SOLVENT-EXTRACTED RAPESEED MEAL AS A REPLACEMENT FOR SOYBEAN MEAL IN DIETS FOR SWINE REPRODUCTION

At an average weight of 83 kg and age of 163 days, 32 gilts were allotted to four dietary treatments, 0, 4 or 8% solvent-extracted rapeseed meal (RM) throughout the experiment, or 8% RM fed for the first 100 days of gestation followed by 0% RM. The RM, of Brassica campestris origin and containing 2.40 g oxazolidinethione and 2.60 g isothiocyanates per kg meal, was added in substitution for isonitrogenous levels of soybean meal (SM) for two reproductive cycles. Feeding RM did not significantly influence daily gain or feed conversion efficiency from 83 kg to the first breeding or during the two gestation periods. No significant differences were noted in number of services to conception, length of gestation, number of pigs born or born alive, number of pigs weaned, litter birth weights or weaning weight, or pig birth weights or weaning weights. There was a trend toward reduced litter size from gilts and sows fed the diets containing RM. Changing the diet from 8% RM to 0% RM after 100 days of gestation did not influence reproductive performance. Lacombe × Yorkshire sows gained more from 83 kg live weight to the first breeding, had higher breeding weight in both gestation periods, and increased pig weaning weight for the second lactation period compared with Yorkshire sows. The latter sows had higher individual pig birth weights for the first reproductive cycle than the crossbred sows. The results indicate that a level of 8% commercial solvent-extracted RM of the type fed may be acceptable as a substitute for an isonitrogenous level of SM in the diets of gestating and lactating gilts and sows. </jats:p

COMPARATIVE EVALUATION OF SOME TECHNIQUES USED IN DETERMINATIONS OF NITROGEN AND ENERGY CONTENT OF FECES FROM PIGS

Statistical procedures were used to compare some techniques used in digestibility studies with pigs. No significant differences were observed in fecal nitrogen (N) content when measured in the wet or dry (dried at 60 C for 72 hours) form, or in fecal energy when measured in the wet or dry form. There was, however, an average 3.7% N loss and 5.0% caloric loss from dry feces compared with wet feces. When dry fecal material was subjected to 1, 2, 3 or 4 hours of digestion after the sample became clear using the Kjeldahl method, no significant difference was observed between the length of digestion time and the percent N obtained. It may be concluded that either wet or dry pig fecal material may be used for N and energy determinations in pig digestion trials, without significantly influencing results obtained. Digestion time of dry fecal material, within the limits studied, did not alter N content as determined in the feces. </jats:p

DIGESTIBLE AND METABOLIZABLE ENERGY VALUES FOR RAPESEED MEALS AND FOR SOYBEAN MEAL FED TO GROWING PIGS

Twelve samples of rapeseed meal (RM) and one sample of soybean meal (50% protein) (SM) were evaluated for digestible energy (DE), metabolizable energy (ME), nitrogen-corrected ME (MEn) and digestible nitrogen (DN). RM samples were of Brassica campestris and B. napus origin and contained meals processed by solvent, prepress-solvent or expeller processes. Two of the meals were from rapeseeds not in commercial production, one a Bronowski (low glucosinolate) napus meal and one a meal from zero-erucic acid rapeseed of napus type. Energy studies were conducted with 64 pigs at 16, 33 and 65 kg liveweight, adding 25% by weight of the test ingredient to the total diet. The overall means and standard errors for all weight groups for gross energy (GE), DE, ME and MEn, in kcal/g of dry matter, for 10 RM (excluding Bronowski and zero-erucic acid RM) were 4.74 ± 0.12, 3.21 ± 0.18, 2.89 ± 0.19 and 2.64 ± 0.19, respectively, while the values obtained for SM were 4.81 ± 0.08, 4.21 ± 0.16, 3.92 ± 0.17 and 3.64 ± 0.16. There were no significant differences in DE, ME or MEn among the 12 RM samples, or between weight periods. The values for the basal diet were uniform throughout. The overall mean coefficient for DN was 75.9% for RM and 89.2% for SM. The DE, ME and MEn values for RM should be considered as being species specific. </jats:p

EFFECT OF METHOD OF DETERMINATION ON DIGESTIBLE ENERGY AND NITROGEN AND ON METABOLIZABLE ENERGY VALUES OF RAPESEED MEAL AND SOYBEAN MEALS FED TO GROWING PIGS

Commercial samples of solvent-extracted rapeseed meal (RM), 44% crude protein soybean meal (SM) and 50% crude protein SM were evaluated for digestible energy (DE), metabolizable energy (ME), nitrogen-corrected ME (MEn) and digestible nitrogen (DN), using two methods of evaluation. A comparison of results from feeding the test meals for two different lengths of time prior to conducting the determinations was also made. Sixteen castrate male pigs were allotted to each of the two evaluation methods, with four pigs assigned to each of three treatment groups, and four pigs assigned to the basal control group for each method. The two SM samples had higher DE, ME, MEn and DN than the RM sample. The DE, ME and MEn values in kcal/g dry matter for RM were 3.37, 3.13 and 2.76, and for SM they we’re 4.42, 4.21 and 3.71, respectively. The overall mean coefficient for DN was 79.2% for RM and 92.8% for SM. There were no significant differences observed between methods or between the two time periods. The values for the basal diets were uniform throughout the trial, as indicated by low standard errors. </jats:p