Canopy Architectural Characteristics of Ten New Olive (Olea europaea L.) Genotypes and Their Potential for Cultivation in Super-High-Density Orchards.

In recent years, there has been growing interest in olive genotypes (Olea europaea L.) suitable for super-high-density (SHD > 1200 trees/hectare) orchards. To date, only a few cultivars are considered fitting for such cultivation system. In this study, the first results on the architectural characteristics of the canopy of ten new olive genotypes are presented. Their suitability for SHD orchards was evaluated and compared with the cultivar 'Arbequina', which is considered suitable for SHD olive orchards and, for this reason, was used as the control. Several canopy measurements were taken, and some architectural parameters, such as branching frequency, branching density, and branch diameter/stem diameter ratio were calculated. The branching frequency value was greater than 0.20 in 'Arbequina' and in only four of the genotypes. The branching density in five genotypes was similar to 'Arbequina'. 'Arbequina' had the lowest value for the branch diameter/stem diameter ratio, and only three genotypes had similar values. These initial results showed that only one genotype has all canopy architectural characteristics comparable to those of the cv. 'Arbequina'. Further studies are needed to evaluate the production traits of these new genotypes and complete their characterization.

Transcriptomics and metabolomics reveal improved performance of Hu sheep on hybridization with Southdown sheep.

Consumers are increasingly demanding high-quality mutton. Cross breeding can improve meat quality and is widely used in sheep breeding. However, little is known about the molecular mechanism of cross breeding sheep meat quality. In this study, male Southdown and female Hu sheep were hybridized. The slaughter performance and longissimus dorsi quality of the 6-month-old hybrid offspring were measured, and the longissimus dorsi of the hybrid offspring was analyzed by transcriptomics and metabolomics to explore the effect of cross breeding on meat quality. The results showed that the production performance of Southdown × Hu F1 sheep was significantly improved, the carcass fat content was significantly decreased, and the eating quality of Southdown × Hu F1 sheep were better. Compared with the HS group (Hu × Hu), the NH group (Southdown × Hu) had 538 differentially expressed genes and 166 differentially expressed metabolites (P < 0.05), which were significantly enriched in amino acid metabolism and other related pathways. Up-regulated genes METTL21C, PPARGC1A and down-regulated gene WFIKKN2 are related to muscle growth and development. Among them, the METTL21C gene, which is related to muscle development, was highly correlated with carnosine, a metabolite related to meat quality (correlation > 0.6 and P < 0.05). Our results provide further understanding of the molecular mechanism of cross breeding for sheep muscle growth and meat quality optimization.

Mating compatibility and offspring traits evaluation among different strains of Tenebrio molitor.

The fast-growing sector of insects for food and feed stimulates researchers and the industry to explore uncharted territories, such as insect breeding, to improve economically important insect fitness traits. The yellow mealworm, Tenebrio molitor L., is one of the most thoroughly studied insect species as food and feed. However, data on mating compatibility and the effect of cross-breeding between different strains on the performance and fitness of the hybrids are scarce. In the present study, we comparatively evaluated the mating compatibility between two T. molitor inbred strains (Greek and Italian) and their outbred strains, i.e., Italian (♀)-Greek (♂) and Greek (♀)-Italian (♂), as well as the performance of their hybrid offspring. Based on the results, there is good mating compatibility among adults of the strains tested. Offspring performance, quantified as larval survival and final larval weight, followed a similar pattern among the crossings examined. Even though differences were insignificant, the outbreeding of females of the Italian strain resulted in a higher cumulative number of eggs and hatching rate and higher offspring weight. The present study sheds light on the mating compatibility of different T. molitor strains and their hybrids' economically important life table characteristics to take the mass production of insects one step further.

Population structure and phylogeography of three closely related tree peonies.

Paeonia decomposita, Paeonia rotundiloba, and Paeonia rockii are three closely related species of Sect. Moutan is distributed in the montane area of the Eastern Hengduan Mountain region. Understanding the population history of these three tree peony species could contribute to unraveling the evolutionary patterns of undergrowth species in this hotspot area. We used one nuclear DNA marker (internal transcribed spacer region, ITS) and two chloroplast DNA markers (matK, ycf1) to reconstruct the phylogeographic pattern of the populations. In total, 228 individuals from 17 populations of the three species were analyzed in this study. Three nuclear clades (Clade I - Clade III) and four maternal clades (Clade A - Clade D) were reconstructed. Molecular dating suggested that young lineages diverged during the late Pliocene and early Pleistocene, younger than the uplift of the Hengduan Mountains but older than the last glacial maximum (LGM). Significant population and phylogeographic structures were detected at both markers. Furthermore, the populations of these tree peonies were overall at equilibrium during the climatic oscillations of the Pleistocene. The simulated palaeoranges of the three species during the LGM period mostly overlapped, which could have led to cross-breeding events. We propose an evolutionary scenario in which mountain orogenesis around the Hengduan Mountain area triggered parapatric isolation between maternal lineages of tree peonies. Subsequent climatic fluctuations drove migration and range recontact of these populations along the valleys. This detailed evolutionary history provides new insights into the phylogeographic pattern of species from mountain-valley systems.

Extensive intra- and inter-genetic admixture of Chinese gamecock and other indigenous chicken breeds revealed by genomic data.

Genomic admixture is a widespread phenomenon among domestic animal breeds, including chickens. However, reports on admixture within Chinese gamecocks or other indigenous chickens are limited. This study focuses on the population genetic structure and admixture of 5 Chinese gamecock breeds and the admixture with 9 other indigenous Chinese chicken breeds. Our results showed that Turpan and Henan gamecocks were grouped into one cluster, whereas Luxi, Zhangzhou, and Xishuangbanna gamecocks were grouped into the other cluster. Gene flow occurred between Xishuangbanna and Turpan and Turpan and Luxi gamecocks. Simultaneously, gene flow was observed between gamecocks and indigenous chickens, such as Xishuangbanna and Wenchang. Ancestral component analysis indicated that modern domestic chickens in southern China played an important role in the history of the domestication of modern Chinese gamecock. Our study will be helpful in better understanding the domestication and evolution of Chinese gamecock.

Configuration of sacral plexuses in Hasmer and Hasak sheep breeds: a comparative macro-anatomical approach.

The aim of this study was to examine and compare the macro-anatomical structures and configurations of plexus sacralis in Hasmer and Hasak sheep breeds. For this purpose, 18 sheep (eight female Hasmer sheep, three male Hasak sheep and seven female Hasak sheep) were assessed. After induction of anesthesia, the body cavities were opened. The sheep were fixed with formaldehyde after draining of the blood. The nerves of the plexus sacralis were dissected separately and photographed. Both in Hasmer and Hasak sheep breeds, the plexus sacralis was a large anastomotic complex of nerves which gave rise to nerves distributed to pelvic cavity and pelvic limb. It was derived from the ventral branches of the six spinal segments. It was observed that this plexus was formed by the ventral rami of four (first to fourth) sacral spinal nerves as well as ventral ramus of the sixth and fifth lumbar nerves. The results of this study are believed to be improved further with the future morphometric studies and to make a contribution to future anatomical and surgical studies in this area.

Using Polygenic Risk Scores Related to Complex Traits to Predict Production Performance in Cross-Breeding of Yeast.

The cultivation of hybrids with favorable complex traits is one of the important goals for animal, plant, and microbial breeding practices. A method that can closely predict the production performance of hybrids is of great significance for research and practice. In our study, polygenic risk scores (PRSs) were introduced to estimate the production performance of Saccharomyces cerevisiae. The genetic variation of 971 published isolates and their growth ratios under 35 medium conditions were analyzed by genome-wide association analysis, and the precise p-value threshold for each phenotype was calculated. Risk markers for the above 35 phenotypes were obtained. By estimating the genotype of F1 hybrids according to that of the parents, the PRS of 613 F1 hybrids was predicted. There was a significant linear correlation between the maximum growth rate at 40 °C and PRS in F1 hybrids and their parents (R2 = 0.2582, R2 = 0.2414, respectively), which indicates that PRS can be used to estimate the production performance of individuals and their hybrids. Our method can provide a reference for strain selection and F1 prediction in cross-breeding yeasts, reduce workload, and improve work efficiency.

Whole genome resequencing reveals the genetic contribution of Kazakh and Swiss Brown cattle to a population of Xinjiang Brown cattle.

Xinjiang Brown cattle is characterized by wide environmental adaptation from its female parent (Kazakh cattle) and good production performance from its male parent (Swiss Brown cattle). However, the genetic basis underlying these characteristics hasnotbeenexplored. Here we compared 50 genomes of Xinjiang Brown cattle to the genomes of other eight breeds worldwide to analyze patterns of genetic variation in the Xinjiang Brown cattle. We found canonical genomic characteristics of cross breed with the lowest linkage disequilibrium and the highest effective population size. At the global level, Xinjiang Brown cattle had 9.88% Kazakh cattle and 90.12% Swiss Brown cattle inheritance. Our local ancestry inference revealed the segments with the excess of Kazakh cattle blood enriched in genes or pathways involved in digestion,absorption,metabolism and disease. More importantly, we also observed the completely fixed haplotypes inherited from Swiss Brown cattle harboring genes (LCORL, GHR, MEF2D, PCSK1 and MSRB3), KEGG pathways, cattle QTLs or human NHGRIGWAS catalog related to body measurement and growth traits. Our findings will not only help understand the process of cross breeding but can provide basic materials for further QTL mapping and improvement of important traits in Xinjiang Brown cattle.

iTRAQ and PRM -based proteomics analysis for the identification of differentially abundant proteins related to male sterility in ms-7 mutant tomato (Solanum lycoperscium) plants.

Male sterile mutants can be used in breeding or commercial cultivation in tomato, but there are few research reports on their proteomics. In this study, we analyzed the metabolic pathways and biological functions of differentially abundant proteins (DAPs) involved in two stages of stamen development of the tomato flowers by using a high through-put iTRAQ labeled proteomic approach. There was a total of 1476 DAPs which should associated with the occurrence of pollen abortion in tomato. Moreover, there were more DAPs in the four membrane systems. It shows that membrane systems are very important for tomato pollen development. According to KEGG analysis, these signaling pathways including starch and sucrose metabolism (map00500), tropane, piperidine and pyridine alkaloids biosynthesis (map00960), amino sugar and nucleotide sugar metabolism (map00520) have important effects on pollen development. These results were verified by using mass spectrometry PRM. Finally, two candidate genes (Solyc11g065770 and Solyc11g065530) were found that may be related to pollen development and cause pollen abortion by comparison of protein-protein interaction networks and on the basis of previous studies on ms-7 gene. This data and model will provide a new insight into tomato genetic male sterility 7 and contribute to the improvement of tomato hybrid breeding. Biological significance: Artificial emasculation is still the main method of tomato hybrid breeding at present. Adopting male sterility in tomato cross breeding could greatly improve the production efficiency and seed purity; reduce the cost. Although numerous researches have been conducted to select the genes related to male sterility, the molecular mechanism remains unclear in tomato. In this study, we used the high-through-put iTRAQ labeled proteomic approach, to perform a novel comparison of expression profiles in GMS tomato line and its wildtype line. Based on these results, we proposed the potential regulated protein network involved in pollen development mechanism of tomato GMS and two candidate genes. SIGNIFICANCE: Artificial emasculation is still the main method of tomato hybrid breeding at present. Adopting male sterility in tomato cross breeding could greatly improve the production efficiency and seed purity; reduce the cost. Although numerous researches have been conducted to select the genes related to male sterility, the molecular mechanism remains unclear in tomato. In this study, we used the high-through-put iTRAQ labeled proteomic approach, to perform a novel comparison of expression profiles in GMS tomato line and its wildtype line. Based on these results, we proposed the potential regulated protein network involved in pollen development mechanism of tomato GMS and two candidate genes.

Molecular Characterization, Tissue Distribution and Differential Nutritional Regulation of Three n-3 LC-PUFA Biosynthesis-Related Genes in Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂).

Elongases of very long-chain fatty acids (Elovls) and fatty acid desaturases (Fads) are crucial enzymes involved in the biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs). In this paper, we report the molecular cloning and characterization of three genes from the marine teleost Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂, and analyzed tissue distribution and their expression in response to dietary n-3 LC-PUFA levels after a 42-day feeding experiment. The elovl5, elovl8 and fads2 genes encoded 294, 263 and 445 amino acids, respectively, which exhibited all the characteristics of the Elovl and Fads family. Tissue distribution analysis revealed that elovl5, elovl8 and fads2 were widely transcribed in various tissues, with the highest level in the brain, as described in other carnivorous marine teleosts. The transcript levels of elovl5, elovl8 and fads2 in the liver were significantly affected by dietary n-3 LC-PUFA, and higher LC-PUFA levels repressed their expression. These results demonstrated, for the first time, the presence and nutritional modulation of elovl5, elovl8 and fads2 cDNA in the juvenile hybrid grouper. Further studies are needed to determine the functional characterization of these genes and explore the mechanism of these genes when regulated by dietary fatty lipid profiles in this species.

Comparison of phenotypic and heterotic effects affecting milk yield, composition and udder morphometry of Hair and F1, F2 and G1 generation cross-breeds of Alpine × Hair and Saanen × Hair dairy goats in a semi-intensive system.

This study was conducted to compare milk yield, milk components and udder traits of Hair goat, F1, F2 and G1 generation cross-breeds of Alpine × Hair and Saanen × Hair goats under a semi-intensive system. The effects of genotype, parity, flock and year on milk production, physical and chemical compositions were almost all significant (between p < 0.05 and p < 0.001). The F1, F2 and G1 generations produced 24 and 44% higher (p < 0.001) lactation milk yield (LMY), 12 and 35% (p < 0.001) fat yield and 19 and 35% (p < 0.001) protein yield than Hair goat. Positive heterosis was found in milk production and contents both Alpine × Hair F1 (AHF1) and Saanen × Hair F1 (SHF1) generations. The heterotic effect of the LMY was significant in the SHF1 generation (p < 0.05), but not in the AHF1 generation. The highest correlation was found between LMY and udder circumference and then udder volume (p < 0.001; r = from 0.34 to 0.75). The coefficient of determination of the obtained equation for the estimation of the LMY in the Hair and cross-bred goats ranged from 0.48 to 0.71. These results showed that as the level of cross-breeding increased in this semi-intensive system, better quality dairy products can be obtained from goats, and udder measurements can be a helpful tool in estimating milk yield, thus reducing the pressure on the ecosystem. Thus, it was concluded that with better modelling of environmental variations, milk production characteristics of local goats can be increased much faster by cross-breeding, especially at the F1 and G1 generation cross-breed levels.

Hatchability and growth performances of normal feathered local, Sasso-RIR and their F1-cross chickens managed under on-station condition in southern Ethiopia.

The Normal feathered local chicken (LL), Sasso-RIR (SRSR) and their F1-cross (LSR) chickens were hatched to evaluate for egg hatchability, body weight, feed efficiency, and survival rate. After 14 days of brooding, 150 chicks of each genotype were randomly selected and further replicated into five pens in a deep litter grower house consisting of 30 chicks each in a completely randomized design, and evaluated for a period of 16 weeks. Hatchability of fertile eggs was highest for LL (80.0%), intermediate for LSR (68.6%), and lowest for SRSR (55.9%) chickens. The body weight (BW) of chicks at 2 weeks of age was 80.0, 76.3, and 61.5 g/bird for SRSR, LSR, and LL, respectively, the latter being the lowest (p < 0.05). The respective BW at 8 weeks of age was 732, 587, and 451 g while at 18 weeks it was 1877, 1379, and 1070 g/bird and different from each other (p < 0.05). During 3- to 8-week and 9- to 18-week growth periods, the LL chickens were inferior (p < 0.05) in feed intake (29.7 and 66.9 g/d/bird) whereas the SRSR chickens were superior (p < 0.05) in body weight gain (15.5 and 16.3 g/d/bird) and feed conversion ratio (2.67 and 5.35 g feed/ g gain), respectively. The mortality rate of chicken was not affected by genotypes. It can be concluded that Sasso-RIR chicken genotype had played a significant role in upgrading the growth rate and market weight of the local normal feathered chicken without adverse effect on hatchability, feed efficiency, and survival rate.

An integrated transcriptomic and proteomic approach to dynamically study the mechanism of pollen-pistil interactions during jasmine crossing.

Jasmine (Jasminum sambac Aiton, Oleaceae) flowers are widely consumed in many countries for their tea-making, medicinal and ornamental properties. To improve the quality and yield of flowers, it is very important to carry out cross-breeding between different petal types of jasmine. However, because of the difficulty of sexual reproduction, there is no report on the success of jasmine crosses. In this paper, single- and double-petal jasmine plants were crossed artificially. The stigmas of single-petal plants post pollination, including those at 0 h after pollination (CK), 1 h after pollination (T1) and 6 h after pollination (T2), were sequenced by transcriptomic combined with proteomic analyses. A total of 178,098 gene products were assembled. Simultaneously, a total of 2337 protein species were identified. Some regulatory gene products and functional protein species were identified that may be involved in the process of pollen-pistil interactions. These findings suggest that the identified differentially expressed gene products and differentially accumulated protein species may play vital roles in jasmine plants in response to pollen-pistil interactions, providing important genetic resources for further functional dissection of the molecular mechanisms of these interactions. SIGNIFICANCE: These results have important scientific significance to take effective measures to overcome pre-fertilization barriers and to guide the cross breeding of jasmine. Further, they can also be used for reference in other plant breeding with the same fertilization barriers.

Phenotypic Characterization and RT-qPCR Analysis of Flower Development in F1 Transgenics of Chrysanthemum × grandiflorum.

Gene silencing is the epigenetic regulation of any gene in order to prevent gene expression at the transcription or translation levels. Among various gene silencing techniques, RNA silencing (RNAi) is notable gene regulation technique that involves sequence-specific targeting and RNA degradation. However, the effectiveness of transgene-induced RNAi in F1 generation of chrysanthemum has not been studied yet. In the current study, we used RNAi-constructed CmTFL1 (white-flowered) and CmSVP overexpressed (yellow flowered) transgenic plants of previously conducted two studies for our experiment. Cross hybridization was performed between these intergeneric transgenic and non-transgenic plants of the winter-growing chrysanthemum selection "37" (light pink flowered). The transgene CmSVP was confirmed in F1 hybrids by RT-PCR analysis, whereas hybrids of CmTFL1 parental plants were non-transgenic. Besides this, quantitative real-time PCR (qPCR) was used to explain the molecular mechanism of flower development using reference genes. Intergeneric and interspecific hybrids produced different colored flowers unlike their respective parents. These results suggest that generic traits of CmSVP overexpressed plants can be transferred into F1 generations when crossed with mutant plants. This study will aid in understanding the breeding phenomenon among intergeneric hybrids of chrysanthemum plants at an in vivo level, and such transgenics will also be more suitable for sustainable flower yield under a low-light production system.

Combination of High Zn Density and Low Phytic Acid for Improving Zn Bioavailability in Rice (Oryza stavia L.) Grain.

BACKGROUND: Zn deficiency is one of the leading public health problems in the world. Staple food crop, such as rice, cannot provide enough Zn to meet the daily dietary requirement because Zn in grain would chelate with phytic acid, which resulted in low Zn bioavailability. Breeding new rice varieties with high Zn bioavailability will be an effective, economic and sustainable strategy to alleviate human Zn deficiency. RESULTS: The high Zn density mutant LLZ was crossed with the low phytic acid mutant Os-lpa-XS110-1, and the contents of Zn and phytic acid in the brown rice were determined for the resulting progenies grown at different sites. Among the hybrid progenies, the double mutant always displayed significantly higher Zn content and lower phytic acid content in grain, leading to the lowest molar ratio of phytic acid to Zn under all environments. As assessed by in vitro digestion/Caco-2 cell model, the double mutant contained the relatively high content of bioavailable Zn in brown rice. CONCLUSIONS: Our findings suggested pyramiding breeding by a combination of high Zn density and low phytic acid is a practical and useful approach to improve Zn bioavailability in rice grain.

Improvement of Stable Restorer Lines for Blast Resistance through Functional Marker in Rice (Oryza sativa L.).

Two popular stable restorer lines, CB 87 R and CB 174 R, were improved for blast resistance through marker-assisted back-cross breeding (MABB). The hybrid rice development program in South India extensively depends on these two restorer lines. However, these restorer lines are highly susceptible to blast disease. To improve the restorer lines for resistance against blasts, we introgressed the broad-spectrum dominant gene Pi54 into these elite restorer lines through two independent crosses. Foreground selection for Pi54 was done by using gene-specific functional marker, Pi54 MAS, at each back-cross generation. Back-crossing was continued until BC3 and background analysis with seventy polymorphic SSRs covering all the twelve chromosomes to recover the maximum recurrent parent genome was done. At BC3F2, closely linked gene-specific/SSR markers, DRRM-RF3-10, DRCG-RF4-8, and RM 6100, were used for the identification of fertility restoration genes, Rf3 and Rf4, along with target gene (Pi54), respectively, in the segregating population. Subsequently, at BC3F3, plants, homozygous for the Pi54 and fertility restorer genes (Rf3 and Rf4), were evaluated for blast disease resistance under uniform blast nursery (UBN) and pollen fertility status. Stringent phenotypic selection resulted in the identification of nine near-isogenic lines in CB 87 R × B 95 and thirteen in CB 174 R × B 95 as the promising restorer lines possessing blast disease resistance along with restoration ability. The improved lines also showed significant improvement in agronomic traits compared to the recurrent parents. The improved restorer lines developed through the present study are now being utilized in our hybrid development program.

The application of genomic selection in pig cross breeding.

Genomic selection is a form of marker-assisted selection in which genetic markers covering the entire genome are used so that all quantitative trait loci are in linkage disequilibrium with at least one marker. Genomic selection improves the efficiency and accuracy of breeding and it is widely used in purebred breeding across many animal species. However, some studies indicate that the accuracy of genome selection in cross breeding needs to be improved,especially in cross population. As one of the most extensive breeding methods employed in the swine industry, cross breeding has significant, potential research and economic value to further improve its performance by combining with genomic selection. In this review, we summarize the application of genomic selection in pigs, and elucidate the genomic selection deficiencies in breeding hybrid pigs. This review will also provide valuable insights for the future application and improvement of genomic selection in pig cross breeding.

Inference of Breed Structure in Farm Animals: Empirical Comparison between SNP and Microsatellite Performance.

Knowledge of population structure is essential to improve the management and conservation of farm animal genetic resources. Microsatellites, which have long been popular for this type of analysis, are more and more neglected in favor of whole-genome single nucleotide polymorphism (SNP) chips that are now available for the main farmed animal species. In this study, we compared genetic patterns derived from microsatellites to that inferred by SNPs, considering three pairs of datasets of sheep and cattle. Population genetic differentiation analyses (Fixation index, FST), as well as STRUCTURE analyses showed a very strong consistency between the two types of markers. Microsatellites gave pictures that were largely concordant with SNPs, although less accurate. The best concordance was found in the most complex dataset, which included 17 French sheep breeds (with a Pearson correlation coefficient of 0.95 considering the 136 values of pairwise FST, obtained with both types of markers). The use of microsatellites reduces the cost and the related analyses do not require specific computer equipment (i.e., information technology (IT) infrastructure able to provide adequate computing and storage capacity). Therefore, this tool may still be a very appropriate solution to evaluate, in a first stage, the general state of livestock at national scales. At a time when local breeds are disappearing at an alarming rate, it is urgent to improve our knowledge of them, in particular by promoting tools accessible to the greatest number.

Expression of Behavioural Traits in Goldendoodles and Labradoodles.

As crossbred dogs gain in popularity, how they express inherited behaviour traits in comparison to their purebred constituent breeds is of interest. We investigated behaviours exhibited by crossbred dogs by focusing on the popular Goldendoodle and Labradoodle crossbreds and comparing them to their corresponding constituent breeds: Standard and Miniature Poodle, Golden Retriever or Labrador Retriever. The data for this study was provided by 5141 volunteer dog owners who filled out the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) online survey. The survey results were used to analyse breed differences in fourteen representative behavioural trait scores: trainability, stranger-directed aggression, owner-directed aggression, dog-directed aggression, dog rivalry, dog-directed fear, stranger-directed fear, non-social fear, touch sensitivity, separation-related problems, excitability, attachment/attention-seeking behaviours, energy and chasing. As expected from a first-generation crossbred (F1), the crossbreds in our study tend to fall between the two constituent parent breeds with some exceptions. Our results suggest that the F1 Labradoodle differed significantly from one of the pure constituent breeds only in dog rivalry, whereas the F1 Goldendoodle behaviour varied from one or more pure constituent breeds in dog rivalry, dog-directed aggression, dog-directed fear, and stranger-directed fear. These results can help advise future dog owners on behavioural trends for particular crossbreds.

Beef Production Systems with Steers of Dairy and Dairy × Beef Breeds Based on Forage and Semi-Natural Pastures.

This study compared animal performance and carcass characteristics in steers born to a dairy breed dam and a dairy or beef breed sire allocated to one out of two production systems, both including grazing semi-natural pastures during summer. Spring-born groups comprising 16 purebred dairy (D) steers and 16 dairy × Charolais crossbreeds (C) were allocated to moderately high indoor feed intensity with slaughter at 21 months of age (H), while two corresponding autumn-born groups of 16 D and 16 C animals were allocated to low indoor feed intensity with slaughter at 28 months of age (L). The animals were mainly fed grass-clover silage while housed. The H steers grazed semi-natural pastures for one summer, whereas the L steers grazed semi-natural pastures for two summers. From weaning to slaughter, liveweight gain was 0.94 and 0.77 kg day-1 for H and L steers, respectively (p < 0.0001), with no breed effect on weight gain. However, C carcasses had a higher weight, conformation score, and proportion of high-valued retail cuts than D carcasses (p ≤ 0.004). Moreover, conformation differed more between LC and LD than between HC and HD. From this study on forage and pasture-based beef production, we concluded that breed had no effect on the performance of living animals, but that dairy × beef crossbred steers produced heavier and higher-quality carcasses than pure-bred dairy steers.