Longevity Traits Research Articles

Sicilian Semi- and Supercentenarians: Age-related NK Cell Immunophenotype and Longevity Trait Definition.

The immune system of semi- and supercentenarians (i.e., the oldest centenarians) is believed to have peculiar characteristics that enable them to reach extreme longevity in a relatively healthy state. Therefore, in previous papers, we investigated, through flow cytometry, variations in the percentages of the main subsets of Tαβ and Tγδ cells in a Sicilian cohort of 28 women and 26 men (age range 19-110 years), including 11 long-living individuals (>90 years old) and 8 oldest centenarians. These investigations suggested that some observed immunophenotypic changes may contribute to the extreme longevity of the oldest centenarians. In the present study, to further characterize the immunophenotype of the oldest centenarians, we examined the percentages of Natural Killer (NK) cells identified as CD3-CD56 + CD16+ in the previously described Sicilian cohort. We found a highly significant increase in NK cell percentages with age. When stratified by gender, this significant increase with age was maintained in both sexes, with higher significance observed in males. Our findings on NK cells, together with the previously obtained results, discussed in the context of the literature, suggest that these changes are not unfavourable for centenarians, including the oldest ones, supporting the hypothesis that immune aging should be considered as a differential adaptation rather than a general immune alteration. These adapted immune mechanisms allow the oldest centenarians to successfully adapt to a history of insults and achieve remarkable longevity.

Endocrine and epigenetic regulation as common pathways underlying the genetic basis of sleep traits and longevity.

The amount of sleep needed over one's lifespan is age dependent and not sleeping enough or sleeping in excess is associated with increased morbidity and mortality. Yet the convergent molecular mechanisms that link longevity and sleep are largely unknown. We performed a gene enrichment study that (1) identified genes associated with both longevity and sleep traits and (2) determined molecular pathways enriched among these shared genes. We manually curated two sets of genes, one associated with longevity and aging and the other with sleep traits (e.g. insomnia, narcolepsy, sleep duration, chronotype, among others), with both gene lists heavily driven by hits from recent large-scale genome-wide association studies. There were 47 overlapping genes between the gene list associated with sleep traits (1,064 genes total) and the genes associated with longevity (367 genes total), indicating significantly more overlap than expected by chance. An over-representation analysis identified enriched pathways that suggest endocrine and epigenetic regulation as potential shared mechanisms between sleep traits and longevity. Concordantly, functional network analysis retrieved two clusters, being one associated with proteins of nuclear functions and the other, with extracellular proteins. This overlapping gene set, and the highlighted biological pathways may serve as preliminary findings for new functional investigations of sleep and longevity shared genetic mechanisms.

Consistency of dry matter intake in Holstein cows: Heritability estimates and associations with feed efficiency

Resilience can be defined as the capacity to maintain performance or bounce back to normal functioning after a perturbation, and studying fluctuations in daily feed intake may be an effective way to identify resilient dairy cows. Our goal was to develop new phenotypes based on daily dry matter intake (DMI) consistency in Holstein cows, estimate genetic parameters and genetic correlations with feed efficiency and milk yield consistency, and evaluate their relationships with production, longevity, health, and reproduction traits. Data consisted of 397,334 daily DMI records of 6,238 lactating Holstein cows collected from 2007 to 2022 at 6 research stations across the United States. Consistency phenotypes were calculated based on the deviations from expected daily DMI for individual cows during their respective feeding trials, which ranged from 27 to 151 d in duration. Expected values were derived from different models, including simple average, quadratic and cubic quantile regression with a 0.5 quantile, and LOESS (Locally Weighted Scatterplot Smoothing) regression with span parameters 0.5 and 0.7. We then calculated the log of variance (log-Var-DMI) of daily deviations for each model as the consistency phenotype. Consistency of milk yield was also calculated, as a reference, using the same methods (log-Var-Milk). Genetic parameters were estimated using an animal model, including lactation, days in milk and cohort as fixed effects, and animal as random effect. Relationships between log-Var-DMI and traits currently considered in the US national genetic evaluation were evaluated using Spearman's rank correlations between sires' breeding values. Heritability estimates for log-Var-DMI ranged from 0.11 ± 0.02 to 0.14 ± 0.02 across models. Different methods (simple average, quantile regressions, and LOESS regressions) used to calculate log-Var-DMI yielded very similar results, with genetic correlations ranging from 0.94 to 0.99. Estimated genetic correlations between log-Var-DMI and log-Var-Milk ranged from 0.51 to 0.62. Estimated genetic correlations between log-Var-DMI and feed efficiency ranged from 0.55 to 0.60 with secreted milk energy, 0.59 to 0.63 with metabolic body weight (BW), and 0.26 to 0.31 with residual feed intake. Relationships between log-Var-DMI and the traits in the national genetic evaluation were moderate and positive correlations with milk yield (0.20 to 0.21), moderate and negative correlations with female fertility (-0.07 to -0.20), no significant correlations with health and longevity, and favorable correlations with feed efficiency (-0.23 to -0.25 with Feed Saved and 0.21 to 0.26 with RFI). We concluded that DMI consistency is heritable and may be an indicator of resilience. Cows with lower variation in the difference between actual and expected daily DMI (more consistency) may be more effective in maintaining performance in the face of challenges or perturbations, whereas cows with greater variation in observed versus expected daily DMI (less consistency) are less feed efficient and may be less resilient.

Impact of Inbreeding and Ancestral Inbreeding on Longevity Traits in German Brown Cows.

A recent study on the population structure of the German Brown population found increasing levels of classical and ancestral inbreeding coefficients. Thus, the aim of this study was to determine the effects of inbreeding depression and purging on longevity traits using classical and ancestral inbreeding coefficients according to Kalinowski (2002) (Fa_Kal, FNew), Ballou (1997) (Fa_Bal), and Baumung (2015) (Ahc). For this purpose, uncensored data of 480,440 cows born between 1990 and 2001 were available. We analyzed 17 longevity traits, including herd life, length of productive life, number of calvings, lifetime and effective lifetime production for milk, fat, and protein yield, the survival to the 2nd, 4th, 6th, 8th, and 10th lactation number, and the culling frequencies due to infertility, or udder and foot and leg problems. Inbreeding depression was significant and negative for all traits but for culling due to udder and to foot and leg problems. When expressed in percentages of genetic standard deviations, inbreeding depression per 1% increase in inbreeding was -3.61 to -10.98%, -2.42 to -2.99%, -2.21 to -4.58%, and 5.13% for lifetime production traits, lifetime traits, survival rates, and culling due to infertility, respectively. Heterosis and recombination effects due to US Brown Swiss genes were positive and counteracted inbreeding depression. The effects of FNew were not significantly different from zero, while Fa_Kal had negative effects on lifetime and lifetime production traits. Similarly, the interaction of F with Fa_Bal was significantly negative. Thus, purging effects could not be shown for longevity traits in German Brown. A possible explanation may be seen in the breed history of the German Brown, that through the introgression of US Brown Swiss bulls ancestral inbreeding increased and longevity decreased. Our results show, that reducing a further increase in inbreeding in mating plans is advisable to prevent a further decline in longevity due to inbreeding depression, as purging effects were very unlikely in this population.

Sicilian semi- and supercentenarians: identification of age-related T-cell immunophenotype to define longevity trait.

The immunophenotype of oldest centenarians, i.e. semi- and supercentenarians, could provide important information about their ability to adapt to factors associated with immune changes, including ageing per se and chronic Cytomegalovirus infection. We investigated, by flow cytometry, variations in percentages and absolute numbers of immune cell subsets, focusing on T cells, and pro-inflammatory parameters in a cohort of 28 women and 26 men (age range 19-110 years). We observed variability in hallmarks of immunosenescence related to age and Cytomegalovirus serological status. The eight oldest centenarians showed the lowest percentages of naïve T cells, due to their age, and the highest percentages of T-effector memory cells re-expressing CD45RA (TEMRA), according to their cytomegalovirus status, and high levels of serum pro-inflammatory parameters, although their means were lower than that of remaining 90+ donors. Some of them showed CD8 naïve and TEMRA percentages, and exhaustion/pro-inflammatory markers comparable to the younger ones. Our study supports the suggestion that immune ageing, especially of oldest centenarians, exhibits great variability that is not only attributable to a single contributor but should also be the full result of a combination of several factors. Everyone ages differently because he/she is unique in genetics and experience of life and this applies even more to the immune system; everybody has had a different immunological history. Furthermore, our findings on inflammatory markers, TEMRA and CMV seropositivity in centenarians, discussed in the light of the most recent literature, suggest that these changes might be not unfavourable for centenarians, and in particular for the oldest ones.

Comparative study between Shami and Holstein cows for longevity and productive lifetime traits under subtropical conditions

This study aimed to compare the longevity and productive lifetime traits between Shami and Hol-stein cows under subtropical conditions, in addition to assess the effect of age at first calving (AFC), first lactation milk yield (FLMY), year and season of first calving on the studied traits in both breeds. The available data included 495 records for Shami and 1129 records for Holstein from birth to disposal date during the period from 1982 to 2014.The studied traits were lifespan (LS), productive life (PL), cow efficiency index (CEI), number of calvings (NC), lifetime milk production (LMP), total lactation periods (TLP), lifetime daily milk production (LDMP), and total dry periods (TDP). The least squares means of LS, PL, CEI and NC were 96.3±1.80 months, 73.2±2.80 months, 64.9±0.008 % and 4.3±0.12 calving for Shami cows in respective order. The corresponding figures for Holstein cows were 66.1±1.81 months, 43.5±2.81 months, 56.4±0.012 % and 3.5±0.19 calving, respectively. The means of LMP, TLP, LDMP and TDP were 7713±563.38 kg, 787±33.43 days, 2.7±0.13 kg and 890±25.55 days for Shami cows and 14406±875.77 kg, 1049±51.96 days, 5.9±0.20 kg and 275±39.72 days for Hol-stein, respectively.The effect of breed was highly significant (P<0.01) on all studied traits. Cows for both breeds with AFC less than 24 months had more PL and NC. Also, cows with the highest average FLMY had the highest LMP, LDMP and TLP. It could be concluded that under the subtropical condi-tions, Shami cows exhibit superiority for longevity traits compared to Holstein ones.

Genetic analysis of longevity and their associations with fertility traits in Holstein cattle

The increase of longevity is intended to reduce involuntary culling rates, not extend the life span, and it reflects the ability of animals to successfully cope with the environment and disease during production. Sire model, animal model and repeatability animal models were used to estimate the (co) variance components of longevity and fertility traits. Six longevity and thirteen fertility traits were analysed, including herd life (HL), productive life (PL), number of days between first calving and the end of first lactation or culling (L1); number of days between first calving and the end of the second lactation or culling (L2); number of days between first calving and the end of the third lactation or culling (L3); number of days between first calving and the end of the fourth lactation or culling (L4); age at first service, age at first calving (AFC), the interval from first to last inseminations in heifer (IFLh), conception rate of first insemination in heifer, days open (DO), calving interval, gestation length, interval from calving to first insemination (ICF), interval from first to last inseminations in cow (IFLc), conception rate of first insemination in cow, calving ease (CE), birth weight, and calf survival. The estimated heritabilities (±SE) were 0.018 (±0.003), 0.015 (±0.003), 0.049 (±0.004), 0.025 (±0.003), 0.009 (±0.002) and 0.011 (±0.002) for HL, PL, L1, L2, L3 and L4, respectively. Strong correlations were appeared in HL and PL; the genetic and phenotypic correlation coefficients were 0.998 and 0.985, respectively. There were high genetic and phenotypic correlations which were observed in L1 and L2, L2 and L3, L3 and L4, respectively. All fertility traits of heifer showed medium to high heritability, while the cow showed low heritability. All heifer fertility traits had low genetic associations with longevity traits, ranging from −0.018 (L2 and IFLh) to 0.257 (L3 and AFC). Most of the fertility traits showed negative correlations with longevity traits in different parities, and we recommend DO, ICF, IFLc and CE as indirect indicators of longevity traits in dairy cows, but we also need to take into account the differences between parities.

Genomic and Phenotypic Udder Evaluation for Dairy Cattle Selection: A Review.

The traditional point of view regarding dairy cattle selection has been challenged by recent genomic studies indicating that livestock productivity prediction can be redefined based on the evaluation of genomic and phenotypic data. Several studies that included different genomic-derived traits only indicated that interactions among them or even with conventional phenotypic evaluation criteria require further elucidation. Unfortunately, certain genomic and phenotypic-derived traits have been shown to be secondary factors influencing dairy production. Thus, these factors, as well as evaluation criteria, need to be defined. Owing to the variety of genomic and phenotypic udder-derived traits which may affect the modern dairy cow functionality and conformation, a definition of currently important traits in the broad sense is indicated. This is essential for cattle productivity and dairy sustainability. The main objective of the present review is to elucidate the possible relationships among genomic and phenotypic udder evaluation characteristics to define the most relevant traits related to selection for function and conformation in dairy cattle. This review aims to examine the potential impact of various udder-related evaluation criteria on dairy cattle productivity and explore how to mitigate the adverse effects of compromised udder conformation and functionality. Specifically, we will consider the implications for udder health, welfare, longevity, and production-derived traits. Subsequently, we will address several concerns covering the application of genomic and phenotypic evaluation criteria with emphasis on udder-related traits in dairy cattle selection as well as its evolution from origins to the present and future prospects.

Impatiens namchabarwensis is distinct from I. arguta

Impatiens namchabarwensis was described as a new species in 2005 by Morgan et al. As already mentioned in the species description, I. namchabarwensis is morphologically similar to I. arguta and the small range of I. namchabarwensis in the eastern Himalaya is nested within the large, Himalayan range of I. arguta. Therefore, I. namchabarwensis has frequently been treated as synonym of I. arguta (e.g. in the Flora of China). We compared plant longevity, flower morphology and other functional floral traits and analyzed the differences between the two taxa. We found that I. namchabarwensis is a short‐lived perennial reaching maximally three years whereas I. arguta is a long‐lived perennial. Further, the floral traits of the two species differ significantly. These differences are also reflected in the main pollinator groups of the two species, which are hawk moths for I. namchabarwensis and bumblebees for I. arguta. Hence, we follow the argumentation of Morgan et al. and conclude that I. namchabarwensis and I. arguta are two distinct species.

Control of Mycobacterium avium subsp. paratuberculosis load within infected bovine monocyte-derived macrophages is associated with host genetics.

The genetic loci influencing individual resistance to Mycobacterium avium subsp. paratuberculosis (MAP) infection are still largely unknown. In the current study, we searched for genetic loci associated with resistance to MAP infection by evaluating the performance of monocyte-derived macrophages (MDMs) isolated from the peripheral blood of 75 healthy Holsteins cows and infected ex vivo with MAP. Bacterial load (log colony-forming units, log CFUs) within MDMs was quantified at 2h and 7 days p. i. using a BACTEC MGIT 960 instrument. In addition, the expression levels of some genes with important roles in the innate immune response including epiregulin (EREG), complement component C3 (C3), galectin-9 (Gal9), and nitric oxide (NO-) were measured in the supernatant of the infected cells. DNA from peripheral blood samples of the animals included in the study was isolated and genotyped with the EuroG MD bead Chip (44,779 single nucleotide-polymorphisms, SNPs). Linear mixed models were used to calculate the heritability (h2 ) estimates for each indicator of MDM performance, MAP load within MDMs and EREG, C3, Gal9, and NO-expression. After performing a genome-wide association study, the only phenotypes that showed SNPs with a significant association were the bacterial load within MDMs at 2h (h2 = 0. 87) and 7 days (h2 = 0.83) p.i. A total of 6 SNPs, 5 candidate genes, and one microRNA on the Bos taurus chromosomes BTA2, BTA17, BTA18, and BTA21 were associated with MAP load at 2h p.i. Overlap was seen in two SNPs associated with the log CFUs at 2h and 7d p.i. The identified SNPs had negative regression coefficients, and were, therefore, associated with a low bacterial load within MDMs. Some of the identified SNPs were located within QTLs previously associated with longevity, reproductive, and udder health traits. Some of the identified candidate genes; Oxysterol Binding Protein Like 6, Cysteine and Serine Rich Nuclear Protein 3, and the Coiled-Coil Domain Containing 92 regulate cellular cholesterol trafficking and efflux, apoptosis, and interferon production, respectively. Taken together, our results define a heritable and distinct immunogenetic profile in MAP-infected macrophages designed to limit bacterial load early after infection.

Genetic Parameters for Functional Longevity, Type Traits, and Production in the Serbian Holstein.

In this study, the authors focused on the evaluation of the genetic parameters of longevity, milk yield traits, and type traits in dairy cattle populations in the Republic of Serbia. The total dataset used consisted of production records and pedigree data for 32,512 Holstein cows that calved from 1981 to 2015. The animal model was applied to determine the variance and covariance components and genetic parameters of the analyzed traits by applying the restricted maximum likelihood (REML) approach and using the programs VCE6 and PEST. The heritability of longevity traits was estimated using the Survival Kit V6.0 software package. Variance and covariance were estimated for five production traits: milk yield (MY), fat yield (FY), protein yield (PY), milk fat content (MC), and protein content (PC), and three longevity traits: length of productive life (LPL), lifetime milk yield (LMY), and the number of lactations achieved (NL) as well as for 18 standard type traits. Heritabilities for the milk, fat, and protein yield traits were 0.20 (MY), 0.15 (FY), and 0.19 (PY), respectively. The estimated coefficients of heritability for the longevity traits were higher when using the Weibull proportional hazards model compared to the traditional linear methods and ranged from 0.08 for NL to 0.10 for LPL. Heritability values for the type traits varied from a low of 0.10 (RLSsv-rear legs set-side view) to medium values of 0.32 (ST-stature). Genetic correlations were found between MY and the following longevity traits: LPL, LMY, and NL with values of -0.18, -0.11, and -0.09, respectively. Genetic correlations were found between MY and a number of linear type traits and varied from 0.02 (between MY and RUH-rear udder height) to 0.28 (between MY and FUA-fore udder attachment). Genetic correlations between the 18 investigated type traits ranged from -0.33 between TL (top line) and RTP (rear teats position) to 0.71 between AN (angularity) and RUH (rear udder height). Genetic correlations between most linear type traits and longevity traits (LPL, LMY, and NL) were generally negative and very low. The highest positive genetic correlation was found between UD and LPL (rxy = 0.38).

A Single Nucleotide Variant in the PPARγ-homolog Eip75B Affects Fecundity in Drosophila.

Single nucleotide polymorphisms are the most common type of genetic variation, but how these variants contribute to the adaptation of complex phenotypes is largely unknown. Experimental evolution and genome-wide association studies have demonstrated that variation in the PPARγ-homolog Eip75B has associated with longevity and life-history differences in the fruit fly Drosophila melanogaster. Using RNAi knockdown, we first demonstrate that reduced expression of Eip75B in adult flies affects lifespan, egg-laying rate, and egg volume. We then tested the effects of a naturally occurring SNP within a cis-regulatory domain of Eip75B by applying two complementary approaches: a Mendelian randomization approach using lines of the Drosophila Genetic Reference Panel, and allelic replacement using precise CRISPR/Cas9-induced genome editing. Our experiments reveal that this natural polymorphism has a significant pleiotropic effect on fecundity and egg-to-adult viability, but not on longevity or other life-history traits. Our results provide a rare functional validation at the nucleotide level and identify a natural allelic variant affecting fitness and life-history adaptation.

Mothers of small-bodied children and fathers of vigorous sons live longer.

Life-history traits (traits directly related to survival and reproduction) co-evolve and materialize through physiology and behavior. Accordingly, lifespan can be hypothesized as a potentially informative marker of life-history speed that subsumes the impact of diverse morphometric and behavioral traits. We examined associations between parental longevity and various anthropometric traits in a sample of 4,000-11,000 Estonian children in the middle of the 20th century. The offspring phenotype was used as a proxy measure of parental genotype, so that covariation between offspring traits and parental longevity (defined as belonging to the 90th percentile of lifespan) could be used to characterize the aggregation between longevity and anthropometric traits. We predicted that larger linear dimensions of offspring associate with increased parental longevity and that testosterone-dependent traits associate with reduced paternal longevity. Twelve of 16 offspring traits were associated with mothers' longevity, while three traits (rate of sexual maturation of daughters and grip strength and lung capacity of sons) robustly predicted fathers' longevity. Contrary to predictions, mothers of children with small bodily dimensions lived longer, and paternal longevity was not linearly associated with their children's body size (or testosterone-related traits). Our study thus failed to find evidence that high somatic investment into brain and body growth clusters with a long lifespan across generations, and/or that such associations can be detected on the basis of inter-generational phenotypic correlations.

Effect of grazing system on lifetime performance and longevity of Holstein and Slovak Spotted cattle

The objective of the study was to analyse longevity and lifetime performance traits in dependence on access to grazing (G). Data of Holstein and Slovak Spotted dairy cows (143,566 and 30,412 heads culled between 2006 and 2019) were included. Within each breed, three groups of cows were considered: (1) cows not grazed throughout their entire life, (2) cows seasonally grazed as heifers (in summer), (3) cows seasonally grazed throughout their entire life (in summer). Eight (four longevity and four lifetime milk performance) traits were analysed. General Linear Model with fixed factors: G, herd nested within G, culling year, and cow’s age at first calving as covariate was applied. Cows of group (1) had the highest 305-day milk yield: 8,005.0±7.1 kg (Holstein) and 5,985.3±13.0 kg (Slovak Spotted) and lifetime milk yield: 18,408.5±59.4 kg (Holstein) and 18,237.2±129.1 kg (Slovak Spotted). Holstein cows of group (1) had the highest length of productive life (882.4±2.5 days) and number of lactations (2.37±0.01). The highest length of productive life (1,298.0±16.4 days) and number of lactations (3.46±0.04) were found in Slovak Spotted cows of group (3). The best lifetime performance (regardless of breed) was expected in cows not grazed; whereas, the best longevity traits were expected in Slovak Spotted cows seasonally grazed throughout their lives. Surprisingly, in Holstein cows, the best longevity traits were found in animals that were not grazed. This suggests that the living conditions of housed Holstein cows did not negatively affect their longevity.

Molecular characterization of seed longevity in soybean [Glycine max (L.) Merrill] using SSR markers

Soybean is the most important oilseed in the tropical and subtropical parts of the world unfortunately has poor competence for seed longevity. It?s strongly affected by environment (Temperature and RH) during seed formation, harvest and storage. Tagging of seed longevity associated markers in the crosses (Birsa Soya1 ? DS-228) which are good and poor storer genotypes resp. by using 26 SSR primers in genotypes contrasting for these traits in soybean. The polymorphism was observed between genotypes differing for seed longevity trait for six primer pairs, viz; Sat_162, Satt632, Sat_202, Satt523, Satt184 and Satt460, among them seed coat hardiness QTL, SCH 1-2 linked Satt632 amplified distinct markers. Bulked segregant analysis was carried out by using SSR markers in segregating 93 F2 populations. The Satt632-237 bp marker was further validated in individual F2 plant population. The genotype, Birsa Soya1 and it segregants Satt632-237 bp marker was found to be closely associated with high seed longevity in soybean. Hence, the primer Satt632 is impending marker for marker assisted breeding for high seed longevity marker to be linked to seed coat hardiness loci qSCH1-2 like gene present on chromosome A2. Seed longevity trait is governed by one or few gene with observed segregation ratio of 3.65:1 as against expected segregated ratio 3:1. Candidate gene analysis at qSCH1-2 loci, indicated for role of either a brassinosteriod regulated protein or pentatricopeptide repeat gene to regulate seed longevity.

Effect of Seed Coat Characteristics on Seed Quality in Soybean [Glycine max (L) Merrill] Genotypes with Contrasting Seed Longevity Traits

Background: The soybean seed is highly susceptible to field weathering and mechanical damages which adversely affect its longevity. Non-availability of good quality seed and post-harvest maintenance of prescribed level of seed germination and vigour until immediate planting season is the major constraint for soybean seed production. In soybean, the seed coat is one of the main determinants of seed germination, vigour and longevity potentials. Methods: In view of the same, the present study was conducted during 2015-16 and 2016-17 on 24 soybean genotypes having contrasting seed longevity traits. Freshly harvested seeds were stored for eight months under laboratory ambient environment (25±2°C and 65±5% RH) for evaluation of seed coat properties which are helpful in protecting the seeds from mechanical damage during pre- and post-harvest operations and study its relation with the seed quality. Result: Black, small-seeded soybean genotypes with white hilum were found to be better storers. Thick seed coat and higher seed coat (%) with more and uniform hours glass cells attributed to better seed quality for these genotypes. Parameters like seed coat (%), lignin content and mechanical strength remained unchanged during eight months laboratory ambient storage. Based on these observations, genotypes AMSS-34 and G-2265 were identified as better genotypes, which may be exploited in soybean crop improvement programme.

Assessment of the genetic parameters and breeding value of bulls-producers of the Ukrainian black speckled milky breed by the main characteristics

Evaluation and selection of breeding bulls based on economically important characteristics is the main tool in modern systems of genetic improvement of dairy cattle. The purpose of the study was to analyse the influence of environmental and genetic factors on the traits of milk productivity, reproduction, productive longevity, and the difficulty of calving, to assess the genetic parameters and breeding value of breeding bulls based on these traits. The research material was data on the indicators of productivity, reproduction, and productive longevity of cows of the Ukrainian black speckled milky breed of the agricultural cooperative “Vostok” of the Kharkiv region. A multidimensional linear-threshold model was used to calculate genetic parameters (heritability coefficients and genetic correlations) and breeding values of breeding bulls. A probable phenotypic negative association was identified between calving difficulty and milk yield for 305 days (r= -0.2244±0.0266, P>0.999); an increase in calving difficulty by 1 point leads to a decrease in milk yield for 305 days of lactation by 1281.0 kg. Calculated estimates of genetic correlation indicate the presence of a fairly high relationship between milk yield for 305 days of lactation and the service period (over +0.5), a negative relationship between the service period and productive longevity (about -0.37), and a positive relationship between the service period and calving difficulty (about +0.26). This data indicates the presence of genetic antagonism between milk productivity and the level of reproduction of dairy cows, the negative impact of the extended service period on the length of stay of cows in the dairy herd, and the impact of calving difficulty on the deterioration of cow fertility. Estimates of the breeding value of breeding bulls by milk yield, service period, productive longevity, and calving difficulty were calculated. The results obtained indicate the expediency of including traits of reproduction, productive longevity, and difficulty of calving cows in the breeding index, which is used to evaluate and select bulls-producers of the Ukrainian black speckled milky breed

Longevity, productive and reproductive traits of cows of Black-and-White breed

The intensification of dairy cattle breeding and the crossbreeding of many breeds of cattle with Holstein breed has led to the premature culling of cows from the herd and currently in Russia the longevity of dairy cows does not exceed 2,6–3,6 calving, i. e. the animals do not live up to the period of maximum milk productivity and payback for the cost of rearing heifers. When studying the issue of productive longevity of dairy cows, the study of its association with the level of milk productivity and reproductive traits is of particular interest. Dairy productivity and reproductive function in cows are interrelated and are the main factors determining the profi tability of the dairy cattle industry. The purpose of the research was to analyze the longevity, productive and reproductive traits of cows of Black-and-White breed in the Vologda region. It was found as a result of the research that the longest duration of economic use (3,39 lactations and 1569 days) and the lifetime productivity of milk the basic fat content (27 104 kg) had animals with a blood content of Holstein breed of 26 to 49 %. Along with this, the largest number of calves (4,13 heads) was obtained from animals with this genotype during the period of economic use. Analysis of the infl uence of lifetime productivity of dams on the productive longevity and reproductive traits of their daughters showed that a longer period of economic use (985 days), the largest number of completed lactation (2,32) and higher lifetime productivity (21 574 kg) was noted in daughters of cows with a lifetime milk yield of 35 000–44 999 kg. Animals that optimally combine the parameters of productive, reproductive traits and longevity have been identified, and the economic efficiency of their use has been determined in the paper.

Polar day syndrome: differences in growth, photosynthetic traits and sink-size patterns between northern and southern Finnish silver birch (Betula pendula Roth) provenances in native and non-native photoperiods.

Continuous light (CL) is available throughout the polar day for plants in the Arctic during the growing season, whereas provenances of the same species experience a very different environment with non-CL (NCL) just a few latitudes to the south. Both provenances need to acclimate to climate warming, yet we lack comprehensive understanding of how their growth, photosynthesis and leaf traits differ. Further, the provenances presumably have morphological and physiological adaptations to their native environments and therefore differ in response to photoperiod. We tested the height growth, leaf longevity, biomass accumulation, biomass allocation and rates of gas exchange of northern (67°N) and southern (61°N) Finnish silver birch (Betula pendula Roth) origins in CL- and NCL-treatments in a 4-month chamber experiment. Irrespective of photoperiod, 67°N had higher area-based photosynthetic rate (Anet), stomatal conductance (gs) and relative height growth rate (RGR), but lower stomatal density and fewer branches and leaves than 61°N. Photoperiod affected height growth cessation, biomass and photosynthetic traits, whereas leaf longevity and many leaf functional traits remained unchanged. In CL, both provenances had lower gs, higher RGR, increased shoot:root ratio and increased sink sizes (more branching, more leaves, increased total plant dry weight) compared with NCL. In NCL, 67°N ceased height growth earlier than in CL, which altered biomass accumulation and distribution patterns. Northern conditions impose challenges for plant growth and physiology. Whether a provenance inhabits and is adapted to an area with or without CL can also affect its response to the changing climate. Northern birches may have adapted to CL and the short growing season with a 'polar day syndrome' of traits, including relatively high gas exchange rates with low leaf biomass and growth traits that are mainly limited by the environment and the earlier growth cessation (to avoid frost damage).

Genetic parameters for dairy calf and replacement heifer wellness traits and their association with cow longevity and health indicators in Holstein cattle

High mortality and involuntary culling rates cause great economic losses to the worldwide dairy cattle industry. However, there is low emphasis on wellness traits in replacement animals (dairy calves and replacement heifers) during their development stages in modern dairy cattle breeding programs. Therefore, the main objectives of this study were to estimate genetic parameters of wellness traits in replacement cattle (replacement wellness traits) and obtain their genetic correlations with 12 cow health and longevity traits in the Chinese Holstein population. Seven replacement wellness traits were analyzed, including birth weight, survival from 3 to 60 d (Sur1), survival from 61 to 365 d (Sur2), survival from 366 d to the first calving (Sur3), calf diarrhea, calf pneumonia, and calf serum total protein (STP). Single and bivariate animal models were employed to estimate (co)variance components using the data from 189,980 Holstein cattle. The genetic correlations between replacement wellness traits and cow longevity, health traits were calculated by employing bivariate models, including 6 longevity traits and 6 health traits (clinical mastitis, metritis, ketosis, displaced abomasum, milk fever, and hoof health or hoof disease). The estimated heritabilities (± SE) were 0.335 (± 0.008), 0.088 (± 0.005), 0.166 (± 0.006), 0.102 (±0 .006), 0.048 (± 0.003), 0.063 (± 0.004), and 0.170 (± 0.019) for birth weight, Sur1, Sur2, Sur3, pneumonia, diarrhea, and STP, respectively. The majority of the genetic correlations among the 7 replacement wellness traits were negligible. The genetic correlations among Sur1, Sur2, and Sur3 ranged from 0.112 (Sur1 and Sur3) to 0.445 (Sur1 and Sur2) when fitting a linear model (estimates in the observed scale), and from 0.560 (Sur1 and Sur3) to 0.773 (Sur1 and Sur2) when fitting a threshold model (estimates in the liability scale). The genetic correlations between replacement wellness and cow longevity were low (absolute value lower than 0.30), but some of them were significantly different from zero. Compared with other replacement wellness traits, Sur3 and STP had relatively high genetic correlations with cow longevity. Replacement wellness traits are heritable and can be improved through direct genetic and genomic selection. The results from the current study will contribute for better balancing dairy cattle breeding goals to genetically improve dairy cattle wellness in the period from birth to first calving.