From the feeding plans (Tables 5 and 6) the average daily intake of feed for each ration and each period is calculated and indicated in Tables 16,17 and 18 together with the mean values for live weight in the different periods. The intake of metabolizable energy has been determined for each pig in each balance period, and from these individual values (Main tables p. 159) the mean values are calculated and shown in the same tables.
Table 16. Daily intake of feed and energy in the experiments with barley. Series C-D-E-F.
Mean of 12 pigs in each group
Tabel 16. Daglig optagelse af foder og energi i forsøgene med byg. Serie C-D-E-F.
Middel af 12 svin i hver gruppe
Period
no.
I II HI IV
v.
VI VII VIII
Barley and skim-milk powder Live
weight kg
23 7 . . . 29.3 35 7 . . . 43.3 52 3 . . . 61 4 . . . 72.6 83 1
Daily intake of Feed
kg
0.81 1.02 1.21 1.48 1.78 2.08 2.36 2.66
ME Meal
2.66 3.38 4.02 4.88 5.87 6.80 7.74 8.66
NEF*) Meal
1.84 2.32 2.76 3.32 3.95 4.58 5.16 5.79
Live weight
kg
23.4 28.7 34.7 42.8 50.9 59.6 69.6 80.2
Barley and protein mixture Daily intake of Feed
kg
0.81 1.02 1.21 1.48 1.78 2.08 2.36 2.66
Mb Meal
2.49 3.15 3.75 4.60 5.64 6.51 7.42 8.35
NEF*) Meal
1.69 2.13 2.54 3.11 3.74 4.37 4.95 5.58
*) Calculated from Nehring et al. Futtermitteltabellenwerk. (1970)
The intake of net energy expressed in terms of NEF (Nettoenergie-Fett, Schwein) has been calculated according to the Rostock-System, {Nehring, Beyer & Hoffmann (1970), Futtermittel-Tabellenwerk). From these tables (p.
318-332) the following values for NEF kcal per kg dry matter have been taken:
Barley Maize Sorghum
Skim-milk powder Soyabean meal Meatbone meal
Protein mixture, calculated
2448
Table 17. Daily intake of feed and energy in the experiments "with maize. Series C-F.
Mean of 6 pigs in each group
Tabel 17. Daglig optagelse af foder og energi i forsøgene med majs. Serie C-F.
Middel af 6 svin i hver gruppe
Period
Maize and skim-milk powder Live
Daily intake of Feed
Maize and
Feed
protein mixture Daily intake of
ME
*) Calculated from Nehring et al. Futtermitteltabellenwerk. (1970)
Table 18. Daily intake of feed and energy in the experiments with sorghum. Series D-F.
Mean of 6 pigs in each group
Tabel 18. Daglig optagelse af foder og energi i forsøgene med milo. Serie D-F.
Middel af 6 svin i hver gruppe
Period Sorghum and skim-milk powder Sorghum and protein mixture Live Daily intake of Live Daily intake of weight weight
Feed ME NEF*) no. kg kg Meal Meal
I 24.0 0.80 2.81 1.92 II 29.0 1.00 3.54 2.38 III 35.3 1.19 4.21 2.84 IV 43.0 1.47 5.16 3.48 V 50.6 1.75 6.14 4.10 VI 60.1 2.03 7.15 4.75 VII 70.6 2.31 8.09 5.38 VIII 80.4 2.60 9.05 6.02
*) Calculated from Nehring et al. Futtermitteltabellenwerk. (1970)
kg
The average daily intake of feed in relation to liveweight is demonstrated graphically in Figure 11. Calculated according to the Scandinavian Feed Unit System, the pigs in Series C-D-E-F with a mean live weight of 23 kg in period I received on average 0.90 Sc.f.u., ending with 2.85 Sc.f.u. at a live weight of about 80 kg.
kg
25
f feed ODaily intake ol
1,0
0,5
-i
• BA+MlorPR T MA+MlorPR A SO+MI or PR
/
i i i
A
i i i
20 30 40 50 60
Live weight
70 80 kg
Figure 11.
Daily intake of feed in relation to live weight.
Daglig optagelse afforsøgsfoder i relation til legemsvægt.
In the studies ofOslage, Fliegel, Farries & Richter (1966) concerning prot-ein-and fat gain in growing pigs it was stated, that the animals were fed to a maximum level which would ensure no feed residue. In the live weight group from 20-30 kg the pigs were able to eat 1.1 kg of a diet consisting of 70% barley and 30% protein mixture, being about 30% above the norm used in our investigation. At 80-90 kg the norm was of the same magnitude 2.70 kg in both investigations.
In the present investigation, the mean values for daily intake of metabol-izable energy for the six rations in question (Tables 16, 17, 18) are plotted against the corresponding live weight, and the mean curve is demonstrated in Figure 12. For comparison, curves indicating the intake of metabolizable energy used by other authers in their trials concerning energy metabolism in growing pigs, are shown.
Meal 9,0 8,0
70
ÜJ
4,0 3,0 2,0
Present invest.
Nielsen (1970) Breirem (1935)
20 30 40 50 60 70 80 90 kg Live weight
Figure 12.
Daily intake of metabolizable energy (ME) in relation to live weight.
Daglig optagelse af omsættelig energi (ME) i relation til legemsvægt.
The curve from the trials of Nielsen (1970), including 56 pigs receiving no screenings from U.S.5 barley in their rations, indicates at 20 kg live weight the same norm of about 2.0 Meal ME as in our investigation. The feed curve used by Nielsen increases less rapidly than the curve used by us, thereby the pigs at 85 kg live weight in the experiments of Nielsen received 8.2 Meal ME, being 0.7 Meal ME less than in our experiments.
From the trial of Breirem (1935), 5 pigs on low protein diet and 3 pigs on high protein diet were used for the calculation of intake of metabolizable energy at different live weights. At 20 kg the intake was 2.7 Meal ME being about 0.7 Meal above our norm, while at 85 kg the norm used by Breirem, increasing rather slowly, was only 7.5 Meal ME or 1.4 Meal below the norm used in our experiments.
The norm used by Verstegen (1971) in his experiments with 8 »single pigs in pair«, started with 2.3 Meal ME at 20 kg and from 30 kg of live weight it was closely related to that of Breirem (1935). While all the curves discussed are of the same types, the curve from the trial oiOslage et al. (1966) is quite other-wise, being more S-shaped. No explanation can be found, but perhaps it is
related to the fact that the respiration trial started with 4 pigs, but one pig became ill and died during the experimental time.
The use of digestible energy (DE) instead of metabolizable energy (ME) to express the energy values of rations for pigs is frequently discussed. In A.A.C.
(1967) it is stated »that pigs are usually given well balanced diets in which urinary losses are reasonably constant, then variations in the ratio ME:DE should be small, and hence it could be equally satisfactory to use the more easily determined DE values«.
In the present investigation, where we have tried to keep the intake of protein close to the requirement, a problem which will be discussed in the next section, the energy loss in urine has been constant and rather low. The constancy of the ratio ME:DE during the experimental time, independent of the 6 ration in question, is demonstrated in Figure 13.
A regression of ME on DE is calculated from the individual figures in the main tables and the results are shown in Table 19. For all rations in question the metabolizable energy was found to be 97.2% of the digestible energy, or an
Meal 9,0 8,0 70
o
Ï5P
3,0 2,0
BA*Ml or PR MA+MI or PR SO + MI orPR
2.0 3,0 40 5,0 6,0 7,0 Daily intake of DE
8,0 9,0 Meal Figure 13.
Metabolizable energy (ME) in relation to digestible energy (DE). Mean of 6 different rations measured in 8 balance periods.
Omsættelig energi (ME) i relation til fordøjelig energi (DE). Middelvær-dier for 6 fodertyper målt i 8 balance-perioder.
Table 19. Regression of metabolizable energy on digestible energy. Series C-D-E-F Tabel 19. Regression af omsættelig energi på fordøjelig energi. Serie C-D-E-F
Barley
» Maize
» Sorghum
» Total
+ Skim-milk powder, + Protein mixture, + Skim-milk powder, + Protein mixture, + Skim-milk powder, + Protein mixture,
BA -BA H MA H MA H SO H SO H
h MI - PR h MI h PR h MI - PR
n 94 96 48 48 47 48 381
Regression-coefficients
0.974 0.970 0.973 0.968 0.975 0.972 0.972
sb 0.00037 0.00044 0.00057 0.00057 0.00074 0.00068 0.00024
urinary loss of energy of 2.8% which is considered to be low. The slightly higher energy loss i urine, found by feeding compounds containing protein mixture as compared with milk compounds, could be explained by the somewhat higher intake of protein, (cf. section 4.3.).
In the experiments with low and high protein level Breirem (1935) found an energy loss in urine from 2.2% to 4.0% of the gross energy, the same values as found by Verstegen (1971). In the trials of Nielsen (1970) with 6 different types of grain combined with different amounts of protein mixture the loss of energy in the urine varied from 2.6-4.1% in the first balance period and from 3.6-4.6%
in the last period. In the experiments with adult pigs fed different rations performed at the Oskar Kellner Institute, the energy loss in urine was found to be on average 4.9% of the DE, with a range of variations from 3.5-6.4%, Schiemann, Nehring, Hoffmann, Jentsch & Chudy (1971). In their difference experiments with concentrates, the energy loss in urine was on average 8.3% of DE, ranging from 2.6-15.9% caused by the rather high intake of protein from the concentrates.
The intake of net energy (NEF) has been calculated as described earlier and the figures are shown in Tables 16, 17, 18. The relation between the calculated intake of net energy and the determined intake of metabolizable energy in the different rations used in the present investigation is shown graphically in Figure 14. The graph indicates that in the present investigation there was a close proportionality between the calculated net energy and the metabolizable ener-gy determined for the 6 different rations consisting of barley, maize or sorghum in combination with skim-milk powder or protein mixture, irrespective of the increasing amount of grain in the feed compounds during the experimental time.
From the individual figures a regression of NEF on ME is calculated and the results are shown in Table 20. For all rations in question the ratio of NEF to ME
Meal 6,0
.S '
2 3,0
2,0 1,0 _
-_
-i
• BA+MlorPR T MA+MlorPR A SOMIor PR
I 1 1 1 1 1 1
2,0 3,0 4,0 5,0 6,0 7,0 8,0 9,0 Meal Daily intake of ME
Figure 14.
Net energy (NE, calculated) in relation to metabolizable energy (ME, determined). Mean of 6 different rations measured in 8 balance periods.
Netto energi (NE, beregnet) i relation til omsættelig energi (ME, be-stemt) . Middelværdier for 6 fodertyper målt i 8 balance-perioder.
was 67.3% differing from 66.0% for the compound of sorghum + protein mixture to 68.8% for the maize + skim-milk or protein mixture compounds.
The commonly used feed compounds for growing-fattening pigs consist mostly of 70-80% grain products, with 15-25% protein supply of different origin. In well balanced diets for pigs it can be expected that for practical feeding the feed value can be expressed with the same validity in terms Table 20. Regression of net energy (calculated) on metabolizable energy (determined).
Series C-D-E-F
Tabel 20. Regression af netto energi (beregnet) på omsættelig energi (målt).
Serie C-D-E-F
Barley
» Maize
» Sorghum
» Total
+ Skim-milk powder, + Protein mixture, + Skim-milk powder, + Protein mixture, + Skim-milk powder, + Protein mixture,
BA BA MA MA SO SO
+ MI + PR + MI + PR + MI + PR
n
94 96 48 48 47 48 381
Regression-coefficients
0.672 0.668 0.688 0.688 0.666 0.660 0.673
sb
0.0031 0.0031 0.0043 0.0041 0.0047 0.0052 0.0017
of digestible energy (DE), metabolizable energy (ME) or net energy (NEF).
The multilateral problem concerning preference for one term or another will not be discussed here, as it has not been the aim of the present investigation.