School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA 5371, Australia.
School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy Campus, Roseworthy, SA 5371, Australia; Robinson Research Institute, The University of Adelaide, SA 5005, Australia.
Anim Reprod Sci. 2024 Mar;262:107434. doi: 10.1016/j.anireprosci.2024.107434. Epub 2024 Feb 13.
Increasing piglet weaning age while maintaining the reproductive efficiency of the breeding herd depends on being able to stimulate sows to ovulate during lactation without reducing subsequent pregnancy rates and litter sizes. Embryo survival is affected by the quality of the oocytes shed at ovulation, and oocyte quality is profoundly impacted by the follicular environment in which the oocyte matures. This study determined the effect of reducing suckled litter size from 11 to 7 piglets on day 18 of lactation on the ovarian follicular environment and oocyte developmental competence at day 21 of lactation. Thirty-nine, Large White X Landrace sows (parity 3.2 ± 0.2; mean ± SEM; range 2-6) had their litter size either maintained at 11 piglets (control); or reduced to seven piglets on day 18 of lactation (split wean (SW)). Sows were slaughtered on day 21 of lactation and ovaries were collected for analysis of follicular fluid composition and in vitro blastocyst development rates. There was no effect of split weaning on fertilisation rate and development to blastocyst stage; however, a greater proportion of blastocysts from control sows were classified as early blastocyst stage. Furthermore, follicular fluid concentrations of oestradiol were higher in SW sows. Together, these results indicate split weaning prior to mating in lactation alters the ovarian follicular environment and while blastocyst development rates were unaffected, embryos from control sows may be of poorer quality as indicated by a delay in development.
在维持繁殖种群的繁殖效率的同时，增加仔猪断奶日龄取决于能否在哺乳期刺激母猪排卵，而不降低随后的妊娠率和窝产仔数。胚胎存活率受排卵时排出的卵母细胞质量的影响，而卵母细胞质量受到卵母细胞成熟时的卵泡环境的极大影响。本研究确定了在哺乳期第 18 天从 11 头减少到 7 头哺乳仔猪对哺乳期第 21 天卵巢卵泡环境和卵母细胞发育能力的影响。39 头大白 X 长白母猪（胎次 3.2 ± 0.2；平均值 ± SEM；范围 2-6）的窝产仔数保持在 11 头（对照组）或在哺乳期第 18 天减少到 7 头（分窝断奶（SW））。母猪在哺乳期第 21 天被屠宰，采集卵巢进行卵泡液成分分析和体外囊胚发育率分析。分窝断奶对受精率和囊胚发育阶段没有影响；然而，对照组母猪的囊胚有更大比例被分类为早期囊胚阶段。此外，SW 母猪的卵泡液中雌二醇浓度较高。这些结果表明，哺乳期配种前分窝断奶会改变卵巢卵泡环境，尽管囊胚发育率不受影响，但对照组母猪的胚胎质量可能较差，表现为发育延迟。
