Selection for lean growth in pigs with a restricted feeding regime

1994 ◽  
Vol 1994 ◽  
pp. 12-12
Author(s):  
M.K. Curran ◽  
N.D. Cameron ◽  
J.C. Kerr
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Restricted Feeding ◽  
Correlated Responses ◽  
Large White ◽  
Daily Food Intake ◽  
Feeding Regime ◽  
Lean Growth ◽  
Daily Food ◽  
Ad Libitum

Divergent selection lines for lean growth on a restricted feeding regime, in Large White and Landrace pigs, were established to complement the lean growth selection lines on ad-libitum feeding. This study estimated the direct and correlated responses after four generations of selection and the corresponding genetic and phenotypic parameters.The selection objective for lean growth on restricted or scale (LGS) feeding was to obtain equal correlated responses in growth rate and carcass lean content, measured in phenotypic s.d. The selection criterion included measurements of growth rate and ultrasonic backfat depth.Large White (LW) and Landrace (LR) boars and gilts were purchased from eight British nucleus herds and boars from national artificial insemination centres in 1982. Homozygous or heterozygous halothane positive pigs were not included in the experiment. The base populations consisted of 31 LW and 19 LR sires and 57 LW and 67 LR dams. Within each population, there were high and low selection lines with a control line, each consisting of 10 boars and 20 gilts, with a generation interval of 13.5 and 12 months for LW and LR pigs. Animals were performance tested in individual pens from 30±3 kg for a period of 84 days and fed a high energy (13.8 MJ DE/kg DM) and high protein (210 g/kg DM crude protein) pelleted ration. Daily food intake was equal to 0.75 g/g of the daily food intake for ad-libitum fed pigs and the total food intake was 134 kg for LW pigs and 150 kg for LR pigs. On average, 3 boars and 3 gilts were tested per litter. The total number of pigs tested per line and average inbreeding coefficients at generation four, by population are given below.

Responses in carcass composition to divergent selection for components of efficient lean growth rate in pigs

1995 ◽  
Vol 61 (2) ◽  
pp. 347-359 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Fat Content ◽  
Restricted Feeding ◽  
Food Conversion ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food ◽  
Ad Libitum ◽  
Selection For

AbstractCarcass composition was measured after six generations of divergent selection for lean growth rate on ad-libitum and restricted feeding, lean food conversion and daily food intake in populations of Large White (LW) and Landrace (LR) pigs. There were 161 half-carcass dissections in LW pigs and for LR pigs, a double sampling procedure combined information from 53 half-carcass and 53 hand joint dissections. The performance test started at 30 kg and finished at 85 kg with ad-libitum feeding and after 84 days with restricted feeding, and pigs were slaughtered at the end of the test.In the LR population, selection for lean growth on restricted feeding increased carcass lean content (605 v. 557 (s.e.d. 19) g/kg), but there were no significant responses in carcass lean content with the selection strategies on adlibitum feeding. Selection for lean food conversion and high lean growth on restricted feeding reduced carcass fat content (201 v. 241 (s.e.d. 14) and 150 v. 218 (s.e.d. 18) g/kg), but selection for high lean growth rate with adlibitum increased carcass fat content (212 v. 185 (s.e.d. 11) g/kg). Responses in carcass composition were not significant with selection on daily food intake.In the LW population, selection for high lean food conversion or low daily food intake increased carcass lean content (539 v. 494 and 543 v. 477 (s.e.d. 11) g/kg) to a greater extent than selection on lean growth rate (509 v. 475 g/kg). Responses in carcass fat content were equal and opposite to those in carcass lean content. Selection on lean growth rate with ad-libitum feeding increased lean tissue growth rate (LTGR) (491 v. 422 (s.e.d. 23) g/day), but there was no change in fat tissue growth rate (FTGR) (206 v. 217 (s.e.d. 15) g/day). In contrast, FTGR was reduced with selection on lean food conversion (169 v. 225 g/day), but LTGR was not significantly increased (520 v. 482 g/day). Selection for lean growth rate with restricted feeding combined the desirable strategies of lean growth rate on adlibitum feeding and lean food conversion, as LTGR was increased (416 v. 359 (s.e.d. 12) g/day) and FTGR decreased (126 v. 156 (s.e.d. 7) g/day). The preferred selection strategy may be lean growth rate on restricted feeding, which simultaneously emphasizes rate and efficiency of lean growth.For ad-libitum fed LW pigs, coheritabilities for growth rate, daily food intake and backfat depth with carcass lean content were negative (-0·12, -0·22 and -0·50 (s.e. 0·05), but positive with carcass subcutaneous fat content (0·22, 0·24 and 0·50), when estimated from six generations of performance test data and carcass dissection data in generations 2, 4 and 6.

Rate and site of fat deposition in pigs selected for components of efficient lean growth rate

1995 ◽  
Vol 1995 ◽  
pp. 12-12
Author(s):  
N.D. Cameron
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Divergent Selection ◽  
Fat Deposition ◽  
Food Conversion ◽  
Large White ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food ◽  
Ad Libitum

Rates and sites of fat deposition were measured in a population of Large White pigs, after six generations of divergent selection on lean growth rate with ad-libitum (LGA) and restricted (LGS) feeding, lean food conversion (LFC) and daily food intake (DFI).

Genetic and phenotypic relationships between performance test and reproduction traits in Large White pigs

1996 ◽  
Vol 62 (3) ◽  
pp. 531-540 ◽  
Author(s):  
J. C. Kerr ◽  
N. D. Cameron
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Genetic Correlations ◽  
Restricted Feeding ◽  
Daily Food Intake ◽  
Daily Food ◽  
Reproduction Traits ◽  
Ad Libitum ◽  
Ad Libitum Feeding

AbstractGenetic and phenotypic relationships between performance test and reproduction traits were estimated, after five generations of divergent selection for components of efficient lean growth, in a population of Large Wltite pigs. On ad-libitum feeding, a total of 4334 pigs were performance tested, of which 884 selected gilts had measurements of reproduction traits. On a restricted feeding regime, 1558 pigs were tested, which included 336 selected gilts with reproduction records. For pigs given food ad libitum, genetic correlations between litter weights at birth and weaning with daily food intake (0·48 and 0·42, s.e. 0·16) and with growth rate on test (0·65 and 0·52) were positive, but correlations with backfat depths were not significantly different from zero. For pigs given food at a restricted level, litter birth weight was positively genetically correlated with growth rate (0·50, s.e. 0·18) and negatively correlated with backfat depths (-0·48, s.e. 0·16). Phenotypic and environmental correlations between performance test and reproduction traits were all less than 0·10 in magnitude, for pigs tested on either feeding regime. The variation in backfat depth enabled detection of a non-linear relationship between predicted breeding values for litter weight at birth with predicted breeding values for average backfat depth of farrowing gilts performance tested on ad-libitum feeding, but not for gilts tested on restricted feeding. The positive genetic correlations between growth rate and daily food intake with litter traits suggested that selection strategies which change growth and daily food intake may result in relatively greater genetic changes in piglet growth rate than in litter size.

Associations of acute phase protein levels with growth performance and with selection for growth performance in Large White pigs

2005 ◽  
Vol 81 (2) ◽  
pp. 213-220 ◽  
Author(s):  
M. Clapperton ◽  
S. C. Bishop ◽  
N. D. Cameron ◽  
E. J. Glass
Keyword(s):  
Weight Gain ◽  
Food Intake ◽  
Daily Weight Gain ◽  
Restricted Feeding ◽  
Large White ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food ◽  
Performance Traits ◽  
Selection For

AbstractAbstract Acute phase proteins (APP) are released into the circulation in mammals upon infection and may be used to diagnose the health status of managed populations of animals such as pigs. The current study determines APP levels in a population of apparently healthy Large White pigs from a single farm, to address two questions: (1) whether phenotypic associations can be observed between productivity and APP, indicating the effects of possible subclinical infections and (2) whether previous selection for either food intake or ‘lean growth under restricted feeding’ influences APP levels. The APP investigated were alpha1- acid glycoprotein (AGP) and haptoglobin. The APP were measured at 18 and 24 weeks of age in pigs previously selected for high lean growth (no. = 31), low lean growth (no. = 38), high daily food intake (no. = 24) and low daily food intake (no. = 26), but performing under ad libitum feeding conditions. Performance traits and APP levels were constant over the experimental period, indicating that the farm health status did not vary over time. Performance traits and APP were recorded on 119 pigs, of which 80 had both APP and performance measurements. Multiple regression analyses were used to investigate phenotypic relationships between performance traits and APP levels. Plasma concentrations of AGP were higher in 18-week-old pigs compared with 24-week-old pigs (P< 0·01) whereas haptoglobin levels did not vary according to age. Significant sex differences in APP levels were observed. Females had higher circulating levels of AGP than males at both 18 weeks and 24 weeks. Females also had higher levels of haptoglobin at 18 weeks. Levels of AGP had significant negative correlations with daily weight gain (−0·59,P< 0·01 and −0·48,P< 0·05 at 18 and 24 weeks respectively) and with daily food intake (−0·53,P< 0·01 and −0·38,P< 0·05 at 18 and 24 weeks respectively). At age 24 weeks, haptoglobin was negatively correlated with both daily weight gain (−0·35,P< 0·05) and food efficiency (−0·34,P< 0·05). Pigs selected for high lean growth under restricted feeding had higher AGP levels than pigs selected for low lean growth under restricted feeding at 18 (593v. 332 μg/ml,P< 0·01) and 24 weeks of age (313 v. 219 μg/ml,P< 0·05). Selection for daily food intake did not consistently affect AGP levels, and neither selection criteria influenced plasma haptoglobin concentrations. To conclude, we have demonstrated that amongst contemporaneous pigs of the same genotype, higher systemic AGP levels and, to a lesser extent, higher haptoglobin levels are associated with decreased performance, and that genetic selection for ‘efficient lean growth under restricted feeding’ can increase serum AGP levels.

Genotype with feeding regime interaction in pigs divergently selected for components of efficient lean growth rate

1995 ◽  
Vol 61 (1) ◽  
pp. 123-132 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Conversion Ratio ◽  
Restricted Feeding ◽  
Food Conversion ◽  
Feeding Regime ◽  
Lean Growth ◽  
Food Conversion Ratio ◽  
Daily Food ◽  
Feeding Regimes ◽  
Ad Libitum

AbstractThe genotype with feeding regime interaction was examined by testing pigs from four selection groups on both ad libitum and restricted feeding regimes. Within each selection group, there were high, low and control lines, which had been selected for lean food conversion ratio (LFC), daily food intake (DFI) or lean growth rate on ad libitum (LGA) or on restricted (LGS) feeding, in Large White-Edinburgh (LW) and Landrace-Wye (LR) populations. There were 1187 LW pigs and 768 LR pigs in the study, with 344 LW and 133 LR pigs tested on the alternative feeding regime.In the LW population, pigs in the high LGS line grew significantly faster than the high LGA and LFC lines with ad libitum feeding (919 v. 847 and 786 (s.e.d. 31) g/day), but had similar food conversion ratios and backfat depths. The high LGS and high DFI lines were similar for growth rate, daily food intake and food conversion ratio, but backfat depth was significantly lower in the high LGS line than in the high DFI line (12·0 v. 25·9 (s.e.d. 0·7) mm). On restricting feeding, the rankings of the selection lines for growth rate, food conversion ratio and mid-back fat depth were broadly similar to those with ad libitum feeding, except for the high LFC line. In the LR population, the high LGS, LGA and LFC lines did not differ significantly in growth rate, daily food intake, food conversion ratio and backfat depth within either the ad libitum or restricted feeding regimes. Growth rate of the high LGS line was similar to the high DFI line on ad libitum feeding (828 v. 836 (s.e.d. 40) g/day), but significantly higher on restricted feeding (704 v. 636 (s.e.d. 23) g/day). On both feeding regimes, food conversion ratio and backfat depth were significantly lower in the high LGS line compared with the high DFI line.In the LW population, the genetic correlation between feeding regimes for growth rate was significantly less than one (0·4 (s.e. 0·20)), but was not significantly different from unity (0·8 (s.e. 0·14)) for backfat depths. Based on the performance test results, selection for lean growth with testing on a restricted feeding regime may be preferable to testing animals on an ad libitum feeding regime.

Selection for components of efficient lean growth rate in pigs 3. Responses to selection with a restricted feeding regime

1994 ◽  
Vol 59 (2) ◽  
pp. 271-279 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran ◽  
J. C. Kerr
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Environmental Effects ◽  
Genetic Correlations ◽  
Parameter Estimates ◽  
Selection Line ◽  
Restricted Feeding ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food

AbstractResponses to four generations of divergent selection in pigs for lean growth rate (LGS) with restricted feeding were studied. The selection criterion was designed to obtain equal correlated responses in growth rate and carcass lean content, measured in phenotypic s.d. Animals were to be performance tested in individual pens with a mean starting weight of 30 kg for a period of 84 days. Daily food intake was equal to 0·75 gig of the daily food intake for pigs offered food ad-libitum. In the high, low and control lines, there ivere 1250 Large White-Edinburgh (LW) pigs and 875 British Landrace-Wye (LR) pigs. Each selection line consisted of 10 sires and 20 dams, with a generation interval ofl year.After four generations of selection, cumulative selection differentials were 5·9 and 4·8 phenotypic s.d. for LW and LR populations, with similar responses, 1·8 (s.e. 0·17) phenotypic s.d. Mean weight at the end of test, growth rate and backfat depths at the shoulder, mid back and loin were 89 kg, 712 g/day, 26,13 and 13 mm for LW and for LR pigs were 87 kg, 683 g/day, 28,10 and 10 mm. High line pigs were heavier at the end of test (4·3 (s.e.d. 1·4) kg and 4·0 (s.e.d. 1·6) kg) for LW and LR populations, with corresponding responses in growth rate (54 (s.e.d. 16) g/day and 47 (s.e.d. 18) g/day). Responses in the three backfat depths were −4·1 (s.e.d. 1·2) mm, −2·6 (s.e.d. 0·7) mm and −2·9 (s.e.d. 0·7) mm for LW and −2·2 (s.e.d. 0·05) mm, −2·2 (s.e.d. 0·4) mm and −2·4 (s.e.d. 0·5) mm for LR populations. Responses in weight off test and backfat depths were symmetric about the control lines.Heritabilities for LGS were 0·34 and 0·28 (s.e.d. 0·5) for the LW and LR populations, when estimated by residual maximum likelihood. Common environmental effects for LGS were 0·11 (s.e. 0·03) for LW and 0·17 (s.e. 0·04) for LR. Heritabilities for growth rate and average backfat depth were similar for LW and LR populations (0·17 and 0·29, s.e. 0·05), as were common environmental effects (0·10 s.e. 0·04). Average phenotypic and genetic correlations between growth rate and backfat, for LW and LR populations, were small (0·15 (s.e. 0·03) and −0·06 (s.e. 0·16), respectively).Responses to selection and genetic parameter estimates demonstrate that there is substantial genetic variation in growth and fat deposition when pigs are performance tested on restricted feeding.

Responses in gilt post-farrowing traits and pre-weaning piglet growth to divergent selection for components of efficient lean growth rate

1996 ◽  
Vol 1996 ◽  
pp. 17-17
Author(s):  
J. C. Kerr ◽  
N. D. Cameron
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Fixed Time ◽  
Divergent Selection ◽  
Large White ◽  
Lean Growth ◽  
Fixed Weight ◽  
Ad Libitum ◽  
Selection For ◽  
Piglet Growth

Responses in sow traits at farrowing and during lactation and in pre-weaning piglet growth rate were determined in a population of Large White pigs, after seven generations of divergent selection for components of efficient lean growth rate. Information on the factors influencing preweaning piglet growth rate is required for a comprehensive evaluation of alternative selection strategies.There were four selection groups: daily food intake (DFI), lean food conversion (LFC), lean growth rate (LGA) on ad-libitum feeding and lean growth rate on scale feeding (LGS). There were 242 gilts in the study, with 20 gilts in the high, low and control lines of each selection group. Pigs in the ad-libitum selection groups were performance tested over a fixed weight range of 30 to 85 kg. Pigs fed on scale feeding were performance tested for a fixed time period of 84 days from 30 kg with food intake equal to 0.75 g/g of daily ad-libitum food intake. Matings were unsupervised and took place in outside paddocks.

Genotype with feeding regime interaction in pigs

1994 ◽  
Vol 1994 ◽  
pp. 13-13
Author(s):  
N.D. Cameron ◽  
M.K. Curran
Keyword(s):  
Performance Test ◽  
Performance Testing ◽  
High Energy ◽  
Restricted Feeding ◽  
Large White ◽  
Feeding Regime ◽  
Lean Growth ◽  
Fixed Weight ◽  
Ad Libitum ◽  
Alternative Feeding

This paper examined a genotype with feeding regime interaction by performance testing pigs, selected for lean growth on ad-libitum or restricted feeding, on both the normal and the alternative feeding regime.Large White (LW) and Landrace (LR) pigs from divergent selection lines were for four generations for lean growth either on an ad-libitum (LGA) or a restricted (LGS) feeding regime. In each selection group, there were high, low and control lines, which consisted of 10 sires and 20 dams. On average, 3 boars and 3 gilts were tested per litter, with one boar and one gilt per litter tested on the alternative feeding regime. On ad-libitum feeding, there were 181 LGA and 94 LGS LW pigs and 162 LGA and 67 LGS LR pigs. On restricted feeding, 92 LGA and 212 LGS LW and 53 LGA and 135 LGS LR pigs were tested.Performance test. The performance test was over a fixed weight range of 30±3 kg to 85±5 kg for ad-libitum fed pigs and for a fixed time of 84 days for restricted fed pigs. Restricted feeding was equal to 0.75 g/g of daily food intake of ad-libitum fed pigs. All pigs were individually penned and fed a high energy (13.8 MJ DE/kg DM) and high protein (210 g/kg DM crude protein) pelleted ration.

Selection for components of efficient lean growth rate in pigs 4. Genetic and phenotypic parameter estimates and correlated responses in performance test traits with ad-libitum feeding

1994 ◽  
Vol 59 (2) ◽  
pp. 281-291 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Food Conversion ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Daily Food ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Ad Libitum Feeding

AbstractGenetic and phenotypic parameters and correlated responses in performance test traits were estimated for populations of Large White (LW) and British Landrace (LR) pigs tested in Edinburgh and Wye respectively, to four generations of divergent selection for lean growth rate (LGA), lean food conversion (LFC) and daily food intake (DFI) with ad-libitum feeding.There were differences between the two populations in genetic parameters, as LW heritabilities for growth rate, daily food intake and backfat depths were higher and the correlation between growth rate and backfat was positive for LW, but negative for LR. However, heritabilities, genetic and phenotypic correlations were generally comparable between selection groups, within each population. Genetic and phenotypic correlations indicated that animals with high daily food intakes were faster growing, had positive residual food intakes (RFI), were fatter with higher food conversion ratios. RFI was highly correlated with daily food intake and food conversion ratio, but phenotypically independent of growth rate and backfat, as expected.Selection for LGA, in LW and LR populations, increased growth rate (54 and 101 g/day), but reduced backfat (−3·9 and −2·0 mm), food conversion ratio (−0·23 and −0·25) and total food intake (−11·8 and −12·6 kg). There was no change in daily food intake in LW pigs (−19 g/day), but daily food intake increased in the LR pigs (69 g/day). With selection for LFC in LW and LR populations, there was no response in groivth rate (9 and 9 g/day), but backfat (−4·1 and −2·1 mm), total (−6·6 and −11·8 kg) and daily food intake (−90 and −172 g) were reduced, as animals had lower food conversion ratios (−0·13 and −0·22). LW and LR pigs selected for DFI ate more food in total (6·8 and 5·9 kg) and on a daily basis (314 and 230 g), grew faster (94 and 51 g/day) and had higher food conversion ratios (0·12 and 0·13). Backfat was increased in LW pigs (3·7 mm), but not in the LR population.In general, efficiency of lean growth was improved by increasing groivth rate, with little change in daily food intake from selection for LGA, but was primarily due to reduced daily food intake with selection on LFC.

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