Resumo -O desempenho reprodutivo de fêmeas suínas foi avaliado com o objetivo de comparar duas técnicas de inseminação. Foram inseminadas, em delineamento inteiramente casualizado, 608 fêmeas com ordem de parto de dois a quatro, em dois tratamentos: inseminação intra-uterina com 1,5 bilhão de espermatozóides em 60 mL e inseminação tradicional, com 3 bilhões em 90 mL. Foi possível introduzir o cateter intra-uterino em 97,4% das fêmeas e houve sangramento em 9,5%, as quais apresentaram retorno ao estro superior (p<0,05). O porcentual de volume refluído até duas horas após a inseminação foi maior (p<0,05) na inseminação intra-uterina do que na tradicional, enquanto o porcentual de espermatozóides refluídos foi semelhante. Não houve influência do porcentual de espermatozóides refluídos sobre a taxa de parto e tamanho da leitegada. Não houve diferença nas taxas de retorno ao estro (3,6% e 4,3%), de prenhez aos 21 dias (99,5% e 97,2%), de parto ajustada (94,9% e 94,3%) e tamanho da leitegada (11,6 e 11,8 leitões) entre os dois tratamentos, respectivamente. A inseminação intrauterina permite a obtenção de desempenho reprodutivo semelhante ao observado na tradicional, porém com uso de menor número de espermatozóides.Termos para indexação: número de espermatozóides, parto, refluxo de sêmen, reprodução, tamanho da leitegada, taxa de prenhez. Reproductive performance of swine females inseminated by intrauterine or traditional techniqueAbstract -The reproductive performance of sows was evaluated aiming at the comparison of two insemination techniques. In a completely randomized design, 608 females of 2-4 parities were inseminated in two treatments: intrauterine with 1.5x10 9 spermatozoa/60 mL or traditional insemination with 3x10 9 spermatozoa/90 mL. It was possible to insert the intrauterine catheter in 97.4% of females and bleeding was observed in 9.5%, which had a higher probability to repeat estrus (p<0.05). The percentage of semen backflow volume, during two hours after insemination, was significantly higher (p<0.05) in intrauterine insemination than traditional, whereas sperm backflow percentage was similar. The sperm backflow percentage did not influence the farrowing rate and the litter size. There was no difference in the return to estrus rate (3.6%; 4.3%), pregnancy rate at 21 days postinsemination (99.5%; 97.2%), adjusted farrowing rate (94.9%; 94.3%) and average litter size (11.6; 11.8 piglets) between treatments, respectively. The intrauterine insemination ensures a reproductive performance similar to traditional, but with a lower sperm number.

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RESUMO O objetivo deste trabalho foi avaliar o desempenho reprodutivo de 423 fêmeas suínas de ordem de parto 1 a 9 submetidas à inseminação intra-uterina (IAU), com um novo modelo de pipeta (T1) cuja extremidade não é fixada na cérvix ou uma pipeta de IAU modelo Verona RO (8.0% and 4.8%), PR (93.4% and 96.2%) and TLS (12.4 and 12.7 piglets) between T1 and T2 groups, respectively. AFR of T1 (90.6%)

Hypothermic storage of boar semen provides the possibility to omit antibiotics from semen extenders so long as sperm quality is maintained and bacterial growth prevented. The objective of this study was to determine an optimal cooling-rate frame for boar semen preserved at 5˚C in an antibiotic-free extender. Semen from eight boars extended in AndroStar ® Premium was cooled from 30˚C to 5˚C using seven different cooling rates, ranging initially from 0.01 to 0.36˚C min-1 and reaching 5˚C between 2 h and 24 h after dilution. Sperm motility, membrane integrity, membrane fluidity, mitochondrial membrane potential and the response to the capacitation stimulus bicarbonate remained at a high level for 144 h at 5˚C when the semen was initially cooled in a cooling-rate frame ranging from 0.01 to 0.09˚C min-1 in the temperature zone from 30 to 25˚C, followed by 0.02 to 0.06˚C min-1 to 10˚C and 0.01 to 0.02˚C min-1 to the final storage temperature. A cooling rate of 0.07˚C min-1 in the temperature zone from 30 to 10˚C led to a reduced response to bicarbonate (P < 0.01) and fast cooling to 5˚C within 1 h with a cooling rate of 0.31˚C min-1 resulted in lower values (P > 0.05) of all sperm parameters. In a further experiment, slow cooling with a holding time of 6 h at 22˚C induced after 6 h storage a temporary increase in Escherichia coli of 0.5 × 10 3 to 2.4 × 10 3 CFU mL-1 in the sperm-free inoculated extender. Overall, the load of mesophilic bacteria in the stored semen was below 6 × 10 3 CFU mL-1 , a level that is not regarded as critical for sperm quality. In conclusion, appropriate cooling protocols were established for the antibiotic-free storage of boar semen at 5˚C, allowing the application of hypothermic preservation in research and in artificial insemination.

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.