Modern Breed Research Articles

Occurrence of beta-casein allele A1 in Bovidae species

In the last two decades bovine beta-casein variant A1 has attracted attention in the dairy industry as a source of beta-casomorphin-7 opioid-like peptide with potentially harmful effects on human health. Because the origin of this variant is unknown, the aim of the study was to investigate its occurrence in different species of the Bovidae family. Blood samples were taken from 137 animals belonging to 17 Bovidae species. All animals were genotyped in beta-casein locus by Illumina Bovine MDv2 Chip. The results shown that allele A1 was present in Bos taurus cattle, including primitive cattle (Watusi and Ukraine) and in a modern dairy breed (Holstein). In Dahomey cattle, two heterozygous A1A2 individuals were found. In all remaining species, no animal carrying allele A1 of beta-casein was identified. It may be concluded that allele A2 is ancestral to allele A1 and was spread especially within modern dairy cattle

A comprehensive study on milk composition and coagulation properties from six endangered native Norwegian cattle breeds

Six cattle breeds native to Norway, have for almost half a century been at risk of extinction. Due to their small population sizes, they have hardly been improved by breeding for many decades. Still, the endangered breeds represent a source of genetic diversity with special milk qualities compared to the modern breed, Norwegian red (NRF). This study reports for the first time a detailed overview of their milk composition. Milk from seven native breeds, in total 200 individuals, were included in the study. Rare genetic variants of αs1-and αs2-casein, and β-casein A1 and κ-casein B were more prevalent in milk form the endangered breeds compared to NRF. Moreover, milk from these six breeds showed better renneting properties and lower incidences of non-coagulating milk, compared to the NRF milk, which showed better acid coagulation properties. This study shows the potential for native breeds in small-scale production of high-quality rennet cheeses.

Demographic Reconstruction of the Western Sheep Expansion from Whole-Genome sequences.

As one of the earliest livestock, Sheep (Ovis aries) were domesticated in the Fertile Crescent about 12000 - 10000 years ago and have a nearly worldwide distribution today. Most of our knowledge about the timing of their expansions stems from archaeological data but it is unclear how the genetic diversity of modern sheep fits with these dates. We used whole-genome sequencing data of 63 domestic breeds and their wild relatives, the Asiatic mouflon (O. gmelini, previously known as O. orientalis), to explore the demographic history of sheep. On the global scale, our analysis revealed geographic structuring among breeds with unidirectional recent gene flow from domestics into Asiatic mouflons. We then selected four representative breeds from Spain, Morocco, the UK and Iran to build a comprehensive demographic model of the Western sheep expansion. We inferred a single domestication event around 11000 years ago. The subsequent westward expansion is dated to approximately 7000 years ago, later than the original Neolithic expansion of sheep and slightly predating the Secondary Product Revolution associated with woolly sheep. We see some signals of recent gene flow from an ancestral population into Southern European breeds which could reflect admixture with feral European mouflon. Furthermore, our results indicate that many breeds experienced a reduction of their effective population size during the last centuries, probably associated with modern breed development. Our study provides insights into the complex demographic history of Western Eurasian sheep, highlighting interactions between breeds and their wild counterparts.

On the status of greylag geese in Roman Paris: A linear and 2D geometric morphometric approach

AbstractWe investigate here the domestic status of goose remains from archaeological excavations of the Roman urban settlement of Paris Lutecia. Within the diet of the Parisii adult goose competes with chicken in importance, thus offering abundant material for exploring the question of the domesticity of this bird. We first use linear and geometric morphometrics on modern tarsometatarsi of wild and domestic greylag geese to investigate potential morphological differences between the two forms. Afterwards, we apply this model on a Roman sample from Lutecia. The modern domestic breed shows notable differences in length and gracility of the tarsometatarsus compared with the wild specimens. In domestic males, the tarsometatarsi appear significantly longer and more robust compared with females. In wild greylag geese, we do not observe significant differences between males and females. Geometric morphometric analysis shows a modification of the shape in the domestic form, with increased robusticity and a bend of the shaft towards the distal end. Following this analysis, we examine the metrical specificities of the archaeological sample that shows only an increase in robusticity and no modification of length relative to the wild form. Our linear and geometric morphometric models clearly indicate that the majority of the Roman geese are domestic. Nevertheless, a smaller number of wild greylag geese are also present and must be considered as being sourced from hunting activities in the surroundings of Lutecia.

The Australian dingo is an early offshoot of modern breed dogs.

Dogs are uniquely associated with human dispersal and bring transformational insight into the domestication process. Dingoes represent an intriguing case within canine evolution being geographically isolated for thousands of years. Here, we present a high-quality de novo assembly of a pure dingo (CanFam_DDS). We identified large chromosomal differences relative to the current dog reference (CanFam3.1) and confirmed no expanded pancreatic amylase gene as found in breed dogs. Phylogenetic analyses using variant pairwise matrices show that the dingo is distinct from five breed dogs with 100% bootstrap support when using Greenland wolf as the outgroup. Functionally, we observe differences in methylation patterns between the dingo and German shepherd dog genomes and differences in serum biochemistry and microbiome makeup. Our results suggest that distinct demographic and environmental conditions have shaped the dingo genome. In contrast, artificial human selection has likely shaped the genomes of domestic breed dogs after divergence from the dingo.

A neurochemical biogeography of the broiler chicken intestinal tract

The study of neurochemical-based interkingdom signaling and its impact on host-microbe interaction is called microbial endocrinology. Neurochemicals play a recognized role in determining bacterial colonization and interaction with the gut epithelium. While much attention has been devoted to the determination of neurochemical concentrations in the mammalian gut to better understand tissue and region-specific microbial endocrinology-based mechanisms of host-microbe interaction, little is known regarding the biogeography of neurochemicals in the avian gut. Greater resolution of avian gut neurochemical concentrations is needed especially as recent microbial endocrinology-based investigations into bacterial foodborne pathogen colonization of the chicken gut have demonstrated neurochemicals to affect Campylobacter jejuni and Salmonella spp. in vivo and in vitro. The aim of the present study was to determine the concentrations of stress-related neurochemicals in the tissue and luminal content of the duodenum, jejunum, ileum, cecum, and colon of the broiler intestinal tract, and to investigate if this biogeography changes with age of the bird. While all neurochemicals measured were detected in the intestinal tract, many displayed differences in regional concentrations. Whereas the catecholamine norepinephrine was detected in each region of the intestinal tract, epinephrine was present only in the cecum and colon. Likewise, dopamine, and its metabolite 3,4-dihydroxyphenylacetic acid were found in the greatest quantities in the cecum and colon. Serotonin and histamine were identified in each gut region. Region-specific age-related changes were observed (P < 0.05) for serotonin, its metabolite 5-hydroxyindole acetic acid as well as for histamine. Several neurochemicals, including norepinephrine, were found in the contents of each gut region. Epinephrine was not detected in the gut content of any region. Salsolinol, a microbial-produced neuroactive compound was detected in the gut content but not in tissue. Together, our data establish a neurochemical biogeography of the broiler chicken intestinal tract. By providing researchers with a region-by-region map of in vivo gut neurochemical concentrations of a modern broiler chicken breed, this neurochemical map is expected to inform future investigations that seek to utilize avian enteric neurochemistry.

Genome-Wide Analyses Reveal the Genetic Architecture and Candidate Genes of Indicine, Taurine, Synthetic Crossbreds, and Locally Adapted Cattle in Brazil

Cattle population history, breeding systems, and geographic subdivision may be reflected in runs of homozygosity (ROH), effective population size (Ne), and linkage disequilibrium (LD) patterns. Thus, the assessment of this information has become essential to the implementation of genomic selection on purebred and crossbred cattle breeding programs. In this way, we assessed the genotype of 19 cattle breeds raised in Brazil belonging to taurine, indicine, synthetic crossbreds, and Iberian-derived locally adapted ancestries to evaluate the overall LD decay patterns, Ne, ROH, and breed composition. We were able to obtain a general overview of the genomic architecture of cattle breeds currently raised in Brazil and other tropical countries. We found that, among the evaluated breeds, different marker densities should be used to improve the genomic prediction accuracy and power of genome-wide association studies. Breeds showing low Ne values indicate a recent inbreeding, also reflected by the occurrence of longer ROH, which demand special attention in the matting schemes to avoid extensive inbreeding. Candidate genes (e.g., ABCA7, PENK, SPP1, IFNAR1, IFNAR2, SPEF2, PRLR, LRRTM1, and LRRTM4) located in the identified ROH islands were evaluated, highlighting biological processes involved with milk production, behavior, rusticity, and fertility. Furthermore, we were successful in obtaining the breed composition regarding the taurine and indicine composition using single-nucleotide polymorphism (SNP) data. Our results were able to observe in detail the genomic backgrounds that are present in each breed and allowed to better understand the various contributions of ancestor breeds to the modern breed composition to the Brazilian cattle.

Introgression of ASIP and TYRP1 Alleles Explains Coat Color Variation in Valais Goats.

The Valais Blackneck goat is a Swiss goat breed with a characteristic coat color phenotype. Before the revision of the breed standard in 1938, 4 different color varieties of Valais goats were known. Besides Blackneck animals resembling the modern breed standard, the brown and white Copperneck goat, the white Capra Sempione, and the greyish Grüenochte comprised the historic Valais goats. The brown pigmentation of Copperneck goats had previously been traced back to an introgression of a mutant TYRP1 allele from Toggenburg goats. In the present study, we identified additional introgression events of distinct ASIP alleles causing the remaining 2 rare coat color patterns within the Valais Blackneck goat breed. We identified the introgression of the AWt allele from Appenzell or Saanen goats in white Capra Sempione goats. Similarly, introgression of the Apc allele from Peacock goats resulted in the greyish Grüenochte phenotype. These results demonstrate past hybridization events between breeds that are separated today. A perfect genotype-phenotype association in 393 Valais goats supported the causality of the genotyped variants for the different coat color phenotypes. Our study gives insights into the introgression of functionally relevant copy number variant (CNV) alleles controlling pigmentation between goat breeds with strikingly different coat color patterns.

KARYOTYPAL VARIABILITY OF CARPATHIAN BROWN COWS

Brown Carpathian breed of cattle bred in Transcarpathia at the end of the XIX century. and belongs to the breeds of dairy and meat productivity. Animals of the modern breed are direct descendants of the ancient Brown Carpathian cattle, common at one time throughout Central Europe. The main advantage of the Brown Carpathian breed is that it can be effectively grown on natural pastures – both in the lowlands and in the mountains. The genetics of these animals are resistant to acute infectious diseases, they are well adapted to local conditions, sensitive to improved housing and feeding conditions, and cows produce special milk, which is used in the manufacture of high quality hard cheeses and baby food. Animals of the Brown Carpathian breed belong to the local small domestic breeds and are in a state of significant risk. The uterine population is bred only in households.&#x0D; The aim of our work was to study the karyotype variability of Brown Carpathian cows, which is quite relevant today. Cytogenetic analysis, which was aimed at establishing the karyotypic variability of Brown Carpathian cows, was performed in the village. Nyzhni Vorota, Volovets district, Zakarpattia region, in households. Purebred cows of Brown Carpathian breed – (16 heads) and local animals – (11 heads) were studied.&#x0D; According to the results of cytogenetic analysis, genomic disorders, aneuploidy, were found in purebred cows of Brown Carpathian breed, which was 1.6% and was expressed mainly by hypoploid cells 2n = 56–58. For domestic animals, the frequency of metaphase plates with aneuploidy was 3.3%, which corresponds to a spontaneous level of cytogenetic variability.&#x0D; Structural chromosome abnormalities, chromosomal breaks, in purebred cows were equal to 0.76%, which does not exceed the spontaneous level of chromosomal variability. In local animals, this variability did not manifest itsel.&#x0D; The indicators of the micronucleus test (the proportion of lymphocytes with a micronucleus of 1.7–2.0‰, dinuclear lymphocytes 1.5–2.7‰, and the mitotic index of 4.8–5.5‰, respectively) in domestic animals are higher compared to purebred animals, however, do not exceed those of the species Bos taurus.&#x0D; According to the results of the cytogenetic analysis, it was established that purebred cows of Brown Carpathian breed and their crossbreeds were characterized by quantitative and structural chromosome disorders.&#x0D; Genomic disorders, aneuploidy, in local animals are 2 times higher (3.3%) compared to purebred cows of Brown Carpathian breed with a statistically significant difference in mean values (P &gt; 0.99).&#x0D; Low level or absence of structural disorders of chromosomes in purebred animals and their crossbreeds indicates a low degree of somatic mutagenesis.&#x0D; The indicators of the micronucleus test, as an indicator of the effect of the total mutagenic load on the body of the studied cows, in domestic animals are higher compared to purebred animals, however, do not exceed those characteristic of the species Bos taurus.&#x0D; It was established that the level of somatic mutagenesis is lower and the karyotype is more stable in purebred animals of the Brown Carpathian breed in comparison with the local ones.

Metabolomics shows the Australian dingo has a unique plasma profile

Dingoes occupy a wide range of the Australian mainland and play a crucial role as an apex predator with a generalist omnivorous feeding behaviour. Dingoes are ecologically, phenotypically and behaviourally distinct from modern breed dogs and have not undergone artificial selection since their arrival in Australia. In contrast, humans have selected breed dogs for novel and desirable traits. First, we examine whether the distinct evolutionary histories of dingoes and domestic dogs has lead to differences in plasma metabolomes. We study metabolite composition differences between dingoes (n = 15) and two domestic dog breeds (Basenji n = 9 and German Shepherd Dog (GSD) n = 10). Liquid chromatography mass spectrometry, type II and type III ANOVA with post-hoc tests and adjustments for multiple comparisons were used for data evaluation. After accounting for within group variation, 62 significant metabolite differences were detected between dingoes and domestic dogs, with the majority of differences in protein (n = 14) and lipid metabolites (n = 12), mostly lower in dingoes. Most differences were observed between dingoes and domestic dogs and fewest between the domestic dog breeds. Next, we collect a second set of data to investigate variation between pure dingoes (n = 10) and dingo-dog hybrids (n = 10) as hybridisation is common in regional Australia. We detected no significant metabolite differences between dingoes and dingo-dog hybrids after Bonferroni correction. However, power analysis showed that increasing the sample size to 15 could result in differences in uridine 5′-diphosphogalactose (UDPgal) levels related to galactose metabolism. We suggest this may be linked to an increase in Amylase 2B copy number in hybrids. Our study illustrates that the dingo metabolome is significantly different from domestic dog breeds and hybridisation is likely to influence carbohydrate metabolism.

What is a dingo – origins, hybridisation and identity

Controversy about the nomenclature and taxonomy of dingoes has sparked interest in their complex identity. At the root of taxonomy debates are differences in the species concepts employed, differing opinions about the domestication status of dingoes (and their ancestors) and a simplistic handling of the complex evolutionary relationship between wolves, dingoes and domestic dogs. I explore the relationship of dingoes to village dogs, modern breed dogs and wolves using genome-wide SNP data and discuss the implications of these findings to the ongoing debate about dingo identity and nomenclature. Importantly, despite controversy about what to call dingoes and whether they are a full species, these animals represent an important, distinct and unique evolutionary unit worthy of high conservation priority, as a native species. There is growing concern about the spread of domestic dog genes into dingo populations, particularly in southeastern Australia, and the impact this has on conservation goals. However, the discovery of biogeographic subdivision within dingoes raises questions about the accuracy of the current methods used for estimating dog vs dingo ancestry. I caution scientists and wildlife managers to carefully consider the limitations of current ancestry estimate methods when assessing DNA test results. Future work using genome-wide DNA technology to improve dingo ancestry estimates will be fundamental to ongoing debate about what dingoes are, how to identify dingoes and how to conserve them.

The link between selection for function and human-directed play behaviour in dogs.

Human-directed play behaviour is a distinct behavioural feature of domestic dogs. But the role that artificial selection for contemporary dog breeds has played for human-directed play behaviour remains elusive. Here, we investigate how human-directed play behaviour has evolved in relation to the selection for different functions, considering processes of shared ancestry and gene flow among the different breeds. We use the American Kennel Club (AKC) breed group categorization to reflect the major functional differences and combine this with observational data on human-directed play behaviour for over 132 breeds across 89 352 individuals from the Swedish Dog Mentality Assessment project. Our analyses demonstrate that ancestor dogs already showed intermediate levels of human-directed play behaviour, levels that are shared with several modern breed types. Herding and Sporting breeds display higher levels of human-directed play behaviour, statistically distinguishable from Non-sporting and Toy breeds. Our results suggest that human-directed play behaviour played a role in the early domestication of dogs and that subsequent artificial selection for function has been important for contemporary variation in a behavioural phenotype mediating the social bond with humans.

CONDITION AND PROSPECTS INITIATED BY PROFESSOR V. YU. NEDAVA RESEARCH IN NANOBIOTECHNOLOGY

Doctor of Agricultural Sciences, Professor Volodymyr Yukhymovich Nedava (1925–2009) made a significant contribution to the development of selection, genetics and biotechnology in animal husbandry in Ukraine. His efforts laid the foundation for biotechnological foundations of farm animal reproduction and modern breed theory, substantiated the use of heterosis in livestock, effective methods of improving the brown Carpathian breed, simplified the method of assessing breeding animals for feed production. Goal. To analyze the directions of scientific activity of Doctor of Agricultural Sciences, Professor V. Yu. Nedava in the context of development of research in nanobiotechnology and to generalize its main achievements in developing the theory and methodology of application of ultra fine silica in media for cryopreservation of sperm farm animals. Methods. General scientific (analytical-synthetic, logical, systemic), biographical and source methods. The source base of the research covers a wide range of materials, which are based on archival documents and primary sources, scientific works (publications), reports and memoirs of colleagues about the talented scientist. Results. At the initiative and direct participation of V. Yu. Nedava, a method was developed for the treatment of bull semen, which differed from the conventional one in that in order to stabilize the biological value, to the freshly obtained sperm before dilution is added UFS at the rate of 3–30 mg per 1 billion sperm. Later, Professor V. Yu. Nedava and co-authors published the results of research on the use of fine pyrogenic UFS (Aerosil) as a stabilizer of the biological value of bull sperm, which was confirmed by higher fertility rates of heifers after insemination with Aerosil sperms (5.8% higher compared to control). Continuation of the initiated research of V. Yu. Nedava on the use of ultra fine silica to stabilize the cell surface of reproductive gametes was research on improving the technology of in vitro embryo formation and cryopreservation of male epididymal sperm using nanomaterials, which began in 2007. Conclusions. A number of scientific works of Professor Volodymyr Yukhymovich Nedava testify to his talented organizational and scientific character traits, which have a continuation in our time. V. Yu. Nedava initiated the development of the concept of VDK processing of semen of farm animals, determined their purpose in the system of conservation of genetic resources of farm animals, substantiated the importance of using such materials as the main link in the conservation of farm animals.

Spy game: verifying a local generic solver in Iris

We verify the partial correctness of a "local generic solver", that is, an on-demand, incremental, memoizing least fixed point computation algorithm. The verification is carried out in Iris, a modern breed of concurrent separation logic. The specification is simple: the solver computes the optimal least fixed point of a system of monotone equations. Although the solver relies on mutable internal state for memoization and for "spying", a form of dynamic dependency discovery, it is apparently pure: no side effects are mentioned in its specification. As auxiliary contributions, we provide several illustrations of the use of prophecy variables, a novel feature of Iris; we establish a restricted form of the infinitary conjunction rule; and we provide a specification and proof of Longley's modulus function, an archetypical example of spying.

The dependence of the growth rate and meat content of young boars on semen parameters and conception rate

Boars have a decisive impact on the progress in pig production, however, there is no recent information about the optimal growth parameters during the rearing period for modern breed later used in artificial insemination (AI) stations. Therefore, the objective of the research was to conduct semen parameter and conception rate analyses on the basis of growth rate and meat content assessments made during the rearing of AI boars of different genotypes. The study was carried out between 2010 and 2014 and included 184 boars in five breed combinations: 46 Polish Large White, 50 Polish Landrace, 27 Pietrain, 36 Duroc×Pietrain and 25 Hampshire×Pietrain. Boars were qualified by daily gains and meat content assessment (between 170 and 210 days of life). A total number of 38 272 ejaculates were examined (semen volume (ml), spermatozoa concentration (×106 ml−1), total number of spermatozoa (×109) and number of insemination doses from one ejaculate (n)). The fertility was determined by the conception rate (%). Semen volume, spermatozoa concentration and conception rate (P<0.01), followed by the total number of spermatozoa and insemination doses (P<0.05) were characterized by the highest variability in relation to breed of boars. The effect of daily gains was reported for spermatozoa concentration, number of insemination doses, conception rate (all P<0.01) and total number of spermatozoa (P<0.05). The peak of growth for spermatozoa concentration, total number of spermatozoa, insemination doses and conception rate was achieved for 800 to 850 g gains. Meat content affected semen volume, number of insemination doses and conception rate (P<0.05). Rearing boars while maintaining daily gains at the 800 to 850 g level and 62.5% to 65% meat content helps AI stations to increase the efficiency and economic profitability, and the number of insemination doses to increase by up to 300 doses/boar within a year. The analyses of growth parameters may help increase the efficiency and economic viability of AI stations.

ASSESSMENT OF BULLS ON THEIR OWN PERFORMANCE AS A PART OF IMPROVING DOMESTIC POPULATION ABERDEEN-ANGUS BREED OF CATTLE

ASSESSMENT OF BULLS ON THEIR OWN PERFORMANCE AS A PART OF IMPROVING DOMESTIC POPULATION ABERDEEN-ANGUS BREED OF CATTLE

Inferring Population Size History from Large Samples of Genome-Wide Molecular Data - An Approximate Bayesian Computation Approach.

Inferring the ancestral dynamics of effective population size is a long-standing question in population genetics, which can now be tackled much more accurately thanks to the massive genomic data available in many species. Several promising methods that take advantage of whole-genome sequences have been recently developed in this context. However, they can only be applied to rather small samples, which limits their ability to estimate recent population size history. Besides, they can be very sensitive to sequencing or phasing errors. Here we introduce a new approximate Bayesian computation approach named PopSizeABC that allows estimating the evolution of the effective population size through time, using a large sample of complete genomes. This sample is summarized using the folded allele frequency spectrum and the average zygotic linkage disequilibrium at different bins of physical distance, two classes of statistics that are widely used in population genetics and can be easily computed from unphased and unpolarized SNP data. Our approach provides accurate estimations of past population sizes, from the very first generations before present back to the expected time to the most recent common ancestor of the sample, as shown by simulations under a wide range of demographic scenarios. When applied to samples of 15 or 25 complete genomes in four cattle breeds (Angus, Fleckvieh, Holstein and Jersey), PopSizeABC revealed a series of population declines, related to historical events such as domestication or modern breed creation. We further highlight that our approach is robust to sequencing errors, provided summary statistics are computed from SNPs with common alleles.

Labrador retrievers are more attracted to water than to social stimuli: A pilot study

Abstract The Labrador retriever is a breed of domestic dog ( Canis lupus familiaris / Canis familiaris ) of great importance to our current society. This breed was selected to be an excellent water dog and to work with fishermen. Because of its origins, the popular belief is that Labrador retrievers are keen water lovers. However, the extent to which this is true, and whether recent selection pressures might have changed the breed is unknown. In this pilot work, we investigated the relative importance of water as a behavioral stimulus for the modern breed. The study was conducted in an arena with a swimming pool to evaluate differences in the frequency of approach behaviors and the duration of interaction behaviors toward 3 stimuli: water, dog, and human. The behaviors were measured during 2-minute periods for each Labrador retriever (N = 10), in 3 trials, with all the stimuli present at the same time in the arena. The dogs interacted significantly longer with the water stimulus than with the dog and the human stimuli. The median of the frequency of approach to the water stimulus was significantly different from the median frequency of approach to the dog stimulus. The water appeared to be a positive stimulus for this group of Labrador retrievers and the most appealing of the 3 stimuli in the specific test condition. With this pilot study, we sought to introduce novel research in terms of needs and preferences of specific dog breeds, with particular relevance of regular contact with swimming water to the welfare of this breed.

Resource use by old and modern dairy cattle breeds on semi-natural mountain pastures, Central Norway

The objective of this pilot study was to compare resource use in a mountainous summer farming landscape between old and modern dairy cow breeds during a five-day period. The modern breed used a larger part of the landscape than the old breed, most likely due to differences in habitat patterns. The old breed group preferred semi-natural pastures, while the modern breed preferred overgrown semi-natural meadows, intermediate fen, intermediate wooded fen, and grass-rich sub-alpine birch woodland. Both breeds spent most time grazing grasses, but the modern breed showed a higher frequency of grasses and Vaccinium myrtillus in its diet, while the old breed showed a higher frequency of bushes and trees. The pilot study shows some trends supplementing and strengthening earlier results on how modern and traditional cattle breeds are differing in their impact on vegetation based on their use of space and their different diets.

Traditional vs modern: role of breed type in determining enteric methane emissions from cattle grazing as part of contrasting grassland-based systems.

Ruminant livestock turn forages and poor-quality feeds into human edible products, but enteric methane (CH4) emissions from ruminants are a significant contributor to greenhouse gases (GHGs) and hence to climate change. Despite the predominance of pasture-based beef production systems in many parts of Europe there are little data available regarding enteric CH4 emissions from free-ranging grazing cattle. It is possible that differences in physiology or behaviour could influence comparative emissions intensities for traditional and modern breed types depending on the nutritional characteristics of the herbage grazed. This study investigated the role of breed type in influencing CH4 emissions from growing beef steers managed on contrasting grasslands typical of intensive (lowland) and extensive (upland) production systems. Using the SF6 dilution technique CH4 emissions were estimated for a modern, fast-growing crossbred (Limousin cross) and a smaller and hardier native breed (Welsh Black) when grazing lowland perennial ryegrass (high nutritional density, low sward heterogeneity) and semi-improved upland pasture (low/medium nutritional density, high sward heterogeneity). Live-weight gain was substantially lower for steers on the upland system compared to the lowland system (0.31 vs. 1.04 kg d−1; s.e.d. = 0.085 kg d−1; P<0.001), leading to significant differences in estimated dry matter intakes (8.0 vs. 11.1 kg DM d−1 for upland and lowland respectively; s.e.d. = 0.68 kg DM d−1; P<0.001). While emissions per unit feed intake were similar for the lowland and upland systems, CH4 emissions per unit of live-weight gain (LWG) were substantially higher when the steers grazed the poorer quality hill pasture (760 vs 214 g kg−1 LWG; s.e.d. = 133.5 g kg−1 LWG; P<0.001). Overall any effects of breed type were relatively small relative to the combined influence of pasture type and location.