Productivity of crosses based on prolific breeds of sheep

Jakubec, V.

doi:10.1016/0301-6226(77)90007-0

Cited by 19 publications

(9 citation statements)

References 14 publications

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“…Heterosis in humans has been proposed, sometimes controversially, to affect multiple phenotypes including attractiveness [1], IQ [2,3], and height [4][5][6]. In agricultural settings, there are numerous examples in which heterosis has been harnessed to create more productive and more uniform products including livestock [7][8][9][10][11] and crop plants (reviewed in [12][13][14][15][16][17][18][19]). Heterosis can also be captured and fixed through the process of polyploidization which is common in the plant kingdom (reviewed in [13,14,20]).…”

Section: Introductionmentioning

confidence: 99%

Heterosis: Many Genes, Many Mechanisms—End the Search for an Undiscovered Unifying Theory

Kaeppler

2012

ISRN Botany

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Heterosis is the increase in vigor that is observed in progenies of matings of diverse individuals from different species, isolated populations, or selected strains within species or populations. Heterosis has been of immense economic value in agriculture and has important implications regarding the fitness and fecundity of individuals in natural populations. Genetic models based on complementation of deleterious alleles, especially in the context of linkage and epistasis, are consistent with many observed manifestations of heterosis. The search for the genes and alleles that underlie heterosis, as well as for broader allele-independent, genomewide mechanisms, has encompassed many species and systems. Common themes across these studies indicate that sequence diversity is necessary but not sufficient to produce heterotic phenotypes, and that the molecular pathways that produce heterosis involve chromatin modification, transcriptional control, translation and protein processing, and interactions between and within developmental and biochemical pathways. Taken together, there are many and diverse molecular mechanisms that translate DNA into phenotype, and it is the combination of all these mechanisms across many genes that produce heterosis in complex traits.

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Section: Introductionmentioning

confidence: 99%

Heterosis: Many Genes, Many Mechanisms—End the Search for an Undiscovered Unifying Theory

Kaeppler

2012

ISRN Botany

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“…The availability of breeds with performance characteristics markedly different from traditional indigenous breeds, especially in reproduction, has renewed interest in breed evaluation and crossing experimentation in many countries. Extensive summaries have been reported for performance of Finnsheep in Finland and elsewhere (Maijala and Osterberg, 1977), Finnsheep crosses in the United States (Dickerson, 1977), prolific breed crosses in Europe (Jakubec, 1977) and from French experiments, mainly involving the Romanov and its crosses (Ricordeau et al, 1978). In all reports, the prolific • indigenous F1 crossbred ewes have markedly excelled indigenous pure breeds and their crosses in early sexual development, fertility and litter size.…”

Section: Introductionmentioning

confidence: 99%

Lamb Production and Its Components in Pure Breeds and Composite Lines. II. Breed Effects and Heterosis

Fogarty

Dickerson

Young

1984

Journal of Animal Science

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Ewe performance was compared for five pure breeds of sheep (Finnsheep, F; Rambouillet, R; Dorset, D; Targhee, T; Suffolk, S) and the crosses in development of two maternal composite lines (C1 = 1/2F1/4R1/4D and C2 = 1/2F1/4T1/4S). The data involved 10,959 breeding season records of 4,219 ewes by 412 sires. Ewe production and the components (fertility, litter size, neonatal and preweaning lamb survival and mean lamb weaning weight) were adjusted for age and standardized across season of lambing and years. The D and F ewes produced more weight of lamb/ewe exposed than R, S and T ewes because of higher D and F fertility, higher D lamb survival and larger F litters. First cross and inter se generations of C1 and C2 ewes averaged 17 to 27% higher fertility than the parental mean. Litter size averaged about one lamb higher for F than for other pure breeds, but only slightly higher for C1 and C2 than for the mean of F and other breeds. Lower neonatal survival for F than for other breeds and crosses was associated with the larger F litters and with 2 to 8% positive heterosis in the crosses. Preweaning survival of suckled and nursery lambs was low for F and S and positive heterosis ranged from 9 to 19% in crosses. Mean lamb weaning weights were highest for S, lowest for F, with little heterosis in crosses. Crossbred ewes reared .3 to .4 more lambs than mean for parental pure breeds. Heterosis in C1 and C2 ranged from 11 to 28% for lambs born, 27 to 43% for lambs weaned and 29 to 44% for weight of lamb weaned/ewe exposed. Decline in heterosis with inter se mating of crosses was no greater than expected from the reduction in predicted heterozygosity.

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“…Comprehensive studies on microsatellite variation and genetic diversity in North European sheep breeds have been reported on in recent years (Tapio et al, 2005a and2005b;Tapio, 2006;Eythó rsdó ttir, 2007). These and other studies have shown clearly several common characteristics of the North European short-tailed breeds, in addition to the short tail, such as a wide range of colour patterns, dual-coated wool, robustness and prolificacy (Adalsteinsson, 1970;Jakubec 1977;Maijala and Ö sterberg, 1977;Ricordeau et al, 1978;Finnsheep, 1988;Fahmy, 1989;Kantanen, 2003;Niclasen, 2007). Both polled and horned sheep are found in these breeds -in some cases, sex linked, and even fourhornedness, is still known in a few of them (National Sheep Association, 1998;Dy´rmundsson, 2005).…”

Section: Breed Characteristicsmentioning

confidence: 52%

“…The best-known breeds of this group outside Northern Europe are the Finnsheep and the Romanov, which have been exported to several countries in the world where their genetic merits, especially prolificacy, have been utilized through crossbreeding with local sheep (Jakubec, 1977;Maijala and Ö sterberg, 1977;Ricordeau et al, 1978;Finnsheep, 1988;Fahmy, 1989;Thomas, 2010). Thus, they have played an important role in the production of some new synthetic/ composite breeds in several countries through hybridization.…”

Section: Breed Characteristicsmentioning

confidence: 99%

North European short-tailed breeds of sheep: a review

Dýrmundsson

Niżnikowski

2010

Animal

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The short-tailed sheep, native of an area stretching from Russia to Iceland, are generally considered a primitive type. These robust northern sheep seem to have been spread by Norse vikings to several countries in this area from the late eighth century to the middle of the eleventh century AD. They have several common characteristics in addition to the fluke-shaped and tapered short tail, such as a wide range of colour patterns, dual-coated wool and the ability to thrive under harsh environmental conditions, often in isolated marginal areas. While 34 short-tailed breeds of North European origin can still be identified, it is clear that their population sizes have declined in most cases and several of them are now rare and endangered. Although these breeds have mainly been confined to certain localities, some of them have gained considerable distribution due to their genetic merits, such as prolificacy. Of these, the Finnsheep and the Romanov are best known being exported to several countries in the world where their genetic material has been utilized through crossbreeding with local sheep. This has resulted in the production of some new synthetic breeds. Meat is now generally the main product of the North European short-tailed breeds and their crossbreds, whereas wool, skins and milk are normally regarded as byproducts, yet of considerable economic importance in some cases. Such breeds have clearly a role to play in sustainable grassland-based production systems in the future.

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Productivity of crosses based on prolific breeds of sheep

Cited by 19 publications

References 14 publications

Heterosis: Many Genes, Many Mechanisms—End the Search for an Undiscovered Unifying Theory

Heterosis: Many Genes, Many Mechanisms—End the Search for an Undiscovered Unifying Theory

Lamb Production and Its Components in Pure Breeds and Composite Lines. II. Breed Effects and Heterosis

North European short-tailed breeds of sheep: a review

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