferentes condiciones de cría. En el análisis fueron utilizadas 37.344 medidas del perímetro escrotal oriundas de 7.552 animales. Los resultados obtenidos mostraron que el modelo Logístico fue el que mejor describió el crecimiento del PE en los diferentes sistemas de cría. El modelo Brody es poco recomendado para el ajuste de los datos de PE en función de la edad.

Pubertad y circunferencia escrotal en toros Holstein x Cebu, Cebu y Romosinuano / Puberty and scrotal circumference in Holstein x Zebu, Zebu and Romosinuano bulls

Objetivo. Establecer la relación entre la pubertad y la circunferencia escrotal en toros de las razas holstein, Cebu y romosinuano. Materiales y métodos. Se tomaron 8 machos F1 Holstein x Cebú (HxC), 8 Cebúes y 10 Romosinuanos, a partir del destete. En los grupos HxC y Cebú, durante la fase de experimentación se realizó evaluación de medidas testiculares (circunferencia escrotal, longitud individual), peso corporal con ayuno de 12 horas, perímetro toráxico y alzada a la cruz. Desde el destete hasta los 12 meses de edad las medidas se realizaron cada 28 días. Posterior a los doce meses las evaluaciones se llevaron a cabo cada 15 días y en cada evaluación se realizó colecta de semen medianteelectroeyaculador. Resultados. Se presentaron diferencias estadísticas para la edad a la pubertad entreel Cebú y los grupos raciales HxC y Romosinuano p<0.0003); siendo la raza Romosinuano la de menor edad a la pubertad, igualmente, se confirmo el efecto de la heterosis sobre la edad a la pubertad con el grupo racial HxC siendo el de menor edad a la pubertad. Para el peso a la pubertad se presentaron diferencias estadísticas significativas para los tres grupos raciales (p<0.0001), siendo los toros Cebú los más pesados y los Romos los de menor de peso. Asimismo para la CE se presentan diferencias entre el Romosinuano y los grupos raciales HxC y Cebú (p<0.0045) a la pubertad, siendo la raza Cebú la que presenta los mayores valores. En los grupos raciales HxC, Cebú y Romosinuano, tantoen pre y pospubertad, las correlaciones entre CE con edad, peso, longitud testicular, perímetro toráxico,alzada a la cruz, y alzada al anca para Romosinuano son altas (r>0.8). Conclusión. Teniendo presente los resultados obtenidos se concluyó que la raza criolla romosinuano presentó menor edad a la pubertad que el Cebú y se confirmó además, el efecto de la heterosis sobre la edad a la pubertad con el grupo racial HxC, el cual tuvo una menor edad a la pubertad.

Engineering genetic injustice.

In their jointly written book, From Chance to Choice: Genetics and Justice, Allen Buchanan, Dan Brock, Norman Daniels and Daniel Wikler defend 'the development and deployment of genetic intervention technologies..', including genetic enhancements, against charges that they exacerbate injustice. The present paper examines some of their arguments. The first section shows that the authors confuse real societies with just societies. The second shows that without this confusion, their arguments reveal the enormous justice-impairing potential of deploying genetic enhancements in such societies as the United States.

The inevitability of genetic enhancement technologies.

We outline a number of ethical objections to genetic technologies aimed at enhancing human capacities and traits. We then argue that, despite the persuasiveness of some of these objections, they are insufficient to stop the development and use of genetic enhancement technologies. We contend that the inevitability of the technologies results from a particular guiding worldview of humans as masters of the human evolutionary future, and conclude that recognising this worldview points to new directions for ethical thinking about genetic enhancement technologies.

The genetic difference principle.

In the newly emerging debates about genetics and justice three distinct principles have begun to emerge concerning what the distributive aim of genetic interventions should be. These principles are: genetic equality, a genetic decent minimum, and the genetic difference principle. In this paper, I examine the rationale of each of these principles and argue that genetic equality and a genetic decent minimum are ill-equipped to tackle what I call the currency problem and the problem of weight. The genetic difference principle is the most promising of the three principles and I develop this principle so that it takes seriously the concerns of just health care and distributive justice in general. Given the strains on public funds for other important social programmes, the costs of pursuing genetic interventions and the nature of genetic interventions, I conclude that a more lax interpretation of the genetic difference principle is appropriate. This interpretation stipulates that genetic inequalities should be arranged so that they are to the greatest reasonable benefit of the least advantaged. Such a proposal is consistent with prioritarianism and provides some practical guidance for non-ideal societies--that is, societies that do not have the endless amount of resources needed to satisfy every requirement of justice.

Should we design our descendants?

Rapid breakthroughs in genetic research spurred by the Human Genome Project, advances in molecular biology, and new reproductive technologies are raising the prospect that we may eventually have the technical capacity to modify genes that are transmitted to future generations not only to treat or eliminate diseases but also to "enhance" normal human characteristics beyond what is necessary to sustain or restore good health. This paper explores the ethical and justice implications of such genetic modifications. It argues against developing these technologies primarily because it will not be possible to counter the deleterious justice impacts. It recommends the need for public education and public discussion, preferably with the religious community taking an active role, to shape decisions about future genetic research and applications, and for better regulation of genetic technologies with the potential for inheritable genetic alterations.

Herd behavior in designer genes.

The ability of individuals to choose their children's genes has increased over time and may ultimately culminate in a world involving free market reprogenetic technologies. Reprogenetic technologies combine advances in reproductive biology and genetics to provide humans increased control over their children's genes. This Article offers economic perspectives that are helpful in understanding the possibly unexpected ethical, legal, and social issues at stake in using reprogenetic technologies for trait enhancement selection. The Appendix analyzes two competitive games that might arise in such a biotechnological society. Specifically, the Article focuses on herd behavior, caused by either a popularity contest or positional competition, in the choice of genetic traits. The analytical game-theoretic models in the Appendix can have several equilibrium outcomes in terms of individual reprogenetic technological choices and corresponding beliefs about such choices by others. This multiplicity of potential social outcomes suggests that a society can attain efficiency if the state or some private organization transforms individual parents' beliefs over the choices of other parents regarding their children's traits and, thus, coordinates parental reprogenetic decisions by selecting, as focal, certain beliefs over parents' reprogenetic decisions.