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

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.

1992 ◽  
Vol 55 (2) ◽  
pp. 241-246 ◽  
Author(s):  
A. G. de Vries ◽  
E. Kanis

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.


1983 ◽  
Vol 36 (2) ◽  
pp. 193-199 ◽  
Author(s):  
R. G. Campbell ◽  
M. R. Taverner ◽  
D. M. Curic

ABSTRACTForty-two pigs representing equal numbers of entire males and females were used to study the effects on the performance and body composition of four restricted levels of feeding (14·5, 20·3, 24·9 and 29·4 MJ digestible energy per day), and of offering the same diet (14·5 MJ digestible energy per kg and 210 g crude protein per kg) ad libitum between 20 and 45 kg live weight.Over the four restricted feeding treatments there were no significant differences between the sexes for the performance and body composition of four restricted levels of feeding (14·5, 20·3, 24·9 and 29·4 MJ digestible energy per day), and of offering the same diet (14·5 MJ digestible energy per kg and 210 g crude protein per kg) ad libitum between 20 and 45 kg live weight.Although ad libitum energy intake was the same for both sexes (34·2 MJ digestible energy per day), raising digestible energy intake from that provided by the highest restricted feeding treatment (29·4 MJ/day) to ad libitum resulted in marked differences between the sexes for performance and body composition.For males, raising digestible energy intake from 29·3 to 34·2 MJ/day improved the rate of live-weight gain and protein deposition by 0·15 and 0·10 respectively but had no further effect on food conversion ratio or body fat. The same increase in digestible energy intake for females improved growth rate by only 0·065, had no further effect on the rate of protein deposition but increased markedly food conversion ratio and body fat.


1994 ◽  
Vol 42 (1) ◽  
pp. 37-45
Author(s):  
P. Bikker ◽  
M.W.A. Verstegen ◽  
S. Tamminga

In experiment 1, 90 female pigs were fed, from 20 to 45 kg, at two energy intake levels (2x and 3x maintenance requirement) and 15 protein intakes ranging from 127 to 350 g/day. Protein deposition increased linearly with increasing protein intake until a plateau in deposition was reached at 106 and 126 g/day at the low and high energy level, respectively. Marginal efficiency of utilization of ileal digestible lysine was 0.74 for the two energy levels. In a second experiment, 24 female pigs were fed a protein-adequate diet at six levels of energy intake ranging from 1.7x maintenance to ad libitum. Protein deposition increased from 70 to 172 g/day, with increasing feed intake. The proportion of body protein deposited as lean tissue decreased from 0.62 to 0.55 with increasing feed intake. Consequences of these results for a more sustainable animal production are discussed.


1995 ◽  
Vol 46 (2) ◽  
pp. 305 ◽  
Author(s):  
MT Skorupski ◽  
DJ Garrick ◽  
HT Blair ◽  
WC Smith

A computer model simulating life cycle production of a breeding sow and growth performance of her offspring was used to estimate economic values of reproduction and growth performance traits. The model simulated digestion and metabolism of dietary nitrogen in growing pigs (20 to 85 kg), based on the linear/plateau relationship between daily protein deposition and digestible energy intake. Economic values (EVs) of reproduction and growth performance traits were calculated by simulating effects of genetic changes in several biological components, in a farrow-to-finish production system, assuming ad libitum feeding. Results demonstrated that economic values of traits depended on the average genetic merit in the pig herd and its interaction with the management circumstances (level of feeding, nature of the diet, life cycle length) of the production system.


2019 ◽  
Vol 97 (8) ◽  
pp. 3213-3227 ◽  
Author(s):  
Emma T Helm ◽  
Shelby M Curry ◽  
Carson M De Mille ◽  
Wesley P Schweer ◽  
Eric R Burrough ◽  
...  

Abstract Porcine reproductive and respiratory syndrome (PRRS) virus is one of the most economically significant pig pathogens worldwide. However, the metabolic explanation for reductions in tissue accretion observed in growing pigs remains poorly defined. Additionally, PRRS virus challenge is often accompanied by reduced feed intake, making it difficult to discern which effects are virus vs. feed intake driven. To account for this, a pair-fed model was employed to examine the effects of PRRS challenge and nutrient restriction on skeletal muscle and liver metabolism. Forty-eight pigs were randomly selected (13.1 ± 1.97 kg BW) and allotted to 1 of 3 treatments (n = 16 pigs/treatment): 1) PRRS naïve, ad libitum fed (Ad), 2) PRRS-inoculated, ad libitum fed (PRRS+), and 3) PRRS naïve, pair-fed to the PRRS-inoculated pigs’ daily feed intake (PF). At days postinoculation (dpi) 10 and 17, 8 pigs per treatment were euthanized and tissues collected. Tissues were assayed for markers of proteolysis (LM only), protein synthesis (LM only), oxidative stress (LM only), gluconeogenesis (liver), and glycogen concentrations (LM and liver). Growth performance, feed intake, and feed efficiency were all reduced in both PRRS+ and PF pigs compared with Ad pigs (P < 0.001). Furthermore, growth performance and feed efficiency were additionally reduced in PRRS+ pigs compared with PF pigs (P < 0.05). Activity of most markers of LM proteolysis (μ-calpain, 20S proteasome, and caspase 3/7) was not increased (P > 0.10) in PRRS+ pigs compared with Ad pigs, although activity of m-calpain was increased in PRRS+ pigs compared with Ad pigs (P = 0.025) at dpi 17. Muscle reactive oxygen species production was not increased (P > 0.10) in PRRS+ pigs compared with Ad pigs. However, phosphorylation of protein synthesis markers was decreased in PRRS+ pigs compared with both Ad (P < 0.05) and PF (P < 0.05) pigs. Liver gluconeogenesis was not increased as a result of PRRS; however, liver glycogen was decreased (P < 0.01) in PRRS+ pigs compared with Ad and PF pigs at both time points. Taken together, this work demonstrates the differential impact a viral challenge and nutrient restriction have on metabolism of growing pigs. Although markers of skeletal muscle proteolysis showed limited evidence of increase, markers of skeletal muscle synthesis were reduced during PRRS viral challenge. Furthermore, liver glycogenolysis seems to provide PRRS+ pigs with glucose needed to fuel the immune response during viral challenge.


1994 ◽  
Vol 72 (5) ◽  
pp. 938-947 ◽  
Author(s):  
Ann C. Allaye Chan-McLeod ◽  
Robert G. White ◽  
Dan F. Holleman

We used captive caribou (Rangifer tarandus granti) and reindeer (Rangifer tarandus tarandus) to study the effects of energy intake, protein intake, dietary protein:energy ratio, date, and body condition on (i) body fat versus body protein deposition and (ii) maternal tissue deposition versus milk production. Energy intake was the only variable significantly affecting body mass (BM) changes in either breeding or nonbreeding adult females. Lactating and nonlactating females had comparable efficiency coefficients for net energy retention (60 and 65%, respectively), but the daily maintenance requirement for lactating females (457 kJ/BM0.75) was twice that for nonlactating individuals (232 kJ/BM0.75). In both lactating and nonlactating females, the proportion of tissue deposited as fat rather than protein increased between spring and fall but decreased with increasing fatness. Energy intake increased protein deposition in lactating females but increased fat deposition in nonlactating females. Milk water volume increased with maternal energy intake and decreased with calf age. However, production of milk dry matter, milk fat, and milk energy were not affected by maternal energy or protein intake, maternal body condition, or calf age. Production of milk lactose correlated with maternal energy intake, while production of milk protein correlated with the maternal dietary protein:energy ratio.


1995 ◽  
Vol 61 (1) ◽  
pp. 43-55 ◽  
Author(s):  
A. L. Goetsch ◽  
C. L. Ferrell

AbstractCrossbred wethers (34 (s.e. 0·9) kg), with catheters in a hepatic vein, the portal vein and a mesenteric vein and artery, were offered ad libitum alfalfa (A), bermudagrass (B) or ryegrass-wheat (RW) hay and approximately 0, 200 or 400 g/kg maize (dry matter) to determine influences of maize level on net flux of oxygen and nutrients across the portal-drained viscera (PDV) and liver with different forage sources. Digestible energy intake (MJ/day) was 8·5, 12·0 and 12·8 (s.e. VIS) for A; 4·5, 5·5 and 9·0 (s.e. 0·93) for B; and 9·4, 8·8 and 12·2 (s.e. 0·93) for RW with 0, 200 and 400 g/kg maize, respectively. Splanchnic bed oxygen consumption (mmol/h) was 301, 304 and 322 (s.e. 27·2) for A; 178, 187 and 217 (s.e. 30·0) for B; and 226, 133 and 233 (s.e. 19·0) for RW with 0, 200 and 400 g/kg maize, respectively. Increasing dietary maize level linearly increased (P < 0·05) PDV release of alpha-amino nitrogen with B (5, 9 and 14 mmol/h) but not with A or RW. Dietary maize level did not consistently alter PDV or hepatic net flux of urea or ammonia nitrogen, suggesting that changes in ruminally fermentable organic matter from diets offered ad libitum, presumably induced by varying dietary concentrate level, may not alter nitrogen recycling when forage is 86 g/kg or greater in crude protein. Propionate release by the PDV and hepatic uptake increased linearly (P < 0·08) as maize level in A and B diets increased, although increasing dietary maize level did not significantly alter PDV, hepatic or splanchnic bed net flux of glucose regardless of forage source. Nevertheless, glucose concentration in arterial blood with A and RW increased linearly fP < 0·05) with increasing maize level, suggesting increased peripheral glucose availability. In conclusion, the potential to decrease energy consumption by splanchnic tissues relative to digestible energy intake by dietary inclusion of maize, thereby increasing the proportion of absorbed energy available to extra-splanchnic tissues, may be greater for low-quality forage than for forage of moderate or high quality and for moderate v. low dietary levels of maize with low-quality forage.


2020 ◽  
Vol 98 (7) ◽  
Author(s):  
Amy L Petry ◽  
Nichole F Huntley ◽  
Michael R Bedford ◽  
John F Patience

Abstract The experimental objective was to investigate the impact of xylanase on the bioavailability of energy, oxidative status, and gut function of growing pigs fed a diet high in insoluble fiber and given a longer adaptation time than typically reported. Three replicates of 20 gilts with an initial body weight (BW) of 25.43 ± 0.88 kg were blocked by BW, individually housed, and randomly assigned to one of four dietary treatments: a low-fiber control (LF) with 7.5% neutral detergent fiber (NDF), a 30% corn bran without solubles high-fiber control (HF; 21.9% NDF), HF + 100 mg/kg xylanase (HF + XY; Econase XT 25P), and HF + 50 mg/kg arabinoxylan-oligosaccharide (HF + AX). Gilts were fed ad libitum for 36 d across two dietary phases. Pigs and feeders were weighed on days 0, 14, 27, and 36. On day 36, pigs were housed in metabolism crates for a 10-d period, limit fed (80% of average ad libitum intake), and feces and urine were collected the last 72 h to determine the digestible energy (DE) and metabolizable energy (ME). On day 46, serum and ileal and colonic tissue were collected. Data were analyzed as a linear mixed model with block and replication as random effects, and treatment, time, and treatment × time as fixed effects. There was a significant treatment × time interaction for BW, average daily gain (ADG), and gain to feed (G:F; P &lt; 0.001). By design, BW at day 0 did not differ; at day 14, pigs fed LF were 3.5% heavier, and pigs fed HF + XY, when compared with HF, were 4% and 4.2% heavier at days 27 and 36, respectively (P &lt; 0.001). From day 14 to 27 and day 27 to 36, when compared with HF, HF + XY improved ADG by 12.4% and 10.7% and G:F by 13.8% and 8.8%, respectively (P &lt; 0.05). Compared with LF, HF decreased DE and ME by 0.51 and 0.42 Mcal/kg, respectively, but xylanase partially mitigated that effect by increasing DE and ME by 0.15 and 0.12 Mcal/kg, over HF, respectively (P &lt; 0.05). Pigs fed HF + XY had increased total antioxidant capacity in the serum and ileum (P &lt; 0.05) and tended to have less circulating malondialdehyde (P = 0.098). Pigs fed LF had increased ileal villus height, and HF + XY and HF + AX had shallower intestinal crypts (P &lt; 0.001). Pigs fed HF + XY had increased ileal messenger ribonucleic acid abundance of claudin 4 and occludin (P &lt; 0.05). Xylanase, but not AX, improved the growth performance of pigs fed insoluble corn-based fiber. This was likely a result of the observed increase in ME, improved antioxidant capacity, and enhanced gut barrier integrity, but it may require increased adaptation time to elicit this response.


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