Animal Breeding Research Articles

Marker Assisted Selection: A Novel Approach for Crop Improvement

The process of marker-assisted selection, or marker-aided selection (MAS), selects a trait of interest indirectly by considering a marker linked to the trait (e.g., quality, productivity, disease resistance, and biotic stress tolerance) rather than the trait itself. This integration of marker data with traditional selection approaches has become a widely studied and recommended method for advancing breeding programs. This technique has been extensively researched and recommended for animal and plant breeding. Here, we combine marker data with conventional selection to choose the best candidate for a future breeding program. Nowadays, the majority of MAS investigations employ DNA-based markers such as microsatellites, single nucleotide polymorphisms (SNPs), random amplification of polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), and restriction fragment length polymorphism (RFLP). In this case, we discussed several kinds, techniques, and other features of marker Assisted Selection.

Linkage Disequilibrium in Animal Genetics – Definition, Measures and Applications

The non-random connection of alleles at various loci is known as linkage disequilibrium (LD). Combinations of alleles inside haplotypes occur at frequencies that differ from those expected on the premise of independence when two alleles at two distinct loci are in LD. When genetic variation at a locus is linked to a trait, it means that either the genetic variation at that locus directly impacts the phenotype of interest or the locus is in LD with the causal mutation. The level of LD, which dictates how many markers should be typed in a genome scan to discover a quantitative trait locus (QTL) using LD, is critical to the practicality of association studies. This review explores the origin of LD in genetics and how it applies to animal breeding and genetics.

Steady existence of Escherichia coli co-resistant to carbapenem and colistin in an animal breeding area even after the colistin forbidden

Carbapenem- and colistin-resistant Escherichia coli (CCREC) cause high mortality rates and health costs, and have become serious health concerns. Total 1764 samples were collected from 60 animal farms in 2019 and 2021, including worker and animal faeces, wastewater, well water, air, vegetables, human hands, object surfaces, throat swabs, soil, and flies to investigate the prevalence and potential transmission pathways of CCREC. Eleven CCREC were detected: 9 (5 in 2019 and 4 in 2021) from 5 worker faeces, 3 animal faeces, 1 wastewater, and 2 from 1 flies sample. Chicken farms had the highest number of CCREC (n = 9). The detection rate was low (<1.1%) overall, and there was no significant difference in both years, indicating that CCREC existed stably after 4 years of colistin ban. The combinations of chromosomes and plasmids harbouring blaNDM and mcr-1.1 were divided into 4 patterns: IncX3 plasmid-blaNDM & chromosome-mcr.1.1 (n = 5); IncX3 plasmid-blaNDM & IncHI2 plasmid-mcr.1.1 (n = 3); IncFII plasmid-blaNDM & IncI2 plasmid-mcr.1.1 (n = 2); both chromosome (n = 1). The blaNDM located on plasmids was surrounded by similar genetic structures: Tn3-IS-blaNDM-bleMBL-TrpF-DsbD-IS. The genetic contexts of mcr-1.1 were highly similar, with ‘ISApl1-mcr-1.1-PAP2’ and ‘mcr-1.1-PAP2’. All plasmids can be successfully transferred into E. coli J53, except for the IncHI2 plasmids with the transfer rate of 33.3%. The IncFII and IncI2 plasmids from same strain of flies could be co-transferred. The clonal spread of CCREC from humans to humans occurred on the same pig farm (P4) or different chicken farms (BC9 and LH7). This study suggested that flies, chromosomes, and plasmids jointly contribute to the steady existence of CCREC.

Antibiotic Residues in Cultured Fish: Implications for Food Safety and Regulatory Concerns

Antibiotics are widely recognized as significant chemical pollutants that enter the environment and ultimately the food chain. They are extensively used in both aquaculture and terrestrial animal breeding. Antibiotic residues in cultured fish pose significant public health risks, including the potential for antimicrobial resistance and adverse health outcomes. This review examines the widespread use of antibiotics in aquaculture, highlighting key challenges such as the lack of reliable data on antibiotic consumption in many regions as well as variability in regulatory enforcement. While strict regulations in European countries help to mitigate risks, the growing, often unregulated use of antibiotics in low- and middle-income countries exacerbates concerns over food safety. This paper provides an in-depth analysis of global regulatory frameworks and the impact of antibiotic residues on public health, and it offers recommendations for improving the monitoring, regulation, and responsible use of antibiotics in aquaculture in order to ensure safer food products from farmed fish. It contributes to a deeper understanding of the global scope of antibiotic misuse in aquaculture and points to an urgent need for more effective management practices.

Lateral flow immunoassay based on aggregation induced emission nanobeads for the sensitive and accurate detection of chloramphenicol in pig hair

Chloramphenicol (CAP) is a once widely used antibiotic, which is able to cause great harm to human health, is banned in some countries or organizations such as China, USA and the European Union for animal breeding. Because CAP in pig hair degraded slower and had amount of residues, pig hair could be used as the target to detect CAP residues. In this study, a competitive lateral flow immunoassay (LFIA), whose label was aggregation induced emission fluorescent nanobeads (AIEFN), was firstly developed for the detection of CAP in pig hair samples. It exhibited a low limit of detection (0.001 μg/kg) and a broad linear range (0.0025–0.32 μg/kg). The recovery rate and coefficient variation with spiked pig hair samples were 88.50%–106.17 % and 1.01%–7.37 %, which indicated good accuracy of this assay. The result of AIEFN-LFIA for the detection of CAP in pig hair was consistent with that of liquid chromatography-mass spectrometry. This assay was rapid with the total detection duration of about 20 min. AIEFN-LFIA was able to be used for rapid, sensitive, accurate and convenient detection of CAP residues in pig hair samples.

Simultaneous Analysis of Imidazole Dipeptides, Constituent Amino Acids, and Taurine in Meats Using the Highly Sensitive Labeling Reagent l-FDVDA and PBr Column.

Imidazole dipeptides (IDPs) are found in the skeletal muscles and brains of various animals, and they exhibit unique functions like antioxidant and antiaging properties. Despite their importance, the metabolic mechanisms and physiological roles of IDPs remain unclear. Herein, we propose a method for the simultaneous analysis of IDPs, their constituent amino acids, and taurine, which are difficult to separate using conventional labeling reagents or columns, using liquid chromatography-single quadrupole mass spectrometry with PBr column and our highly sensitive labeling reagent, 1-fluoro-2,4-dinitrophenyl-5-l-valine-N,N-dimethylethylenediamineamide (l-FDVDA). This method successfully separated histidine and carnosine enantiomers as well as l-2-oxocarnosine with high antioxidant activity under the same conditions. Our labeling reagent was more stable than the other reagents and did not degrade and desorb from the analytes for at least 1 week at 4 °C. Furthermore, our method allows for the accurate analysis of IDPs, amino acids, and taurine in meats from various animal species, tissues, and breeds.

Paeonol attenuates LPS-induced inflammatory injury in mastitis by regulating the MAPK and Nrf2 signaling pathways

Mastitis is an inflammatory udder disease that causes important economic losses in the animal breeding and dairy product industries. While antibiotics have contributed to disease control, their use presents risks due to drug residues in livestock products that can potentially threaten human health. Paeonol, an active ingredient extracted from the dried root bark of paeonia suffruticosa, exhibits various pharmacological effects, including anti-inflammatory and antibacterial properties, but its role in mastitis remains unclear. In this study, we first evaluated the effects of paeonol on LPS-induced mastitis in mice and further explored the potential anti-inflammatory mechanism of paeonol on bovine mammary epithelial cells (BMECs). The results showed that paeonol alleviated LPS-induced mouse mastitis by inhibiting the infiltration of inflammatory cells and the release of inflammatory factors. Cellular assays further demonstrated that paeonol reduced apoptosis and inhibited inflammation and oxidative stress injury by mechanisms involving activation of Nrf2 signaling and inhibition of MAPK signaling in BMECs. Collectively, our results suggest that paeonol holds promise as a therapeutic agent for alleviating LPS-induced mastitis injury while providing novel insights into potential drug targets for mastitis treatment.

Antibacterial Effect of Fermented Pomegranate Peel Polyphenols on Vibrio alginolyticus and Its Mechanism.

Vibrio alginolyticus frequently breaks out in aquatic animal breeding operations involving shrimp, and it can endanger human health through food and wound infections. The antibacterial effect and mechanism of fermented pomegranate peel polyphenols (FPPPs) on V. alginolyticus were investigated. The results indicated that FPPPs had a strong inhibitory effect on the growth of V. alginolyticus, and their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were 2 and 4 mg/mL. FPPPs significantly reduced biofilm formation and biofilm metabolic activity in V. alginolyticus, down-regulated the expression levels of lafA, lafK, fliS and flaK genes involved in flagellar synthesis and inhibited swimming and swarming motility (p < 0.05). Meanwhile, under the treatment of FPPPs, the activities of catalase (CAT) and superoxide dismutase (SOD) in V. alginolyticus were significantly reduced, and the levels of reactive oxygen species (ROS) and extracellular malondialdehyde (MDA) were significantly increased (p < 0.05). FPPPs also resulted in a significant increase in alkaline phosphatase (AKP) activity, protein and nucleic acid content, as well as conductivity from V. alginolyticus cultures. Scanning electron microscopy (SEM) images further revealed that V. alginolyticus treated with FPPPs showed leakage of intracellular substances, abnormal cell morphology and damage to cell walls and cell membranes, with the severity of the damage in a clear dose-dependent manner. Therefore, FPPPs can be used as a promising food-grade antibacterial agent, notably in seafood to control V. alginolyticus.

CRISPR-Cas9: Revolutionizing Crop Resistance Enhancemement

Abstract. The security of food has grown to be a serious concern in recent years, due to factors such as environmental changes, pest infestations affecting crop yields and food safety. Traditional breeding methods, such as hybrid breeding, often involve long cycles, consuming substantial human and material resources and constrained by germplasm limitations, significantly hindering the rapid development of animal and plant breeding. In contrast, CRISPR-Cas9 genome editing technology allows precise modification of genetic information inanimals and plants at the molecular level, directly optimizing target traits or imparting new genetic characteristics, demonstrating more direct and efficient breeding advantages compared to traditional methods. The implementation and advancement of the CRISPR-Cas9 genome editing system to increase plant and animal resilience is the main topic of this review, which also discusses its drawbacks and potential applications.

Breeding evaluations in aquaculture using neural networks

Deep learning comes with a portfolio of highly flexible models, known as neural networks (NNs), capable of solving various problems and setting new high standards for prediction accuracy. Nevertheless, whether NNs could be of value in aquaculture selective breeding settings is unclear as the whole topic is underexplored. Furthermore, fine-tuning a plethora of hyperparameters before fitting a neural network is a daunting task. Using simulated and a publicly available dataset on genetic resistance in carp against koi herpes virus (KHV), various neural network architectures were benchmarked against commonly used animal breeding models. More specifically, the simulated datasets comprised 36000 phenotyped animals genotyped for 54000 single nucleotide polymorphisms (SNPs). In contrast, the carp dataset included 1255 carp juveniles with survival recordings for KHV that were genotyped for 15615 SNPs. The assessed NN architectures included multilayer perceptrons (MLPs), convolution neural networks (CNNs) and local convolution neural networks (LCNNs). In addition, the effect of various hyperparameters of neural networks, such as the number of hidden layers, neurons per layer, activation function, learning rate, batch size, and regularisation techniques like dropout, were examined. In the simulated datasets, fully connected models with 5 hidden layers and 100 neurons per layer performed slightly better (1 – 4 %) than ridge-regression best linear unbiased prediction (rrBLUP), while the CNNs gave the lowest prediction accuracies (∼ 14 % lower than MLPs) and the ones from LCNN in between the above (∼ 8 lower than MLPs). Nevertheless, the estimated breeding values from NNs appeared more biased than rrBLUP (mean regression slope of 1.2 for the NN with the highest prediction accuracy vs 1.08). A reverse picture was observed in the case of the carp dataset, where following the application of receiver operating characteristic (ROC) curves, the animal breeding models outperformed neural networks by more than 2 % (based on the area under the curve index). In this case the LCNN had the highest area under the curve index from all NNs. Overall, NNs could be valuable tools in aquaculture breeding programs, though large training datasets of tens of thousands or more of phenotyped and genotyped animals seem to be required.

Predicting the body weight of crossbred Holstein × Zebu dairy cows using multivariate adaptive regression splines algorithm.

This study aimed to estimate live body weight from body measurements for Holstein × Zebu dairy cows (n = 156) reared under conditions of humid tropics in Mexico using multivariate adaptive regression splines algorithm (MARS) with several train-test proportions. The body measurements included withers height, rump height, hip width, heart girth, body length and diagonal body length. The data were divided into 65:35, 70:30 and 80:20 split data for training and testing sets, respectively. The MARS algorithm was used to construct a prediction model, which predicted the body weight from the body measurements of the test dataset. The results emphasized that the MARS algorithm had an explanation rate for 80:20 train and test set of 0.836 and 0.711, respectively, with minimum Akaike information criterion values. This indicates that it is a reliable way of predicting body weight from body measurements. The results suggest that body weight prediction can be performed with the MARS algorithm in a reliable way, therefore, this algorithm may be a useful tool for animal breeders and researchers in the development of feeding and selection-aimed approaches.

Sorption of the emerging pollutant oxytetracycline on eggshell. Experimental and theoretical approaches

The constant use of drugs for health treatments increases the presence of antibiotics, analgesics, antipyretics and hormones in wastewater and water bodies, negatively affecting the biosphere. Among the emerging pollutant sources, the main are wastewater, hospital effluents, agriculture, animal breeding and improper management of industrial effluents. Therefore, it is essential to develop or adapt methods to remove these pollutants from environmental matrices. This work studies experimental and theoretically the removal of the widely used antibiotic oxytetracycline (OTC) from water through its sorption by a globally abundant solid waste: eggshell (ES). Experimentally, the OTC sorption by ES powders has been performed at different OTC concentrations. The obtained isotherm has been fitted by the Langmuir, Freundlich and Sips models. Theoretically, first principles calculations to model the OTC molecule on different CaCO3 surfaces were done. Experimentally the maximum sorption capacity was 15 ± 3 mg/g at RT, disclosed by the best model representing the data, the Langmuir one at a single site. Theoretically OTC sorption involves the interaction between Ca2+ of ES and O atoms of OTC. Therefore, ES waste is a promising material for low-cost remediation technologies based on the sorption process for the treatment of waters containing OTC.

Cordycepin improves hyperactivation and acrosome reaction through adenosine receptors during human sperm capacitation in vitro

BackgroundSperm capacitation is a prerequisite for natural or in vitro fertilization. After capacitation, sperm become hyperactivated and undergo an acrosome reaction, which helps them penetrate the oocyte. Cordycepin, a bioactive compound first isolated from Cordyceps militaris, is an adenosine analog with numerous physiological activities. However, its effects on sperm capacitation remain unclear. This study aims to elucidate the effects and mechanisms of cordycepin on human sperm capacitation.MethodsDuring in vitro capacitation culture, healthy human sperm were treated with cordycepin (20, 100, 500 µM). Sperm motility and hyperactivation were detected using a computer-assisted sperm analyzer. Sperm acrosome reaction was measured using fluorescein isothiocyanate-conjugated Pisum sativum agglutinin. Sperm protein kinase A (PKA) activity was analyzed using an ELISA kit. The levels of sperm protein tyrosine phosphorylation were detected by western blotting. Sperm DNA damage was detected by a sperm chromatin dispersion assay. Reactive oxygen species (ROS) were measured using the fluorescence probe 2′,7′-dichlorodihydrofluorescein diacetate. The expression and localization of adenosine receptors were analyzed by western blotting and immunofluorescence. The specific inhibitors of adenosine receptors were used to confirm their effects on cordycepin-induced sperm capacitation. Finally, molecular docking was performed to analyze the interaction between cordycepin and adenosine receptors.ResultsCordycepin improved hyperactivated sperm motility, acrosome reaction, PKA activity, and protein tyrosine phosphorylation during capacitation while having no obvious effects on sperm ROS or DNA damage. Four adenosine receptor subtypes were expressed in human sperm, but their localizations differed. Inhibition of adenosine receptors significantly decreased cordycepin-induced sperm hyperactivation and the acrosome reaction. Molecular docking showed that cordycepin can bind to the four subtypes of adenosine receptors.ConclusionCordycepin may promote human sperm capacitation through adenosine receptor-mediated signaling pathways. These findings may be useful for assisted reproductive technology and animal breeding.

Optimizing food waste bioconversion with sodium selenite-enhanced Lucilia sericata maggots: a sustainable approach for chicken feed production and heavy metal mitigation.

Recycling food waste by feeding it to insects can result in the continuous production of high-quality animal feed protein and organic fertilizer. However, the bioconversion efficiency and safety of using insects as feed protein for animal breeding are important factors limiting the development of this technology. Therefore, we aimed to optimize the efficiency of bioconversion of food waste using Lucilia sericata maggot (LSM). Sodium selenite (SS) was used to improve the quality and safety of each trophic-level organism. The results showed that an SS concentration of 15mgkg-1 w.w. in the food waste culture substrate (SS15), the yield and quality of the obtained LSMs were optimal. The total selenium (Se) content of LSMs was 82.4 ± 1.16mgkg-1 d.w., and non-inorganic Se accounted for 96.4% ± 2.01% of the total Se content. Additionally, the conversion efficiency of food waste was 18.7% higher than that in the control group (p < 0.05). When SS15 was used to raise maggots as a protein substitute for fish meal (commercial feed), the weight of the chickens and the crude protein content were 1.09-1.26times and 1.09-1.13times, respectively (p < 0.05), in comparison with the corresponding findings obtained with the use of ordinary maggots and commercial feed. In this group, glutathione peroxidase, superoxide dismutase, catalase, and immunoglobulin A and G activities were significantly higher than those obtained with the other feeds (p < 0.05). During this cyclic utilization process, the total Se content in chickens (0.31 ± 0.05mgkg-1 w.w. in the breast, 0.19 ± 0.01mgkg-1 w.w. in the leg, and 0.57 ± 0.01mgkg-1 w.w. in the liver) significantly increased (p < 0.05). Meanwhile, the Cu and Zn contents in the LSMs and chickens increased, whereas cadmium, lead, chromium, and nickel absorption was inhibited (p < 0.05). Health risk assessment based on the levels of Se and heavy metals showed that Se-enriched chickens produced using this method can be safely consumed.

Meta-Analysis on Farmers’ Adoption of Agricultural Technologies in East Africa: Evidence from Chinese Agricultural Technology Demonstration Centers

Farmers’ low agricultural productivity in East African countries is attributed to among other factors, the low application of modern agricultural technologies. Using meta-analysis this study intended to examine the determinants of adoption of agricultural technologies in East African countries recipients of Chinese Agricultural Technology Demonstration Centers (ATDCs). A comprehensive review employed to gather 22 studies addressing the determinants of adoption of agricultural technologies such as improved varieties, agricultural mechanization, soil conservation, and animal breeding from Ethiopia, Tanzania, Uganda, and Rwanda. The collected data were analyzed using STATA 17 software. The study used a random-effect model to estimate the determinants of agricultural technologies adoption. The findings demonstrated that access to credit, age, education, farming experience, farmer group membership, household size, and off-farm income have a significant influence on farmers ‘adoption of improved varieties. Age, farm size, and education have a significant influence on the adoption of agricultural mechanization. Soil conservation practices are influenced by age, household size, and sex. Moreover, age, education, extension services, and farming experience have a significant impact on the adoption of animal breeding. It is recommended that East African governments, policymakers, and agricultural practitioners to focus on these common variables when planning for the intervention of new agricultural technologies.

Antibiotic-resistant genes derived from commercial organic fertilizers are transported to balconies of residential buildings by express delivery.

The rise in antibiotic-resistant genes (ARGs) has recently become a pressing issue, with livestock manure identified as a significant source of these genes. Yet, the distribution of fertilizers derived from livestock manure sold online, potentially containing high levels of ARGs and antibiotic-resistant bacteria (ARB), is often not considered. Our study involved a random survey of commercial organic fertilizers available on online marketplaces, focusing on 13 common ARGs and 2 integrons (intI1, intI2). We found significant ARGs linked to sulfonamides, macrolides, and tetracycline in the 20 fertilizer samples we tested. The gene copy numbers for ermC, sul2, and tetL were exceptionally high, reaching up to 1011 copies per gram of fertilizer in specific samples. Additionally, 18 out of 20 samples contained the critical β-lactam resistance genes blaTEM and blaKPC, with gene copy numbers up to 1010 copies/g. Integrons, intI1, and intI2 were present in all samples, with abundances ranging from 103 to 1010copies/g. We categorized the 20 samples into three types for further analysis: poultry manure, livestock manure, and earthworm manure. Our findings indicated a high presence of ARGs in poultry manure compared to a lower occurrence in earthworm manure. The study also showed a strong correlation between integrons and specific ARGs. This research underscores the potential risk of commercial organic fertilizers as a pathway for spreading ARGs from the animal breeding environment to human settings through express transportation.

Enhancing of Rabbit Sperm Cryopreservation with Antioxidants Mito-Tempo and Berberine.

Cryopreservation plays a critical role in animal breeding and the conservation of endangered species, but it often compromises sperm characteristics such as morphology, motility, and viability due to oxidative stress. This study explores the antioxidative effect of Mito-Tempo (MT) and Berberine (BER) to enhance post-thaw sperm quality in rabbits. Pooled rabbit sperm samples were supplemented with different concentrations (0.0, 0.5, 5, 10, 50 µmol/L) of MT and BER. Sperm motility was evaluated using computer-assisted semen analysis, while viability, apoptosis, reactive oxygen species (ROS) levels, acrosome integrity, and mitochondrial function were assessed through flow cytometry. The results revealed that MT at 5 and 10 µmol/L and BER at 10 µmol/L significantly improved total and progressive motility, mitochondrial activity, and sperm viability compared to the control group. Furthermore, 10 µmol/L BER enhanced acrosome integrity, while both 5 µmol/L MT and 10 µmol/L BER effectively reduced ROS levels and apoptosis. This study is the first to demonstrate the protective effects of MT and BER on rabbit sperm during cryopreservation. By mitigating oxidative stress and reducing apoptosis, these antioxidants markedly improved post-thaw sperm quality, positioning MT and BER as promising agents for improving sperm cryosurvival.

Genetic variation in surface temperature measured using infra-red thermography and genetic associations with production traits in grazing dairy cattle

ABSTRACT Increasing global temperatures and the incidence of extreme weather conditions will result in heat stress becoming a greater issue in production animals. Genetic selection and breeding for heat-tolerant animals have been promoted as a possible mitigation strategy in dairy cattle. The objectives of this study were to obtain in-field skin temperature measurements of the eye, muzzle and udder using infra-red thermography to examine the genetic variation in skin temperature within cows of a dairy herd and to estimate the genetic correlations between skin temperature and production traits. Thermal images and herd test records were obtained for the dairy herd at Massey University’s dairy farm 1. Estimates of (co)variances were obtained using the JWAS program with univariate and bivariate animal models. The heritability estimates for the eye, muzzle and udder temperature were low to moderate at 0.20, 0.24 and 0.39, respectively. All genetic correlations between production and temperature traits were positive except for eye temperature with milk yield and protein yield which was negative and weak. These results indicate that it may be possible to select for a greater skin temperature, however, these results need to be validated using a larger sample size.

Influence of different concentrations of milk urea nitrogen on the reproductive performance of Holstein cows.

The purpose of this study was to assess how various MUN levels affected the reproductive performance traits of Iranian Holsteins. The dataset used in this study included reproduction performance records for 16,000 Holstein cows and was gathered by the Animal Breeding Center and Promotion of Animal Products of Iran on 30 large dairy herds during 2018-2021. The MUN concentrations were grouped into four classes: [Formula: see text] mg/dL (MUN1), [Formula: see text] mg/dL (MUN2), [Formula: see text] mg/dL (MUN3), and [Formula: see text] mg/dL (MUN4). The study took into account various reproductive and fertility traits, such as the number of inseminations per conception (NINS), the percentage of pregnant cows till 120 days in milk (PP120), the calving interval (CI), the days open (DO), the days from calving to the first service (DCFS), the first service conception rate (FSCR), and the abortion rate (ABR). The impact of MUN levels on the incidence of abortion and non-pregnancy in dairy cows was investigated using logistic regression models. Also, to evaluate the effect of MUN concentrations on reproduction traits, a generalized linear model was used. The MUN2 group had the greatest odds of non-pregnancy (P < 0.05; OR = 2.81; MUN2 vs. MUN1). Also, the MUN4 group had the greatest odds of abortion (P < 0.01, OR = 3.36; MUN4 vs. MUN1). The MUN2 and MUN4 groups had the greatest (51.91%) and the lowest (34.32%) FSCR, respectively. MUN classes had a significant influence on DO (P < 0.05), and MUN4 had the largest value (145.44 days). The results indicated the negative association between MUN with reproduction and fertility in Iranian Holsteins.

Reproductive Biotechnology Tools as a Game Changer for the Dairy Sector: The Case of Sexed Semen and Estrus Synchronization to Produce Seedstock Dairy Heifers

Human curiosity about the sexual orientation of living things has a long history. For thousands of years, livestock owners wanted to find a suitable way to predict the sex of the progeny to be born for their herds on their farm. Thanks to the development of semen sexing technology, animal breeding has undergone a revolution, which allows farmers to control the sex of their offspring. Sexed semen enhances overall productivity and also assists farmers in meeting the rising demand for high-quality dairy animals by enabling them to selectively generate seedstock female calves. The technology is a one-stop solution to enhance breed improvement especially in a country like Ethiopia where 97 percent of the cattle population is indigenous, which is not selected for milk production and results in undernourishment for animal source origin diet, including milk and meat. The benefits of using sexed semen include sex selection, improved genetic selection, enhanced breeding effectiveness, better control over herd dynamics, greater financial gains, environmental sustainability, and improved animal welfare. Hence, with the finding of this study, an overall result of a 98% response rate 95% female skewness, and 79% conception rate was recorded after being inseminated with sexed semen. The finding of the response rate is closer to the results reported by another researcher, while the average conception rate is comparatively higher. This could be due to careful animal selection, the use of fertile quality semen, proper heat detection, and inseminating at an optimum window of time. In general, from the piece of this study, it is possible to foresee and conclude that the adoption and application of sexed semen technology is a groundbreaking and game-changer technology for the dairy industry in a country like Ethiopia, which overcomes the limitations of improved crossbred dairy cattle, replacement heifers, and high milk prices on the one hand, a shortage of grazing land, ...