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The effects of increasing feed intake (1.8, 2.3, 2.8, and 3.3 kg/d) during late gestation of gilts on piglet birth weight and female reproductive performance were evaluated. A total of 977 gilts were fed a diet based on corn-soybean meal (3.29 Mcal ME per kg and 0.64% standardized ileal digestible lysine) from day 90 of gestation until farrowing. Gilts were weighed on days 90 and 112 of gestation, at farrowing and weaning. Born alive and stillborn piglets were weighed within 12 h of birth. Colostrum yield (CY), lactation feed intake, and litter growth rate were measured in a randomly selected subsample of 245 gilts. The data were analyzed using generalized linear mixed models. As expected, gains in body weight (BW) were different at day 112 (P < 0.001) with the greatest values observed in the 3.3 kg/d treatment. As feed intake increased during late gestation, BW, body condition score (BCS), backfat (BF), and Caliper unit also increased between day 112 and weaning (P < 0.001). No differences were found among treatments in total number of piglets born, mummified fetuses, sum of born alive and stillborn piglets, and within-litter birth weight CV (P > 0.05). Tendencies for quadratic effect of feed intake were observed for born alive piglets (P = 0.079), average birth weight of piglets (P = 0.083), and litter weight (P = 0.059). Gilts with lower feed intake during late gestation had reduced percentages of stillborn piglets than gilts with greater feed intakes. The CY decreased linearly (P < 0.05) as the feed intake was increased. No differences among treatments were found at weaning in individual piglet weight and litter weight, as well as in percentage of weaned piglets (P > 0.05). Lactation feed intake decreased as gestation feeding level increased (P < 0.05). No differences in the subsequent cycle were observed among treatments for farrowing rate, retention rate up to the next farrowing, number of total piglets born, born alive, stillborn piglets, and mummified fetuses (P > 0.05). In conclusion, increased feed intake from day 90 of gestation until farrowing resulted in increased maternal BW gain and stillborn rate, but reduced CY and lactation feed intake. A slight increase in birth weight was observed for the 2.3 kg/d treatment. Furthermore, litter growth and subsequent female reproductive performance were not affected by feed intake during late gestation.

The increase in the litter size in past decades has caused reduction in the individual piglet birth weight. Therefore, nutritional strategies employed in the last third of gestation in order to improve the piglet birth weight have been studied. This study aimed to evaluate the effects of 2 different feeding levels (1.8 and 2.2 kg/d) in the last third of gestation on the piglet birth weight and the female reproductive performance. A total of 407 females were fed on a diet based on corn-soybean meal (3.25 Mcal ME per kg and 0.65% standardized ileal digestible lysine) from day 90 of gestation until farrowing. The females were weighed on day 90 and day 112 of gestation, and at weaning. Born alive and stillborn piglets were weighed within 12 h of birth. The lactation feed intake and the litter growth rate were measured in a randomly selected subsample of 53 sows from each treatment. The data were analyzed using the generalized linear mixed models, considering the females as the experimental unit. Parity, treatment, and their interaction were analyzed for all responses. The females fed on 2.2 kg/d of diet from day 90 to day 112 exhibited greater body weight gain compared to the females fed on 1.8 kg/d (P <0.001). No evidence of the effects of feeding levels on the individual piglet birth weight and on the within-litter CV were observed, for both gilts and sows (P ≥0.90). Similarly, when the classes of the total born piglets were considered in the analysis (<15 and ≥15 for gilts; <16 and ≥16 for sows), no positive effects of increasing the feeding level were observed on the individual piglet birth weight and the within-litter CV (P ≥0.47). Also, no differences in the stillborn rate, mummified-fetus rate, and percentage of piglets weighing less than 1,000 g at birth were observed between the treatments (P ≥0.28). The females fed on 1.8 kg/d of diet exhibited greater feed intake during lactation, compared to the females fed on 2.2 kg/d (P <0.05). Weaning weight, weaning-to-estrus interval, subsequent litter size, and culling rate were not affected by the dietary levels (P ≥0.23). In conclusion, increasing the feed intake from day 90 of gestation until farrowing increased the body weight gain in sow, demonstrated no effect on the piglet birth weight, and reduced the lactation feed intake. Furthermore, there was no evidence of the effects of the treatments on the litter growth rate or on the subsequent female reproductive performance.

Our objective was to evaluate the effects of dietary fiber supplementation in late gestation on farrowing characteristics and sow and piglet’s performance. On d 105 of gestation, a total of 420 sows were selected according to body condition score, caliper units and parity (0 to 6), and randomly assigned to one of two treatments in a completely randomized design. Treatments included 1) Low fiber diet (LF) with 2.02% crude fiber; and 2) High fiber diet (HF) with 5.12% crude fiber. The LF diet was based on corn and soybean meal with 3.26 Mcal of ME/kg and 0.60% SID Lys. The HF diet was corn-soybean meal-based with 10% soy hulls, containing 3.13 Mcal/kg and 0.60% SID Lys. Sows in both treatments were fed 1.8 kg/d. Fecal score was daily evaluated until farrowing. Farrowing duration and birth weight of born alive and stillborn piglets were recorded. The farrowing was manually assisted when the birth interval was longer than 30 min. Data were analyzed by the GLIMMIX procedure of SAS, and comparisons were performed with Student’s t-test at 5% of significance. Sows fed HF diet had fewer days with dry feces compared to those fed LF diet (P = 0.008). No evidence for treatment effects were observed on farrowing duration (P = 0.25) and farrowing assistance (P = 0.09). Sows fed HF diet had greater number of total piglets born (P = 0.01), but there was no evidence (P > 0.05) for treatment differences on the percentage of piglets born alive, stillborn piglets, or mummified fetuses. Piglets from sows fed LF diet had a greater birth weight than those from sows fed HF diet (P = 0.04). No evidence for differences were observed between treatments for pre-weaning mortality, number and weight of weaned pigs (P > 0.05). In conclusion, the HF diet did not show positive effects on farrowing duration, farrowing assistance, and sow and piglet performance.

The effects of increasing weaning age in a commercial production system on nursery and finishing performance were evaluated. A total of 1,176 pigs (PIC 337 × Camborough) were used in a 136-d growth trial with 14 and 10 replications/weaning age on the nursery and finishing phases, respectively. Treatments included weaning litters at 19, 22, 25, or 28 d of age. In the nursery, as weaning age increased, initial (5.04, 5.70, 6.52, and 7.26 kg) and final body weight (BW) (18.2, 19.8, 23.0, and 25.1 kg) increased (linear, P < 0.001). Increasing the weaning age reduced (linear, P < 0.001) the prevalence of pigs exhibiting belly nosing (27.6%, 15.0%, 6.5%, and 1.4%) during the first 3 wk. The percentage of pigs losing weight during the first week after weaning (35.1%, 28.7%, 12.4%, and 9.2%) decreased (linear, P < 0.001) as weaning age increased. Average daily gain (ADG; 295, 320, 374, 406 g/d) and average daily feed intake (493, 534, 619, 661 g/d) increased (linear, P < 0.001), while feed efficiency (G:F) (596, 599, 604, and 615) tended to increase (linear, P = 0.081) with weaning age. Removal rate (8.01%, 3.79%, 2.29%, and 1.65%) declined (linear, P = 0.001) as weaning age increased, while there was no evidence of difference (P = 0.463) in mortality rate (0.71%, 0.36%, 0.96%, 1.04%). In the finishing period, BW at 136 d post-weaning (114.9, 117.8, 124.7, and 126.5 kg) and ADG (1.02, 1.04, 1.08, and 1.07 kg/d) improved (linear, P < 0.001). There was no evidence of differences (P > 0.24) in removal (1.5%, 2.4%, 1.0%, and 0.0%) or mortality rates (0.9%, 1.0%, 1.0%, and 1.4%) with changes in weaning age. When performance was analyzed at a common day of life (164 d of age), no effects of weaning age (P > 0.25) were found for BW (125.2, 124.4, 128.0, and 126.5 kg) and lifetime ADG (growth rate from birth to market) (754, 751, 774, and 762 g/d). The BW sold per pig weaned increased (linear, P < 0.001) with weaning age. Even though the slope indicated a linear response, the magnitude of improvement was high until 25 d, before exhibiting diminishing returns from 25 to 28 d. Thus, the study suggests that increasing the weaning age can be an effective strategy to improve the overall performance in a commercial system. Although lifetime performance was not affected by the weaning age range studied, the consistent effect in the nursery and the increment in the number of pigs reaching the market facilitated by the improvement in the removal rate in the nursery phase imply that 25 d is the optimal weaning age.

The effect of increasing the feed level (1.8, 2.5, and 3.2 kg/d) during early gestation in parity 1 (PO1) and parity 2 (PO2) sows on maternal growth and litter size was evaluated. A total of 361 sows were group-housed and fed a diet based on a corn-soybean meal (3.15 Mcal Metabolizable Energy (ME) per kg and 0.68% standardized ileal digestible lysine) from day 6 of gestation until day 30. Sows were weighed at weaning and on day 30 of gestation. Farrowing rate, number of total piglets born, piglets born alive, stillborn piglets, and mummified fetuses were recorded at farrowing. The effect of feed level on the total number of piglets born was also evaluated according to classes of body weight (BW), body condition score (BCS), backfat (BF), and caliper unit at weaning for each parity order. There was no evidence for significant effect of the interaction between feed level × parity on the variables related to maternal growth and reproductive performance (P = 0.128). Greater feed levels linearly increased the gains in body condition (i.e., BW, BCS, BF, and caliper unit) between weaning and day 30 of gestation (P < 0.001). Farrowing rate was not influenced by the feed level (P = 0.200) and parity (P = 0.209). The number of total piglets born decreased linearly as the feed level increased (P = 0.041), whereas no evidences for differences were observed on piglets born alive among treatments (P = 0.317), neither between parities (P = 0.904). For PO1 sows, the total piglets born on BW classes (=183 vs. >183 kg) and on classes of BF (=11.5 vs. > 11.5 mm) were quadratically affected by the feed levels (P = 0.041). In contrast, the number of total piglets born was marginally affected (linear; P = 0.094) by the feed level in the different classes of BW, BCS, and caliper unit in PO2 sows. There was no evidence for differences for the interaction of feed level and classes of body condition (P = 0.199) for PO2 sows. Similarly, no interactions between feed level and classes of BW, BCS, and BF at weaning were observed (P = 0.233) for PO1 sows; however, the total piglets born were affected by an interaction between feed level and caliper unit class (P = 0.042). In conclusion, increased feed intake from day 6 of gestation until day 30 resulted in increased maternal BW gain but reduced the number of total piglets born. Furthermore, lighter and in a poor BCS PO1 sows at weaning produced fewer total born piglets with no benefits from greater amounts of feed.