EFFECT OF BULKY DIETS BASED ON WHEAT BRAN OR OAT HULLS ON REPRODUCTIVE-PERFORMANCE OF SOWS DURING THEIR FIRST 2 PARITIES

The aim of the present study was to determine the effect of different degrees of bulkiness in the gestation diet on reproductive performance of sows during their first two parities. The density of the diets was modified by incorporating a high proportion of fibrous ingredients (w heat bran and corn cobs in Diet 2 and oat hulls and oats in Diet 3). A diet without fibrous ingredients was used as a control (corn and soyb ean meal in Diet 1). Although all the gestation diets were formulated to provide the same daily intake of the major nutrients, sows fed Diet 3 were the lightest and had the lowest backfat thickness (P less than or equal to .05) during both parities, and those fed Diet 2 were the heaviest and the fattest (P less than or equal to .05) during the seco nd parity. These results seem to indicate an overestimation of the cal culated nutritive value of Diet 3, whereas those obtained with Diet 2 seemed to be linked td its marked effect on behavior of sows during th e second parity. There was no marked effect (P > .11) of treatments on the number of pigs born alive, on preweaning mortality, or on the wea ning-to-estrus interval. At parturition, total litter weight was simil ar among treatments in the first parity, whereas in the second parity it was greater(P less than or equal to .05) in sows fed Diet 2 than in those fed Diets 1 and 3. In both parities, feed intake of the common lactation diet given during lactation was 5% higher (P less than or eq ual to .05) for sows fed Diet 3 during gestation than for sows fed the other diets. In the first parity, no treatment effect (P greater than or equal to .25) was observed on total litter weight from 3 d to 8 wk of age, whereas in the second parity it was approximately 20% higher (P less than or equal to .01) for sows on Treatment 2 than for those o n the two other treatments. Therefore, the use of bulky diets during g estation of sows can have beneficial effects on postnatal growth of pi gs if the digestibility and the metabolic availability of the nutrient s from the fibrous feeds are well known.