Nuevas estrategias en el manejo hormonal de la reproducción en las cerdas nulíparas

95 p.La principal hipótesis de este trabajo es que la falta de respuesta estral en el 30% de cerdas prepúberes tratadas con hormonas exógenas es debida a una inadecuada combinación de las gonadotropinas eCG y hCG para promover el correcto crecimiento folicular y la instauración de la pubertad. Para demostrar esta hipótesis, 6 diferentes experimentos fueron llevados a cabo con el objetivo de comparar las respuestas estral y ovulatoria inducida por la administración de PG600 con los siguientes protocolos hormonales: i. administración de eCG sola, ii. pretratamiento con FSH seguido con eCG, iii. administración de hCG sola, iv. pretratamiento con FSH seguido con hCG, v. tratamiento con eCG seguido de hCG, vi. tratamiento con eCG + hCG seguido de hCG. Los tratamientos i y ii están presentados en los capítulos 3 y 4 de la tesis, respectivamente, los tratamientos iii y iv en el capítulo 5, y los protocolos v y vi se recogen en los capítulos 6, 7 y 8. Finalmente, desarrollamos un último experimento presentado en forma de anexo, donde la fertilidad en respuesta a los diferentes protocolos hormonales fue evaluada en cerdas en anestro estacional, que representan un modelo fisiológico similar a las cerdas prepúbere

Effect of Oxytocin, Cloprostenol or Buserelin in Semen Doses on Sow Fertility

[EN] During the periods January to April, May to August, and September to December in two consecutive years, sows were assigned at breeding to receive semen doses supplemented with 87 µg cloprostenol (PG; n = 158), 5 IU oxytocin (OT; n = 154), 2 µg buserelin (GN; n = 93), or served as non-supplemented controls (CON; n = 605). Sows were inseminated at the detection of estrus, and again 24 h later, but only the first inseminations were supplemented. Compared to CON, only buserelin increased pregnancy and farrowing rates (p ≤ 0.05); there was no effect of a period or a treatment × period interaction. Litter size was larger (p ≤ 0.001) for all seminal additive groups during the first two periods and tended to increase in GN compared to CON (p ≤ 0.1) during the third period, resulting in a tendency (p < 0.1) for a period × treatment interaction. The addition of cloprostenol, oxytocin or buserelin to semen doses at first insemination increases litter size in multiparous sows.SIThis research received no external fundin

The Suinfort® Semen Supplement Counters Seasonal Infertility in Iberian Sows

[EN] Suinfort®, a commercial semen supplement demonstrated to increase fertility and litter size in commercial sows, was tested to improve reproductive performance in Iberian sows. A total of 1430 Iberian sows were artificially inseminated (AI) with semen from Duroc boars and assigned by parity to receive the seminal additive Suinfort® containing 2 IU oxytocin, 5 µg lecirelin, and 2 mM caffeine (SF; n = 1713 AI), or to serve as non-supplemented controls (CON; n = 2625 AI). CON showed a lower fertility comparing to winter for spring (p = 0.001) and summer (p 0.05). Fertility was significantly higher for SF sows during summer (p = 0.025) and autumn (p = 0.004). Total born, live-born, stillborn, and mummified piglets did not differ between CON and SF but were impacted by the season, with total and live-born decreasing in summer compared with autumn (p < 0.001) and winter (p = 0.005). In conclusion, seminal supplementation with Suinfort® improved the fertility of Iberian sows during periods of seasonal infertilitySIThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sector

Effect of Season and Parity on Reproduction Performance of Iberian Sows Bred with Duroc Semen

[EN] The Iberian pig is an autochthonous breed from the Iberian Peninsula highly valued for its meat. The sows are often bred as Iberian × Duroc crossings for increased efficiency. Since sow parity and season affect the reproductive performance, we evaluated two-year records from a commercial farrow-to-finish farm (live, stillborn, and mummified piglets after artificial insemination, AI). A total of 1293 Iberian sows were inseminated with semen from 57 boars (3024 AI). The effects of parity (gilts, 1, 2–4, 5–10, and >10 farrowings) and season were analyzed by linear mixed-effects models (LME). The data were fitted to cosinor models to investigate seasonal effects within parity groups. The effects of maximum daily temperature (MDT) and day length change (DLC) during spermatogenesis, pre-AI, and post-AI periods were analyzed with LME. The 2–4 group was the optimal one for parity. A seasonal effect was evident between spring–summer (lower fertility/prolificacy) and autumn–winter (higher). Cosinor showed that the seasonal drop in reproductive performance occurs earlier in Iberian sows than in other breeds, more evident in gilts. MDT negatively affected performance in all periods and DLC in spermatogenesis and pre-AI. These results are relevant for the improvement of Iberian sows’ intensive farmingSIF. Martínez-Pastor participated in the PIVEV network (AGL2016-81890-REDT, MINECO). This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sector