A growth model to estimate economic values for food intake capacity in pigs

1992 ◽  
Vol 55 (2) ◽  
pp. 241-246 ◽  
Author(s):  
A. G. de Vries ◽  
E. Kanis
Keyword(s):  
Food Intake ◽  
Growth Model ◽  
Economic Value ◽  
Growing Pigs ◽  
Production Costs ◽  
Economic Values ◽  
Biological Growth ◽  
Protein Deposition ◽  
Positive Economic ◽  
Ad Libitum

AbstractA biological growth model was developed to study economic values for average ad libitum food intake capacity (FIC) in growing pigs. The model was based on the linear/plateau relationship between protein deposition and food intake. Input variables were: minimum fat to protein deposition ratio (R), maximum protein deposition rate (Pdmax)and food intake (FI). Output variables were production traits and production costs.Economic values (under commercial conditions with ad libitum feeding) were derived with the growth model for each of the traits FIC, R, and Pdmax keeping the other two traits constant, for three alternative levels of FIC. If FIC was too low to realize Pdmax, FIC had a positive economic value, R had a negative economic value and the value of Pdmax was zero. If FIC was higher than necessary to realize Pdmax, economic values were negative, zero and positive for FIC, R, and Pdmax respectively. If FIC was just sufficient to realise Pdmax, the lowest production costs occurred. Now, R had a negative economic value and Pdmax had a positive economic value.With a restricted feeding regimen under commercial conditions a daily food supply just sufficient to realize Pdmax should be pursued. It was concluded that use of a biological growth model to estimate economic values for FIC would give more insight into correct selection strategies than would the use of an economic model.

Economic values of traits for pig improvement. I. A simulation model

1995 ◽  
Vol 46 (2) ◽  
pp. 285 ◽  
Author(s):  
MT Skorupski ◽  
DJ Garrick ◽  
HT Blair ◽  
WC Smith
Keyword(s):  
Life Cycle ◽  
Growth Performance ◽  
Energy Intake ◽  
Growth Model ◽  
Growing Pigs ◽  
Economic Values ◽  
Body Protein ◽  
Digestible Energy ◽  
Protein Deposition ◽  
Ad Libitum

A computer model simulating life cycle production of a breeding sow and growth performance of her offspring was developed to estimate economic values of reproduction and growth performance traits. A biological growth model, simulating the digestion and metabolism of dietary nitrogen in growing pigs (20 to 85 kg), was part of the life cycle model. The growth model was based on the linear/plateau relationship between daily protein deposition and digestible energy intake. A farrow-to-finish production system, with slaughter pigs marketed at fixed liveweights, was simulated. Input variables were: gilt age at first oestrus, weaning to oestrus interval, number of pigs born alive per litter, and pre-weaning mortality for each parity. Economic inputs included prices of feed ingredients, carcass returns and non-feed costs. The upper limit to body protein deposition rate, mean daily ad libitum digestible energy intake and minimum lipid to protein deposition ratio were assumed the major genetic determinants of pig growth. The model output included average daily gain, ad libitum daily feed intake, backfat thickness, and life cycle reproductive performance and profit. The combined life cycle profit was expressed in the form of an Annualized Present Value. Life cycle profit was calculated for a range of simulated pig genotypes.

Two growth models to estimate economic values for food intake capacity in pigs

1999 ◽  
Vol 69 (1) ◽  
pp. 49-57 ◽  
Author(s):  
P. von Rohr ◽  
A. Hofer ◽  
N. Künzi
Keyword(s):  
Food Intake ◽  
Growth Models ◽  
Average Daily Gain ◽  
Economic Value ◽  
Production Costs ◽  
Production Model ◽  
Economic Values ◽  
Protein Deposition ◽  
Selection Responses ◽  
Economic Production

AbstractEconomic values for average ad libitum food intake capacity (FIC) were estimated with two different linear-plateau models. One model based on a constant minimum fat to protein deposition ratio (Rmin). The other model relied on a constant minimum marginal ratio between fat and protein deposition (MR). Economic values were used to define aggregate genotypes where the driving variables of the growth models were considered as traits. The consequences of a possible implementation of such aggregate genotypes were evaluated with a comparison of the expected selection responses for the different traits.Economic values for the traits under the two models indicated the same direction of selection and differed only slightly in their magnitude. For a FIC below its optimum, FIC had a positive and Rmin or MR a negative, economic value. In this situation the maximum protein deposition rate Pdmax had no influence on the production costs and therefore an economic value of zero. Selection emphasis is then mainly put on FIC which leads to an increase in average daily gain (ADG). If FIC is above its optimum, economic values for FIC were negative, positive for Pdmax and equal to zero for Rmin or MR. Practically no differences between the selection responses under the two growth models were observed.The use of growth models to estimate economic values for FIC allowed to attribute a positive economic value to this trait if it is below its optimum. This is not possible when economic values are estimated with an economic production model.

Amino acid and energy interactions in growing pigs 1. Effects of food intake, sex and live weight on the responses of growing pigs to lysine concentration

1985 ◽  
Vol 40 (2) ◽  
pp. 331-343 ◽  
Author(s):  
E. S. Batterham ◽  
L. R. Giles ◽  
E. Belinda Dettmann
Keyword(s):  
Food Intake ◽  
Analysis Of Variance ◽  
Live Weight ◽  
Response Surfaces ◽  
Growing Pigs ◽  
Large White ◽  
Lysine Concentration ◽  
Males And Females ◽  
Ad Libitum ◽  
Daily Gain

ABSTRACTThe responses of growing pigs to dietary lysine concentration, as influenced by food intake, sex (intact males and females) and live weight were investigated in a 4 x 2 x 2 x 2 factorial experiment involving 128 Large White pigs. Lysine concentrations were 7, 8, 9 and 10 g/kg air-dry food. The basal wheat-soya bean meal diet (14·0 MJ digestible energy per kg) was offered either ad libitum or on a restricted feeding scale to pigs from 20 to 85 kg live weight. During the 50 to 85 kg growth phase, the effects of proportionately reducing the lysine concentrations by 0·2 were investigated. Performance response was assessed in two ways; by analysis of variance for the 20 to 50, 50 to 85 and 20 to 85 kg phases, and by response surface analyses of data from successive 10-kg weight intervals.An initial analysis of variance indicated that food intake (of pigs fed ad libitum), daily gain and food conversion ratio varied with lysine concentration, but that the responses differed with food intake, sex and phase of growth.Analysis of the response surfaces delineated by lysine level and phase of growth indicated that for males and females with restricted food and males fed ad libitum, maximum daily gain was produced by feeding at least 10 g lysine per kg, declining to about 8 g/kg at 80 kg. With females fed ad libitum, maximum daily gain was obtained by feeding 9·9 g lysine per kg at 20 kg, declining to less than 5·6 g/kg at 75 kg.Carcass characteristics were largely unaffected by lysine concentration.

The effect of group size on the performance of growing pigs

1989 ◽  
Vol 49 (3) ◽  
pp. 497-502 ◽  
Author(s):  
J. Carol Petherick ◽  
A. W. Beattie ◽  
D. A. V. Bodero
Keyword(s):  
Food Intake ◽  
Group Size ◽  
Significant Interaction ◽  
Significant Positive Correlation ◽  
Growing Pigs ◽  
Food Conversion ◽  
Space Allocation ◽  
Weight Gains ◽  
Group Members ◽  
Ad Libitum

ABSTRACTThree replicates of three group sizes (six, 18 and 36) of grower pigs were housed with the same space allocation (0·66 m2 per pig), feeding and drinking space per animal. The animals were mixed and kept together for a period of 22 days. They were given food ad libitum, were weighed weekly and a record kept of the group food intake for the 22-day period. Weight at mixing had a significant effect on weight gains during the 1st week. There was a significant interaction between group size and replicates for weight gains; generally weight gains were lowest in the group size of 36 animals during the first 2 weeks, but in the 3rd week there was no difference between the group sizes. Sex had no effect on weight gains. The variation in weights between group members were significantly greater in the group size of 36 than in the group sizes of six and 18 at the start of the trial, but at the end of the trial there was no difference in the variances of weights in the three group sizes. There was no difference between the group sizes in the variances of the weight gains. There was a significant positive correlation (r = +0·36) between weight at mixing and weight gain for the group size of 18. Group size had no effect on food intake, but the food conversion efficiency of the animals in the group size of 36 was significantly poorer than in the group sizes of six and 18.

Optimization of selection for food intake capacity in pigs

1992 ◽  
Vol 55 (2) ◽  
pp. 247-255 ◽  
Author(s):  
E. Kanis ◽  
A. G. de Vries
Keyword(s):  
Food Intake ◽  
Selection Index ◽  
Growing Pigs ◽  
Daily Weight Gain ◽  
Production Traits ◽  
Model Calculations ◽  
Term Selection ◽  
Protein Deposition ◽  
Optimum Selection ◽  
Economic Weight

AbstractOptimum selection directions for averagead libitumfood intake capacity (FIC) in growing pigs were derived by means of a biological growth model based on the linear/plateau relationship between protein deposition and food intake. Breeding goal traits were minimum fat to protein deposition ratio (R), maximum protein deposition rate (Pdmax) and FIC. The selection index included FIC, daily weight gain (DG), backfat thickness and proportion of lean meat in the carcass of a full-sib.Selection indexes were developed for three alternative levels of FIC. If FIC was too low to realize Pdmax, the economic weight of FIC was positive and optimal selection emphasis should be mainly on FIC, resulting in a rapid increase of DG. If FIC was higher than necessary to realize Pdmax, the economic weight of FIC was negative, and short-term selection resulted in increase of carcass leanness but decrease of FIC and DG. If FIC was just sufficient to realize Pdmax, selection should be for R and Pdmax. In this third alternative, the gain in FIC should follow the gain in R and Pdmaxin an optimal way and selection should best be carried out with a desired gains index, which results in improvement of DG and carcass leanness.It was shown that, in cases where FIC was higher than necessary to realize Pdmax, selection with a desired gainsindex should be preferred because this was more profitable in the long term. From the model calculations, it followed that future profit from selection of growing pigs for production traits is likely to decline because of the necessity to increase FIC.

Effect of ambient temperature on energy metabolism in growing pigs

1987 ◽  
Vol 44 (3) ◽  
pp. 427-433 ◽  
Author(s):  
J. M. F. Verhagen ◽  
A. A. M. Kloosterman ◽  
A. Slijkhuis ◽  
M. W. A. Verstegen
Keyword(s):  
Critical Temperature ◽  
Energy Metabolism ◽  
Food Intake ◽  
Ambient Temperature ◽  
Growing Pigs ◽  
Initial Exposure ◽  
Maintenance Requirement ◽  
Lower Critical Temperature ◽  
Two Temperatures ◽  
Ad Libitum

ABSTRACTGroup-housed young growing pigs, given food ad libitum, were exposed to two temperatures, one within thermal neutrality (25°C) and one around the lower critical temperature (15°C). Pigs at 15°C had daily gains reduced by 57 g for 6 days after initial exposure. Food intake was increased significantly after 6 days at 15°C but not at 25°C. Maintenance requirement was increased by 58 kJ/kg M0·75 and energy retained as protein was decreased by 49 kJ/kg M0·75 for the first 6 days after exposure to the treatment of 15°C and thereafter both became equivalent to those of pigs at 25°C afterwards. It is concluded that animals were acclimatized after 6 days exposure.

Modelling the effect of high, constant temperature on food intake in young growing pigs

2001 ◽  
Vol 72 (3) ◽  
pp. 519-527 ◽  
Author(s):  
A. Collin ◽  
J. van Milgent ◽  
J. Le Dividich
Keyword(s):  
Food Intake ◽  
High Temperatures ◽  
Indirect Effects ◽  
Low Temperatures ◽  
Environmental Temperature ◽  
Growing Pigs ◽  
Ad Libitum ◽  
The Difference ◽  
Linear Decline ◽  
High Constant Temperature

AbstractPerformance in pigs is greatly reduced during periods of heat stress through a reduction in voluntary food intake (VFI). However, little information is available as to what extent growth in piglets is affected by high temperature. The objective of this study was therefore to quantify the change in VFI as affected by environmental temperature. Piglets, initially 15·5 (s.e. 1·9) kg body weight (BW), were individually housed and exposed over a period of 17 days to either 19, 21, 23, 25, 27, 29, 31, 33, or 35ºC. Animals had ad libitum access to a starter diet and water. VFI was measured daily whereas BW was determined twice weekly. Over the 17 days, daily VFI and BW gain were proportionately 0·48 and 0·51 lower at 35ºC than at 19ºC. Due to the reduced VFI at high temperatures, the average BW during the experiment was greater at low temperatures than at high temperatures. Consequently, part of the difference in VFI is directly due to temperature and part may be explained by cascading, indirect effects (i.e. the increased BW). To account for this, VFI was expressed as a power function of BW (VFI = aBWb). It was assumed that environmental temperature affected the scalar (a) through a quadratic or a ‘plateau-linear decline’ function of temperature. The VFI appeared relatively constant between 19 and 25ºC (0·096 (kg/day)/(kg BW0·83)) and decreased thereafter. Between 25 and 35ºC, VFI decreased on average by proportionately 0·28 in a 20-kg pig.

Effect of food intake capacity on genotype by feeding regimen interactions in growing pigs

1990 ◽  
Vol 50 (2) ◽  
pp. 343-351 ◽  
Author(s):  
E. Kanis
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Live Weight ◽  
Tissue Growth ◽  
Growing Pigs ◽  
Fatty Tissue ◽  
Restricted Feeding ◽  
Production Traits ◽  
Feeding Regimen ◽  
Ad Libitum

ABSTRACTFrom each of 159 litters, between one and three pigs were fed ad libitum and between one and four pigs were fed at several restricted feeding levels from about 27 to 107 kg live weight. Effects of litter by feeding regimen (ad libitumv. restricted feeding) interactions (L × F) and sex by feeding regimen interactions (S × F) on production traits were investigated. In experimental groups where restrictedly fed animals received an amount of food based on their estimated voluntary food intake capacity (FIC), interactions were non-significant. In groups where restricted feeding was independent of FIC, significant L × F or S × F interactions were found for daily food intake (FI), daily gain, lean tissue growth rate and fatty tissue growth rate, but not for body composition and food conversion traits.Because of between-animal variation in FIC, restricted feeding according to a fixed scale restricted intake of some animals to a higher degree than others and degree of food intake restriction (DFR) was calculated from actual FI and FIC for animals fed at a restricted level. After correction of FI and production traits of restrictedly fed animals for differences in DFR, L × F and S × F interactions were not significant.It was concluded that the poor relationships often found between test-station results of boars and results of their progeny in practical environments may be caused, to an important extent, by differences in DFR in each environment. To overcome these genotype by environment interactions it is recommended that animals be fed ad libitum in both test and commercial environments.

Amino acid and energy interactions in growing pigs 2. Effects of food intake, sex and live weight on responses to lysine concentration in barley-based diets

1986 ◽  
Vol 42 (1) ◽  
pp. 133-144 ◽  
Author(s):  
L. R. Giles ◽  
E. S. Batterham ◽  
E. Belinda Dettmann
Keyword(s):  
Food Intake ◽  
Live Weight ◽  
Soya Bean ◽  
Growing Pigs ◽  
Restricted Feeding ◽  
Growth Phases ◽  
Lysine Concentration ◽  
Ad Libitum ◽  
Daily Gain ◽  
Entire Male

ABSTRACTThe responses of growing pigs to dietary lysine concentration, as influenced by food intake, sex (entire male and female) and live weight were investigated in an experiment involving 128 pigs. The basal barley-soya-bean diet (14·2 MJ digestible energy (DE) per kg) was offered either ad libitum or according t o a restricted feeding scale to both sexes from 20 to 85 kg live weight. The eight dietary lysine concentrations ranged from 8·0 to 12·2 g/kg during the 20 to 50 kg phase and from 6·4 to 9·8 g/kg during the 50 to 85 kg live-weight phase. Performance was assessed by response-surface analysis based on data from successive 10-kg live-weight intervals. Regression analysis was used to assess the response of carcass lean content after slaughter at 85 kg live weight.Daily gain of females fed ad libitum was curvilinear up to maxima of 0·72 and 0·69 g lysine per MJ DE during the 20 to 50 and 50 to 85 kg growth phases respectively. Daily gain response was small but linear up to the maximum dietary lysine concentration for all other combinations of sex and food intake.The response of carcass lean for males given food at a restricted level was linear up to the maximum dietary lysine concentration. For males given food ad libitum, carcass lean response was curvilinear with maximum lean content attained with 0·73 and 0·59 g lysine per MJ DE during the 20 to 50 and 50 to 85 kg live-weight phases respectively. Carcass lean content of females was not affected by lysine concentration within the range used.

Modelling the relation between energy intake and protein and lipid deposition in growing pigs

2000 ◽  
Vol 71 (1) ◽  
pp. 119-130 ◽  
Author(s):  
J. van Milgen ◽  
N. Quiniou ◽  
J. Noblet
Keyword(s):  
Energy Requirement ◽  
Growing Pigs ◽  
The Other ◽  
Maintenance Energy ◽  
Lipid Deposition ◽  
Large White ◽  
Protein Deposition ◽  
Ad Libitum ◽  
Maintenance Energy Requirement ◽  
Ad Libitum Intake

AbstractWhen modelling the effect of a changing nutrient supply to growing animals, it is important to distinguish the individual response curve of an animal from the change in this response that may occur during growth. A data analysis model is proposed where, for an individual animal, the relation between protein deposition (PD) and metabolizable energy (ME) intake above maintenance (MEp) is curvilinear, so that PD intersects the origin and reaches its maximum at the maximum protein deposition rate (PDmax). An increase of MEp beyond that required to attain PDmax would not change PD. The MEp not used for protein synthesis can be used for lipid deposition (LD). The relation between PD and LD on the one hand and ME on the other hand can then be described as a function of the maintenance energy requirement (MEm), PDmax, the level of ME required to attain PDmax (F; as a multiple of MEm) and the energetic efficiencies of PD (kp) and LD (kf). Of these statistics, only kp and kf were assumed to be independent of body weight (BW), age or genotype. Variation in PDmax was described as a Gompertz function (of age) whereas variation in F was assumed a linear function of BW. Maintenance energy requirement was expressed as a power function of BW. To evaluate the model, 145 nitrogen and energy (indirect calorimetry) balances were obtained from three types of pigs (Large White castrated males (cLW) and Piétrain × Large White castrated males (cPP× ) and males (bPP×)) ranging in BW between 45 and 100 kg and housed under thermoneutral conditions. Animals were allotted to one of four energy levels ranging from 0·70 to 1·00 of ad libitum intake. The MEm was not different between genotypes (849 kJ/kg BW0·60) whereas the kp and kf were 0·56 and 0·75, respectively. For castrated animals on ad libitum intake, PDmax started limiting PD at approximately 130 days of age (78 and 86 kg BW for cLW and cPP×, respectively). Before this age and for bPP×, PD was limited by MEp. In bPP×, the difference between PD and PDmax was small (less than proportionately 0·05). The F did not change with BW for bPP× (2·85 × MEm) whereas for the other genotypes, it decreased linearly from 4·47 at 45 kg to 2·00 at 100 kg of BW. Due to its nature, the model allows estimation of PDmax even when energy is restricting PD.

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