Genetic relationships of fertility traits with test‐day milk yield and fat‐to‐protein ratio in tropical smallholder dairy farms

The test‐day milk fat‐to‐protein ratio (TD‐FPR) could serve as a measure of energy balance status and might be used as a criterion to improve metabolic stability and fertility through genetic selection. Therefore, genetic parameters for fertility traits, test‐day milk yield (TD‐MY) and TD‐FPR, as well as, their relationships during different stages of lactation, were estimated on data collected from 25 968 primiparous Thai dairy crossbred cows. Gibbs sampling algorithms were implemented to obtain (co)variance components using both univariate linear and threshold animal models and bivariate linear‐linear and linear‐threshold animal models with random regression. Average TD‐MY and TD‐FPR were 12.60 and 1.15. Heritability estimates for TD‐MY, TD‐FPR and selected fertility traits ranged from 0.31 to 0.58, 0.17 to 0.19 and 0.02 to 0.05, respectively. Genetic correlations among TD‐FPR and TD‐MY, TD‐FPR and fertility traits, and TD‐MY and fertility traits ranged from 0.05 to ‐0.44, from ‐0.98 to 0.98 and ‐0.22 to 0.79, respectively. Selection for lower TD‐FPR would decrease numbers of inseminations per conception and increase conception at first service and pregnancy within 90 days. In addition, cow selection based only on high milk production has strong effects to prolong days to first service, days open and calving interval.     

Genetic associations between milk fat‐to‐protein ratio,milk production and fertility in the first two lactations of Thai Holsteins dairy cattle

The aims of this study were to estimate, simultaneously, the genetic parameters of test‐day milk fat‐to‐protein ratio (FPR), test‐day milk yield (MY), and days‐open (DO) in the first two lactations of Thai Holsteins. A total of 76 194 test‐day production records collected from 8874 cows with 8674 DO records between 2001 and 2011 from different lactations were treated as separated traits. The estimates of heritability for test‐day FPR in the first lactation showed an increasing trend, whereas the estimates in the second lactation showed a U‐shape trend. Genetic correlations for FPR‐DO and MY‐DO showed a decreasing trend along days in milk (DIM) in both lactations, whereas genetic correlations for FPR‐MY increased along DIM in the first lactation but decreased in the second lactation. Genetic correlations of FPR between consecutive DIM were moderate to high, which showed the effectiveness of simultaneous analyses. Selection of FPR in the early stage has no adverse effect on MY and DO for the first lactation but has a negative effect on MY and positive effect on DO for the second lactation. This study showed that genetic improvement of the energy balance using FPR, MY and DO with multi‐trait test day model could be applied in a Thailand dairy cattle breeding program.     

Targeted identification of association between cotton fiber quality traits and microsatellite markers

Primitive and exotic accessions of cotton are potential sources of favorable alleles for genetic improvement, enriching diversity in the genetically constricted gene pool of elite cultivars. Three exotic accessions of cotton (MDN101, MDN063 and MDN257), collected from different parts of Central America and converted to day-neutral flowering; and four elite cultivars (PD94042, DES56, PMHS200 and Acala Maxxa) representing the US cotton gene pool were used as parents to create experimental populations. The corresponding F₂ and F_2:3 progenies of these populations were grown in two successive years (i.e., some in 2011–2012, some in 2012–2013) and phenotypes were scored in both F₂ and F_2:3 progenies in all 3 years (2011–2012–2013). These populations were screened with 113 polymorphic microsatellite markers selected from “hotspots” for fiber quality quantitative trait loci in the cotton genome and single marker analyses were performed to identify significant associations of the markers with six fiber quality traits. A total of 134 nominal marker-trait associations were identified, among which 15 were significant after Bonferroni correction for multiple comparisons. In 67 of 134 nominal associations and 4 of 15 significant associations, the exotic parents contributed favorable alleles to multiple backgrounds and for multiple traits, in addition to the traits for which they were selected. These results indicate that utilization of exotic and wild accessions of cotton is useful in introducing favorable alleles into the cultivated cotton gene pool for genetic improvement.     

Supplementation effect with slow-release urea in feed blocks for Thai beef cattle—nitrogen utilization,blood biochemistry,and hematology

Four Thai male native beef cattle, initial body weight (BW) of 100?±?3.0 kg were randomly assigned in a 4?×?4 Latin square design to receive four dietary treatments with inclusion of urea calcium sulphate mixture (U-cas) in feed block (FB) at 0, 120, 150, and 180 g/kg dry matter (DM). Total intakes were increased with the increasing level of U-cas supplementation in FB and the result obtained the highest when supplementation of U-cas in FB at 180, followed by 150, 120, and 0 g/kg DM, respectively. Moreover, supplementation of U-cas in FB at 180 g/kg DM could reduce total N excretion (4.1 g/day), as compared to others treatments, while N retention and proportion of N retention to N intake were increased up to 6.9 g/day and 14.9 %, respectively. On the other hand, the blood biochemistry and hematological parameters were not different among treatments except concentration of plasma urea N, plasma glucose, and total blood protein were improved especially with U-cas supplementation at 180 g/kg DM in FB. In conclusion, supplementation of U-cas at 180 g/kg in FB improved feed intake, N utilization, and blood biochemistry in Thai native beef cattle fed on rice straw.     

Carbon Nanostructures Based Mechanically Robust Conducting Cotton Fabric for Improved Electromagnetic Interference Shielding

Herein, an intelligent cotton fabric was fabricated using a non-ionic surfactant based macro structured carbonaceous coating through the ‘knife-over-roll’ technique. The developed novel fabric was tested as flexible, mechanically robust with prolonged chemical/moisture resistance. Various characterization techniques were thoroughly used to analyze the fabric. The as-prepared fabric shows an outstanding electromagnetic interference (EMI) shielding efficiency (SE) of about 21.5 dB even at the lowest possible coating thickness (0.20 mm) where the highest EMI SE of 30.8 dB is obtained at only 0.30 mm coating thickness over the X-band frequency range (8.2-12.4 GHz), possibly due to the three-dimensionally interconnected network structure of conducting carbon particles. The micro-computed tomography disclosed the porous architecture and “void-filler” arrangement within the fabrics. For the betterment of serviceability and practicability of the coated fabric, the water tolerance and contact angle studies were conducted. The relatively high contact angle than pure cotton fabric, and excellent water resistance after coating ensure improved endurance for external or industrial uses. Therefore, this proof-of-construct manifests commercialization of the developed fabric for multipurpose applications in a facile, less-hazardous and economical way.     

Genetic analysis of the rates of conception using a longitudinal threshold model with random regression in dairy crossbreeding within a tropical environment

This study was designed to: (i) estimate genetic parameters and breeding values for conception rates (CR) using the repeatability threshold model (RP‐THM) and random regression threshold models (RR‐THM); and (ii) compare covariance functions for modeling the additive genetic (AG) and permanent environmental (PE) effects in the RR‐THM. The CR was defined as the outcome of an insemination. A data set of 130 592 first‐lactation insemination records of 55 789 Thai dairy cows, calving between 1996 and 2011, was used in the analyses. All models included fixed effects of year × month of insemination, breed × day in milk to insemination class and age at calving. The random effects consisted of herd × year interaction, service sire, PE, AG and residual. Variance components were estimated using a Bayesian method via Gibbs sampling. Heritability estimates of CR ranged from 0.032 to 0.067, 0.037 to 0.165 and 0.045 to 0.218 for RR‐THM with the second, third and fourth‐order of Legendre polynomials, respectively. The heritability estimated from RP‐THM was 0.056. Model comparisons based on goodness of fit, predictive abilities, predicted service results of animal, and pattern of genetic parameter estimates, indicated that the model which fit the desired outcome of insemination was the RR‐THM with two regression coefficients.     

Fate mapping analysis reveals that adult microglia derive from primitive macrophages

Microglia are the resident macrophages of the central nervous system and are associated with the pathogenesis of many neurodegenerative and brain inflammatory diseases; however, the origin of adult microglia remains controversial. We show that postnatal hematopoietic progenitors do not significantly contribute to microglia homeostasis in the adult brain. In contrast to many macrophage populations, we show that microglia develop in mice that lack colony stimulating factor-1 (CSF-1) but are absent in CSF-1 receptor-deficient mice. In vivo lineage tracing studies established that adult microglia derive from primitive myeloid progenitors that arise before embryonic day 8. These results identify microglia as an ontogenically distinct population in the mononuclear phagocyte system and have implications for the use of embryonically derived microglial progenitors for the treatment of various brain disorders.