Selection for Increased Rate or Efficiency of Lean Growth in Rats: Correlated Responses in Reproductive Performance

1981 ◽  
Vol 53 (6) ◽  
pp. 1458-1464 ◽  
Author(s):  
R. D. Allrich ◽  
C. T. Wang ◽  
G. E. Dickerson ◽  
Dwane R. Zimmerman
1990 ◽  
Vol 51 (1) ◽  
pp. 23-34 ◽  
Author(s):  
R. A. Mrode ◽  
C. Smith ◽  
R. Thompson

ABSTRACTSelection of bulls for rate and efficiency of lean gain was studied in a herd of Hereford cattle. There were two selection lines, one selected for lean growth rate (LGR) from birth to 400 days and the other for lean food conversion ratio (LFCR) from 200 to 400 days of age, for a period of 8 years. A control line bred by frozen semen from foundation bulls was also maintained. Generation interval was about 2·4 years and average male selection differentials, per generation were 1·2 and — 1·1 phenotypic standard deviation units for LGR and LFCR respectively.Genetic parameters and responses to selection were estimated from the deviation of the selected lines from a control line and by restricted maximum likelihood (REML) techniques on the same material. Realized heritabilities were 0·40 (s.e. 0·12) for LGR and 0·40 (s.e. 0·13) for LFCR using the control line. Corresponding estimates from REML were 0·42 (s.e. 0·10) and 0·37 (s.e. 0·14). The estimate of the genetic correlation between LGR and LFCR was about — 0·69 (s.e. 0·12) using REML.The estimates of direct annual genetic change using deviations from the control were 3·6 (s.e. 1·3) g/day for LGR and — 0·14 (s.e. 0·07) kg food per kg lean gain for LFCR. Corrsponding estimates from REML were similar but more precisely estimated. The correlated responses for LFCR in the LGR line was higher than the direct response for LFCR.


2001 ◽  
Vol 81 (2) ◽  
pp. 205-214 ◽  
Author(s):  
P. Chen ◽  
T. J. Baas ◽  
J. C. M. Dekkers ◽  
L. L. Christian

Selection for lean growth rate (LGR) was conducted for four generations in a synthetic line of Yorkshire-Meishan pigs to study the effectiveness of selection for LGR and correlated responses in litter traits. Lean growth rate was estimated from ultrasound measurements of 10th-rib backfat thickness and longissimus muscle area. In the selection line, 7 boars and 20 gilts with the highest LGR were selected to produce the next generation. The generation interval was 13 mo and the average selection differential per generation was 1.1 phenotypic standard deviation units. A contemporaneous control line was maintained by randomly selecting 5 boars and 15 gilts. Data from a total of 1057 pigs sired by 58 boars and out of 133 sows were available from the two lines. Selection responses were estimated from deviations of the selection line from the control line using least squares (LS) and by multiple trait derivative-free restricted maximum likelihood analysis using an animal model (AM). The estimate of response to selection per generation using LS was 9.4 ± 0.95 g d–1 for LGR. The corresponding estimate from the AM was 9.8 ± 0.51 g d–1. Correlated responses in litter traits were regressed on generation. For the LS method, regression coefficients were negative but not significant (P > 0.05) for total number born, number born alive, and number at 21 d and at 42 d. Significant, positive correlated responses occurred in 42-d litter weight and 21-d piglet weight (P < 0.05). For the AM method, the regression coefficients were also negative, but were not significant (P > 0.05) for numberalive at birth, at 21 d, and at 42 d. A significant positive correlated response occurred only for 42-d litter weight (P < 0.05). Although results are based on a population of limited size, it can be concluded that selection for LGR in a synthetic line is effective and should have little effect on litter traits. Key words: Pigs, selection, lean growth rate, correlated response


Author(s):  
E.A. Bruce ◽  
N. D. Cameron ◽  
M.K. Curran

This study determined the correlated responses in carcass composition after four generations of divergent selection for components of efficient lean growth rate in Large White (LW) and Landrace (LR) pigs.


Author(s):  
N.D. Cameron

An experiment was started in 1984 at Edinburgh and Wye to study responses to divergent selection for lean growth rate (LGA), lean food conversion ratio (LFC) and daily food intake (DFI). This paper measured the selection pressure applied, the responses in the selection criteria and estimated the genetic and phenotypic relationships between the selection criteria with ad-libitum feeding of Large White pigs after four generations of selection.Selection objectives and criteria. The LGA (LFC) selection objective was to obtain equal correlated responses in growth rate (food conversion ratio) and carcass lean content, measured in phenotypic s.d. The LGA, LFC and DFI selection criteria had phenotypic s.d. of 27, 29 and 250 units and results are presented in s.d. units.


1995 ◽  
Vol 60 (2) ◽  
pp. 281-290 ◽  
Author(s):  
J. C. Kerr ◽  
N. D. Cameron

AbstractCorrelated responses in reproductive performance to five generations of divergent selection for daily food intake (DFI), lean food conversion (LFC), lean growth rate on ad–libitum feeding (LGA), and lean growth rate on scale feeding (LGS) were studied. Litter traits were measured on 1220 Large White gilts. Mean litter weights at birth and weaning were 12·9 kg and 63·5 kg, with average litter sizes of 10·3 and 7·9. Responses to selection in the high and low lines for litter size in the DFI and LFC selection groups were 1·9 and –1·5 (s.e.d. VI) at birth and 0·9 and –1·8 (s.e.d. 1·2) at weaning. Responses in litter birth weights were respectively positive and negative for DFI and LFC (3·0 and –2·8 (s.e.d. 1·4) kg) and the response in LGS (3 kg) was greater than in LGA (–0·1 kg). Selection line differences in litter weaning weight followed a similar pattern to birth weight for DFI and LFC (17·5 and –17·3 (s.e.d. 10·1) kg). Responses in litter weights were a result of selection line differences in both litter sizes and piglet weights. The relationships between litter size, litter weights and piglet weights at birth and weaning were essentially linear. An extra piglet at birth and weaning corresponded to an increase of 1·0 (s.e. 0·02) kg and 6·9 (s.e. 0·1) kg in litter weights. Piglet birth and weaning weights were decreased by 0·03 (s.e. 0·003) kg and 0·19 (s.e. 0·02) kg. A uterine constraint on piglet growth was implied, but there was no evidence for a limit to uterine capacity. Heritabilities for litter size, weight and piglet weight at birth of 0·06, 0·11 (s.e. 0·04) and 0·16 (s.e. 0·02) respectively were similar to those at weaning. Common environmental effects on piglet weights at birth and weaning were substantially higher than the heritabilities (0·38 and 0·45, s.e. 0·01). The study indicated that selection for lean growth on either an ad–libitum or restricted feeding regime did not significantly affect reproductive performance, but the high lean food conversion ratio and low daily food intake selection lines had impaired reproductive performance.


Crop Science ◽  
2002 ◽  
Vol 42 (3) ◽  
pp. 730 ◽  
Author(s):  
C. T. Cervantes-Martinez ◽  
K. J. Frey ◽  
P. J. White ◽  
D. M. Wesenberg ◽  
J. B. Holland

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 18-18
Author(s):  
Leticia P Sanglard ◽  
Felipe Hickmann ◽  
Yijian Huang ◽  
Kent A Gray ◽  
Daniel Linhares ◽  
...  

Abstract Immunoglobulin G antibody response, measured as sample-to-positive (S/P) ratio, to Porcine Reproductive and Respiratory Syndrome virus (PRRSV) has been proposed as an indicator trait for improved reproductive performance in PRRSV-infected purebred sows and PRRSV-vaccinated crossbred gilts. In this study, we investigated the genetic correlations (rg) of S/P ratio following a PRRSV outbreak and PRRSV-vaccination with performance in non-exposed and PRRSV-exposed sows. PRRSV outbreak phase was defined based on previously described methodologies after the detection of typical clinical signs of PRRSV infection. 541 Landrace sows had S/P ratio measured at ~54 days after the beginning of the PRRSV outbreak (S/Poutbreak), and 906 Landrace x Large White naïve F1 gilts had S/P ratio measured at ~50 days after vaccination with a commercial modified live PRRSV vaccine (S/PVx). 711 and 428 Landrace sows had reproductive performance recorded before and during the PRRSV outbreak, respectively. 811 vaccinated F1 animals had farrowing performance for up to 3 parities. All animals were genotyped for ~28K SNPs. The estimate of rg of S/Poutbreakwith S/PVx was high (rg±SE = 0.72±0.18). Estimates of rg of S/Poutbreak with reproductive performance in F1 sows were low to moderate, ranging from 0.05±0.23 (number stillborn) to 0.30±0.20 (total number born). Estimates of rg of S/PVxwith reproductive performance in non-infected purebred sows were moderate and favorable with number born alive (0.50±0.23), but low (0 to -0.11±0.23) with litter mortality traits. Estimates of rg of S/PVx were moderate and negative (-0.47±0.18) with the number of mummies in PRRSV-infected purebred sows and low with other traits (-0.29±0.18 for total number born to 0.05±0.18 for number stillborn). These results indicate that selection for antibody response following a PRRSV outbreak collected in purebred sows and to PRRSV vaccination collected in commercial crossbred gilts may increase litter size of non-infected and PRRSV-exposed purebred and commercial crossbred sows.


Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 519
Author(s):  
Shajahan Ferosekhan ◽  
Serhat Turkmen ◽  
Cathaysa Pérez-García ◽  
Hanlin Xu ◽  
Ana Gómez ◽  
...  

Genetic selection in gilthead seabream (GSB), Sparus aurata, has been undertaken to improve the growth, feed efficiency, fillet quality, skeletal deformities and disease resistance, but no study is available to delineate the effect of genetic selection for growth trait on GSB reproductive performance under mass spawning condition. In this study, high growth (HG) or low growth (LG) GSB broodstock were selected to evaluate the sex steroid hormones, sperm, egg quality and reproductive performance under different feeding regime of commercial diet or experimental broodstock diet containing either fish oil (FO) or vegetable oil (VO) based diet. Under commercial diet feeding phase, broodstock selected for either high growth or low growth did not show any significant changes in the egg production per kg female whereas egg viability percentage was positively (p = 0.014) improved by the high growth trait broodstock group. The experimental diet feeding results revealed that both growth trait and dietary fatty acid composition influenced the reproductive performance of GSB broodstock. In the experimental diet feeding phase, we observed high growth trait GSB males produced a higher number of sperm cells (p < 0.001) and also showed a higher sperm motility (p = 0.048) percentage. The viable egg and larval production per spawn per kg female were significantly improved by the broodstock selected for high growth trait and fed with fish oil-based diet. This present study results signifies that gilthead seabream broodstock selected on growth trait could have positive role in improvement of sperm and egg quality to produce viable progeny.


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