Comparison of random regression and repeatability models to predict breeding values from test-day records of Norwegian goats.

One aim of the research was to challenge a previously selected repeatability model with 2 other repeatability models. The main aim, however, was to evaluate random regression models based on the repeatability model with lowest mean-squared error of prediction, using Legendre polynomials up to third order for both animal additive genetic and permanent environmental effects. The random regression and repeatability models were compared for model fit (using likelihood-ratio testing, Akaike information criterion, and the Bayesian information criterion) and the models' mean-squared errors of prediction, and by cross-validation. Cross-validation was carried out by correlating excluded observations in one data set with the animals' breeding values as predicted from the pedigree only in the remaining data, and vice versa (splitting proportion: 0.492). The data was from primiparous goats in 2 closely tied buck circles (17 flocks) in Norway, with 11,438 records for daily milk yield and 5,686 to 5,896 records for content traits (fat, protein, and lactose percentages). A simple pattern was revealed; for daily milk yield with about 5 records per animal in first lactation, a second-order random regression model should be chosen, whereas for content traits that had only about 3 observations per goat, a first-order polynomial was preferred. The likelihood-ratio test, Akaike information criterion, and mean-squared error of prediction favored more complex models, although the results from the latter and the Bayesian information criterion were in the direction of those obtained with cross-validation. As the correlation from cross-validation was largest with random regression, genetic merit was predicted more accurate with random regression models than with the repeatability model.

Biomarkers of Alzheimer's disease in the cerebrospinal fluid of Spanish patients with mild cognitive impairment.

The study of biomarkers in the cerebrospinal fluid (CSF) of patients with mild cognitive impairment (MCI) is a technique used with increasing frequency in the early diagnosis of Alzheimers disease (AD). Our objectiv was to gain an own experience while evaluating the reliability, sensitivity, and reproducibility of this technique in Spanish patients. Thirty-seven patients with MCI and twenty-four control subjects were studied by means of AD biomarker analysis in CSF. xMAP Luminex and INNO-BIA Alzbio3 reagents of Innogenetics were used. The study variables assessed were levels of Aß(1-42), T-tau and P-tau(181p) proteins as well as the ratios of T-tau/Aß(1-42) and P-tau(181p)/Aß(1-42). Samples from nineteen patients were examined twice. Intra-class correlation coefficients for the three biomarkers used showed values higher than 0.95. We observed significant differences between the control group and the MCI groups. In the 6 months following lumbar puncture (LP), eleven (29%) patients with MCI developed AD. These patients showed significant lower levels in Aß(1-42) protein (276.35 ± 78 vs. 367.13 ± 123.49, P < 0.03) and higher ratios (T-tau/Aß(1-42) [0.38 ± 0.2 vs. 0.22 ± 0.14, P < 0.01] and P-tau(181p)/Aß(1-42) [0.27 ± 0.13 vs. 0.16 ± 0.1, P < 0.008]) to those in the same group who remained stable. We obtained similar results to those in the most recent reliable literature with our ROC curves, especially with our P-tau(181p) values and T-tau/Aß(1-42) ratio in order to differentiate between control and AD groups. Our experience showed that the analysis of CSF-AD biomarkers in patients with MCI is reliable, sensitive and reproducible. In our knowledge, this is the first experience in Spanish patients.

The influence of dietary palm olein, fish oil and lard on the egg yolk and plasma lipid composition, and performances of laying hens.

The influence of dietary palm olein, in comparison to fish oil and lard, on lipid levels in egg yolk and blood plasma, the fatty acid composition of egg yolk, and various production parameters were studied. Brown Lohman laying hens (n=45) were randomly assigned into three groups of 15 birds, and treated with experimental diets with either 3% palm olein (PO), fish oil (FO) or lard (L) for 6 weeks. At the end of the experiment, feed consumption was significantly lower for hens fed the PO diet, except week 6 of the experiment. The concentration of plasma triglycerides was increased by all experimental diets, whereas there were no significant increases of plasma total lipid and total cholesterol concentrations only in the PO group. For yolk lipids a decrease in triglycerides in the FO and L groups was observed, while total cholesterol and total lipid were significantly decreased in the PO group. Feeding with the PO diet resulted in the lowest concentrations of palmitic, stearic and linoleic acid, as well as in the highest concentration of monounsaturated oleic acid in the yolk total lipid. It was concluded that the composition of yolk lipids did not closely match the concentrations of lipids observed in experimental diets or plasma. Based on the current work it seems that the PO diet modulates egg yolk lipid content best.

Papilitis unilateral como presentación de neurosífilis / Unilateral papillitis as the presenting symptom of neurosyphilis

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Genetic diversity and structure of the West Balkan Pramenka sheep types as revealed by microsatellite and mitochondrial DNA analysis.

Several different phenotypes of the native Pramenka sheep have been developed in the Balkan region for different environmental and socio-cultural conditions. Animals from seven West Balkan Pramenka sheep types were analysed for 15 microsatellite markers and for mitochondrial DNA (mtDNA) and the results were used to assess genetic variation within and among the types and to infer the genetic population structure of the Pramenka sheep. Mean expected heterozygosity and allelic richness over the microsatellite loci and sheep types were 0.78 and 7.9, respectively. A Bayesian statistical method for estimating hidden genetic structure suggested that a core of the largest panmictic population was formed by Serbian, Kosovan, Bosnian, Montenegrin and Albanian types, while Croatian and Macedonian types comprised two other main populations, respectively. Mitochondrial DNA analysis revealed two mtDNA haplogroups in the Pramenka sheep, B and A, with a frequency of 93.7% and 6.3%, respectively. A total of 60 mtDNA haplotypes were found in 64 animals sequenced, and the mean nucleotide and haplotypic diversities over the types were 0.013 and 0.945, respectively. Molecular analysis suggests that the West Balkan Pramenka sheep types have their origins in two distinct maternal lineages of domestic sheep and different Pramenka phenotypes tend to form few panmictic populations. The Pramenka sheep represents a valuable resource of genetic diversity in sheep.

Environmental sensitivity of milk production in extensive environments: a comparison of Simmental, Brown Swiss, and Tyrol Grey using random regression models.

A total of 25,160 milk test-day records from 2,516 cows in first lactation of 3 dairy cattle breeds [Simmental (n = 1,900), Brown Swiss (n = 444), and Tyrol Grey (n = 172)] in Kosovo were analyzed using nested repeatability and random regression test-day models with varying (co)variance structures. The different models were compared based on likelihood-based criteria. The best model was a second-order random regression model, with heterogeneous cow variance per breed and heterogeneous residual variance per lactation month and breed, which was used for further analysis. The highest milk production was found in Brown Swiss, followed by Simmental and Tyrol Grey. Substantial breed differences were found for the trajectories of cow and residual variances by month of lactation, with the highest variances found for Brown Swiss, followed by Simmental and Tyrol Grey. High cow and residual variances indicated a high degree of environmental sensitivity on the macro- and microenvironmental levels, respectively. Thus, these results indicate increased environmental sensitivity for breeds with higher genetic potential for milk production. These results support the conclusion that dairy cattle production under the current environmental conditions of Kosovo should be based on a breed with moderate production that is robust to the diet offered (e.g., Tyrol Grey).