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The aim of this research was to study the potential for selection of cows with a higher nutritional quality of milk fat by studying the differences in fatty acid profiles within and across the following breeds: Dual Purpose Belgian Blue, Holstein-Friesian, Jersey, Montbeliarde, and non-Holstein Meuse-Rhine-Yssel type Red and White. Six hundred milk samples from 275 animals were taken from 7 herds. Several types of fatty acids in milk and milk fat were quantified using mid-infrared spectrometry and previously obtained calibration equations. Statistical analyses were made using a mixed linear model with a random animal effect. The variance components were estimated by using REML. Results showed breed differences for the fatty acid profile. The repeatability estimate obtained in the present study may suggest the existence of moderate additive genetic variance for the fatty acid profile within each breed. Results also indicated variation for each analyzed milk component in the whole cow population studied. Genetic improvement of the nutritional quality of milk fat based on fatty acid profiles might be possible, and further research and development are warranted.

The objectives of this study were to estimate genetic parameters and the influence of systematic effects on behavior test results in dogs. Behavior test results on 1,813 Labrador Retrievers (LR) and 2,757 German Shepherd Dogs (GSD) were analyzed. The behavior test included observations on courage, defense drive, prey drive, nerve stability, temperament, cooperation, affability, and gun shyness. Sex and age influenced most of the traits, and seasons of birth and testing and litter size and composition influenced some of the traits. Apart from defense drive in GSD, and courage, nerve stability, hardness, and affability in LR, all traits were heritable, with heritabilities ranging from 0.14 for hardness to 0.38 for affability in GSD, and from 0.03 for affability to 0.56 for gun shyness in LR. Genetic correlations ranged from 1.00 (LR) and 0.95 (GSD) between courage and hardness to -0.01 (LR) and -0.03 (GSD) between gun shyness and defense drive. Most genetic correlations were positive. Correlations with cooperation were mainly negative, especially in GSD. Genetic correlations between courage and defense drive in LR (0.26) and GSD (0.80), between courage and prey drive in LR (0.27) and GSD (0.65), between affability and nerve stability in LR (0.09) and GSD (0.64), between affability and temperament in LR (-0.24) and GSD (0.39), and between cooperation and hardness in LR (0.28) and GSD (-0.67) were significantly different between the breeds. Genetic parameters for defense drive and cooperation in GSD and hardness and gun shyness in LR were genetically different between the sexes. Results of this study indicate that correction for systematic effects is essential when making selection decisions. Estimating breeding values would be a good solution, incorporating both correction for systematic effects and using all genetic links. Genetic parameters need to be estimated for each breed separately.

Heterosis and breed differences were estimated for milk yield traits, somatic cell score (SCS), and productive life (PL), a measure of longevity. Yield trait data were from 10,442 crossbreds and 140,421 purebreds born since 1990 in 572 herds. Productive life data were from 41,131 crossbred cows and 726,344 purebreds born from 1960 through 1991. The model for test-day yields and SCS included effects of herd-year-season, age, lactation stage, regression on sire's predicted transmitting ability, additive breed effects, heterosis, and recombination. The model for PL included herd-year-season, breed effects, and general heterosis. All effects were assumed to be additive, but estimates of heterosis were converted to a percentage of the parent breed average for reporting. Estimates of general heterosis were 3.4% for milk yield, 4.4% for fat yield, and 4.1% for protein yield. A coefficient of general recombination was derived for multiple-breed crosses, but recombination effects were not well estimated and small gains, not losses, were observed for yield traits in later generations. Heterosis for SCS was not significant. Estimated heterosis for PL was 1.2% of mean productive life and remained constant across the range of birth years. Protein yield of Brown Swiss×Holstein crossbreds (0.94 kg/d) equaled protein yield of purebred Holsteins. Fat yields of Jersey×Holstein and Brown Swiss×Holstein crossbreds (1.14 and 1.13 kg/d, respectively) slightly exceeded that of Holsteins (1.12 kg/d). With cheese yield pricing and with all traits considered, profit from these crosses exceeded that of Holsteins for matings at breed bases. For elite matings, Holsteins were favored because the range of evaluations is smaller and genetic progress is slower in breeds other than Holstein, in part because fewer bulls are sampled. A combined national evaluation of data for all breeds and crossbreds may be desirable but would require an extensive programming effort. Animals should receive credit for heterosis when considered as mates for another breed.

The objective of this study was to investigate the growth- and breed-related changes of marbling characteristics in cattle. Four cattle breeds with different growth impetus and muscularity were reared and slaughtered under experimental conditions. German Angus, as a typical beef cattle; Galloway, as a smaller, environmentally resistant beef cattle; Holstein-Friesian, as a dairy-type cattle; and double-muscled Belgian Blue, as an extreme type for muscle growth, were used. These 4 breeds were expected to have differences in muscle development and i.m. fat deposition. Between 5 and 15 bulls of each breed were slaughtered at 2, 4, 6, 12, or 24 mo of age. Marbling characteristics were determined and classified in LM and semitendinosus muscle by computerized image analysis. Among breeds, differences appeared in the quantity, structure, and distribution of the marbling flecks in both muscles. The deposition of fat in the double-muscled Belgian Blue bulls remained substantially inferior to that of the other breeds, up to the age of 24 mo. Marbling in German Angus bulls particularly showed larger (P < 0.05) marbling fleck areas. Galloway cattle had the greatest (P < 0.05) number and the most regular (P < 0.05) distribution of the marbling flecks in young animals. Furthermore, for marbling characteristics in Holstein-Friesian animals, a great number and slightly finer structure were observed compared with the other breeds investigated. Postnatal growth-related changes of marbling in LM were characterized by as much as a 40-fold increase in the number of marbling flecks from 2 to 24 mo of age but also by up to a 4-fold enlargement in the area of the marbling flecks. The structure of marbling flecks was determined by 2 development trends. On the one hand, the marbling flecks became larger (P < 0.05), and the structure became coarser, which was reflected by an increasing (P < 0.01) proportion of long marbling flecks as well as an increasing (P < 0.01) maximum skeleton line length. On the other hand, continually new small, round marbling flecks appeared. This caused a decrease (P < 0.01) in the proportion of the 3 largest marbling fleck areas. The distribution of the marbling flecks became more regular (P < 0.05) with increasing proportion and number of marbling flecks. The results suggest that hyperplasia of adipocytes plays an important role in marbling during growth of muscle in cattle.

The capacity for protein deposition in Iberian pigs is lower than in modern (e.g., Landrace) pig breeds, and the reasons for this remain unknown. The hypothesis tested in this work is that under similar nutritional and physiological conditions, whole-body protein turnover as well as the protein synthesis to protein deposition ratio differs between Iberian and Landrace breeds, resulting in dissimilar protein deposition rates. As a main objective, these variables were compared at different protein and Lys intakes in growing gilts. The study examined the effect of Lys deficiency because this is the prevalent condition during the fattening period of the Iberian pig in the Mediterranean forest, where the main feed source is oak acorn, which provides approximately one-third of the available Lys present in an ideal protein. Three diets were tested within each breed: 2 diets with an optimal essential AA pattern, containing 12 or 16% CP as-fed, or a Lys-deficient diet (35% of the recommended Lys content). This diet was supplied at 12% CP for the Iberian and 16% CP for the Landrace pigs, respectively. The contrasts made were breed x dietary protein concentration and breed x AA pattern (adequate vs. inadequate Lys content). Cumulative urinary ¹⁵N excretion over 60 h after receiving an oral dose of [¹⁵N]-glycine was used to calculate N flux. Mean BW for Landrace and Iberian pigs were 25.8 ± 0.55 kg and 30.8 ± 0.74 kg, respectively. Protein deposition (g of N/(kg⁰.⁷⁵·d) was lower in the Iberian than in the Landrace gilts (4 to 16%; P = 0.002) and increased with dietary protein content. In contrast, protein synthesis and degradation [g of N/(kg⁰.⁷⁵·d)] were greater for the Landrace breed (16 to 18 and 23%, respectively, for the 2 dietary protein contents studied; P < 0.05), but no breed differences were detected in fractional protein synthesis and degradation rates. The ratio of protein synthesis:protein deposition (S/PD) did not change with dietary protein concentration or breed and achieved a mean value of 5.4. Irrespective of breed, Lys deficiency had a strong negative effect on N balance (P < 0.001) and increased the ratio of S/PD (P = 0.012). The greater rates of protein deposition, synthesis, and degradation in Landrace pigs than in Iberian pigs fed optimal AA-pattern diets were then attributed to differences in body protein mass. Consequently, these results validate the hypothesis of unequal synthesis and degradation, but not of unequal S/PD, between breeds.

Across mammals, increased body size is positively associated with lifespan. However, within species, this relationship is inverted. This is well illustrated in dogs (Canis familiaris), where larger dogs exhibit accelerated life trajectories: growing faster and dying younger than smaller dogs. Similarly, some age-associated traits (e.g., growth rate and physiological pace of aging) exhibit accelerated trajectories in larger breeds. Yet, it is unknown whether cognitive performance also demonstrates an accelerated life course trajectory in larger dogs. Here, we measured cognitive development and aging in a cross-sectional study of over 4000 dogs from 66 breeds using nine memory and decision-making tasks performed by citizen scientists as part of the Dognition project. Specifically, we tested whether cognitive traits follow a compressed (accelerated) trajectory in larger dogs, or the same trajectory for all breeds, which would result in limited cognitive decline in larger breeds. We found that all breeds, regardless of size or lifespan, tended to follow the same quadratic trajectory of cognitive aging—with a period of cognitive development in early life and decline in later life. Taken together, our results suggest that cognitive performance follows similar age-related trajectories across dog breeds, despite remarkable variation in developmental rates and lifespan.

Trait heritability is necessary for evolution by both natural and artificial selection, yet we know little about the heritability of cognitive traits. Domestic dogs are a valuable study system for questions regarding the evolution of phenotypic diversity due to their extraordinary intraspecific variation. While previous studies have investigated morphological and behavioral variation across dog breeds, few studies have systematically assessed breed differences in cognition. We integrated data from Dognition.com—a citizen science project on dog cognition—with breed-averaged genetic data from published sources to estimate the among-breed heritability of cognitive traits using mixed models. The resulting dataset included 11 cognitive measures for 1508 adult dogs across 36 breeds. A factor analysis yielded four factors interpreted as reflecting inhibitory control, communication, memory, and physical reasoning. Narrow-sense among-breed heritability estimates—reflecting the proportion of cognitive variance attributable to additive genetic variation—revealed that scores on the inhibitory control and communication factors were highly heritable (inhibitory control: h2 = 0.70; communication: h2 = 0.39), while memory and physical reasoning were less heritable (memory: h2 = 0.17; physical reasoning: h2 = 0.21). Although the heritability of inhibitory control is partially explained by body weight, controlling for breed-average weight still yields a high heritability estimate (h2 = 0.50), while other factors are minimally affected. Our results indicate that cognitive phenotypes in dogs covary with breed relatedness and suggest that cognitive traits have strong potential to undergo selection. The highest heritabilities were observed for inhibitory control and communication, both of which are hypothesized to have been altered by domestication.

We investigated whether dogs ( Canis familiaris ) distinguish between human true (TB) and false beliefs (FB). In three experiments with a pre-registered change of location task, dogs ( n = 260) could retrieve food from one of two opaque buckets after witnessing a misleading suggestion by a human informant (the ‘communicator’) who held either a TB or a FB about the location of food. Dogs in both the TB and FB group witnessed the initial hiding of food, its subsequent displacement by a second experimenter, and finally, the misleading suggestion to the empty bucket by the communicator. On average, dogs chose the suggested container significantly more often in the FB group than in the TB group and hence were sensitive to the experimental manipulation. Terriers were the only group of breeds that behaved like human infants and apes tested in previous studies with a similar paradigm, by following the communicator's suggestion more often in the TB than in the FB group. We discuss the results in terms of processing of goals and beliefs. Overall, we provide evidence that pet dogs distinguish between TB and FB scenarios, suggesting that the mechanisms underlying sensitivity to others' beliefs have not evolved uniquely in the primate lineage.

A substantial increase in grain yield potential is required, along with better use of water and fertilizer, to ensure food security and environmental protection in future decades. For improvements in photosynthetic capacity to result in additional wheat yield, extra assimilates must be partitioned to developing spikes and grains and/or potential grain weight increased to accommodate the extra assimilates. At the same time, improvement in dry matter partitioning to spikes should ensure that it does not increase stem or root lodging. It is therefore crucial that improvements in structural and reproductive aspects of growth accompany increases in photosynthesis to enhance the net agronomic benefits of genetic modifications. In this article, six complementary approaches are proposed, namely: (i) optimizing developmental pattern to maximize spike fertility and grain number, (ii) optimizing spike growth to maximize grain number and dry matter harvest index, (iii) improving spike fertility through desensitizing floret abortion to environmental cues, (iv) improving potential grain size and grain filling, and (v) improving lodging resistance. Since many of the traits tackled in these approaches interact strongly, an integrative modelling approach is also proposed, to (vi) identify any trade-offs between key traits, hence to define target ideotypes in quantitative terms. The potential for genetic dissection of key traits via quantitative trait loci analysis is discussed for the efficient deployment of existing variation in breeding programmes. These proposals should maximize returns in food production from investments in increased crop biomass by increasing spike fertility, grain number per unit area and harvest index whilst optimizing the trade-offs with potential grain weight and lodging resistance.

When a genetic marker and a quantitative trait locus (QTL) are in linkage disequilibrium (LD) in one population, they may not be in LD in another population or their LD phase may be reversed. The objectives of this study were to compare the extent of LD and the persistence of LD phase across multiple cattle populations. LD measures r and r2 were calculated for syntenic marker pairs using genomewide single-nucleotide polymorphisms (SNP) that were genotyped in Dutch and Australian Holstein–Friesian (HF) bulls, Australian Angus cattle, and New Zealand Friesian and Jersey cows. Average r2 was ∼0.35, 0.25, 0.22, 0.14, and 0.06 at marker distances 10, 20, 40, 100, and 1000 kb, respectively, which indicates that genomic selection within cattle breeds with r2 ≥ 0.20 between adjacent markers would require ∼50,000 SNPs. The correlation of r values between populations for the same marker pairs was close to 1 for pairs of very close markers (<10 kb) and decreased with increasing marker distance and the extent of divergence between the populations. To find markers that are in LD with QTL across diverged breeds, such as HF, Jersey, and Angus, would require ∼300,000 markers.