R. NEDEVA
Agricultural Institute, BG-9700 Shumen, Bulgaria
NEDEVA, R., 2003. Testing the influence of higher levels of calcium and phosphorus on the background of two protein levels in the compound feeds for growing and fattening pigs. Bulg. J. Agric. Sci., 9: 683–692
A production trial was carried out with 40 hybrid pigs (Large White x Landrace) x (Duroc x Belgian Landrace) at the Agricultural Institute – Shumen. The animals were allocated into four groups with 10 pig in each of them. The trial began at weaning at 8.4–8.5 kg live weight and continued to the end of fattening at 100 kg live weight. It was studied the influence of two calcium levels (0.71 – 0.60 – 0.50 % and 1.22 – 1.11 – 1.01 %) and phosphorus (0.60 – 0.50 – 0.40% and 1.04 – 0.93 – 0.80 %) on the background of two protein levels (18.0 – 15.5 – 13.5 % and 16.0 – 13.5 – 11.5 %) in compound feeds, respectively for the periods: from weaning to 30–35 kg, from 30–35 to 55–60 kg and from 60 to 100 kg live weight. It was established that increasing calcium and phosphorus in pigs from weaning to 100 kg live weight did not considerably influence feed intake, growth rate and feed per 1 kg gain. The animals consumed lower protein level had significantly higher feed intake (by 4–5 %, P £ 0.05), insignificantly lower gain and higher feed per 1 kg gain (by 6–8 %, P £ 0.05). The lower protein levels unfavourably influenced carcass composition (meat and bones, %; fat, %). The compound feeds containing protein – 18.0 – 15.5 – 13.5 %, calcium – 0.71 – 0.60 – 0.50 % and phosphorus – 0.60 – 0.50 – 0.40 % for the periods from weaning to 30–35 kg, from 30–35 kg to 55–60 kg and from 60 to 100 kg live weight could be considered suitable for growing and fattening pigs.