The performance of Hereford × Friesian offspring of bulls selected for lean growth rate and lean food conversion efficiency

1992 ◽  
Vol 54 (1) ◽  
pp. 23-30 ◽  
Author(s):  
S. C. Bishop ◽  
J. S. Broadbent ◽  
R. M. Kay ◽  
I. Rigby ◽  
A. V. Fisher
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Genetic Correlations ◽  
Conversion Ratio ◽  
Carcass Composition ◽  
Control Line ◽  
Food Conversion ◽  
Breeding Values ◽  
Lean Growth ◽  
Food Conversion Ratio

AbstractThe performance of Hereford × Friesian calves sired by Hereford bulls selected for either lean growth rate (LGR) or lean food conversion ratio (LFCR), or by unselected Hereford bulls, was evaluated on 327 calves on three farms over 2 years. Animals started test at 130 days of age on average and remained on test for approximately 300 days, whereupon all animals were slaughtered and carcass dissections were undertaken. Individual food intake was measured on tioo of the farms (189 animals), but only intake per pen of animals was measured on the third farm and individual food intake had to be estimated. LGR, LFCR and other traits describing performance were calculated from the growth, food intake and carcass composition data.If no breed or environment interactions exist it is expected that proportionately 0-5 of the genetic differences between selected and control line bulls would be transmitted to their offspring. For the LGR and LFCR line bulls these values were 0·38 and 0·44, respectively, however the LGR value had a much smaller confidence interval. Genetic correlations derived from regressing breeding values predicted from offspring performance on breeding values predicted from the bulk's own performance in the selection experiment were 0·62 (s.e. 0·28) and 0·96 (s.e. 0·28) for LGR and LFCR, respectively. Heritabilities were: live-weight gain on test, 0·27; daily gain, 0·48; food intake, 0·06; food conversion ratio, 0·46; predicted carcass lean content, 0·10; killing-out proportion, 0·10; LGR, 0·36 and LFCR, 0·48.

Genetic variation in measures of food efficiency in pigs and their genetic relationships with growth rate and backfat

1993 ◽  
Vol 56 (2) ◽  
pp. 225-232 ◽  
Author(s):  
R. A. Mrode ◽  
B. W. Kennedy
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Genetic Correlations ◽  
Conversion Ratio ◽  
Maximum Likelihood Estimates ◽  
Food Conversion ◽  
Daily Food Intake ◽  
Lean Growth ◽  
Food Conversion Ratio ◽  
Daily Food

AbstractData on 3783 Yorkshire, 2842 Landrace and 937 Duroc littermate pairs of boars, station tested between 1976 and 1989, were used to measure genetic parameters of average daily gain (ADG) from 30 to 90 kg, live backfat at 90 kg (BF), estimated lean growth rate (LGR), average daily food intake, food conversion ratio (FCR) and lean food conversion ratio (LFCR), as well as measures of residual daily food intakes over and above requirements for growth and lean growth. A method was developed to obtain restricted maximum likelihood estimates of genetic variances and covariances under an animal model when observations are on the means of sib pairs. Heritabilities of ADG, BF, LGR, FCR and LFCR were 0·43, 0·59, 0·39, 0·28 and 0·34, respectively. Heritability of daily food intake was 0·45, and heritability of measures of residual daily food intake ranged from 0·30 to 0·38. About half of the variation in daily food intake was residual (0·48 to 0·56). Genetic correlations of ADG with daily food intake, FCR and LFCR were 0·80, −0·28 and −0·09, respectively, and were small and positive (0·18 to 0·34) with measures of residual daily food intake. Backfat had genetic correlations of 0·42, 0·24 and 0·52 with daily food intake, FCR and LFCR, respectively, and genetic correlations between backfat and measures of residual daily food intake ranged from 0·15 to 0·61. Selection against residual food intake may be a useful means of improving efficiency of food utilization.

Selection for components of efficient lean growth in Landrace pigs

1994 ◽  
Vol 1994 ◽  
pp. 10-10
Author(s):  
M.K. Curran ◽  
N.D. Cameron
Keyword(s):  
Growth Rate ◽  
Selection Criteria ◽  
Conversion Ratio ◽  
Control Line ◽  
Food Conversion ◽  
Lean Growth ◽  
Food Conversion Ratio ◽  
Daily Food ◽  
Selection For ◽  
One Year

To study responses to divergent selection for lean growth rate (LGA), lean food conversion ratio (LFC) and daily food intake (DFI), an experiment was started in 1984 at Edinburgh and Wye. 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 Landrace pigs after four generations of selection.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 32, 29 and 270 units and results are presented in s.d. units.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 population consisted of 20 sires and 89 dams. Within each of the three selection groups, there were high and low selection lines with a control line, each consisting of 10 boars and 20 gilts, with a generation interval of one year. There were two control lines, one for LGA and one for LFC and DFI, as selection groups were arrowed continuously. The total number of pigs tested per line and average inbreeding coefficient at generation 4, within selection group are given below.

Genetic relationships between growth and food intake in performance tested ram lambs

1988 ◽  
Vol 1988 ◽  
pp. 31-31
Author(s):  
N.D. Cameron
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Genetic Relationships ◽  
Conversion Ratio ◽  
Food Conversion ◽  
Lean Growth ◽  
Food Conversion Ratio ◽  
Selection Indices ◽  
Ram Lambs ◽  
Terminal Sire

Efficient lean growth may, in future, be the main selection objective in terminal sire breeds of sheep. The genetic relationships between growth rate, food intake and food conversion ratio need to be quantified, so that calculation of selection indices for growth rate and carcass lean content can take account of correlated changes in food intake.

Management strategies to maximize pigmeat output: effect of group size and split-marketing

2005 ◽  
Vol 81 (1) ◽  
pp. 171-177 ◽  
Author(s):  
M. K. O'Connell ◽  
P. B. Lynch ◽  
J. V. O'Doherty
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Group Size ◽  
Unit Area ◽  
Live Weight ◽  
Conversion Ratio ◽  
Carcass Weight ◽  
Food Conversion ◽  
Food Conversion Ratio ◽  
2D And 3D

AbstractTwo experiments were completed with grower-finisher pigs to determine if pigmeat output, as measured by carcass gain per m2 per year, could be increased, by 1: increasing group size or 2: split-marketing pen groups. In experiment 1, 390 pigs (mean initial live weight 36·7 (s.d. 1·99) kg) were assigned to one of three treatments each with 10 replicates: 11, 13 or 15 pigs per single-sex group in pens measuring 11·04 m2. Space allowance was 1·00, 0·85 and 0·74 m2 per pig, respectively. Pelleted food was provided ad libitum. There were no differences (P > 0·05) between group sizes in growth rate, food intake, food conversion ratio, carcass growth and carcass food conversion ratio, backfat and muscle depth or carcass lean content. Pigmeat output per unit area increased with each increase in group size (234, 279 and 314 kg/m2 per year for 11, 13 and 15 pigs: P < 0·001). In experiment 2, 26 groups of 13 pigs (mean initial live weight 38·3 (s.d. 2·15) kg) were assigned to one of three treatments: 1D - group sold on 1 day (no. = 9), 2D - group sold over 2 days (14 days apart, no. = 10), or 3D - group sold over 3 days (each 7 days apart, no. = 7). Pigs were given a standard liquid diet three times daily. No differences (P > 0·05) were observed between treatments for overall growth rate, food intake, food conversion ratio, carcass weight, carcass lean content, backfat and muscle depth, carcass growth and carcass food conversion ratio or killing-out proportion of pigs. Split-marketing increased cycle length (67·7, 75·9 and 76·8 days for 1D, 2D and 3D, respectively; P < 0·001). Live and carcass daily growth rates per pig place decreased with increase in number of sale days (live: 772, 680, 670 g/day and carcass: 658, 575, 571 g/day; P < 0·001). Carcass gain per unit area decreased in split-marketed groups (358, 318, 312 kg/m2 per year for 1D, 2D and 3D, respectively: P < 0·05). Carcass weight variation (s.d.) within pen decreased with each increase in number of sale days (s. d. 5·28, 3·81 and 1·74, respectively; P < 0·001). In conclusion, pigmeat output, as measured by carcass gains per m2 per year, was improved with increase in group size and by marketing all pigs in a group on a single day.

Selection for components of efficient lean growth in Large White pigs

1994 ◽  
Vol 1994 ◽  
pp. 9-9
Author(s):  
N.D. Cameron
Keyword(s):  
Growth Rate ◽  
Selection Criteria ◽  
Conversion Ratio ◽  
Food Conversion ◽  
Correlated Responses ◽  
Large White ◽  
Lean Growth ◽  
Food Conversion Ratio ◽  
Daily Food ◽  
Selection For

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.

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 2. Selection pressure applied and direct responses in a Landrace herd

1994 ◽  
Vol 59 (2) ◽  
pp. 263-269 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Genetic Correlations ◽  
Correlated Response ◽  
Selection Line ◽  
Control Line ◽  
Direct Response ◽  
Lean Growth ◽  
Ad Libitum ◽  
Selection For ◽  
Ad Libitum Feeding

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.

Selection for efficient lean growth in a pig herd

1981 ◽  
Vol 32 (4) ◽  
pp. 681 ◽  
Author(s):  
CP McPhee
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Performance Test ◽  
Subcutaneous Fat ◽  
Performance Testing ◽  
Restricted Feeding ◽  
Food Conversion ◽  
Muscle Area ◽  
Eye Muscle ◽  
Lean Growth

A pig herd was selected for 6 years by using an economic index combining growth rate, food conversion efficiency and carcass leanness. These three traits were all measured in a performance test which permitted appetite variation between pigs to be expressed. Boars selected with an intensity of 118 were used for 6 months, and sows with an intensity of 114 were kept for two farrowings. An unselected control herd was maintained concurrently. To measure selection response, selected (S) and control (C) pigs were compared as they grew from 25 to 90 kg liveweight on ad lib. and restricted feeding during the last 2 years of selection. The following significant (P < 0.05) responses occurred in the selection herd: (i) A slight increase in growth rate on restricted feed, balanced by a similar decrease on ad lib, feeding. (ii) A decline in food conversion ratio of 5 % (C, 2.79; S, 2.65) due mainly to a reduction in appetite. (On ad lib. feeding, food intake per day declined by 6 % (C, 2.30 kg/d; S, 2.16 kg/d.)). (iii) A decline in average subcutaneous fat depth by 11 % (C, 27.8 mm; S, 24.7 mm) and in fat dissected from the ham by 7 % (C, 2.80 kg; S, 2.61 kg). (iv) An increase in estimated lean in the carcass by 2% (C, 30.3 kg; S, 31.0 kg). (v) A decline in dressing percentage of the carcass by 1 % (C, 77.1 %; S, 76.2 %). There was no change in eye muscle area or carcass length. The results are discussed in terms of changes in the ratio of food intake to lean growth. In the group fed ad lib., this ratio declined by 7 %, mainly because of a decline in food intake. On restricted feeding it fell by 6 %, mainly owing to an increase in lean growth. That portion of the selection effort absorbed in reducing food intake may have been more profitably directed to increasing lean growth by suppressing appetite variation during performance testing, rather than allowing it to be expressed.

The association of food conversion ratio, age at slaughter and carcass quality in pigs fed ad libitum

1969 ◽  
Vol 11 (3) ◽  
pp. 317-324 ◽  
Author(s):  
J. B. Owen ◽  
J. R. Morton
Keyword(s):  
Genetic Correlations ◽  
Conversion Ratio ◽  
Residual Effects ◽  
Progeny Testing ◽  
Restricted Feeding ◽  
Food Conversion ◽  
Large White ◽  
Related Factors ◽  
Food Conversion Ratio ◽  
Ad Libitum

SUMMARYData from a boar progeny testing scheme based on ad libitum feeding were analysed to test the hypothesis that the resultant correlations of food conversion ratio with related factors would differ from those found under conditions of restricted feeding.The results support the hypothesis, showing that the primarily genetic correlations derived from boar effects for growth and conversion ratio, are lower than those reported elsewhere for restricted feeding. It was also shown that these primarily genetic correlations could vary between breeds, the leanness associated with rapid growth in Wessex not being found in Large White, and that the correlations due to residual effects containing a greater environmental component varied widely from test to test.It is concluded that the parameters used in the design of a genetic improvement scheme should be derived specifically for each breed and feeding system. However, if the marked variability in phenotypic correlations noted here is generally applicable, this could present a difficult problem in the design of pig improvement programmes with multiple objectives.

Effect of nutrient density and group size on the performance of growing and finishing pigs given food using single-space feeders

2000 ◽  
Vol 71 (2) ◽  
pp. 281-288 ◽  
Author(s):  
J. V. O’Doherty ◽  
M. P. McKeon
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Carcass Characteristics ◽  
Dietary Treatment ◽  
Conversion Ratio ◽  
Finishing Pigs ◽  
Food Conversion ◽  
Nutrient Density ◽  
Daily Food ◽  
Main Effects

AbstractA 2 ✕ 2 ✕ 3 factorial arrangement of treatments used 522 boars to examine the main effects and interactions of season (spring v. summer), number of pigs per pen with a single-space feeder (13 or 16 pigs per pen with a singlespace feeder; 0·78 m2 per pig v. 0·65 m2 floor space per pig) and nutrient density of the diet (12·5 g lysine per kg and 14·0 MJ digestible energy (DE) per kg from 38 kg to slaughter (high), 12·5 g lysine per kg and 14·0 MJ DE per kg during the growing phase and 10·0 g lysine per kg and 13·6 MJ DE per kg during the finishing phase (split) and 10 g lysine per kg and 13·6 MJ DE per kg from 38 kg to slaughter (low)) on the performance and carcass characteristics of growing and finishing pigs. The smaller group of pigs had a higher food intake during the grower-finisher period than the high stocked pigs (P < 0·01). The pigs had a higher lysine intake in the spring than in the summer months (P < 0·05). Differences in daily food intake for the smaller group of pigs were reflected in increased growth rate during the grower-finisher period (P < 0·001). However these pigs had a poorer food conversion ratio during the grower-finisher period (P < 0·05) than the bigger group of pigs. The pigs offered the high specification and split-fed diets had better growth rate (P < 0·05) than the pigs given the low specification diet during the grower and finisher period. There was a significant two-way interaction in growth rate between dietary treatment and season during the finisher period (P < 0·01). The pigs given the high specification diet had a better growth rate (P < 0·001) than the pigs given the low diets during the summer months. However, the high specification diet depressed growth rate during the spring months (P < 0·05). The pigs had a lower backfat and higher lean meat in the summer than in the spring months (P < 0·05).

Sign in / Sign up

Export Citation Format

Share Document