Evaluation of sheep genetic resources in North America: Ewe productivity of purebred, crossbred and synthetic populations

2008 ◽  
Vol 88 (3) ◽  
pp. 399-408 ◽  
Author(s):  
J. N. B. Shrestha ◽  
W. J. Boylan ◽  
W. E. Rempel
Keyword(s):  
Genetic Variation ◽  
North America ◽  
Genetic Resources ◽  
Reproductive Performance ◽  
Poor Performance ◽  
Reciprocal Crosses ◽  
Genetic Types ◽  
Synthetic Populations ◽  
Lamb Survival ◽  
Fleece Weight

Ewe productivity from divergent genetic types of established purebreds e.g., Dorset (D), Lincoln (L), Rambouillet (Ra), Suffolk (Su) and Targhee (T); fecund-type breeds e.g., Finnsheep (F) and Romanov (Ro) breeds, and their reciprocal crosses; the Outaouais (O) and Rideau (R) Arcott breeds and their reciprocal crosses; and Synthetic I (½ F, ½ L), Synthetic II (½ D, ½ Ra) and Synthetic III (¼ F, ¼ L, ¼ D, ¼ Ra) populations were evaluated. Prolificacy, fecundity, ewe weight, grease fleece weight, wool grade, lamb survival and total lamb weights at birth, 30 d and 140 d per ewe lambing were considered jointly as a measure of ewe productivity. In general, fecund-type breed cross and Arcott breed cross were highest in productivity, the fecund-type breed, Arcott breed and synthetic populations were intermediate, in contrast the established breeds was lowest. Regardless of significantly heavier ewe and grease fleece weights, and superior wool grade of the established breeds, their poor performance can be attributed to lower prolificacy, fecundity and total lamb weights (P < 0.05). Within established breeds, the D, L, Ra and T breeds were comparable in productivity to the Su breed, but lower than the F breed (P < 0.05). The Ro breed surpassed the F breed because of significantly higher prolificacy and fecundity, and heavier ewe weight and total lamb weights, while grease fleece weight and wool grade were inconsistent. The F and Ro breeds were comparable to the Su breed despite significantly higher prolificacy and fecundity, in contrast to lighter ewe and grease fleece weights, lower wool grade, lamb survival, similar total lamb weights. Although the R breed produced significantly heavier grease fleece weight and total lamb weights than the O breed, both breeds were similar to the Su breed despite their significantly higher prolificacy and fecundity, in contrast to similar ewe weight, wool grade, lamb survival and total lamb weights, and lighter grease fleece weight. The O and R breeds were more productive than the F breed as a result of significantly heavier ewe weight, superior wool grade, higher lamb survival and heavier total lamb weights, despite their similar prolificacy, fecundity and grease fleece weight. Synthetic I and Synthetic III with Finnsheep lineage surpassed Synthetic II in productivity as a result of significantly higher prolificacy and fecundity, and heavier total lamb weights, despite similar ewe and grease fleece weights and inconsistent wool grade and lamb survival. At the same time, Synthetic I and Synthetic III were not only similar to the Su breed, but surpassed the F breed, whereas Synthetic II was similar to the Su breed and lower than the F breed. Finally, systematic crossbreeding and composite population of complementary fecund-type and established breeds achieved increased productivity from additive genetic variation and heterosis. Key words: Reproductive performance, ewe and grease fleece weights, total lamb weights, Arcotts, Finnsheep, Romanov, synthetic populations, established breeds

Evaluation of sheep genetic resources in North America: Lamb productivity of purebred, crossbred and synthetic populations

2008 ◽  
Vol 88 (3) ◽  
pp. 391-398 ◽  
Author(s):  
J. N. B. Shrestha ◽  
W. J. Boylan ◽  
W. E. Rempel
Keyword(s):  
North America ◽  
Genetic Resources ◽  
Key Words ◽  
North American ◽  
Reciprocal Crosses ◽  
Key Words Growth ◽  
Genetic Types ◽  
Synthetic Populations ◽  
Breed Crosses

Lamb weights and daily gains from divergent genetic types of established purebreds, e.g., Dorset (D), Lincoln (L), Rambouillet (Ra), Suffolk (Su) and Targhee (T), and fecund-type breeds, e.g., Finnsheep (F) and Romanov (Ro), their reciprocal crosses and Suffolk sired specific cross Su(F × Ro) were evaluated. Also evaluated were lambs of the Outaouais (O) and Rideau (R) Arcott breeds and their reciprocal crosses, in addition to Synthetic I (½ F, ½ L), Synthetic II (½ D, ½ Ra) and Synthetic III (¼ F, ¼ L, ¼ D, ¼ Ra) populations. The established purebreds produced heavier lambs at birth and weaning, Arcott breed crosses gained weight more rapidly resulting in heavier lambs at 140 d, and fecund-type breeds produced lighter lambs (P < 0.05). In general, daily gains and lamb weights of all genetic types were similar, except that fecund-type breeds produced significantly lighter lambs. Lamb weights of T were most at birth, and Su at weaning and 140 d, while F lambs weighed the least (P < 0.05). Within established purebreds, Su weighed the most and D weighed the least, while L, Ra and T lambs were intermediate. Daily gains including weaning and 140-d weights of F and R cross lambs benefited from 7–9% heterosis, while the Arcott breed cross lambs not only benefited from 5–8% heterosis, but were comparable with Su lambs. At the same time, lamb performance of Su(F × Ro) was similar to the average of their parental breeds. Lambs of synthetic populations relative to the average of their respective parental breeds weighed 8–24% more at 140 d, suggesting heterosis retention. Key words: Growth, North American breeds, Finnsheep, Romanov, Arcotts, synthetic populations

Variation in reproduction and production of Poll Dorset ewes

1994 ◽  
Vol 45 (2) ◽  
pp. 415 ◽  
Author(s):  
DG Hall ◽  
AR Gilmour ◽  
NM Fogarty
Keyword(s):  
Litter Size ◽  
Environmental Effects ◽  
Reproductive Performance ◽  
Reproductive Traits ◽  
Late Summer ◽  
Reproductive History ◽  
Reproduction Traits ◽  
Lamb Survival ◽  
Fleece Weight ◽  
One Year

Poll Dorset ewes were joined to Booroola Merino (n = 22) or Trangie Fertility Merino (n = 26) rams in single sire joinings during late summer/autumn of 1978, 1979, 1980 and 1981. Rams were changed each year and there were 1678 individual ewe joinings. A maximum of 527 ewes were used in any one year, and they represented 14 studs and varied in age, reproductive history and liveweight. The traits, litter size, maternal lamb survival, lambs weaned per ewe lambing and weight of lamb weaned per ewe lambing (kg at 100 days) were analysed for the effect of year, stud, age, lambs born and ewe liveweight. Litter size averaged 1-37, maternal lamb survival 0.70, and number of lambs weaned per ewe was 0.94. There were large variations in the reproductive traits due to year and stud and lesser effects due to age. Each extra kilogram of ewe liveweight at joining increased litter size by 0.012 and weight of lamb weaned by 0.39 kg, but had no significant effect on maternal lamb survival or number of lambs weaned. Multiple-bearing ewes weaned 0.72 more lambs and 16 - 2 kg more lamb weight than single-bearing ewes. Lamb survival was similar for singleand multiple-bearing ewes. Greasy fleece weight averaged 2.2 kg ewe-' and single bearing ewes produced 0.19 kg/ewe more than multiple-bearing ewes. Dystocia caused 53% and starvation/mismothering/exposure caused 23% of lamb deaths; the proportion of deaths due to starvation/mismothering/exposure increased with increasing ewe joining liveweight. The large variation between studs in reproductive performance partly reflected genetic differences between Poll Dorset flocks which could be exploited. Estimates of heritabilities ranged from 0.06 to 0.14 � 0.10 for the reproductive traits and were 0.10 � 0.12 for ewe liveweight and 0.16 � 0.20 for greasy fleece weight. However much of the between stud variation may also have arisen from early environmental effects. Estimates of repeatability ranged from 0.06 to 0.l5 � 0 05 for reproduction traits and were 0.44 � 0.06 for ewe liveweight at joining and 0.56 � 0.08 for greasy fleece weight.

Evaluation of sheep genetic resources in North America: Milk production and composition of purebred, crossbred and synthetic populations

2008 ◽  
Vol 88 (4) ◽  
pp. 569-576 ◽  
Author(s):  
J. N. B. Shrestha ◽  
W. J. Boylan ◽  
W. E. Rempel
Keyword(s):  
North America ◽  
Milk Production ◽  
Milk Yield ◽  
Sheep Breeds ◽  
Lactation Length ◽  
Genetic Types ◽  
Middle East Countries ◽  
Synthetic Populations ◽  
Sheep Production ◽  
Daily Milk Yield

Purebreds, crossbreds and synthetic populations of sheep in North America of divergent genetic types produced 47–103 litres of milk for 121–144 d, consistent with "non dairy-type" breeds; however, this was substantially less than the 200–330 kg of milk per lactation characteristic of "dairy" type breeds in Europe and the Middle East countries. Among established breeds, the Suffolk (Su) breed produced significantly more total and daily milk yield, respectively, for a longer lactation (79 litres and 589 mL for 139 d), followed by the Rambouillet (Ra), Targhee (T) and Dorset (D) breeds (60–62 litres and 422–542 mL for 120–132 d), while the Lincoln (L) breed produced significantly less (48 litres and 285 mL for 128 d). Among fecund-type breeds and their crosses, Finnsheep (F) and Romanov (Ro) breeds produced significantly less (50–55 litres and 425–463 mL, for 122–129 d), while Ro × F produced significantly more milk (91 litres and 744 mL for 126 d), followed by F × Ro (60 litres and 505 mL for 128 d). Among other crossbreds, F × Ra produced significantly more milk (66 litres and 434 mL for 136 d) followed by L × Ra, L × D, F × L, F × Ra (49–60 litres and 296–385 mL for 123–136 d), while Ra × D produced significantly less (47 litres and 245 mL for 121 d). Among multiple breed composite populations, the Outaouais (O) and Rideau (R) Arcott breeds and their crosses had the highest milk production, e.g., R and R × O produced significantly more milk (95–103 litres and 754–820 mL for 131–144 d) than O and O × R (74–80 litres and 621–693 mL for 124–142 d). Concurrently, Synthetic I (½ F, ½ L) produced significantly less (58 litres and 494 mL for 134 d), while Synthetic III (¼ F, ¼ L, ¼ D, ¼ Ra) produced significantly more milk (91 litres and 673 mL, P > 0.05, for 130 d), and Synthetic II (½ D, ½ Ra) was intermediate (74.8 litres and 621 mL for 129 d); however, lactation length was consistent. Sheep breeds in North America exhibited diversity that was substantial for milk yield, but negligible for lactation length, as well as fat, protein, lactose and solid-not-fat content. Lack of inherent potential for milk production continues to be a serious constraint towards development of commercial dairy sheep industry. In the absence of "dairy-type" breeds, superior milk production in the Rideau Arcott breed (with East Friesian lineage) and their crosses demonstrates considerable promise for further improvement, thus increasing the efficiency of sheep production. Key words: Milk yield and composition, sheep breeds, synthetic sheep, Arcott breeds

scholarly journals Caffeinated Coffee and Tea Consumption, Genetic Variation and Cognitive Function in the UK Biobank

2020 ◽  
Vol 150 (8) ◽  
pp. 2164-2174
Author(s):  
Marilyn C Cornelis ◽  
Sandra Weintraub ◽  
Martha Clare Morris
Keyword(s):  
Genetic Variation ◽  
Cognitive Function ◽  
Poor Performance ◽  
Sociodemographic Factors ◽  
Caffeine Intake ◽  
Tea Consumption ◽  
Uk Biobank ◽  
Trail Making ◽  
Caffeine Metabolism ◽  
The Uk

ABSTRACT Background Coffee and tea are the major contributors of caffeine in the diet. Evidence points to the premise that caffeine may benefit cognition. Objective We examined the associations of habitual regular coffee or tea and caffeine intake with cognitive function whilst additionally accounting for genetic variation in caffeine metabolism. Methods We included white participants aged 37–73 y from the UK Biobank who provided biological samples and completed touchscreen questionnaires regarding sociodemographic factors, medical history, lifestyle, and diet. Habitual caffeine-containing coffee and tea intake was self-reported in cups/day and used to estimate caffeine intake. Between 97,369 and 445,786 participants with data also completed ≥1 of 7 self-administered cognitive functioning tests using a touchscreen system (2006–2010) or on home computers (2014). Multivariable regressions were used to examine the association between coffee, tea, or caffeine intake and cognition test scores. We also tested interactions between coffee, tea, or caffeine intake and a genetic-based caffeine-metabolism score (CMS) on cognitive function. Results After multivariable adjustment, reaction time, Pairs Matching, Trail Making test B, and symbol digit substitution, performance significantly decreased with consumption of 1 or more cups of coffee (all tests P-trend &lt; 0.0001). Tea consumption was associated with poor performance on all tests (P-trend &lt; 0.0001). No statistically significant CMS × tea, CMS × coffee, or CMS × caffeine interactions were observed. Conclusions Our findings, based on the participants of the UK Biobank, provide little support for habitual consumption of regular coffee or tea and caffeine in improving cognitive function. On the contrary, we observed decrements in performance with intakes of these beverages which may be a result of confounding. Whether habitual caffeine intake affects cognitive function therefore remains to be tested.

scholarly journals Genetic studies revealed differences between European and North American populations of Calypogeia azurea

2016 ◽  
Vol 42 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Katarzyna Buczkowska ◽  
Alina Bączkiewicz ◽  
Patrycja Gonera
Keyword(s):  
Genetic Variation ◽  
North America ◽  
Genetic Distance ◽  
Gene Diversity ◽  
Oil Bodies ◽  
Genetic Studies ◽  
Isozyme Loci ◽  
The Mean ◽  
Different Parts ◽  
Nei's Genetic Distance

Abstract Calypogeia azurea, a widespread, subboreal-montane liverwort species, is one of a few representatives of the Calypogeia genus that are characterized by the occurrence of blue oil bodies. The aim of the study was to investigate the genetic variation and population structure of C. azurea originating from different parts of its distribution range (Europe and North America). Plants of C. azurea were compared with C. peruviana, another Calypogeia species with blue oil bodies. In general, 339 gametophytes from 15 populations of C. azurea were examined. Total gene diversity (HT) estimated on the basis of nine isozyme loci of C. azurea at the species level was 0.201. The mean Nei’s genetic distance between European populations was equal to 0.083, whereas the mean genetic distance between populations originating from Europe and North America was 0.413. The analysis of molecular variance (AMOVA) showed that 69% of C. azurea genetic variation was distributed among regions (Europe and North America), 15% - among populations within regions, and 16% - within populations. Our study revealed that C. azurea showed genetic diversity within its geographic distribution. All examined samples classified as C. azurea differed in respect of isozyme patterns from C. peruviana.

Knotweed Management Strategies in North America with the Advent of Widespread Hybrid Bohemian Knotweed, Regional Differences, and the Potential for Biocontrol Via the Psyllid Aphalara itadori Shinji

2016 ◽  
Vol 9 (1) ◽  
pp. 60-70 ◽  
Author(s):  
David R. Clements ◽  
Todd Larsen ◽  
Jennifer Grenz
Keyword(s):  
Biological Control ◽  
Invasive Species ◽  
Genetic Variation ◽  
North America ◽  
North American ◽  
Regional Differences ◽  
The United States ◽  
The North ◽  
Variable Nature ◽  
Available Resources

AbstractInvasive species with distributions that encompass much of the North American environment often demand a range of management approaches, for several key reasons. Firstly, the North American environment includes a large number of highly variable habitats in terms of climatic, edaphic, and landscape features. Secondly, these regional habitat differences are accentuated by jurisdictions within Canada and the United States, whereby approaches and available resources differ at local, regional, and national scales. Another important consideration is whether an invasive species or complex also possesses genetic variation. All three of these factors render the knotweed complex in North America a highly variable target for management. In this paper we review existing knowledge of the variable nature of knotweed species (Fallopia japonica (Houtt.) Ronse Decr., Fallopia sachalinensis (F. Schmidt ex Maxim) Ronse Decr., and Fallopia × bohemica, (Chrtek and Chrtková) J. P. Bailey in North America, and evaluate how herbicidal, mechanical and biological control measures must account for this genetic variation, as well as accounting for regional differences and the potential northward expansion of knotweed under climate change. The imminent release of the psyllid, Aphalara itadori Shinji as a biological control agent in North America must also navigate regional and genetic differences. Prior European experience dealing with the three knotweed species should prove useful, but additional research is needed to meet the emerging challenge posed by F. × bohemica in North America, including the possibility of glyphosate resistance. Managers also face challenges associated with posttreatment restoration measures. Furthermore, disparities in resources available to address knotweed management across the continent need to be addressed to contain the rapid spread of this highly persistent and adaptable species. Linking practitioners dealing with knotweed “on the ground” with academic research is a crucial step in the process of marshalling all available resources to reduce the rapidly spreading populations of knotweed.

scholarly journals Gene banks for wild and cultivated sunflower genetic resources

OCL ◽  
2020 ◽  
Vol 27 ◽  
pp. 9 ◽  
Author(s):  
Sreten Terzić ◽  
Marie-Claude Boniface ◽  
Laura Marek ◽  
Daniel Alvarez ◽  
Karin Baumann ◽  
...  
Keyword(s):  
North America ◽  
Genetic Resources ◽  
Helianthus Annuus ◽  
Inbred Lines ◽  
Wild Sunflower ◽  
Gene Banks ◽  
Breeding Programmes ◽  
Wild Accessions ◽  
Modern Breeding ◽  
Local Research

Modern breeding of sunflower (Helianthus annuus L.), which started 100 years ago, increased the number and the diversity of cultivated forms. In addition, for more than 50 years, wild sunflower and other Helianthus species have been collected in North America where they all originated. Collections of both cultivated and wild forms are maintained in gene banks in many countries where sunflower is an important crop, with some specificity according to the availability of germplasm and to local research and breeding programmes. Cultivated material includes land races, open pollinated varieties, synthetics and inbred lines. The majority of wild accessions are ecotypes of wild Helianthus annuus, but also 52 other species of Helianthus and a few related genera. The activities of three gene banks, in USA, France and Serbia, are described in detail, supplemented by data from seven other countries. Past and future uses of the genetic resources for environmental adaptation and breeding are discussed in relation to genomic and improved phenotypic knowledge of the cultivated and wild accessions available in the gene banks.

scholarly journals Reproductive performance of the Antarctic tardigrades, Acutuncus antarcticus (Eutardigrada: Hypsibiidae), revived after being frozen for over 30 years and of their offspring

2019 ◽  
Vol 188 (3) ◽  
pp. 839-847
Author(s):  
Megumu Tsujimoto ◽  
Hiroshi Kagoshima ◽  
Hiroshi Kanda ◽  
Kenichi Watanabe ◽  
Satoshi Imura
Keyword(s):  
Reproductive Performance ◽  
First Generation ◽  
Dna Analysis ◽  
Term Survival ◽  
Long Term Survival ◽  
Genetic Types ◽  
Genetic Sequences ◽  
The Antarctic ◽  
Generation Offspring

Abstract Studies on the long-term survival of animals often focus on the specific instance of survival of animals only, and descriptions of subsequent reproduction are generally not reported. In this study, we recorded the reproductive performance of the first-generation offspring of the resuscitated individual (SB-1) and the hatchling of the resuscitated egg (SB-3) of the Antarctic tardigrade, Acutuncus antarcticus, after being frozen for 30.5 years. By providing further detailed description of the reproduction of SB-1 and SB-3 after revival, and then comparing the reproductive performance with that of their first-generation offspring, the possible indications of the damage accrued during the long-term preservation in SB-1 and SB-3 were more specifically detected. Additionally, the DNA analysis revealed two distinctively different mitochondrial genetic sequences of A. antarcticus between the SB strains and the LSW strain. The observed differences in some of the reproductive parameters between the two genetic types suggested a possible relationship between the life-history traits and genetic type in the species A. antarcticus. Further experiments using the SB-1 and SB-3 strains reared for a long period to exclude the instant effect of preservation are expected to improve our understanding of the mechanisms underlying the long-term survival of animals.

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