Optimized testing schemes using nucleus progeny, adult MOET siblings, or juvenile MOET pedigrees in dairy cattle closed populations

Bondoc, Orville L.; Smith, C.

doi:10.1111/j.1439-0388.1993.tb00714.x

Cited by 9 publications

(11 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The two‐tier structure that uses optimal nucleus progeny testing, adult MOET sib testing, or juvenile MOET pedigree testing in hierarchical mating systems in the nucleus is proposed for smallholder dairy cattle genetic improvement (B ondoc and S mith 1993). The testing schemes were initially optimized for different numbers of sires used and first lactation females recorded per year.…”

Section: Methodsmentioning

confidence: 99%

“…A local testing and selection program in nucleus breeding units is proposed to improve genetically the local dairy cattle populations (indigenous, adapted exotic, composite or stabilized crossbreds). Special emphasis is given on smallholder production systems in developing countries, although a full range of population sizes and low, medium, and high levels of reproductive rates (as in B ondoc and S mith 1993) are considered for completeness and comparisons of predicted selection response rates with developed countries. The low and medium levels represented reproductive rates from specialized milk production systems using indigenous ( Bos indicus ) and adapted exotic ( Bos taurus ) dairy cattle breeds respectively, in developing countries.…”

Section: Introductionmentioning

confidence: 99%

“…A deterministic model is used to predict steady state selection response, genetic (improvement) lag, annual inbreeding rates, and mean breeding values in the nucleus, in the base, and in the total population for various open nucleus breeding schemes. The effects of different reproductive and MOET rates (from B ondoc and S mith 1993), different heritability (and repeatability) in the nucleus and in the base, and no recording of females in the base population are also investigated.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Deterministic genetic analysis of open nucleus breeding schemes for dairy cattle in developing countries

Bondoc

Smith

1993

J Animal Breeding Genetics

Self Cite

View full text Add to dashboard Cite

A deterministic model is used to analyze the genetic properties of a two tier dairy cattle open nucleus breeding system proposed in developing countries. Theoretical selection response rates are adjusted to account for the effects of population size and structure, selection disequilibrium, sampling losses, inbreeding, and planning horizon. Optimized nucleus progeny testing, adult or juvenile multiple ovulation and embryo transfer in sib or pedigree testing schemes are used in the nucleus. All sires come from the nucleus. Females in the base herds may be recorded and selected as bull dams or donor cows in the nucleus. The predicted genetic means in the base after a given planning horizon (20 years) for a range of situations studied, is generally highest for adult sib testing, but is higher for nucleus progeny testing than for juvenile pedigree testing schemes. The genetic means are higher with more females in the nucleus and with higher reproductive and embryo transfer success rates. The genetic level of the base is higher with higher fractions of nucleus dams born in the base, but is little affected by the proportion of the total population included in the nucleus. The genetic responses are also reduced when heritability in the base is lower than in the nucleus. Policies on the formation and running of an efficient open nucleus breeding system are discussed. Key words: nucleus breeding schemes, nucleus progeny testing, multiple ovulation and embryo transfer, genetic improvement. ZUSAMMENFASSUNG: Deterministische genetische Analyse eines offenen Nukleussystems für Milchrinder in Entwicklungsländern Ein deterministisches Modell wurde zur Analyse der genetischen Eigenheiten eines "Zwei-Stufen offenen Nukleuszuchtsystem" für Milchrinder für Entwicklungsländer verwendet. Theoretische Selektionserfolgsraten unter Berücksichtigung der Wirkungen von Populationsgröße und Struktur, Selektionsungleichgewicht, Zufallsschwankungen, Inzucht und Planungszeitraum für optimierte Nukleusnachkommenschaftsprüfung, adulte oder juvenile multiple Ovulation und Embryotransfer mit Geschwister- oder Pedigreeprüfungsplänen werden berechnet. Alle Vatertiere kommen von Nukleus, Muttertiere in den Basisherden z. T. leistungsgeprüft werden als Bullenmütter oder Spenderkühe im Nukleus verwendet. Das für die Basis geschätzte genetische Leistungsniveau eines gegebenen Planungshorizonts (20 Jahre) wird für eine Reihe von Situationen untersucht und ist im allgemeinen am höchsten für adulte Geschwisterprüfungssysteme, aber höher für Nukleusnachkommenschaftsprüfung als für juvenile Pedigreeprüfungspläne. Genetische Fortschritte sind höher, wenn mehr weibliche Tiere im Nukleus und höhere Reproduktions- und Transfererfolgsraten existieren. Das genetische Niveau der Basis ist höher, wenn ein höherer Anteil von Nukleusmuttertieren aus der Basis stammt, aber es wird wenig vom Nukleusanteil der gesamten Population tangiert. Der genetische Fortschritt wird reduziert, wenn Rentabilität in den Basisherden niedriger als im Nukleus ist. Die Strategien zur Bildu...

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Deterministic genetic analysis of open nucleus breeding schemes for dairy cattle in developing countries

Bondoc

Smith

1993

J Animal Breeding Genetics

Self Cite

View full text Add to dashboard Cite

show abstract

“…The genetic theory in dairy cattle open nucleus breeding schemes (see B ondoc and S mith 1993b) is extended to include genotype by environment interactions. Optimized nucleus progeny testing, adult MOET sib testing, or juvenile MOET pedigree testing (from B ondoc and S mith 1993a) are used in the nucleus, while females in the base are field recorded. Base‐born (tested) females are allowed to be used in the nucleus.…”

Section: Methodsmentioning

confidence: 99%

“…The high reproductive rates represent efficient reproduction schemes in developed countries. (See B ondoc and S mith 1993a). The rate of inbreeding is expected to be low and less important in open nucleus breeding systems (B ondoc and S mith 1993b) and is not discussed here.…”

Section: Methodsmentioning

confidence: 99%

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

Bondoc

Smith

1993

J Animal Breeding Genetics

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Controlling inbreeding in dairy MOET nucleus schemes

1995

View full text Add to dashboard Cite

A nucleus dairy population using multiple ovulation and embryo transfer (MOET) was stochastically modelled with overlapping generations. The aim was to investigate the feasibility of controlling inbreeding in MOET breeding schemes using more realistic parameters for embryo recovery and best linear unbiased prediction (BLUP) for genetic evaluation. Four different cases (involving the culling of donors, more donors and the use of organized progeny testing of nucleus bulls) were studied in combination with nested and factorial designs. Further studies involved modifications of the selection index, including subtracting parental breeding values, inflating the genetic variance in the BLUP evaluation and penalizing inbred animals; these options were examined both with and without organized progeny testing. The effects of applying these schemes on both genetic response and rate of inbreeding were investigated. The results stressed the importance of incorporating progeny testing into MOET schemes for value of reducing inbreeding whilst maintaining genetic progress. There was no significant difference between nested and factorial designs. In the absence of progeny testing the inflation of genetic variance was more effective than subtracting parental breeding values at controlling inbreeding; however incorporating progeny testing made the latter strategy more potent and the superiority of inflating the genetic variance was in this case much smaller and non-significant.

show abstract

Optimized testing schemes using nucleus progeny, adult MOET siblings, or juvenile MOET pedigrees in dairy cattle closed populations

Cited by 9 publications

References 13 publications

Deterministic genetic analysis of open nucleus breeding schemes for dairy cattle in developing countries

Deterministic genetic analysis of open nucleus breeding schemes for dairy cattle in developing countries

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

Controlling inbreeding in dairy MOET nucleus schemes

Contact Info

Product

Resources

About