PSA-Environment and Management-Breeder and Incubation

Nicholas, BUTA-B6 and BUTA-T2 strains (A, B, and C) were reared in a total of 24 floor pens (0.309m2/bird) and fed commercial diets until 19 wk of age. The basal feeding program (calculated analysis) included a pre-starter (0-3 wk; 28.3% CP; 1.51% Ca; 1.04% tP), starter (3-6 wk; 27.8% CP; 1.50% Ca; 1.03% tP), grower-I (6-9 wk; 24.5% CP; 1.48% Ca; 1.00% tP), grower-II (9-11 wk; 22.5% CP; 1.39% Ca; 0.92% tP), finisher-I (11-14 wk; 18.9% CP; 1.15% Ca; 0.72% tP), and finisher-II (14-19 wk; 17.4% CP; 1.04% Ca; 0.64% tP). From 11-14 wk half the birds were fed a diet 15% lower in Ca and P (LCP) compared to the control birds (CON). From 14 19 wk half the birds were fed a diet 30% lower in Ca and P (LCP) compared to the CON birds. Both diets were supplemented with 0.06 % phytase from 1114 and 14 19 wk. Dietary treatment did not affect feed intake (FI), feed conversion (FC), 19 wk body weight (BW) or overall mortality. BW at 14 wks and overall BW gain (BWG) were significantly greater for birds fed CON diets. Dietary treatment did not affect processing weight (wt) or wt as a percent of the bled carcass wt. However, LCP diets did result in significant feed savings on a /kgcarcass(CON,.431 versus LCP, .419)and/kg breast basis (Con, 1.857versusLCP,1.749). BW at hatch and wk 3, 6, 9, 11, 14, and 19 were significantly affected by strain, with the C strain males having greater BWG than males from strain A or B. Cumulative FI was significantly different, with the C strain birds consuming more feed than birds from either strain A or B. Overall FC and mortality were not affected by strain. Processing wt was significantly affected by strain, with the wt of the carcass, neck, wing, and breast being greater for C strain carcasses. No difference in processing yield (% of carcass wt) was found for strain. The results suggest that diets 15 and 30% lower in Ca and total P, supplemented with phytase, resulted in similar growth performance and carcass yield and were cost efficient in comparison to CON fed birds. Strain C males were significantly heavier than strain A and B males for much of the study.