Agricultural Institute, BG-9700 Shumen, Bulgaria
NEDEVA, R., 2002. Influence of the different ratio of calcium and phosphorus in the compound feeds on the productivity of growing and finishing pigs. Bulg. J. Agr. Sci., 8: 261–268
An experiment was carried out at the Agricultural Institute, Shumen, with three groups, having totally 42 pigs from weaning at 7.0–7.2 kg (at 38-day of age) to 110 kg liveweight. The digestibility coefficients of the basic nutrients of 3 pigs from I and III groups (totally 6 pigs with liveweight 60–70 kg) were determined. It was established that the increase of calcium from 0.70–0.60% to 1.20–1.00 and to 1.50–1.25% (at constant level of phosphorus 0.60–0.50%) and the increase of the ratio between calcium and phosphorus from 1.2:1 to 2.5:1 in the feeds of four-bred pigs (DWxCH) and (BLxLW) from weaning at 7.1 kg to 31–35 kg negatively affected the growth rate, the consumption and the feed conversion. The increase of calcium from 0.60–0.50% to 1.00–0.80 and to 1.25–1.00% (at constant level of phosphorus 0.50–0.40%) at ratio between calcium and phosphorus from 1.2:1 to 2.5:1 from 31–35 kg to 110 kg negatively affected the growth rate and the feed conversion. The correlation coefficients between the calcium intake, the average daily gain (rp = –0.574) and the feed conversion (rp = 0.551) for the whole experimental period outline unfavourable influence of the increased levels of calcium in the feeds on the growth rate and the feed conversion.
The digestibility coefficients of the separate nutrients (dry and organic matter, crude protein, crude fat and NFES) in the animals from the two groups do not differ considerably. The digestibility coefficient of crude fiber is significantly lower in pigs which consumed higher level of calcium and increased Ca/P ratio.
The different levels of calcium did not influence considerably the indices of the slaughter analysis at the end of fattening.