Direct Response in Yield and Correlated Response in Components Accompanying Selection for Milk Yield in Jerseys

AbstractResponses to divergent selection for lean growth rate with ad-libitum feeding (LGA), for lean food conversion (LFC) and for daily food intake (DFI) in Landrace pigs were studied. Selection was practised for four generations with a generation interval ofl year. A total of 2642 pigs were performance tested in the high, low and control lines, with an average of 37 boars and 39 gilts performance tested per selection line in each generation. The average within-line inbreeding coefficient at generation four was equal to 0·04. There was one control line for the DFI and LFC selection groups and another control line for the LGA selection group. Animals were performance tested in individual pens with mean starting and finishing weights of 30 kg and 85 kg respectively with ad-libitum feeding. The selection criteria had phenotypic s.d. of 32, 29 and 274 units, for LGA, LFC and DFI, respectively, and results are presented in phenotypic s.d.Cumulative selection differentials (CSD) were 5·1, 4·5 and 5·5 phenotypic s.d. for LGA, LFC and DFI, respectively. Direct responses to selection were 1·4,1·1 and 0·9 (s.e. 0·20) for LGA, LFC and DFI. In each of the three selection groups, the CSD and direct responses to selection were symmetric about the control lines. The correlated response in LFC (1·1, s.e. 0·19) with selection on LGA was equal to the direct response in LFC. In contrast, the direct response in LGA was greater than the correlated response (0·7, s.e. 0·18) with selection on LFC. There was a negative correlated response in DFI (-0·6, s.e. 0·18) with selection on LFC, but the response with selection on LGA was not significant (0·2, s.e. 0·16).Heritabilities for LGA, LFC and DFI ivere 0·25, 0·25 and 0·18 (s.e. 0·03), when estimated by residual maximum likelihood, with common environmental effects of 0·12 (s.e. 0·02). Genetic correlations for LFC with LGA and DFI were respectively positive (0·87, s.e. 0·02) and negative (-0·36, s.e. 0·09), while the genetic correlation between DFI and LGA was not statistically different from zero, 0·13 (s.e. 0·10). Selection on components of efficient lean growth has identified LGA as an effective selection objective for improving both LGA and LFC, without a reduction in DFI.

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Selection for growth on normal and reduced protein diets in mice: I. Direct and correlated responses for growth

Genetics Research ◽

10.1017/s0016672300023272 ◽

1987 ◽

Vol 50 (1) ◽

pp. 7-15 ◽

Cited By ~ 13

Author(s):

B. Vivi Hunnicke Nielsen ◽

Søren Andersen

Keyword(s):

Protein Level ◽

Protein Diet ◽

Correlated Response ◽

Family Selection ◽

Direct Response ◽

Protein Levels ◽

Selection Environment ◽

Normal Protein Diet ◽

Selection For ◽

Protein Diets

SummaryMice were selected for growth from 3 to 9 weeks of age on a normal protein diet (N) containing 19·3% protein and a reduced protein diet (R) containing 5·1% protein. On each diet there were 3 high (H), 3 low (L) and 3 unselected control (C) lines. After 6 generations of selection, half of the mice in each line were tested on each diet. Responses were obtained when selecting for both increased and decreased growth on both diets. The realized heritabilities from within-family selection were 33 and 26% for the divergences on the normal and reduced protein diets, respectively. Consistent genotype-environment interactions were found when all lines were tested on both diets in generation 7. Performance on each protein level was best improved by selection on that protein level. Further, the correlated response was significantly less than the direct response when selecting on both diets. The estimates of the genetic correlation between growth on the two protein levels were low, rN = 0·16 from selection on the normal protein diet and rR = 0·51 from selection on the reduced protein diet. Selection resulted in a change in environmental sensitivity in the lines, dependent on the diet and direction of selection. The average of the divergences on the two diets was not dependent on the selection environment.

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Selection for ovulation rate in rabbits: Genetic parameters, direct response, and correlated response on litter size1

Journal of Animal Science ◽

10.2527/jas.2011-3906 ◽

2011 ◽

Vol 89 (10) ◽

pp. 2981-2987 ◽

Cited By ~ 13

Author(s):

P. Laborda ◽

M. L. Mocé ◽

M. A. Santacreu ◽

A. Blasco

Keyword(s):

Genetic Parameters ◽

Ovulation Rate ◽

Correlated Response ◽

Direct Response ◽

Selection For

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Selection for components of efficient lean growth rate in pigs 1. Selection pressure applied and direct responses in a Large White herd

Animal Science ◽

10.1017/s0003356100007741 ◽

1994 ◽

Vol 59 (2) ◽

pp. 251-262 ◽

Cited By ~ 43

Author(s):

N. D. Cameron

Keyword(s):

Growth Rate ◽

Divergent Selection ◽

Correlated Response ◽

Food Conversion ◽

Correlated Responses ◽

Direct Response ◽

Large White ◽

Selection For ◽

The Difference ◽

And Control

AbstractResponses to four generations of divergent selection for lean groivth rate with ad-libitum feeding (LGA), for lean food conversion (LFC) and for daily food intake (DFI) in Large White pigs were studied. The LGA (LFC) selection criterion was designed to obtain equal correlated responses in growth rate (food conversion ratio) and carcass lean content, measured in phenotypic s.d. The selection criteria had phenotypic s.d. of 27, 29 and 253 units, respectively, and results are presented in s.d. units. There was a total of 3537 pigs, with an average of 40 boars and 40 gilts performance tested in each of the high, low and control lines per generation and the lines consisted of 10 sires and 20 dams. The generation interval was equal to 13·5 months. Animals were performance tested in individual pens with mean starting and finishing weights of 30 kg and 85 kg respectively.Cumulative selection differentials in the three selection groups were 5·8, 3·6 and 3·3 phenotypic s.d. for LGA, LFC and DFI respectively. Direct responses to divergent selection were 1·7, 1·3 and 1·2 (s.e. 0·17) for LGA, LFC and DFI. The correlated response in LFC (1·6 (s.e. 0·18)) with selection on LGA was greater than the direct response in LFC. Conversely, the direct response in LGA was greater than the correlated response (1·1 (s.e. 0·18)) with selection on LFC. The response in LFC (–1·1 (s.e. 0·17)) with selection on DFI was similar in size but opposite in sign to the direct response in LFC. Responses were asymmetric about the control, as the high LGA and LFC responses were proportionately smaller (0·74 and 0·58) than low line responses. In contrast, the difference between the high DFI and control was four times greater than the difference between low line and control.Heritabilities of LGA, LFC and DFI were 0·38, 0·35 and 0·29 (s.e. 0·03), when estimated by residual maximum likelihood, with common environmental effects of 0·09 (s.e. 0·02). Genetic correlations for LGA with LFC and DFI were positive, 0·76 (s.e. 0·03) and 0·23 (s.e. 0·07), but the genetic correlation between DFI and LFC was negative, –0·45 (s.e. 0·06). The experiment demonstrated that substantial responses to selection can be achieved in LGA, LFC and DFI. Selection on LGA resulted in larger direct and correlated responses than selection on LFC.

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MILK YIELD IN LINES OF MICE SELECTED FOR GROWTH OR MATERNAL ABILITY

Canadian Journal of Genetics and Cytology ◽

10.1139/g75-034 ◽

1975 ◽

Vol 17 (2) ◽

pp. 263-268 ◽

Cited By ~ 3

Author(s):

J. M. White

Keyword(s):

Milk Yield ◽

Body Weight Gain ◽

Correlated Response ◽

Response To Selection ◽

Litter Weight ◽

Average Production ◽

Before And After ◽

Selection For ◽

And Control ◽

Gain Line

Two experiments were conducted to measure milk yield as a correlated response to selection for increased 12-day litter weight (maternal lines) for 13 generations and increased and decreased body weight gain from 21 to 42 days of age (postweaning gain lines) for 12 to 14 generations. Milk yield was measured from day 6 to day 21 of lactation by separating litters from their dams for 6 h, then weighing litters before and after a 1.5 h suckling period. Average total milk production was 30.3 ± 0.9 g and 28.6 ± 1.1 g in maternal and control lines, respectively. This difference was not significant (P > 0.05). Differences among gain lines were significant (P < 0.01) in the second experiment with average production of 44.1 ± 1.4 g for increased gain lines, 22.5 ± 0.9 g for the decreased gain line and 31.2 ± 1.0 g for the control. These results indicated that response to selection for increased 12-day litter weight was not associated with increases in milk yield, but sizable changes in milk yield accompanied bi-directional selection for early postweaning gain.

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Relationship between milk composition and yield of milk, fat and protein in Red Danish cattle

Animal Science ◽

10.1017/s0003356100026465 ◽

1968 ◽

Vol 10 (4) ◽

pp. 445-450 ◽

Cited By ~ 6

Author(s):

K. Christensen

Keyword(s):

Milk Yield ◽

Milk Fat ◽

Genetic Correlations ◽

Protein Yield ◽

Direct Selection ◽

Correlated Response ◽

Logarithmic Scale ◽

Progeny Testing ◽

Fat Yield ◽

Selection For

The relationships among five traits in dairy cattle (milk yield, fat yield, protein, fat % and protein %) were examined on the original and on a logarithmic scale. The data comprised the records on 5333 Red Danish cows tested at the Danish Progeny Testing Stations during the years 1960–66. None of the heritabilities or the correlations among the variates were altered appreciably by transformation. For the five traits heritability estimates were 0·56, 0·80, 0·65, 0·64 and 0·56, respectively. Phenotypic and genetic correlations among milk yield, fat yield and protein yield were all very high, about 0·95. The correlations between fat % and protein % were about 0·6. The coefficient of variation of a variate proved to be a good approximation of the standard deviation of the transformed variate even for milk, fat and protein yield with coefficients of variation of 17–18%. It was concluded that little is likely to be gained by using index selection for fat yield and protein yield. However, about 90% of the response obtainable by direct selection for fat or protein yield could be obtained merely by selection for milk yield. A large correlated response for protein yield could be obtained by selecting for fat yield.

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