Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.
Research and Innovation, Rivalea (Australia) Pty. Ltd, Redlands Road, Corowa, New South Wales 2646, Australia.
Animal. 2022 Aug;16(8):100596. doi: 10.1016/j.animal.2022.100596. Epub 2022 Aug 8.
Progeny born to primiparous sows farrowing their first litter, often called gilt progeny (GP), are typically characterised by their poorer overall production performance than progeny from multiparous sows (sow progeny; SP). Gilt progeny consistently grow slower, are born and weaned lighter, and have higher postweaning illness and mortality rates than SP. Collectively, their poorer performance culminates in a long time to reach market weight and, ultimately, reduced revenue. Due to the high replacement rates of sows, the primiparous sow and her progeny represent a large proportion of the herd resulting in a significant loss for the pig industry. While the reasons for poorer performance are complex and multifaceted, they may largely be attributed to the immature age at which gilts are often mated and the significant impact of this on their metabolism during gestation and lactation. As a result, this can have negative consequences on the piglet itself. To improve GP performance, it is crucial to understand the biological basis for differences between GP and SP. The purpose of this review is to summarise published literature investigating differences in growth performance and health status between GP and SP. It also examines the primiparous sow during gestation and lactation and how the young sow must support her own growth while supporting the metabolic demands of her pregnancy and the growth and development of her litter. Finally, the underlying physiology of GP is discussed in terms of growth and development in utero, the neonatal period, and the early development of the gastrointestinal tract. The present review concludes that there are a number of interplaying factors relating to the anatomy and physiology of the primiparous sow and of GP themselves. The studies presented herein strongly suggest that poor support of piglet growth in utero and reduced colostrum and milk production and consumption are largely responsible for the underperformance of GP. It is therefore recommended that future management strategies focus on supporting the primiparous sow during gestation and lactation, increasing the preweaning growth of GP to improve their ability to cope with the stressors of weaning, selection of reproductive traits such as uterine capacity to improve birth weights and ultimately GP performance, and finally, increase the longevity of sows to reduce the proportion of GP entering the herd.
初产母猪所产的第一胎仔猪，通常被称为后备母猪仔猪（gilt progeny；GP），其整体生产性能往往不如经产母猪（sow progeny；SP）的仔猪。后备母猪仔猪的生长速度一直较慢，出生和断奶体重较轻，断奶后发病率和死亡率较高。总的来说，它们的性能较差导致达到市场体重的时间较长，最终收入减少。由于母猪的高更新率，初产母猪及其仔猪在猪群中占很大比例，这对养猪业造成了重大损失。虽然性能较差的原因复杂且多方面，但很大程度上可能归因于后备母猪通常配种的年龄较小，以及这对其妊娠和哺乳期代谢的重大影响。因此，这会对仔猪本身产生负面影响。为了提高 GP 的性能，了解 GP 和 SP 之间差异的生物学基础至关重要。本综述的目的是总结已发表的文献，探讨 GP 和 SP 在生长性能和健康状况方面的差异。它还检查了妊娠和哺乳期的初产母猪，以及年轻母猪如何在支持自身生长的同时，支持她的怀孕代谢需求以及她的仔猪的生长和发育。最后，根据 GP 在子宫内、新生儿期和胃肠道早期发育方面的生长和发育，讨论了 GP 的潜在生理学。本综述得出的结论是，有许多与初产母猪和 GP 自身的解剖和生理学相关的相互作用因素。本文提出的研究强烈表明，在子宫内对仔猪生长的支持不足以及初乳和牛奶产量和消耗减少，在很大程度上导致了 GP 的性能不佳。因此，建议未来的管理策略侧重于在妊娠和哺乳期支持初产母猪，增加 GP 的断奶前生长，以提高其应对断奶应激的能力，选择子宫容量等繁殖性状，以提高产仔体重，最终提高 GP 的性能，最后，延长母猪的寿命，减少进入猪群的 GP 比例。
