Protocols for fixed-time artificial insemination (FTAI) in swine reproduction can help increase genetic improvement and production efficiency. Different gonadotropin-releasing hormone (GnRH) agonists have been developed to gain better control of follicular development, timing, and ovulation quality; therefore, they have been extensively used in FTAI protocols. This literature review resumes the most important characteristics of the physiology of follicular development and ovulation in sows, followed by a discussion about the hormonal alternatives available to induce ovulation (human chorionic gonadotropin, hCG; porcine luteinizing hormone, LH and GnRH agonists). Also, ovulation induction failures with GnRH agonists are described. Finally, current FTAI protocols with GnRH agonists are resumed and discussed. FTAI with GnRH agonists has proven to be an efficient, successful reproductive protocol that can be implemented in pig farms due to better knowledge of an endocrine system that regulates follicular development and ovulation and increased availability of several GnRH agonists that allow more efficient reproductive swine programs.
Sows were fed naturally contaminated diets containing: (i) 100 ppb zearalenone (ZEN) one week before farrowing and during the lactation period (at 26 days), (ii) 100 ppb ZEN one week before farrowing and 300 ppb ZEN during the lactation period, or (iii) 300 ppb ZEN one week before farrowing and during the lactation period. All diets contained 250 ppb deoxynivalenol (DON). The highest levels of ZEN, α-ZEL, or β-ZEL were observed in the serum of sows fed 300 ppb ZEN before farrowing and during lactation. However, only α-ZEL was significantly increased in the colostrum and milk of these sows. Sows fed the 300 ppb ZEN during the complete trial presented a significant decrease in backfat thickness before farrowing. This effect was accompanied by a decrease in serum leptin levels. These sows also presented a decrease in estradiol levels and this effect was observed in their piglets exposed during lactation, which presented increased glucagon-like peptide 1, but no changes in serum levels of ZEN, α-ZEL, or β-ZEL. Although all sows were fed the same levels of DON, the serum levels of DON and de-epoxy-DON were increased only in the serum of piglets from the sows fed a diet with the highest ZEN levels during the whole experimental period. Moreover, these piglets presented gut inflammation, as indicated by significantly increased calprotectin levels in their serum.
1生猪生产情况 1.1世界猪肉产量小幅度上升 2022年,世界生猪存栏量为78421.4万头,同比上升4.62％.存栏量排名世界前三的国家(地区)分别是中国、欧盟和美国,占世界总存栏量的比重分别为57.28％、18.06％、9.50％.预计2023年世界生猪存栏总量较小幅度回升.如图1.
1 试验背景 母猪批次化生产是根据养猪场产房、配种妊娠栏舍、种源基础及技术和人力等资源条件按批次进行母猪分群,按计划补充后备母猪,并利用生物技术,达到同期发情、同时排卵、同时配种和同期分娩的目的,是一种提高猪场母猪群繁殖性能的高效管理体系.
0 引言 我国是猪肉生产与消费大国.据统计,2022 年全球生猪存栏78421.4 万头,其中,中国生猪存栏 45256.0 万头,占比近 58％;全球猪肉总产量 10984.6 万t,排名前三的中国、欧盟、美国占比分别为 46.43％、20.64％、11.22％.在中国肉类食品消费中,猪肉产品约占 60％,生猪产业对于我国畜牧业和农村经济发展具有举足轻重的作用和重要意义.我国虽是养猪大国,但不是养猪强国.近年来非洲猪瘟疫情对生猪养殖的冲击,凸显我国生猪产业的特点和不足,给予从业者更多的思考与感受.
