Selection indices for residual feed intake derived from milk spectra.

Improving production efficiency and minimizing the environmental impact of dairy farming are 2 important goals of the dairy industry. Achieving these objectives requires improving the feed-to-milk conversion efficiency. One way to achieve this goal is through genetic selection. However, measuring feed efficiency in commercial herds is currently not feasible. As such, we conducted a study to evaluate the genetic accuracy of various selection indices derived from Fourier transform mid-infrared (FTIR)-spectra or milk composition. We use 7,793 weekly records on 537 genotyped cows (78,964 SNPs), with information on residual feed intake (RFI), and FTIR-spectra. We fitted various types of selection indexes using the complete FTIR-spectra of milk samples. The estimated heritability of RFI was 0.12 ± 0.02. The accuracy of indirect selection using the FTIR-spectra was maximized using a principal components selection index (0.16 ± 0.07), followed by a Lasso-type penalized selection index (0.14 ± 0.06). We determined that an index based on milk spectral data recorded on ~25 daughters produced a progeny average with an accuracy comparable to direct phenotypic selection for RFI. We conclude that indirect selection for RFI using FTIR-spectra data can be effective for sires with progeny; however, future studies with a larger sample size are needed to validate these results.

Genomic prediction in biparental tropical maize populations in water-stressed and well-watered environments using low-density and GBS SNPs.

One of the most important applications of genomic selection in maize breeding is to predict and identify the best untested lines from biparental populations, when the training and validation sets are derived from the same cross. Nineteen tropical maize biparental populations evaluated in multienvironment trials were used in this study to assess prediction accuracy of different quantitative traits using low-density (~200 markers) and genotyping-by-sequencing (GBS) single-nucleotide polymorphisms (SNPs), respectively. An extension of the Genomic Best Linear Unbiased Predictor that incorporates genotype × environment (GE) interaction was used to predict genotypic values; cross-validation methods were applied to quantify prediction accuracy. Our results showed that: (1) low-density SNPs (~200 markers) were largely sufficient to get good prediction in biparental maize populations for simple traits with moderate-to-high heritability, but GBS outperformed low-density SNPs for complex traits and simple traits evaluated under stress conditions with low-to-moderate heritability; (2) heritability and genetic architecture of target traits affected prediction performance, prediction accuracy of complex traits (grain yield) were consistently lower than those of simple traits (anthesis date and plant height) and prediction accuracy under stress conditions was consistently lower and more variable than under well-watered conditions for all the target traits because of their poor heritability under stress conditions; and (3) the prediction accuracy of GE models was found to be superior to that of non-GE models for complex traits and marginal for simple traits.

Common variable immunodeficiency, insulin-dependent diabetes mellitus and celiac disease.

Common variable immunodeficiency is a disorder characterised by hypogammaglobulinemia with B-lymphocytes in peripheral blood and repeated infections. We report a child with a diagnosis of diabetes mellitus and celiac disease during lactation, and in whom common variable immunodeficiency was diagnosed at the age of 5. During evolution of the disease he presented multiple respiratory infections in spite of substitution therapy with gamma globulins. He presented pulmonary fibrosis with a pulmonary volume reduced, and a spirometric restrictive patron. Immunologically, he presents reduction in CD4 lymphoid population. He expresses the alleles DQ2 A1 0501 and B1 which are strongly associated with susceptibility to insulin-dependent diabetes mellitus and celiac disease, but don't express antigens HLA class II DR3 and DR4 that are more frequent in these entities. The main disease and all the complications had affected his curve pondostatural.

AIDS risk behavior patterns among intravenous drug users in Puerto Rico and the United States

En este análisis se entrevistaron y analizaron 385 usuários de droga intravenosas reclutados en varios vecindarios del área metropolitana de San Juan. Los usuarios de drogas intravenosas (UDI), independientemente de raza, grupo étnico o medio ambiente geográfico, continúan practicando conductas de riesgo para el contagio del virus de inmuodeficiencia humana (VIH). En general los UDI incluídos en este análisis son jóvenes. Sin embargo, se encontró que los grupos de puertorriqueños e hispanos tenían un nivel de escolaridad menor al de los blancos y negros de los Estados Unidos. El hecho de que casi la mitad de los UDI puertorriqueños reidiendo en los Estados Unidos Continentales reportaran actividades ilegales como fuente de ingreso, sorprendió a los investigadores. Tal y como fuera hipotetizado, casi la mitad de los UDI puertorriqueños en la isla informaron vivir con sus padres. Los UDI en la isla de Puerto Rico continúan practicando conductas de riesgo, se inyectan drogas y utilizan los "hospitalillos" con más frecuencia y son menos propensos a desinfectar las agujas y a utilizar condone que los UDI puertorriqueños, blancos y los negros que residen en los Estados Unidos. Los UDI son el grupo de mayor riesgo para el contagio del síndrome de inmunodeficiencia adquirida (SIDA) entre los puertorriqueños que residen en Puerto Rico y en Estados Unidos. Los UDI son también el grupo con mayor riesgo de contagio heterosexual y la mayor fuente de contagio perinatal de la enfermedad. Por lo tanto, los recursos para prevenir el SIDA en Puerto Rico son más necesarios entre los UDI, donde el 44.5% de los sujetos han obtenido resultados positivos en la prueba del VIH