Selection for litter size

Bradford, G. E.

doi:10.1016/b978-0-407-00302-6.50004-0

Cited by 56 publications

(34 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A melhoria dos índices reprodutivos geralmente resulta em maior lucratividade na exploração ovina, tendo-se mais animais para venda e possibilitando maior pressão de seleção, substituindose os menos produtivos (SELAIVE-VILLARROEL, 1984;BRADFORD, 1985;ELSEN et al, 1994).…”

Section: Introductionunclassified

Desempenho produtivo de ovelhas acasaladas no verão e no outono recebendo ou não suplementação alimentar durante o acasalamento

et al. 2002

View full text Add to dashboard Cite

Section: Introductionunclassified

Desempenho produtivo de ovelhas acasaladas no verão e no outono recebendo ou não suplementação alimentar durante o acasalamento

et al. 2002

View full text Add to dashboard Cite

“…In order to evaluate the productive ability of goats, prolificacy and birth weight are considered the most important and economic criteria (Morand-Fehr, 1981). The number of young born alive per kidding is an important factor in increasing productivity as it contributes more to the total weight weaned per dam than the growth rate of the kid (Bradford, 1985). It is evident that the short generation interval, non seasonality and multiple births of goat make it possible to increase production more rapidly than other ruminants in the tropics.…”

Section: Introductionmentioning

confidence: 99%

Selection of Black Bengal Buck Based on Some Reproductive Performance of Their Progeny at Semi-Intensive Rearing System

Husain

Khandoker

et al. 2013

JAS

View full text Add to dashboard Cite

The objective of this study was to select Black Bengal Buck Based on some reproductive performance of their progeny. The least-squares means for overall reproductive performances of age of first kidding (AFK), weight at first kidding (WFK), gestation length (GL), kidding interval (KI), post-partum heat (PPT), litter size at birth (LS) and litter weight at birth were 465.6 days, 13.22 kg, 145.34 days, 302.5 days, 123.84 days, 1.61 and 1.66 kg, respectively. The effect of flock and generation were significant (p<0.05) for AFK, WFK, KI, PPT, LS and LWB. The effect of parity of doe was significant (p<0.01) for LSB and LWB. The effect of season was significant (p<0.05) for KI, PPT and LWB. The heritability value for these traits was ranges from 0.17 to 0.24 and predicted breeding value from -0.003 to 0.445. According to the genetic worth of the buck the highest breeding value of reproductive traits were found in the progeny of Buck No. 32, followed by Buck No. 52, 54, 81 and 87. This progeny tested bucks may be used for the improvement of the reproductive potentials of Black Bengal goat through Artificial Insemination (A.I). The lowest breeding value of reproductive traits was found from the progeny of Buck No. 3 followed by Buck No. 11. The low estimates of heritability obtained for reproductive traits indicated that selection based on the doe's own performance may result in slow genetic improvement therefore; the progeny testing program will be beneficial to the farmers and fulfill their need by supplying superior sires of high genetic merit.

show abstract

“…Litter size, for example, can only be measured in mature females and has a mean realized heritability of about 007 in sheep (Bradford, 1985). Selection pressure for litter size is necessarily limited by the need to select sufficient females to maintain the flock and a long generation interval is dictated by the need to measure the trait in mature females.…”

Section: Introductionmentioning

confidence: 99%

Study of LH response to GnRH in the young male as a criterion of genetic merit for female reproduction in sheep

Haley¹,

Lee²,

Fordyce³

et al. 1989

Reproduction

View full text Add to dashboard Cite

Summary. A high and a low response line in sheep were selected on the basis of the mean concentration of LH in 10-week-old Finn\p=n-\Dorsetram lambs after an i.v. injection of 5 \g=m\g GnRH. After 8 male generations the mean LH response of the high line was more than 5-fold that of the low line and the heritability of the selected trait was estimated at 0\m=.\44 \m=+-\0\m=.\015. Highly significant line differences in mean LH response to GnRH were also found in males at 20 weeks of age and females at 10 and 20 weeks of age and the genetic correlations between the four LH response traits appear to be close to unity. Large line differences in the mean FSH response to GnRH were also found in both males and females at 10 and 20 weeks of age. Selection had little effect on the physical characteristics of lambs. High-response line ewes entering their first breeding season at about 7 months of age showed oestrus earlier in the season and had higher ovulation rates and numbers of lambs born per ewe lambing than did low-response line ewes. In the second breeding season, at about 19 months of age, the only line difference was a higher ovulation rate early in the breeding season in high-line ewes. It is suggested that these changes may be mediated by a more rapid response in high-line ewes to increased GnRH stimulation at puberty or at the beginning of the breeding season.

show abstract

Selection for litter size

Cited by 56 publications

References 35 publications

Desempenho produtivo de ovelhas acasaladas no verão e no outono recebendo ou não suplementação alimentar durante o acasalamento

Desempenho produtivo de ovelhas acasaladas no verão e no outono recebendo ou não suplementação alimentar durante o acasalamento

Selection of Black Bengal Buck Based on Some Reproductive Performance of Their Progeny at Semi-Intensive Rearing System

Study of LH response to GnRH in the young male as a criterion of genetic merit for female reproduction in sheep

Contact Info

Product

Resources

About