Invited review: Breeding and ethical perspectives on genetically modified and genome edited cattle

Revolutionizing cattle breeding: Gene editing advancements for enhancing economic traits

Beef and dairy products are rich in protein and amino acids, making them highly nutritious for human consumption. The increasing use of gene editing technology in agriculture has paved the way for genetic improvement in cattle breeding via the development of the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein) system. Gene sequences are artificially altered and employed in the pursuit of improving bovine breeding research through targeted knockout, knock-in, substitution, and mutation methods. This review offers a comprehensive analysis of the advancements in gene editing technology and its diverse applications in enhancing both quantitative and qualitative traits across livestock. These applications encompass areas such as meat quality, milk quality, fertility, disease resistance, environmental adaptability, sex control, horn development, and coat colour. Furthermore, the review considers prospective ideas and insights that may be employed to refine breeding traits, enhance editing efficiency, and navigate the ethical considerations associated with these advancements. The review's focus on improving the quality of beef and milk is intended to enhance the economic viability of these products. Furthermore, it constitutes a valuable resource for scholars and researchers engaged in the fields of cattle genetic improvement and breeding.

A comprehensive review on the current status of CRISPR based clinical trials for rare diseases

A considerable fraction of population in the world suffers from rare diseases. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and its related Cas proteins offer a modern form of curative gene therapy for treating the rare diseases. Hereditary transthyretin amyloidosis, hereditary angioedema, duchenne muscular dystrophy and Rett syndrome are a few examples of such rare diseases. CRISPR/Cas9, for example, has been used in the treatment of β-thalassemia and sickle cell disease (Frangoul et al., 2021; Pavani et al., 2021) [1,2]. Neurological diseases such as Huntington's have also been focused in some studies involving CRISPR/Cas (Yang et al., 2017; Yan et al., 2023) [3,4]. Delivery of these biologicals via vector and non vector mediated methods depends on the type of target cells, characteristics of expression, time duration of expression, size of foreign genetic material etc. For instance, retroviruses find their applicability in case of ex vivo delivery in somatic cells due to their ability to integrate in the host genome. These have been successfully used in gene therapy involving X-SCID patients although, incidence of inappropriate activation has been reported. On the other hand, ex vivo gene therapy for β-thalassemia involved use of BB305 lentiviral vector for high level expression of CRISPR biological in HSCs. The efficacy and safety of these biologicals will decide their future application as efficient genome editing tools as they go forward in further stages of human clinical trials. This review focuses on CRISPR/Cas based therapies which are at various stages of clinical trials for treatment of rare diseases and the constraints and ethical issues associated with them.

Gene editing in animals: What does the public want to know and what information do stakeholder organizations provide?

Organizations involved with gene editing may engage with the public to share information and address concerns about the technology. It is unclear, however, if the information shared aligns with what people want to know. We aimed to understand what members of the public want to know about gene editing in animals by soliciting their questions through an open-ended survey question and comparing them with questions posed in Frequently Asked Question (FAQ) webpages developed by gene editing stakeholder organizations. Participants (338 USA residents) asked the most questions about gene editing in general and animal welfare. In contrast, FAQ webpages focused on regulations. The questions survey participants asked demonstrate a range of knowledge and interests. The discrepancy between survey participant questions and the information provided in the FAQ webpages suggests that gene editing stakeholders might engage in more meaningful public engagement by soliciting actual questions from the public and opening up opportunities for real dialogue.

Horizon scanning of potential environmental applications of terrestrial animals, fish, algae and microorganisms produced by genetic modification, including the use of new genomic techniques

With scientific progress and the development of new genomic techniques (NGTs), the spectrum of organisms modified for various purposes is rapidly expanding and includes a wide range of taxonomic groups. An improved understanding of which newly developed products may be introduced into the market and released into the environment in the near and more distant future is of particular interest for policymakers, regulatory authorities, and risk assessors. To address this information need, we conducted a horizon scanning (HS) of potential environmental applications in four groups of organisms: terrestrial animals (excluding insects and applications with gene drives), fish, algae and microorganisms. We applied a formal scoping review methodology comprising a structured search of the scientific literature followed by eligibility screening, complemented by a survey of grey literature, and regulatory websites and databases. In all four groups of organisms we identified a broad range of potential applications in stages of basic as well as advanced research, and a limited number of applications which are on, or ready to be placed on, the market. Research on GM animals including fish is focused on farmed animals and primarily targets traits which increase performance, influence reproduction, or convey resistance against diseases. GM algae identified in the HS were all unicellular, with more than half of the articles concerning biofuel production. GM algae applications for use in the environment include biocontrol and bioremediation, which are also the main applications identified for GM microorganisms. From a risk assessor's perspective these potential applications entail a multitude of possible pathways to harm. The current limited level of experience and limited amount of available scientific information could constitute a significant challenge in the near future, for which risk assessors and competent authorities urgently need to prepare.

A review of the role of epigenetic studies for intramuscular fat deposition in beef cattle

Intramuscular fat (IMF) deposition profoundly influences meat quality and economic value in beef cattle production. Meanwhile, contemporary developments in epigenetics have opened new outlooks for understanding the molecular basics of IMF regulation, and it has become a key area of research for world scholars. Therefore, the aim of this paper was to provide insight and synthesis into the intricate relationship between epigenetic mechanisms and IMF deposition in beef cattle. The methodology involves a thorough analysis of existing literature, including pertinent books, academic journals, and online resources, to provide a comprehensive overview of the role of epigenetic studies in IMF deposition in beef cattle. This review summarizes the contemporary studies in epigenetic mechanisms in IMF regulation, high-resolution epigenomic mapping, single-cell epigenomics, multi-omics integration, epigenome editing approaches, longitudinal studies in cattle growth, environmental epigenetics, machine learning in epigenetics, ethical and regulatory considerations, and translation to industry practices from perspectives of IMF deposition in beef cattle. Moreover, this paper highlights DNA methylation, histone modifications, acetylation, phosphorylation, ubiquitylation, non-coding RNAs, DNA hydroxymethylation, epigenetic readers, writers, and erasers, chromatin immunoprecipitation followed by sequencing, whole genome bisulfite sequencing, epigenome-wide association studies, and their profound impact on the expression of crucial genes governing adipogenesis and lipid metabolism. Nutrition and stress also have significant influences on epigenetic modifications and IMF deposition. The key findings underscore the pivotal role of epigenetic studies in understanding and enhancing IMF deposition in beef cattle, with implications for precision livestock farming and ethical livestock management. In conclusion, this review highlights the crucial significance of epigenetic pathways and environmental factors in affecting IMF deposition in beef cattle, providing insightful information for improving the economics and meat quality of cattle production.

Perspectives in Genome-Editing Techniques for Livestock

Genome editing of farm animals has undeniable practical applications. It helps to improve production traits, enhances the economic value of livestock, and increases disease resistance. Gene-modified animals are also used for biomedical research and drug production and demonstrate the potential to be used as xenograft donors for humans. The recent discovery of site-specific nucleases that allow precision genome editing of a single-cell embryo (or embryonic stem cells) and the development of new embryological delivery manipulations have revolutionized the transgenesis field. These relatively new approaches have already proven to be efficient and reliable for genome engineering and have wide potential for use in agriculture. A number of advanced methodologies have been tested in laboratory models and might be considered for application in livestock animals. At the same time, these methods must meet the requirements of safety, efficiency and availability of their application for a wide range of farm animals. This review aims at covering a brief history of livestock animal genome engineering and outlines possible future directions to design optimal and cost-effective tools for transgenesis in farm species.

Methods of crop improvement and applications towards fortifying food security

Agriculture has supported human life from the beginning of civilization, despite a plethora of biotic (pests, pathogens) and abiotic (drought, cold) stressors being exerted on the global food demand. In the past 50 years, the enhanced understanding of cellular and molecular mechanisms in plants has led to novel innovations in biotechnology, resulting in the introduction of desired genes/traits through plant genetic engineering. Targeted genome editing technologies such as Zinc-Finger Nucleases (ZFNs), Transcription Activator-Like Effector Nucleases (TALENs), and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) have emerged as powerful tools for crop improvement. This new CRISPR technology is proving to be an efficient and straightforward process with low cost. It possesses applicability across most plant species, targets multiple genes, and is being used to engineer plant metabolic pathways to create resistance to pathogens and abiotic stressors. These novel genome editing (GE) technologies are poised to meet the UN's sustainable development goals of "zero hunger" and "good human health and wellbeing." These technologies could be more efficient in developing transgenic crops and aid in speeding up the regulatory approvals and risk assessments conducted by the US Departments of Agriculture (USDA), Food and Drug Administration (FDA), and Environmental Protection Agency (EPA).

Genomics in animal breeding from the perspectives of matrices and molecules

BACKGROUND

This paper describes genomics from two perspectives that are in use in animal breeding and genetics: a statistical perspective concentrating on models for estimating breeding values, and a sequence perspective concentrating on the function of DNA molecules.

MAIN BODY

This paper reviews the development of genomics in animal breeding and speculates on its future from these two perspectives. From the statistical perspective, genomic data are large sets of markers of ancestry; animal breeding makes use of them while remaining agnostic about their function. From the sequence perspective, genomic data are a source of causative variants; what animal breeding needs is to identify and make use of them.

CONCLUSION

The statistical perspective, in the form of genomic selection, is the more applicable in contemporary breeding. Animal genomics researchers using from the sequence perspective are still working towards this the isolation of causative variants, equipped with new technologies but continuing a decades-long line of research.

Application of the transgenic pig model in biomedical research: A review

The large animal model has gradually become an essential part of preclinical research studies, relating to exploring the disease pathological mechanism, genic function, pharmacy, and other subjects. Although the mouse model has already been widely accepted in clinical experiments, the need for finding an animal model with high similarity compared with a human model is urgent due to the different body functions and systems between mice and humans. The pig is an optimal choice for replacement. Therefore, enhancing the production of pigs used for models is an important part of the large animal model as well. Transgenic pigs show superiority in pig model creation because of the progress in genetic engineering. Successful cases of transgenic pig models occur in the clinical field of metabolic diseases, neurodegenerative diseases, and genetic diseases. In addition, the choice of pig breed influences the effort and efficiency of reproduction, and the mini pig has relative obvious advantages in pig model production. Indeed, pig models in these diseases provide great value in studies of their causes and treatments, especially at the genetic level. This review briefly outlines the method used to create transgenic pigs and species of producing transgenic pigs and provides an overview of their applications on different diseases and limitations for present pig model developments.

Emerging Roles of Noncoding RNAs in Bovine Mastitis Diseases

Non-coding RNAs (ncRNAs) are an abundant class of RNA with varying nucleotide lengths. They have been shown to have great potential in eutherians/human disease diagnosis and treatments and are now gaining more importance for the improvement of diseases in livestock. To date, thousands of ncRNAs have been discovered in the bovine genome and the continuous advancement in deep sequencing technologies and various bioinformatics tools has enabled the elucidation of their roles in bovine health. Among farm animals' diseases, mastitis, a common inflammatory disease in cattle, has caused devastating economic losses to dairy farmers over the last few decades. Here, we summarize the biology of bovine mastitis and comprehensively discuss the roles of ncRNAs in different types of mastitis infection. Based on our findings and relevant literature, we highlighted various evidence of ncRNA roles in mastitis. Different approaches (in vivo versus in vitro) for exploring ncRNA roles in mastitis are emphasized. More particularly, the potential applications of emerging genome editing technologies, as well as integrated omics platforms for ncRNA studies and implications for mastitis are presented.

Gene-Edited Meat: Disentangling Consumers' Attitudes and Potential Purchase Behavior

Novel gene-editing (GE) technologies provide promising opportunities to increase livestock productivity and to tackle several global livestock production sustainability and food security challenges. However, these technologies, as with previous genetic modification technologies in food production, are very likely to generate social controversy and opposition toward their use in the meat industry. Here, we explored public attitudes and consumption predisposition toward gene-edited meat products and their potential added benefits to livestock farming. Our results show that societal perception currently comes as a package, where the use of gene-editing technology acts as an extrinsic cue of meat products quality, and is used to make a range of inferences about all quality facets at once. Although consumers with anti-GE attitudinal positions generally were not sensitive to price discounts or added benefits, added benefits increased the consumption predisposition of most moderate and pro-GE consumers, where benefits related to animal welfare had larger effects than those relating to the environment or human health issues.

Genetics Matters: Voyaging from the Past into the Future of Humanity and Sustainability

The understanding of how genetic information may be inherited through generations was established by Gregor Mendel in the 1860s when he developed the fundamental principles of inheritance. The science of genetics, however, began to flourish only during the mid-1940s when DNA was identified as the carrier of genetic information. The world has since then witnessed rapid development of genetic technologies, with the latest being genome-editing tools, which have revolutionized fields from medicine to agriculture. This review walks through the historical timeline of genetics research and deliberates how this discipline might furnish a sustainable future for humanity.

From Genotype to Phenotype: Polygenic Prediction of Complex Human Traits

Decoding the genome confers the capability to predict characteristics of the organism (phenotype) from DNA (genotype). We describe the present status and future prospects of genomic prediction of complex traits in humans. Some highly heritable complex phenotypes such as height and other quantitative traits can already be predicted with reasonable accuracy from DNA alone. For many diseases, including important common conditions such as coronary artery disease, breast cancer, type I and II diabetes, individuals with outlier polygenic scores (e.g., top few percent) have been shown to have 5 or even 10 times higher risk than average. Several psychiatric conditions such as schizophrenia and autism also fall into this category. We discuss related topics such as the genetic architecture of complex traits, sibling validation of polygenic scores, and applications to adult health, in vitro fertilization (embryo selection), and genetic engineering.

Ethics and animal reproductive technologies

This paper offers a framework to help animal scientists engage in critical thinking about their own practices. Its objective is to reinforce their ability to participate in debates and discussions about the ethics surrounding the use of modern animal reproductive technologies (ART). This will be achieved first by exploring some of the most important philosophical conceptualizations of animals in Western philosophy, which are shaping the way humans interact with them. Then, we will analyse whether modern ART constitute ethically significant innovations in comparison with more traditional animal breeding practices, or whether they stand in continuity with the latter. This will be followed by a review some of the most important ethical issues with modern ART, where human, animal welfare, environmental and socio-economic issues will be discussed.

Genome Editing Strategies to Protect Livestock from Viral Infections

The livestock industry is constantly threatened by viral disease outbreaks, including infections with zoonotic potential. While preventive vaccination is frequently applied, disease control and eradication also depend on strict biosecurity measures. Clustered regularly interspaced palindromic repeats (CRISPR) and associated proteins (Cas) have been repurposed as genome editors to induce targeted double-strand breaks at almost any location in the genome. Thus, CRISPR/Cas genome editors can also be utilized to generate disease-resistant or resilient livestock, develop vaccines, and further understand virus-host interactions. Genes of interest in animals and viruses can be targeted to understand their functions during infection. Furthermore, transgenic animals expressing CRISPR/Cas can be generated to target the viral genome upon infection. Genetically modified livestock can thereby reduce disease outbreaks and decrease zoonotic threats.

Applications of CRISPR-Cas9 as an Advanced Genome Editing System in Life Sciences

Targeted nucleases are powerful genomic tools to precisely change the target genome of living cells, controlling functional genes with high exactness. The clustered regularly interspaced short palindromic repeats associated protein 9 (CRISPR-Cas9) genome editing system has been identified as one of the most useful biological tools in genetic engineering that is taken from adaptive immune strategies for bacteria. In recent years, this system has made significant progress and it has been widely used in genome editing to create gene knock-ins, knock-outs, and point mutations. This paper summarizes the application of this system in various biological sciences, including medicine, plant science, and animal breeding.

Gene Editing for Improved Animal Welfare and Production Traits in Cattle: Will This Technology Be Embraced or Rejected by the Public?

Integrating technology into agricultural systems has gained considerable traction, particularly over the last half century. Agricultural systems that incorporate the public’s concerns regarding farm animal welfare are more likely to be socially accepted in the long term, a key but often forgotten component of sustainability. Gene editing is a tool that has received considerable attention in the last five years, given its potential capacity to improve farm animal health, welfare, and production efficiency. This study aimed to explore the attitudes of Brazilian citizens regarding the applications of gene editing in cattle that generate offspring without horns; are more resistant to heat; and have increased muscle tissue. Using a mixed-methods approach, we surveyed participants via face-to-face, using in-depth interviews (Study 1) and an online questionnaire containing closed-ended questions (Study 2). Overall, the acceptability of gene editing was low and in cases where support was given it was highly dependent on the type and purpose of the application proposed. Using gene editing to improve muscle tissue growth was viewed as less acceptable compared to using gene editing to reduce heat stress or to produce hornless cattle. Support declined when the application was perceived to harm animal welfare, to be profit motivated or to reinforce the status quo of intensive livestock systems. The acceptability of gene editing was reduced when perceptions of risks and benefits were viewed as unevenly or unfairly distributed among consumers, corporations, different types of farmers, and the animals. Interviewees did not consider gene editing a “natural” process, citing dissenting reasons such as the high degree of human interference and the acceleration of natural processes. Our findings raised several issues that may need to be addressed for gene editing to comply with the social pillar of sustainable agriculture.

Enhancing the Nutritional Value of Red Meat through Genetic and Feeding Strategies

Consumption of red meat contributes to the intake of many essential nutrients in the human diet including protein, essential fatty acids, and several vitamins and trace minerals, with high iron content, particularly in meats with high myoglobin content. Demand for red meat continues to increase worldwide, particularly in developing countries where food nutrient density is a concern. Dietary and genetic manipulation of livestock can influence the nutritional value of meat products, providing opportunities to enhance the nutritional value of meat. Studies have demonstrated that changes in livestock nutrition and breeding strategies can alter the nutritional value of red meat. Traditional breeding strategies, such as genetic selection, have influenced multiple carcass and meat quality attributes relevant to the nutritional value of meat including muscle and fat deposition. However, limited studies have combined both genetic and nutritional approaches. Future studies aiming to manipulate the composition of fresh meat should aim to balance potential impacts on product quality and consumer perception. Furthermore, the rapidly emerging fields of phenomics, nutrigenomics, and integrative approaches, such as livestock precision farming and systems biology, may help better understand the opportunities to improve the nutritional value of meat under both experimental and commercial conditions.

A Review of Recent Advances in 3D Bioprinting With an Eye on Future Regenerative Therapies in Veterinary Medicine

3D bioprinting is a rapidly evolving industry that has been utilized for a variety of biomedical applications. It differs from traditional 3D printing in that it utilizes bioinks comprised of cells and other biomaterials to allow for the generation of complex functional tissues. Bioprinting involves computational modeling, bioink preparation, bioink deposition, and subsequent maturation of printed products; it is an intricate process where bioink composition, bioprinting approach, and bioprinter type must be considered during construct development. This technology has already found success in human studies, where a variety of functional tissues have been generated for both in vitro and in vivo applications. Although the main driving force behind innovation in 3D bioprinting has been utility in human medicine, recent efforts investigating its veterinary application have begun to emerge. To date, 3D bioprinting has been utilized to create bone, cardiovascular, cartilage, corneal and neural constructs in animal species. Furthermore, the use of animal-derived cells and various animal models in human research have provided additional information regarding its capacity for veterinary translation. While these studies have produced some promising results, technological limitations as well as ethical and regulatory challenges have impeded clinical acceptance. This article reviews the current understanding of 3D bioprinting technology and its recent advancements with a focus on recent successes and future translation in veterinary medicine.

Genetic parameters for somatic cell count (SCC) and milk production traits of Guzerá cows using data normalized by different procedures

This study aimed to estimate the genetic parameters for somatic cell count (SCC) and the genetic association between SCC and milk production traits using two different methods of SCC normalization. The dataset contained information on 8870 lactation records of 6172 Guzerá dairy cows selected for dual-purpose from 95 herds. The lactation means of SCC were normalized in two ways: (a) SCC₁ = log₁₀ (SCC) and (b) SCC₂ = log₂ (SCC/100) + 3. Multivariate analyses were performed considering milk production traits over the course of 305 days of lactation. Estimates of the variance components and genetic parameters were carried out by the Bayesian inference method, applying Gibbs sampling. Single chains of 2,000,000 iterations were used, with sampling discards of the first 5000 chains and a sampling period of every 50 iterations. The deviation of information criteria (DIC) was used to evaluate the best transformation for standardization of the SCC data, comparing analysis 1 (milk production traits over 305 days and SCC₁) with analysis 2 (milk production traits over 305 days and SCC₂). According to the data structure of this study, SCC₁ normalization was the most efficient method and produced better estimates than normalization by the SCC₂ method. The heritability estimates for SCC were low regardless of the transformation method used, indicating a small possibility of expressive genetic gains from the direct selection of these traits. However, the repeatability indicated the potential for increasing heritability estimates if the effects of the permanent environment were reduced. The genetic correlations between the milk yield and SCC traits do not indicate the possibility of a correlated genetic gain from the direct selection of one trait. However, concomitant selection for milk production traits and SCC will likely not affect the individual response either.

Bioethical issues in genome editing by CRISPR-Cas9 technology

Genome editing technologies have led to fundamental changes in genetic science. Among them, CRISPR-Cas9 technology particularly stands out due to its advantages such as easy handling, high accuracy, and low cost. It has made a quick introduction in fields related to humans, animals, and the environment, while raising difficult questions, applications, concerns, and bioethical issues to be discussed. Most concerns stem from the use of CRISPR-Cas9 to genetically alter human germline cells and embryos (called germline genome editing). Germline genome editing leads to serial bioethical issues, such as the occurrence of undesirable changes in the genome, from whom and how informed consent is obtained, and the breeding of the human species (eugenics). However, the bioethical issues that CRISPR-Cas9 technology could cause in the environment, agriculture and livestock should also not be forgotten. In order for CRISPR-Cas9 to be used safely in all areas and to solve potential issues, worldwide legislation should be prepared, taking into account the opinions of both life and social scientists, policy makers, and all other stakeholders of the sectors, and CRISPR-Cas9 applications should be implemented according to such legislations. However, these controls should not restrict scientific freedom. Here, various applications of CRISPR-Cas9 technology, especially in medicine and agriculture, are described and ethical issues related to genome editing using CRISPR-Cas9 technology are discussed. The social and bioethical concerns in relation to human beings, other organisms, and the environment are addressed.

Production, chemical composition, and economic viability of Minas Frescal cheese from buffaloes supplemented with açai seed

We aimed to evaluate the chemical composition, production yield, and economic viability of Minas Frescal cheese produced with milk from buffaloes supplemented with açai seed as a substitute for corn meal. The experiment used five Murrah crossbred buffaloes with a mean body weight of 577 ± 20.4 kg, maintained under Megathyrsus maximus cv. Mombaça grazing in a 5 × 5 Latin square design. The treatments comprised four concentrate supplements, in which açai seed replaced corn meal at 0, 33, 66, and 100% substitution, and a control with no concentrate supplementation. Replacement of corn meal with açai seed in buffalo diet had no effect on chemical composition of produced cheese (P > 0.05) nor was there any difference in chemical composition between the control group and animals supplemented with concentrate (P > 0.05). The adjusted cheese yield (kg cheese/cow/day) demonstrated a quadratic pattern with maximum production at 33% açai seed substitution (P < 0.05). Hence, the profitability index (percentage of gross revenue) was greatest at this replacement level. In conclusion, 33% açai seed replacement of corn meal in the supplement of buffalo under a grazing regime improved the individual yield of Minas Frescal cheese without changing its chemical composition.

Palmitic acid-enriched fat supplementation alleviates negative production responses during early lactation of Holstein dairy cows

Effects of rumen-protected fat (RPF) on suppressing the negative performance responses in early lactation period of Holstein dairy cows were investigated. Three hundred multiparous Holstein cows (647 ± 16 kg bodyweight and 90 days in milk (DIM)) were randomly housed into three free-stall barns (100 cows per barn) and assigned to the treatments for 90 days, as follows: (1) control (CTL) diet without RPF; (2) calcium salt of palm fatty acids (CaFA) 30 g/kg DM, and (3) fractionated fatty acids of palm oil (FFA) 25 g/kg DM. Cows were fed total mixed ration containing 580 g of concentrate and 420 g of roughage per kilogram DM. Cows fed FFA exhibited a higher (P &lt; 0.05) DM intake and body condition score than did those fed CaFA or CTL diets respectively. Moreover, cows fed the FFA diet showed decreased (P &lt; 0.05) changes to bodyweight at 30 DIM and to body condition score at 60 DIM and increased digestibility of ether extract and neutral detergent fibre. Blood concentrations of triglycerides, cholesterol and glucose were higher (P &lt; 0.05) for cows fed FFA diet than for those fed the other diets, between 4 and 30 DIM, whereas concentrations of non-esterified fatty acids, β-hydroxybutyric acid and urine ketones were lower for cows fed RPF sources (P &lt; 0.05). Relative to CTL diet, CaFA and FFA diets increased (P &lt; 0.05) milk yield and milk fat content at 4–30 DIM. Feeding FFA improved feed efficiency by 8.9% (P = 0.006), between 31 and 60 DIM, compared with CaFA. Inclusion of a palmitic acid-enriched fat supplement in Holstein cow diet increased milk yield and fat content and mitigated the deleterious effects of metabolic disorders during the early lactation period.

Strategies for Sustainable Use of Indigenous Cattle Genetic Resources in Southern Africa

Indigenous cattle breeds are the most important livestock species in the Southern African Development Community (SADC) region owing to their role in human food, nutrition, income, and social security. Despite the role of these breeds in the household and national economies, they are currently underutilised, their productivity remains low, and populations are faced with extinction. In addition, there are insufficient measures taken to secure their present and future value. The current review highlights strategies for sustainable use of indigenous cattle genetic resources in the region, including the use of novel production and marketing practices, women and youth empowerment, and development of the appropriate capacity building, legislative, and policy structures. At present, the lack of coordination among the different stakeholders still poses a challenge to the implementation of these strategies. To this end, partnerships, collaboration, and stakeholders’ participation are recommended to effectively implement strategies for sustainable use of indigenous cattle breeds.

Is gene editing an acceptable alternative to castration in pigs?

Male piglets are commonly castrated to eliminate the risk of boar taint. Surgical castration is the commonly used procedure and is known to induce pain. Gene modification targeted at eliminating boar taint in male pigs has been proposed as a possible alternative to surgical castration. The aims of this study were to explore public acceptability of this biotechnology using a mixed methods approach. Quantitative data to assess acceptability of 570 participants from southern Brazil were analysed with multinomial logistic regression models and Spearman correlations; qualitative responses of the reasons provided in support of their position were coded into themes. Just over half of the participants (56%) considered gene modification of male pigs acceptable. Acceptability was lower among participants who grew up in an agricultural environment (ρ = 0.02), but was not influenced by sex, age, religion, urban or rural living, or level of education. Acceptability of gene modification of male pigs as an alternative to surgical castration was positively related to the perception of benefits (r = -0.56, ρ<0.0001) and negatively related to the participant’s perception of risks (r = -0.35, ρ<0.0001). Acceptability was not related to knowledge of basic concepts of genetic biotechnologies (r = 0.06, ρ<0.14), or to awareness of issues related to pig castration or boar taint (r = 0.03, ρ<0.44), both of which were low among participants. Participants that considered gene modification of pigs acceptable justified their position using arguments that it improved animal welfare. In contrast, those that were not in favour were generally opposed to genetic modification. Unforeseen downstream consequences of using genetic modification in this manner was a major concern raised by over 80% of participants. Our findings suggest that perceived animal welfare may encourage public support of gene editing of food animals. However, potential risks of the technology need to be addressed and conveyed to the public, as many participants requested clarification of such risks as a condition for support.

Regulation and safety considerations of somatic cell nuclear transfer-cloned farm animals and their offspring used for food production

This document discusses recent developments in cloning of husbandry animals through somatic cell nuclear transfer, particularly with a view on improvements in their efficacy. Commercial developments in North and South America, Australia-New Zealand, and China are noted. The regulations and safety aspects surrounding the use of clones and their offspring for the purpose of food production are discussed. It is generally considered that foods from offspring of clones are no different than similar foods from conventional animals, yet besides safety, also ethical and animal welfare considerations come into play at the policy level. The related topic of detection and traceability of clones is discussed, which covers both molecular and documentary methods.

The ethics of genome editing in non-human animals: a systematic review of reasons reported in the academic literature

In recent years, new genome editing technologies have emerged that can edit the genome of non-human animals with progressively increasing efficiency. Despite ongoing academic debate about the ethical implications of these technologies, no comprehensive overview of this debate exists. To address this gap in the literature, we conducted a systematic review of the reasons reported in the academic literature for and against the development and use of genome editing technologies in animals. Most included articles were written by academics from the biomedical or animal sciences. The reported reasons related to seven themes: human health, efficiency, risks and uncertainty, animal welfare, animal dignity, environmental considerations and public acceptability. Our findings illuminate several key considerations about the academic debate, including a low disciplinary diversity in the contributing academics, a scarcity of systematic comparisons of potential consequences of using these technologies, an underrepresentation of animal interests, and a disjunction between the public and academic debate on this topic. As such, this article can be considered a call for a broad range of academics to get increasingly involved in the discussion about genome editing, to incorporate animal interests and systematic comparisons, and to further discuss the aims and methods of public involvement. This article is part of a discussion meeting issue 'The ecology and evolution of prokaryotic CRISPR-Cas adaptive immune systems'.

Encapsulation of soybean meal with fats enriched in palmitic and stearic acids: effects on rumen-undegraded protein and in vitro intestinal digestibility

Fat coating of soybean meal (SBM) can reduce its protein degradability in the rumen, but the encapsulation of SBM with palmitic (PA) and stearic acids (SA) has not yet been investigated, despite both fatty acids are common energy sources in dairy cow diets. This study aimed to evaluate the effects of applying a novel method, using either 400 or 500 g fat/kg (treatments FL40 and FL50, respectively), which was enriched in PA and SA at different ratios (100:0, 75:25, 50:50, 25:75 and 0:100), on physical and chemical characteristics, ruminal degradability, solubility and in vitro intestinal protein digestibility (IVIPD) of the obtained products. Encapsulation of SBM in fat resulted in greater mean particle size and lower bulk density and protein solubility than unprotected SBM (USBM). Treatment FL50 resulted in increased (p < 0.01) rumen-undegraded protein (RUP) compared to USBM. There were no differences in RUP of SBM when different PA: SA ratios were used. The mean RUP content of treatments FL40 and FL50 (306 and 349 g/kg, respectively) was greater compared to USBM (262 g/kg, p < 0.05), but lower than that for a standard heat-treated SBM (431 g/kg). Values of IVIPD did not differ among SBM, heat-treated SBM and FL40 and FL50 samples, all being greater than 97.8%. In conclusion, encapsulation of SBM with fats enriched in PA and SA proved to be effective in reducing protein solubility and increasing RUP without depressing protein digestibility in the intestine. For validation of the method, in vivo research to investigate the effects of these products on the production of dairy cows is warranted.

Comparison of gene editing versus conventional breeding to introgress the POLLED allele into the US dairy cattle population

Disbudding and dehorning are commonly used cattle management practices to protect animals and humans from injury. They are unpleasant, costly processes subject to increased public scrutiny as an animal welfare issue. Horns are a recessively inherited trait, so one option to eliminate dehorning is to breed for polled (hornlessness). However, due to the low genetic merit and scarcity of polled dairy sires, this approach has not been widely adopted. In March 2018, only 3 Holstein and 0 Jersey active homozygous polled sires were registered with the National Association of Animal Breeders. Alternatively, gene editing to produce high-genetic-merit polled sires has been proposed. To further explore this concept, introgression of the POLLED allele into both the US Holstein and Jersey cattle populations via conventional breeding or gene editing (top 1% of bulls/year) was simulated for 3 polled mating schemes and compared with baseline selection on lifetime net merit (NM$) alone, over the course of 20 yr. Scenarios were replicated 10 times and the changes in HORNED allele frequency, inbreeding, genetic gain (NM$), and number of unique sires used were calculated. Gene editing decreased the frequency of the HORNED allele to <0.1 after 20 yr, which was as fast or faster than conventional breeding for both breeds. In the mating scheme that required the use of only existing homozygous polled sires, inbreeding reached 17% (Holstein) and 14% (Jersey), compared with less than 7% in the baseline scenarios. However, gene editing in the same mating scheme resulted in significantly less inbreeding, 9% (Holstein) and 8% (Jersey). Also, gene editing resulted in significantly higher NM$ after 20 yr compared with conventional breeding for both breeds. Additionally, the gene editing scenarios of both breeds used a significantly greater number of unique sires compared with either the conventional breeding or baseline scenarios. Overall, our simulations show that, given the current genetic merit of horned and polled dairy sires, the use of conventional breeding methods to decrease the frequency of the HORNED allele will increase inbreeding and slow genetic improvement. Furthermore, this study demonstrates how gene editing could be used to rapidly decrease the frequency of the HORNED allele in US dairy cattle populations while maintaining the rate of genetic gain, constraining inbreeding to acceptable levels, and simultaneously addressing an emerging animal welfare concern.

Ethics in animal breeding

Ethical breeding involves the use of healthy animals true to their species in behaviour and physical appearance, and when applicable, showing a sustainable performance. The concerns for the species/breed are essential parts of the breeding goals, including preservation of genetic resources within the species/breed, and the health and welfare of the individual animal. Ethical and welfare considerations were often not prioritized in developing new breeds of production or companion animals. As a result, animal breeding practices are increasingly becoming part of the debate on animal welfare. In companion animals, breeding for curiosity or "cuteness" may be a goal in itself, although dogs are also bred for utility. In production animals, breeding focus is on performance, i.e., quantitative entities and financial income, rather than physical appearance. For instance, dairy cows are bred to be larger and to have higher milk yields, sows and ewes to produce more offspring, and horses are designed for riding, racing, and companionship. Overbreeding in relation to current demand of horses, cats, and dogs raises welfare issues due to abandonment or killing of horses and millions of cats and dogs every year. There is variable regulation of health requirements for breeding animals in different countries of the world. In many countries, consumers are becoming increasingly aware of animal welfare issues such as negative effects of certain production traits in farm animals, leading to decreased demand for their meat at a time where increased food production is becoming crucial. Amidst these dilemmas are the veterinarians. This paper deals with issues connected to traditional breeding as well as some of the breeding technologies, and includes food safety, ethics, and animal welfare.

Correlating in vitro digestion viscosities and bioaccessible nutrients of milks containing enhanced protein concentration and normal or modified protein ratio to human trials

In vitro digestion of cereal with high protein milks reflects the appearance of in vivo biomarkers of starch and protein digestion.