Selection of Sires Originating From a Nucleus Breeding Unit for Use in a Commercial Dairy Population

Teepker, G.; Keller, David

doi:10.4141/cjas89-071

Cited by 6 publications

(4 citation statements)

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“…These schemes may be effective in organizing the breeding program, particularly when large-scale recording is lacking, for comparing animals under standard conditions ( Hinks, 1977 ; Smith, 1988 ). Many authors highlight advantages of these schemes, among them, the possibility of an initial genetic lift ( McDaniel and Cassel, 1981 ; Nicholas and Smith, 1983 ; Teepker and Keller, 1989 ). However, it is important to have a large base population, and to minimize the harmful effects of inbreeding and genetic drift ( Nicholas and Smith, 1983 ; Juga and Mäki-Tanila, 1987 ; Smith, 1988 ; Woolliams, 1989 ; Ruane, 1991 ; Ruane and Thompson, 1991 ).…”

Section: Introductionmentioning

confidence: 99%

“…Multiple ovulation and embryo transfer (MOET) allow an increase in family sizes, mainly in collateral relatives, enabling improvement of the nucleus-breeding scheme ( Nicholas and Smith, 1983 ; Colleau and Mocquot, 1989 ; McGuirk, 1989 ; Teepker and Keller, 1989 ; Woolliams and Wilmut, 1989 ). The use of embryo transfer allowed obtainment of groups of full-sisters and half-sisters, for a pre-assessment of young bulls entering the progeny test (PT) ( Smith and Ruane, 1987 ).…”

Section: Introductionmentioning

confidence: 99%

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The contribution of a MOET nucleus scheme for the improvement of Guzerá (Bos indicus) cattle for milk traits in Brazil

et al. 2022

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The Guzerá breed evolved from the introduction of breeds from India, mainly the Kankrej breed, into Brazilian livestock at the end of the 19th century. Guzerá adapted well to the climatic conditions of Brazil, where it is considered a dual-purpose breed and has been used for pasture-based beef, milk or dual-purpose production systems with the use of low-medium inputs. The importance of this genetic resource for milk production in tropical regions moved breeders to implement the National Breeding Program for the Improvement of Guzerá in 1994, based on both progeny testing and MOET nucleus schemes. We sought to evaluate the role of the MOET nucleus scheme in the phenotypic and genetic progress for milk traits in this breed. The initial database used in the present study consisted of 6,513 cows, daughters of 761 bulls. We performed genetic evaluations with different datasets using a linear mixed model in a single trait analysis, including the relationship matrix, in order to estimate breeding values. Inbreeding coefficients were also calculated using the relationship of descent between two parents. Annual phenotypic, genetic and inbreeding trends were obtained for each dataset, considering the genetic pathways of both the bull and the cow. The low genetic progress found for milk yield in the whole population (5.27 ± 0.30 kg/year) partially accounted for the dual-purpose selection goal, despite the higher genetic progress in the MOET nucleus (9.39 ± 0.79 kg/year). The inbreeding coefficient was minimized at the beginning of the breeding program based on the use of new lineages. Posteriorly, it started increasing again from 0.002 in 1991 to 0.008 in 2019. The results provided evidence of the significant contribution of the MOET nucleus scheme for the phenotypic and genetic progress of Guzerá breed for milk traits, as well as of the impact of the breeding program on the inbreeding coefficient rate in the early years. New strategies need to be designed for the Guzerá breed, to allow for greater improvement of milk traits and minimizing the rate of the inbreeding coefficient.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The contribution of a MOET nucleus scheme for the improvement of Guzerá (Bos indicus) cattle for milk traits in Brazil

et al. 2022

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“…Embryo transfer (ET) is now commonly used to produce AI sires from the top producing cows and proven bulls for the dairy industry [7]. As a perspective, the new genomic techniques presented are increasingly used for the selection of embryo donors, and genomic analysis has become essential for the selection of bull dams that will be used in embryo transfer [8].…”

Section: Introductionmentioning

confidence: 99%

Embryo Transfer

Ciornei¹

2022

Veterinary Medicine and Science

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Assisted reproductive technologies (ART) have made tremendous advances, in last years. Artificial insemination is a method for achieving slow genetic progress in populations of animals. Many large and small ruminants are bred by AI, and more than a half million embryos are transferred every year around the world. Most of the ruminants sires used for artificial insemination were derived from embryo transfer. Improvements of reproductive biotechnologies of controlling the estrous cycle and ovulation have resulted in more effective programs for AI, superovulation of donor, and the management of ET. In the ruminants, ET procedure is a timely alternative that can allow good conception rates to be obtained constant in a year. There have been great advances of this biotechnique with on aimed to intensify the genetic progress between generations of farm. The gains is possible with the development of advanced reproductive biotechnique. The best current strategy in applying biotechnology to farmers is to use AI with sexed semen, so farmers will enjoy and benefit. The use of ET together with cryopreserved sexed embryos has a very specific potential for donor replacement and genetic improvement of the herd. In this chapter, procedures of the MOET protocol were described step by step.

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“…Realistic designs of selection programs such as in nucleus breeding schemes have considered genotype by environment interactions [e.g., in sheep (D el B osque ‐G onzalez and K inghorn 1987); in pigs (M erks 1988); in dairy cattle (T eepker and K eller 1989)]. Open nucleus schemes may provide an operational procedure for achieving greater genetic progress than closed nucleus schemes.…”

Section: Introductionmentioning

confidence: 99%

The effects of genotype by environment interactions in dairy cattle open nucleus breeding schemes

Bondoc

Smith

1993

J Animal Breeding Genetics

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The evaluation of open nucleus breeding systems using progeny testing or adult or juvenile embryo transfer in the nucleus is extended to include genotype by environment interactions. Knowledge of the extent of such interactions can be used to design breeding schemes and to predict realistic rates of genetic gain in the commercial environment. Interactions between the nucleus and base (commercial) herds are assumed to be more important than those interactions within tiers (e. g., among base herds). The genetic selection differentials of animals born in the nucleus and evaluated for their performance under the base conditions are reduced by a factor equivalent to the genetic correlation for economic merit between the nucleus and base test environment. This leads to a lower asymptotic genetic gain per year and longer asymptotic genetic lag with regard to the genetic improvement in the base herds. The mean genetic merit in the commercial population at a given planning horizon (20 years) is also increased as the genetic correlation for economic merit between the nucleus and base environment decreases. The applies to all the breeding systems and so the genetic correlation is a critical parameter in evaluating open nucleus breeding schemes. ZUSAMMENFASSUNG: Wirkungen von Genotyp-Umweltinteraktionen in offenen Nukleuszuchtsystemen von Milchrindern Die Bewertung offener Nukleuszuchtsysteme mit Nachkommenschaftsprüfung oder adultem oder juvenilem Embryotransfer im Nukleus wird mit Berücksichtigung von Genotyp-Umweltinteraktionen erweitert. Kenntnis solcher Interaktionen sollen bei der Zuchtplanung und zur Vorausschätzung realistischer genetischer Fortschrittsraten in praxisnahen Situationen Anwendung finden. Interaktionen zwischen Nukleus und Basis (kommerziell) Herden werden als wichtiger angenommen als Interaktionen innerhalb der Schichten (z.B. zwischen Basisherden). Genetische Selektionsdifferentiale von nukleusgeborenen Tieren, die ihre Leistung unter Bedingung der Praxis erbringen, werden proportional der genetischen Korrelation für Wirtschaftswert zwischen Nukleus und Basismilieu vermindert. Dies führt zum geringeren asymptotischen genetischen Fortschritt pro Jahr und einem längeren asymptotischen, mit genetischer Verzögerung in bezug auf genetische Verbesserung der Basisherden. Der mittlere Zuchtwert der kommerziellen Population bei gegebenem Planungshorizont (20 Jahre) wird ebenfalls proportional der genetischen Korrelation kleiner. Das bezieht sich auf alle Zuchtsysteme, so daß die genetische Korrelation ein kritischer Parameter zur Bewertung offener Nukleuszuchtsysteme ist.

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Selection of Sires Originating From a Nucleus Breeding Unit for Use in a Commercial Dairy Population

Abstract: Teppxnn, G. nno Krlmn, D. S. 1989

Cited by 6 publications

References 10 publications

The contribution of a MOET nucleus scheme for the improvement of Guzerá (Bos indicus) cattle for milk traits in Brazil

The contribution of a MOET nucleus scheme for the improvement of Guzerá (Bos indicus) cattle for milk traits in Brazil

Embryo Transfer

The effects of genotype by environment interactions in dairy cattle open nucleus breeding schemes

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