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PubMed1977

Behavioral research in breeding colonies of Old World monkeys.

The existence of an active behavioral research program using animals in primate breeding colonies was considered to be not only a compatable multiple use of animals, but a way of materially improving the management and efficiency of the breeding colonies. In colonies of monkeys specifically established for behavioral research programs directed at the examination of social relationships, incidental breeding resulted in levels of reproductive success equivalent to or greater than that normally experienced in colonies devoted entirely to breeding. Behavioral research revealed patterns of seasonality, fostering, kidnapping, and infant care which would otherwise have escaped notice and which would significantly influence culling and management choices in a breeding colony. Many young males and certain low ranking adult males actively contributed to reproduction. Females born and reared in the colonies were the most productive, exceeding wild born or other introduced females in reproductive efficiency. Specific recommendations for establishing, expanding and culling of nonhuman primate breeding colonies were derived from the behavioral research.

Animals↗

PubMed1975

Histochemical studies on the mucosubstances in the ovotestis of a hermaphrodite land pulmonate Semperula maculata in seasonal breeding-aestivation cycle.

With a view to augment the cytochemical localization characterization and, probable functional significance of mucosubstances in the ovotestis in the reproductive physiology of land pulmonates, the mucosubstances were investigated in the ovotestis of a land snail, Semperula maculata (Stylommatophora) in the seasonal breeding-aestivation cycle. Widely accepted, recent and well-established histochemical techniques were emoloyed. The results showed that the cells in the germinal epithelium of the follicular wall, were endowed with a capacity of synthesis of neutral muco-substances. They also contained glycogen. The nurse cells contained neutral mucosubstances and glycogen in them, while maturing ovum contained hyaluronic acid and protein. Among all the male germ cell stages, only matured sperms showed sialoglycoprotein in their heads and glycogen in the tails. The seasonal variations in the mucosubstances showed that the synthesis of the mucosubstances in the male germ cells of the ovotestis was initiated at the end of the breeding season and attained a maximum in the post-breeding season. Most strikingly the presence of the sperm in the follicular cavity was a permanent feature throughout the seasonal breeding-aestivation cycle of the snails. The synthesis of the mucosubstances in the ovum and the nurse cells was initiated somewhat earlier in the post-breeding season and attained a peak prior to the active breeding season. The importance of the mucosubstances synthesised by the different cells of the ovotestis, is discussed with reference to the reproductive physiology of the snails.

Animals↗

PubMed1978

Problems of bovine leucosis control and prophylaxis in industrial breeding conditions.

Industrial cattle-breeding in Bulgaria is characterized by large cattle-breeding complexes holding 500, 1,000 or 2,000 dairy cows; farms specialized in rearing calves for breeding purposes, and calves fattening units holding 2,000, 5,000 or 10,000 animals. A specific technology has been introduced for management purposes. This high concentration and specialization creates specific organisational problems for antiepizootic control measures. Bovine leucosis has been brought from abroad by imported breedings animals. A complex system for leucosis prophylaxis and control is obligatorily implemented. It is supervized and financed by the state. Particular care is taken of ensuring protective measures for import breeding animals. The infected farms are put under strict quarantine. The animals which show a positive reaction during complex diagnostic tests are slaughtered and the meat is used after heat-processing. The milk is heat-processed too and sent for further utilization. Calves born in infected farms are not fit for breeding purposes but for fattening only.

Animals↗

PubMed2025

Molecular breeding of tomato: Advances and challenges.

The modern cultivated tomato (Solanum lycopersicum) was domesticated from Solanum pimpinellifolium native to the Andes Mountains of South America through a "two-step domestication" process. It was introduced to Europe in the 16th century and later widely cultivated worldwide. Since the late 19th century, breeders, guided by modern genetics, breeding science, and statistical theory, have improved tomatoes into an important fruit and vegetable crop that serves both fresh consumption and processing needs, satisfying diverse consumer demands. Over the past three decades, advancements in modern crop molecular breeding technologies, represented by molecular marker technology, genome sequencing, and genome editing, have significantly transformed tomato breeding paradigms. This article reviews the research progress in the field of tomato molecular breeding, encompassing genome sequencing of germplasm resources, the identification of functional genes for agronomic traits, and the development of key molecular breeding technologies. Based on these advancements, we also discuss the major challenges and perspectives in this field.

Solanum lycopersicum↗

PubMed2026

Effect of founder breeds on genotype imputation accuracy in Canchim cattle.

UNLABELLED: Genotype imputation is a technique used to infer unobserved genotypes based on reference panels, allowing increased marker density and cost-effective optimization for genomic selection. This study aimed to evaluate whether the inclusion of genotypes from the founder breeds Nelore (NE) and Charolais (CH) improves the imputation accuracy in the composite beef cattle breed Canchim (CA). The populations studied consisted of 804 NE, 897 CH, and 392 CA animals, all genotyped using high-density panels (777,962 SNP – single nucleotide polymorphisms). CA animals had their genotypes masked to simulate a medium-density panel (54,609 SNP). Fourteen imputation scenarios were evaluated, varying according to breed, sex, year of birth, and lineage. Imputation accuracy was determined based on the percentage of correctly imputed genotypes (PERC) and the squared Pearson’s correlation between observed and imputed genotypes (R2). PERC values ranged from 66.52% to 97.39% and R² from 0.6352 to 0.9780. The scenarios that included NE, CH, and CA (males or animals born before 2004) as the reference population for imputing CA females or CA animals born after 2004 showed the highest imputation accuracies. Therefore, the use of founder breeds in the reference population improves the accuracy of genotype imputation in CA cattle. The results indicate that a multibreed reference population, incorporating founder breeds, could provide a more robust and informative genetic basis for imputing composite cattle. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at https://doi.org/10.1007/s13353-026-01060-z.

Animal breeding↗

PubMed1979

[Some parameters in reproduction of a Maroccain sheep breed (race d'Man) (author's transl)].

The importance of the sheep in Marocco was shown with help of statistical data. As there exist very few scientific work on sheep reproduction in this country, we began to work on local breeds with the race d'Man. The breed is asaisonal and is able to lamb 2 times within 13 months, with mostly 2 or more youngs (1,8 lambs per partum). The delay of gestation was found with 150 days, the duration of a cycle 17 days. The libido shown by the rams is violent. They easily accepted an other male as phantome for the collection of sperm with the easily accepted artificial vagina. The gonads are ovoid formed and are early developed. Remarkable is the tail of the epididymis which is covered in a pocketlike formed structure of the distal scrotum. Its volume is remarkable. Concerning the characteristics of the sperm there is no difference with other breeds. Therefore the conclusion seems reasonable that this apparent development of the epididmymis tail is an organ for thermoregulation for the sperm as the breeds origin are the oasis of the Sahara. The early onset of puberty as well as the violent sexual interest and the high rate of reproduction and asaisonal behavior could be a reference to a "primitive breed".

Animals↗

PubMed1977

Characterization of extract of dog hair and dandruff from six different dog breeds by quantitative immunoelectrophoresis. Identification of allergens by crossed radioimmunoelectrophoresis (CRIE).

An extract of mixed dog hair and dandruff from six different dog breeds (alsatian, boxer, collie, poodle, and long-haired and short-haired dachshund) was obtained by mild extraction, centrifugation, dialysis and freeze-drying. Extract of hair and dandruff from the individual dog breeds was obtained in the same way, but the material was not freeze-dried. Examination and characterization of the mixed extract by means of crossed immunoelectrophoresis revealed a precipitation pattern composed of 25 antigens, some of which were mutually partially identical, and a high content of dog serum proteins was found. Quantitative and qualitative differences between the individual dog breeds were demonstrated. Partial identity of the antigens of the mixed extract with antigens of serum, antigens of extracts of hair and dandruff from cat, cow, horse and guinea pig, and antigens from extract of house dust was also observed. By means of crossed radioimmunoelectrophoresis, using sera from 21 patients who were RAST-positive to dog hair and dandruff extract, the specific IgE-binding to antigens of the mixed extract was examined. On the basis of these results major and minor allergens were identified. Dog albumin was found to be a very important major allergen, but alpha1-antitrypsin and gamma-globulin were also identified. Furthermore, four non-serum proteins were shown to be allergens. No breed-specific allergens could be identified in the extracts from the individual dog breeds.

Adult↗

PubMed2026

Dynamics of Antibiotic Resistance Gene Profiles in Captive Forest Musk Deer (Moschus berezovskii) Along a Breeding Duration Gradient.

BACKGROUND: To conserve wild populations and ensure a sustainable supply of musk, China initiated the captive breeding of forest musk deer. The temporal dynamics of gut antibiotic resistance gene (ARG) profiles in captive forest musk deer along a breeding duration gradient remain poorly characterized. METHODS: In this study, we employed metagenomic sequencing to systematically characterize the profiles and potential mobility of ARGs. Samples were divided into short-term, medium-term and long-term groups according to breeding durations. RESULTS: A total of 331 ARG subtypes and 71 mobile genetic element (MGE) subtypes were annotated across all samples. ARG Shannon diversity differed overall across groups (Kruskal-Wallis, p = 0.03); Bonferroni-adjusted Dunn's test showed no significant pairwise differences. PCoA (Bray-Curtis) demonstrated distinct separation of the ST group (p = 0.002), and shared core ARG subtypes gradually increased with extended breeding years. A strong positive correlation between ARG and MGE abundances was identified (r = 0.85, p = 0.0001). In total, 63 contigs carrying co-localized ARG-MGE complexes were recovered. The ST group contained the highest proportion of such contigs. The ST group displayed tight physical ARG-MGE linkage within 1-3 kb genomic intervals. CONCLUSIONS: Our results reveal that breeding duration is associated with the gut ARG characteristics of captive forest musk deer. Short-term captivity has higher ARG-MGE co-localization, suggesting a higher possibility of mobilization.

One Health↗

PubMed2026

Engineering cold stress resilience in capsicum annuum through functional genomics and precision breeding.

This review synthesizes the molecular mechanisms of cold tolerance in pepper, integrating multi-omics data,genome editing, and precision breeding strategies to accelerate the development of cold-resilient cultivars. Cold stress is a significant environmental factor that affects the growth, productivity, and fruit quality of Capsicum annuum by impairing membrane integrity photosynthesis and cellular redox homeostasis. Although pepper has several endogenous cold-responsive regulators such as CaNAC035 and CabHLH035, along with antioxidant defense systems, its cold tolerance remains limited due to low transcriptional activation of key regulators, functional redundancy among cold-responsive genes, and the polygenicity of cold tolerance. These complexities, combined with low genetic diversity and linkage drag, have hindered the improvement of cold-resistant cultivars through conventional breeding. This review brings together the recent progress in understanding the molecular mechanisms of cold stress perception, signal transduction, transcriptional regulation, metabolic reprogramming, and phytohormone interactions in pepper. Precision Breeding 2.0 is a new innovation that combines the integration of multi-omics-based target identification with next-generation genome-editing techniques, allowing precise and multiplex engineering of complex and interconnected regulatory networks instead of single genes. We cover new approaches such as engineering the DREB/CBF pathway, allele-specific editing and targeted disruption of negative regulators to enhance the pathway(s) involved in cold response. Moreover, we propose a roadmap for integration of transcriptomics, proteomics, metabolomics, high-throughput phenomics, and speed breeding to accelerate the identification, validation, and deployment of superior alleles to boost cold tolerance. This review provides a foundation for developing climate-resilient pepper cultivars by connecting functional genomics with precision genome engineering approaches to maintain productivity under variable environmental conditions.

Capsicum↗

PubMed2026

Translating Flood-Tolerance Biology into Breeding: A 5D Framework for Next-Generation Rice Varieties.

Flooding is among the most devastating abiotic stresses limiting rice productivity. Although SUB1A introgression conferred submergence tolerance in several mega-varieties, this single-gene approach is insufficient for the diverse flood types-flash floods, stagnant floods, anaerobic germination, and deepwater inundation-progressively intensifying with climate change. Here, we review the physiological mechanisms and genetic architecture underlying tolerance to each flood type, emphasizing the dual role of reactive oxygen species (ROS) in signalling and damage, the management of elemental toxicities (Fe2+, Mn2+) under altered soil redox, and lessons from wetland species and lowland rice. We then examine why marker-assisted selection has failed for polygenic, multi-stress tolerance and identify persistent breeding bottlenecks. Building on this biological foundation, we outline an integrated 5D framework (Demand, Discovery, Design, Development, Deployment) that links gene-bank diversity, multi-omics discovery, predictive breeding and on-farm validation through continuous feedback. We discuss how connected breeding, the transition-from-trait-to-environment (TTE) strategy, and speed breeding can accelerate genetic gain, and we close with research priorities centred on the biology of multi-flood tolerance to develop climate-resilient rice.

5D breeding framework↗

PubMed2026

Genomic analysis of breed composition and population structure in Montana composite cattle.

The Montana composite was developed in Brazil from crosses between Bos indicus and Bos taurus and structured into four biological types: Zebu (N), adapted taurine (A), British taurine (B), and continental taurine (C). This study aimed to characterize the genetic diversity and population structure of the Montana composite using genomic data through principal component analysis (PCA), admixture analysis, and Wright's FST statistic. The PCA revealed a clear separation between Bos indicus and Bos taurus groups, with Montana animals distributed in an intermediate position. The first two principal components explained 69.48% and 3.45% of the total variation, respectively. Supervised admixture estimates indicated a predominance of taurine contribution, with type A accounting for 34.47%, 52.64%, and 51.71% at K = 4, 9, and 11, respectively. Increasing the ancestry resolution refined the contribution of individual founder breeds without changing the overall predominance of taurine ancestry. Comparisons between breed proportions obtained from pedigree and genomic data revealed significant differences, for most biological types and ancestry models (P < 0.001), indicating that realized breed composition deviates from theoretical expectations. Estimates of genetic differentiation confirmed greater divergence between Zebu and taurine groups, as well as reduced distances among populations sharing common ancestry. Specific relationships were identified between the composite and some of its founder breeds, particularly Belmont Red, Senepol, and Tuli. Overall, the results demonstrate that the Montana composite has a complex genomic structure, with genomic ancestry varying according to the resolution adopted and differing from pedigree-based expectations.

Animals↗

PubMed2026

Translating functional molecular knowledge into crop-breeding success.

Historical plant breeding, which optimizes phenotypes through selective crossing guided by phenotypic evaluation and molecular markers, is limited by evolutionary constraints that hinder rapid crop improvement. A new paradigm, precision breeding, circumvents these limitations by targeting genetic variants through functional molecular knowledge. To generate this knowledge at scale, sequence-based deep learning leverages high-quality genome sequence data to predict variant effects at base-pair resolution. When linked to agronomically important traits, these predictions enable breeders to prioritize variants for precision selection or editing. Although it is still in the early stages of development, we foresee three key applications for this approach: introgressing genes from distant breeding pools, purging deleterious mutations and designing new plant ideotypes. Looking ahead, refined computational models will facilitate targeted editing and the systematic redesign of complex physiological processes to address emerging breeding goals under shifting environmental conditions.

Crops, Agricultural↗

PubMed1978

Pathophysiological differences between paired and communal breeding of male and female Sprague-Dawley rats.

Sexually mature, male and female Sprague-Dawley rats were housed in large communal breeding cages or in smaller paired breeding cages. Virgin control rats of the same age were housed similarly but segregated by sex. Breeders became obese, developed a fatty liver, and showed elevated levels of triglycerides, free fatty acids, and cholesterol. Breeders had high blood pressure, enlarged hearts, hyperglycemia, and islet beta cell degranulation. Serum enzymes, creatine phosphokinase, serum glutamic oxalo-pyruvic transaminase, serum glutamic pyruvic transaminase, lactate dehydrogenase, and blood urea nitrogen levels were elevated in breeder rats. The adrenal glands of male breeders appeared hyperactive; the adrenal glands of female breeders were thrombosed and appeared to be hypoactive. Male breeder rats developed microscopic aortic lesions only; female breeders developed advanced calcific aortic sclerosis. Male breeders kept in active stud service manifested the most abnormal metabolic and pathophysiological changes. Female breeders developed similar pathophysiological changes after four pregnancies, irrespective of their paired or communal breeding environment. Virgin rats were normal regardless of housing conditions. Our findings suggest that repeated breeding in male and female rats causes resetting of the hypothalamic-pituitary-adrenal-gonadal axis. This may lead to disturbed hormonal and metabolic changes which culminate with the development of accelerated cardiovascular degenerative changes.

Adrenal Cortex↗

PubMed1978

Reproductive and social behavior of marmosets with special reference to captive breeding.

The field studies reviewed above raise some doubts about the laboratory concept of the extended family as the basic social unit of the Callithricidae. As Dawson [6] suggests, wild groups might more closely approximate artificial laboratory groups. They probably consist of a dominant, monogamous breeding pair, its dependent offspring and separate hierarchies of subdominant males and females who stay associated with the group for various lengths of time. Some of these subdominants might be offspring or relatives of the breeding pair. As the field studies show, these groups are more or less open to immigrants coming from other groups. They possibly tolerate transient relatives more easily and for longer periods of time than nonrelated individuals. In spite of the relative tolerance of wild groups towards strange conspecifics, it appears most practical to maintain laboratory breeders as families and remove the offspring after they have participated in the care of their younger siblings. In this way their reproductive capacities can be utilized as soon as their parental behavior has developed adequately. Moreover, possible losses caused by keeping nonrelated adults of the same sex together are avoided. As pointed out above, some species are very aggressive towards strange adult conspecifics and some seem to defend territories in the wild. It seems advisable therefore to house them in cages which provide a certain degree of isolation from neighboring groups. We have found this to be more important in S. fuscicollis than in C. jacchus, particularly in densely populated colony rooms. We therefore house our animals in cages which allow no visual contact with any other group, and by doing so have reduced the general level of excitement in the colony room. We believe that aggressive displays between groups are responsible for a large amount of redirected aggression between mates and for some of the abortions we have seen in our colony. Moreover, Rothe's [28, 29] observation that the parturient female withdraws from her group and gives birth in relative isolation should be taken into consideration when designing breeding cages. Although not all individuals of all species might show this behavior [see 32] it seems to be widespread enough to be an important factor in breeding efficiency and might figure in some of the infanticides observed by us and other authors.

Aggression↗

PubMed1977

Seasonal incidence of estrus and interestrous interval for bitches of seven breeds.

For 7 breeds of bitches (Toy Poodle, Cocker Spaniel, Basset Hound, Boston Terrier, German Shepherd Dog, Pekingese, and Beagle), estrous activity occurred in all seasons. Differences in seasonal incidence of estrus were not statistically significant when compared within the total group or within and between breeds. The German Shepherd Dog breed had the shortest interestrous interval (149 +/- 28.5 days), which was significantly different from that of the other breeds. Means interestrous interval in parous Beagle bitches was not significantly different from that in nonparous Beagle bitches. In Beagle bitches, the mean interval between fertile estrous periods was not significantly different from the mean interval between nonfertile estrous periods.

Animals↗

PubMed1979

Morphologic variations and aging in the atrioventricular conduction system of large breed dogs.

The microscopic anatomy of the atrioventricular node, bundle of His, both bundle branches and surrounding fibrous cardiac skeleton was studied in 40 large breed dogs of various ages. In the AV conduction system of all dogs over five years of age there was an increase of fibrous connective tissue, an infiltration of adipose tissue, loss of conduction fibers and focal fibrosis extending from the central fibrous body. Fibrosis was seen in the summit of the interventricular septum posterior to the AV node in dogs of all ages. Chondroid metaplasia was consistently observed in the central fibrous body and the root of the aorta in large breed dogs, including ten Doberman Pinschers of all ages. This metaplasia varied from a few chondroblasts and chondrocytes to mature chondrocytes with mineralization. Bone formation was seen in eight dogs. These changes appeared in close approximation to the cardiac conduction system above the bundle of His. No degenerative changes were seen in the AV bundle. Approximately one-half of the large breed dogs five years of age and older had thickened medial and intima proliferation in the small coronary arterioles supplying the AV node. The results of this study suggest that the presence of cartilage and bone in the central fibrous body is a normal occurrence in large breed dogs at all ages.

Aging↗

PubMed1979

Effect of breed-type on carcass weight and composition in sheep.

The relative rate of increase in the carcass and its tissues with increasing empty body weight (EBW) or carcass weight respectively, was studied in male sheep from the Dorset Horn (29), Hampshire (21) and Sudan Desert sheep (31). The rate at which the carcass, muscle and bone increased in weight was the same in all breeds but the Desert sheep deposited fat at a slower rate than the other 2 breeds. At an equally adjusted EBW the Desert sheep had lighter carcasses than the Dorset Horn or Hampshire sheep. Desert sheep had more bone than the other 2 breeds at an equally adjusted cold carcass weight or muscle plus bone weight. At an equally adjusted total carcass fat weight the Desert sheep had significant (P < 0.01) more intermuscular and internal fat but less subcutaneous fat than the other 2 breeds. Future improvement plans of the Desert sheep may be directed towards reducing bone and increasing muscle content of the carcass.

Adipose Tissue↗

PubMed2026

Rapid CRISPR-based bovine embryo sexing to streamline genotype-informed cattle breeding.

Cattle in vitro fertilisation and embryo transfer programmes increasingly rely on embryo-level selection to accelerate genetic gain, but current sexing and genotyping workflows can be costly, slow and logistically demanding. This study developed an efficient, low-resource workflow for bovine embryo sexing that combines whole genome amplification (WGA) with recombinase polymerase amplification-CRISPR-Cas12a (RPA-Cas12a). It also assessed whether the same WGA biopsy products could be used for downstream single nucleotide polymorphism (SNP) microarray genotyping. A one-tube RPA-Cas12a assay targeting the bovine Y-chromosome S4 repeat was developed for fluorescence and lateral flow assay (LFA) readouts. Analytical sensitivity was assessed using serially diluted bovine genomic DNA (gDNA), and breed robustness was tested using male and female gDNA from five major beef breeds and Holstein cattle. The workflow was then applied to WGA products from 22 bovine blastocyst biopsies, with sex calls validated against an established real-time PCR melt curve assay and 100K SNP microarray genotyping. The assay detected male bovine gDNA down to 100 pg using both fluorescence and LFA readouts, with no signal from female gDNA. Male-specific detection was consistent across all breeds tested. All WGA-RPA-Cas12a sex calls from blastocyst biopsies were concordant with real-time PCR and SNP microarray sex calls, and WGA biopsy products produced genome-wide SNP call rates above 85%. This workflow provides a practical approach for rapid bovine embryo sex triage and could reduce unnecessary cryopreservation and genotyping while improving the efficiency of genotype-informed cattle breeding programmes.

Bovine embryo↗