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Simple Summary: Improving growth potential and ensuring good meat quality in native chickens were among the key goals in industrial poultry production. This study estimates genetic parameters and correlations of growth, purine content, uric acid, and superoxide dismutase (SOD) activity in Thai native chickens. Findings reveal moderate heritability for growth traits, while biochemical traits showed lower heritability, suggesting potential for selective breeding. The study provides insights to enhance meat quality and antioxidant capacity while balancing growth performance, aiding in breeding programs aimed at sustainable development of Thai native chickens. The objective of this study was to estimate genetic parameters and genetic correlations between growth characteristics and purine and uric acid in the breast and liver and superoxide dismutase (SOD) in the blood. The growth characteristics included body weight (BW) at hatching (BW0), BW at 2, 4, 6, 8, and 10 weeks of age, average daily gain (ADG) at 0–2, 2–4, 4–6, 6–8, and 8–10 weeks of age, and breast circumference at 6, 8, and 10 weeks of age (BrC6, BrC8, and BrC10) were recorded from 300 Thai native chickens (Shee breed). In total, 30 chickens (15 males and 15 females) were randomly euthanized to collect breast meat, liver, and blood samples to determine the purine content. A multiple-trait animal model and an average information-restricted maximum likelihood (AI-REML) were used to estimate the variance components and genetic parameters. The estimated heritability values for all growth traits were moderate and ranged from 0.304 to 0.485, 0.270 to 0.335, and 0.286 to 0.314 for BW, ADG, and BrC, respectively. The estimated heritability values for various biochemical traits, including purine content, uric acid, and SOD levels, were low to moderate and ranged from 0.035 to 0.143, and 0.050 to 0.213 in breast meat and liver, respectively. In genetic correlations, total purine content showed a strong negative correlation with growth traits, whereas uric acid and SOD levels exhibited varying degrees of correlation with BW and ADG. These results highlight the importance of genetic parameters between growth and biochemical traits in Thai native chickens and provide valuable insights for breeding programs aimed at improving growth performance and meat quality. This study indicated the potential use of heritability values and genetic correlations to enhance selective breeding strategies using the multiple-trait genetic evaluation method for optimal trait combinations in poultry. [ABSTRACT FROM AUTHOR]

Simple Summary: Environmental indices are commonly used for detecting heat stress in dairy cattle; however, most studies have only focused on the productivity traits of dairy cattle in response to heat stress and have not considered their health and reproductive characteristics simultaneously. In this study, we aimed to determine the effects of heat stress on the production and reproduction performances of Thai–Holstein dairy cattle and the impact of the genetics of dairy cattle on their heat tolerance. We observed that heat stress significantly reduced milk yield and negatively affected the milk fat-to-protein ratio. Additionally, conception rates declined under heat stress, highlighting the challenges of finding an effective genetic approach for hot and humid regions, including Thailand. Genetic analysis revealed differences in heat tolerance among cows, indicating that the genetic improvement approach used in this study is suitable for planning future genetic improvements in dairy cattle. Heat stress severely affects dairy cattle production and reproduction performances in tropical regions. Genetic selection to maintain adequate yield and reproductive performance while enhancing their ability to withstand heat is essential for improving the genetics of dairy cows. Therefore, in this study, we aimed to estimate genetic parameters affecting production and reproduction performances under heat stress conditions in dairy cattle and to investigate the threshold point of heat stress for milk yield (MY), milk fat-to-protein ratio (FPR), and conception rate (CR) in Thai–Holstein dairy cattle. The data included 168,124 records related to MY and milk FPR and 21,278 records of CR in Thai–Holstein dairy cattle, covering the period from 1990 to 2007. A multiple-trait threshold-linear random regression model based on a Bayesian approach via Gibbs sampling was used to estimate variance components, genetic parameters (heritability values, and genetic correlations), and decline rates for each studied trait. The threshold point of heat stress was identified as a temperature and humidity index (THI) of 76. At THI76, a decline was observed in the MY, milk FPR, and CR of Thai dairy cattle. The heritability estimates for MY, milk FPR and CR were 0.347 ± 0.032, 0.293 ± 0.021, and 0.032 ± 0.001, respectively. The genetic correlation between MY and milk FPR and MY and CR were −0.24 and −0.53, respectively, whereas those between milk FPR and heat tolerance as well as between CR and heat tolerance were −0.48 and −0.49, respectively. In addition, the decline rates in MY, milk FPR, and CR were found to be associated with a high percentage of Holstein genetics. In conclusion, the results obtained in this study reveal that the simultaneous consideration of the MY, milk FPR, CR, and heat tolerance traits of Thai–Holstein dairy cattle is possible. In addition, developing a genetic model that incorporates THI is essential for sustainably addressing heat stress problems. [ABSTRACT FROM AUTHOR]

Simple Summary: Improving the genetic traits influencing rooster semen quality and quantity is crucial for optimizing poultry production. Breeders can identify heritable traits that significantly influence semen characteristics by evaluating genetic parameters, ensuring that only the best roosters are selected for breeding purposes. The development of appropriate genetic models aids in accurately predicting these traits, thereby enhancing selection efficiency. Selection based on these models boosts fertility and hatchability and promotes the propagation of desirable traits across generations. This approach leads to healthier, more productive flocks, increased economic efficiency, and more sustainable poultry farming practices. Improving reproductive traits, particularly semen quality and quantity, is crucial for optimizing poultry production and addressing the current limitations in native chicken reproduction. The aim of this study was to develop a genetic model to estimate genetic parameters guiding the selection of individual Thai native roosters. Using data collected from 3475 records of 242 Thai native grandparent roosters aged 1–4 years, we evaluated semen traits (mass movement, semen volume, and sperm concentration) over 54 weeks. A random regression test–day model incorporating five covariance functions, including a linear spline function with four, five, six, and eight knots (SP4, SP5, SP6, and SP8) and second-order Legendre polynomial function (LG2), was used to estimate genetic parameters. The results showed that the SP8 model consistently outperformed the other models across all traits, with the lowest mean square error, highest coefficient of determination, and superior predictive ability. Heritability estimates for mass movement, semen volume, and sperm concentration ranged from 0.10 to 0.25, 0.22 to 0.25, and 0.11 to 0.24, respectively, indicating moderate genetic influence on these traits. Genetic correlations between semen volume and sperm concentration were highest in the SP8 model, highlighting a strong genetic association between these traits. The SP8 model also revealed a high genetic correlation between mass movement and semen volume, supporting the potential for selecting mass movement as a predictor of semen volume. In conclusion, this study highlights the effectiveness of random regression models with linear spline functions to evaluate the genetic parameters of semen traits in native Thai roosters. The SP8 model is a robust tool for breeders to enhance the reproductive performance of native Thai chickens, contributing to sustainable poultry production systems. [ABSTRACT FROM AUTHOR]

Cooled semen storage methods result in oxidative stress generated by an imbalance between oxidation rates, specifically reactive oxygen species production, and sperm cell antioxidants, leading to degradation of semen quality. We aimed to investigate the impact of adding Eurycoma longifolia (EL) extract as an antioxidant supplement in semen storage medium (IGGKPh semen extender) on semen quality and fertility potential. EL extract at concentrations of 5, 10, 15, and 20 mg/mL was assessed for its antioxidant capacity in IGGKPh semen extender. Our findings revealed that the total phenolic content in the EL extract did not vary significantly across the various concentrations and temperatures tested. However, incubation at 5°C was found to be the most effective temperature for increasing the EL extract antioxidant capacity as assessed via the 2,2-diphenyl-1-picrylhydrazyl inhibition assay in a dosedependent manner. Supplementation of the IGGKPh semen extender with 15 mg/mL EL extract was found to enhance semen quality during cold storage for up to 48 h (p < 0.05), as evidenced by decreased malondialdehyde levels in cooled semen (p < 0.05). However, antioxidant enzyme activities showed no significant differences among the various experimental groups (p > 0.05). The fertility test showed that the 15 mg/mL EL extract group stored for 24 h had a higher percentage than the control group (p < 0.05). However, there was no significant difference in percentage between the two groups at 48 h of storage (p > 0.05). The hatchability showed no significant difference in both 24 and 48-h storage periods (p > 0.05). Our results indicated that supplementing the IGGKPh semen extender with 15 mg/mL EL extract may positively influence semen quality during storage, suggesting potential applications for enhancing semen quality. [ABSTRACT FROM AUTHOR]

Thai native chickens hold significant value in rural communities due to their adaptability and suitability for local rearing conditions. However, there are challenges in the commercial raising of these chickens. This study aimed to evaluate and promote the potential of Thai native chickens (Pradu Hang Dum) for commercial purposes and the development of sustainable native chicken farming. Out of 110 interested farmers, 88 met preliminary conditions and 62 were well-prepared and willing to comply with project conditions. Some farmers were disqualified for not understanding the project conditions or having inadequately prepared chicken coops. The survival rate of native chickens provided to farmers through the project was 52%. Among the surviving birds, 40% were male and 60% were female. The most common causes of death in the project were sickness, accidents, and fighting. The average body weights and average daily gains at different ages were significantly different among farm groups. The average egg production per hatch per hen was 13 ± 2.4 eggs. The highest egg production was in the good farms compared to moderate and poor farms. Better farm management led to higher egg production. In conclusion, this study demonstrates that effective farm management significantly enhances the productivity of Thai native chickens, highlighting their potential as an income-generating activity for rural communities. While challenges such as sickness and accidents impact survival rates, the findings suggest that improved management practices can lead to better production outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: Cooling rooster semen to a temperature of 5 °C is a technique utilized to extend the preservation period of sperm. However, rooster sperm is highly susceptible to damage during preservation, which involves numerous sources of oxidative stress from dilution, limiting its viability and fertility potential to less than 24 h under cool storage conditions. Therefore, researchers are continuously working to optimize preservation methods to enhance the viability and longevity of rooster semen. The aim of this study was to investigate the effectiveness of Aloe vera gel, known for its beneficial antioxidant properties, on the quality of cooled semen in Thai native roosters (Pradu Hang Dum) and to evaluate the fertility rate after artificial insemination. The results showed that Aloe vera gel contained various bioactive compounds with antioxidant activity. The supplementation of the extender with 1.0% Aloe vera gel proved to be beneficial, reducing lipid peroxidation and simultaneously improving sperm quality during cold storage at 5 °C for up to 72 h. The cooling of semen storage at 5 °C from a Thai native rooster (Pradu Hang Dum), supplemented with herbs possessing antioxidant properties, provided limited research. This study was conducted to evaluate the efficiency of Aloe vera (AV) gel supplementation at various levels on the quality of cooled semen and subsequent fertility after artificial insemination. Sixty-four chickens had semen pooled, diluted, and supplemented with different levels of AV gel (0% as control, 0.25%, 0.50%, 1.0%, 2.5%, 5.0%, 10%, and 20%), and then stored for 72 h. In Experiment 1, semen quality, malondialdehyde (MDA) levels, and pH values were assessed at 0, 24, 48, and 72 h after storage. Experiment 2 assessed fertility potential using the most effective cooled storage semen from Experiment 1. Results showed a decrease in semen quality with prolonged storage time (p < 0.001). The highest semen quality was observed in the group supplemented with 1.0% AV gel (p < 0.001), whereas the lowest was noted in the 20% AV gel group (p < 0.001). Furthermore, the 1.0% AV gel group exhibited the highest semen quality at 24, 48, and 72 h of storage. The evaluation of fertility and hatchability rates revealed a statistically significant improvement in fertility potential (p < 0.05) in the group supplemented with 1.0% AV gel. In summary, this study represents the first investigation of stored Thai native rooster semen using a semen extender supplemented with Aloe vera gel at 5 °C, demonstrating its efficacy for storage up to 72 h. The addition of 1% AV gel was recommended as an antioxidant supplementation during the semen storage process at 5 °C to enhance semen quality and fertility rates. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to investigate the effect of heat stress on the growth traits and genetic parameters of Thai native chickens. Methods: A total of 16,487 records for growth traits of Thai native chickens between 2017 and 2022 were used in this study. Data included the body weight at birth, body weight at 4, 8, and 12 weeks of age (BW0, BW4, BW8, BW12), average daily gain during 0 to 4, 4 to 8, and 8 to 12 weeks of age (ADG0-4, ADG4-8, ADG8-12), absolute growth rate at birth, at 4, 8, and 12 weeks of age (AGR0, AGR4, AGR8, AGR12). The repeatability test day model used the reaction-norm procedure to analyze the threshold point of heat stress, rate of decline of growth traits, and genetic parameters. Results: At temperature and humidity index (THI) of 76, Thai native chickens began to lose their growth traits, which was the onset of heat stress in this study. The estimated heritability, genetic correlation between animal and heat stress effect, and correlations between the intercept and slope of the permanent environmental effects were 0.27, -0.85, and -0.83 for BW, 0.17, -0.81, and -0.95 for ADG, 0.25, -0.61, and -0.83 for AGR, respectively. Male chickens are more affected by heat stress than female chickens with a greater reduction of BW, ADG, and AGR, values equal to -9.30, -0.23, -15.21 (in males) and -6.04, -0.21, -10.10 (in females) gram per 1 level increase of THI from the THI of 76. Conclusion: The influence of thermal stress had a strong effect on the decline in growth traits and genetic parameters in Thai native chickens. This study indicated that genetic models used in conjunction with THI data are an effective method for the analysis and assessment of the effects of heat stress on the growth traits and genetics of native chickens. [ABSTRACT FROM AUTHOR]

Objective: Aging roosters typically exhibit subfertility with decreasing semen quality, furthermore Thai native roosters reared in rural areas are raised for a longer duration than their usual lifespan. The present study therefore aimed to assess the effect of selenium supplementation as an antioxidative substance in diets to improve the semen cryopreservation of aged roosters. Methods: Semen samples were collected from young (n = 20) and aged (n = 20) Thai native roosters (Pradu Hang Dum) at 36 and 105 weeks of age when starting the experiment, respectively. They were fed diets either non-supplemented or supplemented with selenium (0.75 ppm). Fresh semen quality and lipid peroxidation of fresh semen was evaluated before cryopreservation using the traditional liquid nitrogen vapor method. Post-thaw sperm quality and fertility potential were determined. Results: Advancing age is unrelated to decreasing fresh semen quality (p>0.05). However, lipid peroxidation in rooster semen depended on age, and the malondialdehyde (MDA) concentration increased in aged roosters (p<0.05). Selenium supplementation in diets significantly decreased the MDA concentration and increased the sperm concentration (p<0.05). In contrast, cryopreserved semen was affected by advancing rooster age, and selenium influenced sperm quality (p<0.05). Younger roosters had higher post-thaw sperm quality and fertility potential than aged roosters (p<0.05). Likewise, diet selenium supplements improved post-thaw sperm quality and fertility compared with the non-supplement group. Conclusion: Rooster's age does not influence the rooster sperm quality of fresh semen, while sperm cryotolerance and fertility were greater in young roosters than in aged roosters. However, sperm of aged roosters could be improved by dietary selenium supplementation. [ABSTRACT FROM AUTHOR]

Simple Summary: Native chickens are vitally important livestock at the community level and represent food security and a source of savings, especially in developing countries where they are considered a valuable genetic resource for use in the development of high-yielding breeds. However, due to the constraints of their slow growth rate, there is an inadequate supply to meet consumer demand. Therefore, genetic improvement for growth traits is one sustainable way to solve these problems. In this study, a multiple trait animal model and selection index are developed as a solution for this problem to improve growth performance in smallholder farms. To ensure that any new technology developed within an experimental station is appropriate to the community's needs and compatible with the existing systems, on-site farm research is an important component in examining the effectiveness of agricultural research. The present study examined the growth performance and genetics of Thai native chickens under conditions typically experienced by farmers on smallholder farms (on-site farms) compared with at an experimental unit (on-station). There were 1694 Thai native chickens (Pradu Hang dum) used in this experiment, and they were divided into 613 chickens for the on-station and 1081 chickens for the on-site farm experiments. The individual chicken data included the birth weight (BW0) and body weight at 4, 8, 12, and 16 weeks of age (BW4, BW8, BW12, and BW16, respectively), ADG from 0–4, 4–8, 8–12, 12–16 weeks of age (ADG0–4, ADG4–8, ADG8–12, ADG12–16, respectively), and breast circumference at 8, 12, and 16 weeks of age (BrC8, BrC12, BrC16, respectively). A multiple traits animal model and a selection index were used to estimate the variance components, genetic parameters, and breeding values of growth traits. The results showed that the body weight, average daily gain, and breast circumference at 8, 12, and 16 weeks of age of Thai native chickens raised on-station were higher than those raised on-site at the farm among mixed-sex and sex-segregated chickens, while the birth weight and body weight at four weeks of age (BW0 and BW4) and ADG from 0–4 weeks of age (ADG0–4) were not significantly different (p > 0.05). The heritability estimates of body weight, average daily gain, and breast circumference in the chickens raised at the on-site farm and on-station were moderate to high, with on-station values slightly higher than on-site farm values. The heritability estimates of body weight were 0.236 to 0.499 for the on-site farm, and 0.291 to 0.499 for on-station. For average daily gain, the heritability estimates were 0.274 to 0.283 for the on-site farm and 0.298 to 0.313 for on-station; meanwhile, and for breast circumference, the heritability estimates were 0.204 to 0.268 for the on-site farm and 0.278 to 0.296 for on-station. Both phenotypic and genetic correlations among and between growth traits were positive and ranged from low to high values. The top 20% of the estimated breeding values and selection indices in the on-site farm and on-station experiments showed that the body weight at eight weeks of age (BW8), ADG from 4–8 weeks of age (ADG4–8), and breast circumference at eight weeks of age (BrC8) should be used as selection criteria for Thai native chicken breeding programs. In conclusion, the genetic parameters and breeding values in on-station experiments showed that the breeding program by selection index for improving growth performance is valid. Therefore, to implement such a breeding program in an on-site farm, an intensive or semi-intensive farm system should be considered to minimize the effect of genotype-environment interaction. [ABSTRACT FROM AUTHOR]