Reproductive performance of sows fed elevated calcium and phosphorus levels during growth and development

A cooperative regional study (S-145) involving 586 farrowings was conducted at five state experiment stations (Georgia, Mississippi, South Carolina, Tennessee and Virginia) to determine the influence of feeding elevated Ca and P levels during growth and development on general reproductive efficiency and longevity of confined, housed females kept for three consecutive parities. Two dietary Ca and P levels (100 vs 150% of 1979 NRC-recommended amounts) were fed ad libitum from weaning to 100 kg. A diet containing .8% Ca and .6% P was limit-fed to all gilts and to all sows during gestation and lactation. Growth rate and feed efficiency from weaning to 100 kg were similar (P greater than .10) for gilts fed 100 vs 150% Ca and P levels. A similar total number of litters (292 vs 294) was farrowed by each previous treatment group. From the previously-fed-100% Ca and P group, 78 and 65% of the sows that completed the first parity completed the second and third farrowing, respectively. Similarly, from the previously-fed-150% Ca and P group, 81 and 57% completed the second and third farrowing, respectively. Across all locations, total pigs born, live pigs born, stillborns, birth weight, number and weight of pigs at 21 d of age, sow weight at 110 d of gestation and at weaning did not differ (P greater than .10) between the two previously fed sow groups. There were significant location and farrowing effects, but most two-way interactions with Ca and P levels were not significant.