| Abstrakt: |
Sixty-four crossbred gilts were randomly assigned postbreeding to one of four dietary regimes for three successive parities. Gestation diets (1.82 kg/day) were: (1) 14% protein sorghum-soybean meal (S-SBM), (2) 12% protein S-SBM, (3) fortified sorghum to day 80, then 12% S-SBM until farrowing and (4) as diet 2 except the protein source was V4 SBM-Vi cottonseed meal, direct solvent processed (S-SBM-CSM). Sows were fed ad libitumduring 35-day lactations; treatments 1, 2 and 3 received 16% protein S-SBM diets and treatment 4 a 16% S-SBM-CSM diet. An 18% protein creep diet was available for the nursing pigs after 10 days of age. Three growing-finishing trials determined the effect of gestation dietary protein level and source on the performance and carcass merit of selected progeny (total of 208 pigs).No significant differences (P<.05) were found among treatments in live pigs farrowed or weaned/litter, creep diet intake/litter, lactation intake/sow, lactation weight change or farrowing interval.Gestation weight gain was higher (P<.05) for females fed diets 1 and 2 than those fed diets 3 and 4. Live pig birth weights were heavier (P<.05) for treatments 1 and 3 than treatment 4. Weaning weights for pigs fed the S-SBM-CSM gestation and lactation diets were lower (P<.05) than those from females fed the SBM-supplemented diets.No significant treatment differences were found in pig performance or in composition of the longissimusmuscle among the progeny. However, pigs from females fed 218 g protein daily throughout gestation (treatments 2 and 4) had more backfat depth (P<.05) at market weight than pigs in the other two treatments. Pigs from treatments 3 and 4 were slightly older at 91 kg, tended to be less efficient and had slightly higher ether extract values than pigs from treatments 1 and 2.The 14%, 12% and fortified sorghum to day 80 gestation diets appear adequate for optimum reproductive performance when sows are fed a 16% protein S-SBM lactation diet ad libitum. The gestation treatments used apparently had no adverse effect on the ontogeny of the offspring from weaning to market weight (97 kg). |
